PSR degrading ..

[rf _engg]

Hi all,I am facing a problem in my network,when i change RLT value from 20 to 28 ,my PSR going down 3% ,please suggest what parameter should i change to improve PSR.

[linhhy]

Hi all,I am facing a problem in my network,when i change RLT value from 20 to 28 ,my PSR going down 3% ,please suggest what parameter should i change to improve PSR.

Hi,

What is RLT ? (radio link timeout?)

[rf _engg]

ya its Radio Link Timeout....

[taki]

Hi

You mean by PSR (Paging Success Rate) , so to increase the PSR you have to check if you have High SD blocking or Drop, check also if you have coverage gap
Check also Paging deletion rate

BR

[louvre]

Hi,

please check the following.

1. SD Blocking/ Attempts - SD TS increase might be required, but it might have also been caused due to hardware fault!!!

2. LU - is Location updates within normal parameter.

3. Paging MS deletion/flush

if its a case you can also play about with Access grant and Multi frame Block value.

4. LAC splitting if LAC is overloaded

5. Play with the Global Paging setting to further reduce the paging volume.

6. Type of paging used( IMSI, TMSI) and order in which they are done.

7. Hot spot in the LAC..

8. Any major change that might have been done in line with BCCH, layers etc.

9. 3G/4G activation etc cell reselection parameter need to be checked as this will increase paging load if they are having different LAC causing drop in PSR.

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[mike_symbol]

Are there alarms in the cell or cells affected by LOw PSR?this affect PSR performance.
Is your PSR set to more than 1?
IS your TA set to 63?
Is your AG_BLKS_RES set to 2 or 1, depending if compounding or non compounding (for HUAWEI).
If this are usefull suggestion, please add rep and thanks.

[rf _engg]

thanks to all for reply....

>as i m changing RLT parameter in ALL sites of BSC so alarm hardware not countable
>we using TMSI for first paging type

>as first point BSC utilization only 10% so there is not possibilities of Congestion
>LAC spllitting a option to improve PSR in case Traffic loaded

my Q. remain unanswered why PSR degrading with change in RLT value...... as increase in RLT improving SD and TCH Drop so why degradation in PSR ???
1.what parameter should i need to look at BSC and MSC end
2. as we are improving SD hold time then why PSR degrading??
3. please suggest if any timer need to check.....
4.Paging repeating ....

[louvre]

1. Increasing the RLT increases the time for how long the call will be hold before its dropped!! so it improves drop rate. but on the other side you are also increasing call drag time. So you need to figure out where is this call drag having more effect. Can be found out by comparing the drop rate pre and post change of RLT.

2. Also Check if you have call re-establishment as it will definitely cause paging problem if your network has many coverage holes and many drops were happening due to RLT expiry before the change of RLT or poor radio coverage.

[zhanglw268]

When you cange the RLT from 20 to 28, you added extra 3.8 seconds to let the mobile hold the channel (TCH or SDCCH depending on the MS used), the total time will be minimum 13.4 seconds long, the other end user may have lost the patient and disconnected the call long time ago and MSC may have cleared the call (depending on T305 and T308 etc. timers setting at the MSC), and redial this user, but this mobile is still in the dedicated(SDCCH or TCH) mode so the mobile can't receive the paging message, also other users may call this mobile at the same time and MSC may think that this mobile shall be in idle mode, there is extra paging messages without reply, this is the main reason that your PSR drops.

Usually setting RLT to 20 is longer enough, if your network drop call rate is high, you shall find out the reason and resolve them rather than simply change the RLT to make the statistics looking better, the end user experience becomes worse.

You shall revert the RLT setting to 20, try to work out other changes.

[maverrickforever]

Hi,

What is RLT ? (radio link timeout?)

Hi linhhy, by radio link timeout we mean the parameter which determines how long the MS will be able to hold the radio resource before the MSC triggers a radio resource release. By the customer prospective it is time when after degradation of the quality of signal the customer waits till the time either he is disconnected from network, of if the parameter is set too high he disconnects. The value of RLT is set in terms of value of SACCH frame timeline. Like 20 or 28 ( SACCH frames) i.e. the time line = Timeline of 1 SACCH frame x value of parameter ( eg 20 or 28).

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