05 Huawei WCDMA Handover Principle and Relevant Parameters

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Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.

WCDMA Handover Principle and Relevant Parameters

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Page1Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.

Foreword

� Why mobile systems need handover?

� It is decided by the characters of mobile system:

� The mobility of UE

� The mobile system is composed by cells which the coverage

ability is limited.

� Providing the continuous service in mobile system is the basic

element in QoS.

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Objectives

� Upon completion of this course, you will be able to:

� Know the basic definitions of Handover

� The algorithms of handover decision

� The handover flow

� The parameters of handover

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Contents

1. Introduction of Handover

2. Measurement of Handover

3. The Basic Handovers

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The Purpose of Handover

� Providing the continuous service in mobile system is the

basic element in QoS

� The load balance: sharing the resource

� The hierarchy divided by speed and service: high efficiency

of using resource

� Handover is a basic function of a cellular mobile network. The purpose of handover is

to ensure that a UE in CELL_DCH state is served continuously when it moves.

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The Basic Concepts of Handover

� Active Set

� Monitored Set

� Detected set

� Radio Link (RL)

� Radio Link Set

(RLS)

� maximum ratio combination

� selection combination

� The soft handover gain

� CPICH

� Active set : Cells, which belong to the active set. User information is sent from all these cells.

In FDD, the cells in the active set are involved in soft handover. In TDD the active set always

comprises one cell only. The UE shall only consider active set cells included in the variable

CELL_INFO_LIST for measurement; i.e. active set cells not included in the CELL_INFO_LIST

shall not be considered in any event evaluation and measurement reporting.

� Monitored set :Cells, which are not included in the active set, but are included in the

CELL_INFO_LIST belong to the monitored set.

� Detected set : Cells detected by the UE, which are neither in the CELL_INFO_LIST nor in the

active set belong to the detected set. Reporting of measurements of the detected set is only

applicable to intra-frequency measurements made by UEs in CELL_DCH state.

� RL: Radio link between NodeB and UE.

� RLS: Radio link set. The RLs from same NodeB.

� Combination way: For soft handover, the uplink signals are combined in RNC. The RNC will

select one best signal to process. We call this selective combination. For softer handover, the

uplink signals are combined in the RAKE receiver of NodeB. It is maximum ratio combination.

� Soft handover gain: We have introduced in Coverage Planning.

� CPICH: Common Pilot Channel. UE measure the signal strength of CPICH for handover

decision.

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The Categories of Handover

� According to the signaling characters

� Soft handover (softer handover)

� Hard handover

� According to the properties of source cell and target cell:

� Intra-frequency handover

� Inter-frequency handover

� Inter-RAT handover (UMTS ↔ GSM/GPRS)

� According to the purpose of handover:

� Based on Coverage

� Based on Noncoverage

� The unique signaling of soft handover is Active Set Update, and the unique signaling

of hard handover is Physical Channel Reconfiguration.

� Soft handover include soft handover and softer handover. It is depended on if the two

(or three) RLs belong to one NodeB.

� The handover based on load is load control algorithm.

� The handover based on mobility of UE is for HCS handover.

� The handover based on service: for example, the handover between R99 and

HSDPA.

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The Characters of Different Handover

� Comparison between soft handover and hard handover:

Can be happened in Intra-

frequency cells or Inter-frequency

cells

Only happened

between Intra-

frequency cells

The frequencies of cells

YesNoInterruption during

handover

OneSeveral The number of RLs in

active set after handover

Hard HandoverHard HandoverSoft HandoverSoft HandoverItemItem

� The maximum number of RL is 3. This value can be changed. But this function need

the UE to support. Normally, the active set supported by UE is fixed 3 and can not be

changed.

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The Characters of Different Handover

Signal combined in UE by

maximum ratio combination

Signal combined in

UE by maximum ratio

combination

DL combination

Signal combined in NodeB by

maximum ratio combination

Signal combined in

RNC by selective

combination

UL combination

Softer HandoverSofter HandoverSoft HandoverSoft HandoverItemItem

� Comparison between soft handover and softer handover :

� During softer handover, the uplink signaling are combined in NodeB by maximum ratio combination, but during soft handover they are combined in RNC by selective combination

� Compare to later one, the maximum ratio combination can get more gain. So the performance of maximum ratio combination is better

� Since softer handover is completed in NodeB, it do not consume transport resource of Iub

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Soft Handover

RNC

NodeB 2NodeB 1

Cell A Cell B

� It is soft handover. During the handover, two radio links are connected with UE, and

data in each RL are same. So the UE can combine the data in RAKE receiver. But the

control part are different for downlink.

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Softer Handover

RNC

NodeB

Cell BCell A

� It is softer handover. The cells in active set belong to one NodeB. The NodeB use the

RAKE receiver to combine the data in HULP board. Then send the data to WFMR

board in RNC.

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Hard Handover

RNC

NodeB 2NodeB 1

Cell A Cell B

� It is hard handover. The UE disconnect the original radio link, then connect to the

target cell. It happened in intra-frequency, inter-frequency and inter-RAT.

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Three Steps of Handover

Decision

Execution

Measurement

The following figure shows handover procedure (measurement quality set to PCPICH Ec/No)

Decision phase

Execution phase

Measurement phase

Yes

NoAre handover criteria satisfied?

Perform a handover and update relative parameters

Measure the CPICH Ec/N0 of the serving cell andits neighboring cells as well as the relative timedifference between the cells

� In the measurement phase, the UE takes measurement according to the

MEASUREMENT CONTROL message received from the RNC. The UE sends related

measurement reports to the RNC according to the rules defined in the

MEASUREMENT CONTROL message when the event triggering conditions are met.

� After receiving the intra-frequency measurement report from the UE, the RNC decides

whether to go to the execution phase, depending on the information in the report.

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Contents




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Contents


2.1 Measurement Control and Measurement Report

2.2 Measurement Phase

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Measurement Control, normal case

UE UTRAN

MEASUREMENT CONTROL

Measurement Control

� If the UE setup a RRC connection or trigger the 1D event, the UTRAN will send the measurement control to UE. The measurement control include the algorithm of measurement and handover, for example, the intra-frequency handover criteria, and how to report.

� The latter message includes the following measurement control information:

� 1. Measurement identity: A reference number that should be used by the UTRAN when setting up, modifying or releasing the measurement and by the UE in the measurement report.

� 2. Measurement command: One out of three different measurement commands.

� -Setup: Setup a new measurement.

� -Modify: Modify a previously defined measurement, e.g. to change the reporting criteria.

� -Release: Stop a measurement and clear all information in the UE that are related to that measurement.

� 3. Measurement type: One of the types listed above describing what the UE shall measure. Presence or absence of the following control information depends on the measurement type.

� 4. Measurement objects: The objects the UE shall measure, and corresponding object information.

� 5. Measurement quantity: The quantity the UE shall measure. This also includes the filtering of the measurements.

� 6. Reporting quantities: The quantities the UE shall include in the report in addition to the quantities that are mandatory to report for the specific event.

� 7. Measurement reporting criteria: The triggering of the measurement report, e.g. periodical or event-triggered reporting.

� 8. Measurement Validity: Defines in which UE states the measurement is valid.

� 9. Measurement reporting mode: This specifies whether the UE shall transmit the measurement report using AM or UM RLC.

� 10. Additional measurement identities: A list of references to other measurements. When this measurement triggers a measurement report, the UE shall also include the reporting quantities for the measurements referenced by the additional measurement identities.

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Measurement Control, normal case

UE UTRAN

MEASUREMENT REPORT

Measurement Report

� The purpose of the measurement reporting procedure is to transfer

measurement results from the UE to UTRAN.

� Based on the algorithm in measurement control, the UE will measure the

signal strength and check if it meet the requirement of all event. If it meet the

requirement of any event, UE will send the measurement report to UTRAN to

trigger the handover. The most important information in the measurement are

the PSC and the CPICH Ec/No of the target cell, and the triggered event.

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Contents


2.1 Measurement Control and Measurement Report

2.2 Measurement Phase

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Measurement Model

Layer 1filtering

Layer 3filtering

Evaluationof reporting

criteria

A DB C

C'

parameters parameters

� A is measurement value at the physical layer

� B is the measurement value after layer 1 filtering at physical layer. The value goes from the physical layer to high layer

� C is measurement after processing in the layer3 filter

� C’ is another measurement value

� D is measurement report information sent on the radio interface or Iub interface

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Measurement Quantity

� Ec/No

� CPICH signal quality

� RSCP

� CPICH signal level

� RSSI

� GSM cell signal level

The measurement quantity of intra-frequency or inter-frequency measurement can be Ec/No (dB) or RSCP (dBm) of a common pilot channel .

For inter-RAT measurement ,GSM cell RSSI is used.

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Measurement Quantity Configuration� IntraFreqMeasQuantity

� Parameter name: Intra-frequency measure quantity

� The default value of this parameter is Ec/No

� InterFreqMeasQuantity

� Parameter name: Inter-frequency measure quantity

� The default value of this parameter is “Both”

� MeasQuantityOf3A

� Parameter name: 3A Measure Quantity

� The default value of this parameter is RSCP

�IntraFreqMeasQuantity

�Parameter name: Intra-frequency measurement quantity

�Value range: CPICH_Ec/No, CPICH_RSCP .

�Content: Measurement value used in intrafrequency measurement .

�The recommended value of this parameter is CPICH_EC/NO

�Set this parameter through SET INTRAFREQHO, query it through LST INTRAFREQHO.

�InterFreqMeasQuantity

�Parameter name: Inter-frequency measurement quantity

�Value range: CPICH_Ec/No, CPICH_RSCP, BOTH .

�Content: Measurement quantity used in coverage-based inter-frequency measurement .

�The recommended value of this parameter is BOTH.

�Set this parameter through SET INTERFREQHOCOV, query it through LST INTERFREQHOCOV.

�MeasQuantityOf3A

�Parameter name: 3A Measure Quantity

�Value range: CPICH_Ec/No, CPICH_RSCP.

�Content: Measurement quantity used in coverage-based inter-RAT measurement .

�The recommended value of this parameter is CPICH_RSCP.

�Set this parameter through SET INTERRATHOCOV, query it through SET INTERRATHOCOV.

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Layer 3 filtering

� Fn is the new measurement value after filtering.

� Fn-1 is the last measurement value after filtering.

� Mn is the latest measurement value from the physical layer.

� a = 1/2(k/2) (k is set to Intra-freq meas L3 filter coeff)

nnn MaFaF ⋅+⋅−= −1)1(

Where:

The greater this parameter is ,the stronger the smoothing effect on the signal will be , and the stronger the fast fading resistance capability will be , but the weaker the tracing capability of the signal change will be.

� When k = 0, that is, a is set to 1, no layer 3 filtering is performed.

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Layer 3 filtering coefficient� FilterCoef

� Parameter name: Intra-frequency measurement filter coefficient

� The default value of this parameter is D3

� InterFreqFilterCoef

� Parameter name: Inter-frequency measure filter coefficient


� InterRATFilterCoef

� Parameter name: Inter-RAT filter coefficient


�FilterCoef

�Parameter name: Intra-frequency measurement filter coefficient

�Value range: 0~19.

�Content: L3 filtering coefficient for intra-frequency measurement. The greater this parameter is, the greater the smoothing effect and the higher the anti fast fading capability, but the lower the signal change tracing capability.

�The recommended value of this parameter is 3


�InterFreqFilterCoef

�Parameter name: Inter-frequency measurement filter coefficient





�InterRATFilterCoef

�Parameter name: Inter-RAT measurement filter coefficient




�Set this parameter through SET INTERRATHOCOV, query it through LST INTERRATHOCOV.

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Measurement Report Mode

� Periodic Report

� Event Trigger Report

� Event to Periodic Report

According to the Measurement Control , UE will report the measurement results to UTRAN by event trigger report or periodic report.

If the UE report a measurement report triggered by Event ,the UE will wait for response from UTRAN, if there is no any response after a specific period, to avoid measurement report loss, the event reporting can be turned to periodical report.

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Contents




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Contents


3.1 Soft Handover

3.2 Intra-frequency Hard Handover

3.3 Inter-frequency Hard Handover

3.4 Inter-RAT Hard Handover

3.5 Blind Handover

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Contents


3.1 Soft Handover




3.5 Blind Handover

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Brief Introduction of Soft Handover

� Characters of Soft Handover

� During handover, UE has several RLs with different cells

� The handover among different cells which are in same RLS can be

softer handover

� Signals from each RL will be combined in UL and DL.

� Soft handover:

selective combination in uplink

Maximum ratio combination in downlink

� Softer handover

Maximum ratio combination in uplink and downlink

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Brief Introduction of Soft Handover

� Advantages

� Soft handover gain

� Decrease the possibility of call drop

� Disadvantages

� More resource needed in downlink

� it way cause side-effect

� Advantages

Because of the signal combination, the combination gain can overcome some of the path

loss

During the handover, UE has several RLs with the network, call drop caused by ping-

pong handover can be avoided

� Disadvantages

Soft handover will occupy more resource ,such as CE, Iub transmission, especially for

the code resources for BE service

When the downlink power from different cells are not balanced, it will cause side-effect in

downlink.

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Measurement of Soft Handover

� Measurement quantity

� CPICH RSCP

� CPICH Ec/No

� Reporting mode

� Periodic reporting

� Event trigger reporting

� Event trigger reporting to Periodic reporting

� Event type

� 1A,1B,1C,1D,1F

Normally, the soft handovers are triggered by 1A,1B,1C events in the Measurement

report signaling, UTRAN will make decisions according to these events

1D event will trigger new measurement control.

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Soft Handover Measurement Events

Event of the change of the best cell1D

A non-active PCPICH becomes better than an active PCPICH. This indicates that

the quality of a cell is close to the quality of the best cell. In addition ,the number of

cells in the active set has reached the maximum value. The cell replaces the worst

cell in the active set ; thus achieving a higher combined gain

1C

The PCPICH quality of the cells in the active set leaves the reporting range. This

indicates that quality of a cell is much worse than the quality of the best cell. The

cell should not stay in the active set

1B

The PCPICH quality of the cells in the monitored set enters the reporting range .

This indicates that the quality of a cell is close to the quality of the best cell . A

relative high combined gain can be achieved when the cell is added to the active

set

1A

DescriptionDescriptionEventEvent

Actually ,we can consider Events are the suggestions from the UE:

1A means UE suggests to add a radio link,

1B means UE suggests to remove a radio link,

1C means UE suggests to exchange a radio link

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The Trigger Algorithm of 1A Event

),2/(10)1(1010 111

aaBest

N

iiNewNew HRLogMWMLogWCIOLogM

A

−−⋅⋅−+

⋅⋅≥+⋅ ∑

=

� Event 1A is triggered on the basis of the following formula

� Mnew is the measurement value of the cell in the reporting range

� CIOnew is cell individual offset of the cell in the reporting range . It is set for the neighboring cell

� W is the weight value

� Mi is the measurement value of the cell in the active set

� NA is the number of cells in the current active set

� Mbest is the measurement value of the best cell in the active set

� R1a is the reporting range or relative threshold of soft handover. The threshold parameters of CS and PS service are CS service 1A event relative threshold , PS service 1A event relative threshold respectively

� H1a is 1A hysteresis , the hysteresis value of event 1A

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Example of 1A Event

A: signal curve of the best cell in the active set A: signal curve of the best cell in the active set

B: signal curve of a cell in the monitoring set B: signal curve of a cell in the monitoring set

C: The 1A curveC: The 1A curve

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Key parameters of 1A Event

� INTRARELTHDFOR1ACS

� Parameter name: CS service 1A event relative threshold

� The default value of this parameter is 6 ( 3dB )

� INTRARELTHDFOR1APS

� Parameter name: PS service 1A event relative threshold


�INTRARELTHDFOR1ACS

�Parameter name: CS service 1A event relative threshold

�Value range: 0~14.5; step: 0.5

�Content: The CS service relative threshold of the event 1A. It is easier to trigger event 1A if the value increases. It is harder to trigger event 1A if the value decreases.

�The recommended value of this parameter is 6 (3dB)


�INTRARELTHDFOR1ACS

�Parameter name: PS service 1A event relative threshold


�Content: The PS service relative threshold of the event 1A. It is easier to trigger event 1A if the value increases. It is harder to trigger event 1A if the value decreases.



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Key parameters of 1A Event� HYSTFOR1A

� Parameter name: 1A event hysteresis

� The default value of this parameter is 0( 0dB )

� TRIGTIME1A

� Parameter name: 1A event trigger delay time

� The default value of this parameter is D320 ( 320ms )

�HYSTFOR1A

�Parameter name: 1A event hysteresis

�Value range: 0~7.5dB; step: 0.5

�Content: The hysteresis value of the event 1A. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.

�The recommended value of this parameter is 0 ( 0dB )


�TRIGTIME1A

�Parameter name: 1A event trigger delay time

�Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

�Content: The trigger delay time of the event 1A. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.

�The recommended value of this parameter is D320 ( 320ms )


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The Trigger Algorithm of 1B Event

� Event 1B is triggered on the basis of the following formula

),2/(10)1(1010 111

bbBest

N

iiOldOld HRLogMWMLogWCIOLogM

A

+−⋅⋅−+

⋅⋅≤+⋅ ∑

=

� Mold is the measurement value of the cell that becomes worse

� CIOold is cell individual offset of the cell in the reporting range . It is set for the neighboring cell

� W is the weight value

� Mi is the measurement value of the cell in the active set

� NA is the number of cells in the current active set

� Mbest is the measurement value of the best cell in the active set

� R1b is the reporting range or relative threshold of soft handover. The threshold parameters of CS and PS service are CS service 1B event relative threshold , PS service 1B event relative threshold respectively

� H1b is 1B hysteresis , the hysteresis value of event 1B

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Example of 1B Event

A: signal curve of the best cell in the active set A: signal curve of the best cell in the active set

B: signal curve of a cell in the monitoring set B: signal curve of a cell in the monitoring set

C: The 1B curveC: The 1B curve

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Key parameters of 1B Event� INTRARELTHDFOR1BCS

� Parameter name: CS service 1B event relative threshold


� INTRARELTHDFOR1BPS

� Parameter name: PS service 1B event relative threshold


�INTRARELTHDFOR1BCS

�Parameter name: CS service 1B event relative threshold


�Content: The CS service relative threshold of the event 1B. It is easier to trigger event 1B if the value decreases. It is harder to trigger event 1B if the value increases.



�INTRARELTHDFOR1BCS

�Parameter name: PS service 1B event relative threshold


�Content: The PS service relative threshold of the event 1B. It is easier to trigger event 1B if the value increases. It is harder to trigger event 1B if the value decreases.



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Key parameters of 1B Event� HYSTFOR1B

� Parameter name: 1B event hysteresis


� TRIGTIME1B

� Parameter name: 1B event trigger delay time


�HYSTFOR1B

�Parameter name: 1B event hysteresis


�Content: The hysteresis value of the event 1B. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.



�TRIGTIME1B

�Parameter name: 1B event trigger delay time

�Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

�Content: The trigger delay time of the event 1B. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.



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The Trigger Algorithm of 1C Event

� Event 1C is triggered on the basis of the following formula

,2/1010 1cInASInASNewNew HCIOLogMCIOLogM ++⋅≥+⋅

� Mnew is the measurement value of the cell in the reporting range

� CIOnew is cell individual offset of the cell in the reporting range . It is set for the neighboring cell

� M inAS is the measurement value of the worst cell in the active set

� CIOInAS is cell individual offset of the worst cell in the active set

� H1c is 1C hysteresis , the hysteresis value of event 1C

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Example of 1C Event

A: signal curve of the best cell in the active set

B: signal curve of a cell in the active set

C: signal curve of the worst cell in the active set

D: signal curve of a cell in the monitoring set

E: The 1C curve

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Key parameters of 1C Event� HYSTFOR1C

� Parameter name: 1C event hysteresis


� TRIGTIME1C

� Parameter name: 1C event trigger delay time


�HYSTFOR1C

�Parameter name: 1C event hysteresis


�Content: The hysteresis value of the event 1C. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.



�TRIGTIME1C

�Parameter name: 1C event trigger delay time

�Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

�Content: The trigger delay time of the event 1C. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.



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The Trigger Algorithm of 1D Event

� Event 1D is triggered on the basis of the following formula

,2/1010 1cInASNew HLogMLogM +⋅≥⋅

� MNotbest is the measurement value of a cell that is not best cell

� M inAS is the measurement value of the worst cell in the active set

� H1d is 1D hysteresis , the hysteresis value of event 1D

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Example of 1D Event

A: signal curve of the best cell in the active set

B: signal curve of a cell in the active set or moni toring set

C: Th1D curve

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Key parameters of 1D Event� HYSTFOR1D

� Parameter name: 1D event hysteresis


� TRIGTIME1D

� Parameter name: 1D event trigger delay time


�HYSTFOR1D

�Parameter name: 1D event hysteresis


�Content: The hysteresis value of the event 1D. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.



�TRIGTIME1D

�Parameter name: 1D event trigger delay time

�Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

�Content: The trigger delay time of the event 1D. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.



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Other key parameters for SHO� Weight

� Parameter name: Weighted factor

� The default value of this parameter is 0

� SHOQualmin

� Parameter name: Min quality THD for SHO

� The default value of this parameter is -24(-24 dB)

� CELLINDIVIDALOFFSET

� Parameter name: Cell offset


�Weight

�Parameter name: Weighted factor

�Value range: 0~2

�Content: This parameter is used to define the soft handover relative threshold based on the measured value of each cell in the active set. The greater this parameter is set, the higher the soft handover relative threshold. When this parameter is set as 0, the soft handover relative threshold is only for the best cell in the active set.

�The recommended value of this parameter is 0.


�SHOQualmin

�Parameter name: Min quality THD for SHO

�Value range: -24~0;

�Content: minimum quality threshold for soft handover .

�The recommended value of this parameter is -24 (-24dB)


�CELLINDIVIDALOFFSET

�Parameter name: Cell offset

�Value range: -10~10 dB;

�Content: Offset of cell CPICH measurement value. The offset is added to the measurement quantity before the UE evaluates if an event has occurred. In handover algorithms, this parameter is used for moving the border of a cell.


�Set this parameter through ADD INTRAFREQNCELL, query it through LST INTRAFREQNCELL.

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Contents


3.1 Soft Handover




3.5 Blind Handover

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Brief Introduction of Intra-Frequency Handover

� Characters of Intra-Frequency Handover

� During handover, UE has only one RL with one cell

� Switch off the RL with the original cell, then setup the RL with target

cell

� The frequency of source cell and target cell are same

� In some cases ,UE want to take soft handover according to the intra-frequency

measurement, but RNC don’t allow the UE to take this soft handover cause there is

no IUR interface between 2 RNCs or the service rate is higher than a threshold, then

the UE has to ask for hard handover based on the measurement.

� During the intra-frequency hard handover, the RNC will ask the UE to switch off the

RL with the original cell and setup the RL with the target cell, so there is a gap during

this procedure.

� Intra-Frequency Handover is always triggered by 1D event.

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Brief Introduction of Intra-Frequency Handover

� Advantages

� Enhance the usage efficiency of the OVSF code and hardware

� Disadvantages

� High call drop possibility because of the intra-frequency

interference

� Cause there is only 1 RL for the UE, OVSF code resources ,CE resources DL tx

power resources and IUB resources can be saved

� During the hard handover, the frequency of the original cell and target cell are the

same, so when the UE want to setup the RL with the target cell, the original cell will

cause DL interference to the UE.

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Key parameters of Intra-frequency Hard handover

� BEBITRATETHD

� Parameter name: BE service handover rate threshold

� The default value of this parameter is 384k

� The Parameters about 1D Event

� Time to trigger

� Hysteresis

�BEBITRATETHD

�Parameter name: BE service handover rate threshold

�Value range: 8k, 16k, 32k, 64k, 128k, 144k, 256k, 384k

�Content: The bit rate threshold used to determine whether to perform soft handover for the Best Effort (BE) service on DCH. When the maximum bit rate of the BE service is lower than or equal to this threshold, the system will perform soft handover for this user to guarantee the service quality. If the maximum bit rate of the BEservice is higher than the threshold, the system will perform intra-frequency hard handover for this user to avoid the too great effect of soft handover on the system capacity. .

�The recommended value of this parameter is 384k.

�Set this parameter through SET HOCOMM, query it through SET HOCOMM.

Course Name


N-51


Contents


3.1 Soft Handover




3.5 Blind Handover

Course Name


N-52


Brief Introduction of Inter-Frequency Handover

� Characters of Soft Handover

� The frequency of original cell and source cell are different

� There is only one RL for the UE

� The compressed mode is needed

� If the frequency of the original cell and target cell are different, the soft handover is

impossible.

� In a WCDMA FDD system, the UE in CELL_DCH state sends and receives signals

continuously in uplink and downlink channels. If the UE in this case needs to measure

the pilot signal strength of an inter-frequency WCDMA or GSM cell, and it has only

mono-frequency receiver, the UE must use the compressed mode technique.

Course Name


N-53


Compressed Mode

� Purpose

� Measure the inter-frequency cell or Inter-RAT cell under FDD mode

� Categories

� Downlink compressed mode

� Uplink compressed mode

� Realization Methods

� SF/2

� Higher layer scheduling

� In order to realize inter-frequency and inter-RAT measurement , WCDMA system

introduces compressed mode .

� In DL, during compressed mode ,UE receiver can test signal from other frequency. In

order to avoid the effect cause by UE transmitter, compress mode is also used in UL.

� The compressed mode includes two types, spreading factor reduction (SF/2) and high

layer approaches. The usage of type of compressed mode is decided by the RNC

automatically, according to spreading factor used in uplink or downlink.

Course Name


N-54


Measurement of Inter-frequency Handover


� CPICH RSCP

� CPICH Ec/No

� Reporting mode

� Periodic reporting

� Event trigger reporting

� Event trigger reporting to Periodic reporting

� Event type

� 2B,2C,2D,2F

� Inter-frequency handover is also based on measurement. Similar with soft handover,

measurement quantity include CPICH RSCP or Ec/No

� UE can report the measurement result when event triggered ,then RNC performs

handover decision. Or the UE periodically reports the inter-frequency measurement

report, and the RNC decides the handover after evaluation.

Course Name


N-55


Inter-frequency Handover Measurement Events

The estimated quality of a inter-frequency neighbor cell is higher than the

preset threshold

2C

When the current signal frequency is lower than the preset threshold and

the signal quality of an inter-frequency neighbouring cell is higher than

the preset threshold , the UTRAN trigger an inter-frequency handover

based on coverage

2B

When the current signal quality is higher than the preset threshold, the

UTRAN disables the compressed mode and stops inter-frequency

measurement

2F

When the current signal quality is lower than the preset threshold , the

UTRAN enables the compressed mode and starts inter-frequency

measurement

2D

DescriptionEvent

� During the movement, UE can detect the severing cell signal is getting worse, then

the UE will report a 2D event to trigger compress mode, and then the UE can

measure the signals of inter-frequency neighbors. During the measurement period, if

the serving cell signal recovers, UE will report a 2F event to stop compress mode,

that is to stop the inter-frequency measurement.

� During the compress mode ,UE can measure the inter-frequency cell signal, and 2B

and 2C event may be triggered.

Course Name


N-56



� Event 2D is triggered on the basis of the following formula

2/22 ddUsedUsed HTQ −≤

� QUsed is the measured quality of the cell that uses the current frequency.

� TUsed2d is the absolute quality threshold of the cell that uses the current

frequency. Based on the service type (CS or PS) and measurement quantity

(CPICH Ec/No or RSCP), this threshold can be configured as Inter-freq CS

measure start Ec/No THD, Inter-freq PS measure start Ec/No THD, Inter-freq

CS measure start RSCP THD, Inter-freq PS measure start RSCP THD

respectively.

� H2d is the event 2D hysteresis value 2D hysteresis.

� After the conditions of Event 2D are fulfilled and maintained until the 2D event

trigger delay time is reached, the UE reports the Event 2D measurement

report message.

Course Name


N-57


Key parameters of of 2D Event

� InterFreqCSThd2DEcN0

� Parameter name: Inter-freq CS measure start Ec/No THD

� The default value of this parameter is -14 dB

� InterFreqPSThd2DEcN0

� Parameter name: Inter-freq PS measure start Ec/No THD


�InterFreqCSThd2DEcN0

�Parameter name: Inter-freq CS measure start Ec/No THD

�Value range: -24~0dB;

�Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.

�The recommended value of this parameter is -14dB


�InterFreqPSThd2DEcN0

�Parameter name: Inter-freq PS measure start Ec/No THD


�Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.



Course Name


N-58


Key parameters of of 2D Event

� InterFreqCSThd2DRSCP

� Parameter name: Inter-freq CS measure start RSCP THD

� The default value of this parameter is -95 dBm

� InterFreqPSThd2DRSCP

� Parameter name: Inter-freq PS measure start RSCP THD


�InterFreqCSThd2DRSCP

�Parameter name: Inter-freq CS measure start RSCP THD

�Value range: -115~-25dBm;

�Content: For CS domain services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.



�InterFreqPSThd2DRSCP

�Parameter name: Inter-freq PS measure start RSCP THD


�Content: For PS domain services, whenRSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.



Course Name


N-59


Key parameters of 2D Event� HYSTFOR2D

� Parameter name: 2D event hysteresis


� TRIGTIME2D



�HYSTFOR2D

�Parameter name: 2D event hysteresis

�Value range: 0 to 14.5 dB, step: 0.5

�Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2D might not be triggered in time.



�TRIGTIME2D

�Parameter name: 2D event trigger delay time

�Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

�Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2D to measurement signal change.



Course Name


N-60


The Trigger Algorithm of 2F Event

� Event 2F is triggered on the basis of the following formula

2/22 ffUsedUsed HTQ +≥

�� QQUsedUsed is the measured quality of the cell that uses the current frequis the measured quality of the cell that uses the current frequency.ency.

�� TTUsed2FUsed2F is the absolute quality threshold of the cell that uses the curis the absolute quality threshold of the cell that uses the current rent

frequency. Based on the service type (CS or PS) and measurement frequency. Based on the service type (CS or PS) and measurement quantity quantity

(CPICH (CPICH EcEc/No or RSCP), this threshold can be configured as Inter/No or RSCP), this threshold can be configured as Inter--freq CS freq CS

measure start measure start EcEc/No THD, Inter/No THD, Inter--freq PS measure start freq PS measure start EcEc/No THD, Inter/No THD, Inter--freq freq

CS measure start RSCP THD, InterCS measure start RSCP THD, Inter--freq PS measure start RSCP THD freq PS measure start RSCP THD

respectively.respectively.

�� HH2F2F is the event 2F is the event 2F hysteresishysteresis value 2F value 2F hysteresishysteresis..

�� After the conditions of Event 2F are fulfilled and maintained unAfter the conditions of Event 2F are fulfilled and maintained until the 2F event til the 2F event

trigger delay time is reached, the UE reports the Event 2F measutrigger delay time is reached, the UE reports the Event 2F measurement report rement report

message.message.

Course Name


N-61


Key parameters of 2F Event� InterFreqCSThd2FEcN0

� Parameter name: Inter-freq CS measure stop Ec/No THD


� InterFreqPSThd2FEcN0

� Parameter name: Inter-freq PS measure stop Ec/No THD


�InterFreqCSThd2FEcN0

�Parameter name: Inter-freq CS measure stop Ec/No THD

�Value range: -24~-0dB;

�Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivatecompressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter. .



�InterFreqPSThd2FEcN0

�Parameter name: Inter-freq PS measure start Ec/No THD


�Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivatecompressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.



Course Name


N-62


Key parameters of 2F Event

� InterFreqCSThd2FRSCP

� Parameter name: Inter-freq CS measure stop RSCP THD


� InterFreqPSThd2FRSCP

� Parameter name: Inter-freq PS measure stop RSCP THD


�InterFreqCSThd2FRSCP

�Parameter name: Inter-freq CS measure stop RSCP THD


�Content: For CS domain services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivatecompressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter. .

�The recommended value of this parameter is -92dBm


�InterFreqPSThd2FRSCP


�Value range: -115~-25dB;

�Content: For PS domain services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivatecompressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.



Course Name


N-63


Key parameters of 2F Event

� HYSTFOR2F

� Parameter name: 2F event hysteresis


� TRIGTIME2F

� Parameter name: 2F event trigger delay time


�HYSTFOR2F

�Parameter name: 2F event hysteresis


�Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2F might not be triggered in time.



�TRIGTIME2F

�Parameter name: 2F event trigger delay time

�Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

�Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2F to measurement signal change.



Course Name


N-64


The Trigger Algorithm of 2B Event

� Event 2B is triggered on the basis of the following formula

2/22 bbusedNonusedNon HTQ +≥ 2/22 bbUsedUsed HTQ −≤, and

� QNoused is the measured quality of the cell that uses other frequency.

� TNoused2b is the absolute quality threshold of the cell that uses other frequency.

Based on the service type (CS or PS) and measurement quantity (CPICH

Ec/No or RSCP), this threshold can be configured as Inter-freq CS target

frequency trigger Ec/No THD, Inter-freq PS target frequency trigger Ec/No

THD, Inter-freq CS target frequency trigger RSCP THD, And Inter-freq PS

target frequency trigger RSCP THD respectively.

� QUsed is the measured quality of the cell that uses the current frequency.

� TUsed2d is the absolute quality threshold of the cell that uses the current

frequency. Based on the service type (CS or PS) and measurement quantity

(CPICH Ec/No or RSCP), this threshold can be configured as Inter-freq CS

measure start Ec/No THD, Inter-freq PS measure start Ec/No THD, Inter-freq

CS measure start RSCP THD, Inter-freq PS measure start RSCP THD

respectively.

� H2b is the event 2B hysteresis value 2B hysteresis.

Course Name


N-65


Key parameters of 2B Event

� InterFreqCovHOCSThdEcN0

� Parameter name: Inter-freq CS target frequency trigger Ec/No THD


� InterFreqCovHOPSThdEcN0

� Parameter name: Inter-freq PS target frequency trigger Ec/No THD


�InterFreqCovHOCSThdEcN0

�Parameter name: Inter-freq CS target frequency trigger Ec/No THD


�Content: For CS domain services,- If the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 2B. The quality of the target frequency being higher than this threshold is necessary to the triggering of the event 2B.- If the value of [Inter-frequency measure report mode] is PERIODICAL_REPORTING, this parameter is used to evaluate inter-frequency handovers at the RNC.



�InterFreqCovHOPSThdEcN0

�Parameter name: Inter-freq PS target frequency trigger Ec/No THD


�Content: - If the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 2B. The quality of the target frequency being higher than this threshold is necessary to the triggering of the event 2B.- If the value of [Inter-frequency measure report mode] is PERIODICAL_REPORTING, this parameter is used to evaluate inter-frequency handovers at the RNC.



Course Name


N-66



� InterFreqCovHOCSThdRSCP

� Parameter name: Inter-freq CS target frequency trigger RSCP THD


� InterFreqCovHOPSThdRSCP

� Parameter name: Inter-freq PS target frequency trigger RSCP THD


�InterFreqCovHOCSThdRSCP

�Parameter name: Inter-freq CS target frequency trigger RSCP THD


�Content: For CS domain services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.



�InterFreqPSThd2DRSCP



�Content: For PS domain services, whenRSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.



Course Name


N-67



� IFHOUsedFreqCSThdEcN0

� Parameter name: Inter-freq CS Used frequency trigger Ec/No THD

� The default value of this parameter is -12dB

� IFHOUsedFreqPSThdEcN0

� Parameter name: Inter-freq PS Used frequency trigger Ec/No THD


�IFHOUsedFreqCSThdEcN0

�Parameter name: Inter-freq CS Used frequency trigger Ec/No THD

�Value range: -24~0 dB

�Content: For CS domain services, if the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set themeasurement control on the event 2B. The quality of the used frequency being lower than this threshold is necessary to the triggering of the event 2B .

�The recommended value of this parameter is -12 dB


�IFHOUsedFreqPSThdEcN0

�Parameter name: Inter-freq PS Used frequency trigger Ec/No THD

�Value range: -24~0 dB

�Content: For PS domain services, if the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set themeasurement control on the event 2B. The quality of the used frequency being lower than this threshold is necessary to the triggering of the event 2B .

�The recommended value of this parameter is -12 dB


Course Name


N-68



� IFHOUsedFreqCSThdRSCP

� Parameter name: Inter-freq CS Used frequency trigger RSCP THD

� The default value of this parameter is -92dBm

� IFHOUsedFreqPSThdRSCP

� Parameter name: Inter-freq PS Used frequency trigger RSCP THD


�IFHOUsedFreqCSThdRSCP

�Parameter name: Inter-freq CS Used frequency trigger RSCP THD

�Value range: -115~-25 dBm

�Content: For CS domain services, if the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set themeasurement control on the event 2B. The quality of the used frequency being lower than this threshold is necessary to the triggering of the event 2B .

�The recommended value of this parameter is -92 dBm


�IFHOUsedFreqPSThdRSCP

�Parameter name: Inter-freq PS Used frequency trigger RSCP THD

�Value range: -115~-25 dBm

�Content: For PS domain services, if the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set themeasurement control on the event 2B. The quality of the used frequency being lower than this threshold is necessary to the triggering of the event 2B .

�The recommended value of this parameter is -92 dBm


Course Name


N-69


Key parameters of 2B Event� HYSTFOR2B

� Parameter name: 2B event hysteresis


� TRIGTIME2B

� Parameter name: 2B event trigger delay time


�HYSTFOR2B

�Parameter name: 2B event hysteresis


�The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2B might not be triggered in time.



�TRIGTIME2B

�Parameter name: 2B event trigger delay time

�Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

�Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2B to measurement signal change.

�The recommended value of this parameter is D0 (0ms )


Course Name


N-70



� Event 2C is triggered on the basis of the following formula

2/22 ccusedNonusedNon HTQ +≥

� QNoused is the measured quality of the cell that uses other frequency.

� TNoused is the absolute quality threshold of the cell that uses other frequency.

Inter-freq measure target frequency trigger Ec/No THD.

� H2c is the event 2C hysteresis value 2C hysteresis.

Course Name


N-71


Key parameters of 2C Event

� InterFreqNCovHOThdEcN0

� Parameter name: Inter-freq CS target frequency trigger Ec/No THD


� Hystfor2C

� Parameter name: 2C hysteresis

� The default value of this parameter is 6 (3dB)

� TrigTime2C


� The default value of this parameter is D640 (640ms)

�InterFreqNCovHOThdEcN0

�Parameter name: Inter-freq CS target frequency trigger Ec/No THD


�Content: This parameter is used to set measurement control on the event 2C. The event 2C is triggered when the signal quality of the target frequency is above this threshold .


�Set this parameter through SET INTERFREQHONCOV, query it through LST INTERFREQHONCOV.

�Hystfor2C

�Parameter name: 2C hysteresis

�Value range: 0 to 14.5dB, step: 0.5 ;

�Content: The event 2C is applied to non-coverage-based inter-frequency hard handover scenarios where inter-frequency measurement needs to be started. The event 2C is reported when the estimated quality of a non-used frequency is above a certain threshold. For details about the event 2C, refer to the 3GPP TS 25.331. The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2C might not be triggered in time .



�TrigTime2C

�Parameter name: 2C event trigger delay time

�Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms;

�Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2C to measurement signal change.

�The recommended value of this parameter is D640 (640ms)


Course Name


N-72


Contents


3.1 Soft Handover




3.5 Blind Handover

Course Name


N-73


� Characters of Inter-RAT Handover

� Based on handover directions, inter-RAT handover is of two

types:

� UMTS->GSM handover

– UMTS->GSM coverage-based handover

– UMTS->GSM load-based handover

– UMTS->GSM service-based handover

� GSM->UMTS handover

Brief Introduction of Inter-RAT Handover

� Inter-RAT handover refers to the handover between different systems, such as UMTS

and GSM, which use different radio access technologies (RAT).

� Based on handover directions, inter-RAT handover is of two types:

� UMTS->GSM handover (mainly described in this lecture)

� GSM->UMTS handover

� Based on triggering causes, UMTS->GSM handover includes:

� UMTS->GSM coverage-based handover

� The coverage of UMTS is discontinuous at the very beginning. On the border, if the signal quality of UMTS rather than GSM is poor and if all services of the UE are supported by GSM, UMTS->GSM coverage-based handover is triggered.

� UMTS->GSM load-based handover

� If the load of UMTS rather than GSM is heavy and all services of the UE are supported by GSM, UMTS->GSM load-based handover is triggered.

� UMTS->GSM service-based handover

� Based on layered services, traffic of different classes is handed over to different systems. For example, when an Adaptive Multi Rate (AMR) speech service is requested, this call could be handed over to GSM.

Course Name


N-74


Brief Introduction of Inter-RAT Handover

� Advantages

� For coverage, it can solve the problems from one system to

another system

� For capacity, it can enhance the utilizing efficiency of old

equipments(2G->3G)

� Disadvantages

� The flow is complicated, and it demands higher compatibility for

equipments

� Demands more complicated UE

� UMTS->GSM Handover Triggering Conditions

� UMTS->GSM coverage-based handover

� The CPICH Ec/N0 or CPICH RSCP of the UMTS cell to which the UE connects is lower than the corresponding threshold. In addition, there is a GSM cell whose GSM carrier RSSI is higher than the preset threshold.

� UMTS->GSM load-based handover

� The load of the UMTS cell to which the UE connects is higher than the threshold.

� UMTS->GSM service-based handover

� When a service is established, the Core Network (CN) requests a handover of the service to GSM.

Course Name


N-75


Measurement of Inter-RAT Handover


� CPICH_Ec/N0

� CPICH_RSCP

� BOTH

� Reporting mode

� PERIODICAL_REPORTING

� EVENT_TRIGGER

� Event type

� 2D, 2F

� 3A, 3C

�� Measurement quantityMeasurement quantity

� CPICH_Ec/N0 is valid when the Intervalid when the Inter--RAT measurement chooses RAT measurement chooses

PERIODICAL_REPORTING Mode or PERIODICAL_REPORTING Mode or EVENT_TRIGGER Mode.

� CPICH_RSCP is valid when the Intervalid when the Inter--RAT measurement chooses RAT measurement chooses

PERIODICAL_REPORTING Mode or PERIODICAL_REPORTING Mode or EVENT_TRIGGER Mode.

�� BOTH is valid when the InterBOTH is valid when the Inter--RAT measurement chooses RAT measurement chooses

PERIODICAL_REPORTING Mode.PERIODICAL_REPORTING Mode.

Course Name


N-76


Inter-RAT Handover Measurement Events

When the signal quality of any other system is higher than the preset threshold,

the RNC triggers UMTS->GSM handover based on load or service.

3C

When the signal quality of the currently used UMTS frequency is lower than the

preset threshold while the signal quality of any other system is higher than the

preset threshold, the RNC triggers UMTS->GSM handover based on coverage.

3A

When the signal quality of the currently used frequency is higher than the preset

threshold, the RNC disables the compressed mode and stops inter-RAT

measurement.

2F

When the signal quality of the currently used frequency is lower than the preset

threshold, the RNC enables the compressed mode and starts inter-RAT

measurement.

2D

DescriptionDescriptionEventEvent

� 2D Event: initiate GSM measurement

� 2F Event: stop GSM measurement

� 3A Event: based on coverage

� 3C Event: based on non-coverage

Course Name


N-77



2/H-T Q 2dUsed2dUsed ≤

� Event 2D is triggered on the basis of the following formula:

� QUsed is the measurement value of the cell at the currently used frequency.

� TUsed2d is the absolute quality threshold of the cell at the currently used frequency.

Based on CS or PS services, CPICH Ec/No, or RSCP measurement quantity, it can

be Inter-RAT CS measure start Ec/No THD, Inter-RAT PS measure start Ec/No THD,

Inter-RAT CS measure start RSCP THD, or Inter-RAT PS measure start RSCP THD.

� H2d is 2D hysteresis, the hysteresis value of event 2D.

� When the conditions for event 2D are met and maintained in time-to-trigger specified

in 2D event trigger delay time, the UE sends the measurement report of Event 2D.

Course Name


N-78


Key Parameters of 2D Event

� INTERRATCSTHD2DECNO

� Parameter name: Inter-RAT CS measure start Ec/No THD

� The default value of this parameter is -14 ( -14 dB )

� INTERRATPSTHD2DECNO

� Parameter name: Inter-RAT PS measure start Ec/No THD


� INTERRATCSTHD2DECNO

� Parameter name: Inter-RAT CS measure start Ec/No THD [dB]

� Value range: -24~0

� Physical unit: dB

� Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-

RAT measurement, the RNC sends the signaling to activate compressed mode and start inter-

RAT measurement, if the UE reports the event 2D when the measured value is smaller than the

value of this parameter.

� The recommended value of this parameter is -14 ( -14 dB ).

� Set this parameter through SET INTERRATHOCOV, query it through LST INTERRATHOCOV.

� INTERRATPSTHD2DECNO

� Parameter name: Inter-RAT PS measure start Ec/No THD [dB]



� Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-






Course Name


N-79



� INTERRATCSTHD2DRSCP

� Parameter name: Inter-RAT CS measure start RSCP THD

� The default value of this parameter is -100 ( -100 dBm )

� INTERRATPSTHD2DRSCP

� Parameter name: Inter-RAT PS measure start RSCP THD

� The default value of this parameter is -110 (-110 dBm )

� INTERRATCSTHD2DRSCP

� Parameter name: Inter-RAT CS measure start RSCP THD [dB]

� Value range: -115~-25

� Physical unit: dBm

� Content: For CS domain services, when RSCP is used as the measurement quantity for inter-






� INTERRATPSTHD2DRSCP

� Parameter name: Inter-RAT PS measure start RSCP THD [dB]



� Content: For PS domain services, when RSCP is used as the measurement quantity for inter-






Course Name


N-80



� HYSTFOR2D

� Parameter name: 2D hysteresis

� The default value of this parameter is 4 ( 2 dB )

� TRIGTIME2D


� The default value of this parameter is D320 (320 ms )

� HYSTFOR2D

� Parameter name: 2D hysteresis[0.5dB]

� Value range: 0~29

� Physical value range: 0~14.5, step: 0.5


� Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2D might not be triggered in time.

� The recommended value of this parameter is 4 ( 2 dB ).


� TRIGTIME2D

� Parameter name: 2D event trigger delay time[ms]

� Value range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000

� Physical value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000

� Physical unit: ms

� Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2D to measurement signal change.

� The recommended value of this parameter is D320 ( 320ms ).


Course Name


N-81



2/HT Q 2fUsed2fUsed +≥

� Event 2F is triggered on the basis of the following formula:


� TUsed2f is the absolute quality threshold of the cell at the currently used frequency.


be Inter-RAT CS measure start Ec/No THD, Inter-RAT PS measure start Ec/No THD,

Inter-RAT CS measure start RSCP THD, or Inter-RAT PS measure start RSCP THD.

� H2f is 2F hysteresis, the hysteresis value of event 2F.

� When the conditions for event 2F are met and maintained in time-to-trigger specified

in 2F event trigger delay time, the UE sends the measurement report of Event 2F.

Course Name


N-82


Key Parameters of 2F Event

� INTERRATCSTHD2FECNO

� Parameter name: Inter-RAT CS measure stop Ec/No THD


� INTERRATPSTHD2FECNO

� Parameter name: Inter-RAT PS measure stop Ec/No THD


� INTERRATCSTHD2FECNO

� Parameter name: Inter-RAT CS measure stop Ec/No THD [dB]



� Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-RAT measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.



� INTERRATPSTHD2FECNO

� Parameter name: Inter-RAT PS measure stop Ec/No THD [dB]



� Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-RAT measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.



Course Name


N-83



� INTERRATCSTHD2FRSCP

� Parameter name: Inter-RAT CS measure stop RSCP THD


� INTERRATPSTHD2FRSCP

� Parameter name: Inter-RAT PS measure stop RSCP THD


� INTERRATCSTHD2FRSCP

� Parameter name: Inter-RAT CS measure stop RSCP THD [dBm]



� Content: For CS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-RAT measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.

� The recommended value of this parameter is -97 ( -97 dBm ).


� INTERRATPSTHD2FRSCP

� Parameter name: Inter-RAT PS measure stop RSCP THD [dBm]



� Content: For PS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-RAT measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.



Course Name


N-84



� HYSTFOR2F

� Parameter name: 2F hysteresis


� TRIGTIME2F


� The default value of this parameter is D1280 (1280 ms )

� HYSTFOR2F

� Parameter name: 2F hysteresis[0.5dB]




� Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2F might not be triggered in time.



� TRIGTIME2F

� Parameter name: 2F event trigger delay time[ms]




� Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2F to measurement signal change.



Course Name


N-85


The Trigger Algorithm of 3A Event

2/HT Q 3aUsed3aUsed +≥

� Event 3A is triggered on the basis of the following formula:

2/HT M 3aOtherRatOtherRatOtherRat +≥+ CIO


� TUsed is the absolute quality threshold of the cell at the currently used frequency.


be Inter-RAT CS Used frequency trigger Ec/No THD, Inter-RAT PS Used frequency

trigger Ec/No THD, Inter-RAT CS Used frequency trigger RSCP THD, or Inter-RAT

PS Used frequency trigger RSCP THD.

� MOtherRat is the measurement value of the cell (in another RAT) in the reporting range.

� CIOOtherRat is cell individual offset, the offset value of the cell (in another RAT) in the

reporting range.

� TOtherRat is the absolute inter-RAT handover threshold. Based on CS or PS services, it

can be Inter-RAT CS handover decision THD or Inter-RAT PS handover decision

THD.

� H3a is 3A hysteresis, the hysteresis value of event 3A.

� When the conditions for event 3A are met and maintained in time-to-trigger specified

in 3A event trigger delay time, the UE sends the measurement report of event 3A.

Course Name


N-86


Key Parameters of 3A Event

� IRHOUSEDFREQCSTHDECNO

� Parameter name: Inter-RAT CS Used frequency trigger Ec/No

THD


� IRHOUSEDFREQPSTHDECNO

� Parameter name: Inter-RAT PS Used frequency trigger Ec/No

THD


� IRHOUSEDFREQCSTHDECNO

� Parameter name: Inter-RAT CS Used frequency trigger Ec/No THD [dB]



� Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement and the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set measurement control on the event 3A. The event 3A is triggered, when the quality of the currently used UTRAN frequency is below this threshold and the [Inter-RAT CS handover decision THD] is reached.



� IRHOUSEDFREQPSTHDECNO

� Parameter name: Inter-RAT PS Used frequency trigger Ec/No THD [dB]



� Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement and the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set measurement control on the event 3A. The event 3A is triggered, when the quality of the currently used UTRAN frequency is below this threshold and the [Inter-RAT PS handover decision THD] is reached.



Course Name


N-87



� IRHOUSEDFREQCSTHDRSCP

� Parameter name: Inter-RAT CS Used frequency trigger RSCP

THD



� Parameter name: Inter-RAT PS Used frequency trigger RSCP

THD



� Parameter name: Inter-RAT CS Used frequency trigger RSCP THD [dBm]



� Content: For CS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement and the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set measurement control on the event 3A. The event 3A is triggered, when the quality of the currently used UTRAN frequency is below this threshold and the [Inter-RAT CS handover decision THD] is reached.




� Parameter name: Inter-RAT PS Used frequency trigger RSCP THD [dBm]



� Content: For PS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement and the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set measurement control on the event 3A. The event 3A is triggered, when the quality of the currently used UTRAN frequency is below this threshold and the [Inter-RAT PS handover decision THD] is reached.



Course Name


N-88



� INTERRATCOVHOCSTHD

� Parameter name: Inter-RAT CS handover decision THD

� The default value of this parameter is 16 ( -95 dBm )

� INTERRATCOVHOPSTHD

� Parameter name: Inter-RAT PS handover decision THD


� INTERRATCOVHOCSTHD� Parameter name: Inter-RAT CS handover decision THD [dBm] � Value range: 0~63 � Physical value range: -110~-48 (The value 1 corresponds to the physical value -110, 2 to -

109, ..., 63 to -48.)� Physical unit: dBm� Content: For CS domain services,

- If the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 3A. The event 3A is triggered, when the quality of the cell with the target frequency is higher than this threshold and the threshold of the used frequency quality of the corresponding measurement quantity is reached.- If the value of [Inter-RAT report mode] is PERIODICAL_REPORTING, this parameter is usedto evaluate coverage-based inter-RAT handovers at the RNC.Note that the value 0 means the physical value is smaller than -110 dBm.

� The recommended value of this parameter is 16 ( -95 dBm ).� Set this parameter through SET INTERRATHOCOV, query it through LST INTERRATHOCOV.

� INTERRATCOVHOPSTHD� Parameter name: Inter-RAT PS handover decision THD [dBm] � Value range: 0~63 � Physical value range: -110~-48 (The value 1 corresponds to the physical value -110, 2 to -

109, ..., 63 to -48.)� Physical unit: dBm� Content: For PS domain services,

- If the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 3A. The event 3A is triggered, when the quality of the cell with the target frequency is higher than this threshold and the threshold of the used frequency quality of the corresponding measurement quantity is reached.- If the value of [Inter-RAT report mode] is PERIODICAL_REPORTING, this parameter is usedto evaluate coverage-based inter-RAT handovers at the RNC.Note that the value 0 means the physical value is smaller than -110 dBm.

� The recommended value of this parameter is 16 (-95 dBm ).� Set this parameter through SET INTERRATHOCOV, query it through LST INTERRATHOCOV.

Course Name


N-89



� HYSTFOR3A

� Parameter name: 3A hysteresis


� TRIGTIME3A

� Parameter name: 3A event trigger delay time

� The default value of this parameter is D0 ( 0 ms )

� HYSTFOR3A

� Parameter name: 3A hysteresis[0.5dB]




� Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 3A might not be triggered in time.



� TRIGTIME3A

� Parameter name: 3A event trigger delay time[ms]




� Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 3A to measurement signal change.



Course Name


N-90




� Parameter name: Cell individual offset



� Parameter name: Cell individual offset [dB]



� Content: This parameter is used in inter-RAT handover decision. The larger the parameter, the higher the handover priority of the GSM cell. The smaller the parameter, the lower the handover priority of the GSM cell.


� Set this parameter through ADD GSMNCELL, query it through LST GSMNCELL.

Course Name


N-91



2/HT M 3cOtherRatOtherRatOtherRat +≥+ CIO

� Event 3C is triggered on the basis of the following formula:

� MOtherRat is the measurement value of the cell (in another RAT) in the reporting range.

� CIOOtherRat is cell individual offset, the offset value of the cell (in another RAT) in the

reporting range.

� TOtherRat is the absolute inter-RAT handover threshold. Based on CS or PS services, it

can be Inter-RAT CS handover decision THD or Inter-RAT PS handover decision

THD.

� H3c is 3C hysteresis, the hysteresis value of event 3C.

� When the conditions for event 3C are met and the delay requirement specified by the

3C event trigger delay time parameter can be satisfied, the UE sends the

measurement report of event 3C.

Course Name


N-92


Key Parameters of 3C Event

� INTERRATNCOVHOCSTHD

� Parameter name: Inter-RAT CS handover decision THD


� INTERRATNCOVHOPSTHD

� Parameter name: Inter-RAT PS handover decision THD


� INTERRATNCOVHOCSTHD

� Parameter name: Inter-RAT CS handover decision THD [dBm]

� Value range: 0 to 63

� Physical value range: -110 to -48 (The value 1 corresponds to the physical value -110, 2 to -109, ..., 63 to -48)


� Content: This parameter is used to set measurement control on the event 3C. The event 3C is triggered when the quality of the target frequency is higher than this threshold. Note that the value 0 means the physical value is smaller than -110 dBm.

� The recommended value of this parameter is 21 ( -90 dBm ).

� Set this parameter through SET INTERRATHONCOV, query it through LST INTERRATHONCOV.

� INTERRATNCOVHOPSTHD

� Parameter name: Inter-RAT PS handover decision THD [dBm]


� Physical value range: -110 to -48 (The value 1 corresponds to the physical value -110, 2 to -109, ..., 63 to -48)


� Content: The event 3C is triggered when the quality of the target frequency is higher than this threshold. Note that the value 0 means the physical value is smaller than -110 dBm.

� The recommended value of this parameter is 21 ( -90 dBm ).


Course Name


N-93



� HYSTFOR3C

� Parameter name: 3C hysteresis


� TRIGTIME3C


� The default value of this parameter is D640 ( 650 ms )

� HYSTFOR3C

� Parameter name: 3C hysteresis[0.5dB]




� Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer decision mistakes. In this case, however, the event 3C might not be triggered in time.



� TRIGTIME3C

� Parameter name: 3C event trigger delay time[ms]




� Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 3C to measurement signal change.



Course Name


N-94



� PENALTYTIMEFORINTERRATHO

� Parameter name: Inter-RAT handover failure penalty timer

length

� The default value of this parameter is 30 ( 30 s )

� INTERRATHOATTEMPTS

� Parameter name: Inter-RAT handover max attempt times

� The default value of this parameter is 16

� PENALTYTIMEFORINTERRATHO

� Parameter name: Inter-RAT handover failure penalty timer length [s]


� Physical unit: s

� Content: An inter-RAT handover to a GSM cell may fail due to the heavy load of the GSM cell. Therefore, in the period of time specified by this parameter, inter-RAT handover requests are not sent to the GSM cell.

� The recommended value of this parameter is 30 ( 30 s ).


� INTERRATHOATTEMPTS

� Parameter name: Inter-RAT handover max attempt times


� Physical unit: times

� Content: This parameter specifies the maximum number of attempts for the RNC to perform inter-RAT handovers after a non-coverage-based inter-RAT handover failure. For later handover attempts, target cells must be selected. Ensure that the target cells have not been tried but satisfy the handover conditions. No matter the inter-RAT handover failure penalty timer expires or not.

� The recommended value of this parameter is 16.


Course Name


N-95



� INTERRATMEASTIME

� Parameter name: Inter-RAT measure timer length [s]

� The default value of this parameter is 60 ( 60 s )

� INTERRATMEASTIME

� Parameter name: Inter-RAT measure timer length [s]


� Physical unit: s

� Content: After inter-RAT measurement starts, if no inter-RAT handover is performed when this timer expires, the inter-RAT measurement is stopped. In addition, the compressed mode is deactivated, if any. The value 0 indicates the timer is not to be enabled.

� The recommended value of this parameter is 60 ( 60 S ).


Course Name


N-96


Contents


3.1 Soft Handover




3.5 Blind Handover

Course Name


N-97


Blind Handover Measurement

� Blind handover means UE can directly handover to the

neighboring cell without measuring it.

� If the serving frequency signal is getting worse quickly, but UE can not trigger a inter-

frequency measurement and hard handover in time, blind handover might be used to

save the call.

� In Huawei implementation, blind handover can be triggered by intra-frequency

measurement event 1F.

Course Name


N-98



� Where:

� MOld is the measurement value of the cell signal that becomes

worse

� T1f is the absolute threshold of event 1F.

� H1f is the hysteresis value of event 1F.

2/HTLogM10 f1f1Old −≤⋅

� For different intra-frequency measurement quantity, the threshold T1f are set to 1F

Event Absolute EcNo Threshold, 1F Event Absolute RSCP Threshold respectively.

Course Name


N-99



Absolute Threshold T1f

Reporting event 1F

Measurement Quantity

Time

Cell 1

Hysteresis H1f /2

1F Trigger Delay Time

� If the signal quality of a cell in the active set is worse than T1f - H1f /2 , and last for a

certain time 1F Event Trigger Delay Time, then UE reports event 1F.

Course Name


N-100


Key Parameters of Event 1F

� INTRAABLTHDFOR1FECNO

� Parameter name: 1F event absolute EcNo threshold

� The recommended value is -24 dB

� INTRAABLTHDFOR1FRSCP

� Parameter name: 1F event absolute RSCP threshold

� The recommended value is -115 dBm

� INTRAABLTHDFOR1FECNO

� Parameter name: 1F event absolute EcNo threshold

� Value range: -24 to 0

� Physical value range: -24 to 0 dB. Step: 1

� Content: The absolute EcNo threshold of the event 1F.It is easier to trigger event 1F if the value increases. It is harder to trigger event 1F if the value decreases.

� Recommended value: -24

� INTRAABLTHDFOR1FRSCP

� Parameter name: 1F event absolute RSCP threshold

� Value range: -115 to 25

� Physical value range: -115 to 25 dB. Step: 1

� Content: The absolute RSCP threshold of the event 1F.It is easier to trigger event 1F if the value increases. It is harder to trigger event 1F if the value decreases.

� The recommended value is -115 dBm

� For RNC level, set these two parameter through SET INTRAFREQHO, query them through LST INTRAFREQHO, and modify them through SET INTRAFREQHO

For cell level, set these two parameter through ADD CELLINTRAFREQHO, query them through LST CELLINTRAFREQHO, and modify them through MOD CELLINTRAFREQHO.

Course Name


N-101


Key Parameters of Event 1F

� HYSTFOR1F


� The recommended value is 8, namely 4 dB

� TRIGTIME1F


� The recommended value is D640, namely 640 ms

� HYSTFOR1F



� Physical value range: 0 to 7.5 dB. Step: 0.5

� Content: The hysteresis value of the event 1F. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.

� Recommended value: 8

� TRIGTIME1F



� Physical value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

� Content: The trigger delay time of the event 1F. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.

� Recommended value: D640

� For RNC level, set these two parameter through SET INTRAFREQHO, query them through LST INTRAFREQHO, and modify them through SET INTRAFREQHO

� For cell level, set these two parameter through ADD CELLINTRAFREQHO, query them through LST CELLINTRAFREQHO, and modify them through MOD CELLINTRAFREQHO.

Course Name


N-102


Blind Handover Decision

� After receiving event 1F of best cell from UE, the RNC

would check if blind handover neighbor is configured for the

cell.

� If multiple blind handover neighbors are configured, the

RNC would perform blind handover to the target cell with

the highest priority

� When we configure the inter-frequency neighbor cell or GSM neighbor cell, two

parameters of blind handover is included: Blind Handover Flag and Blind Handover

Priority.

Course Name


N-103


Key Parameters of Blind Handover

� BLINDHOFLAG

� Parameter name: Blind handover flag

� The default value is FALSE

� BLINDHOPRIO

� Parameter name: Blind handover Priority

� The value is set according to actual situation.

� BLINDHOFLAG

� Parameter name: Blind handover flag

� Value range: FALSE, TRUE

� Content: This parameter indicates whether the neighboring cell is the target cell for blind handovers. If the value is TRUE, blind handovers can be performed to the neighboring cell.

� Default value: FALSE

� BLINDHOPRIO

� Parameter name: Blind handover Priority


� Content: The value 0 indicates the highest priority, and 30 the lowest. A neighboring cell of a cell must have a unique priority.

It is suggested 0 to 15 assigned to the neighboring cells superposed to the cell specified by [CELLID]. The success rate of handovers to these cells can be guaranteed.

Neighboring cells with priorities from 16 to 30 can be performed with blind handovers, but the handovers may fail.

� Recommended value (default value): none

� Set these two parameter through ADD INTERFREQNCELL or ADD GSMNCELL, query them through LST INTERFREQNCELL or LST GSMNCELL, and modify them through MOD INTERFREQNCELL or MOD GSMNCELL.

Course Name


N-104

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Documents

05 Huawei WCDMA Handover Principle and Relevant Parameters