Change Parameter Max retrans

Krish
Reducing Max no. of Retransmission will reduce SDCCH Holding time for sure.If your site is having a very high SDCCH Blocking ,reducing it will definitely improve your SDCCH Blocking.
Rach Success ratio=immediate asssignment commands/RACH requests.

Poor RACH suceess may be due to poor radio environment,like CO-BCCH-BSIC in nearby sites,Phantom RACH(especially in very low traffic sites),BTS sensitivity,No SDCCH.you can also increase the RACH min. access level(def. -105) to improve RSR.

Hi Bijoy,

As per my understanding:

MaxRetrans relates to RACH retry for different Access Cause.

As our OMCR server only pegs/trigger (increment)the counters on the basis of Abis messages or Ater messages. So, in real we cant calculate our RACH Success Ratio. That is one of the reason “RACH Success Rate” is calculated using the response from the BTS with message “Channel Act Ack” for “Channel Act” send by the BSC. “Immediate Assignment Reject” directly relates to the Hadware fault as this transparent message is send after recieving the “Channel Required” from BTS and when in the BSC allocation table required resource is not present.

Hi,
what is importance of enabling Immediate assignment reject in BSC, what’s its role?
Thanks,

Hi bijoy,

once again abt rach max retran .

if i have its value 4 andi have high sd blocking due to high traffic then in this case by decreasing it 2 ,as per said by u it will decrease sd blocking

but can u tell me if on my first rach bts will not allocate sdcch then ms will try second time so here actually sd is not assign form bts side so how it will reduce sd blocking?

and whatever i said above is it beneficial to inprove rach success?

Hi pix,

thanks for reply. but i want to know if ms sends 2 time rach request and no response from bts side then in picture where sd comes because bts is not giving sd and because of that ms sends 3 ,4 time rach request.so it how to increase sd blocking……

and second if i have poor rach success ratio and my bcch-bsic and hardware is ok then by increasing rach max retrans from 2 to 7 and tx integer from 10 to 50 will help to improve rach success ratio.. plz explain..

Hi Thanks pix,

and second if i have poor rach success ratio and my bcch-bsic and hardware is ok then by increasing rach max retrans from 2 to 7 and tx integer from 10 to 50 will help to improve rach success ratio.. plz explain..

RACH success will be improved by proper TX INTEGER tuning (50) and activation of the IMMEDIATE ASSIGNMENT REJECT message.

The number of retrans is, IMO, useless, but you can give it a shot anyway !

Cheers,
Pix

For S and TX INT yes, they work in couple.
Look at 3GPP to find the exact formula… but otherwise you can simply use the default value of TX INT = 50 with S = …? (isn’t it written somewhere in your docs ? i can check tomorrow for the S value, i forgot 🙂 )

For IMM Asg Reject : yes, it will reduce sd congestio and racch failure etc… Why didn’t you enable it already ? we gave you all details about this feature in past posts…

Cheers,
pix