telkomsel lte fdd interworking strategy_v1 1 1 - 20150126

HUAWEI TECHNOLOGIES Co., Ltd.

www.huawei.com

Telkomsel LTE Interworking Strategy

(LTE900 + UMTS + GSM)

Huawei confidential

HUAWEI TECHNOLOGIES CO., LTD. Confidential

Document Revision Record

Date Version Description Remark Author

22/8/2014 1.0 Initial Version Yeoh Yee Chin (HW)

25/01/2015 1.1.1 Put all key parameters involved into the documentRemove G900 from L to G mobility since GSM900 only remain S1/1/1 after refarming for L900

Sam Huang (HW)

Remark:

1. All the parameters and MML commands in this document are based on eRAN6.02. Parameters may require fine tune according to live network environment during optimization stage


Overview of Interworking StrategyIdle Mode

• L900 L900: Intra-frequency reselection based on coverage• L900 U2100/G1800: Reselection based on coverage (G900 not involved since only S1/1/1)• U2100/G1800/G900 L900: Reselection based on priority

Coverage Trigger

Priority Trigger

L900LTE 900 LTE 900

Cell CCell BCell A

UMTS 2100 UMTS 2100 UMTS 2100

UMTS 2100 UMTS 2100

GSM 900

F1 U2100

F2 U2100

F3 U2100

GSM 1800


G1800

GSM 900 GSM 900

GSM 1800 GSM 1800

G900


Overview of Interworking StrategyConnected Mode

• L900 L900: Intra-frequency handover based on coverage• L900 U2100/G1800: Inter-RAT PS Redirection for PS service, CSFB by redirection for CS

service (G900 not involved since only S1/1/1)• U2100/G1800/G900 L900: Redirection for PS Service (fast return only co-locate with LTE)

L900LTE 900 LTE 900

Cell CCell BCell A


UMTS 2100 UMTS 2100

F1 U2100

F2 U2100

F3 U2100


G1800GSM 1800 GSM 1800GSM 1800

Coverage Based

U->L Fast Return (>=SRAN8.0)

CSFB

G->L Fast Return (>=SRAN7.0)

GSM 900 GSM 900GSM 900 G900

Content Idle mode reselection strategy Connection mode mobility strategy CSFB


LTE<->LTE Intra-Freq – Idle Mode Cell Reselection

• Intra-frequency cell reselection is triggered when UE moves out of the serving cell coverage area.

• UE starts intra-frequency measurements if: SServingCell ≤ SIntraSearch

• Condition of cell-ranking for the serving cell and neighboring cells: Rs = Qmeas,s + Qhyst

Rn = Qmeas,n – CellQoffset

• Condition of cell reselection: The new cell is ranked higher than the serving cell, Rn > Rs for a time period of TReselEutran. The UE has camped on the serving cell for more than 1second.

L900LTE

900

LTE

900

LTE

900

Cell CCell BCell A

Coverage Trigger

RS

RP

Time

QRxLevMin

-128dBm

TReselEutran

Trigger cell reselection

Qmeas,s

Qmeas,n

Qmeas,s+Qhyst

●- 70dBm

SIntraSearch

Rn > Rs


LTE<->LTE Intra-Freq – Idle Mode Cell ReselectionLTE Parameter MML

Command Default value Recommend value Comments

SIntraSearchCfgInd

MOD CELLRESEL

CFGRange: NOT_CFG,

CFG

CFG (configure)

Enable the measurement triggering threshold for intra-frequency cell search

SIntraSearch 29

Range: 0~31Unit: 2dB

29 [2dB](-70dBm)

Measurement triggering threshold for intra-frequency cell reselectionAbsolute value = 2*QRxLevMin + 2*SIntraSearch (=2*-64 + 2*29 = -128+58= -70dBm)

Qhyst4

Range: 0~24Unit:dB

DB4_Q_HYST Hysteresis value for ranking criteria

QRxLevMin -64

Range: -70~-22Unit: 2dBm

-64 [2dBm] (-128dBm) Minimum required RSRP level

TReselEutran1

Range: 0~7Unit: s

1 [s] Timer value for EUTRAN cell reselection

QRxLevMin MOD CELLSEL-64


-64 [2dBm] (-128dBm)

Minimum required RSRP level for the cell to become a candidate for cell selection


Inter-RAT – Idle Mode Cell Reselection• Propose to set L900 to higher reselection priority than U2100 & GSM1800/900.

• LTE capable UE always prefer to camp on LTE due to higher cell priority than UMTS/GSM.

• UE performs cell reselection to F1 U2100 only when LTE signal is low and UMTS signal fulfill the cell reselection triggering threshold.

• Absolute priority will be set for both LTE and UMTS network to facilitate cell reselection preference to LTE network. It is not possible to set the same priority for LTE and UMTS network. Absolute priority is broadcasted in the SIB message and it affects cell reselection process.

• Absolute priority ranges from 0 to 7, where 7 indicate the highest priority and 0 indicate the lowest priority.

PriorityTelkomsel

System

7

6 LTE

5

4 UMTS

3

2

1 GSM

0Range use for GSM

Range use for UMTS

Range use for LTE/Future Use


Inter-RAT – Idle Mode Cell Reselection

Reselection from L900 to U2100 Lower Priority Cell

• UE starts inter-RAT measurements if : SServingCell ≤ SNonIntraSearch

• UE performs cell reselection to U2100 lower priority inter-RAT cell when all the following conditions are met: No cell meets the criteria for reselection to higher priority cells SServingCell < Threshserving,Low for a time period of TReselUTRAN. SNonServingCell,x > Threshx,Low for a time period of TReselUTRAN. The UE has camped on the serving cell for more than 1second.

RS

RP

Time

QRxLevMin

-128dBm

TReselUTRAN


SServingCell

LTE

SNonServingCell,x

U2100 (RSCP)

- 114dBm SNonIntraSearch

- 114dBm

- 103dBm ●

Threshserving,Low

Threshx,Low


Inter-RAT – Idle Mode Cell Reselection

Reselection from U2100 to L900 Higher Priority Cell

• If different reselection priority are set for different LTE frequency, then UE will search for the highest priority frequency, if no suitable cell then select second priority frequency.

• UE performs cell reselection to a higher priority inter-frequency cell when all the following conditions are met: SNonServingCell,x > ThdToHigh for a time period of TResel. The UE has camped on the serving cell for more than 1second.

RS

RP

Time

QRxLevMin

-128dBm

TResel


SServingCell

U2100

SNonServingCell,x

L900

- 110dBm ● ThdToHigh


LTE Parameter MML Command

Default value

Recommend value Comments

CellReselPriority

MOD CELLRESEL

1Range: 0~7 6 for L900 Cell reselection priority of the serving frequency. L900 has

higher priority than U2100.

SNonIntraSearchCfgInd

CFGRange:

NOT_CFG, CFG

CFG (configure)

Enable the measurement triggering threshold for inter-frequency or inter-RAT cell reselection

SNonIntraSearch

10Range: 0~31

Unit: 2dB

7 [2dB](-114dBm)

Measurement triggering threshold for inter-frequency or inter-RAT cell searchAbsolute value = 2*QRxLevMin + 2*SNonIntraSearch (=2*-64+2*7 = -128+ 14= -114dBm)

ThreshServLow

10Range: 0~31

Unit: 2dB

7 [2dB](-114dBm)

Triggering threshold for inter-frequency or inter-RAT cell reselection to a cell on lower priority frequencyAbsolute value = 2*QRxLevMin + 2*ThreshServLow (=2*-64+2*7 = -128 + 14= -114dBm)

QRxLevMin MOD CELLSEL

-64Range: -70~-22

Unit: 2dBm

-64 [2dBm] (-128dBm)

Minimum required RSRP level for the LTE cell to become a candidate for cell selection

LTE -> UMTS Inter-RAT – Idle Mode Cell Reselection (1/2)

Sam

e as

set

ting

in

Intr

a-F

req

rese

lect

ion


LTE Parameter MML Command Default value Recommend value Comments

CellReselPriorityCfgInd

ADD UTRANNFREQ

NOT CFGRange:

NOT_CFG, CFG

CFG(configure) Enable the inter-RAT cell reselection priority

CellReselPriority 1Range: 0~7 4 for UMTS

Cell reselection priority of the neighboring UTRAN frequency. If reselection priority is not configured , UE won’t reselect to the 3G frequency from LTE.

ThreshXLow6


6 [2dB](-103dBm)

Minimum RSCP level required for neighboring UTRAN cell to become a candidate for reselection if the priority of the UTRAN frequency is lower than or equal to that of the serving frequencyAbsolute value = (2*QRxLevMin + 1) + 2*ThreshXLow [((2*-58+1)+2*6)= -115 + 12= -103dBm]

PmaxUTRAN33

Range: -50~33Unit: dBm

24 [dBm] Maximum allowed UE transmission power in UTRAN

QRxLevMin -58


-58 [2dBm] (-115dBm)

Minimum required RSCP levelAbsolute value = 2*QRxLevMin + 1(2*-58+1= -116+1= -115dBm)

TReselUTRANADD

CELLRESELUTRAN

1Range: 0~7

Unit: s1 [s]

Timer value for LTE to UTRAN cell reselection.Also this MML is to enable SIB6 broadcast (if don’t set this MML, then L2U reselection won’t trigger)

LTE -> UMTS Inter-RAT – Idle Mode Cell Reselection (2/2)

• For L->U reselection measurement, only RSCP is defined by 3GPP 36.304 in 5.2.4.5 (E-UTRAN Inter-frequency and inter-

RAT Cell Reselection criteria)• For LTE to UMTS reselection, no need to define LTE to UMTS neighbor relationship, only UMTS frequency, and priority

parameters are required for each LTE cell.


UMTS Parameter MML Command Default value Recommend value Comments

SET LICENSE

SETOBJECT=UMTS,

ISPRIMARYPLMN=YES,

FUNCTIONSWITCH5=UL_MOBILITY

_P1-1

Enable License for UMTS to LTE reselection.If license not available, then UMTS to LTE interworking will not working.

SPriority MOD UCELLSELRESEL

4 4 for U2100 U2100 has lower priority than L900

SibCfgBitMap ADD UCELLSIBSWITCH

SIB19-0 SIB19-1 Enable UTRAN send SIB19 messages to UE for UMTS to LTE reselection. If not enable, then UE won’t reselect to LTE in 3G.

NodeBProtclVer MOD UNODEB NA R9Set NodeB protocol version to R9. If lower than R8, then UMTS to LTE interworking feature will not working

NPriority

ADD UCELLNFREQPRIO

INFO

NARange: 0~7 6 LTE cell reselection priority, shall be higher than UMTS

ThdToHigh2


9 [2dB](-110dBm)

RSRP level required for LTE neighboring cell to become a candidate for reselection if the priority of the frequency is higher than that of the serving frequencyAbsolute value = 2*EQrxlevmin + 2*ThdToHigh (-128 +18= -110dbm)

EQrxlevmin-70


-64 [dBm](-128dBm)

Minimum required RSRP level for a LTE cell entering the judgment procedure.

EARFCN NA 3700 LTE 900 EARFCN

EMeasBW D6 D25 (5MHz) measurement bandwidth information common on the target frequency

UMTS -> LTE Inter-RAT – Idle Mode Cell Reselection

For 3G to LTE reselection, no need to define 3G to LTE neighbor relationship, only LTE frequency, bandwidth

and priority parameters are required for each UMTS cell.


LTE Parameter MML Command Default value Recommend

value Comments

CellReselPriorityCfgInd

ADD GERANNFREQ

GROUP

CFG CFG (configure) Enable the cell reselection priority configuration

CellReselPriority 1 1 for GSM1800/900 GERAN priority is the lowest

QRxLevMin0

Range: 0~45Unit: 2dBm

1 [2dB](-113dBm)

Minimum RSSI level to camp on GERAN2*QRxLevMin-min QRxLevMin(1*2 -115+= -113dBm)

ThreshXLow7


7 [2dB](-99dBm)

Rx signal level threshold used in reselection to neighboring cells on a lower priority GERAN frequency2*QRxLevMin+2*ThreshXLow (-113 + 7*2 = -99dBm)

BandIndicator NA GSM_dcs1800Indicate whether the GSM cell is DCS1800 or DCS1900 when BCCH is between 512 and 810

StartingArfcn NAGSM smallest

BCCHStart of GSM BCCH frequency

GeranVersion NA EDGE GSM Cell capability

TReselGeranADD

CELLRESELGERAN

1Range: 0~7

Unit: s1s Cell reselection duration of GERAN cell reselection

Also to enable LTE to GSM cell reselection.

GeranArfcnADD

GERANNFREQGROUPARFCN

NA GSM BCCHCreate record for every GSM BCCH, if number of GSM BCCH <= 31 then can define into one group

LTE -> GSM Inter-RAT – Idle Mode Cell Reselection


GERAN Parameter MML Command Default value


GERANPRI

SET GCELLPRIEUTRAN

SYS(All GERAN cells

within LTE coverage area need to set this

MML command)

1 (0~7) 1 Set reselection priority LTE > UMTS > GSM.

ThrUTRANHigh and UTRANQRxLevmin determine the threshold for UE reselect from 2G to 3G is: -103dBm +0dB = -103dBm, matching to existing 2G/3G reselection setting (-102dBm)

R7 and older UE won’t decode parameters in this command, and will follow existing 2G/3G reselection setting.For R8 and above UE, 2G/3G priority and threshold in this command will overwrite the existing 2G/3G reselection setting.So we must set UTRAN priority higher than GSM, to ensure R8 and above UE can reselect to UMTS as priority.

UTRANPri 1 (0~7) 4

EUTRANPRI 6 (0~7) 6

ThrUTRANHigh 200

(0*2dB=0dB)

ThrUTRANLow 200

(0*2dB=0dB)

UTRANQRXLevmin 98 (8*2-119 =

-103dBm)

EUTRANQRXLEVMIN

6(-78~-140)

6(-128dBm) Minimum RSRP level to camp on LTE

THREUTRANHIGH 20 (0~31) 9 [2dB](-110dBm)

If the measured RSRP value of one or more neighboring EUTRAN cells is higher than the value of this parameter, the MS is allowed to reselect a neighboring cell in EUTRAN whose priority is higher than the GERAN priority.

ThrPriSearch NA 15 Enable UE always search UMTS or LTE in idle mode

ThrEUTRANLow9

9 [2dB](-110dBm)

ThrGSMLow 0 15 Always search 3G or LTE signal when UE in GSM

QPEUTRAN 15 7 UE always search LTE signal when UE has PDP in GSM

HPRIO 0 1 (5dB)0 (∞), 1(5dB), 2 (4dB), 3 (3dB). Refer to 3GPP 45008 6.6.6 Algorithm for inter-RAT cell re-selection based on priority information

GSM -> LTE Inter-RAT – Idle Mode Cell Reselection (1/2)


GERAN Parameter MML Command Default value


EXTLTECELLIDADD

GEXTLTECELL

Dummy LTE cell can be defined, only

EARFCN and Duplexer

mode(FDD or TDD) will broadcast to UE

in SIB 2 quater

NA8048 and

above

Index of a LTE external cell, shall be unique within a 2G BSCTwo LTE dummy neighbor cells are defined in each GSM BSC for G to L reselection, 8048 for the L1800 layer, 8049 for L2600 layer.

FREQ NA 3700 LTE EARFCN

EUTRANTYPE NA FDD Indicate the LTE cell is TDD or FDD

SptResel ADD GLTENCELL NA SUPPORT Enable cell reselection to LTE cell.

LTECellReselENSET

GCELLHOBASICNo Yes To enable reselection from GSM to LTE

GSM -> LTE Inter-RAT – Idle Mode Cell Reselection (2/2)

All GSM cells within LTE coverage area need to enable GSM to LTE reselection. For GSM to LTE reselection, need to define at least one LTE neighbor for each LTE frequency for each GSM cell.

A dummy LTE neighbor for LTE900 could be defined in each GSM BSC to define G to L neighbor for G to L reselection.

Once G2L reselection is enabled, then G2U reselection will changed to “by priority” for R8 and above UE, then need to

mapping existing network G2U reselection parameters to parameters in MML “SET GCELLPRIEUTRANSYS”. And UTRANPri

must be set larger than GERANPri so UE will reselection to UMTS in idle mode.


Impact if enable GSM to LTE reselectionReselection to 3G might be longer for LTE compatible UE if LTE signal is not good enough

2 new SIB 2quater are introduced for 2G to LTE reselection, and each SIB will take 3~4S for UE

to receive. Only after UE receives all SIB 2quater the UE will start Inter-RAT measurement if 2G

is the lowest layer. Thus 2G to 3G reselection will be prolong, compare to that if 2G to LTE

reselection not introduced.

For R8 and above UE, normal 2G to UMTS reselection will be replaced by the “priority

reselection”

Need to set UMTS priority higher than 2G and lower than LTE to compatible with existing

“normal” 2G to 3G reselection criteria, and need to map the existing GSM to UMTS

reselection RSCP

From 3GPP 45008, 6.6.6 Algorithm for inter-RAT cell re-selection based on priority information:

……. (describe the priority based Inter-RAT reselection from 2G to 3G or LTE)

A UTRAN FDD cell shall only be reselected if, in addition to the criteria above, its measured Ec/No value is equal

to or greater than FDD_Qmin - FDD_Qmin_Offset.

So from above, we can see UE will evaluate both RSCP and Ec/Io before reselect to 3G

No impact to normal R7 and older UE (don’t support LTE) since they won’t decode the R8 SIB

R7 and older UE will perform G to U reselection based on existing “normal” reselection criteria


LTE Event for service in connection mode

Even

tMeaning Application

A1 Serving becomes better than threshold Quit Gap mode

A2 Serving becomes worse than thresholdEnter Gap mode for Inter-Freq or Inter-RAT

measurement, or trigger Blind Redirection

A3 Neighbor becomes offset better than serving Trigger Intra-Freq or Inter-Freq handover within LTE

A4 Neighbor becomes better than serving Trigger Inter-Freq handover within LTE

A5Serving becomes worse than threshold1 and

neighbor becomes better than threshold2Huawei not use A5 event

B1 Inter RAT neighbor becomes better than threshold Trigger Inter-RAT handover or redirection

B2Serving becomes worse than threshold1 and inter-

RAT neighbor becomes better than threshold2Huawei not use B2 event


LTE<->LTE Intra-Freq Handover• Intra-frequency handovers are triggered by event A3.

• When the signal quality in at least one intra-frequency neighboring cell meets the configured triggering condition of event A3, the UE sends the measurement result to the eNodeB.

• Event A3 entering condition: Mn + Ofn + Ocn – Hys > Ms + Ofs + Ocs + Off

• Event A3 leaving condition: Mn + Ofn + Ocn + Hys < Ms + Ofs + Ocs + Off

L900LTE

900

LTE

900

LTE

900

Cell CCell BCell A

Coverage

Based

Parameter Value Description

Mn N/A Obtained from UE’s RSRP Measurement of neighbouring intrafreq LTE cells

Ofn 0 Frequency specific offset of the frequency of the neighbour cell

Ocn 0 Cell specific offset of the neighbour cell

Hys 2 Hysteresis parameter for this event.Actual value = IE value * 0.5 (dB)

Ms N/A Obtained from UE’s RSRP Measurement of serving LTE cell

Ofs 0 Frequency specific offset of the serving frequency

Ocs 0 Cell specific offset of the serving cell

Off 2 Offset parameter for this event, i.e. a3-Offset.Actual value = IE value * 0.5 (dB)

RS

RP

Time

TimeToTrigger

Event A3 is triggered

Ms

Mn

●

Ofs+Ocs+Off

Ofn+Ocn-Hys


LTE<->LTE Intra-Freq HandoverLTE Parameter MML


IntraFreqHoA3Hyst

MOD INTRAFREQHOGROUP

2Range: 0~30Unit: 0.5dB

2(1dB) Intra-frequency handover hysteresis for event A3

IntraFreqHoA3Offset 2

Range: -30~30Unit: 0.5dB

2(1dB) Intra-frequency handover offset for event A3

IntraFreqHoA3TimeToTrig 320Range: 0~5120ms 320 [ms] Intra-frequency handover time-to-trigger for event A3

IntraFreqHoA3TrigQuan

MOD INTRARATH

OCOMM

RSRPRange: RSRP,

RSRQRSRP A3 measurement trigger quantity

IntraFreqHoA3RprtQuan

RSRPRange:

SAME_AS_TRIG_QUAN(Same as

Trig Quan)

RSRP A3 measurement report quantity

IntraFreqHoRprtInterval240

Range:120ms-60min

240 [ms] Intra-frequency measurement report interval


LTE -> UMTS/GSM (Inter-RAT by redirection)

Redirection Based on Measurement Redirection based on measurement uses the event A2 with measurement. Redirection is a simple IRAT policy, most of the UEs support it. The eNodeB doesn’t communicate with other NE, it just sends RRC_CONN_REL to redirect the

UE to U/G cell, then UE will start random access in the target cell. It’s the most compatible method for Inter-RAT mobility, since no need MME or SGSN involved

for handover preparation.

The UE starts the access procedure in U/G system, and trigger the RAU procedure

UE eNodeB RNC/BSCMeasurement Report of A2 Event

( Inter-RAT A2 Event with measurement )

Measurement Control for B1 Event( B1 Event for Inter-RAT Handover Based on Coverage )

Handover Decision

Measurement Report of B1 Event( B1 Event for Inter-RAT Handover Based on Coverage )

RRC_CONN_REL( Redirection Command containing the U/G Carrier Information)

Redirection Based

on Measurement


LTE -> UMTS Inter-RAT – PS Connected

• In a coverage-based inter-RAT redirection, event A2 triggers inter-RAT measurements: Entering condition: Ms + Hys < Thresh Leaving condition: Ms – Hys > Thresh

• In a coverage-based inter-RAT redirection, event A1 stops inter-RAT measurements: Entering condition: Ms – Hys > Thresh Leaving condition: Ms + Hys < Thresh

• The triggering of event B1 indicates that at least one neighboring cell signal quality is higher than specified threshold: Entering condition: Mn + Ofn – Hys > Thresh Leaving condition: Mn + Ofn + Hys < Thresh


Thresh -103 dBm Threshold for B1 event trigger

Mn N/A Obtained from UE Measurement

Ofn 0 Frequency specific offset of the frequency of the neighbour cell

Hys 2B1 Hysteresis。Actual value = IE value * 0.5 (dB)Actual value = 1 dB

InterRatHoUtranB1TimeToTrig

640 ms Time To Trigger


Ms N/A Obtained from UE Measurement. RSRP

Thresh -116 dBm (RSRP) Threshold for A2 event

Hys 4A1A2 Hysteresis.Actual value = IE value * 0.5 (dB)Actual value = 2 dB

InterFreqHoA1A2TimeToTrig 640 ms Time To Trigger


LTE -> UMTS Inter-RAT – PS Redirection (1/3)


HoModeSwitchMOD

ENODEBALGOSWITCH

UtranRedirectSwitch:Off

UtranRedirectSwitch:On Enable redirection from LTE to UTRAN switch

UtranPsHoSwitch:Off

UtranPsHoSwitch:Off Enable PS handover from LTE to UTRAN switch

InterRatHoA1A2TrigQuanMOD

INTERRATHOCOMM

RSRPRange: RSRP, RSRQ, BOTH

RSRP Inter-RAT A1/A2 measurement trigger quantity

InterRatHoUtranB1MeasQuan

UTRAN_RSCPRange: RSCP, ECN0, BOTH

RSCP UTRAN measurement trigger quantity

InterRatHoA1ThdRsrp

ADD INTERRATHOCO

MMGROUP

-111Range: -141~-

43Unit: dBm

-111 [dBm] RSRP threshold for inter-RAT measurement event A1

InterRatHoA2ThdRsrp

-115Range: -141~-

43Unit: dBm

-115 [dBm] RSRP threshold for inter-RAT measurement event A2

InterRatHoA1A2Hyst2

Range: 0~30Unit: 0.5dB

2(1dB) Hysteresis for inter-RAT measurement event A1/A2

InterRatHoA1A2TimeToTrig

640Range:

0ms~5120ms640 [ms] Time-to-trigger for inter-RAT measurement event A1/A2




InterRatHoUtranB1ThdRscp

ADD INTERRATHOUTRANGROUP

-103Range: -120~-25

Unit: dBm-103 [dBm] RSCP threshold for event B1 related to coverage-

based inter-RAT HO to UTRAN

InterRatHoUtranB1Hyst2

Range: -120~-25Unit: dBm

2 [0.5dB](1dB) Hysteresis for inter-RAT HO event B1

InterRatHoUtranB1TimeToTrig

640Range: 0ms-

5120ms640 [ms] Time-to-trigger for inter-RAT HO event B1




UtranCellId

ADD UTRANEXTERNAL

CELL

NA 3G Cell ID Cell ID of the external UTRAN cell.

UtranFddTddType UTRAN_FDD UTRAN_FDD Indicates the type of the UTRAN cell (FDD or TDD)

RncId NA 3G cell RNC ID RNC ID of the external UTRAN cell

RacCfgInd NOT_CFG CFGwhether to set the routing area code (RAC) of the external UTRAN cell. This parameter must be set to CFG if the external UTRAN cell supports packet switched (PS) services

Rac NA 3G cell RAC RAC of the UMTS cell

PScrambCode NA 3G cell PSC Downlink Primary Scrambling Code of the external UTRAN cell

Lac NA 3G cell LAC Location Area Code of the external UTRAN cell

BlindHoPriority ADD UTRANNCELL

0Range: 0~32

At least one 3G neighbor set priority > 0,

Other neighbor cells set to 0.

Configure one UTRAN (U2100 F1) dummy neighbor cell as blind handover neighboring cell to comply the UE that don’t support UTRAN measurement (larger BlindHoPriority value denotes higher priority).

At least one UMTS neighbor shall be configured with BlindHandoverPriority > 0 thus eNodeB could trigger blind redirection to the UMTS frequency.


LTE -> GSM Inter-RAT – PS Redirection (Algorithm Para.)


HoModeSwitch MOD

ENODEBALGOSWITCH

GeranRedirectSwitch-0

GeranRedirectSwitch-1 Enable Redirection to GERAN switch

GeranPsHoSwitch-0

GeranPsHoSwitch-0

Enable PS handover to GERAN switch only in future if UE support L2G HO

BlindHoSwitch-0

BlindHoSwitch-0

Disable blind handover switch, take L2G redirection based on measurement

InterRatHoGeranB1Thd

ADD INTERRATHOGER

ANGROUP

-95dBmRange: -110~-

48Unit: dBm

-95dBm RSSI threshold for event B1 that is used in HO to GERAN

InterRatHoGeranB1TimeToTrig

640msRange:

0ms~5120ms640ms Time to trigger for event B1 related to inter-RAT

handover to GERAN

InterRatGeranB1Hyst1dB

Range: 0~30Unit: 0.5dB

1dB Hysteresis for event B1 related to inter-RAT handover to GERAN


LTE -> GSM Inter-RAT – PS Redirection (L2G neighbor)

LTE Parameter MML Command Default value


GeranCellId

ADD GERANEXTERNALCE

LL

NA 2G Cell ID The 2G cell ID

Lac NA 2G Cell LAC LAC of the 2G cell

RacCfgInd NOT_CFG CFGwhether to set the routing area code (RAC) of the external GERAN cell. This parameter must be set to CFG if the external GERAN cell supports PS service

Rac NA 2G Cell RAC RAC of the GSM cell

BandIndicator NA GSM_DCS1800Indicate the GSM band is DCS1800 or DCS1900 when BCCH is between 512 and 810

GeranArfcn NA GSM BCCH BCCH of GSM Cell

NetworkColourCode NA 2G cell NCC NCC of the GSM cell

BaseStationColourCode NA 2G cell BCC BCC of the GSM Cell

BlindHoPriority ADD GERANNCELL

0Range: 0~32

At least one 3G neighbor set priority > 0,

Other neighbor cells set to 0.

Define the GSM external cell as the LTE cell neighbor. At least one GSM neighbor shall be configured with BlindHandoverPriority > 0, thus eNodeB could trigger blind redirection to GSM

eNodeB will send all the GERAN Arfcn list within the GeranNFreqGroup to UE within the RRC Connection release

message. UE will scan GSM cell and camp on a best cell to establish the connection.


CS Fallback (CSFB)

• CSFB (CS Fallback Function) is specified by ETSI TS 123 272 v10.6.0 and is a mandatory requirement which supports “traditional” CS voice in LTE networks prior to IMS (IP Multimedia Subsystem) deployment.

• In the overlaid coverage of LTE and UMTS, UMTS provides voice service for the multi-mode UE. When CSFB voice service is initiated, the LTE data service will be handed / redirected over to UMTS network.

• The benefit of having CSFB is that voice service can be deployed quickly reusing traditional UMTS core with no additional equipment, thus saving on cost and minimizing new investment.

• In addition, it also guarantees users data service continuity when re-direction or handover of the PS service occurs.


CSFB: Architecture and functionalities

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 procedures:

Combined EPS/IMSI

Attach, Update, Detach.

• 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

GERAN

UTRAN

• Need to be R8 ready• Maintaining SGs

association with

MME

• Forwarding paging request for CS domain to 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 mobility management and

paging procedure between

EPS and CS domain.

Doesn’t active ISR (Idle

mode Signaling

Reduction) during

combine RA/LA attach


CSFB – Mobile Originating Call ProcedureMobile Originating call in Active Mode


CSFB – Mobile Terminating Call Procedure

Mobile Terminating call in Active Mode Mobile Terminating call in Idle Mode


LTE -> UMTS Inter-RAT – CSFB by RedirectionLTE Parameter MML


HoAlgoSwitch MOD ENODEBALG

OSWITCH

UtranCsfbSwitch:Off UtranCsfbSwitch:On Enable CSFB to UTRAN switch

HoModeSwitch BlindHoSwitch:Off BlindHoSwitch:Off Enable blind HO switch to perform CSFB

CsfbHoUtranB1ThdRscp MOD

CSFALLBACKHO

-106Range: -120~-25

Unit: dBm-100 [dBm] RSCP threshold for event B1 that is used in CSFB

to UTRAN

CsfbHoUtranTimeToTrig

40Range:

0ms~5120ms40 [ms] Time-to-trigger for event B1 that is used in CSFB to

UTRAN

LTE -> GSM Inter-RAT – CSFB by Redirection


HoAlgoSwitch MOD ENODEBALGO

SWITCH

GeranCsfbSwitch:Off

GeranCsfbSwitch:On Enable CSFB to Geran switch

HoModeSwitch BlindHoSwitch:Off BlindHoSwitch:Off Enable blind HO switch to perform CSFB to Geran

CsfbHoGeranB1ThdMOD

CSFALLBACKHO

-95Range: -110~-48

Unit: dBm-95 [dBm] RSSI threshold for event B1 that is used in CSFB to

Geran

CsfbHoGeranTimeToTrig

320Range:

0ms~5120ms320 [ms] Time-to-trigger for event B1 that is used in CSFB to

Geran (Higher than Utran to do CSFB to Utran first)


Special setting in GSM to support CSFB


SUPPORTCSFB

SET GCELLSOFT

UNSUPPORT SUPPORTIf this parameter keep default value “unsupport”, then the MT call of CSFB will fail in GSM. For detail please refer to product specification.

CSFBPAGRSPBCSWITCH

NO

YES for MSC pool;

NO for none-MSC pool

Refer to product specification


UMTS -> LTE Fast ReturnUMTS Parameter MML Command Default value Recommend value Comments

FastReturnToLTESwitch

MOD UCELLHOCOMM(all carriers of the

UMTS cell which co-site with LTE)

HO_UMTS_TO_LTE_FAST_RETURN_S

WITCH=0

HO_UMTS_TO_LTE_FAST_RETURN_SWITCH=1 Enable UMTS to LTE Fast Return

FastReturnToLTESwitch

PERFENH_PS_FAST_RETURN_LTE_S

WITCH=0

PERFENH_PS_FAST_RETURN_LTE_SWITCH=1 Enable UMTS to LTE Fast Return

GSM ->LTE Fast ReturnGSM Parameter MML Command Default value Recommend value Comments

SPTRAPIDSEL

ADD GLTENCELL(only GSM cell

which co-site with LTE)

NOT_SUPPORT

Co-Loc with LTE: SUPPORT

NOT Co-loc with LTE: NOT_SUPPORT

Enable GSM to LTE Fast ReturnOnly enable for co-locate with LTE900 cells.

If enable fast return for GSM cell that not co-loc with LTE, then UE may fail to fast return to LTE in areas that LTE

coverage is poor, then UE will scan all supported LTE band then comeback to GSM, this will cause user lost service

(10~15S test by Huawei P1)

If enable fast return for UMTS cell that not co-loc with LTE, then UE may fail to fast return to LTE in areas that LTE

coverage is poor, then UE will scan all supported LTE band then comeback to UMTS, this will cause user lost service

(10~15S test by Huawei P1)

Since these 3G/2G cells that NOT Co-Loc with LTE cannot enable fast return to LTE, so when UE release CSFB

call under these cells, UE will stay in 3G/2G until background PS also released then can release back to LTE,

which prolong UE come back to LTE.

Thank youwww.huawei.com

telkomsel lte fdd interworking strategy_v1 1 1 - 20150126

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