S07 3G RPLS2_v2-0 GSM Measurement

8/13/2019 S07 3G RPLS2_v2-0 GSM Measurement

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1 NOKIA topic: GSM Measurements for Inter-RAT Cell Reselection & Handover/ July 2003 /Markus Wimmer

GSM Measurementsfor Inter-RAT

Cell Reselection Handover


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Cell Reselection and Handover

Cell Reselection HandoverDone by MS in the (circuit switched) idle mode, and packet idle and packet transfer modeGSM cell re-selection to WCDMA may differ between non-GPRS capable mobiles, GPRS capable mobiles, and GPRS capable mobile with Packet BCCHCell reselection to weaker WCDMA cells is possible

Handover from GSM is supported if the load of theserving GSM cell is above certain threshold and themeasured quality (CPICH Ec/No) from adjacentWCDMA cell is above a minimum value.Different load threshold for speech calls and Non-Transparent (CS) Data can be set.


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Load Reason Algorithm in RAN 1.5Speech calls can be served adequately both in GSM and UMTS. Consequently, only in a high load situations, multiple RAT phones are

handed over from GSM to UMTS. The number of occupied traffic channels on the available transmission resources triggers the handovdecision in the BSC.

Circuit switched data calls may not surpass a capacity threshold before the BSC imitates the HO procedure.GPRS MS can be directly pushed to 3GPP cell reselection.


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Load Reason Algorithm in RAN 1.5

100%

80%

0%

Service based handoversfor non-transparentdata to provide maximumuser bit rates

Load reasonhandoversfor speech

Load of GSM cell (Occupation of TCHs in TRXes)

Data to WCDMAregardless of GSM load

Speech to WCDMAonly with high GSM load

Higher bit ratesfor data users

More capacity for speech

Packet BCCH parameters can be usedto push GPRS mobiles to WCDMA


5/125 NOKIA topic: GSM Measurements for Inter-RAT Cell Reselection & Handover/ July 2003 /Markus Wimmer

Cell Reselection Algorithm from GSM to FDD-WCDMA (cs)

WCDMA measurements, when:

RLA_C Qsearch_I (Non GPRS)

If, for suitable UMTS cell& for a period of 5 s:

CPICH RSCP > RLA_C + FDD_Qoffset

CPICH Ec/No FDD_Qmin

no priorities

between WCDMAneighbours

Measurement Updates: RLC_C value of the serving cell at least 6 strongest non serving GSM cells

at least every 5 s

check

and WCDMA cell

reselection



Example: cs Cell-Reselection to a Stronger WCDMA Cell

Qsearch_I (e.g. 98 dBm)

5 seconds

Cellreselection

time

FDD_Qoffset(e.g. 8 dB)

Start WCDMA

measurements

ServingGSM cell

Non servingneighbourGSM cell

Suitable neighbour

WCDMA cell

CPICH Ec/No

FDD_Qmin



Example: ps Cell-Reselection to a Weaker WCDMA Cell

time

Qsearch_P (e.g. 70 dBm)

Start WCDMAmeasurements

FDD_GPRS_Qoffset(e.g. -8 dB)

CellreselectionCPICH Ec/No

FDD_Qmin

5 seconds

ServingGSM cell

Non servingneighbour

GSM cell

Suitable neighbourWCDMA cell



Cell Reselection Parameters

ParameterParameter forNON GPRS

Qsearch_X Qsearch_I

FDD_Qoffset FDD_Qoffset

RLA_X RLA_C

Parameter forGPRS

Parameter forPBCCH GPRS

Qsearch_P Qsearch_P

FDD_Qoffset FDD_GPRS_Qoffset

RLA_P RLA_P

0

-98

8

-78

1 2

-94 -90

9 10

-74 -70

3

-86

11

-66

4

-82

12

-62

5

-78

13

-58

6 7

-74 Always

14 15

-54 Never

R_Below

dBm

R_Upper

dBm

0

Always

8

0

1 2

-28 -24

9 10

4 8

3

-20

11

12

4

-16

12

16

5

-12

13

20

6 7

-8 -4

14 15

24 28

Range

dB

Range

dB

0

-20

1 2

-19 -18

3

-17

4

-16

5

-15

6 7

-14 -13

Range

dB

Parameter

Name forSys Info (SI)

Qsearch_I

2quater

Qsearch_P Qsearch_P

2quater 3quater

FDD_QMin

2ter

FDD_(GPRS)Qoffset

2quater

FDD_REP_QUANT

2ter

3G_search_PRIO

2(3)quarter(PBCCH)

FDD_Qmin

Qsearch_I & Qsearch_P

FDD_Qoffset & FDD_GPRS_Offset


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Handover Process incl. RAN 1.5

Handover Triggering Thresholds set in BSC

Inter-RAT measurements when:The RXLEV of the serving cell is above or

below the given thresholdQsearch_C

Handover Decision is done in case of Load of the serving cell >Load_Threshold and CPICH Ec/No> min Ec/No Threshold

MS reports best UTRAN cell basedon measurement results

Handover command is send to MSC

Latest after 5 s(one WCDMA band)

However in S10.5 MS is measuring the UTRAN cellscontinuously if they are defined as a neighbour,measurements are done during idle periods


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Example: Handover to a Weaker WCDMA Cell

Qsearch_C

Serving GSM cell

Non servingneighbourGSM cell

Suitable neighbourWCDMA cell

FDD_Qoffset(< 0)

5 seconds

Cellreselection

CPICH Ec/NoFDD_Qmin


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GSM ISHO in RAN1.5: Example

Load Threshold for Speech Calls inter-RAT Handover LOAD_THRESHOLD_FOR_SC_IS_HO= 80%

Min Ec/No threshold for a handover to the UTRAN adjacent cell MIN_ECNO_THRSHOLD = -15 dB

Qsearch_c = 15 (if Qsearch_c = 15, the mobile is not allowed to measure UTRAN adjacent cells and

therefore the BSS does not send the Measurement Information message to the mobile at all)1 Load of the serving cell = 45% and the measured Ec/No = - 20 dB

--> Handover to the UTRAN not possible due to low load and low Ec/No

2 Load of the serving cell = 45% and the measured Ec/No = - 10 dB--> Handover to the UTRAN not possible due to low load

3 Load of the serving cell = 95% and the measured Ec/No = -10 dB--> Handover to the UTRAN possible

Handover example (speech/Transparent data)-


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GSM ISHO in RAN1.5: Example

Handover example (Non Transparent data)-

Load Threshold for Non-Transparent Data inter-RAT Handover

LOAD_THRESHOLD_FOR_NON_TPC_IS_HO =0% (default)

Min Ec/No threshold for a handover to the UTRAN adjacent cell

MIN_ECNO_THRSHOLD= -15 dB

Qsearch_c = 15 (if Qsearch_c = 15, the mobile is not allowed to measure UTRAN adjacent cells andtherefore the BSS does not send the Measurement Information message to the mobile at all)

1 Load of the serving cell = 0% and the measured Ec/No = - 20 dB--> Handover to the UTRAN not possible due to low Ec/No

2 Load of the serving cell =0% and the measured Ec/No = - 10 dB--> Handover to the UTRAN possible

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S07 3G RPLS2_v2-0 GSM Measurement