Omantel 3G Handover to GSM Parameter Study Report

HUAWEI TECHNOLOGIES CO., LTD.

Omantel 3G handover to GSM Topic Report

HUAWEI TECHNOLOGIES CO., LTD. HUAWEI Confidential Page 2

The PI instruction for 3G handover to GSM(CS) IRATHO.AttRelocPrepOutCS; IRATHO.SuccRelocPrepOutCS;

IRATHO.AttOutCS; IRATHO.SuccOutCS;

INDEX

The parameters for 3G handover to GSM(CS)InterRatReportMode; InterRATFilterCoef; Hystfor2D; Hystfor2F;

InterRATPeriodReportInterval; HystforInterRAT; TrigTime2D;

TrigTime2F;InterRATCSThd2DEcN0;InterRATCSThd2FEcN0; InterRATCSThd2DRSCP;

InterRATCSThd2FRSCP; TargetRatCsThd; InterRATMeasTime;

CONTENTS


Measurement point

The measurement is triggered at point A B C D as shown in the picture:

The counter and PI instruction for 3G handover to GSM(CS)

IRATHO.AttRelocPrepOutCSWhen the RNC sends the CN a RELOCATION REQUIRED message as point A, this counter is measured in the best cell that the UE camps on. IRATHO.SuccRelocPrepOutCSWhen the RNC receives from the CN a RELOCATION COMMAND message as point B this counter is measured in the best cell that the UE camps on. IRATHO.AttOutCSWhen the RNC sends the UE a HANDOVER FROM UTRAN COMMAND message as point C, this counter is measured in the best cell that the UE camps on. IRATHO.SuccOutCSWhen the RNC receives an IU RELEASE COMMAND message with the cause value of "Successful Relocation" as point D, the outgoing handover succeeds and this counter is measured in the best cell that the UE camps on.

IRATHO.SuccRelocPrepOutCS.Cell.Rate = IRATHO.SuccRelocPrepOutCS / IRATHO.AttRelocPrepOutCS

IRATHO.SuccOutCS.Cell.Rate = IRATHO.SuccOutCS / IRATHO.AttOutCS


Kind of IRATHO

The counter and PI instruction for 3G handover to GSM(CS)

The causes for outgoing inter-RAT handover can be load, RF (coverage, QoS, or HCS), inter-RAT DRD, or service type. The cause inter-RAT DRD only exists in the inter-RAT CS handover.

VS.IRATHO.SuccRelocPrepOutCS.RF(VS.IRATHO.AttOutPS.TrigRscp, VS.IRATHO.AttOutCS.TrigEcNo)

VS.IRATHO.SuccRelocPrepOutCS.Load

VS.IRATHO.SuccRelocPrepOutCS.Service

Common failure

IRATHO.FailRelocPrepOutCS.NoResAvail -- No Resource Available

IRATHO.FailOutCS.CfgUnsupp -- Configuration Unsupported

IRATHO.FailRelocPrepOutCS.TgtFail -- Relocation Failure in Target CN/RNC or Target System

RATHO.FailOutCS.PhyChFail -- Physical Channel Failure

VS.IRATHO.FailOutCS.NoReply -- Timer Waiting out for Iu Release Command

VS.IRATHO.FailRelocPrepOutCS.ReqInfoNotAvail -- Requested Information Not Available

IRATHO.FailRelocPrepOutCS.HigherTrafficLod -- Traffic Load In The Target Cell Higher Than In The

Source Cell


The PI instruction for 3G handover to GSM(CS) IRATHO.AttRelocPrepOutCS; IRATHO.SuccRelocPrepOutCS;

IRATHO.AttOutCS; IRATHO.SuccOutCS;

INDEX

The parameters for 3G handover to GSM(CS) InterRatReportMode; InterRATFilterCoef; Hystfor2D; Hystfor2F;

InterRATPeriodReportInterval; HystforInterRAT; TrigTime2D; TrigTime2F;

InterRATCSThd2DEcN0; InterRATCSThd2FEcN0; InterRATCSThd2DRSCP;

InterRATCSThd2FRSCP; TargetRatCsThd; InterRATMeasTime;

CONTENTS


InterRatReportMode -- Inter-RAT measurement reporting mode:

EVENT_TRIGGER

To avoid the ping-pong effect before and after the inter-RAT handover, use event 3A as the triggering event

that determines the inter-RAT handover.

PERIODICAL_REPORTING

When the quality of the GSM cell reported by the UE meets the criteria for inter-RAT handover, the delay

trigger timer is started. If the quality of the GSM cell always meets the criteria for inter-RAT handover before

timeout, the inter-RAT handover is triggered after the delay trigger timer expires.

The parameters for 3G handover to GSM(CS)

The advantage of event-triggered reporting is that the signaling transmission and processing load are saved.

The ping-pong effect in handover is prevented to some extent by 3A. The drawback of event-triggered

reporting is that the event is reported only once and cannot be changed to periodical reporting.

The advantage of periodical reporting is that it can be used for repeated handover re-attempts on the same

cell when the handover fails. The drawback of periodical reporting is that it requires large amount of signaling

and increases the load on the UU interface and for signaling processing.

• Current netwrok setting(1st Oct): All cell be set to PERIODICAL_REPORTING


InterRATFilterCoef -- Inter-RAT Filter Coefficient


If this parameter is set to a greater value, the effect of smoothing signals and the ability of anti-fast-fading

improve. However, the ability of tracing the signal change becomes low and call drops are likely to occur

because handover is not performed in time.

If this parameter is set to a smaller value, the number of unnecessary handovers increases.

In cells where the average moving speed of UEs is low, there is a comparatively big shadow fading square

error. Therefore, the recommended value is 4. The value can be increased in a certain degree.

In cells where the average moving speed of UEs is medium, there is a comparatively smaller shadow fading

square error. Therefore, the recommended value is 3.

In cells where the average moving speed of UEs is high, there is a comparatively small shadow fading square

error. Therefore, the recommended value is 2.

GUI Value Range: D0, D1, D2, D3, D4, D5, D6, D7, D8, D9, D11, D13, D15, D17, D19Actual Value Range: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 19Unit: NoneDefault Value: NoneRecommended Value: D3• Current network setting(1st Oct): All cell be set to D3


InterRATPeriodReportInterval -- Period Reporting Interval


Interval that the UE reports inter-RAT measurement results to the RNC. This parameter specifies the

interval that the UE sends inter-RAT measurement results to the RNC in periodical reporting mode. The

GSM RSSI measurement period is 480 ms. Therefore, the inter-RAT periodical reporting interval should

be longer than 480 ms.

If the setting of this parameter has impact on the Uu signaling traffic. If the period is too short and the

reporting frequency is too high, the RNC may have high load in processing signaling.

If the period is too long, the network cannot detect the signal changes in time, which may delay the inter-RAT

handover and thus cause call drops.

GUI Value Range: NON_PERIODIC_REPORT(Non periodical reporting), D250~1 D500~2 D1000~3 D2000~4

D3000~5 D4000~6 D6000~7 D8000~8 D12000~9 D16000~10 D20000~11 D24000~12 D28000~13 D32000~14

D64000

Actual Value Range: NON_PERIODIC_REPORT, 250, 500, 1000, 2000, 3000, 4000, 6000, 8000, 12000, 16000,

20000, 24000, 28000, 32000, 64000

Unit: ms ; Default Value: None

Recommended Value: D1000

• Current netwrok setting(1st Oct): All cell be set to D1000


InterRATMeasTime -- Inter-RAT Measure Timer Length


Length of the timer for inter-RAT measurement. 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 (if activated) should be deactivated. The value 0 indicates that the inter-RAT

measurement timer is not started.

This parameter is designed to prevent that the UE being in compressed mode for a long time when the

handover criteria are not fulfilled. If the compressed mode is maintained for a long time, the service quality is

adversely affected and the total available capacity of the system decreases.

If the parameter is set to a smaller value, the UE cannot finish inter-RAT handover. If the parameter is set to a

larger value, the compressed mode will not be disabled, thus affecting UE measurement. Most inter-RAT

handovers can be finished within 60s.

GUI Value Range: 0~512

Actual Value Range: 0~512

Unit: s

Default Value: None

Recommended Value: 60

• Current netwrok setting(1st Oct): All cell be set to 60


TargetRatCsThd -- Inter-RAT CS Handover Decision THD


Quality requirement for the cell of another RAT during inter-RAT handover for CS domain services.

For CS services, if the value of "Inter-RAT Reporting Mode" is set to "EVENT_TRIGGER", this parameter

is used to set the criterion for triggering event 3A.

If the value of "Inter-RAT Reporting Mode" is set to "PERIODICAL_REPORTING", this parameter is used

for the assessment of inter-RAT coverage handover.

The setting of this parameter affects number of hard handovers. If this parameter is set to a smaller value,

hard handover is likely to be triggered, but ping-pong handover may occur. If this parameter is set to a greater

value, hard handover is unlikely to be triggered, but call drops may occur.


Actual Value Range: lower than -110, -110~-48(Actual value

meets the condition: Actual Value = GUI Value - 111)

Unit: dBm

Default Value: None


• Current netwrok setting(1st Oct): All cell be set to 16 (-95dBm)


InterRATCSThd2DEcN0 -- Inter-RAT CS Measure Start Ec/No THD

InterRATCSThd2FEcN0 -- Inter-RAT CS Measure Stop Ec/No THD


GUI Value Range: -24~0

Actual Value Range: -24~0

Unit: dB

Default Value: None

Recommended Value: -14

GUI Value Range: -24~0

Actual Value Range: -24~0

Unit: dB

Default Value: None


2D EC/N0value number of cell proportion-14dB 1909 72.42%-12dB 823 26.76%-10dB 30 0.81%

2F EC/N0value number of cell proportion-12dB 1909 73.01%-10dB 823 26.23%-8dB 30 0.76%


InterRATCSThd2DRSCP -- Inter-RAT CS Measure Start RSCP THD

InterRATCSThd2FRSCP -- Inter-RAT CS Measure Stop RSCP THD


GUI Value Range: -115~-25

Actual Value Range: -115~-25

Unit: dBm

Default Value: None


GUI Value Range: -115~-25

Actual Value Range: -115~-25

Unit: dBm

Default Value: None


2D RSCPvalue number of cell proportion

-100dBm 1819 65.27%-103dBm 890 32.89%-95dBm 21 0.72%-10dBm 16 0.59%-97dBm 7 0.24%-90dBm 7 0.23%

-105dBm 1 0.04%-85dBm 1 0.03%

2F RSCPvalue number of cell proportion

-97dBm 1818 65.21%-100dBm 907 33.54%-92dBm 20 0.68%-94dBm 7 0.24%-87dBm 7 0.23%-98dBm 1 0.04%-90dBm 1 0.03%-80dBm 1 0.03%


Hystfor2D -- Hysteresis for event 2D.

Hystfor2F -- Hysteresis for event 2F.

HystforinterRAT -- Inter-RAT Hysteresis



Actual Value Range: 0~14.5, step:0.5

Unit: dB/ dBm

Default Value: None




Unit: dB/ dBm

Default Value: None




Unit: dB

Default Value: None


2D Hyst

value number of cell proportion

2dB 2718 99.45%1dB 30 0.55%

0 14 0.00%

2F Hystvalue number of cell proportion2dB 2762 100.00%

HystforinterRATvalue number of cell proportion

0 2760 99.93%2dB 2 0.07%


TrigTime2D -- Interval time between detection of event 2D and sending of the measurement report.

TrigTime2F -- Interval time between detection of event 2F and sending of the measurement report.


GUI Value Range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280,

D2560, D5000

Actual Value Range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000

Unit: ms

Default Value: None


GUI Value Range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280,

D2560, D5000

Actual Value Range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000

Unit: ms

Default Value: None


• Current netwrok setting(1st Oct): All cell be set to D1280

TRIGTIME 2Dvalue number of cell proportionD320 2716 98.33%D120 37 1.34%D200 7 0.25%D160 2 0.07%

TRIGTIME 2Fvalue number of cell proportion

D1280 2762 100.00%


TIMETOTRIGFORNONVERIFY

Time delay for triggering handovers to GSM cells with non-verified BSIC.

GUI Value Range: 0~64000, 65535(not perform inter-RAT handovers to non-verified GSM cells)

Actual Value Range: 0~64000, 65535

Unit: ms

Default Value: None; Recommended Value: 0

TIMETOTRIGFORVERIFY

Time delay for triggering handovers to GSM cells with verified BSIC.


Actual Value Range: 0~64000

Unit: ms

Default Value: None; Recommended Value: 0 (immediately)





3G to GSM handover steps (By coverage)


Step 1

Event 2D and event 2F are used to enable and disable the compressed mode respectively. When

the cell is located in the center of the frequency coverage or the inter-frequency measurement

quantity uses both Ec/No and RSCP, then the Ec/No value is used as the criterion for events 2D and

2F.

/2HTQ 2d2dUsedUsed

/2HTQ 2fused2fUsed

InterRATCSThd2DEcN0、 InterRATCSThd2FEcNO、 InterRATCSThd2DRSCP、 InterRATCSThd2FRSCP;

HystFor2D、 HystFor2F、 TimeToTrig2D、 TimeToTrig2F• Current netwrok setting(1st Oct):

H2d = 2dB

H2f = 2dB

TimeToTrig2D = 320ms

TimeToTrig2F = 1280ms

2D EC/N0 2F EC/N0

value number of cell proportion value number of

cell proportion

-14 1909 72.42% -12 1909 73.01%-12 823 26.76% -10 823 26.23%-10 30 0.81% -8 30 0.76%

2D RSCP 2F RSCP

value number of cell proportion value number of

cell proportion

-100 1819 65.27% -97 1818 65.21%-103 890 32.89% -100 907 33.54%-95 21 0.72% -92 20 0.68%

-102 16 0.59% -94 7 0.24%-97 7 0.24% -87 7 0.23%-90 7 0.23% -98 1 0.04%

-105 1 0.04% -90 1 0.03%-85 1 0.03% -80 1 0.03%


3G to GSM handover steps (By coverage)


Step 2

• Current netwrok setting(1st Oct): TargetRatCsThd= -95dBm

HystforinterRAT= 0 ; TIMETOTRIGFORVERIFY=0

If the quality of the cell of another RAT in the inter-RAT measurement report fulfils the following criterion:

Mother_RAT + CIO >= Tother_RAT + H/2

Then, the system starts the trigger timer, and makes the handover decision after the timer expires.

If the quality of the cell of another RAT fulfills the following criterion before timeout:

Mother_RAT + CIO < Tother_RAT - H/2

The RNC stops the timer and waits for another inter-RAT measurement report.

Mother_RAT is the measurement result of the GSM RSSI.

Tother_RAT is the inter-RAT handover decision threshold.(TargetRatCsThd)

CIO is the offset for the cell of another inter-RAT.

H is HystforinterRAT, the setting of which can reduce wrong decisions caused by signal jitters.


SUMMARY


For example used the current mainstream configuration, the handover will be executed:

When the Ec/Io of 3G_service_cell < -14 – 2/2 ( Ec/Io< -15dB)or RSCP < -100 – 2/2 ( RSCP < -101dBm

)

2D event was reportCompression Mode Started, start to measurement GSM neighbor cellStart compression timer (60s), If the handover not successful before timeout, stop compression mode

Hold 320ms

zzzzzzzzzzzzzzzzzzzzReport measurement result every 1000ms

If Ec/Io of 3G_service_cell > -12 +2/2(Ec/Io > -11dB) or RSCP > -97 +2/2 (RSCP>-96dBm)

Hold 1280msSTOP compression ModeRESET timer

Mother_RAT>-95dBm +0

Hold 0s

Hand over to GSM

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Documents

Omantel 3G Handover to GSM Parameter Study Report