04/11/2023

IRAT HO Performances’ AnalysisThrough GPEH Logs Measurements

Objectives

This document is aimed to outline the findings and analysis with respect to the Poor IRAT HO performances and the condition perceived by the real subscribers for the early IRAT HO at the improper spots The analysis was taken from the GPEH RNSNK01’s logs in October 2012

IntroductionThe analysis is divided into 3 categories:

1. Fact 01: RAB STATES vs FAILURE RATES• Target: to identify which RAB State contributes to the high failure

rates beside CS Conv 12.2 2. Fact 02: Finding the avg GSM RSSI at IRAT HO

• Target: to set gsmThresh3a properly based on the common RSSI levels

3. FACT 03: Analysis on Pilot Pollution with respect to improper IRAT HO• Target: to identify the pilot polluters and proceed with

recommendation

GPEH analysis: IRAT HO Failures ….. FACT# 1

Conv. CS speech 12.2 Conv. CS speech 12.2 + Interact. PS (0/0)

Conv. CS speech 12.2 + Interact. PS (64/64)

Conv. CS speech 12.2 + Interact. PS (64/HS)

Interact. PS (RACH/FACH)

0

5

10

15

20

25

30

35

4036

23

1

10

3

IRAT HO FAILURE - RAB STATES / RNSNK01

Total

Note:1. Conv CS Speech 12.2 + Int PS 0/0 is the second highest

contributors to the IRAT HO failures followed by Conv CS Speech 12.2 + Int PS 64/HS

2. In order to minimize the failure rates of IRAT HO (CS), the attempt from two RAB States should be reduced

3. Offset as low as -20 ~ -50 is feasible for a trial

GPEH analysis: IRAT HO Failures ….. FACT# 1

Note:1. Proposed values for serviceoffset2DEcNo = -10 &

serviceoffset2DRscp = -20 for both UeRc’s

UeRc ID serviceOffset2dEcno serviceOffset2dRscp UserLabel

UeRc=19 0 0 Conv. CS speech 12.2 + Interact. PS (64/HS)

UeRc=9 1 0 Conv. CS speech 12.2 + Interact. PS (0/0)

GPEH analysis: gsmThresh3a….. FACT# 2

Note:1. Through the table of GPEH IRAT HO Analysis above, Avg GSM RSSI

@ IRAT HO or E3A can be obtained during recording period2. The next step is to filter out the row with poor IRAT HO Command

Success Rates hence the Avg GSM RSSI @IRAT HO are obtained

GPEH analysis: gsmThresh3a….. FACT# 2

Note:1. The range of Avg GSM @IRAT HO in the format of Histogram

charts presented above2. Obviously noticeable that a number of successful IRAT HO

occurred at which the GSM RSSI is within the range of -65 ~ -75, dBm

3. Propose to amend the current gsmThresh3a to any value within the range above, started from -77 dBm going higher

-81 -79 -77 -75 -73 -71 -69 -67 -65 -63 -61 -59 -57 -55 -53 -51 -49 -47 -45 More0

5

10

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25

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35

40

45

50

0 1

19 20

26

45 4446

37

20

11

7 6 6 5

0 02

0 0

Histogram of Avg GSM RSSI at IRAT HO (dBm)

Frequency

Bin

Freq

uenc

y

GPEH analysis: Pilot Polluter ….. FACT# 3

Note:1. Early unnecessary CM leading to IRAT HO or not might also be

attributable to the Ue being served by the polluter cell(s)2. Typically polluter cell(s) is considered those with distance greater than

equal to 2 km from Best Server(s), taking the site-to-site distance into account in the areas

GPEH analysis: Pilot Polluter ….. FACT# 3

Note:1. Through the previous table, the average Polluter’s EcNo are depicted

from the histogram charts above2. The most dominant values are -16 ~ -19, dB3. These range of EcNo values confirm to contribute to the poor call Quality

at the spots of which the Ue’s being served by4. Ue’s being served by this poor quality polluter(s) could experienced 2

possibilities: call dropped or early unnecessary CM leading to IRAT HO or not

-21 -20 -19 -18 -17 -16 -15 -14 -13 More0

2

4

6

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12

14

Histogram - Avg Pilot Poluter's EcNo, dB

Frequency

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Freq

uenc

y

GPEH analysis: Pilot Polluter ….. FACT# 3

1. Best server of BKK0086-1B is being polluted by polluter of BKK2095-1B2. The distance between them obviously indicate the overshooting from BKK2095-1B3. Such phenomena could possibly trigger the unecessary CM leading to early IRAT HO beside the quality degradation at the spot(s) of

which the Ue’s being served by the polluter(s)

GPEH analysis: Pilot Polluter ….. FACT# 3

The complete list of pilot polluters of RNSNK01 is as per attached: RNSNK01_20121005.xls

Summary

1. The IRAT HO performances have been reported poor for either Statistics wise and User’s perception level

2. Through the GPEH analysis, it is found that the current settings are encouraged to be revised as per FACT 01 above for serviceOffset2dEcNo or RSCP for RAB STATE other than CS Conv 12.2

3. This is intended to reduce the IRAT Failures during the attempt from each RAB Types above: Conv CS Speech 12.2 + Int PS 0/0 and Conv CS Speech 12.2 + Int PS 64/HS

4. FACT 02 concludes that the common GSM RSSI falls within the range -65 ~ -75, dBm5. FACT 03 also concludes that the pillot pollution has significant contribution to the IRAT performances

in addition to the poor call quality6. Each of analysis types above have been followed by the solution and recommendation which should

be implemented on one particular RNC as trial