Improving call setup time for 3G

[eric4good]

Dear Members,

I am currently investigation call setup time on 3G, its has been noticed its taking longer time to setup a call.
Any ideas how to improve call setup time from both RAN and core sides.
As well any ideas as to what are the main causes behind a long setup time for 3G.

Thanks in advance for sharing your experiences, (BTW vendors are Huawei and ZTE).

BR,

Fuad

[khurrambilal01]

Normaly if cell load is high then it takes further time for Re-direction/DRD that can cause an increase in call set up time,
what is your average call setup time for AMR/HSDPA?

You can use the switch to enable call setup on FACH as well which will reduce the call setup time.

[Muhammad Imran Rafique]

hi Khurram,
Can you share the details how we can activate call setup on FACH? What is the possible gain from normal procedure.

BR//
Imran

[electron]

Hi Imran,


I guess Khurrambilal is talking about direct up switch from FACH to HS. There is such optional feature in E/// as well.



Cheers
hi Khurram,
Can you share the details how we can activate call setup on FACH? What is the possible gain from normal procedure.

BR//
Imran

[ninjafine]

Hi Eric4good, if you are talking about CS, please check if the problem is with MT or MO
calls. For PS you may use SRB over HSDPA.

[yafawi79]

High fuad:
Allow me please to share with you one senario we faced it in our network. We noticed that call setup in MO taking longer time than usual with switch off message when we do MT. After doing several MO and MT tests in random geographical areas. It was observed that UE most of the time is taking long time while re selecting from one cell to another.which make the UE during this unreachable and taking longer time in RRC process.cause the UE has first to measure the signal level of each neighbour cell; rank it;if one cell found to be better than the serving cell; THE UE wait for Treselect to expire before camping on the neighbour cell and read the broadcasted SIBS. (or requeat for LAC update if the cell was on different LAC area). TO speed up this process and to avoid call delay . Treselect was tuned from 5s to 1s. And the problem was solved.
Hope this will be helpful
Thanks and best regards.

[dtvt2]

hi friend
- i think you should check: transmission in your system, check paging group, Increase PSR & RACH SR ( EX increase PRACH C/I)..

[eric4good]

Thanks for sharing, a valid point for speeding reselection, what is the intrasearch and qQualmin values you are you currently using.
BR

[eric4good]

From statistics its as follows
CS
Max RRC setup time is 4s
Max CS RAB setup time is 6s
PS
Max RRC setup time is 4s
Max PS RAB setup time is 8s

I am trying as well to test ping times or RTT (round trip time), the max ping time is below 20ms (nodeB to RNC), but pinging youtube or facebook is returning values above 200ms which I think is a bit high isnt it for 3G? what is the acceptable ping times for 3G.

[ninjafine]

From statistics its as follows
CS
Max RRC setup time is 4s
Max CS RAB setup time is 6s
PS
Max RRC setup time is 4s
Max PS RAB setup time is 8s

I am trying as well to test ping times or RTT (round trip time), the max ping time is below 20ms (nodeB to RNC), but pinging youtube or facebook is returning values above 200ms which I think is a bit high isnt it for 3G? what is the acceptable ping times for 3G.

Hi!
Ping time depends on many things but if we are talking about HS/EUL RAB it's mostly 50-100 ms.

[walnem]

I was able to get an improvement of call setup time from 3s to 1s in PS and CS calls.
The trick is that all the setup establishment phase is done on SRB. The default on most vendors is to set the rate of SRB to 3.4kbps. By setting it to 13.6kbps u will get the messages sent 3 times faster. Performance stayed the same.
I would share the report i wrote but i'm still a junior member so if u can help me with reputation id share the report.
Hope this was helpful (and please if u can help me with reputation that would be great)

[eric4good]

Thanks Walnem, can you share the report by sending to fma_76@yahoo.com
BR


I was able to get an improvement of call setup time from 3s to 1s in PS and CS calls.
The trick is that all the setup establishment phase is done on SRB. The default on most vendors is to set the rate of SRB to 3.4kbps. By setting it to 13.6kbps u will get the messages sent 3 times faster. Performance stayed the same.
I would share the report i wrote but i'm still a junior member so if u can help me with reputation id share the report.
Hope this was helpful (and please if u can help me with reputation that would be great)

[yafawi79]

High fuad:
Glad to hear from you. as per your inquiry Qqualmin is set to -18 and SSearchintrafreq to 5. That is; Cell reselection is triggerd when:
SsignalEcNo < -18 + (2×5)
S EcNo < -8
Thanks and best regards

[dtvt2]

Thanks for sharing, a valid point for speeding reselection, what is the intrasearch and qQualmin values you are you currently using.
BR


Hi friend
In my network. Intrasearch = -6 and Intersearch = -10. To increase speeding reselection you can change Tselection

[incoincov]

From statistics its as follows
CS
Max RRC setup time is 4s
Max CS RAB setup time is 6s
PS
Max RRC setup time is 4s
Max PS RAB setup time is 8s

I am trying as well to test ping times or RTT (round trip time), the max ping time is below 20ms (nodeB to RNC), but pinging youtube or facebook is returning values above 200ms which I think is a bit high isnt it for 3G? what is the acceptable ping times for 3G.

Hi,

How exactly did you measure/get these values? Cheers

[tsiz]

Hi, Maybe you should check what your rrcconnectionsetup timer is set to? If it is set to 9 seconds or more, you have quite a high call setup time. Also, if you have block redirection "on" then it is going to scan for other frequencies after rrc reject which would still increase the call setup time.

[eric4good]

From ZTE performance counters, they have counters to report setup times for RRC and RAB.


Hi,

How exactly did you measure/get these values? Cheers