PS IRAT & CS DCR Improvement - U900

[khurrambilal01]

Hi All,

We are having a U900 + U2100 NW with Huawei RAN 14.0, PS IRAT SR is very low for U900 sites, normally its like 90-91%.

1) How to improve PS IRAT, because we have already optimized HSPA/R99 2D/2F and triggering parameters.
2) How to improve CS DCR on U900 layer because it's coverage is more than U2100 and even GSM 900 because of UL noise difference b/w GSM & WCDMA? currently CS DCR is around 0.9%?

We have tried some parameters like MaxRLPower for CS AMR and Maximum DCH rate for multiRAB AMR call, any other parameters? Suggestions?

[khurrambilal01]

Hi Experts,

Any suggestions? Reputation will be added for helpful support.

[amadeo]

hi bilal,
I am not Huawei engineer but i can help you as common sense.
Improve PS IRAT:
1. Make the triggering event harder. (lower the threshold of RSCP or EcIo so that it will maintain to keep the call in the band). This will prevent pingpong or unnecessary IRAT.
2. Make the target cell qualification stricker (increase the minimum RSCP as target into -95 dBm or anything else you have in huawei).

Improve CS DCR:
1. Make sure no overshooting and have a balance uplink & downlink. Check if your UL_Out_of_Synch couonter is high but your SHO failure is low. This indicate you have limitation on uplink. This can only be solved by reducing your coverage either by downtilt or reduce CPICH.
2. CHeck your PRACH plot, make sure the distance until 98% of your traffic area has all neighbors defined.
3. Check your SHO OH. If they are low (< 20%), that means you have coverage gap. Try to uptilt your neighboring cell and also check the serving cell. If they are high (> 40%) and your prach plot is far (>10 km), downtilt your server.
4. Increase your T313

Hope this will help.

cheers,

amadeo

[khurrambilal01]

Hi amadeo;
Thanks for the reply.

I have already changed CS 2D/2F to -14/-12 with hysteresis zero, CS RSCP 2D/2F -97/-95; PS 2D/2F is -16/-14 and RSCP is -115/-110.

For interfreq Target EcNo threshold is set to -10 and RSCP is -95 while for GSM target RSSI is -90...

NinsynInd is changed to 3 from 5 and outsyncind is default value 50.

Still CS DCR is 0.8 and CS IRAT is 97 while target is 97.5, PS IRAT is 91% while target is 95%.

[Syed Fahad]

Khurram Sb,

Do we know the IRAT Failures are in Preparation or Execution Phase.
DL / UL TBF Congestion on 2G can impact the Preparation Failures .
Some times very low Values for PDCH Rate at 2G End can give rise to TBF Congestion impacting PS IRAT Prep Failures.
While External Inference at 2G End also impacts IRAT Execution Failures.
In NSN we have tried Multiple BSIC Identification Feature in which BSIC Identification of more than One GSM Neighbor is performed that lead to slight improvement in CS IRAT Success Rate.
For CS DCR, If T314 > 8s / 10s than 0.8 is way too much provided no External Interference issues.

[dtvt2]

Hi
- Enable BSIC verify
- Planning frequency 2G

[khurrambilal01]

Hi
- Enable BSIC verify
- Planning frequency 2G

BSIC verfiy switch is already enabled and we have recently done AFP for 2G...

[khurrambilal01]

Khurram Sb,

Do we know the IRAT Failures are in Preparation or Execution Phase.
DL / UL TBF Congestion on 2G can impact the Preparation Failures .
Some times very low Values for PDCH Rate at 2G End can give rise to TBF Congestion impacting PS IRAT Prep Failures.
While External Inference at 2G End also impacts IRAT Execution Failures.
In NSN we have tried Multiple BSIC Identification Feature in which BSIC Identification of more than One GSM Neighbor is performed that lead to slight improvement in CS IRAT Success Rate.
For CS DCR, If T314 > 8s / 10s than 0.8 is way too much provided no External Interference issues.

Hi Syed Fahad ;

IRAT failures are in Execution phase with reason physical channel failure.
BSIC verfiry switch is already enabled, External interference on 2G is only present for two airport sites, rest all are clear, Although one thing that i think can be the cause is NBR list truncation because we have defined many NBRs for IRAT as well as IF (U2100 F1/F2 And U900 F3).

T313 value is 3sec, but this timer is RNC level and we have good performance for U2100 with same timers in same RNC but U900 has higher DCR.

[Syed Fahad]

Being X Huawei, i understand that huawei Management wont take it as an excuse, but as matter of fact after deployment of third carrier on 900Mhz, your UMTS 900Mhz Traffic and coverage might be increased and improved. The Routine coverage related VIP Customer complaints on Naster would be reduced. But i am of the view that comparing U2100 KPIs with U900Mhz KPI is not justified.. U900Mhz being on lower frequency will be having high penetration power and with respect to U2100 and vice vera. Noise floor on U900Mhz will be high as result of that with compare to U2100, as it will be taking higher share of traffic.
Any ways coming to PS IRAT Issue, can we make sure that is there any feature in Huawei with Force Decode BSIC Option for NRT. As per my understanding BSIC is not decoded for NRT IRAT HO/ Cell Changes, its only for CS IRAT.

[khurrambilal01]

Being X Huawei, i understand that huawei Management wont take it as an excuse, but as matter of fact after deployment of third carrier on 900Mhz, your UMTS 900Mhz Traffic and coverage might be increased and improved. The Routine coverage related VIP Customer complaints on Naster would be reduced. But i am of the view that comparing U2100 KPIs with U900Mhz KPI is not justified.. U900Mhz being on lower frequency will be having high penetration power and with respect to U2100 and vice vera. Noise floor on U900Mhz will be high as result of that with compare to U2100, as it will be taking higher share of traffic.
Any ways coming to PS IRAT Issue, can we make sure that is there any feature in Huawei with Force Decode BSIC Option for NRT. As per my understanding BSIC is not decoded for NRT IRAT HO/ Cell Changes, its only for CS IRAT.

Yes U900 has improved coverage, Traffic and penetration. RTWP is relatively high as compared to U2100 layer, Alot of CS traffic has been captured by U900 + HSDPA traffic, Some cells are bursting. 20-30% revenue has increased.

I can't find any feature which can force BSIC verification but there is a parameter which can delay/disable handover when BSIC is not verified.I would try this parameter but risk is increase in call drops...