MRO Feature Parameter Description - Honor · PDF fileMRO Feature Parameter Description Issue 01 Date 2016-03-07 HUAWEI TECHNOLOGIES CO., ... 8.4.2.4 MML Command Examples

eRAN TDD

MRO Feature Parameter Description

Issue 01

Date 2016-03-07

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2016. All rights reserved.No part of this document may be reproduced or transmitted in any form or by any means without prior writtenconsent of Huawei Technologies Co., Ltd. Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.All other trademarks and trade names mentioned in this document are the property of their respectiveholders. NoticeThe purchased products, services and features are stipulated by the contract made between Huawei and thecustomer. All or part of the products, services and features described in this document may not be within thepurchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information,and recommendations in this document are provided "AS IS" without warranties, guarantees orrepresentations of any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in thepreparation of this document to ensure accuracy of the contents, but all statements, information, andrecommendations in this document do not constitute a warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.Address: Huawei Industrial Base

Bantian, LonggangShenzhen 518129People's Republic of China

Website: http://www.huawei.com

Email: [email protected]

Issue 01 (2016-03-07) Huawei Proprietary and ConfidentialCopyright © Huawei Technologies Co., Ltd.

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http://www.huawei.com

mailto:[email protected]

Contents

1 About This Document.................................................................................................................. 11.1 Scope.............................................................................................................................................................................. 11.2 Intended Audience..........................................................................................................................................................11.3 Change History............................................................................................................................................................... 11.4 Differences Between eNodeB Types.............................................................................................................................. 2

2 Overview......................................................................................................................................... 32.1 Introduction.................................................................................................................................................................... 32.2 Benefits...........................................................................................................................................................................4

3 Handover Scenario Identification.............................................................................................. 53.1 Premature Handover....................................................................................................................................................... 63.2 Delayed Handover.......................................................................................................................................................... 83.3 Unnecessary Handover................................................................................................................................................... 93.4 Ping-Pong Handover.....................................................................................................................................................113.5 Coverage-induced Abnormal Handovers......................................................................................................................11

4 Handover Handling.................................................................................................................... 134.1 Intra-RAT MRO............................................................................................................................................................134.1.1 Preprocessing.............................................................................................................................................................134.1.2 Optimization Modes.................................................................................................................................................. 144.1.3 MRO Against Premature or Delayed Handovers...................................................................................................... 154.1.3.1 Intra-Frequency MRO............................................................................................................................................ 154.1.3.2 Inter-Frequency MRO............................................................................................................................................ 174.1.4 MRO Against Ping-Pong Handovers........................................................................................................................ 184.1.4.1 Cell-Level MRO..................................................................................................................................................... 184.1.4.2 UE-Level MRO...................................................................................................................................................... 194.1.5 CIO Value Range Constraints....................................................................................................................................214.2 Inter-RAT MRO............................................................................................................................................................224.2.1 Preprocessing.............................................................................................................................................................224.2.2 Optimization Modes.................................................................................................................................................. 234.2.3 MRO Against Premature Handovers.........................................................................................................................244.2.4 MRO Against Delayed Handovers............................................................................................................................ 244.2.5 MRO Against Unnecessary Handovers.....................................................................................................................254.2.6 MRO Against Ping-Pong Handovers........................................................................................................................ 26

eRAN TDDMRO Feature Parameter Description Contents


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5 Result Monitoring....................................................................................................................... 275.1 Intra-RAT MRO............................................................................................................................................................275.1.1 Parameter Setting Rollback....................................................................................................................................... 275.1.2 Penalty on Ping-Pong Parameter Adjustments..........................................................................................................285.2 Inter-RAT MRO............................................................................................................................................................28

6 Related Features...........................................................................................................................29

7 Network Impact........................................................................................................................... 31

8 Engineering Guidelines for Intra-RAT MRO........................................................................338.1 When to Use Intra-RAT MRO......................................................................................................................................338.1.1 Intra-Frequency MRO............................................................................................................................................... 338.1.2 Inter-Frequency MRO............................................................................................................................................... 348.1.3 UE-Level MRO......................................................................................................................................................... 348.2 Required Information................................................................................................................................................... 358.3 Planning........................................................................................................................................................................ 358.3.1 RF Planning............................................................................................................................................................... 358.3.2 Network Planning...................................................................................................................................................... 358.3.3 Hardware Planning.................................................................................................................................................... 358.4 Deployment.................................................................................................................................................................. 358.4.1 Requirements............................................................................................................................................................. 368.4.2 Data Preparation and Feature Activation...................................................................................................................368.4.2.1 Data Preparation..................................................................................................................................................... 368.4.2.2 Using the CME....................................................................................................................................................... 408.4.2.3 Using MML Commands.........................................................................................................................................408.4.2.4 MML Command Examples.................................................................................................................................... 418.4.3 Activation Observation..............................................................................................................................................418.4.3.1 Intra-Frequency MRO............................................................................................................................................ 418.4.3.2 Inter-Frequency MRO............................................................................................................................................ 478.4.3.3 UE-Level MRO...................................................................................................................................................... 478.4.4 Deactivation...............................................................................................................................................................498.4.4.1 Using the CME....................................................................................................................................................... 498.4.4.2 Using MML Commands.........................................................................................................................................498.4.4.3 MML Command Examples.................................................................................................................................... 508.5 Performance Monitoring...............................................................................................................................................508.5.1 Intra-Frequency MRO............................................................................................................................................... 518.5.2 Inter-Frequency MRO............................................................................................................................................... 538.5.3 UE-Level MRO......................................................................................................................................................... 538.6 Parameter Optimization................................................................................................................................................538.6.1 Intra-Frequency MRO............................................................................................................................................... 588.6.2 Inter-Frequency MRO............................................................................................................................................... 608.6.3 UE-Level MRO......................................................................................................................................................... 618.7 Troubleshooting............................................................................................................................................................ 62



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9 Engineering Guidelines for Inter-RAT MRO........................................................................659.1 When to Use Inter-RAT MRO......................................................................................................................................659.2 Required Information................................................................................................................................................... 669.3 Planning........................................................................................................................................................................ 669.3.1 RF Planning............................................................................................................................................................... 669.3.2 Network Planning...................................................................................................................................................... 679.3.3 Hardware Planning.................................................................................................................................................... 679.4 Deployment.................................................................................................................................................................. 679.4.1 Requirements............................................................................................................................................................. 679.4.2 Data Preparation and Feature Activation...................................................................................................................679.4.2.1 Data Preparation..................................................................................................................................................... 679.4.2.2 Using the CME....................................................................................................................................................... 689.4.2.3 Using MML Commands.........................................................................................................................................699.4.2.4 MML Command Examples.................................................................................................................................... 699.4.3 Activation Observation..............................................................................................................................................709.4.4 Deactivation...............................................................................................................................................................709.4.4.1 Using the CME....................................................................................................................................................... 709.4.4.2 Using MML Commands.........................................................................................................................................709.4.4.3 MML Command Examples.................................................................................................................................... 709.5 Performance Monitoring...............................................................................................................................................719.6 Parameter Optimization................................................................................................................................................739.7 Troubleshooting............................................................................................................................................................ 75

10 Parameters...................................................................................................................................77

11 Counters.................................................................................................................................... 102

12 Glossary.....................................................................................................................................110

13 Reference Documents............................................................................................................. 111



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1 About This Document

1.1 ScopeThis document describes the TDLOFD-002005 Mobility Robust Optimization (MRO) feature,including its technical principles, related features, network impact, and engineeringguidelines.

This document applies to the following types of eNodeBs.

eNodeB Type Model

Macro DBS3900 LTE TDD

Micro BTS3205E

LampSite DBS3900 LampSite TDD

Any managed objects (MOs), parameters, alarms, or counters described below correspond tothe software release delivered with this document. Any future updates will be described in theproduct documentation delivered with the latest software release.

This document applies only to LTE TDD. Any "LTE" in this document refers to LTE TDD,and "eNodeB" refers to LTE FDD eNodeB.

1.2 Intended AudienceThis document is intended for personnel who:

l Need to understand the features described hereinl Work with Huawei products

1.3 Change HistoryThis section provides information about the changes in different document versions. There aretwo types of changes:

eRAN TDDMRO Feature Parameter Description 1 About This Document


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l Feature changeChanges in features and parameters of a specified version as well as the affected entities.

l Editorial changeChanges in wording or addition of information and any related parameters affected byeditorial changes. Editorial change does not specify the affected entities.

eRAN TDD 11.1 01 (2016-03-07)

This issue does not include any changes.

eRAN TDD 11.1 Draft A (2015-12-30)

Compared with Issue 01 (2015-09-20) of eRAN TDD 11.0, Draft A (2015-12-30) of eRANTDD 11.1 includes the following changes.

ChangeType

Change Description Parameter Change AffectedEntity

Featurechange

Changed the MO to which theCellAlgoSwitch.MroSwitch parameterbelongs.

The MO to which theCellAlgoSwitch.MroSwitch parameterbelongs is changedfrom theENodeBAlgoSwitchMO to theCellAlgoSwitch MO.

N/A

Added a function subset Intra-RATMRO Measurement. For details, see8.5 Performance Monitoring.

None N/A

Editorialchange

Optimized the document structure anddescriptions.

None -

1.4 Differences Between eNodeB Types

Feature Support by Macro, Micro, and LampSite eNodeBsFeature ID Feature Description Supported

by MacroeNodeBs

Supportedby MicroeNodeBs

Supportedby LampSiteeNodeBs

TDLOFD-002005

Mobility RobustOptimization (MRO)

Yes Yes Yes

Function Implementation in Macro, Micro, and LampSite Base Stations

None

eRAN TDDMRO Feature Parameter Description 1 About This Document


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2 Overview

2.1 IntroductionAs mobile telecommunications technologies advance, networks continue to grow andincorporate multiple radio access technologies (RATs), resulting in complicated networkmaintenance. To simplify maintenance, an LTE system must support self-organizing network(SON) technology. Mobility robustness optimization (MRO) is used for self-optimization inan SON.

Mobility robustness optimization (MRO) is used to automatically optimize handoverparameters. MRO identifies scenarios of abnormal handovers and optimizes settings ofhandover-related parameters for these scenarios.

MRO processing consists of handover scenario identification, handover scenario handling,and result monitoring, as shown in Figure 2-1.

Figure 2-1 Processing procedure for MRO algorithm

To adapt to different networking modes, MRO is classified into intra-RAT MRO and inter-RAT MRO.

eRAN TDDMRO Feature Parameter Description 2 Overview


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2.2 BenefitsMRO reduces the number of abnormal handovers, providing better resource utilization andimproving user experience.

eRAN TDDMRO Feature Parameter Description 2 Overview


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3 Handover Scenario Identification

Handover scenario identification is a process to identify and accumulate the numbers ofvarious handover attempts, successful handovers, premature handovers, delayed handovers,handovers to wrong cells, ping-pong handovers, and coverage-induced abnormal handovers.

eRAN TDDMRO Feature Parameter Description 3 Handover Scenario Identification


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3.1 Premature HandoverTable 3-1 describes premature handover types.

Table 3-1 Descriptions of premature handover types

Scenario

Resultof theHandover to theTargetCell

Duration of Stayin the Target Cell

RRCReestablishment To

Cause Applicable To

Figure3-1

Failed None Target cell Signal qualityin the targetcell is poor.

Intra-RATMRO andInter-RATMRO

Figure3-2

Succeeded

The camping time isless than the value ofMRO.IntraRatHoTooEarlyTimeThd.

Target cell Signal qualityin the targetcell is unstable.

Intra-RATMRO

Figure3-3

Succeeded

The camping time isless than the value ofMRO.IntraRatHoTooEarlyTimeThd.

Third-party cell The probabilitythat the targetcell meets thehandoverconditions istoo high.

Intra-RATMRO

Type 1

Figure 3-1 Process of a premature handover (type 1)



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Type 2


Type 3




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NOTE

Handovers of type 3 are also called handovers to a wrong cell. The following counters are measured intype 3:

l L.HHO.HoToWrgCelll L.HHO.NCell.HoToWrgCell.HoSucc

3.2 Delayed HandoverIn a delayed handover, a radio link failure (RLF) occurs in the source cell and then the RRCconnection is reestablished in another cell. In this case, handover parameter settings are toostrict. As a result, the UE has moved out of the source cell but fails to trigger a handover.Table 3-2 describes delayed handover types.

Table 3-2 Descriptions of delayed handover types

Scenario

Resultof theHandover to theTargetCell

Duration of Stayin the Target Cell

RRCReestablishment To

Cause Applicable To

Figure3-4

Notinitiated

None Target cell Handoverparametersettings are toostrict. As aresult, the UEhas moved outof the sourcecell but thehandover fails.

Intra-RATMRO andInter-RATMRO

Figure3-5

Failed None Third-party cell Signal qualityin the targetcell is unstableand third-partycells cannotmeet thehandoverconditions. Asa result, the UEis handed overto a wrong cell.

Intra-RATMRO



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Type 1

Figure 3-4 Process of a delayed handover (type 1)

Type 2

Figure 3-5 Process of a delayed handover (type 2)

NOTE

Handovers of type 2 are also called handovers to a wrong cell. The following counters are measured intype 2:

l L.HHO.HoToWrgCelll L.HHO.NCell.HoToWrgCell.HoSucc

3.3 Unnecessary HandoverThis section covers only the unnecessary handovers from E-UTRAN to UTRAN.

Unnecessary inter-RAT handovers typically occur in the following scenarios: The E-UTRANcoverage is good. Inter-RAT handovers are easily triggered because of inter-RAT handoverparameter settings for E-UTRAN cells or large signal fluctuation in areas around E-UTRANcells. As a result, inter-RAT handovers are triggered although the E-UTRAN coverage is goodenough to ensure normal service provisioning.



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Figure 3-6 Scenario of unnecessary handovers

1. The UE triggers an inter-RAT handover in an LTE cell, and the handover requestmessage contains information about inter-RAT measurement configuration.

2. After the UE is handed over to UTRAN, UTRAN sends the LTE measurementconfiguration to the UE based on the received information about inter-RAT measurementconfiguration. If the LTE signal strength measured by the UE is greater than or equal tothe value of MRO.UnnecInterRatHoRsrpThd within the time specified byMRO.UnnecInterRatHoMeasTime, the handover is regarded as an unnecessaryhandover.UTRAN limits the number of measurements in compressed mode based on the LTEperiod measurement triggered by HO Report. This prevents UEs from triggering a greatnumber of measurements in compressed mode after they are handed over to E-UTRAN.If the number of UEs which are performing measurements in compressed mode isgreater than UCELLCMUSERNUM.HoReportCmUserNumThld, measurement ofunnecessary handovers is not initiated.

NOTE

For details about the compressed mode in UTRAN, see Handover Feature Parameter Description.

UTRAN in the current version cannot simultaneously start multiple measurements in compressed mode.If periodic LTE measurement triggered by HO Report is preempted by high-priority measurement incompressed mode triggered by event 2D within the duration specified byMRO.UnnecInterRatHoMeasTime, Huawei UTRAN does not send the HO Report.



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3.4 Ping-Pong Handover

Cell-Level Ping-Pong Handover

Figure 3-7 Ping-pong handover

If the duration in which the UE stayed in the target cell is less than the value ofMRO.PingpongTimeThd, the handover is regarded as a ping-pong handover.

UE-Level Ping-Pong HandoverFor the method of identifying a UE-level ping-pong handover, see 4.1.4.2 UE-Level MRO.

3.5 Coverage-induced Abnormal HandoversFigure 3-8 describes coverage-induced abnormal handovers.



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Figure 3-8 Coverage-induced Abnormal Handovers

If the signal qualities of the source cell and target cell indicated in the RLF report are less thanthe values of MRO.ServingRsrpThd and MRO.NeighborRsrpThd, respectively, the eNodeBdetermines that the RLF is a coverage-induced RLF and measures coverage-induced RLFswithin the MRO period.

During an MRO period, if the proportion of coverage-induced abnormal handovers is greaterthan the value of MRO.CoverAbnormalThd and the number of coverage-induced abnormalhandovers is greater than the total number of abnormal handovers (including premature anddelayed handovers), the eNodeB does not perform MRO within the current MRO period. Thefollowing formula is used to calculate the proportion of coverage-induced abnormalhandovers:

Proportion of coverage-induced abnormal handovers = Number of coverage-inducedabnormal handovers/(Number of premature handovers + Number of delayed handovers)

NOTE

For details about the RLF report, see 3GPP TS 36.331.



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4 Handover Handling

4.1 Intra-RAT MRO

4.1.1 Preprocessing

Handover Scenario StatisticsIf the number of handovers is greater than the value of MRO.StatNumThd in the periodspecified by MRO.OptPeriod, the MRO procedure is triggered.

NOTE

The number of handovers includes the number of handover attempts and the number of delayedhandovers.

In the early phase of network deployment, the number of handovers within an MRO periodcannot reach the value of MRO.StatNumThd in many cells. However, RLFs frequently occurin these cells. In this situation, the MRO procedure cannot be triggered in these cells if thecurrent parameter settings are retained. If users change the value of MRO.OptPeriod orMRO.StatNumThd to increase the probability of triggering MRO in these cells, incorrectMRO adjustment is more likely to occur. MRO is performed as follows:

l If the number of handovers between the pair of neighboring cells reaches the value ofMRO.StatNumThd within the first MRO period, the MRO procedure is triggered inthese cells.

l If the number of handovers between the pair of neighboring cells does not reach thevalue of MRO.StatNumThd within the first MRO period, the eNodeB retains thenumber of handovers. The MRO procedure is triggered in these cells within 30 MROperiods as long as the cumulative number of handovers reaches the value ofMRO.StatNumThd at the end of any one of the 30 periods.

l If the cumulative number of handovers within 30 MRO periods does not reach the valueof MRO.StatNumThd, the eNodeB resets the number to 0 and does not perform theMRO procedure in these cells.

eRAN TDDMRO Feature Parameter Description 4 Handover Handling


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MRO Evaluation

The eNodeB does not perform MRO at the end of an MRO period if users manuallyperformed either of the following modifications using MML commands within this MROperiod:

l Adjusting the CIO or other handover-related parameters (such as the hysteresis,threshold, offset, time-to-trigger, and filtering coefficient)

l Modifying the blacklist attributes of cells in neighboring cell pairs

In the next MRO period, the eNodeB will perform MRO based on the manual modifications.

NOTE

For details about the CIO value range, see 4.1.5 CIO Value Range Constraints.

4.1.2 Optimization ModesThe MRO optimization mode is specified by MRO.MroOptMode.

l If MRO.MroOptMode is set to FREE(FREE), the eNodeB determines parameters to beoptimized based on handover scenarios and optimizes the parameter settings when theMRO period approaches its end.

NOTE

In free mode, if EutranIntraFreqNCell.CtrlMode or EutranInterFreqNCell.CtrlMode is set toMANUAL_MODE(Manual Mode), the parameter optimization advice cannot be delivered to theeNodeBs. In this case, change the value to AUTO_MODE(Auto Mode).

l If MRO.MroOptMode is set to CONTROLLED(CONTROLLED), the eNodeBreports the parameter optimization advice to the U2000 when the MRO periodapproaches its end. After confirmation of maintenance personnel, the U2000 executesthe parameter optimization advice. Maintenance personnel can manually change thesuggested parameter values.

In controlled mode, the U2000 provides the following information:

l MRO optimization advicel Tracking area codes (TACs) of the affected local and neighboring cells for users to check

whether the cells are in a certain areal Indicator statistics used in the execution of the MRO optimization advice The following

table lists these indicators. The statistics helps determine whether the MRO optimizationadvice is proper.

Indicator Description

Total Handover numbers Total number of outgoing handoversbetween specific neighboring cells

Success Handover numbers Number of successful handovers betweenspecific neighboring cells

Too early Handover numbers Number of premature handovers betweenspecific neighboring cells

Too late Handover numbers Number of delayed handovers betweenspecific neighboring cells



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A2 Related Too late Handover numbers Number of A2-related delayed handoversbetween specific neighboring cells

Pingpong Handover numbers Number of ping-pong handovers betweenspecific neighboring cells

NOTE

l The indicator values on the U2000 accrue for consecutive MRO periods but not for the current MROperiod.

l The indicator values are collected based on handover procedures and RLFs to facilitate MRO.Therefore, the values of these indicators may be different from those of the counters described in theeNodeB performance counter reference. For example, if an RLF occurs during an intra-eNodeBhandover but the RRC connection is successfully reestablished, the eNodeB regards it as a failedhandover in indicator measurement but as a successful handover in counter measurement.

4.1.3 MRO Against Premature or Delayed Handovers

4.1.3.1 Intra-Frequency MRO

Intra-Frequency MRO includes the following optimizations:

l Handover Parameter OptimizationModify the EUTRANINTRAFREQNCELL.CellIndividualOffset parameter based onthe identification of abnormal intra-frequency handovers and statistic results.

l Reselection Parameter OptimizationCheck whether the conditions for triggering intra-frequency cell reselection match thosefor triggering intra-frequency handovers and modify theEUTRANINTRAFREQNCELL.CellQoffset parameter based on the handoverparameter optimization result.

In this document, CIO refers to the cell-specific offset for the neighboring cell. For detailsabout thresholds and CIOs related to handover events, see Intra-RAT Mobility Management inConnected Mode Feature Parameter Description.

Handover Parameter Optimization

Intra-frequency handover parameter optimization is enabled when theIntraFreqMroSwitch(IntraFreqMroAlgoSwitch) option of CellAlgoSwitch.MroSwitch isselected.

Handover parameter optimization is triggered if the following conditions are met in the periodspecified by the MRO.OptPeriod parameter:

l Number of handovers from the local cell to an intra-frequency neighboring cell ≥MRO.StatNumThd

l Proportion of RLF-related abnormal handovers > MRO.IntraRatAbnormalRatioThd

Specifically, the eNodeB performs MRO against premature or delayed handovers as follows:



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l If the proportion of the number of premature handovers to the total number of RLF-related abnormal handovers is greater than the value ofMRO.IntraRatTooEarlyHoRatioThd, the eNodeB decreases the CIO for the intra-frequency neighboring cell by one step.

l If the proportion of the number of delayed handovers to the total number of RLF-relatedabnormal handovers is greater than the value of MRO.IntraRatTooLateHoRatioThd, theeNodeB increases the CIO for the intra-frequency neighboring cell by one step.

The following formula is used to calculate the proportion of RLF-related abnormal handovers:

Proportion of RLF-related abnormal handovers = (Number of premature handovers + Numberof delayed handovers)/(Number of premature handovers + Number of delayed handovers +Number of successful handovers - Number of ping-pong handovers)

Reselection Parameter Optimization

Intra-frequency reselection parameter optimization is enabled when theIntraFreqReselOptSwitch(IntraFreqReselOptSwitch) option ofCellAlgoSwitch.MroSwitch is selected.

The reselection parameter optimization is triggered if the following conditions are met:

l Condition 1: Qhyst + CellQoffset < Min(Ocs + Off + Hys - Ocn)l Condition 2: Qhyst + CellQoffset = Min(Ocs + Off + Hys - Ocn)l Condition 3: Qhyst + CellQoffset ≥ 1

NOTE

"Min" in the preceding formulas indicates the minimum value of (Ocs + Off + Hys - Ocn) amongall handover parameter groups specified in the IntraFreqHoGroup MO in the current cell.

Table 4-1 Mapping between variables and parameters

Variable Parameter ID

Qhyst CellResel.Qhyst

CellQoffset EutranIntraFreqNCell.CellQoffset

Ocs Cell.CellSpecificOffset

Off IntraFreqHoGroup.IntraFreqHoA3Offset

Hys IntraFreqHoGroup.IntraFreqHoA3Hyst

Ocn EutranIntraFreqNCell.CellIndividualOffset

For details about Qhyst, see Idle Mode Management Feature Parameter Description.

For details about CellQoffset, Ocs, Off, Hys, and Ocn, see Intra-RAT Mobility Management inConnected Mode Feature Parameter Description.

When both the IntraFreqReselOptSwitch and IntraFreqMroSwitch options are selected,during each MRO period specified by MRO.OptPeriod, the eNodeB evaluates whether eachpair of intra-frequency neighboring cells whose CIO values need to be adjusted meetcondition 1.



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l If a pair of cells meets condition 1, the eNodeB does not optimize reselection parameters.l If a pair of cells does not meet condition 1, the eNodeB changes the CellQoffset value

for the cells to meet both conditions 2 and 3. If the cells still do not meet conditions 2and 3, the eNodeB does not optimize reselection parameters.

4.1.3.2 Inter-Frequency MROThe inter-frequency MRO function of eNodeBs is jointly controlled by theCellMro.InterFreqMroAdjParaSel parameter and theInterFreqMroSwitch(InterFreqMroAlgoSwitch) option under theCellAlgoSwitch.MroSwitch parameter. This function is used to optimize abnormal inter-frequency handovers.

When an MRO period approaches its end, the eNodeB increases the threshold for event A2and threshold 1 for event A5 in the following scenarios:

l The eNodeB increases the threshold for event A2 to decrease the number of A2-relateddelayed handovers if all of the following conditions are met:

a. The cumulative number of handovers reaches the threshold specified byMRO.StatNumThd. The method for measuring the cumulative number ofhandovers is the same as that in intra-frequency MRO scenarios. For details, see4.1.3.1 Intra-Frequency MRO.

b. Proportion of A2-related inter-frequency delayed handovers >MRO.InterFreqMeasTooLateHoThd

c. Proportion of RLF-related inter-frequency abnormal handovers >MRO.IntraRatAbnormalRatioThd

l The eNodeB increases threshold 1 for event A5 to decrease the number of A5-relatedthreshold 1-based delayed handovers if all of the following conditions are met:


b. Proportion of A2-related inter-frequency delayed handovers ≤MRO.InterFreqMeasTooLateHoThd

c. Proportion of A5-related threshold 1-based inter-frequency delayed handovers >MRO.InterFreqMeasTooLateHoThd

d. Proportion of RLF-related inter-frequency abnormal handovers >MRO.IntraRatAbnormalRatioThd

l The eNodeB increases the CIO for A2-unrelated delayed handovers by one step if all ofthe following conditions are met:



c. Proportion of A5-related threshold 1-based inter-frequency delayed handovers ≤MRO.InterFreqMeasTooLateHoThd

d. Proportion of A2-unrelated inter-frequency delayed handovers ≥MRO.IntraRatTooLateHoRatioThd



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e. Proportion of RLF-related inter-frequency abnormal handovers >MRO.IntraRatAbnormalRatioThd

l The eNodeB decreases the CIO for premature handovers by one step if all of thefollowing conditions are met:



c. Proportion of A5-related threshold 1-based inter-frequency delayed handovers ≤MRO.InterFreqMeasTooLateHoThd

d. Proportion of inter-frequency premature handovers ≥MRO.IntraRatTooEarlyHoRatioThd

e. Proportion of RLF-related inter-frequency abnormal handovers >MRO.IntraRatAbnormalRatioThd

NOTE

l Inter-frequency MRO can be used only when handover measurement events are triggered based onthe RSRP value.

l Inter-frequency MRO optimizes A2-unrelated abnormal handovers first and then A2-related delayedhandovers during an MRO period.

l In the preceding parameter adjustment scenarios, the eNodeB adjusts the threshold for event A2 byone step (one step corresponds to 1 dB) each time and adjusts the CIO for A2-unrelated abnormalhandovers according the CIO value range defined by 3GPP TS 36.331. For details, see Intra-RATMobility Management in Connected Mode.

l During the adjustment of the threshold for event A2, the adjustment value is limited by the values ofInterFreqA2RsrpLowLimit, InterFreqA2RsrpUpLimit, A3InterFreqA2RsrpLowLimit, andA3InterFreqA2RsrpUpLimit. During MRO for A2-unrelated abnormal handovers, the CIO of thecorresponding neighboring cells must be adjusted according to the CIO value range constraints. Fordetails about the CIO value range constraints, see 4.1.5 CIO Value Range Constraints.

l Inter-frequency event A2 starts inter-frequency measurement, and inter-frequency event A1 stopsinter-frequency measurement. The MRO algorithm will not adjust the threshold for inter-frequencyevent A2 to a value greater than that for inter-frequency event A1 if the threshold for inter-frequencyevent A1 is not adjusted. If the MRO algorithm adjusts both the threshold for inter-frequency eventA2 and the threshold for inter-frequency event A1, the difference between the two thresholds is keptconstant.

l During MRO for A2-related inter-frequency delayed handovers, the number of A2-related inter-frequency delayed handovers is counted based on the number of handover parameter groups becausethe threshold for event A2 is configured at the cell level based on handover parameter groups.

4.1.4 MRO Against Ping-Pong HandoverseNodeBs perform cell-level and UE-level MRO against ping-pong handovers. UE-level MROagainst ping-pong handovers is used only in intra-frequency handover scenarios. Cell-levelMRO against ping-pong handovers and MRO against premature or delayed handovers arecontrolled by the IntraFreqMroSwitch and InterFreqMroSwitch options of theCellAlgoSwitch.MroSwitch parameter. UE-level MRO against ping-pong handovers iscontrolled by the UEMroSwitch option of the CellAlgoSwitch.MroSwitch parameter.

4.1.4.1 Cell-Level MROIf within an MRO period an eNodeB has performed MRO against premature or delayedhandovers between a local cell and the target neighboring cell, the eNodeB does not perform



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MRO against ping-pong handovers between the cells in this period. If the eNodeB has notperformed MRO against premature or delayed handovers, the eNodeB checks conditions forperforming MRO against ping-pong handovers between the cells in this period.

The eNodeB performs MRO against ping-pong handovers by decreasing the CIO for theneighboring cell by one step if all the following conditions are met:

l Number of outgoing handovers to the neighboring cell ≥ MRO.StatNumThdl Proportion of ping-pong handovers > MRO.PingpongRatioThd

Proportion of ping-pong handovers = Number of ping-pong handovers/Number ofsuccessful handovers

l Intra-frequency or inter-frequency handover success rate > MRO.NcellOptThdIntra-frequency handover success rate = Number of outgoing handovers to theneighboring cell/(Total number of outgoing handovers to an intra-frequency neighboringcell + Number of delayed handovers)Inter-frequency handover success rate = Number of outgoing handovers to theneighboring cell/(Total number of outgoing handovers to an inter-frequency neighboringcell + Number of A2-unrelated delayed handovers + Number of A3-oriented A2-relateddelayed handovers + Number of A4-oriented A2-related delayed handovers)

l Proportion of RLF-related abnormal handovers < MRO.IntraRatAbnormalRatioThd/2

If the preceding conditions are not met, MRO is not performed. Intra- and inter-frequencyMRO against ping-pong handovers use the same mechanisms, except that intra-frequencyMRO adjusts the CIO for intra-frequency event A3 whereas inter-frequency MRO adjusts theCIO for inter-frequency event A4 or A3.

4.1.4.2 UE-Level MROUE-level MRO is typically used to decrease the number of ping-pong handovers betweenintra-frequency neighboring cells. The eNodeB identifies ping-pong UEs and delivers CIOvalues to these UEs.

If MRO.UePingPongNumThd is set to N and MRO.PingpongTimeThd is set to X, theeNodeB considers a UE to be a ping-pong UE when both of the following conditions are met:

l Condition 1: Number of consecutive ping-pong handovers ≥ Nl Condition 2: Average camping time in the target cell during the most recent N ping-pong

handovers < X

Figure 4-1 shows the process for a ping-pong handover. In this example, the number ofconsecutive ping-pong handovers and average camping time in the target cell during the mostrecent N ping-pong handovers are calculated based on the latest UE historical information.



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Figure 4-1 Process for a ping-pong handover

If both condition 1 and condition 2 are met, the eNodeB considers the UE to be a ping-pongUE and decreases the CIO by one step or two steps to reduce the number of ping-ponghandovers based on the following principles:

1. The eNodeB decreases the CIO by one step if the number of consecutive ping-ponghandovers is equal to N and the average camping time in the target cell during the mostrecent N ping-pong handovers is less than the value of MRO.PingpongTimeThd.

2. The eNodeB decreases the CIO by one step if the number of consecutive ping-ponghandovers is greater than N, the average camping time in the target cell during the mostrecent N ping-pong handovers is less than the value of MRO.PingpongTimeThd, andthe average camping time in the target cell during the most recent N+1 ping-ponghandovers is greater than or equal to the value of MRO.PingpongTimeThd.

3. The eNodeB decreases the CIO by two steps if the number of consecutive ping-ponghandovers is greater than N, the average camping time in the target cell during the mostrecent N ping-pong handovers is less than the value of MRO.PingpongTimeThd, andthe average camping time in the target cell during the most recent N+1 ping-ponghandovers is less than the value of MRO.PingpongTimeThd.

NOTE

l The UE History Information IE can be viewed in the HANDOVER REQUEST message sent overthe S1 or X2 interface for an inter-eNodeB handover.

l For an intra-eNodeB handover, the UE History Information IE cannot be viewed, and therefore theeNodeB makes ping-pong handover decision based on the UE context switching history information.

l After the UE-specific CIO reaches the lower limit of the CIO value range for the intra-frequencyneighboring cell, UE-level MRO allows one further adjustment of the CIO. In this case, the UE-specific CIO can be decreased by one or two steps based on the lower limit of the CIO value rangefor the intra-frequency neighboring cell.

l A large CIO value adjustment may result in a high service drop probability. This 2 dB limit reducesthe probability of a service drop caused by poor channel quality of the reference signal (RS) before ahandover. Therefore, the UE-specific CIO value can be decreased by a maximum of 2 dB based onthe cell-level CIO.

The eNodeB takes special actions for UE-level MRO in the following scenarios:

l If a UE that has experienced a handover failure has its RRC connection reestablishedwith the source cell, the eNodeB considers that the handover failure was caused by anRLF, and then does not treat this UE as a ping-pong UE or perform UE-level MRO.

l If a UE handed over to a cell meets the ping-pong UE requirement, the eNodeB deliversthe dedicated CIO value for preventing ping-pong handovers to the UE. If the UE usingthis CIO experiences an RRC connection reestablishment that is not caused by handover



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failures and the RRC connection is successfully reestablished in this cell, the UE stilluses this CIO. Otherwise, the UE uses the cell-specific CIO.

l If the eNodeB has adjusted the CIO for cell-level MRO, the eNodeB postpones UE-levelMRO by 50 seconds to prevent MRO conflicts.

UE-level MRO brings relatively higher gains in the following scenario: A UE is located at theedges of two cells, where signal fluctuations may result in relatively more ping-ponghandovers. For example, a stationary UE continuously performs services in the handover areabetween two cells.

However, UE-level MRO may be ineffective in certain network environments. For example:

l A UE moves between two cells with significantly different signal levels.l A UE performs ping-pong handovers among multiple cells.l A UE performs ping-pong handovers for a number of times less than the UE-level MRO

criteria, for example, when a UE runs discontinuous services.

4.1.5 CIO Value Range ConstraintsConstraints are imposed on CIO values to ensure effective MRO. The user can specify theCIO value ranges, to which the eNodeB reacts as follows:

l If the user sets CELLMRO.CioAdjLowerLimit and CELLMRO.CioAdjUpperLimit tospecify the CIO value range, the eNodeB implements MRO based on the parametersettings. In this case, CELLMRO.CioAdjLimitCfgInd must be set to CFG(Configure).

l If the user does not specify the CIO value range, the eNodeB automatically calculates avalue range.

When an MRO period approaches its end, if the configured CIO is outside the adjustmentrange:

1. If the CIO needs to be adjusted far away from the lower or upper limit of the range, theeNodeB cannot change the CIO in use.

2. If the configured CIO is greater than or equal to the upper limit and the CIO in use needsto be decreased, the eNodeB increases the CIO in use by one step.

3. If the configured CIO is less than or equal to the lower limit and the CIO in use needs tobe increased, the eNodeB increases the CIO in use by one step.

Value Range for Intra-Frequency Handovers

Some parameters for intra-frequency event A3 are specific for QoS class identifiers (QCIs).The CIO value range is determined by the minimum and maximum values among the lowerand upper limits calculated for all QCIs. For details about the parameters for intra-frequencyevent A3, see Inter-RAT Mobility Management in Connected Mode Feature ParameterDescription.

The following describes how to determine the CIO value range:

l If the user expects that an intra-frequency handover is triggered when the difference ofthe measured signal quality between the neighboring and serving cells falls into therange of A to B, the user should set CellMro.CioAdjLowerLimit andCellMro.CioAdjUpperLimit according to the following formulas:– CioAdjLowerLimit = Min(Off + Ofs + Ocs - Ofn + Hys - B)



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– CioAdjUpperLimit = Max(Off + Ofs + Ocs - Ofn + Hys - A)l If the user does not set CellMro.CioAdjUpperLimit and CellMro.CioAdjLowerLimit,

the eNodeB automatically calculates the lower and upper limits according to theseformulas with A and B replaced by 2 dB and 5 dB, respectively.

Value Range for Inter-Frequency Handovers

The CIO value range for inter-frequency event A3 follows the same calculation mechanismsas the CIO value range for intra-frequency event A3.

The entering condition for event A4 is as follows: Mn + Ofn + CIO - Hys > Thresh.Generally, a neighboring cell can provide continuous services only when Mn is higher than-110 dBm. Therefore, the eNodeB calculates the upper limit of the CIO value range for eventA4 as follows: Min(Thresh + 110 - Ofn + Hys). The eNodeB takes -24 as the lower limit.

In summary, the CIO value range for inter-frequency event A4 is [-24, Min(Thresh + 110 -Ofn + Hys)].

For details about the parameters for inter-frequency events A3 and A4, see Inter-RAT MobilityManagement in Connected Mode Feature Parameter Description.

4.2 Inter-RAT MRO

4.2.1 Preprocessing

Handover Scenario Statistics

eNodeBs measure the QCI-specific numbers of premature handovers, delayed handovers, andunnecessary handovers in each identified handover scenario for each RAT. Based on themapping between QCIs and handover parameter groups, the eNodeBs calculate the number ofabnormal handovers of each type and the proportion of abnormal handovers corresponding toeach handover parameter group and determine how to adjust parameters for MRO formobility to each RAT.

In Huawei eNodeBs, MRO against premature and delayed handovers in the UTRAN/GERANis controlled by the UtranMroSwitch option of the CellAlgoSwitch.MroSwitch parameter.MRO against unnecessary inter-RAT handovers in the UTRAN is controlled by theUtranUnnecHoOptSwitch option of the CellAlgoSwitch.MroSwitch parameter.

MRO Evaluation

When one of these options is selected, the eNodeB identifies and measures abnormalhandovers to the corresponding RAT and then modifies related parameters for that RAT.When an MRO period ends, the eNodeB triggers MRO when all of the following conditionsare met (note that the following number of handovers and proportions are specific to handoverparameter groups):

l The number of handovers, including handover attempts and delayed handovers, reachesthe value of MRO.StatNumThd within the first MRO period. The method for measuringthe cumulative number of handovers is the same as that in intra-frequency MROscenarios. For details, see 4.1 Intra-RAT MRO.



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l For MRO against premature and delayed handovers, the proportion of RLF-relatedabnormal handovers is greater than or equal to the value ofMRO.InterRatAbnormalHoRatioThd.

Proportion of RLF-related abnormal handovers = (Number of premature handovers +Number of delayed handovers)/(Number of premature handovers + Number of delayedhandovers + Number of successful handovers)

l For unnecessary handovers, the proportion of RLF-induced abnormal handovers is lessthan half the value of MRO.InterRatAbnormalHoRatioThd.

The eNodeB does not perform MRO in an MRO period during which users manually adjustedthe threshold for event A2 or B1 or other handover-related parameters (such as the hysteresis,threshold, offset, time-to-trigger, and filtering coefficient) online. In the next MRO period, theeNodeB will perform MRO based on the manual modifications.

NOTE

l In eRAN8.1, the parameter for the threshold of the proportion of RLF-related abnormal handovers isconfigurable, and the default parameter value is 10%. Compared with the fixed value 1% in earlierversions, the default parameter value 10% helps decrease the probability of triggering inter-RATMRO, thereby reducing ineffective or incorrect inter-RAT MRO adjustments.

l Inter-RAT MRO can be triggered only when the number of outgoing inter-RAT handover attempts isnot 0, thereby reducing incorrect inter-RAT MRO adjustments when inter-RAT MRO is enabledmanually and redirection is used as the inter-RAT mobility policy.

4.2.2 Optimization ModesAfter you activate inter-RAT MRO, you may need to adjust parameters in a similar mannerwith that for intra-RAT MRO. For details, see 4.1 Intra-RAT MRO.

In controlled mode, the U2000 provides the following information:

l MRO optimization advice

l The following traffic statistics related to abnormal handovers:


Total Handover Number Total number of outgoing handoverscorresponding to a handover parametergroup

Success Handover Number Total number of successful handoverscorresponding to a handover parametergroup

Too early Handover numbers Total number of premature handoverscorresponding to a handover parametergroup

Too late Handover numbers Total number of delayed handoverscorresponding to a handover parametergroup

Inter-Rat A2 Handover Later Number Total number of A2-related delayedhandovers corresponding to a handoverparameter group



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Unnecessary InterRat Handover Number Total number of unnecessary inter-RAThandovers corresponding to a handoverparameter group

4.2.3 MRO Against Premature HandoversAfter the MRO triggering conditions are met, the eNodeB increases the QCI-specificthreshold for event B1 by one step for MRO against premature handovers, if both of thefollowing conditions are met:

l Proportion of A2-related delayed handovers < MRO.InterRatMeasTooLateHoThdProportion of A2-related delayed handovers = Number of A2-related delayed handovers/(Number of premature handovers + Number of delayed handovers)

l Number of premature inter-RAT handovers > Threshold for the premature handoverproportionNumber of premature inter-RAT handovers = Number of premature handovers/(Numberof premature handovers + Number of A2-related delayed handovers + Number of B1-related delayed handovers)

NOTE

The threshold for the premature handover proportion has a fixed value of 70%. You cannot changethe value. In earlier versions, the eNodeB determines how to adjust parameters by comparing thenumbers of premature handovers and delayed handovers. In the current version, the probability oftriggering inter-RAT MRO decreases, and therefore ineffective or incorrect inter-RAT MROadjustments are reduced.

4.2.4 MRO Against Delayed Handovers

MRO Against A2-related Delayed HandoversAfter the MRO triggering conditions are met, the eNodeB increases the QCI-specificthreshold for inter-RAT event A2 by one step for MRO against A2-related delayed handovers,if both of the following conditions are met:

l Proportion of A2-related delayed handovers > MRO.InterRatMeasTooLateHoThdl Threshold for event A2 < Threshold for event A1

NOTE

l Inter-RAT event A2 starts inter-RAT measurement, and inter-RAT event A1 stops inter-RATmeasurement. The MRO algorithm will not adjust the threshold for event A2 to a value greater thanthat for event A1. For details about the parameters for events A1 and A2, see Inter-RAT MobilityManagement in Connected Mode.

l In eRAN8.1, the parameter for the threshold of the proportion of A2-related delayed handovers isconfigurable, and the default parameter value is 20%. Compared with the fixed value 5% in earlierversions, the default parameter value 20% helps decrease the probability of triggering inter-RATMRO, thereby reducing ineffective or incorrect inter-RAT MRO adjustments.



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MRO Against B1-related Delayed Handovers

After the MRO triggering conditions are met, the eNodeB decreases the QCI-specificthreshold for event B1 by one step for MRO against B1-related delayed handovers, if both ofthe following conditions are met:

l Proportion of A2-related delayed handovers < MRO.InterRatMeasTooLateHoThdl Proportion of B1-related delayed handovers > Threshold for the delayed handover

proportionProportion of B1-related delayed handovers = (Number of B1-related delayed handovers+ Number of A2-related delayed handovers)/(Number of premature handovers + Numberof A2-related delayed handovers + Number of B1-related delayed handovers)

NOTE

The threshold for the delayed handover proportion has a fixed value of 70%. You cannot changethe value.

MRO Against B2-related Delayed Handovers

After the MRO triggering conditions are met, the eNodeB increases the QCI-specificthreshold for event B2 by one step for MRO against B2-related threshold 1-based delayedhandovers, if both of the following conditions are met:

l Proportion of A2-related delayed handovers < Threshold for A2-related delayedhandover proportion

l Proportion of B2-related threshold 1-based delayed handovers > Threshold for A2-related delayed handover proportionProportion of B2-related threshold 1-based delayed handovers = Number of B2-relatedthreshold 1-based delayed handovers/(Number of premature handovers + Number ofdelayed handovers)

After the MRO triggering conditions are met, the eNodeB decreases the QCI-specificthreshold for event B2 by one step for MRO against B2-related threshold 2-based delayedhandovers, if both of the following conditions are met:

l Proportion of A2-related delayed handovers < Threshold for A2-related delayedhandover proportion

l Proportion of B2-related threshold 1-based delayed handovers ≤ Threshold for A2-related delayed handover proportion

l Proportion of B2-related threshold 2-based delayed handovers > Threshold for delayedhandover proportionProportion of B2-related delayed handovers = (Number of B2-related threshold 1-baseddelayed handovers + Number of B2-related threshold 2-based delayed handovers +Number of A2-related delayed handovers)/(Number of premature handovers + Numberof A2-related delayed handovers + Number of B2-related delayed handovers)

4.2.5 MRO Against Unnecessary HandoversAfter the MRO triggering conditions are met, the eNodeB decreases the threshold for eventA2 by one step for MRO against unnecessary inter-RAT handovers, if both of the followingconditions are met:

l Inter-RAT handover success rate ≥ MRO.UnnecInterRatHoOptThd



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Inter-RAT handover success rate = Number of successful inter-RAT handovers/Numberof inter-RAT handover attempts

l Proportion of unnecessary inter-RAT handovers ≥ MRO.UnnecInterRatHoRatioThdProportion of unnecessary inter-RAT handovers = Number of unnecessary inter-RAThandovers/Number of inter-RAT handover attempts

4.2.6 MRO Against Ping-Pong HandoversIn the current version, MRO against ping-pong handovers is not supported, but countersrelated to ping-pong inter-RAT handovers are measured.



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5 Result Monitoring

5.1 Intra-RAT MRO

5.1.1 Parameter Setting RollbackParameter setting rollback adjusts the threshold for event A2 for inter-frequency MRO.

l To reduce the delivering of invalid inter-RAT measurements, the eNodeB decreases thethreshold for event A2 when all of the following conditions are met:


b. The proportion of A2-related inter-frequency delayed handovers is less than thevalue of MRO.InterFreqA2RollBackThd.

c. The proportion of RLF-related abnormal handovers is less than half the value ofMRO.IntraRatAbnormalRatioThd.Proportion of RLF-related abnormal handovers = (Number of premature handovers+ Number of delayed handovers)/(Number of premature handovers + Number ofdelayed handovers + Number of successful handovers - Number of ping-ponghandovers)

d. The preceding three conditions are met within n consecutive MRO periods (where nis specified by MRO.InterFreqA2RollBackPeriod). Specifically, the precedingconditions are met when each MRO period approaches its end, and the cumulativenumber of handovers reaches the threshold specified by MRO.StatNumThd.

l If performance deteriorates, for example, the proportion of RLF-related abnormalhandovers or A2-related delayed handovers increases during an MRO period after therollback, the eNodeB considers that the performance deterioration is caused by therollback and therefore reverts the threshold to the pre-rollback value.

eRAN TDDMRO Feature Parameter Description 5 Result Monitoring


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5.1.2 Penalty on Ping-Pong Parameter Adjustments

Cell-Level PenaltyThe ping-pong modification of parameters may occur during MRO periods. The eNodeBmonitors the latest three parameter adjustments during MRO periods. If the last value isidentical with the first value, the eNodeB assumes that a ping-pong parameter adjustmentoccurred. As a penalty, the eNodeB will not perform MRO throughout the next two MROperiods, each specified by MRO.OptPeriod. During the penalty period, the eNodeB does notperform MRO.

UE-Level PenaltyWhen a UE-level MRO period (4 hours) approaches its end, the eNodeB calculates theproportion of RLFs caused by delayed handovers as follows:

Proportion of RLFs due to delayed handovers caused by UE-level MRO against ping-ponghandovers = Number of such delayed handovers/(Number of times the CIO is decreased byone step + Number of times the CIO is decreased by two steps)

l "Number of such delayed handovers" is the number of delayed handovers that occurafter UE-level MRO against ping-pong handovers is performed in all the cells under theeNodeB within the period.

l "Number of times the CIO is decreased by one step" is the number of times the eNodeBdecreases the CIO by one step for UE-level MRO within the period.

l "Number of times the CIO is decreased by two steps" is the number of times the eNodeBdecreases the CIO by two steps for UE-level MRO within the period.

The preceding values are collected in the eNodeB and cannot be observed.

If the proportion of RLFs due to delayed handovers caused by UE-level MRO against ping-pong handovers exceeds 5% (fixed), the eNodeB postpones the UE-level ping-pong handoverMRO for two periods.

If the eNodeB delivered the adjusted CIOs to some UEs before imposing a UE-level penalty,the eNodeB does not change the CIOs back to their original values.

5.2 Inter-RAT MROThe eNodeB rolls back the parameter settings if MRO against any type of inter-RATabnormal handover is triggered during an MRO period and the following condition is met:

Proportion of RLF-related abnormal handovers during the current MRO period ≥ Proportionof RLF-related abnormal handovers during the previous MRO period

eRAN TDDMRO Feature Parameter Description 5 Result Monitoring


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6 Related Features

Prerequisite Features

None

Mutually Exclusive Features

None

Impacted Features

Feature ID Feature Name Description

TDLBFD-002018 Mobility Management The MRO feature adjusts CIO-relatedparameters and therefore it affects thisfeature.

TDLOFD-001019 PS Inter-RAT Mobilitybetween E-UTRAN andUTRAN

The MRO feature adjusts CIO-relatedparameters and therefore it affects thisfeature.

TDLOFD-001020 PS Inter-RAT Mobilitybetween E-UTRAN andGERAN


TDLOFD-001032 Intra-LTE LoadBalancing


TDLOFD-001044 Inter-RAT Load Sharingto UTRAN


TDLOFD-001045 Inter-RAT Load Sharingto GERAN


TDLOFD-001036 RAN Sharing withCommon Carrier


eRAN TDDMRO Feature Parameter Description 6 Related Features


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Feature ID Feature Name Description

TDLOFD-001037 RAN Sharing withDedicated Carrier


MRO is closely related to mobility management in connected mode. MRO is performed basedon all the parameter values initially set for mobility management in connected mode, and theparameter adjustments by MRO affect mobility management in connected mode.

The identification of premature intra-RAT handovers of type 2 is affected if inter-frequencyhandovers based on frequency priorities are enabled and the blind handover policy is used orif inter-frequency MLB is enabled and the blind handover policy is used. If a blind handoveris triggered based on frequency priorities or based on inter-frequency MLB and the UE campson the target cell for a short period of time during which an RLF occurs and reestablishesconnections in a third-party cell or the source cell, the UE context in the source cell isreleased. In this case, the eNodeB counts the number of premature handovers. The CIOadjusted for premature handovers in the preceding scenario does not take effect for blindhandovers based on frequency priorities or based on inter-frequency MLB.

If RAN sharing is deployed, only the primary operator can modify handover parameters.

eRAN TDDMRO Feature Parameter Description 6 Related Features


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7 Network Impact

System Capacityl Intra-RAT MRO

– Intra-RAT MRO against premature handovers: If the CIO is adjusted to anexcessively small value, handovers may not be triggered even though the signalstrength in the neighboring cell is much higher than that in the source cell. In thiscase, signal quality of UEs in the source cell becomes worse. As a result, thethroughput decreases.

– Intra-RAT MRO against delayed handovers: If the CIO is adjusted to an excessivelylarge value, handovers may be triggered even though the signal strength in theneighboring cell is lower than that in the source cell. In this case, signal quality ofUEs in the target cell becomes worse. As a result, the throughput decreases. If thethreshold for event A2 is increased to an excessively large value by using inter-frequency MRO, the probability of UE initiating inter-frequency measurement inthe source cell increases. As a result, the user throughput decreases.

l Inter-RAT MRO– If inter-RAT MRO against premature handovers or unnecessary handovers is

triggered, UEs are less likely to be handed over the target system. As a result, UEscamp on the LTE system for a longer period of time, and the number of UEs in LTEcells is more likely to increase.

– If inter-RAT MRO against delayed handovers is triggered, UEs are more likely tobe handed over the target system. As a result, UEs camp on the LTE system for ashorter period of time, and the number of UEs in LTE cells is more likely todecrease.

Network PerformanceIntra-RAT MRO and inter-RAT MRO for mobility from E-UTRAN to GERAN/UTRANimproves the handover success rate and decreases the rate of service drops caused by thenumber of premature handovers, delayed handovers, handovers to wrong cells, unnecessaryhandovers, and ping-pong handovers.

l Intra-RAT MRO aims to control the proportions of RLF-induced abnormal handovers,ping-pong handovers, and A2-related delayed handovers (only for inter-frequency MRO)within the specified thresholds. MRO against premature or ping-pong handovers adjustsCIOs in an opposite direction to MRO against delayed handovers. Therefore, the numberof delayed handovers may increase and the number of handovers may decrease during

eRAN TDDMRO Feature Parameter Description 7 Network Impact


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MRO against premature or ping-pong handovers, and the number of premature or ping-pong handovers and the number of handovers may increase during MRO against delayedhandovers. When an MRO period ends, the proportions of RLF-induced abnormalhandovers and ping-pong handovers are lower than the specified thresholds.MRO against premature handovers and ping-pong handovers helps decrease the numberof premature handovers and ping-pong handovers without increasing the number ofhandover failures. The decrease in the number of ping-pong handovers helps increase thethroughput of ping-pong UEs and reduce signaling overhead over the Uu interface. TheCIO decrease, however, decreases the probability of handovers, thereby decreasing thenumber of handovers. The CIO decrease may also decrease the handover success rate.

l Inter-RAT MRO aims to control the proportions of RLF-induced abnormal handoversand unnecessary handovers within the specified thresholds. Inter-RAT MRO againstpremature handovers and unnecessary handovers will decrease the number of handoversfrom E-UTRAN to UTRAN/GERAN. Inter-RAT MRO against delayed handovers willincrease the number of handovers from E-UTRAN to UTRAN/GERAN.

eRAN TDDMRO Feature Parameter Description 7 Network Impact


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8 Engineering Guidelines for Intra-RAT

MRO

8.1 When to Use Intra-RAT MROMRO can be enabled only if an X2 interface is available between eNodeBs. If the X2interface is unavailable between eNodeBs, RLF indication messages cannot be transmittedover the X2 interface and the eNodeBs cannot count the number of premature or delayedhandovers. In this case, the MRO algorithm cannot make a correct parameter adjustment.

8.1.1 Intra-Frequency MROUse intra-frequency MRO according to the following principles: Abnormal handovers mayoccur because handover or radio frequency (RF) parameters are set inappropriately in livenetworks. In most cases, RF optimization is performed multiple times before a newcommercial network is put into service. It is recommended that intra-frequency MRO, whichoptimizes handover parameter settings, be enabled after the RF optimization.

After large-scale capacity expansion, eNodeBs whose capacities have been expanded affectthe coverage areas of the other eNodeBs. Therefore, the expansion has an impact on theneighbor relationships and handover areas of the other eNodeBs and may introduce newhandover areas. It is recommended that intra-frequency MRO be disabled and the CIOs be setto 0 for eNodeBs whose capacity will not be expanded in the network. Enable intra-frequencyMRO after the capacity expansion or RF optimization.

When a few eNodeBs or cells are added or RF optimization is performed for only a few cells,neighbor relationships and handover areas may be affected in a way similar to that in large-scale capacity expansion. Therefore, it is recommended that intra-frequency MRO be disabledand the CIOs be set to 0 for the eNodeBs affected by the capacity expansion or RFoptimization. Enable intra-frequency MRO after the capacity expansion or RF optimization.

Intra-frequency MRO cannot be used to solve RLFs due to coverage or strong interference.When such RLFs occur, it is recommended that RF optimization be performed to enhance thecoverage or mitigate the interference before intra-frequency MRO is enabled. MRO requires astable traffic model.

Before you activate intra-RAT MRO, observe traffic counters of each pair of neighboringcells, including L.HHO.NCell.HoToolate, L.HHO.NCell.HoTooearly, and

eRAN TDDMRO Feature Parameter Description 8 Engineering Guidelines for Intra-RAT MRO


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L.HHO.Ncell.PingPongHo or observe cell-level traffic counters, includingL.HHO.PingPongHo, L.HHO.HoToolate, and L.HHO.HoTooearly and check whetherproportions of abnormal handovers are greater than corresponding thresholds, such asMRO.IntraRatAbnormalRatioThd, MRO.IntraRatTooEarlyHoRatioThd, MRO.IntraRatTooLateHoRatioThd, and MRO.PingpongRatioThd. An OMR procedure istriggered only if one of the proportions of abnormal handovers is greater than the threshold.

After intra-frequency MRO is enabled in the preceding scenarios, it can be disabled until anew round of RF optimization is performed. MRO gains can be calculated with a stable trafficmodel.

When a network consists of micro and macro cells and intra-frequency MRO is enabled, theeNodeB does not adjust the CIO for an intra-frequency neighboring cell of the serving cell ifboth of the following conditions are met:

l The Cell Range Expansion parameter is not set to 0 for the neighboring cell.

l The intra-frequency neighboring cell and the serving cell are a pair of micro-macroneighboring cells.

NOTE

To facilitate comparison of MRO gains before and after MRO is enabled, you are advised to enableMRO when the handover area becomes stable. A stable handover area indicates that the traffic modelremains unchanged for more than three consecutive traffic periods, where:

l A traffic period of one day is recommended.

l A traffic model is represented by the number of handovers and the average number of UEs.

8.1.2 Inter-Frequency MROUse inter-frequency MRO according to the same principles for using intra-frequency MRO.For details, see 8.1.1 Intra-Frequency MRO.

Before you activate inter-RAT MRO, observe traffic counters of each pair of neighboringcells, including L.HHO.NCell.HoToolate, L.HHO.NCell.HoTooearly,L.HHO.Ncell.PingPongHo, and L.HHO.NCell.A2MeasHOTooLate or observe cell-leveltraffic counters, including L.HHO.PingPongHo, L.HHO.HoToolate, andL.HHO.HoTooearly and check whether proportions of abnormal handovers are greater thancorresponding thresholds, such as MRO.IntraRatAbnormalRatioThd,MRO.IntraRatTooEarlyHoRatioThd, MRO. IntraRatTooLateHoRatioThd,MRO.PingpongRatioThd, and MRO.InterFreqMeasTooLateHoThd. An OMR procedure istriggered only if one of the proportions of abnormal handovers is greater than the threshold.

8.1.3 UE-Level MROUse UE-level MRO after RF optimization is performed for a newly deployed network orwhen a newly deployed network has a large number of subscribers. The UE-level MROalgorithm adjusts the CIO value for a UE, decreasing its ping-pong handover probability andenabling it camp on a cell with higher signal quality. This algorithm effectively prevents ping-pong handovers and improves user experience.

Before enabling UE-level MRO, observe the L.HHO.NCell.PingPongHo.Consecutivecounter. Check whether there are an excessive number of consecutive ping-pong handovers onthe live network. UE-level MRO can be triggered only when there are an excessive number ofconsecutive ping-pong handovers on the live network.



34

8.2 Required Information

Intra- or Inter-Frequency MRO

Collect the following information for intra- or inter-frequency MRO:

l UE capability (whether inter-frequency handovers are supported)

l Networking (intra- or inter-frequency)

l Neighbor relationships (intra- or inter-frequency neighboring cells):

– Whether the information about neighboring cells is complete

NOTE

To transmit signaling messages such as RLF indications and handover reports over X2interfaces, eNodeBs require bidirectional neighbor relationships. For cells withunidirectional neighbor relationships, some abnormal handovers may not be counted.

– Whether there are unidirectional neighbor relationships

– Whether neighboring cells are blacklisted

– Whether No handover indicator for neighboring cells is set toPERMIT_HO_ENUM(Permit Ho)

l X2 interface status (whether the status is normal)

l Inter-frequency handover policy in inter-frequency networking(CellMro.InterFreqMroAdjParaSel is set based on the inter-frequency handoverpolicy).

UE-level MRO

Collect information about intra-frequency networking for UE-level MRO.

8.3 Planning

8.3.1 RF PlanningN/A

8.3.2 Network PlanningN/A

8.3.3 Hardware PlanningN/A

8.4 Deployment



35

8.4.1 Requirements

Operating Environment

iManagerU2000V200R014C00 or later is used.

Transmission Networking

For intra-RAT MRO, the X2 links between eNodeBs work properly.

License

The operator has purchased and activated the license for the feature listed in Table 8-1. Fordetails about how to activate a license, see License Management Feature ParameterDescription.

Table 8-1 License information for MRO

FeatureID

FeatureName

Model License Control Item NE SalesUnit

TDLOFD-002005

MobilityRobustOptimization(MRO)

LT1ST00MRO01

Mobility RobustOptimization (TDD)

eNodeB per Cell

8.4.2 Data Preparation and Feature Activation

8.4.2.1 Data Preparation

This section describes the data that you need to collect for setting parameters. Required data isdata that you must collect for all scenarios. Scenario-specific data, however, is prepareddepending on usage scenarios of the feature. Collect scenario-specific data when necessary fora specific feature deployment scenario.

There are three types of data sources:

l Network plan (negotiation not required): parameter values planned and set by theoperator

l Network plan (negotiation required): parameter values planned by the operator andnegotiated with the EPC or peer transmission equipment

l User-defined: parameter values set by users

Required Data

The following table describes the parameters that must be set in the CellMro MO to define aCIO value range for a cell.



36

Table 8-2 Data to prepare (CellMro)

ParameterName

ParameterID

DataSource

Setting Notes

Local cellID

CellMro.LocalCellId

Networkplan(negotiationnot required)

This parameter specifies the local cell ID. Ituniquely identifies a cell within an eNodeB.

CIOadjustmentrangeconfigurationindicator

CellMro.CioAdjLimitCfgInd


Indicates whether to set the upper and lowerlimits of the CIO adjustment range for thecell.It is recommended that this parameter be setto CFG.

CIOadjustmentupper limit

CellMro.CioAdjUpperLimit


Indicates the upper limit of the CIOadjustment range for the cell.To use MRO against premature handovers,delayed handovers, and ping-ponghandovers, set the CIO adjustment valuerange to [-1, 2].To use MRO against premature handoversand ping-pong handovers but not againstdelayed handovers, set the CIO adjustmentvalue range to [-2, 0].It is recommended that this parameter be setto 1dB.

CIOadjustmentlower limit

CellMro.CioAdjLowerLimit


Indicates the lower limit of the CIOadjustment range for the cell.It is recommended that this parameter be setto -2dB.

The following table describes the parameter that must be set in the MRO MO to specify theMRO optimization mode.



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Table 8-3 Data to prepare (MRO)

ParameterName

ParameterID

DataSource

Setting Notes

MROOptimization Mode

MRO.MroOptMode


l To enable the eNodeB to automaticallyoptimize handover and cell reselectionparameter settings, set this parameter toFREE(FREE).

l To enable manual confirmation before theeNodeB optimizes handover and cellreselection parameter settings, set theMRO.MroOptMode parameter toCONTROLLED(CONTROLLED).

Scenario-specific Data

Intra-Frequency MRO

The following table describes parameter that must be set in the CellAlgoSwitch MO toconfigure intra-frequency MRO.

Table 8-4 Data to prepare (CellAlgoSwitch)

ParameterName

ParameterID

Data Source Setting Notes

MROalgorithmswitch

CellAlgoSwitch.MroSwitch

Network plan(negotiation notrequired)

To enable intra-frequency MRO, selecttheIntraFreqMroSwitch(IntraFreqMroAlgoSwitch) option.To achieve consistency betweenhandover and cell reselection parametersettings, select the IntraFreqReselOptS-witch(IntraFreqReselOptSwitch) checkbox.To enable cell reselection parameteroptimization, select both theIntraFreqReselOptS-witch(IntraFreqReselOptSwitch) andIntraFreqMroSwitch(IntraFreqMroAlgoSwitch) check boxes.Note that the eNodeB collects handoverstatistics regardless of how thisparameter is set.

The following table describes the parameter that must be set in the EutranIntraFreqNCellMO to configure the control mode of intra-frequency neighbor relationships.



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Table 8-5 Data to prepare (EutranIntraFreqNCell)

ParameterName

ParameterID

DataSource

Setting Notes

ControlMode

EutranIntraFreqNCell.CtrlMode

Networkplan(negotiation notrequired)

When MRO Optimization Mode is set toFREE(FREE), set this parameter toAUTO_MODE(Auto Mode). Otherwise, theoptimization advice cannot be automaticallydelivered.

Inter-Frequency MRO

The following table describes the parameter that must be set in the CellAlgoSwitch MO toconfigure inter-frequency MRO.


ParameterName

ParameterID


MROalgorithmswitch



To enable inter-frequency MRO,select theInterFreqMroSwitch(InterFreqMroAlgoSwitch) option.Note that the eNodeB collectshandover statistics regardless ofhow this parameter is set.

The following table describes the parameter that must be set in the EutranInterFreqNCellMO to configure the control mode of inter-frequency neighbor relationships.

Table 8-7 Data to prepare (EutranInterFreqNCell)

ParameterName

ParameterID

DataSource

Setting Notes

ControlMode

EutranInterFreqNCell.CtrlMode


When MRO Optimization Mode is set toFREE(FREE), set this parameter toAUTO_MODE(Auto Mode). Otherwise, theoptimization advice cannot be automaticallydelivered.

UE-Level MRO

The following table describes the parameter that must be set in the CellAlgoSwitch MO toconfigure UE-level MRO.



39


ParameterName

ParameterID


MROalgorithmswitch



To enable UE-level MRO againstping-pong handovers, select theUEMroSwitch(UeMroAlgoSwitch) option.Note that the eNodeB collectshandover statistics regardless ofhow this parameter is set.

8.4.2.2 Using the CME

For detailed operations, see CME-based Feature Configuration.

8.4.2.3 Using MML Commandsl Activating intra-frequency MRO

1. (Optional) If the default CIO value range does not meet the network requirement, run theMOD CELLMRO command with CIO adjustment range configuration indicator setto CFG(Configure) and CIO adjustment upper limit and CIO adjustment lowerlimit set to appropriate values.

2. (Optional) Run the MOD MRO command with MRO-related parameters set toappropriate values.

3. Run the MOD CELLALGOSWITCH command with theIntraFreqMroSwitch(IntraFreqMroAlgoSwitch) option of the MRO algorithmswitch parameter selected.

4. (Optional) In free mode, if Control Mode is set to MANUAL_MODE(Manual Mode),the optimization advice delivery will fail. In this case, run the MODEUTRANINTRAFREQNCELL or MOD EUTRANINTERFREQNCELL commandwith Control Mode set to AUTO_MODE(Auto Mode).

l Activating inter-frequency MRO


2. (Optional) Run the MOD CELLMRO command with Interfreq MRO AdjustParameters Selection, Interfreq A2 RSRP Upper Limit, and Interfreq A2 RSRPLower Limit set to appropriate values.


4. Run the MOD CELLALGOSWITCH command with theInterFreqMroSwitch(InterFreqMroAlgoSwitch) option of the MRO algorithmswitch parameter selected.

5. (Optional) In free mode, if Control Mode is set to MANUAL_MODE(Manual Mode),the optimization advice delivery will fail. In this case, run the MOD



40

EUTRANINTRAFREQNCELL or MOD EUTRANINTERFREQNCELL commandwith Control Mode set to AUTO_MODE(Auto Mode).

l Activating UE-level MRO

1. (Optional) Run the MOD MRO command with MRO-related parameters, includingPingpong handover threshold and UE PingPong Number Threshold, set toappropriate values.

2. Run the MOD CELLALGOSWITCH command with theUEMroSwitch(UeMroAlgoSwitch) option of the MRO algorithm switch parameterselected.

8.4.2.4 MML Command Examples//Activating intra-frequency MROMOD CELLMRO:LOCALCELLID=0,CIOADJLIMITCFGIND=CFG,CIOADJUPPERLIMIT=dB1,CIOADJLOWERLIMIT=dB-2;MOD MRO:OPTPERIOD=1440,NCELLOPTTHD=95,STATNUMTHD=1000,PINGPONGTIMETHD=2,INTRARATTOOEARLYHORATIOTHD=70,INTRARATTOOLATEHORATIOTHD=70,INTRARATABNORMALRATIOTHD=10;MOD CELLALGOSWITCH:MROSWITCH=IntraFreqMroSwitch-1&InterFreqMroSwitch-0&UtranMroSwitch-0&GeranMroSwitch-0&UEMroSwitch-0&IntraFreqReselOptSwitch-0;MOD EUTRANINTRAFREQNCELL:CtrlMode=AUTO_MODE;MOD CELLMRO:LOCALCELLID=0,CIOADJLIMITCFGIND=CFG,CIOADJUPPERLIMIT=dB1,CIOADJLOWERLIMIT=dB-2;//Activating inter-frequency MROMOD CELLMRO:LOCALCELLID=0,CIOADJLIMITCFGIND=CFG,CIOADJUPPERLIMIT=dB1,CIOADJLOWERLIMIT=dB-2;MOD MRO:OPTPERIOD=1440,NCELLOPTTHD=95,STATNUMTHD=1000,PINGPONGTIMETHD=2,INTRARATTOOEARLYHORATIOTHD=70,INTRARATTOOLATEHORATIOTHD=70,INTRARATABNORMALRATIOTHD=10;MOD CELLALGOSWITCH:MROSWITCH=IntraFreqMroSwitch-0&InterFreqMroSwitch-1&UtranMroSwitch-0&GeranMroSwitch-0&UEMroSwitch-0&IntraFreqReselOptSwitch-0;MOD EUTRANINTERFREQNCELL:CtrlMode=AUTO_MODE;//Activating UE-level MROMOD MRO:PINGPONGTIMETHD=2, UePingPongNumThd=2;MOD CELLALGOSWITCH:MROSWITCH=IntraFreqMroSwitch-0&InterFreqMroSwitch-0&UtranMroSwitch-0&GeranMroSwitch-0&UEMroSwitch-1&IntraFreqReselOptSwitch-0;

8.4.3 Activation Observation

8.4.3.1 Intra-Frequency MROYou can use MML commands and signaling tracing or SON logs to observe the activation ofintra-frequency MRO.

Using MML Commands and Signaling TracingTo use MML commands and signaling tracing to check whether intra-frequency MRO takeseffect, perform the following steps:

Step 1 Start Uu and X2 interface tracing on the U2000 client.

The following procedure describes how to start Uu interface tracing (the method to start X2interface tracing is similar):



41

1. On the U2000 client, choose Monitor > Signaling Trace > Signaling Trace Management,as shown in Figure 8-1. The Signaling Trace window is displayed.

2. In the navigation tree, double-click Uu Interface Trace, as shown in Figure 8-2. The UuInterface Trace dialog box is displayed.

3. Select the eNodeB to be traced, set the parameters in the dialog box shown in Figure8-3, and then click Next.

4. Set parameters for the tracing task in the dialog box shown in Figure 8-4, and then clickFinish.

Figure 8-1 Choosing Signaling Trace Management



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Figure 8-2 Double-clicking Uu Interface Trace

Figure 8-3 Selecting the eNodeB to be traced



43

Figure 8-4 Setting parameters for the tracing task

Step 2 Run the LST MRO command, and view the value of MRO optimization period(min) in thecommand output.

Step 3 Within the period specified by MRO optimization period(min), observe the followingmessages:l A large number of RRC_CONN_REESTAB_REQ messages (indicated in Figure 8-5) in

the Uu interface tracing result for the source or target cell.l A large number of messages in the X2 interface tracing result for the source or target cell

as follows:– Delayed handover: many RLF_INDICATION messages, as shown in Figure 8-6.– Premature handover type 1: many HANDOVER_CANCEL messages, as shown in

Figure 8-7.– Premature handover type 2: many RLF_INDICATION and HANDOVER_REPORT

messages, as shown in Figure 8-8.

Figure 8-5 RRC_CONN_REESTAB_REQ message in the Uu interface tracingresult



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Figure 8-6 RLF_INDICATION message in the X2 interface tracing result for thetarget cell

Figure 8-7 HANDOVER_CANCEL message in the X2 interface tracing result forthe target cell

Figure 8-8 RLF_INDICATION and HANDOVER_REPORT messages in the X2interface tracing result for the source cell

Step 4 Run the LST EUTRANINTRAFREQNCELL command, and view the value of Cellindividual offset(dB) in the command output. If the value is increased or decreased by 1,intra-RAT MRO has been successfully activated.

NOTE

If the intra-frequency MRO criteria are met within an MRO period, the CIO will be changed.

----End

Using SON Logs

To use SON logs on the U2000 client to check whether intra-frequency MRO takes effect,perform the following steps:

Step 1 On the U2000 client, choose SON > SON Log. In the Query SON Log window, select MROLog from the Log Category drop-down list, as shown in Figure 8-9.



45

Figure 8-9 Choosing MRO Log

Step 2 Under Event Name, select items such as Set MRO Switch, Modify Intra-FrequencyMobility Parameters, Modify Inter-Frequency Mobility Parameters, Modify Inter-RAT(GERAN) Mobility Parameters, Modify Inter-RAT (UTRAN) Mobility Parameters, andModify Intra-Frequency Handover Reselection Parameters.

NOTE

During SON log query, the item Modify CIO has been deleted from Event Name in earlier versions.However, it is reserved on the U2000 interface to ensure version compatibility. You can query modifiedCIO values in Modify Intra-Frequency Mobility Parameters and Modify Inter-Frequency MobilityParameters.

Step 3 Export the SON log. In the SON log, you can view Event Name and Event Description.

You can check whether the corresponding MRO function has been activated as follows:

Step 4 If an MRO switch is set to ON in Event Description in the SON log, the corresponding MROfunction has been activated.

Step 5 If Modify Intra-Frequency Mobility Parameters, Modify Inter-Frequency MobilityParameters, Modify Inter-RAT (GERAN) Mobility Parameters, and Modify Inter-RAT(UTRAN) Mobility Parameters events appear in the log, the corresponding MRO functionshave been activated.



46

NOTE

Event Description in SON logs provides the measured counter values after handover parameters areoptimized using MRO. These values are the accumulated values over consecutive MRO periods but notthe measured values in the current MRO period. SON logs record TACs of the affected local andneighboring cells for users to check whether the cells are in a certain area.

----End

8.4.3.2 Inter-Frequency MROThe methods for observing the activation of inter-frequency MRO and intra-frequency MROare similar. For details, see 8.4.3.1 Intra-Frequency MRO.

8.4.3.3 UE-Level MROFor intra-eNodeB ping-pong handovers, no method is currently available for obtaining UEhistory information. Therefore, intra-eNodeB ping-pong handovers cannot be observed byviewing UE history information.

You can use X2- or S1-based handover signaling tracing to verify UE-level MRO in similarways. The X2-based verification procedure is as follows:

Step 1 Start Uu and X2 interface tracing on the U2000 client. For details about how to start a tracingtask, see the steps in Using MML Commands and Signaling Tracing.

Step 2 Check whether a CIO decrease instruction is included in the downlink RRC_CONN_RECFGmessage in the Uu tracing result. Figure 8-10 and Figure 8-11 show the instructions todecrease the CIO by 1 dB and by 2 dB, respectively.l If a CIO decrease instruction is not included in the message, ping-pong handovers did

not occur or the number of ping-pong handovers did not meet the trigger condition forUE-level MRO.

l If a CIO decrease instruction is included in the message, go to Step 3.



47

Figure 8-10 Instruction to decrease the CIO by 1 dB in the RRC_CONN_RECFG message

Figure 8-11 Instruction to decrease the CIO by 2 dB in the RRC_CONN_RECFG message

Step 3 In the X2 interface tracing result, view the UE history information that is included in theHANDOVER_REQUEST message corresponding to the RRC_CONN_RECFG message inStep 2, as shown in Figure 8-12. Check whether the UE has performed ping-pong handoversbetween the cells indicated in the history information. If ping-pong handovers occurred, UE-level intra-RAT MRO has been activated successfully.



48

Figure 8-12 UE history information in the HANDOVER_REQUEST message

When UE-level MRO is enabled, observe the value of the counterL.HHO.NCell.UeMro.Cio. If the value is not 0, UE-level parameter optimization adviceagainst ping-pong handovers has been implemented, indicating that UE-level MRO has beenactivated.

----End

8.4.4 Deactivation



8.4.4.2 Using MML Commands

Step 1 Run the MOD CELLALGOSWITCH command to turn off the MRO switch.

----End



49

8.4.4.3 MML Command ExamplesMOD CELLALGOSWITCH: LocalCellId=0, MROSWITCH=IntraFreqMroSwitch-0;

8.5 Performance MonitoringThe performance of intra-RAT MRO can be monitored by observing KPIs such as thehandover success rate and service drop rate. In addition, you are advised to observe thefollowing counters:

Counter ID Counter Name Description

1526741893 L.HHO.PingPongHo Number of intra-RAT ping-ponghandovers between a specific pairof cells

1526741894 L.HHO.HoToWrgCell Number of intra-RAT handovers toa wrong cell between two specificcells

1526741895 L.HHO.HoTooearly Number of premature intra-RAThandovers

1526741896 L.HHO.HoToolate Number of delayed intra-RAThandovers

1526728173 L.HHO.Ncell.PingPongHo Number of ping-pong handoversbetween a specific pair of cells

1526728355 L.HHO.NCell.HoToolate Number of delayed intra-RAThandovers

1526728356 L.HHO.NCell.HoTooearly Number of premature intra-RAThandovers

1526727378 L.Traffic.User.Avg Average number of UEs in a cell

1526729053 L.HHO.NCell.A2MeasHOTooLate

Number of A2-related delayedhandovers from a cell to an inter-frequency neighboring cell

1526733171 L.MeasCtrl.InterFreqA3.Coverage.Num.Total

Number of inter-frequencymeasurement configurations forevent A3

1526733172 L.MeasCtrl.InterFreqA4A5.Coverage.Num.Total

Number of inter-frequencymeasurement configurations forevent A4/A5 sent due to coverage

1526733169 L.HHO.NCell.PingPongHo.Consecutive

Number of consecutive ping-ponghandovers between two specificcells



50


1526733170 L.HHO.NCell.UeMro.Cio Number of times that the anti-ping-pong-handover parameter CIO issent in two specific cells based onUE-level MRO

8.5.1 Intra-Frequency MROThe following indicators are used to evaluate intra-frequency MRO gains:

l num_ho_too_late_per_user_hour: average number of delayed intra-RAT handovers perUE per hour;

l num_ho_too_early_per_user_hour: average number of premature intra-RAT handoversper UE per hour;

l num_pingpong_ho_per_user_hour: average number of ping-pong intra-RAT handoversper UE per hour;

Intra-frequency MRO aims at optimizing these indicators in the following scenarios:

l Optimizing num_ho_too_late_per_user_hour when the proportion of RLF-relatedabnormal handovers is high with delayed handovers accounting for a majority of theabnormal handovers.

l Optimizing both num_ho_too_early_per_user_hour andnum_pingpong_ho_per_user_hour when the proportion of RLF-related abnormalhandovers is high with premature handovers accounting for a majority of the abnormalhandovers.

l Optimizing num_pingpong_ho_per_user_hour when the proportion of RLF-relatedabnormal handovers is low but the number of ping-pong handovers is higher thanexpected.

This section describes how to calculate num_ho_too_late_per_user_hour and evaluate intra-frequency MRO gains. The methods for calculating num_ho_too_early_per_user_hour andnum_pingpong_ho_per_user_hour and evaluating intra-frequency MRO gains are similar.

You can use either of the following formulas to calculate num_ho_too_late_per_user_hourwithin an evaluation period T (hours):

or

where L.HHO.HoToolate is a cell-level traffic counter used to evaluate cell-level gains afterMRO is enabled and determine top cells with abnormal handovers andL.HHO.NCell.HoToolate is a cell-level traffic counter used to evaluate abnormal handovers



51

from top source cells to neighboring cells. The counters used to evaluate prematurehandovers, ping-pong handovers, and handovers to a wrong cell are similar to those used toevaluate delayed handovers. The counters apply to both inter- and intra-RAT handovers.

NOTE

In live networks, the traffic models in weekdays are mostly different from those at weekends. Tominimize the negative impact of the difference on the accuracy of MRO performance evaluation, it isrecommended that T be set to 168, which indicates 168 hours or a week.

The intra-frequency MRO evaluation method is as follows:

1. Disable intra-frequency MRO for the first evaluation period, and calculatenum_ho_too_late_per_user_hourMrooff.

2. Enable MRO for the subsequent two evaluation periods, and calculatenum_ho_too_late_per_user_hourMroon. In the first one of the two periods, MRO adjustsparameters for optimization. In the second one of the two periods, network performancegradually improves.

3. Compare the calculated num_ho_too_late_per_user_hourMroon andnum_ho_too_late_per_user_hourMrooff values. Ifnum_ho_too_late_per_user_hourMroon is less thannum_ho_too_late_per_user_hourMrooff, the intra-frequency MRO brings gains to delayedhandovers between intra-frequency cells. If num_ho_too_late_per_user_hourMroon isgreater than or equal to num_ho_too_late_per_user_hourMrooff, the intra-frequencyMRO does not bring gains to delayed handovers between intra-frequency cells.

In the first one of the two periods, MRO adjusts parameters for optimization. In the secondone of the two periods, network performance gradually improves.

Intra-frequency MRO against premature or delayed handovers takes precedence over intra-frequency MRO against ping-pong handovers. When evaluating intra-frequency MROperformance, pay attention to the following items:

l MRO against delayed handovers adjusts CIOs in an opposite direction to MRO againstpremature or ping-pong handovers. Therefore, a decrease innum_ho_too_late_per_user_hour may result in a slight increase innum_ho_too_early_per_user_hour and num_pingpong_ho_per_user_hour.

l Similarly, a decrease in num_ho_too_early_per_user_hour andnum_pingpong_ho_per_user_hour may result in a slight increase innum_ho_too_late_per_user_hour.

l According to 3GPP TS36.331, intra-frequency MRO adjusts the CIO by one step eachtime, which is a small value. Therefore, in the second evaluation period after intra-frequency MRO is enabled, ping-pong parameter adjustments may occur on the CIO anda penalty may be imposed.

l The MRO evaluation must be based on a stable traffic model, which remains almostunchanged for two consecutive evaluation periods. If the traffic volume changessignificantly during MRO, parameter adjustment may be affected: One or moreevaluation indicators among the number of premature, delayed, or ping-pong handoversper UE per hour may fluctuate during two consecutive evaluation periods.

l In live networks, traffic models change, which may have the following results:– When MRO is disabled, the number of premature, delayed, or ping-pong handovers

may change during consecutive evaluation periods.– When MRO is enabled, the evaluation indicators may fluctuate. However, the

indicators will be optimized after the traffic volumes become stable.



52

A small change in traffic volumes brings similar changes in evaluation indicatorvalues to those when MRO is disabled.

A large change in traffic volumes may cause ineffective parameter adjustments forconsecutive MRO periods.

If obvious exceptions occur during MRO gain evaluation except the preceding items,diagnose the faults, for example, by checking traffic volume changes and improper parametersettings related to intra-frequency MRO.

8.5.2 Inter-Frequency MROThe following indicators are used to evaluate inter-frequency MRO gains:

l num_ho_too_late_per_user_hour: average number of delayed intra-RAT handovers perUE per hour;

l num_ho_too_early_per_user_hour: average number of premature intra-RAT handoversper UE per hour;

l num_pingpong_ho_per_user_hour: average number of ping-pong intra-RAT handoversper UE per hour;

l num_interfreq_A2_relative_ho_too_late_per_user_hour: average number of A2-relatedinter-frequency delayed handovers per UE per hour;

l num_interfreq_A3_coverage_measctrl _per_user_hour: average number of inter-frequency measurement configurations for event A3 per UE per hour;

l num_interfreq_A4/A5_coverage_measCtrl _per_user_hour: average number of inter-frequency measurement configurations for event A4/A5 sent due to coverage per UE perhour;

For the methods for calculating the preceding indicators, see 8.5.1 Intra-Frequency MRO.

Inter-frequency MRO against A2-related delayed handovers takes precedence over inter-frequency MRO against premature handovers that are not induced by A2 events and ping-pong handovers. Therefore, after an inter-frequency MRO period, the number of A2-relateddelayed handovers may decrease but the number of non-A2-related premature or ping-ponghandovers may increase. However, after inter-frequency MRO produces the expected result,both the number of A2-related delayed handovers and the number of non-A2-related RLFsdecrease.

8.5.3 UE-Level MROThe following indicator is used to evaluate UE-level MRO gains:

num_consecutive_pingpong_ho_per_user_hour: average number of consecutive ping-ponghandovers between two specific cells per UE per hour

For the method for calculating the preceding indicator, see 8.5.1 Intra-Frequency MRO.

8.6 Parameter OptimizationYou may need to adjust the following required parameters after you activate MRO.



53

Parameter Name

Parameter ID DataSource

Setting Notes

Ncelloptimizationthreshold

MRO.NcellOptThd

User-defined If the handover success rate is less than orequal to this threshold and the ping-ponghandover rate is greater than the specifiedthreshold, the eNodeB performs cell-levelMRO against ping-pong handovers.l A larger value of this parameter results

in a lower probability of cell-levelMRO against ping-pong handovers.

l A smaller value of this parameterresults in a higher probability of cell-level MRO against ping-ponghandovers.NOTE

If this parameter is set to a large value,MRO conditions are easily to meet,resulting in a large number of incorrectadjustments. You are advised to set thisparameter to 0. In later versions, thisparameter will no longer be used fordetermining whether to perform MROagainst premature or delayed handovers.

MROoptimization period

MRO.OptPeriod

User-defined This parameter specifies the MRO period.l If the network is newly deployed or the

number of UEs is small, set thisparameter to a smaller value for morefrequent scenario identification andparameter adjustments.

l If handover performance is stable or thenetwork is mature, set this parameter toa larger value to prevent needlessperformance fluctuations.

Use this parameter withMRO.StatNumThd. If the number ofoutgoing handovers is less thanMRO.StatNumThd within an MRO periodspecified by MRO.OptPeriod, the eNodeBaccumulates the number of outgoinghandovers within the next period.



54

Parameter Name


Setting Notes

MROstatisticsnumberthreshold

MRO.StatNumThd

User-defined The eNodeB starts MRO evaluation onlywhen the number of outgoing handovers isgreater than or equal to theMRO.StatNumThd value.l If the network is newly deployed or the

number of UEs is few, set thisparameter to a smaller value for morefrequent parameter adjustments.However, if the parameter value is toosmall, the statistics on handover successrate may lead to unexpected MROresults.

l For example, a value that should beincreased is actually decreased. Ifhandover performance is stable or thenetwork is mature, set this parameter toa larger value to prevent needlessperformance fluctuations.

Use this parameter with MRO.OptPeriod.The eNodeB starts MRO evaluation onlywhen the number of outgoing handoverswithin consecutive MRO periods specifiedby MRO.OptPeriod is greater than orequal to MRO.StatNumThd.

Abnormalcoveragethreshold

MRO.CoverAbnormalThd

User-defined This parameter specifies the threshold forthe percentage of coverage-inducedabnormal handovers to all abnormalhandovers from the serving cell to aneighboring cell. If the percentage exceedsthis threshold when an MRO periodapproaches its end, the eNodeB does notadjust MRO-related parameters of theneighboring cell within this period.



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Parameter Name


Setting Notes

ServingcellRSRPthreshold

MRO.ServingRsrpThd

User-defined This parameter is used to identify thecoverage condition of the last serving cellthat a UE stayed in. After a UE experiencesan RLF or handover failure and thensuccessfully reestablishes an RRCconnection or accesses the network again,the UE sends an RLF report, whichincludes the RSRP values of the servingand neighboring cells. If the RSRP value ofthe serving cell is less than this parametervalue and the RSRP value of theneighboring cell is less than theMRO.NeighborRsrpThd parameter value,this RLF or handover failure is induced byabnormal coverage rather thaninappropriate MRO configurations.

Neighbour cellRSRPthreshold

MRO.NeighborRsrpThd

User-defined This parameter is used to identify thecoverage condition between the lastserving and neighboring cells. After a UEthat had an RLF or handover failure has itsRRC connection successfully reestablishedor accesses the network again, the UEsends an RLF report to the current servingcell. If the RSRP of the last serving cell inthe RLF report is less thanMRO.ServingRsrpThd and the RSRP ofthe last neighboring cell is less thanMRO.NeighborRsrpThd, there is abnormalcoverage between the two cells.



56

Parameter Name


Setting Notes

IntraRatHO TooEarlyTimeThreshold

MRO.IntraRatHoTooEarlyTimeThd

User-defined This parameter is used to determinewhether an abnormal intra-RAT handoveroccurs because a UE is handed over to anunstable cell. If the time during which aUE camps on a cell after an intra-RAThandover is less than or equal to the valueof this parameter, the eNodeB considersthat the cell is unstable.A larger value of this parameter results in ahigher probability that intra-RAT MROdetermines intra-RAT handovers aspremature handovers and adjustsparameters to reduce the number ofpremature handovers.A smaller value of this parameter results ina higher probability that intra-RAT MROdetermines intra-RAT handovers asdelayed handovers and adjusts parametersto reduce the number of delayedhandovers.

IntraRatAbnormalHO RatioThreshold

MRO.IntraRatAbnormalRatioThd

User-defined This parameter specifies the threshold ofthe proportion of abnormal intra-RAThandovers. If the proportion of abnormalhandovers is higher than the threshold,MRO against abnormal intra-RAThandovers is enabled. If the proportion ofthe abnormal handovers is lower than orequal to the threshold, MRO againstabnormal intra-RAT handovers is notenabled. Abnormal handovers includedelayed handovers and prematurehandovers.If this parameter is set to a large value,intra-RAT MRO is difficult to be triggered,thereby decreasing the probability ofincorrect adjustment.If this parameter is set to a small value,intra-RAT MRO is easy to be triggered,thereby increasing the probability ofincorrect adjustment.



57

Parameter Name


Setting Notes

IntraRatToo EarlyHO RatioThreshold

MRO.IntraRatTooEarlyHoRatioThd

User-defined This parameter specifies the threshold ofthe proportion of premature intra-RAThandovers. If the proportion of thepremature intra-RAT handovers is higherthan this threshold and the current cellindividual offset (CIO) is greater than theCIO adjustment threshold, MRO againstpremature handovers is enabled. If theproportion of the premature intra-RAThandovers is lower than or equal to thethreshold, MRO against prematurehandovers is not enabled.It is recommended that this parameter beset to 50% or larger values. If thisparameter is set to a large value, MROagainst premature handovers is difficult tobe triggered. If this parameter is set to asmall value, MRO against prematurehandovers is easy to be triggered.

IntraRatToo LateHO RatioThreshold

MRO.IntraRatTooLateHoRatioThd

User-defined This parameter specifies the threshold ofthe proportion of delayed intra-RAThandovers. If the proportion of the delayedintra-RAT handovers is higher than thisthreshold and the current cell individualoffset (CIO) is less than the CIOadjustment threshold, MRO againstdelayed handovers is enabled. If theproportion of the delayed intra-RAThandovers is lower than or equal to thethreshold, MRO against delayed handoversis not enabled.It is recommended that this parameter beset to 50% or larger values. If thisparameter is set to a large value, MROagainst delayed handovers is difficult to betriggered. If this parameter is set to a smallvalue, MRO against delayed handovers iseasy to be triggered.

8.6.1 Intra-Frequency MROYou may need to adjust the following parameters after you have activated intra-frequencyMRO.



58

Parameter Name

Parameter ID

DataSource

Setting Notes

Pingpongratiothreshold

MRO.PingpongRatioThd

User-defined

The eNodeB performs MRO against ping-ponghandovers when the proportion of ping-ponghandovers is greater than this parameter value.l To increase the probability of MRO against

ping-pong handovers, set this parameter to asmaller value. However, if this parameter valueis too small, an unexpected MRO result mayoccur.

l To decrease the probability of MRO againstping-pong handovers, set this parameter to alarger value.

Pingponghandoverthreshold

MRO.PingpongTimeThd

User-defined

It is recommended that this parameter be set to 2(unit: s).This parameter specifies the duration threshold forthe eNodeB to regard a handover as a ping-ponghandover.l If a UE is handed back over after staying in the

target cell for a period shorter than thisthreshold, the eNodeB determines that a ping-pong handover occurred. To enable the eNodeBto identify more ping-pong handovers, set thisparameter to a larger value. However, if thisparameter value is too large, the eNodeB maymistake the normal movement of UEs betweenneighboring cells as ping-pong handovers.

l To enable the eNodeB to identify fewer ping-pong handovers, set this parameter to a smallervalue.

This parameter takes effect immediately after beingmodified. In addition, the number of ping-ponghandovers continues to be counted into the counterL.HHO.Ncell.PingPongHo based on the modifiedthreshold.

CIOadjustment rangeconfigurationindicator

CellMro.CioAdjLimitCfgInd


To define the CIO value range, set this parameterto CFG(Configure). To use the CIO value rangecalculated by the MRO algorithm, set thisparameter to NOT_CFG(Not configure).



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Parameter Name

Parameter ID

DataSource

Setting Notes

CIOadjustment upperlimit

CellMro.CioAdjUpperLimit

User-defined

This parameter specifies the upper limit of the CIOvalue range. If there are still many delayedhandovers after the CIO is adjusted to the value ofthis parameter, increase this parameter value. Thevalue of the CioAdjUpperLimit parameter mustbe greater than that of the CioAdjLowerLimitparameter.

CIOadjustment lowerlimit

CellMro.CioAdjLowerLimit

User-defined

This parameter specifies the lower limit of the CIOvalue range. If there are still many prematurehandovers after the CIO is adjusted to the value ofthis parameter, decrease this parameter value.CioAdjLowerLimit must be less thanCioAdjUpperLimit.

8.6.2 Inter-Frequency MROYou may need to adjust the following parameters besides the parameters described in 8.6.1Intra-Frequency MRO after activating inter-frequency MRO.

ParameterName


Setting Notes

Inter frequencymeasurement toolate handoverthreshold

MRO.InterFreqMeasTooLateHoThd

User-defined

It is recommended that thisparameter set to 20 (unit: %).A larger value of this parameterindicates a lower probability thatthe event A2 threshold adjustmentis triggered by inter-frequencyMRO.

Inter frequencyA2 rollbackthreshold

MRO.InterFreqA2RollBackThd

User-defined

It is recommended that thisparameter set to 2 (unit %).This parameter indicates thethreshold of event A2 rollbacktriggered by inter-frequencyMRO.



60

ParameterName


Setting Notes

Inter FrequencyA2 RollbackPeriod

MRO.InterFreqA2RollBackPeriod

User-defined

It is recommended that thisparameter be set to 1.To decrease the probability oflowering the threshold for eventA2, increase this parameter value.To increase the probability oflowering the threshold for eventA2, decrease this parametervalue.This parameter andMRO.InterFreqA2RollBackThdtake effect simultaneously fordecreasing the threshold for eventA2.

Interfreq MROAdjustParametersSelection

CellMro.InterFreqMroAdjParaSel

User-defined

If the network inter-frequencyhandover policy is based onevents A2 and A4, it isrecommended that theInterfreqA1RsrpSwitch check boxbe selected.If the network inter-frequencyhandover policy is based onevents A2 and A3, it isrecommended that theA3InterfreqA1RsrpSwitch checkbox be selected.

8.6.3 UE-Level MROYou may need to adjust the following parameter after you have activated UE-level MRO.

Parameter Name

Parameter ID

DataSource

Setting Notes

UEPingPongNumberThreshold

MRO.UePingPongNumThd

User-defined

This parameter specifies the threshold for thenumber of ping-pong handovers. If the number ofUE ping-pong handovers is greater than or equal tothe parameter value, the eNodeB regards this UEas a ping-pong UE. The default value isrecommended. If you need to change the parametervalue, a value greater than 1 is recommended.If there are a large number of ping-pong handovers,decrease the parameter value. If there are a fewping-pong handovers, increase the parameter value.



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Parameter Name

Parameter ID

DataSource

Setting Notes

Pingponghandoverthreshold

MRO.PingpongTimeThd

User-defined

This parameter specifies the time threshold for aping-pong handover. If the average stay time in thetarget cell of a UE for consecutive handover timesis shorter than this threshold, the eNodeB decidesthat this UE is a ping-pong UE.l If a UE is handed back over after staying in the

target cell for a period shorter than thisthreshold, the eNodeB determines that a ping-pong handover occurred. To enable the eNodeBto identify more ping-pong handovers, set thisparameter to a larger value. However, if thisparameter value is too large, the eNodeB maymistake the normal movement of UEs betweenneighboring cells as ping-pong handovers.

l To enable the eNodeB to identify fewer ping-pong handovers, set this parameter to a smallervalue.

8.7 Troubleshooting

Fault 1Fault description: There are a large number of intra-frequency or inter-frequency prematureand delayed handovers, but handover-related parameter values are not adjusted.

Fault handling: Identify and rectify the fault by performing the following procedure, as shownin Figure 8-13.



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Figure 8-13 Troubleshooting procedure

Step 1 Run the LST EUTRANINTRAFREQNCELL or LST EUTRANINTERFREQNCELLcommand to query neighbor relationships.l If inter-eNodeB neighboring cells are found, go to Step 2.l If intra-eNodeB neighboring cells are found, go to Step 3.l If no neighboring cell is found, configure neighbor relationships.

Step 2 Run the DSP X2INTERFACE command to query the status of the X2 interface.l If the status is normal, go to Step 3.l If the status is abnormal, refer to the suggestion for ALM-29204 X2 Interface Fault for

instructions to handle the fault.

Step 3 Run the LST EUTRANINTRAFREQNCELL or LST EUTRANINTERFREQNCELLcommand, and view the value of No handover indicator in the command output.l If the value is PERMIT_HO_ENUM, go to Step 4.l If the value is FORBID_HO_ENUM, run the MOD EUTRANINTRAFREQNCELL

or MOD EUTRANINTERFREQNCELL command to set No handover indicator toPERMIT_HO_ENUM(Permit Ho).

NOTE

Before changing the value of No handover indicator, check whether No handover indicator has been setto FORBID_HO_ENUM(Forbid Ho) for a specific purpose.



63

Step 4 If so, do not change the value. Run the LST INTRAFREQBLKCELL or LSTINTERFREQBLKCELL command to check whether the intra- or inter-frequencyneighboring cells are blacklisted.l If the cells are not blacklisted, go to Step 5.l If the cells are blacklisted, no further action is required. The eNodeB does not perform

MRO on blacklisted cells.

Step 5 Check whether ALM-29247 Cell PCI Conflict was reported in the local cell.l If the alarm was reported, refer to the handling suggestion for this alarm.l If the alarm was not reported, contact Huawei for technical support.

----End

Fault 2Fault Description It is suspected that ping-pong handovers between intra-frequency E-UTRAN cells occurred on a UE, but no CIO decrease instruction is found in the downlinkRRC_CONN_RECFG message in the Uu tracing result.

Fault Handling:

Step 1 Run the LST CELLALGOSWITCH command to query the value of UeMroAlgoSwitch:l If the value of UeMroAlgoSwitch is Off, run the MOD CELLALGOSWITCH

command to turn it on. No further action is required.l If UeMroAlgoSwitch is turned on, go to Step 2.

Step 2 Start a Uu interface tracing task to check whether the UE sent anRRC_CONN_REESTAB_REQ message during the handover.l If the UE did not send an RRC_CONN_REESTAB_REQ message, go to Step 3.l If the UE sent an RRC_CONN_REESTAB_REQ message, this UE is not a ping-pong

UE. No further action is required.

Step 3 Start an X2 tracing task, view the number of cells that the UE camped on and the campingdurations recorded in the UE history information in the HANDOVER_REQUEST message tocheck whether ping-pong handover conditions have been met.l If ping-pong handover conditions have not been met, the UE is not a ping-pong UE. No

further action is required.l If ping-pong handover conditions have been met, contact Huawei for technical support.

----End



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9 Engineering Guidelines for Inter-RAT

MRO

9.1 When to Use Inter-RAT MROIf the E-UTRAN coexists with the UTRAN or GERAN on the live network and the inter-RAThandover policy is either PS handovers or SRVCC (for services with different QCIs), and ifthe inter-RAT neighbor relationship is complete, enable inter-RAT MRO according to thefollowing suggestions:

l Inter-RAT MRO against premature and delayed handovers:

– It is recommended that inter-RAT UTRAN MRO be enabled when all of thefollowing conditions are met:

n The E-UTRAN coexists with the UTRAN only.

n The E-UTRAN or UTRAN coverage is discontinuous.

n The proportions of premature and delayed inter-RAT handovers are large.

– It is recommended that inter-RAT GERAN MRO be enabled when all of thefollowing conditions are met:

n The E-UTRAN coexists with the GERAN only.

n The E-UTRAN or GERAN coverage is discontinuous.

n The proportions of premature and delayed inter-RAT handovers are large.

– It is recommended that both inter-RAT UTRAN MRO and inter-RAT GERANMRO be enabled when all of the following conditions are met:

n The E-UTRAN coexists with the UTRAN and GERAN.

n The E-UTRAN, UTRAN, or GERAN coverage is discontinuous.

n The trigger conditions for event A2 in the UTRAN are the same as those in theGERAN. As described in 4.1.2-Delayed Handover, if the UE does not reportthe measurement report for event B1, a delayed handover occurs. In thissituation, the eNodeB cannot determine to which system the UE hasreselected, and therefore the measured number of delayed handovers is greaterthan the actual number.

eRAN TDDMRO Feature Parameter Description 9 Engineering Guidelines for Inter-RAT MRO


65

If the first two conditions are met but the trigger conditions for event A2 in theUTRAN and GERAN are different, it is recommended that only inter-RAT UTRANMRO or inter-RAT GERAN MRO be enabled.

l Inter-RAT MRO against unnecessary handoversIt is recommended that inter-RAT UTRAN MRO against unnecessary handovers beenabled when all of the following conditions are met:– The E-UTRAN coexists with the UTRAN only.– The E-UTRAN coverage is continuous.– The UTRAN supports identification of unnecessary handovers.– The proportion of unnecessary inter-RAT handovers is large.For details about requirements on the UTRAN for identification of unnecessaryhandovers, see 3GPP TS 36.413 and 3GPP TS 25.413.

NOTE

l Inter-RAT MRO against premature handovers and inter-RAT MRO against delayed handovers arecontrolled by the same inter-RAT MRO switch. Inter-RAT GERAN MRO and inter-RAT UTRANMRO are controlled by different options under the switch.

Before enabling inter-RAT MRO, observe the L.IRATHO.E2U.HoTooLate,L.IRATHO.E2U.A2MeasHOTooLate, L.IRATHO.E2U.Unnecessary.HO, andL.IRATHO.E2U.HoTooEarly counters, or the L.IRATHO.E2G.HoTooLate,L.IRATHO.E2G.A2MeasHOTooLate, and L.IRATHO.E2G.HoTooEarly counters. Checkwhether the proportion of abnormal handovers is greater than the value ofMRO.InterRatAbnormalHoRatioThd, MRO.UnnecInterRatHoOptThd,MRO.UnnecInterRatHoRatioThd, or MRO.InterRatMeasTooLateHoThd. Inter-AT MRO istriggered only if the proportion of abnormal handovers is greater than the specified threshold.

9.2 Required InformationCollect the following information for inter-RAT MRO:

l Networking (with UTRAN or GERAN)l Whether the E-UTRAN and the target system (UTRAN/GERAN) coverage is continuousl Statistics on abnormal handovers in the E-UTRAN and the target system (UTRAN/

GERAN)l Configurations of handover policies and handover parameter groups in the E-UTRAN

and the target system (UTRAN/GERAN)l Whether the UTRAN supports identification of unnecessary handovers and the RIM

procedurel Neighbor relationships with cells of that RAT:

– Whether the information about neighboring cells is complete– Whether No handover indicator for neighboring cells is set to Permit Ho

9.3 Planning

9.3.1 RF PlanningN/A



66

9.3.2 Network PlanningN/A

9.3.3 Hardware PlanningN/A

9.4 Deployment

9.4.1 Requirements

Operating EnvironmentThe OSS version must be iManager U2000 V200R015C10 or later.

Transmission NetworkingNone

LicenseThe operator has purchased and activated the license for the feature listed in Table 8-1. Fordetails about how to activate a license, see License Management Feature ParameterDescription.

Table 9-1 License information for MRO

FeatureID

FeatureName

Model License Control Item NE SalesUnit

TDLOFD-002005


LT1ST00MRO01

Mobility RobustOptimization (TDD)

eNodeB per Cell

9.4.2 Data Preparation and Feature Activation

9.4.2.1 Data PreparationThis section describes the data that you need to collect for setting parameters. Required data isdata that you must collect for all scenarios. Scenario-specific data, however, is prepareddepending on usage scenarios of the feature. Collect scenario-specific data when necessary fora specific feature deployment scenario.

There are three types data sources:

l Network plan (negotiation not required): parameter values planned and set by theoperator



67

l Network plan (negotiation required): parameter values planned by the operator andnegotiated with the EPC or peer transmission equipment

l User-defined: parameter values set by users

Required Data

The following table describes the parameter that must be set in the CellMro MO to define alocal cell identifier for a cell.

Table 9-2 Data to prepare (CellMro)

ParameterName

ParameterID

DataSource

Setting Notes

Local cellID

CellMro.LocalCellId


This parameter specifies the local cell ID. Ituniquely identifies a cell within an eNodeB.

Scenario-specific Data

The following table describes the parameter that must be set in the CellAlgoSwitch MO toconfigure inter-RAT MRO.


ParameterName

ParameterID

DataSource

Setting Notes

MROalgorithmswitch



l To enable MRO against premature anddelayed handovers from E-UTRAN toUTRAN, select theUtranMroSwitch(UtranMroSwitch)check box.

l To enable MRO for abnormal handoversfrom E-UTRAN to GERAN, select theGeranMroSwitch(GeranMroSwitch)check box.

l To enable MRO against unnecessaryhandovers from E-UTRAN to UTRAN,select the UtranUnnecHoOptS-witch(UtranUnnecHoOptSwitch) checkbox.





68

9.4.2.3 Using MML Commandsl Activating intra-frequency MRO



3. Run the MOD CELLALGOSWITCH command with theIntraFreqMroSwitch(IntraFreqMroAlgoSwitch) option of the MRO algorithmswitch parameter selected.


l Activating inter-frequency MRO


2. (Optional) Run the MOD CELLMRO command with Interfreq MRO AdjustParameters Selection, Interfreq A2 RSRP Upper Limit, and Interfreq A2 RSRPLower Limit set to appropriate values.


4. Run the MOD CELLALGOSWITCH command with theInterFreqMroSwitch(InterFreqMroAlgoSwitch) option of the MRO algorithmswitch parameter selected.


l Activating UE-level MRO

1. (Optional) Run the MOD MRO command with MRO-related parameters, includingPingpong handover threshold and UE PingPong Number Threshold, set toappropriate values.

2. Run the MOD CELLALGOSWITCH command with theUEMroSwitch(UeMroAlgoSwitch) option of the MRO algorithm switch parameterselected.

9.4.2.4 MML Command Examples//Activating intra-frequency MROMOD CELLMRO:LOCALCELLID=0,CIOADJLIMITCFGIND=CFG,CIOADJUPPERLIMIT=dB1,CIOADJLOWERLIMIT=dB-2;MOD MRO:OPTPERIOD=1440,NCELLOPTTHD=95,STATNUMTHD=1000,PINGPONGTIMETHD=2,INTRARATTOOEARLYHORATIOTHD=70,INTRARATTOOLATEHORATIOTHD=70,INTRARATABNORMALRATIOTHD=10;MOD



69

CELLALGOSWITCH:MROSWITCH=IntraFreqMroSwitch-1&InterFreqMroSwitch-0&UtranMroSwitch-0&GeranMroSwitch-0&UEMroSwitch-0&IntraFreqReselOptSwitch-0;MOD EUTRANINTRAFREQNCELL:CtrlMode=AUTO_MODE;

//Activating inter-frequency MROMOD CELLMRO:LOCALCELLID=0,CIOADJLIMITCFGIND=CFG,CIOADJUPPERLIMIT=dB1,CIOADJLOWERLIMIT=dB-2;MOD MRO:OPTPERIOD=1440,NCELLOPTTHD=95,STATNUMTHD=1000,PINGPONGTIMETHD=2,INTRARATTOOEARLYHORATIOTHD=70,INTRARATTOOLATEHORATIOTHD=70,INTRARATABNORMALRATIOTHD=10;MOD CELLALGOSWITCH:MROSWITCH=IntraFreqMroSwitch-0&InterFreqMroSwitch-1&UtranMroSwitch-0&GeranMroSwitch-0&UEMroSwitch-0&IntraFreqReselOptSwitch-0;MOD EUTRANINTERFREQNCELL:CtrlMode=AUTO_MODE;

//Activating UE-level MROMOD MRO:PINGPONGTIMETHD=2, UePingPongNumThd=2;MOD CELLALGOSWITCH:MROSWITCH=IntraFreqMroSwitch-0&InterFreqMroSwitch-0&UtranMroSwitch-0&GeranMroSwitch-0&UEMroSwitch-1&IntraFreqReselOptSwitch-0;

9.4.3 Activation ObservationThe methods for observing the activation of inter-RAT MRO and intra-frequency MRO aresimilar. You can use MML commands or SON logs for activation observation.

Using MML Commands

Step 1 Run the LST INTERRATHOCOMMGROUP command to query the settings of commonparameter groups related to inter-RAT handovers. Alternatively, run the LSTINTERRATHOUTRANGROUP or LST INTERRATHOGERANGROUP command toquery the settings of parameter groups related to inter-RAT handovers to UTRAN/GERAN. Ifthe settings of parameter groups related to inter-RAT handovers change during twoconsecutive MRO periods, inter-RAT MRO has taken effect.

----End

Using SON LogsThe observation using SON logs for the activation of inter-RAT MRO is similar to that forintra-frequency MRO. For details, see 8.4.3.1 Intra-Frequency MRO.

9.4.4 Deactivation

9.4.4.1 Using the CMEFor detailed operations, see CME-based Feature Configuration.

9.4.4.2 Using MML Commands

Step 1 Run the MOD CELLALGOSWITCH command to turn off the MRO switch.

----End

9.4.4.3 MML Command ExamplesMOD CELLALGOSWITCH:LocalCellId=0, MROSWITCH=UtranMroSwitch-0;



70

9.5 Performance MonitoringTo monitor the performance of inter-RAT MRO, observe the following counters:

Table 9-4 Counters related to inter-RAT MRO


1526726989 L.IRATHO.E2W.PrepAttOut

Number of handoverattempts from E-UTRAN toUTRAN

1526726991 L.IRATHO.E2W.ExecSuccOut

Number of successfulhandovers from E-UTRANto UTRAN

1526727226 L.IRATHO.E2T.PrepAttOut

Number of handoverattempts from E-UTRAN toTD-SCDMA network

1526727228 L.IRATHO.E2T.ExecSuccOut

Number of successfulhandovers from E-UTRANto TD-SCDMA network

1526726992 L.IRATHO.E2G.PrepAttOut

Number of handoverattempts from E-UTRAN toGERAN

1526726994 L.IRATHO.E2G.ExecSuccOut

Number of successfulhandovers from E-UTRANto GERAN

1526737680 L.IRATHO.E2U.HoTooLate

Number of delayedhandovers from E-UTRANto UTRAN

1526737681 L.IRATHO.E2G.HoTooLate

Number of delayedhandovers from E-UTRANto GERAN

1526737682 L.IRATHO.E2U.A2MeasHOTooLate

Number of delayed A2-related handovers from E-UTRAN to UTRAN

1526737683 L.IRATHO.E2G.A2MeasHOTooLate

Number of delayed A2-related handovers from E-UTRAN to GERAN

1526737686 L.IRATHO.E2U.HoTooEarly

Number of prematurehandovers from E-UTRANto UTRAN



71


1526737687 L.IRATHO.E2G.HoTooEarly

Number of prematurehandovers from E-UTRANto GERAN

1526737684 L.IRATHO.E2U.Unnecessary.HO

Number of unnecessaryhandovers from E-UTRANto UTRAN

1526737685 L.IRATHO.E2U.Pingpong.HO

Number of ping-ponghandovers from E-UTRANto UTRAN

NOTE

l If the UTRAN/GERAN MRO switch is turned off or the UTRAN or GERAN does not exist on thecurrent network, the measured value of the L.IRATHO.E2U.A2MeasHOTooLate orL.IRATHO.E2G.A2MeasHOTooLate counter has no statistical significance. You may notsubscribe to these counters.

l Inter-RAT MRO is applicable only when handovers are triggered by RSRP. However, the measuredvalues of related counters are not restricted by handover triggering modes.

The following indicators are used to evaluate inter-RAT MRO gains. The calculation methodsare similar to those for intra-frequency MRO. For details, see 8.5.1 Intra-Frequency MRO.

l num_interRAT_ho_too_late_per_user_hour: average number of delayed inter-RAThandovers per UE per hour

l num_interRAT__ho_too_early_per_user_hour: average number of premature inter-RAThandovers per UE per hour

l num_interRAT__pingpong_ho_per_user_hour: average number of ping-pong inter-RAThandovers per UE per hour

l num_interRAT_A2_relative_ho_too_late_per_user_hour: average number of A2-relateddelayed inter-RAT handovers per UE per hour

l num_interRAT_unnecessary_ho_too_late_per_user_hour: average number ofunnecessary inter-RAT handovers per UE per hour

Similar to inter-frequency MRO, inter-frequency MRO against A2-related delayed handoverstakes precedence over MRO against non-A2-related premature or ping-pong handovers.Therefore, after an inter-frequency MRO period, the number of A2-related delayed handoversmay decrease but the number of non-A2-related premature or ping-pong handovers mayincrease. However, after inter-frequency MRO produces the expected result, both the numberof A2-related delayed handovers and the number of non-A2-related RLFs decrease.



72

9.6 Parameter OptimizationParameter Name

Parameter ID

DataSource

Setting Notes

InterRatAbnormal HORatioThreshold

MRO.InterRatAbnormalHoRatioThd

User-defined

This parameter specifies the threshold for triggeringoptimization against abnormal inter-RAT handovers.If the proportion of abnormal inter-RAT handovers isgreater than or equal to this threshold, the eNodeBdetermines whether to adjust mobility parameters.l To decrease the probability of MRO against

abnormal handovers, set this parameter to asmaller value. However, invalid adjustments mayoccur.

l To increase the probability of MRO againstabnormal handovers, set this parameter to a largervalue.

InterRatMeasurement TooLateRatioThreshold

MRO.InterRatMeasTooLateHoThd

User-defined

The unit of the value of this parameter is %. It isrecommended that this parameter be set to 20.To decrease the probability of triggering adjustmentof the threshold for event A2, set this parameter to alarger value. To increase the probability of triggeringadjustment of the threshold for event A2, set thisparameter to a smaller value.

Unnecessary IRATHoOptimizeThreshold

MRO.UnnecInterRatHoOptThd


This parameter specifies the threshold for enablingoptimization of unnecessary inter-RAT handoversbased on the inter-RAT handover success rate. If theinter-RAT handover success rate is higher than orequal to this threshold, optimization of unnecessaryinter-RAT handovers is enabled.To decrease the probability of triggering MROagainst unnecessary inter-RAT handovers, set thisparameter to a larger value. To increase theprobability of triggering MRO against unnecessaryinter-RAT handovers, set this parameter to a smallervalue.

UnnecessaryInterRatHO RatioThreshold

MRO.UnnecInterRatHoRatioThd

User-defined

This parameter specifies the threshold of theproportion of unnecessary inter-RAT handovers. Ifthe proportion of unnecessary inter-RAT handovers ishigher than this threshold, MRO against unnecessaryinter-RAT handovers is enabled.To decrease the probability of triggering MROagainst unnecessary inter-RAT handovers, set thisparameter to a larger value. To increase theprobability of triggering MRO against unnecessaryinter-RAT handovers, set this parameter to a smallervalue.



73

Parameter Name

Parameter ID

DataSource

Setting Notes

UnnecessaryInterRATHo RSRPThreshold

MRO.UnnecInterRatHoRsrpThd

User-defined

This parameter specifies the RSRP threshold fordetermining an unnecessary inter-RAT handover. If aUE is successfully handed over to a UTRAN orGERAN cell and the RSRP of an E-UTRAN cell islarger than or equal to this threshold within thespecified duration, the handover is an unnecessaryinter-RAT handover.To decrease the probability that the eNodeBdetermines an unnecessary inter-RAT handover, setthis parameter to a larger value. To increase that theeNodeB determines an unnecessary inter-RAThandover, set this parameter to a smaller value.

UnnecessaryInterRatHOMeasurementTime

MRO.UnnecInterRatHoMeasTime

User-defined

This parameter specifies the measurement time usedto determine whether an inter-RAT handover is anunnecessary handover. If a UE is successfully handedover to a UTRAN or GERAN cell and the RSRP ofan E-UTRAN cell is larger than or equal to thespecified threshold within the duration specified bythis parameter, the handover is an unnecessary inter-RAT handover.To decrease the probability that the eNodeBdetermines an unnecessary inter-RAT handover, setthis parameter to a larger value. To increase that theeNodeB determines an unnecessary inter-RAThandover, set this parameter to a smaller value.



74

Parameter Name

Parameter ID

DataSource

Setting Notes

InterRATMROStatisticsNumberThreshold

MRO.InterRatStatNumThd

User-defined

This parameter the threshold of the number ofhandovers (including outgoing handover attemptsand delayed handovers) required for enablingoptimization of inter-RAT mobility-relatedparameters. Optimization of inter-RAT mobility-related parameters is started when the number ofhandovers from the local cell to inter-RATneighboring cells reaches this threshold.l If the network is newly deployed or the number of

UEs is few, set this parameter to a smaller valuefor more frequent parameter adjustments.However, if the parameter value is too small, themeasured handover success rate has no statisticalsignificance and may lead to unexpected MROresults.

l For example, a value that should be increased isactually decreased. If handover performance isstable or the network is mature, set this parameterto a larger value to prevent needless performancefluctuations.

Use this parameter with MRO.OptPeriod. TheeNodeB triggers inter-RAT MRO only when thenumber of outgoing inter-RAT inter-cell handoverswithin consecutive MRO periods specified byMRO.OptPeriod is greater than or equal toMRO.InterRatStatNumThd.

9.7 Troubleshooting

Fault 1

Fault description: There were a large number of premature and delayed inter-RAT handovers,but the threshold for event A2 or B1 was not adjusted.

Fault handling:

Step 1 Run the LST UTRANNCELL or LST GERANNCELL command to query neighborrelationships with UTRAN or GERAN cells, respectively.l If neighboring UTRAN or GERAN cells are found and the neighbor relationship is

complete, go to Step 2.l If no neighboring UTRAN or GERAN cells are found or the neighbor relationship is

incomplete, configure neighbor relationships.

Step 2 Run the LST UTRANNCELL or LST GERANNCELL command to query the value of Nohandover indicator in the command output.l If the value is Permit Ho, go to Step 3.



75

l If the value is Forbid Ho, check whether the prohibition is reasonable.

– If it is, go to Step 3.

– If it is not, run the MOD UTRANNCELL or MOD GERANNCELL command toset No handover indicator to PERMIT_HO_ENUM(Permit Ho).

Step 3 Subscribe to and make statistics on the counters related to abnormal handovers and inter-RAThandovers.

l If the counters indicate the measurement result for premature and delayed handovers,calculate the number of abnormal handovers based on the counter values. Compare thecalculation result with the specified threshold. Determine whether the parameters relatedto MRO against abnormal handovers are configured appropriately.

– If they are, modify the related threshold parameters.

– If they are not, contact Huawei technical support.

l If the counters do not indicate the measurement result for premature and delayedhandovers, the fault handling is complete.

----End

Fault 2

Fault description: After the switch for UTRAN MRO against unnecessary inter-RAThandovers was turned on, MRO was not triggered, that is, the threshold for event A2 was notadjusted.

Fault handling:

Step 1 Check whether the UTRAN supports identification of unnecessary handovers and the RIMprocedure.

l If it does, go to Step 2.

l If it does not, the fault handling is complete.

Step 2 Run the LST UTRANNCELL command to query the neighboring relationship.

l If neighboring UTRAN cells are found and the neighbor relationship is complete, go toStep 3.

l If no neighboring UTRAN cells are found or the neighbor relationship is incomplete,configure the neighbor relationship.

Step 3 Subscribe to and make statistics on the counters related to unnecessary E-UTRAN–to–UTRAN handovers and coverage-based E-UTRAN–to–UTRAN handovers.

l If the counters indicate the measurement result for unnecessary handovers, calculate thenumber of unnecessary handovers based on the counter values. Compare the calculationresult with the specified threshold. Determine whether the parameters related to MROagainst unnecessary handovers are configured appropriately.

– If they are configured appropriately, modify the related threshold parameters.

– If they are not, contact Huawei technical support.

l If the counters do not indicate the measurement result for unnecessary handovers, thefault handling is complete.

----End



76

10 Parameters

Table 10-1 Parameters

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

CellAlgoSwitch

MroSwitch

MODCELLALGOSWITCHLSTCELLALGOSWITCH

LOFD-002005 /TDLOFD-002005


Meaning:Indicates the options for mobility robustnessoptimization (MRO) algorithms.

IntraFreqMroSwitch: If this option is selected, theeNodeB dynamically adjusts the intra-frequencyhandover parameters to increase the intra-frequencyhandover success rate. If this option is deselected, theadjustment is not performed.

InterFreqMroSwitch: If this option is selected, theeNodeB dynamically adjusts the inter-frequencyhandover parameters to increase the inter-frequencyhandover success rate. If this option is deselected, theadjustment is not performed.

UtranMroSwitch: If this option is selected, theeNodeB dynamically adjusts the UTRAN handoverparameters to increase the success rate of handovers toUTRAN. If this option is deselected, the adjustment isnot performed.

GeranMroSwitch: If this option is selected, theeNodeB dynamically adjusts the GERAN handoverparameters to increase the success rate of handovers toGERAN. If this option is deselected, the adjustment isnot performed.

UEMroSwitch: If this option is selected, the eNodeBdynamically adjusts the UE-level handover parametersto decrease the number of ping-pong handovers,thereby increasing the UEs' handover success rate. Ifthis option is deselected, the adjustment is not

eRAN TDDMRO Feature Parameter Description 10 Parameters


77

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

performed. In this version, the function of preventingping-pong handovers in the UE-level MRO algorithmtakes effect only in intra-frequency handoverscenarios.

IntraFreqReselOptSwitch: If this option is selected,the eNodeB dynamically adjusts intra-frequency cellreselection parameters, which reduces the number ofunnecessary handovers and ensures a steady handoversuccess rate. If this option is deselected, the eNodeBdoes not adjust intra-frequency cell reselectionparameters.

UtranUnnecHoOptSwitch: If this option is selected,the eNodeB dynamically adjusts parameters abouthandovers from E-UTRAN to UTRAN to reduce thenumber of unnecessary handovers from E-UTRAN toUTRAN, increase the probability that UEs camp inLTE networks, and improve user experience. If thisoption is deselected, the eNodeB does not perform theadjustment. For LTE FDD, this option takes effectonly when the UnnecHoOptWithoutRIM option isdeselected.

GeranUnnecHoOptSwitch: If this option is selected,the eNodeB dynamically adjusts parameters abouthandovers from E-UTRAN to GERAN to reduce thenumber of unnecessary handovers from E-UTRAN toGERAN, increase the probability that UEs camp inLTE networks, and improve user experience. If thisoption is deselected, the eNodeB does not perform theadjustment. In the current version, this option appliesonly to LTE TDD.

IntraRatCallbackSwtich: If this option is selected,after handover parameters are optimized in intra- orinter-frequency neighboring cells, the eNodeBmonitors the ratio of abnormal handovers within anMRO period for the neighboring cells. If the ratioincreases, the eNodeB rolls back the parametersettings. If this option is deselected, the eNodeB doesnot perform the monitoring or the parameter settingrollback. In the current version, this option appliesonly to LTE TDD.

UnnecHoOptWithoutRIM: If this option is selected,the eNodeB uses a Huawei proprietary non-RIM-based solution to reduce the number of unnecessaryinter-RAT handovers. If this option is deselected, theeNodeB uses the protocol-defined RIM-based solutionto reduce the number of unnecessary inter-RAT



78

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

handovers. LTE FDD supports only the protocol-defined scheme with RIM.GUI Value Range:IntraFreqMroSwitch(IntraFreqMroAlgoSwitch),InterFreqMroSwitch(InterFreqMroAlgoSwitch),UtranMroSwitch(UtranMroSwitch),GeranMroSwitch(GeranMroSwitch),UEMroSwitch(UeMroAlgoSwitch),IntraFreqReselOptSwitch(IntraFreqReselOptSwitch),UtranUnnecHoOptSwitch(UtranUnnecHoOptSwitch),GeranUnnecHoOptSwitch(GeranUnnecHoOptS-witch), IntraRatCallbackSwitch(IntraRatCallbackS-witch), UnnecHoOptWithou-tRIM(UnnecHoOptWithoutRIM)Unit: NoneActual Value Range: IntraFreqMroSwitch,InterFreqMroSwitch, UtranMroSwitch,GeranMroSwitch, UEMroSwitch,IntraFreqReselOptSwitch, UtranUnnecHoOptSwitch,GeranUnnecHoOptSwitch, IntraRatCallbackSwitch,UnnecHoOptWithoutRIMDefault Value: IntraFreqMroSwitch:Off,InterFreqMroSwitch:Off, UtranMroSwitch:Off,GeranMroSwitch:Off, UEMroSwitch:Off,IntraFreqReselOptSwitch:Off, UtranUnnecHoOptS-witch:Off, GeranUnnecHoOptSwitch:Off,IntraRatCallbackSwitch:Off, UnnecHoOptWithou-tRIM:Off



79

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

MRO IntraRatHoTooEarlyTimeThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning:If the time during which a UE camps on a cell after anintra-RAT handover is less than or equal to thisparameter value, the eNodeB considers that the cell isunstable.

A larger value of parameter results in a higherprobability that intra-RAT MRO determines intra-RAThandovers as premature handovers and adjustsparameters to reduce the number of prematurehandovers. This decreases the number of handoversand the probability of delayed handovers.

A smaller value of this parameter results in a higherprobability that intra-RAT MRO determines intra-RAThandovers as delayed handovers and adjustsparameters to reduce the number of delayedhandovers. This increases the number of handovers.

For details, see descriptions of "short time" in "Intra-RAT MRO use case" in 3GPP TS 36.300.GUI Value Range: 1~60Unit: sActual Value Range: 1~60Default Value: 3

MRO UnnecInterRatHoRsrpThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the reference signal receivedpower (RSRP) threshold used to determine whether aninter-RAT handover is an unnecessary handover. Afteran inter-RAT handover, if the RSRP value of thesource E-UTRAN cell measured by the UE in thetarget cell is consecutively greater than or equal to thisparameter value within the specified period of time,the eNodeB considers that the inter-RAT handover isan unnecessary handover.GUI Value Range: -140~-44Unit: dBmActual Value Range: -140~-44Default Value: -115



80

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

MRO UnnecInterRatHoMeasTime

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the measurement time used todetermine whether an inter-RAT handover is anunnecessary handover. After an inter-RAT handover,if the reference signal received power (RSRP) valueof the source E-UTRAN cell measured by the UE inthe target cell is consecutively greater than a presetthreshold within the period of time specified by thisparameter, the eNodeB considers that the inter-RAThandover is an unnecessary handover.GUI Value Range: 0~100Unit: sActual Value Range: 0~100Default Value: 2

MRO PingpongTimeThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the time threshold for ping-ponghandover. If a UE is handed over back to the sourcecell after staying in the target cell for a period shorterthan this threshold, the eNodeB decides that a ping-pong handover occurs based on the historyinformation about this UE.GUI Value Range: 1~60Unit: sActual Value Range: 1~60Default Value: 2

MRO ServingRsrpThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the reference signal receivedpower (RSRP) threshold for the serving cell. Thethreshold is used to identify abnormal coverage in aserving cell. If a UE successfully reestablishes anRRC connection or reaccess the serving cell after aradio link failure (RLF) or a handover failure, the UEsends the eNodeB an RLF report, which includes theRSRP values of the serving cell and neighboring cell.If the RSRP value of the serving cell is less than thisparameter value and the RSRP value of theneighboring cell is less than the NeighborRsrpThdparameter value, this RLF or handover failure isinduced by abnormal coverage rather thaninappropriate MRO configurations.GUI Value Range: -140~-44Unit: dBmActual Value Range: -140~-44Default Value: -116



81

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

MRO NeighborRsrpThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the reference signal receivedpower (RSRP) threshold for neighboring cells. Thethreshold is used to identify coverage-inducedabnormal handovers from the serving cell to theneighboring cell. If a UE successfully reestablishes anRRC connection or reaccess the serving cell after aradio link failure (RLF) or a handover failure, the UEsends the eNodeB an RLF report, which includes theRSRP values of the serving cell and neighboring cell.If the RSRP value of the serving cell is less than theServingRsrpThd parameter value and the RSRP valueof the neighboring cell is less than this parametervalue, this RLF is induced by abnormal coveragerather than inappropriate MRO configurations.GUI Value Range: -140~-44Unit: dBmActual Value Range: -140~-44Default Value: -116

MRO CoverAbnormalThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold for the percentage ofcoverage-induced abnormal handovers to all abnormalhandovers from the serving cell to a neighboring cell.If the percentage is greater than or equal to thisthreshold when a mobility robustness optimization(MRO) period approaches its end, the eNodeB doesnot adjust MRO-related parameters of the neighboringcell within this period.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 60



82

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

MRO OptPeriod

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the period of measurement forMRO. During the period, the number of handovers ismeasured and abnormal scenarios (includingpremature handover, delayed handover, and ping-ponghandover) are identified. After the period elapses, theeNodeB makes a decision on parameter adjustment.Itis recommended that this parameter be set to amultiple of 5. If this parameter is not set to a multipleof 5, the actually effective parameter value is extendedto a multiple of 5.GUI Value Range: 1~70000Unit: minActual Value Range: 1~70000Default Value: 1440

MRO StatNumThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold of the number ofhandovers (including outgoing handover attempts anddelayed handovers) required for enabling optimizationof intra-RAT mobility-related parameters.Optimization of intra-RAT mobility-relatedparameters is started when the number of handoversfrom the local cell to an intra-RAT neighboring cellreaches this threshold.GUI Value Range: 0~10000Unit: NoneActual Value Range: 0~10000Default Value: 1000



83

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

EutranIntraFreqNCell

CtrlMode

ADDEUTRANINTRAFREQNCELLMODEUTRANINTRAFREQNCELLLSTEUTRANINTRAFREQNCELL

LBFD-00201804/TDLBFD-00201804

DistanceBasedInter-frequencyHandover

Meaning: Indicates the control policy on ANR-relatedMOs, which can be defined by the user or be based onthe automatic neighbor relation (ANR) algorithm.When this parameter is set to MANUAL_MODE, theANR-related MOs can be modified or removed byonly the user. A failure message is displayed when theuser adds an existing MO. When this parameter is setto AUTO_MODE, the ANR-related MOs can bemodified or removed by the user or based on the ANRalgorithm. The MO removal is successful even if theMO does not exist. An MO can be added both by theuser and based on the ANR algorithm. If an existingMO is to be added, the MO is modified when the userperforms the addition, but it cannot be added based onthe ANR algorithm. When the ANR-related MOs areautomatically added based on the ANR algorithm, thisparameter is set to AUTO_MODE by default. Whenthe ANR-related MOs are added by the user, thisparameter can be set to AUTO_MODE orMANUAL_MODE.GUI Value Range: AUTO_MODE(Auto Mode),MANUAL_MODE(Manual Mode)Unit: NoneActual Value Range: AUTO_MODE,MANUAL_MODEDefault Value: AUTO_MODE(Auto Mode)



84

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

EutranInterFreqNCell

CtrlMode

ADDEUTRANINTERFREQNCELLMODEUTRANINTERFREQNCELLLSTEUTRANINTERFREQNCELL

LOFD-002001

AutomaticNeighbourRelation(ANR)

Meaning: Indicates the control policy on ANR-relatedMOs, which can be defined by the user or be based onthe automatic neighbor relation (ANR) algorithm.When this parameter is set to MANUAL_MODE, theANR-related MOs can be modified or removed byonly the user. A failure message is displayed when theuser adds an existing MO. When this parameter is setto AUTO_MODE, the ANR-related MOs can bemodified or removed by the user or based on the ANRalgorithm. The MO removal is successful even if theMO does not exist. An MO can be added both by theuser and based on the ANR algorithm. If an existingMO is to be added, the MO is modified when the userperforms the addition, but it cannot be added based onthe ANR algorithm. When the ANR-related MOs areautomatically added based on the ANR algorithm, thisparameter is set to AUTO_MODE by default. Whenthe ANR-related MOs are added by the user, thisparameter can be set to AUTO_MODE orMANUAL_MODE.GUI Value Range: AUTO_MODE(Auto Mode),MANUAL_MODE(Manual Mode)Unit: NoneActual Value Range: AUTO_MODE,MANUAL_MODEDefault Value: AUTO_MODE(Auto Mode)

MRO MroOptMode

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the mode in which MRO takeseffect. If this parameter is set to FREE, the eNodeBautomatically optimizes handover and reselectionparameters. If this parameter is set toCONTROLLED, the eNodeB only reports thehandover or reselection parameters to be optimized tothe U2000, and the U2000 delivers the optimizationon handover or cell reselection parameters after usersconfirm the optimization.GUI Value Range: FREE(FREE),CONTROLLED(CONTROLLED)Unit: NoneActual Value Range: FREE, CONTROLLEDDefault Value: FREE(FREE)



85

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description


CellIndividualOffset


LBFD-00201801/TDLBFD-00201801TDLBFD-002018

Coverage BasedIntra-frequencyHandoverMobilityManagement

Meaning: Indicates the cell individual offset for theintra-frequency neighboring cell, which is used inevaluation for handovers. It affects the probability oftriggering intra-frequency measurement reports. Alarger value of this parameter indicates a higherprobability. For details, see 3GPP TS 36.331.GUI Value Range: dB-24(-24dB), dB-22(-22dB),dB-20(-20dB), dB-18(-18dB), dB-16(-16dB),dB-14(-14dB), dB-12(-12dB), dB-10(-10dB),dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB),dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB),dB1(1dB), dB2(2dB), dB3(3dB), dB4(4dB),dB5(5dB), dB6(6dB), dB8(8dB), dB10(10dB),dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB),dB20(20dB), dB22(22dB), dB24(24dB)Unit: dBActual Value Range: dB-24, dB-22, dB-20, dB-18,dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4,dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5,dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20,dB22, dB24Default Value: dB0(0dB)



86

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description


CellQoffset


LBFD-00201801/TDLBFD-00201801

Coverage BasedIntra-frequencyHandover

Meaning: Indicates the offset for the intra-frequencyneighboring cell, which is used in evaluation for cellreselections. A larger value of this parameter results ina lower probability of cell reselections. If thisparameter is not set to dB0, it is delivered in SIB4. Fordetails, see 3GPP TS 36.331. If this parameter is set todB0, it is not delivered in SIB4. In this situation, UEsuse 0 dB as the offset for cell reselections. For details,see 3GPP TS 36.304.GUI Value Range: dB-24(-24dB), dB-22(-22dB),dB-20(-20dB), dB-18(-18dB), dB-16(-16dB),dB-14(-14dB), dB-12(-12dB), dB-10(-10dB),dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB),dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB),dB1(1dB), dB2(2dB), dB3(3dB), dB4(4dB),dB5(5dB), dB6(6dB), dB8(8dB), dB10(10dB),dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB),dB20(20dB), dB22(22dB), dB24(24dB)Unit: dBActual Value Range: dB-24, dB-22, dB-20, dB-18,dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4,dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5,dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20,dB22, dB24Default Value: dB0(0dB)

MRO IntraRatAbnormalRatioThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold of the proportion ofabnormal intra-RAT handovers. If the proportion ofabnormal handovers is higher than the threshold,MRO against abnormal intra-RAT handovers isenabled. If the proportion of the abnormal handoversis lower than or equal to the threshold, MRO againstabnormal intra-RAT handovers is not enabled.Abnormal handovers include both premature anddelayed handovers.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 10



87

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

MRO IntraRatTooEarlyHoRatioThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold of the proportion ofpremature intra-RAT handovers. If the proportion ofthe premature intra-RAT handovers is higher than thisthreshold and the current cell individual offset (CIO)is greater than the CIO adjustment threshold, mobilityparameters need to be adjusted. If the proportion ofthe premature intra-RAT handovers is less than orequal to this parameter value, mobility parameters donot need to be adjusted. If both this parameter and theIntraRatTooLateHoRatioThd parameter are set to 50%or smaller values, the conditions for optimizing bothpremature and delayed intra-RAT handovers may bemet. In this case, delayed intra-RAT handovers, whichincrease the service drop rate at a higher probabilitythan premature intra-RAT handovers, are optimized bypreference.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 70

MRO IntraRatTooLateHoRatioThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold of the proportion ofdelayed intra-RAT handovers. If the proportion of thedelayed intra-RAT handovers is higher than thisthreshold and the current cell individual offset (CIO)is less than the CIO adjustment threshold, mobilityparameters need to be adjusted. If the proportion ofdelayed intra-RAT handovers is less than or equal tothis parameter value, mobility parameters do not needto be adjusted. If both this parameter and theIntraRatTooEarlyHoRatioThd parameter are set to50% or smaller values, the conditions for optimizingboth premature and delayed intra-RAT handovers maybe met. In this case, delayed intra-RAT handovers,which increase the service drop rate at a higherprobability than premature intra-RAT handovers, areoptimized by preference.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 70



88

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

CellResel

Qhyst MODCELLRESELLSTCELLRESEL

LBFD-00201803/TDLBFD-00201803LBFD-002009 /TDLBFD-002009

CellSelection andRe-selectionBroadcast ofsysteminformation

Meaning: Indicates the hysteresis for cell reselectionwhen RSRP values are used in the evaluation. Thisparameter must be set based on the slow fadingcharacteristic of the area covered by the cell. Thegreater the slow fading variance is, the larger the valueof this parameter must be set to. A larger value of thehysteresis results in a larger boundary of the servingcell and a lower probability of cell reselection toneighboring cells.GUI Value Range: DB0_Q_HYST(0dB),DB1_Q_HYST(1dB), DB2_Q_HYST(2dB),DB3_Q_HYST(3dB), DB4_Q_HYST(4dB),DB5_Q_HYST(5dB), DB6_Q_HYST(6dB),DB8_Q_HYST(8dB), DB10_Q_HYST(10dB),DB12_Q_HYST(12dB), DB14_Q_HYST(14dB),DB16_Q_HYST(16dB), DB18_Q_HYST(18dB),DB20_Q_HYST(20dB), DB22_Q_HYST(22dB),DB24_Q_HYST(24dB)Unit: dBActual Value Range: DB0_Q_HYST, DB1_Q_HYST,DB2_Q_HYST, DB3_Q_HYST, DB4_Q_HYST,DB5_Q_HYST, DB6_Q_HYST, DB8_Q_HYST,DB10_Q_HYST, DB12_Q_HYST, DB14_Q_HYST,DB16_Q_HYST, DB18_Q_HYST, DB20_Q_HYST,DB22_Q_HYST, DB24_Q_HYSTDefault Value: DB4_Q_HYST(4dB)



89

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

Cell CellSpecificOffset

ADDCELLMODCELLLSTCELL

LBFD-00201801/TDLBFD-00201801TDLBFD-002018TDLBFD-00201802TDLBFD-00201804TDLBFD-00201805TDLOFD-001019TDLOFD-001043TDLOFD-001072TDLOFD-001020TDLOFD-001046TDLOFD-001073

Coverage BasedIntra-frequencyHandoverMobilityManagementCoverage BasedInter-frequencyHandoverDistanceBasedInter-frequencyHandoverServiceBasedInter-frequencyHandoverPS Inter-RATMobilitybetweenE-UTRANandUTRANServicebasedInter-RAThandover toUTRAN

Meaning: Indicates the cell specific offset for theserving cell. It affects the probability of triggeringhandovers from the serving cell to its neighboringcells. A smaller value of this parameter leads to ahigher probability. For details, see 3GPP TS 36.331.GUI Value Range: dB-24(-24dB), dB-22(-22dB),dB-20(-20dB), dB-18(-18dB), dB-16(-16dB),dB-14(-14dB), dB-12(-12dB), dB-10(-10dB),dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB),dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB),dB1(1dB), dB2(2dB), dB3(3dB), dB4(4dB),dB5(5dB), dB6(6dB), dB8(8dB), dB10(10dB),dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB),dB20(20dB), dB22(22dB), dB24(24dB)Unit: dBActual Value Range: dB-24, dB-22, dB-20, dB-18,dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4,dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5,dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20,dB22, dB24Default Value: dB0(0dB)



90

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

DistancebasedInter-RAThandover toUTRANPS Inter-RATMobilitybetweenE-UTRANandGERANServicebasedInter-RAThandover toGERANDistancebasedInter-RAThandover toGERAN

IntraFreqHoGroup

IntraFreqHoA3Offset

ADDINTRAFREQHOGROUPMODINTRAFREQHOGROUPLSTINTRAFREQHOGROUP

LBFD-00201801/TDLBFD-00201801


Meaning: Indicates the offset for event A3. If theparameter is set to a large value, an intra-frequencyhandover is performed only when the signal quality ofthe neighboring cell is significantly better than that ofthe serving cell and other triggering conditions aremet. For details, see 3GPP TS 36.331.GUI Value Range: -30~30Unit: 0.5dBActual Value Range: -15~15Default Value: 2



91

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

IntraFreqHoGroup

IntraFreqHoA3Hyst

ADDINTRAFREQHOGROUPMODINTRAFREQHOGROUPLSTINTRAFREQHOGROUP

LBFD-00201801/TDLBFD-00201801


Meaning: Indicates the hysteresis for intra-frequencyhandover event A3. This parameter decreases frequentevent triggering due to radio signal fluctuations andreduces the probability of handover decision errorsand ping-pong handovers. A larger value of thisparameter results in a lower probability. Thehysteresis for event inter-frequency handover eventA3 is the same as the value of this parameter. Fordetails, see 3GPP TS 36.331.GUI Value Range: 0~30Unit: 0.5dBActual Value Range: 0~15Default Value: 2



92

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

CellMro InterFreqMroAdjParaSel

MODCELLMROLSTCELLMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the selection of inter-frequencyadjustable parameters in inter-frequency MRO.InterfreqA1RsrpSwitch: Indicates whether the RSRPthreshold for triggering inter-frequency event A1 inthe inter-frequency handover parameter group can beadjusted. The RSRP threshold can be adjusted onlywhen this switch is on. InterfreqA2RsrpSwitch:Indicates whether the RSRP threshold for triggeringinter-frequency event A2 in the inter-frequencyhandover parameter group can be adjusted. The RSRPthreshold can be adjusted only when this switch is on.A3InterfreqA1RsrpSwitch: Indicates whether theRSRP threshold for triggering A3-oriented inter-frequency event A1 in the inter-frequency handoverparameter group can be adjusted. The RSRP thresholdcan be adjusted only when this switch is on.A3InterfreqA2RsrpSwitch: Indicates whether theRSRP threshold for triggering A3-oriented inter-frequency event A2 in the inter-frequency handoverparameter group can be adjusted. The RSRP thresholdcan be adjusted only when this switch is on.InterfreqA3CioSwitch: Indicates whether the cellindividual offset (CIO) of the inter-frequencyneighboring cell for inter-frequency event A3 can beadjusted. The CIO can be adjusted only when thisswitch is on. InterfreqA4CioSwitch: Indicates whetherthe CIO of the inter-frequency neighboring cell forinter-frequency event A4 can be adjusted. The CIOcan be adjusted only when this switch is on.InterfreqA5Switch: Indicates whether the CIO of theinter-frequency neighboring cell for inter-frequencyevent A5 and related threshold 1 for triggering inter-frequency event A5 can be adjusted. The CIO andrelated threshold 1 can be adjusted only when thisswitch is on.GUI Value Range:InterfreqA1RsrpSwitch(InterfreqA1RsrpSwitch),InterfreqA2RsrpSwitch(InterfreqA2RsrpSwitch),A3InterfreqA1RsrpSwitch(A3InterfreqA1RsrpSwitch),A3InterfreqA2RsrpSwitch(A3InterfreqA2RsrpSwitch), InterfreqA3CioSwitch(InterfreqA3CioSwitch),InterfreqA4CioSwitch(InterfreqA4CioSwitch),InterfreqA5Switch(InterfreqA5Switch)Unit: NoneActual Value Range: InterfreqA1RsrpSwitch,InterfreqA2RsrpSwitch, A3InterfreqA1RsrpSwitch,



93

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

A3InterfreqA2RsrpSwitch, InterfreqA3CioSwitch,InterfreqA4CioSwitch, InterfreqA5SwitchDefault Value: InterfreqA1RsrpSwitch:Off,InterfreqA2RsrpSwitch:On,A3InterfreqA1RsrpSwitch:Off,A3InterfreqA2RsrpSwitch:On,InterfreqA3CioSwitch:On, InterfreqA4CioSwitch:On,InterfreqA5Switch:On

MRO InterFreqMeasTooLateHoThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the percentage threshold ofdelayed handovers caused by low threshold of theevent A2 and delayed inter-frequency measurementsto the sum of premature handovers and delayedhandovers. If the actual percentage is greater than thisparameter value, the threshold for triggering inter-frequency event A2 is adjusted by the inter-frequencyMRO.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 5

CellMro InterFreqA2RsrpLowLimit


LOFD-002005 /TDLOFD-002005


Meaning: Indicates the lower limit used to adjust thereference signal received power (RSRP) threshold fortriggering inter-frequency event A2.GUI Value Range: -140~-43Unit: dBmActual Value Range: -140~-43Default Value: -115

CellMro InterFreqA2RsrpUpLimit


LOFD-002005 /TDLOFD-002005


Meaning: Indicates the upper limit used to adjust thereference signal received power (RSRP) threshold fortriggering inter-frequency event A2.GUI Value Range: -140~-43Unit: dBmActual Value Range: -140~-43Default Value: -99



94

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

CellMro A3InterFreqA2RsrpLowLimit


LOFD-002005 /TDLOFD-002005


Meaning: Indicates the lower limit used to adjust thereference signal received power (RSRP) threshold fortriggering A3-oriented inter-frequency event A2.GUI Value Range: -140~-43Unit: dBmActual Value Range: -140~-43Default Value: -115

CellMro A3InterFreqA2RsrpUpLimit


LOFD-002005 /TDLOFD-002005


Meaning: Indicates the upper limit used to adjust thereference signal received power (RSRP) threshold fortriggering A3-oriented inter-frequency event A2.GUI Value Range: -140~-43Unit: dBmActual Value Range: -140~-43Default Value: -89

MRO PingpongRatioThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold for the percentage ofintra-RAT ping-pong handovers. If the percentage ofintra-RAT ping-pong handovers is greater than thisparameter value, parameters are adjusted to reduce thenumber of ping-pong handovers. If the percentage isless than or equal to this parameter value, parametersare not adjusted.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 5

MRO NcellOptThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the handover success ratethreshold for enabling mobility-related parameteroptimization. If the handover success rate is greaterthan this parameter value, mobility-related parametersare optimized to reduce the number of ping-ponghandovers.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 99



95

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

MRO UePingPongNumThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold for the number ofpingpong handovers. If the number of consecutiveping-pong handovers reaches the threshold, the UE isa ping-pong UE.GUI Value Range: 1~7Unit: NoneActual Value Range: 1~7Default Value: 5

CellMro CioAdjLowerLimit


LOFD-002005 /TDLOFD-002005


Meaning: Indicates the lower limit of cell individualoffset (CIO) adjustment range for the cell in mobilityrobustness optimization (MRO). This parameter needsto be set only when the CioAdjLimitCfgInd parameteris set to CFG.GUI Value Range: dB-24(-24dB), dB-22(-22dB),dB-20(-20dB), dB-18(-18dB), dB-16(-16dB),dB-14(-14dB), dB-12(-12dB), dB-10(-10dB),dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB),dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB),dB1(1dB), dB2(2dB), dB3(3dB), dB4(4dB),dB5(5dB), dB6(6dB), dB8(8dB), dB10(10dB),dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB),dB20(20dB), dB22(22dB), dB24(24dB)Unit: dBActual Value Range: dB-24, dB-22, dB-20, dB-18,dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4,dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5,dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20,dB22, dB24Default Value: dB-24(-24dB)



96

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

CellMro CioAdjUpperLimit


LOFD-002005 /TDLOFD-002005


Meaning: Indicates the upper limit of cell individualoffset (CIO) adjustment range for the cell in mobilityrobustness optimization (MRO). This parameter needsto be set only when the CioAdjLimitCfgInd parameteris set to CFG.GUI Value Range: dB-24(-24dB), dB-22(-22dB),dB-20(-20dB), dB-18(-18dB), dB-16(-16dB),dB-14(-14dB), dB-12(-12dB), dB-10(-10dB),dB-8(-8dB), dB-6(-6dB), dB-5(-5dB), dB-4(-4dB),dB-3(-3dB), dB-2(-2dB), dB-1(-1dB), dB0(0dB),dB1(1dB), dB2(2dB), dB3(3dB), dB4(4dB),dB5(5dB), dB6(6dB), dB8(8dB), dB10(10dB),dB12(12dB), dB14(14dB), dB16(16dB), dB18(18dB),dB20(20dB), dB22(22dB), dB24(24dB)Unit: dBActual Value Range: dB-24, dB-22, dB-20, dB-18,dB-16, dB-14, dB-12, dB-10, dB-8, dB-6, dB-5, dB-4,dB-3, dB-2, dB-1, dB0, dB1, dB2, dB3, dB4, dB5,dB6, dB8, dB10, dB12, dB14, dB16, dB18, dB20,dB22, dB24Default Value: dB24(24dB)



97

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

CellMro CioAdjLimitCfgInd


LOFD-002005 /TDLOFD-002005


Meaning:Indicates whether to set the upper and lower limits ofthe CIO adjustment range for the cell.

If this parameter is set to CFG(Configure), the CIOfor the cell can be changed by an amount within therange specified by the upper and lower limits.

If this parameter is set to NOT_CFG(Not configure),the upper and lower limits of the CIO adjustmentrange for the cell in intra-frequency MRO arecalculated by using the following formulas: Lowerlimit = Off + Ofs + Ocs - Ofn + Hys - 5, Upper limit =Off + Ofs + Ocs - Ofn + Hys - 2, where Off is theoffset for intra-frequency handover, Ofs and Ofn arethe frequency-specific offsets for the servingfrequency and neighboring frequency respectively,Ocs is the cell-specific offset for the serving cell, andHys is the hysteresis for intra-frequency handover.

If this parameter is set to NOT_CFG(Not configure)and the Inter-Freq HO trigger Event Type parameter isset to EventA4(EventA4), the upper and lower limitsof the CIO adjustment range for the cell in inter-frequency MRO are calculated by using the followingformulas: Lower limit = -24, Upper limit < thresh+ 110 - Ofn + Hys, where thresh is the RSRPthreshold for triggering a coverage-based inter-frequency handover and Hys is the hysteresis for inter-frequency handover.

If this parameter is set to NOT_CFG(Not configure)and the Inter-Freq HO trigger Event Type parameter isset to EventA3(EventA3), the upper and lower limitsof the CIO adjustment range for the cell in inter-frequency MRO are calculated by using the followingformulas: Lower limit = Off + Ofs + Ocs - Ofn + Hys- 5, Upper limit = Off + Ofs + Ocs - Ofn + Hys - 2,where Off is the inter-frequency A3 offset, and Hys isthe hysteresis for intra-frequency handover.GUI Value Range: NOT_CFG(Not configure),CFG(Configure)Unit: NoneActual Value Range: NOT_CFG, CFGDefault Value: NOT_CFG(Not configure)



98

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

MRO InterRatAbnormalHoRatioThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold for triggeringoptimization against abnormal inter-RAT handovers.If the ratio of abnormal inter-RAT handovers is greaterthan or equal to this threshold, the eNodeB determineswhether to adjust mobility parameters. If the ratio ofabnormal inter-RAT handovers is less than thisthreshold, the eNodeB does not determine whether toadjust mobility parameters. Abnormal handoversinclude delayed handovers and premature handovers.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 10

MRO InterRatMeasTooLateHoThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the percentage threshold ofdelayed inter-RAT handovers caused by delayed inter-RAT measurements to the sum of abnormal inter-RAThandovers (including premature handovers anddelayed handovers). If the actual percentage ofdelayed A2-related inter-RAT handovers is greaterthan this parameter value, optimization on thethreshold for inter-RAT event A2 is triggered.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 20

MRO UnnecInterRatHoOptThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold for the inter-RAThandover success rate used to evaluate MRO againstunnecessary inter-RAT handovers. If the inter-RAThandover success rate is greater than or equal to thisparameter value, this type of MRO is triggered.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 95



99

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

MRO UnnecInterRatHoRatioThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold for the percentage ofunnecessary inter-RAT handovers used to evaluateinter-RAT MRO against unnecessary handovers. If thepercentage of unnecessary inter-RAT handovers isgreater than this parameter value, this type of MRO istriggered.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 20

MRO InterFreqA2RollBackThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold of event A2 rollbacktriggered by inter-frequency MRO. If the percentageof too late handovers caused by late inter-frequencymeasurement to the sum of too early handovers andtoo late handovers is less than the threshold, the eventA2 rollback is triggered.GUI Value Range: 0~100Unit: %Actual Value Range: 0~100Default Value: 2

MRO InterFreqA2RollBackPeriod

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the number of MRO periods forlowering the reference signal received power (RSRP)threshold. If the conditions for lowering the RSRPthreshold in inter-frequency A2-related delayedhandovers are met for the consecutive number ofMRO periods specified by this parameter, the RSRPthreshold for triggering inter-frequency event A2 islowered.GUI Value Range: 1~30Unit: NoneActual Value Range: 1~30Default Value: 30

CellMro LocalCellId

LSTCELLMROMODCELLMRO

None None Meaning: Indicates the local ID of the cell. It uniquelyidentifies a cell within an eNodeB.GUI Value Range: 0~255Unit: NoneActual Value Range: 0~255Default Value: None



100

MO Parameter ID

MMLCommand

FeatureID

FeatureName

Description

MRO InterRatStatNumThd

MODMROLSTMRO

LOFD-002005 /TDLOFD-002005


Meaning: Indicates the threshold of the number ofhandovers (including outgoing handover attempts anddelayed handovers) required for enabling optimizationof inter-RAT mobility-related parameters.Optimization of inter-RAT mobility-relatedparameters is started when the number of handoversfrom the local cell to inter-RAT neighboring cellsreaches this threshold.GUI Value Range: 0~10000Unit: NoneActual Value Range: 0~10000Default Value: 1000



101

11 Counters

Table 11-1 Counters

Counter ID Counter Name CounterDescription

Feature ID Feature Name

1526726989 L.IRATHO.E2W.PrepAttOut

Number of inter-RAT handoverattempts from E-UTRAN toWCDMA network

Multi-mode:MRFD-101401GSM: NoneUMTS: NoneLTE:LOFD-001019LOFD-001022LOFD-001033TDLOFD-001019TDLOFD-001022TDLOFD-001033

UL Unified VideoSteering

PS Inter-RATMobility betweenE-UTRAN andUTRANSRVCC to UTRANCS Fallback toUTRANPS Inter-RATMobility betweenE-UTRAN andUTRANSRVCC to UTRANCS Fallback toUTRAN

eRAN TDDMRO Feature Parameter Description 11 Counters


102



1526726991 L.IRATHO.E2W.ExecSuccOut

Number ofsuccessful inter-RAT handoversfrom E-UTRAN toWCDMA network

Multi-mode:MRFD-101401GSM: NoneUMTS: NoneLTE:LOFD-001019LOFD-001022LOFD-001033TDLOFD-001019TDLOFD-001022TDLOFD-001033

UL Unified VideoSteering

PS Inter-RATMobility betweenE-UTRAN andUTRANSRVCC to UTRANCS Fallback toUTRANPS Inter-RATMobility betweenE-UTRAN andUTRANSRVCC to UTRANCS Fallback toUTRAN

1526726992 L.IRATHO.E2G.PrepAttOut

Number of inter-RAT handoverattempts from E-UTRAN toGERAN

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:LOFD-001020LOFD-001023LOFD-001034TDLOFD-001020TDLOFD-001023TDLOFD-001034

PS Inter-RATMobility betweenE-UTRAN andGERANSRVCC to GERANCS Fallback toGERANPS Inter-RATMobility betweenE-UTRAN andGERANSRVCC to GERANCS Fallback toGERAN



103



1526726994 L.IRATHO.E2G.ExecSuccOut

Number ofsuccessful inter-RAT handoversfrom E-UTRAN toGERAN

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:LOFD-001020LOFD-001023LOFD-001034TDLOFD-001020TDLOFD-001023TDLOFD-001034

PS Inter-RATMobility betweenE-UTRAN andGERANSRVCC to GERANCS Fallback toGERANPS Inter-RATMobility betweenE-UTRAN andGERANSRVCC to GERANCS Fallback toGERAN

1526727226 L.IRATHO.E2T.PrepAttOut

Number of inter-RAT HandoverAttempts from E-UTRAN to TD-SCDMA network

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:LOFD-001019LOFD-001022TDLOFD-001019TDLOFD-001022

PS Inter-RATMobility betweenE-UTRAN andUTRANSRVCC to UTRANPS Inter-RATMobility betweenE-UTRAN andUTRANSRVCC to UTRAN

1526727228 L.IRATHO.E2T.ExecSuccOut

Number ofsuccessful inter-RAT handoversfrom E-UTRAN toTD-SCDMAnetwork

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:LOFD-001019LOFD-001022TDLOFD-001019TDLOFD-001022

PS Inter-RATMobility betweenE-UTRAN andUTRANSRVCC to UTRANPS Inter-RATMobility betweenE-UTRAN andUTRANSRVCC to UTRAN

1526727378 L.Traffic.User.Avg Average number ofusers in a cell

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:LBFD-002007TDLBFD-002007

RRC ConnectionManagementRRC ConnectionManagement



104



1526728173 L.HHO.Ncell.PingPongHo

Number of ping-pong handoversbetween twospecific cells

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:LBFD-00201801TDLBFD-00201801LBFD-00201802TDLBFD-00201802LBFD-00201804TDLBFD-00201804LBFD-00201805TDLBFD-00201805

Coverage BasedIntra-frequencyHandoverCoverage BasedIntra-frequencyHandoverCoverage BasedInter-frequencyHandoverCoverage BasedInter-frequencyHandoverDistance BasedInter-frequencyHandoverDistance BasedInter-frequencyHandoverService Based Inter-frequencyHandoverService Based Inter-frequencyHandover

1526728355 L.HHO.NCell.HoToolate

Number of delayedintra-RAThandovers betweentwo specific cells

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:LOFD-002005TDLOFD-002005

Mobility RobustOptimization(MRO)Mobility RobustOptimization(MRO)

1526728356 L.HHO.NCell.HoTooearly

Number ofpremature intra-RAT handoversbetween twospecific cells





105



1526728952 L.HHO.NCell.HoToWrgCell

Number of intra-RAT handovers to awrong cell betweentwo specific cells

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:TDLOFD-002005LOFD-002005


1526728953 L.HHO.NCell.HoToWrgCell.HoSucc

Number ofsuccessful intra-RAT handovers to awrong cell betweentwo specific cells



1526729053 L.HHO.NCell.A2MeasHOTooLate

Number of A2-related delayedintra-RAThandovers



1526733169 L.HHO.NCell.PingPongHo.Consecutive

Number ofconsecutive ping-pong handoversbetween twospecific cells



1526733170 L.HHO.NCell.UeMro.Cio

Number of timesthat the anti-ping-pong-handoverparameter CIO issent in two specificcells based on UE-level MRO





106



1526733171 L.MeasCtrl.InterFreqA3.Coverage.Num.Total

Number of inter-frequencymeasurementconfigurations forevent A3

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:LBFD-00201802TDLBFD-00201802LOFD-002005TDLOFD-002005

Coverage BasedInter-frequencyHandoverCoverage BasedInter-frequencyHandoverMobility RobustOptimization(MRO)Mobility RobustOptimization(MRO)

1526733172 L.MeasCtrl.InterFreqA4A5.Coverage.Num.Total

Number of inter-frequencymeasurementconfigurations forevent A4/A5 sentdue to coverage

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:LBFD-00201802TDLBFD-00201802

Coverage BasedInter-frequencyHandoverCoverage BasedInter-frequencyHandover

1526737680 L.IRATHO.E2U.HoTooLate

Number of delayedEUTRAN-to-UTRAN handovers



1526737681 L.IRATHO.E2G.HoTooLate

Number of delayedEUTRAN-to-GERAN handovers



1526737682 L.IRATHO.E2U.A2MeasHOTooLate

Number of delayedA2-relatedEUTRAN-to-UTRAN handovers





107



1526737683 L.IRATHO.E2G.A2MeasHOTooLate

Number of delayedA2-relatedEUTRAN-to-GERAN handovers



1526737684 L.IRATHO.E2U.Unnecessary.HO

Number ofunnecessaryEUTRAN-to-UTRAN handovers



1526737685 L.IRATHO.E2U.Pingpong.HO

Number of ping-pong EUTRAN-to-UTRAN handovers



1526737686 L.IRATHO.E2U.HoTooEarly

Number ofprematureEUTRAN-to-UTRAN handovers



1526737687 L.IRATHO.E2G.HoTooEarly

Number ofprematureEUTRAN-to-GERAN handovers



1526737784 L.IRATHO.E2G.Unnecessary.HO

Number ofunnecessaryEUTRAN-to-GERAN handovers

Multi-mode: NoneGSM: NoneUMTS: NoneLTE:TDLOFD-002005

Mobility RobustOptimization(MRO)



108



1526741893 L.HHO.PingPongHo

Number of intra-RAT ping-ponghandovers



1526741894 L.HHO.HoToWrgCell

Number of intra-RAT handovers towrong cells



1526741895 L.HHO.HoTooearly Number ofpremature intra-RAT handovers



1526741896 L.HHO.HoToolate Number of delayedintra-RAThandovers





109

12 Glossary

For the acronyms, abbreviations, terms, and definitions, see Glossary.

eRAN TDDMRO Feature Parameter Description 12 Glossary


110

13 Reference Documents

1. 3GPP TS 36.331, "RRC Protocol Specification"2. 3GPP TS 36.300, "E-UTRAN Overall description"3. 3GPP TS 36.423, "X2 Application Protocol"4. 3GPP TS 36.413, "S1 Application Protocol"5. Intra-RAT Mobility Management in Connected Mode Feature Parameter Description6. Inter-RAT Mobility Management in Connected Mode Feature Parameter Description7. ANR Management Feature Parameter Description

eRAN TDDMRO Feature Parameter Description 13 Reference Documents


111