RF Optimization Tips: 3G UMTS/WCDMA Drop Call Rate Improvement(DCR CS/PS) in 3G Network Huawei

Today I would like to share 3G UMTS/WCDMA Drop Call Rate Improvement in 3G Network Huawei. Some parameter for drop call rate improvement especially for CS service in 3G network need to adjust to improve DCR CS. Drop call in 3G network is one of KPI that need to be optimized especially when customer ask for KPI improvement on the Network. Parameter below can be implemented to improve drop call rate in 3G Network Huawei especially for CS service(DCR CS).

1. Enable CS_DISCONNECT_OPT_SWITCH
2. Enable RRC_SCRI_NORM_REL_SWITCH

Description of each parameter:
- CS_DISCONNECT_OPT_SWITCH
Whether the RNC performs optimized processing if the UE does not respond within 3 seconds after receiving a DIRECT TRANSFER message from the CN during a CS call release. The value of the IE Message Type in the DIRECT TRANSFER message is Disconnect.
1: This switch is turned on. The RNC creates a DIRECT TRANSFER message and sends it to the CN. The value of the IE Message Type in the DIRECT TRANSFER message is Release.
0: This switch is turned off. The RNC does not create the DIRECT TRANSFER message

Script to enable this Switch:

SET URRCTRLSWITCH:IMPROVEMENTSWITCH=CS_DISCONNECT_OPT_SWITCH-1;

- RRC_SCRI_NORM_REL_SWITCH (Switch for Performing the Optimized RRC Connection Release Procedure on Receipt of a SIGNALLING CONNECTION RELEASE INDICATION Message)
1: This switch is turned on. The RNC initiated the normal release process after receive SIGNALLING CONNECTION RELEASE INDICATION message from UE.
0: This switch is turned off. The RNC does not handle SIGNALLING CONNECTION RELEASE INDICATION message during the process.

Script to enable this Switch:

SET URRCTRLSWITCH:PROCESSSWITCH2=RRC_SCRI_NORM_REL_SWITCH-1;

The other way to improve 3G DCR CS/PS in 3G UMTS/WCDMA Huawei Network:

1. SHO Optimization (Recommended for Outer Cells)

- MOD UCELLINTRAFREQHO:RNCID=xxx,CELLID=xxx,SHOQUALMIN=-24;

- INTRARELTHDFOR1ACSNVP & INTRARELTHDFOR1BCSNVP = existing + 2

2. RL Power Optimization (Recommended for Cells with high Uu No Reply, Value adjust based on cells with high VS.RAB.FailEstabCS.UuNoReply)

- MOD UCELLRLPWR: CELLID=XXXXX, CNDOMAINID=CS_DOMAIN, MAXBITRATE=12200, RLMAXDLPWR=20, RLMINDLPWR=-140;

3.Radio Link Optimization (Recommended for RNC Level)

- SET UCORRMALGOSWITCH:MAPSWITCH=MAP_CSPS_RL_RESET_0K_LIMIT_SWITCH-1;

- SET UCORRMPARA:PERFENHANCESWITCH3=PERFENH_RLRESETUP_GUARANTEE_SWITCH-1,PERFENHANCESWITCH5=PERFENH_FACH_TVM_MC_TIME_OPT_SWITCH-1;

- SET URRCTRLSWITCH:PROCESSSWITCH4=RRC_CELLFACH_DL_TRB_RESET_TO_F2D_SWITCH-1,OPTIMIZATIONSWITCH6=ASU_RSP_FAIL_REL_UE-1&CS_TRIG_PS_F2D_SWITCH-1;

Graph below show the result of above parameter changes to improve Drop call rate(DCR CS/PS):

The result show significant improvement for Drop call rate in 3G Huawei network both DCR CS and DCR PS. For Other vendor(Nokia/Ericsson) you can find similar parameters or read parameter mapping between vendor.

You might also Need to know:

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