LTE Interoperability in Connection Mode (LTE-GU)

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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.

LTE Interoperability in Connection Mode (LTE->G/U)

Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved. Page3

Contents

1. LTE Interoperability in Connection Mode

2. CS Interoperability


Contents1. LTE Interoperability in Connection Mode

1.1 Technical Overview and Basic Concepts

1.2 Measurement Configuration

1.3 Measurement Triggering/Stopping Phase of an IRAT Handover

1.4 Redirection

1.5 Blind Handover

1.6 Measurement Phase of an IRAT Handover

1.7 Decision Phase of an IRAT Handover

1.8 Execution Phase of an IRAT Handover

1.9 IRAT Signaling Procedure in Connection Mode


States of UE at Switch on

Page5

Idle Mode

Connection Mode

Data Service Continuity

PS HO

CCO/NACC

Redirection

Voice Service Continuity

CS FallBack

SRVCC

States of UE at Switch on

*

*Related to interoperability which will be discussed in this course


Coverage-based

Connection Mode

Discussing

Frequency-priority-based

Intra-frequency HO

Mobility Management Overview in Connection Mode

Page6

Inter-frequency HO

Inter-RAT HO

Load-based

UL-quality-based

Service-based

Distance-based

SPID-based HO back to the HPLMN

CSFB

PS HO

SRVCC

CCO/eNACC

Redirection

Types Causes/Scenario Execution

Discussed

Not be discussed

UE States


Handover Procedure

Page8


Neighbor Relationship Management Overview Neighbor relationships define the relationships between

the serving cell and its neighboring cells, and they play a

fundamental role in handovers.

Neighbor relationships are planned in the network design

stage. They are automatically adjusted by ANR which is

enabled.

There are three types of neighboring cells

Page9

Types The Max Number of NcellThe Max Number of

Nfrequency

Intra-frequency Ncell 64 NA

Inter-frequency Ncell 64 8

Inter-RAT Ncell128(UTRAN) 16(UTRAN)

64(GERAN) 16(GERAN)


Priority of the Neighboring Cell

For normal handover, if the target system is E-UTRAN or UTRAN, the

eNodeB preferentially selects the cells with parameters

EUTRANINTRAFREQNCELL.CellMeasPriority, EUTRANINTERFREQNCELL.

CellMeasPriority, or UTRANNCELL.CellMeasPriority setted as

HIGH_PRIORITY.

For the blind handover, The candidate cells must be the neighboring cells

with blind-handover priorities ≠ 0.

Page10


indicates whether the UE is capable of frequency-specific or RAT-specific measurements and handovers.

UE Capability

Page11

UE

UE Capability InformationIncludes the “UECapabilityInformation” parameter-UE-CapabilityRAT-ContainerList--UE-EUTRA-Capability---featureGroupIndicators--UE-EUTRA-Capability-v9a0---featureGroupIndRel9Add-r9--UE-EUTRA-Capability-v1020---featureGroupIndRel10-r10

eNBUE Capability Enquiry

The MME may inform the eNodeB of UE capabilities.

If the MME does not inform the eNodeB of UE capabilities, the eNodeB

initiates UE capability transfer over the radio interface to a UE, and the

UE informs the eNodeB of the UE capabilities through the UE Capability

Information IE.






1.4 Redirection

1.5 Blind Handover






After a UE establishes a radio bearer, the eNodeB delivers the

Measurement Configuration to the UE in an RRC Connection

Reconfiguration message.

The measurement configuration consists of

Measurement Objects

Reporting Configurations

Other Parameters

HO Measurement Configuration Overview

Page13

RRC Connection Reconfiguration Request

eNBUE

RRC Connection Reconfiguration Complete

RRC Connection Reconfiguration RequestMeasurement Configuration - measObjectToRemoveList- measObjectToAddModList- reportConfigToRemoveList- reportConfigToAddModList- measIdToRemoveList- measIdToAddModList- quantityConfig- measGapConfig- s-Measure


Measurement Configuration After UE attachment, eNodeB sends RRC

reconfiguration message which includes intra/intre-

frequency/IRAT measurement control info which

inform UE to perform intra/intre-frequency/IRAT

measurement It contains all intra/intre-frequency/IRAT measurement and report configuration, including A1(optional), A2(optional) and A3(mandatory) event.

Trace from eNodeB

Page14


The Measurement Configuration for Inter-RAT HO For inter- RAT HO, the measurement configuration includes:

Inter-RAT measurement object: UTRAN or GERAN

Reporting configuration

Inter-RAT handover thresholds

Hysteresis

Time-to-trigger

Triggering quantity for handovers to UTRAN

Maximum number of cells to be reported

Interval between reports

The number of periodic measurement reports

Measurement quantity configuration

Measurement gap configuration

Page15


Inter-RAT Measurement Object Overview

Page16


eNBUE


RRC Connection Reconfiguration RequestMeasurement Configuration - measObjectToAddModList-- measObjectId-- measObject measObjectEUTRA --- carrierFreq --- allowedMeasBandwidth--- presenceAntennaPort1--- neighCellConfig--- offsetFreq --- cellsToAddModList---- cellIndex ---- physCellId---- cellIndividualOffset

Measurement objects are the objects that UEs measure.

Measurement object information includes the target system,

target frequency and target cell for a UE to measure, as well

as the measurement bandwidth and frequency-specific

offset if target system is EUTRAN.


Inter-RAT Measurement Object Parameters

Parameters Description

carrierFreqIndicates the DL EARFCN of the inter-frequency E-UTRAN cell

allowedMeasBandWidth

Indicates the measurement bandwidth for inter/intra-frequency neighboring cells

PresenceAntennaPort1

Indicates whether all of the inter-frequency neighboring cells are configured with the double-TX antenna.

neighCellConfig

Indicate whether all the neighbor have the same configuration or not

offsetFreqIndicates the frequency offset of the inter-frequency neighboring cell

Page18


Data Configuration of Inter-RAT Measurement Object UMTS

GERAN

Page19


UTRAN Measurement Object

Page20


eNBUE


RRC Connection Reconfiguration RequestMeasurement Configuration - measObjectToAddModList-- measObjectId-- measObject measObjectUTRA --- carrierFreq --- offsetFreq--- cellsToRemoveList--- cellsToAddModList---- cellIndex---- physCellId--- cellForWhichToReportCGI


GERAN Measurement Object

Page21


eNBUE


RRC Connection Reconfiguration RequestMeasurement Configuration - measObjectToAddModList-- measObjectId-- measObject measObjectGERAN --- carrierFreqs--- offsetFreq--- ncc-Permitted--- cellForWhichToReportCGI


Tracing Case – Measurement Object

Page22


Report Configuration

Reporting configurations consist of the parameters

related to specific events.

Page23


eNBUE


RRC Connection Reconfiguration RequestMeasurement Configuration - reportConfigToAddModList-- reportConfigId-- reportConfig reportConfigEUTRA--- triggerType event---- eventId e.g. eventA1----- a1-Threshold threshold-RSRP---- hysteresis---- timeToTrigger--- triggerQuantity (RSRP)--- reportQuantity--- maxReportCells--- reportInterval--- reportAmount


Events for Report Configuration

Page24

Events

Threshold Action

inter-frequen

cy or IRAT

A1Signal quality in the serving cell is higher than a specified threshold

The eNodeB stops inter-frequency or inter-RAT measurements.

A2Signal quality in the serving cell is lower than a specified threshold

The eNodeB starts inter-frequency or inter-RAT measurements

intra-frequency/inter-frequen

cy

A3

Signal quality in at least one intra-frequency/inter-frequency neighboring cell is higher than that in the serving cell

Source eNodeB sends an intra-frequency/inter-frequency handover request.

inter-frequen

cy

A4

Signal quality is higher than a specified threshold in at least one inter-frequency neighboring cell

Source eNodeB sends an inter-frequency handover request.

A5 A2 + A4 Source eNodeB sends an inter-frequency handover request.

IRAT

B1

Signal quality is higher than a specified threshold in at least one inter-RAT neighboring cell

source eNodeB sends an inter-RAT handover request.

B2 A2 + B1source eNodeB sends an inter-RAT handover request.


Tracing Case – Event 3 Report Configuration

Page26


Other Parameters Related to Events

Page27

Example:

Hysteresis

To reduce the number of event reports generated because of radio signal

fluctuation, the hysteresis to the signal quality is used in the entering and

leaving conditions for each event.

Time-to-Trigger

When the entering condition of an

event is met, the UE does not report

the cell measurement result

associated with the event to the

eNodeB until the entering condition is

met throughout a specified period, as

defined by the time-to-trigger

parameter.

Triggering Quantity and

Reporting Quantity

RSRP & RSRQ


1.Hysteresis 2.Time-to-trigger

Data Configuration of Reporting Configuration(1/2)

Page28

UMTS

GERAN


Data Configuration of Reporting Configuration(2/2)

3. Triggering quantity for handovers to UTRAN

4. Maximum number of cells to be reported

5. Interval between reports

6. The number of periodic measurement reports

Page29

33

44

55

66


A: Measurement value at the physical layer

B: Measurement value obtained after L1 filtering.

C :Measurement value obtained after L3 filtering.

Other Parameters—Measurement Filtering

Page30

EUTRAN

UTRAN

GERAN

EUTRAN


Tracing Case – Filtering Configuration

This filtering is performed by RRC, smoothing

measurement to resist fast fading effect. A larger value

of this parameter indicates a stronger smoothing effect

and higher resistance to fast fading, but it may weaken

the tracing capability towards varying signals

Page32


Tracing Case - Measurement ID

Based on the object and report configuration, eNodeB

creates one or more measurement ID linked with object ID

and report ID. And this ID should be also included in the UE

report, so eNodeB can differentiate each reports

Page33





1.3 Measurement Triggering/Stopping Phase of an IRAT

Handover

1.4 Redirection

1.5 Blind Handover






IRAT HO Scenario

Page35

Inter-RAT HOService-based HO

Coverage-based HO

Load-based HO

UL-quality-based HO

Distance-based HO

SPID-based HO back to the HPLMN

CSFB(it will be introduced in Chapter4)


Coverage-based Handover OverviewMoves to neighbor LTE FDD cell

Moves to neighbor LTE TDD cell

Intra-FrequencyInter-Frequency

Using different event threshold to decide handover target Handover Priority: Intra-frequency > inter-frequency , Intra-RAT > inter-

RAT Handover between TDD/FDD looks as Inter-Frequency of LTE system

Inter-RAT

LTE FDD LTE TDD

UMTS

Threshold of

trigger Inter-freq

HO (IF A2) is

higher than

threshold of

trigger Inter-RAT

HO (IR A2), which

means that inter-

freq HO is

triggered earlier

than inter-RAT

HO.

Moves out of LTE coverage

If UE under UMTS move to LTE coverage, there are two options: Service is still provided by UMTS. When service

ends, UE will camp on LTE network by cell reselection

UMTS triggers Inter-RAT handover to LTE

Moves to LTE

coverage

Page36


Event Related with Coverage-based HO The eNodeB delivers the measurement configuration

related to event A2 to a UE in connected mode to monitor

the signal quality of the serving cell. The eNodeB may

deliver measurement configurations for two types of

events A2 to the UE

Page37

...•If the signal quality in the serving cell is lower than the

specified threshold

...

•If the signal quality in the serving cell further deteriorates

and the eNodeB does not perform a handover for the UE, the

UE reports event A2 for blind handover.

Event A2 for IRAT measurement

Event A2 for blind handover


Data Configuration of Coverage-based HO The switches UtranRedirectSwitch and

GeranRedirectSwitch under the ENodeBAlgoSwitch.

HoModeSwitch parameter specify whether coverage-

based handovers to GERAN and UTRAN cells are enabled,

respectively.

Page38


Measurement Trigger Conditions of IRAT HO by Event A2

Entering condition: Ms + Hys < Threshold

Leaving condition: Ms – Hys > Threshold

A2 Event

LTE

GSM/UMTS Coverage

Intra-LTE Inter-RAT

According to radio link condition (LTE: RSRP/RSRQ)

Moves to neighbor LTE

cell

Moves out of LTE

coverage

Page39


Data Configuration Of Measurement Trigger Condition of IRAT HO by Event A2

Hysteresis,

threshold and time

to trigger related

with event A2

Page41

RSRP/RSRQ Measurement quantities


Target-based Setting of Inter-RAT Event A2 For GU, RSRP thresholds can be adjusted via the

offsets.

The offsets do not affect the RSRQ thresholds for

inter-RAT measurement event A2.

Page42

Entering condition: Ms + Hys < Threshold-10

Leaving condition: Ms – Hys > Threshold-10


Measurement Stopping Condition of IRAT HO by Event A1

The event A1 threshold

must be higher than the

event A2 threshold to

ensure that event A1

can stop inter-RAT

measurements in

coverage-based inter-

RAT handovers.

Page44

Entering condition: Ms - Hys > Thresh

Leaving condition: Ms + Hys < Thresh


Data Configuration Of Measurement Stopping Condition of IRAT HO by Event A1

Hysteresis,

threshold and time

to trigger related

with event A1

Page46

These parameters are the same to both A1 and A2


Blind-Handover Triggering by Event A2

In coverage-based IRAT handovers, the eNodeB delivers a measurement

configuration related to event A2 for blind handover if the signal quality of

the serving cell deteriorates to a specified level and the UE has not

been handed over.

Event A2 for blind handover can trigger both inter-frequency and IRAT

blind handovers.

the RSRP threshold and RSRQ threshold of event A2 for blind handover are

the same and specified in the following parameters.

Other parameters related to blind handover events A1 and A2 are

specified by parameters for inter-RAT blind handovers

Page47


Relationship between IRAT HO and Blind HO The eNodeB delivers event A2 for blind handover but not event A2 for inter-

frequency or inter-RAT measurement if both the following conditions are met:

The UE does not support inter-frequency or inter-RAT measurement.

The threshold of event A2 used for inter-frequency or inter-RAT

measurement is lower than the threshold of event A2 for blind handover.

A coverage-based inter-RAT blind handover can be performed in the form of a

blind redirection.

If the target system is GERAN, it can also be performed in the form of a blind

CCO.

If VoIP services are running on the UE that reports event A2 for blind

handovers, the eNodeB determines an IRAT handover policy(discussed later)

based on the handover policy configuration and UE capability.

Page49


When high load occurs in LTE but low load in GSM/UMTS,

make some UEs handover to GSM/UMTS

Page50

load transfer

LTE

High load

GSM Low loadUMTS

Load Evaluation

Load Balancing Decision

Inter-RAT HO based

Measurement

Event B1 Triggered

UE eNB

Measure Report

HO Decision

IR-HO Execute

Measurement GAPEvent B1 Parameters

Blind HO

YBlind HO Switch is ON & target cell is in blind HO List?

target cell

N

Blind HO list can be configured according to operator's strategy and networking scenarios

Multiple handover schemes according to the capability of network, and UE e.g. PSHO, CCO/NACC, Redirection

Load based Handover: Inter-RAT


Data Configuration of Load-based HO

Blind HO

UEs in connected mode are handed over to UTRAN cells

UEs are handed over to GERAN cells

and

and


UL-Quality-based Handover

X

HO

Scenario:

DL quality is good,

but UL quality is

limited, which result

to poor service

experience.

Principle:

When UL IBLER is

higher than

threshold, trigger

handover to a better

neighbor cell.

√

Improve Edge User Experience in Interference or UL-Limited Scenario

Page52

Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved. Page 53

UL Quality threshold are set by the system.

Description•Due to the UL interference, the coverage in UL is limited compared to DL•The UE has limited power•The HO algorithms are implemented for DL HO

Benefit•Guarantee Service Continuity in UL limited LTE networks

2. Sends target cell and instructs UE to initiate GAP/B1 measurement

3. Sends GAP/B1 measurement report to the eNodeB

1. UL Quality > threshold

4. Instruct UE to HO

12

3

4

LTE(F1)

2G/3G or LTE(F2)

UL-Quality-based Inter-RAT Handover


Service-based Handover: Inter-RAT Handover voice service when E-RAB

established to UMTS/GSM

To improve efficiency and capacity of

whole system

To save the investment at the

beginning of LTE

Page54

3G/2G coverage

LTE coverage

Handover to 3G/2G according to service

UE eNB

UE initiate service

Only Voip E-RAB

E-RAB Initial

HOMeasurement

Measurement Configuration

Event B1 trigger

Measure Report

HO Decision

HO Execute

Y


Data Configuration of Service-based HO

Page55


Distance-based HO Overview

Page57


Data Configuration of Distance-based HO

Page59


Background of Inter-PLMN Handover Besides handover between PLMNs which belong

to different operators, there is another scenario

where an operator may own multiple PLMNs

which are respectively used to provide coverage

for different RATs.

To enable UE handovers between PLMNs owned

by the same operator, inter-PLMN handovers are

introduced.

Page60


Data Configuration of Inter-PLMN HO(1/2)

Page61


Data Configuration of Inter-PLMN HO(2/2)

Page62

MAPPING


SPID-based HO Back to the HPLMN Overview(1/2) A handover back to the HPLMN policy defines whether a UE can

be handed over from another PLMN to its HPLMN when it moves

back to an E-UTRAN of its HPLMN.

The SpidCfg.HoBackToHPLMNSwitch parameter specifies

whether handover back to the HPLMN is allowed for UEs with a

specific SPID.

Page63

Operator A

Operator B

Inter-PLMN Handover to A’s home PLMN

Scenario:

Operator A's coverage is embedded in

Operator B's coverage, i.e. a UE does not

lose coverage from operator B when

entering coverage of operator A.

Operator B‘s eNB needs to know the

subscriber’s home PLMN to decide

whether a handover towards A‘s network

shall be triggered.

Operator A’s subscriber allowed to

roam in B’s network


UE

Parameter and Setting

Spid HoBackToHPLMNSwitch

1 1 FALSE(FALSE)

2 2 TRUE(TRUE)

3 3 TRUE(TRUE)

4 4 FALSE(FALSE)

5 5 ...... ... ...... 256 ...

SPID-based HO Back to the HPLMN Overview(2/2) For roaming subscribers, HPLMN cell will be more suitable to be

selected than roaming cell when entering HPLMN coverage area

through connected mode handover.

This kind of handover is also an inter-PLMN handover. Before

using this policy, ensure that the HPLMN has the frequency with

the highest priority in the cell reselection policy, and inter-PLMN

handover.


Conditions of SPID-based HO Back to the HPLMN Handover back to the HPLMN takes effect for a UE

only when all the following conditions are met:

Page65

• Comparing with serving cell, a neighbour cell should has higher frequency priorities and a different PLMN• The parameter

SpidCfg.HoBackToHPLMNSwitch

parameter is set

to TRUE(TRUE)

• ENodeBAlgoSwitch.HoAlgoSwitch.InterPlmnHoSwitch is selected.

Switch related to SpidCfg is enable

High frequency priorities and different PLMN

Switch related to InterPlmnHo is enable

SPID-based HO Back to the HPLMN


Example of SPID-based HO Back to the HPLMN

Page66

PLMN B PLMN A

CN

1. A’s UE access to B’s network

2. eNB/RNC get SPID of this UE from B’s MME

3. eNB check the neighbor cell list by

this PLMN when UE HO to it, if find

matched cell, ask the UE to HO

HO to HPLMN happens in this cell

1

2

3

Handover to HPLMN based SPID can facilitate roaming user back to its network to save the cost.






1.4 Redirection

1.5 Blind Handover






Redirection Definition Redirection is a method of transferring UEs between cells and is a type

of handover when "handover" is used as a generic term.

When a handover cannot be performed in an emergency or due to

equipment limitations, the eNodeB sends the UE an RRC Connection

Release message, which contains information about a neighboring

frequency in the LTE system or in another RAT system. Using this

message, the eNodeB instructs the UE to initiate a random access

procedure towards an inter-frequency or inter-RAT neighboring cell so

that the UE can resume its services.

Compared with handovers, redirections do not include a

procedure for initiating a handover request towards a

neighboring cell. Therefore, redirections have lower requirements for

equipment capabilities and can be rapidly performed. The two

methods differ in the way to transfer UEs.Page68


Redirection Data Configuration The 2G/3G network are generally mature, and may not support IRAT

handovers from the E-UTRAN. In this situation, redirections instead of

inter-RAT handovers can be performed on UEs. Therefore, network

capabilities must be collected to determine whether to enable handovers

or redirections for UE transfer.

If both handovers and redirections are enabled, the eNodeB

preferentially uses handovers to transfer UEs.

Page69






1.4 Redirection

1.5 Blind Handover






Blind Handovers Overview To reduce delay, the eNodeB may select a target cell for handover in

the absence of the measurement information. This type of handover is

called a blind handover, which is a generic term.

Blind handover consists of

The handover without neighboring cell measurements

CCO

Redirection

If eNodeBs decide to perform blind handovers, they will not deliver the

GAP measurement and related measurement control order but directly

deliver handover commands, CCO indicators, or redirection indicators

to the UEs.

Page72


Comparison between Blind HO and Normal HO

Measurement based handover: HO must be trigged by intra/inter-frequency/IRAT measurement report

Blind handover: Skip intra/inter-frequency/IRAT measurement, directly execute HO based on priority configuration

Once blind HO is activated, eNodeB directly decide the HO target based on the priority configuration of each neighbor

Measurement report (A2)

intra/inter-frequency/IRAT measurement activate


Handover command

Measurement based HO


Handover command

Blind Ho

Page73


The eNodeB randomly selects target cells or frequency

The Target Selection Procedure of the Blind HO

Page74

Star The eNodeB selects the system with the highest priority

Are valid Ncells available for the blind-HO?

The eNodeB selects the Ncells with the highest blind-HO priority

The eNodeB selects a frequency based on the frequency priority

The eNodeB filters the target cells or frequencies

Is only one target cell or frequency available ?

The eNodeB performs a blind-HO

No

Yes

Yes

No

Attention: Firstly select a cell in the intra-RAT system and then a inter-RAT system, for the priority of EUTRAN is higher than

that of an inter-RAT system.


Data Configuration of IRAT Priority

1. The eNodeB selects the system with the highest

priority as the target system.

The priorities of EUTRAN systems

Page76


Data Configuration of IRAT Priority

1. The eNodeB selects the system with the highest priority

as the target system.

The priorities of IRAT systems

Page77


Data Configuration of Neighbor Cell Blind HO Priority

2. The eNodeB selects a neighboring cell for the blind

handover.

Within EUTRAN system

Page78

EUTRAN


Data Configuration of Neighbor Cell Blind HO Priority

2. The eNodeB selects a neighboring cell for the blind

handover.

In IRAT system

Page79

UTRAN

GERAN


Data Configuration of the Neighbor Frequency Priority

Page80

…UTRAN

GERAN


Data Configuration of Filtering the Target Frequencies3.The eNodeB filters the blind-handover targets to prevent a blind

handover to an inappropriate target.

For cell: The filtering of the target neighboring cells is the

same as that in Handover Decision.

For frequency: When filtering the target frequencies, the

eNodeB filters out the frequencies whose PLMN is different

from the PLMN of the serving cell.

Page81


Data Configuration of Filtering the Target Frequencies

Page82

UTRAN

GERAN






1.4 Redirection

1.5 Blind Handover






IRAT HO Measurement Overview Step1: When inter-RAT measurements are required, the

eNodeB delivers to the UE a Measurement Configuration

message containing the inter-RAT measurement

configuration, instructing the UE to perform inter-RAT

measurements.

Step2: If the triggering condition of inter-RAT handover event

B1 or B2 are met, event B1 or B2 will be reported. Basing on

the reported inter-RAT measurement result, the eNodeB

makes an inter-RAT handover decision.

The measurement phase of the inter-RAT handover consists of

inter-RAT measurement configuration, setup of measurement

gaps, and triggering of event B1 or B2.

Page84


Event B1/B2 Triggering Scenario Coverage-based inter-RAT handovers

can be triggered by event B1 or B2

The type of event used to trigger coverage-based inter-RAT

handovers is specified by the InterRatHoComm.

InterRatHoEventType parameter.

Other types of inter-RAT handover

can be triggered only by event B1. If event B2 is used to

trigger non-coverage-based inter-RAT handovers, cell center

users (CCUs) do not report event B2.

Page85


IRAT Report Configuration - Event B1

Page86


eNBUE


RRC Connection Reconfiguration RequestMeasurement Configuration - reportConfigToAddModList-- reportConfigId-- reportConfig ReportConfigInterRAT--- triggerType event---- eventB1----- b1-ThresholdUTRA or----- b1-ThresholdGERAN---- hysteresis---- timeToTrigger --- maxReportCells --- reportInterval --- reportAmount

Event B1 indicates that the signal quality is higher than a

specified threshold in at least one inter-RAT neighboring cell.

When the information about the cells that meet the triggering

condition is reported, the source eNodeB sends an inter-RAT

handover request.


Event B1 Triggering Mechanism

Page87

EUTRAN Cell

UTRAN Cell

Entering condition: Mn + Ofn - Hys > Thresh

Leaving condition: Mn + Ofn + Hys < Thresh


Data Configuration Related to Event B1

Page88

Ofn

Hys

Thresh

time-to-trigger

Hys

time-to-trigger

Thresh

URAN

GERAN

Thresh


IRAT Report Configuration - Event B2

Page89


eNBUE


RRC Connection Reconfiguration RequestMeasurement Configuration - reportConfigToAddModList-- reportConfigId-- reportConfig ReportConfigInterRAT---triggerType event---- eventB2----- b2-Threshold1----- b2-Threshold2------ b2-Threshold2UTRA or------ b2-Threshold2GERAN---- hysteresis---- timeToTrigger --- maxReportCells --- reportInterval --- reportAmount

Event B2 indicates that the signal quality in the serving cell is

lower than a threshold and that the signal quality in at least one

inter-RAT neighboring cell is higher than another threshold.

When the information about the cells that meet the triggering

condition is reported, the source eNodeB sends an inter-RAT

handover request.


Event B2 Triggering Mechanism

Page90

TTT

B2-1

Threshold 2

Threshold 1

EUTRA Cell

UTRACell Hys

Ofn-Hys

Mn

Mp

B2-2 B2 Triggered

•Entering condition: Ms + Hys < Thresh 1 and Mn + Ofn - Hys > Thresh 2 •Leaving condition: Ms - Hys > Thresh 1 or Mn + Ofn + Hys < Thresh 2


Data Configuration Related to Event B1

Event B2 uses the same set of parameters as event B1

except four parameters: the triggering quantity related to

Thresh 1, the measurement quantity related to Thresh 2,

Thresh 1, and Thresh 2. For details about the four

parameters, see the following Tables.

Thresh 1 for event B2

Thresh 2 for event B2

Page91

Triggering Quantity Thresh 1

The same as the triggering quantity of event A2

RSRPInterRatHoCommGroup.InterRatHoA2ThdRSRP

RSRQInterRatHoCommGroup.InterRatHoA2ThdRSRQ

Measurement Quantity Thresh 2

UTRANRSCP

InterRatHoUtranGroup.InterRATHoUtranB1ThdRSCP

Ec/NoInterRatHoUtranGroup.InterRATHoUtranB1ThdEcN0

GERAN RSSI InterRatHoGeranGroup.InterRATHoGeranB1Thd


Measurement gaps are applicable to inter-frequency and

inter-RAT measurements.

Measurement GAP

Page92

During the measurement

gaps the UE:

not transmit any data

is not expected to tune

its receiver on the E-

UTRAN serving carrier

frequency.


Data Configuration of IRAT Measurement Priorities

This is only available to IRAT measurements on the

UTRAN.

Page94


Event-Triggered Periodical Reporting

After an event is reported at the first time, the

measurement results associated with the event are

reported periodically by UE, which is called event-

triggered periodical reporting.

Page95

eNB

UE

eNB

Periodical Reporting

Report Interval (ms120, ms240, ms480, ms640, ms1024, ms2048, ms5120, ms10240,

min1, min6, min12, min30, min60)


The Purpose of IRAT Periodical Reporting

There are three purposes defined for periodical reporting:

Report Strongest Cells.

Report Strongest Cells For SON.

Report CGI.

Page96


eNBUE


RRC Connection Reconfiguration RequestMeasurement Configuration - reportConfigToAddModList-- reportConfigId-- reportConfig ReportConfigInterRAT---triggerType periodical ---- purpose--- maxReportCells --- reportInterval --- reportAmount






1.4 Redirection

1.5 Blind Handover






Handover Decision Overview

Measurement ReportCheck measurement result

Decide target cell

Page98

In this phase, the eNodeB checks the measurement result reported by

the UE and decides whether to perform an inter-RAT handover for a

UE or the blind-handover priorities and judges to triger a handover.

The eNodeB derives a list of candidate cells from the measurement

report sent by the UE.

For normal handover, the list is based on the signaling strength, while

for a blind handover, it is based on the blind-handover priorities.

If the eNodeB receives measurement reports about different RATs, it

processes the reports in a First In First Out (FIFO) manner.


Filtering Principle of Target Cell The eNodeB filters out the following cells from the

neighboring cell list:

Page99

cell1

cell2

cell3

cell4

cell5

cell6

cell3

cell5

Blacklisted neighboring cells

Neighboring cells that have a different PLMN

from the serving cell if the inter-PLMN handover

switch is disabled. Refer to the section Inter-

PLMN Handovers

Neighboring cells with a handover prohibition

flag.

Neighboring cells in the areas indicated by the

IE Handover Restriction List in the INITIAL

CONTEXT SETUP REQUEST message sent from

the MME.






1.4 Redirection

1.5 Blind Handover






Handover Execution Overview In this phase, the UE and the eNodeB exchange signaling over

the radio interface according to the protocol.

The LTE system uses hard handovers, that is, only one radio link

is connected to a UE at a time.

The source and target eNodeBs exchange signaling and data

through X2/S1 adaptation.

Page101

In the case of IRAT HO, the eNodeB sends a handover request and forwards data over the S1 interface.


Data Forwarding Overview

Definition: After the source eNodeB sends a handover

command to the UE, the UE detaches the connection from

the source eNodeB. The source eNodeB then forwards the

uplink (UL) data that is received out of order and the DL

data to be transmitted, to the target eNodeB.

Data forwarding prevents a decrease in the data transfer

ratio and an increase in the data transfer delay that are

caused by user data loss during the handover.

Page103


Data Forwarding Procedure

Step1:RRC connection Break

Source eNodeB

Step2: source eNodeB implement DL data buffering

Source eNodeBS-GW

Buffering

Step3: Buffer forwarding to target cell

Source eNodeB

Target eNodeB

Data forwarding

Step4: Random access to target cell

Target eNodeB

DL data

Page104

Attention: There are several scenario introduced in the notes


IRAT Handover Execution Policy

LTE PS 2G/3G PS

PS handover

LTE VOIP 2G/3G CS

SRVCC

LTE PS

CCO/NACC

GSM Idle Mode

•IRAT Handover Execution Policy Priority:

PS handover > SRVCC > CCO(GSM ONLY) > Redirection

Page105

LTE Connection Mode

Redirection

2G/3G

RRC Connection Release

Access Procedure


Data Configuration of Handover Execution Policy The LTE system is incapable of carrying CS services. If an E-

UTRAN UE needs to start a mobile-originated or mobile-

terminated CS service, the UE will be moved to another RAT by

means of CSFB.

Page106






1.4 Redirection

1.5 Blind Handover






Contents1.9 IRAT Signaling Procedure in Connection

Mode

1.9.1 PS Handover for LTE <->G/U

1.9.2 RRC Release & Redirection for LTE <->G/U

1.9.3 eNACC for LTE->GERAN

1.9.4 CCO for GERAN->LTE

Mainly focus on the Gn/Gp SGSN


PS Handover LTE->GERAN/UTRAN Overview The UE in connected mode is handed over to a

GERAN/UTRAN cell after the UE moves from the area

covered by both the LTE network and GERAN/UTRAN to

the area covered only by the GERAN/UTRAN to ensure the

continuity of PS services.

Page109

SGW PGW

MMELTE

eNodeB

GSM /UMTS BTS

BSC/RNC SGSN GGSN

① HO decision: LTE to GU

eNodeB sends HO request

② MME sends relocation to target SGSN

Target GU network establish access connection

③ HO command is sent to UE

④ MS detected by target GU network

⑥ Release source network resources

⑤ Target network finish relocation.

Context exchange with source PGW

①

②

②

②

③③

④⑤

⑤

⑤

⑤⑥

⑥

HO Trigger, Measurement and Decision


Target RNC

Source eNodeB Old MME

New Gn/Gp SGSN

P-GW

3. Forward Relocation Request

4. Relocation Request

2. Handover Required

8. Handover Command

5. Forward Relocation Response

4. Relocation Request Acknowledge

12. Relocation Detect

MS

13. RRC message

1. Decision to perform handover to UTRAN

MS detected by target RNC

Establishment of Radio Access Bearers

9. Forwarding of data

14. Relocation Complete

15. Forward Relocation Complete

17. Routeing Area Update

16. Update PDP Context Request

18b. Release Resources

16. Update PDP Context Response

15. Forward Relocation Complete Acknowledge

C3

C2

10. HO from E-UTRAN Command

Serving GW

18. Delete Session Request

18a. Delete Session Response

6. Create Indirect Data Forwarding Tunnel Request

7. Create Indirect Data Forwarding Tunnel Response

PS HO(LTE->UMTS) – Gn/Gp SGSN

Page110


PS HO(LTE->GERAN) – Gn/Gp SGSN Preparation phase (Almost the same with that of LTE->UMTS except for

some signaling message name )

Page112

UE

Source eNodeB Target BSS Source MME New SGSN Serving GW HSS

1. Handover Initiation 2. Handover Required


4. PS Handover Request

7. PS Handover Request Acknowledge


PDN GW

Uplink and Downlink User Plane PDUs

5. Reservation of radio resources in target BSS

6. Target BSS creates the Target BSS to Source BSS Transparent Container


UE

Source eNodeB Target BSS Source MME New SGSN Serving GW HSS

PDN GW


1. Handover Command

2. HO from E-UTRAN Command

Sending of uplink data possible

4. GERAN A/Gb Access Procedures

5. XID Response

6. PS Handover Complete


8a. Forward Relocation Complete Acknowledge

9. Update PDP Context Request

11. Update PDP Context Response


7. XID Response

12. XID Negotioation for LLC ADM

12a. SABM UA exchange re-establishment and XID negotiation for LLC ABM)

Downlink User Plane PDUs

Forwarding of data

13. Routing Area Update procedure

14b. Release Resource 14. Delete Session Request

14a. Delete Session Response

PS HO(LTE-> GERAN) – Gn/Gp SGSN

Page113

Execution phase (Almost the same

with that of LTE->UMTS except for

some signaling message name )


PS HO(GERAN/UTRAN->LTE) – Gn/Gp SGSN The UE in connected mode is handed over to an LTE

cell after the UE moves from the area covered only

by the GERAN/UTRAN to the area covered by both

the LTE network and GERAN/UTRAN to ensure the

continuity of PS services.

Page114


PS HO(UTRAN->LTE) – Gn/Gp SGSN

Page115

Target eNodeB

Source RNC

Old Gn/Gp SGSN

New MME S-GW


6. Handover Request

2. Relocation Required

11. Relocation Command


7. Handover Request Acknowledge

MS

14. Forward SRNS Context 14. Forward SRNS Context

13. RRC message

15. HO to EUTRAN Complete

MS detected by target RNC

Establishment of Radio Access Bearers

C1

12. Forwarding of data

14. Forward SRNS Context Acknowledge

15. Handover Notify


17. Modify Bearer Request 20 Iu Release Command

20a. Iu Release Complete

19. Modify Bearer Response


18. Modify Bearer Request/Response

P-GW

4. Create Session Request

5. Create Session Response

1. Decision to handover

HSS

22. Procedure as in TS 23.401, steps 2 to 7 of Figure 5.4.2.2-1

21. Tracking Area Update procedure

8. Create Indirect Data Forwarding Tunnel Request

9. Create Indirect Data Forwarding Tunnel Response

23. Delete Indirect Data Forwarding Tunnel Request

23a. Delete Indirect Data Forwarding Tunnel Response


PS HO(GERAN->LTE) – Gn/Gp SGSN

Preparation phase

Page117

UE

Source BSS

Target eNodeB Old

SGSN Target MME Serving GW HSS

1. Handover Initiation

2. PS Handover Required


5. Handover Request

5a. Handover Request Acknowledge


PDN GW


4. Create Session Request

4a. Create Session Response


Serving GW UE Source BSS

Target eNodeB Old SGSN Target MME HSS

PDN GW


1. PS HO Required Acknowledge

2. PS Handover Command

Sending of uplink data possible

4. E-UTRAN Access Procedures

3. Forward SRNS Context

3a. Forward SRNS Context Ack

5. HO to E-UTRAN Complete 6. Handover Notify



11. BSS Packet Flow Delete Procedure


Forwarding of data

8 . Modify Bearer Request

10. Modify Bearer Response

(A)

9. Modify Bearer Request

9a. Modify Bearer Response

12. Tracking Area Update procedure

13. Procedure as in TS 23.401, steps 2 to 7 of Figure 5.4.2.2-1

PS HO(GERAN->LTE) – Gn/Gp SGSN Execution phase

Page118



Mode







LTE->G/U RRC Release & Redirection Overview

When the UE in connected mode moves from the area

covered by both the LTE network and UTRAN(or GERAN)

to the area covered by only the UTRAN, the UE needs to

be handed over to the UTRAN to ensure the continuity

of PS services. . The eNodeB obtains the UE

capability and knows that the UE does not

support either PS handover or CCO(for GERAN).

The eNodeB instructs the UE to reselect the target cell

in RRC release & redirection mode.

Page120


LTE->G/U RRC Release & Redirection Procedure

Page121

SGW PGW

MMELTE

eNodeB

GSM /UMTS BTS

BSC SGSN GGSN ① UE send target cell measurement to

eNodeB. eNodeB makes HO decision

② eNodeB send RRC Release message to UE, carrying RedirectedCarrierInfo that specifies the frequency of the target GERAN/UTRAN cell.

③ UE in RRC IDLE state, reselect the GERAN/UTRAN cell with the specified frequency according to redirection information.

eNodeB requests MME release LTE RRC_Connect.

UE initiates an RAU procedure.

②

③ ③

③

③

①


UE eNB RNC MME SGSN S/P-GW

2.Handover decision

4. UE reselect the target GERAN/UTRAN cell and launch RAU procedure

1. Measurement Report

3. RRC Connection Release


G/U->LTE RRC Release & Redirection Overview GERAN->LTE

The UE initiates a CSFB voice call in the area covered by both LTE and

GERAN and camps on the GERAN network. When the BSC releases the air

interface connection after the voice call is terminated, the released message

carries the Cell selection indicator after release of all TCH and SDCCH

parameter, which contains the information about the E-UTRAN cell (EARFCN

and PCI), instructing the UE to reselect to the LTE network.

UTRAN->LTE

The UE in connected mode is handed over to an LTE cell after the UE moves

from the area covered only by the UTRAN to the area covered by both the

LTE network and UTRAN to ensure the continuity of PS services. The RNC

obtains the UE capability and knows that the UE does not support the PS

handover. The eNodeB decides to instruct the UE to reselect the target cell in

RRC release + redirection mode.

Page122


G/U->LTE RRC Release & Redirection Procedure

Page123

UE RNC eNB MME SGSN S/P-GW

2.Handover decision

4. UE reselect the target E-UTRAN cell and launch TAU procedure


3. RRC Connection Release

UE BSC eNB MME SGSN S/P-GW

1. CS call terminated

3. UE reselect the target E-UTRAN cell and launch TAU procedure

2. Channel Release

UTRAN->LTE

GERAN->LTE



Mode







eNACC from the LTE to the GERAN Overview When the UE in connected mode moves out of the

area covered by both the LTE network and the

GERAN, if the target GERAN or UE does not support

the PS handover, the system message of the target

GERAN cell is sent to the UE on the source LTE

network. In this case, the duration of the UE

accessing the target GERAN cell is shortened to

reduce the service interruption duration.

Page125


eNACC LTE -> GERAN

Page126

10. Routing Area Update Procedure

UEServing

GWSource MME

Target SGSN

HSSPDN GW

Target BSS

Source-eNB

2.Handover decision


3. ENB Direct Information Transfer

4. RAN Information Request

5. RAN Information Request

6. RAN Information

7. RAN Information

8. MME Direct Information Transfer

9. Mobility From EUTRA Command

SGW PGW

MMELTE

eNodeB

GSM BTS

BSC SGSN GGSN

① UE send target cell measurement to eNodeB. eNodeB makes HO decision

② eNodeB gets target cell info. by RIM procedure

③ eNodeB sends HO command to UE

④ MS detected by target GSM network

⑥ MME release source network resources

⑤ Target network finish relocation.

Context exchange with source PGW

②

②

②③

④

⑤⑤

⑤

⑤⑥

⑥

①




Mode







CCO from the GERAN to the LTE Overview After the UE in connected mode moves from the area

covered by only the GERAN to the area covered by

both the LTE network and the GERAN, if the GERAN or

UE does not support the PS handover, the BSC

initiates the NACC procedure to obtain the system

message of the target E-UTRAN and informs the UE

about the message. In this case, the duration of the

UE accessing the target E-UTRAN cell is shortened to

reduce the interruption duration is reduced.

Page128


CCO from the GERAN to the LTE

Page129

10.Tracking Area Update Procedure

UE Source SGSN Target MME HSSPDN GWTarget eNB


Source-BSC

9. PACKET CELL CHANGE ORDER

2.Handover decision

3. RAN INFORMATION REQUEST 4. RAN INFORMATION

RELAY

5. MME DIRECT INFORMATION

TRANSFER

6. ENB DIRECT INFORMATION

TRANSFER7. RAN INFORMATION

RELAY8. RAN INFORMATION


Contents




LTE Voice Solution

From a technological perspective, there are two

standard solutions to provide CS services for E-

UTRAN UEs:

Page131

Voice Solution

Voice over IMS

CSFB

IMS required Rich VoIP service experience Fast connection Required SRVCC handover support

Fast supply voice service for LTE userMake full utilization of inherited CS network, fast deployment Large delay


Network Architecture & Functionality for CSFB to UTRAN/GERAN

Page132

•Deriving a VLR number and LAI from the TAI of the current cell, or using a default VLR number and LAI.•Maintaining SGs association with MSC/VLR for EPS/IMSI Attached UE•Triggering paging to eNodeB (when MSC-S pages the UE)•Initiating IMSI Detach at EPS Detach

S1-MME

S1-U

S11

E-UTRAN

MME

S-GW

S5

SGSN

HSS/HLR

S6a

S4

S3

S12

Iu-ps

Gb

PDN-GW

SGi

S7

MSC/VLR

A

Iu-cs

Gr

SGs

G/U/L handset

•Multi-mode G/U/L•CSFB capable•Support of procedures: Combined EPS/IMSI Attach, Update, Detach.

GERAN

UTRAN

•Need to be R8 ready•Maintaining SGs association with MME

•Forwarding paging request for CS domain to the UE.•Directing the UE to the target CS capable cell. (PS HO/redirection with or without SIBs).

C/D

PCRF

Rx

Internet / intranet / Operators & 3rd

Party Applications

Gs

for the mobility management and paging procedures between EPS and CS domain.


Contents



2.1 CSFB at the eNodeB

2.2 End-to-End Procedures for CSFB

2.3 SRVCC Procedure


CSFB mechanisms

include PS

redirection, PS

handover, and

CCO/NACC. No

matter which CSFB

mechanism is

adopted, both

measurement-

based handover

and blind handover

are applicable.

CSFB Procedure at the eNodeB

Page134

Star

The eNodeB receives a CSFB Indicator from the MME

Are the conditions for initiating a blind HO met?

The eNodeB delivers measurement configurations to the UE

The eNodeB makes a CSFB decision

No

Yes

The eNodeB exectes a CSFB decision

End

Execution phase

Decision phase

Measurement phase

Triggering phase


CSFB Triggering Principle(1/3) After a UE initiates a CS service in an E-UTRAN cell, the MME

sends the eNodeB an S1-AP Request message that contains a

CSFB Indicator, notifying the eNodeB that the UE should be

transferred to the target networks which are specified by the

ENodeBAlgoSwitch.HoAlgoSwitch parameter.

Page135


Choosing Between a Blind HO and a Measurement-based

HO

CSFB Triggering Principle(2/3)

Page136

Star

Triggering the RAT measurement

ENodeBAlgoSwitch.BlindHoSwitch is

enabled ?No

Yes

The UE supports certain RAT measurement ?

No

Yes

Blind Redirection Blind CSFB


CSFB Triggering Principle(3/3) - Blind CSFB Overview

In case of Blind HO(or redirection) , eNodeB decides

the CSFB target based on:

Blind handover priority of the target RAT:

InterRatHighestPri, InterRatSecondPri, and

InterRatLowestPri

Blind handover priority of the specific cell:

BlindHoPriority

LAI information ( R10 feature)

Page137


1. The eNodeB selects a RAT with the highest blind-handover

priority.

Data Configuration of Blind CSFB

Page138


Data Configuration of Blind CSFB(1/2)

2. The eNodeB selects a cell with the highest blind-handover

priority in this RAT

Page139

UTRAN

GERAN

0~32

0~32


Measurement Phase – Measurement Based CSFB Overview

In case of measurement based CS Fallback, eNodeB

sends the UE the measurement configuration,

include :

RAT type

Frequencies

CSFB B1 parameters

Page140

The measurement configuration related with both should be that the UE is capable of measuring


Measurement Phase – Measurement Report Configuration

In Measurement, CSFB is triggered by event B1:

Entering condition: Mn + Ofn - Hys > Thresh

Leaving condition: Mn + Ofn + Hys < Thresh

The B1 thresholds are different from those of

handover:

CS FallbackHoUtranB1ThdRscp

CS FallbackHoUtranB1ThdEcn0

CS FallbackHoGeranB1Thd

Page141


Measurement Phase – Event B1 Threshold

Configuration of CSFB event B1 threshold:

Page142


Decision Phase – Target Selection

In the decision phase of a measurement-based

handover, the eNodeB determines target cell based

on:

Evaluation of measurement report

LAI priority ( R10 feature)

Page143


LAI based CSFB (R10)

Priority to select target GU cells with same LAC as UE registered in GU NW during CSFB to avoid LAU (0.5s~3s).

Support national Roaming UE to select suitable fallback RAT/Cell bases on LAI Indicator among multi-PLMNs.

Page144

TA3/LA1

TAI/LAI

MME

LTE CoreLTE Core

GUL

GUL

GUL

TA1/LA1

TA2/LA2

Select same LA to CSFB

CSFB to LA1


PS HO based CSFB

The UE sends measurement reports to the eNodeB

The eNodeB delivers B1 measurement configuration to the UE

Execution Phase - CSFB to GERAN

Page145

Star

ENodeBAlgoSwitch.BlindHoSwitch is enabled ?

No

Yes

Does the UE support B1 measurement ?

No

Yes

CCO/NACC based CSFB Flash CSFB

The eNodeB receives a CSFB indicator from MME

Is PS handover enabled?

Does the UE support PS HO?

CCO/NACC Switch=ON ?

Flash CSFB Switch=ON ?

Does the UE support PS HO?No The UE supports Rel.9 RRC

with SIB & eNodB has stored target cells’ SI ?

Redirection based CSFB

No No No

Yes

Yes

Yes

Yes

NoNo


Execution Phase - CSFB to UTRAN

Page146

PS HO based CSFB

The UE sends measurement reports to the eNodeB

The eNodeB delivers B1 measurement configuration to the UE

Star

ENodeBAlgoSwitch.BlindHoSwitch is enabled ?

No

Yes

Does the UE support B1 measurement ?

No

Yes

Flash CSFB

The eNodeB receives a CSFB indicator from MME

Is PS handover enabled?

Does the UE support PS HO?

Flash CSFB Switch=ON ?

No The UE supports Rel.9 RRC with SIB & eNodB has stored

target cells’ SI ?Redirection based CSFB

No No

Yes

Yes

No


Flash CSFB (Redirection Based on R9)

To support Flash CS Fallback,

eNodeB requires exchange

information between E-

UTRAN and GERAN/UTRAN

through the core networks.

Saving 1s for UMTS compare

with R8 CSFB

Saving 2s for GSM compare

with R8 CSFB

Page147

UTRAN/GERAN EUTRAN

SGSN

GSM/UMTS Core

MME

LTE Core

RIM

Re

qu

es

t

RIM

Re

sp

on

se


RIM Configuration


Contents





2.3 SRVCC Procedure


Mechanisms of CSFB

Mechanism Supported RAT

Impact on Network

CS Access Delay

Based on PS handover

UTRAN/GERAN

Complex Short

Based on Redirection

UTRAN/GERAN/CDMA2000

Simple Long

Flash CSFB (Redirection with RIM)

UTRAN/GERAN

Medium Short

CSFB based on CCO/NACC

GERAN Medium Medium

Page150


Combined EPS/IMSI Attach Procedure

Page151


Contents





2.2.1 CSFB to UTRAN

2.2.2 CSFB to GERAN

2.3 SRVCC Procedure


CSFB to UTRAN

Based on the capabilities of UEs and networks, the

following mechanisms are available for an eNodeB to

perform CSFB to UTRAN

CSFB based on PS redirection for MOC(Mobile-Originated

Calls)

Flash CS Fallback

CSFB based on PS handover for MOC(Mobile-Originated

Calls)

CSFB to UTRAN Procedure for MTC (Mobile-Terminated Calls)


(Flash)CSFB to UTRAN based on PS Redirection for MOC

Page155

MMERNCeNodeBUE MSC SGSN

2.S1-AP Message with CS Fallback Indicator

1.Extended Service Request (containing a CS Fallback Indicator)

S1-AP Reponse Message

3.Optional measurement report

5. LAU, combined RAU/LAU, or RAU and LAU

6.CS call establishment procedure

S1 UE context release

4. RRC Connection Release with UTRAN frequency

For flash CSFB: RRC Connection Release with

UTRAN frequency/cell IDs/cell system information


S1 Message Tracing

Page156


CSFB to UTRAN Procedure for MTC

PS redirection

and PS handover

are the same for

MTO.

Page160


MMERNCeNodeBUE MSC SGSN

Handover Command

1. Extended Service Request (containing a CS Fallback Indicator)

Handover Command

S1-AP Response Message

3. Optional measurement report

4. PS handover preparation phase

5.CS call establishment procedure with LAU or combined RAU/LAU

6.PS handover execution phase

2. S1-AP Message (containing a CS Fallback Indicator)

PS handover procedure

CSFB to UTRAN based on PS HO for MOC

Page161

The eNodeB selects a fallback mechanism and a target cell using the CSFB algorithm. For details, see chapter 4 4.1 CSFB at the eNodeB.


Contents





2.2.1 CSFB to UTRAN

2.2.2 CSFB to GERAN

2.3 SRVCC Procedure


CSFB to GERAN Based on the capabilities of UEs and networks, the following

mechanisms are available for an eNodeB to perform CSFB to

GERAN

CSFB based on PS redirection for MOC

Flash CSFB (New introduced in eRAN3.0)

CSFB based on PS handover for MOC

CSFB based on CCO/NACC for MOC

CCO is short for “cell change order”

NACC is short for “network assistant cell change”

CSFB to GERAN Procedure for MTC is the same to that of CSFB to

UTRAN


(Flash)CSFB to GERAN based on PS Redirection for MOC

Page164

MMEBSCeNodeBUE MSC SGSN

2.S1-AP Message with CS Fallback Indicator


S1-AP Reponse Message


5. LAU, combined RAU/LAU, or RAU and LAU


S1 UE context release

4. RRC Connection Release with GERAN frequency group

6. Suspend

For flash CSFB: RRC Connection Release with

UTRAN frequency/PCIs/cell system information

Completely similar with that of (Flash)CSFB to UTRAN except the points in italic and red with underline


MMEBSCeNodeBUE MSC SGSN

Handover Command

1. Extended Service Request (containing a CS Fallback Indicator)

Handover Command


3. Optional measurement report

4. PS handover preparation phase

5.CS call establishment procedure with LAU or combined RAU/LAU

6.PS handover execution phase

2. S1-AP Message (containing a CS Fallback Indicator)

PS handover procedure

4b. Suspend

SGWPGW

UpdateBearers

CSFB to GERAN based on PS HO for MOC

Page165

The eNodeB selects a fallback mechanism and a target cell using the CSFB algorithm. For details, see chapter 4 4.1 CSFB at the eNodeB.


CSFB Based on CCO/NACC(GERAN)

Page166

BSC MSC SGSN

4. MobilityFromEUTRACommand (CCO optionally with NACC)

2.S1-AP Message (containing a CS Fallback Indicator)




6.Suspend

5.LAU, combined RAU/LAU, or RAU and LAU


8. S1 UE context release

MMEUE eNodeB


Contents





2.3 SRVCC Procedure


LTE – GSM/UMTS SRVCC Flow

Page168


Summary

Page170

GUL Interoperability procedure

GUL Interoperability scenarios

GUL Interoperability algorithm principles and data

configuration related


Appendix 1: Subscriber Identity Mapping The mappings are described briefly as follows slides.

For the details on the mappings between the

Globally Unique Temporary Identity (GUTI), RAI,

PTMSI, and PTMSI signature when the UE performs

GUL interworking, see sections 2.8.2.1 and 2.8.2.1 of

3GPP TS23.003.

Page171


Appendix 1: Mapping from a GUTI to an RAI, and P-TMSI Signature

RAI Component Mapping Data SourceMCC MCC in the GUTIMNC MNC in the GUTILAC MME Group IDRAC MME Code

Page172

GUTI-to-RAI mappings

P-TMSI Component Mapping Data Source31 to 30 11Bits 29 to 24 Bits 29 to the M-TMSIBits 23 to 16 MME CODEBits 15 to 0 Bits 15 to the M-TMSIP-TMSI Signature Bits 23 to the M-TMSI

GUTI-to-P-TMSI mappings


Appendix 1: Mapping from P-TMSI/RAI to GUTI

GUTI Component Mapping Data SourceMCC MCC in the RAIMNC MNC in the RAIMME Group ID LAC in the RAI

MME Code Bits 23 to 16 of the P-TMSI, namely higher-order 8 bits of the NRI

M-TMSI (bits 31 to 30) 11M-TMSI (bits 29 to 24) Bits 29 to the P-TMSIM-TMSI (bits 23 to 16) RAC in the RAIM-TMSI (bits 15 to 0) Bits 15 to the P-TMSI

Page173

Mapping of P-TMSI/RAI to GUTI

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Documents

LTE Interoperability in Connection Mode (LTE-GU)