Paging success Ration (PSR) reach 70% :(

[inexia]

Hi Expert

I found another problem at my network right now. We just perform BSC migration from 1 MSC to another New MSC. Performance report mention that PSR reach 70%, it's so big under our SLA

I am working at Core Part, and this issue suspected from BSS part (we don't have previous PSR value before migration). Is It posibble Paging failure caused by wrong configuration at Core side? Could you give me some example if it is possible?

Thanks in advance
Regards,
Taufan

[dk2000]

Hi,

Could you say more detail about which MSC vendor, BSC vendor?

[uel888]

Hi Expert

I found another problem at my network right now. We just perform BSC migration from 1 MSC to another New MSC. Performance report mention that PSR reach 70%, it's so big under our SLA

I am working at Core Part, and this issue suspected from BSS part (we don't have previous PSR value before migration). Is It posibble Paging failure caused by wrong configuration at Core side? Could you give me some example if it is possible?

Thanks in advance
Regards,
Taufan

Try to check all the parameters if still consistent with the previous MSC prior to migration.

[inexia]

Hi

Hi,

Could you say more detail about which MSC vendor, BSC vendor?

MSC/MGW use Huawei, and BSC use siemens

Try to check all the parameters if still consistent with the previous MSC prior to migration.

I actually, copy all LAC-CI from previous MSC. I create more LAC-CI at MSC than LAC_CI created at BSC side. It should be not impact with PSR is it..??


Thanks for your reply
Regards,
Taufan

[boythanhnam]

Hi Expert

I found another problem at my network right now. We just perform BSC migration from 1 MSC to another New MSC. Performance report mention that PSR reach 70%, it's so big under our SLA

I am working at Core Part, and this issue suspected from BSS part (we don't have previous PSR value before migration). Is It posibble Paging failure caused by wrong configuration at Core side? Could you give me some example if it is possible?

Thanks in advance
Regards,
Taufan

hi,
I have a document E******* about all parameters and recomments how to improve PSR in network. You can read and reference.
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Reputation and thanks are welcome!

[roots]

Hi Expert

I found another problem at my network right now. We just perform BSC migration from 1 MSC to another New MSC. Performance report mention that PSR reach 70%, it's so big under our SLA

I am working at Core Part, and this issue suspected from BSS part (we don't have previous PSR value before migration). Is It posibble Paging failure caused by wrong configuration at Core side? Could you give me some example if it is possible?

Thanks in advance
Regards,
Taufan

Check LAC/LAC/GLOBAL before and after, check the timer T3113, check also whether IMSI or TMSI is used to identfy the MS

[zhanglw268]

You are luck that you only got Dropped PSR, not the whole system down.

First of all, lock or delete the extra LACs and CIs in the new MSC, the extra LACs and CIs may add paging load to the A interface, then BSC(s), the BSC(s) is/are normally configured to paging whole BSC if the LAC/CI is not recongnised, this will add extra paging load to the whole BSC, This may cause paging overload, paging messages will be discarded at BSC/BTS so PSR at MSC will drop.

Secondly, please check that the CIs at the BSCs are not locked at the MSC database, so the paging messages can be sent to the BSCs.

Thirdly, you need to make sure that you don't have same LAC in different MSCs/VLRs, otherwise, it may cause confusion with HLR and the location update may fail and cause mobiles continued location update and used the SDCCH up, mobiles can't use SDCCH to do paging response on time.

Fourthly, please double check these LACs and CIs so they are fully matched between MSC and BSCs if the re-homing is finished.

Fifthly, check the period location update timer T3212 settings at the BSC cells and the BTDM setting at the MSC, make sure that they are having decent value and relation so Mobiles can do normal location update and MSC/VLR and HLR have right information.

Sixthly, make sure that you have the MSC set to paging by LAC, not LAC+CI or other methods, this setting's benefit is that it will reduces the missing/extra CIs in the paging messages at the A interface. For example, if you use paging by LAC+CIs, the missing CIs which is not in the A interface paging message will not be paged at the BSC.

Seventhly, please double check the A interface SS7 timers and CICs settings, make sure that these work in a normal way, so the paging from MSC and paging responses to MSC can go through normally.

Good luck for the troubleshooting.

Zhanglw268

Hi



MSC/MGW use Huawei, and BSC use siemens




I actually, copy all LAC-CI from previous MSC. I create more LAC-CI at MSC than LAC_CI created at BSC side. It should be not impact with PSR is it..??


Thanks for your reply
Regards,
Taufan

[kevin_h811]

I agree with Zhang..pls remember that T3212,MSC is ahead of 1 hour compared to BSC...if possible check your paging times, we were ask by HUAWEi to set it from 1 to 6..AG_BLOCK_RES were also re-defined, and other settings related to PSR Success Rate...just ask your HUAWEI Counterpart..

[leelio]

I just need more clarification...
1. is any other BSC use the same LAC?
2. if (1) is no, before migration did any other BSC shared the same LAC?
3. as zhanglw268 commented, one LAC shouldnt be used by different MSC/MGW. Is this followed?

In addition, you should also check on PSR stats before & after migration for easy comparison.