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Hi All,
Iam having low CSSR due to message failure at assignment level,what could be causing that.On other instances i have High immediate assighnment withiot MS_Seizure.I would appreciate if i can get an explaination on the same.
Possible solutions to counter low CSSR will be appreciated.
Rgds
NachiLow CSSR due to poor assignment success…
First, which assignment ? The SDCCH or the TCH ?
Possible low CSSR (depending on your CSSR formula !!)
SDCCH congestion
poor radio conditions on BCCHpoor radio conditions on SDCCH
TCH congestion
poor radio conditions on TCH (unable to access the ts TCH)and hardware failure : abis, combiner, tre, crossed tre, crossed sectors, etc…
regarding IMMEDIATE ASSIGNMENT, the possible failure cause is mostly SDCCH congestion. Check the SDCCH traffic and resources usage, you might notice you’re exceeding the offered traffic.
Regards,
Hi Pix,
In my pointof view Immediate Assignment will never be due to SDCCH Congestion. SDCCH congestion may cause SDCCH Allocation failure. Poor SDCCH assignment success rate can be due to CO BCCH CO BSIC conflicts, poor quality, VSWR and other h/w failure.
Hi Pix,
The CSSR in my network is ~90 in most of the cells even when there is no SDCCH assignment failure, no TCH assignment failure, no allocation failures, no blocking on SD adn TCH. Can u suggest me at which end(MSC, BSC, BTS) i will look to improve my CSSR.
Regards
hi,
1.in Tems Investigation report, whats is the definition of call attempt, call setup, call established, and call ended?
2.i have seen that sometimes number of call established in not equal to no. of calls ended, why?Kindly help me
Rajiv,
I think your 90% CSSRs are due to the different between the sdcch attemps and sdcch assignment. If you type the formula of the CSSR used in your network, things will be more clear.need help on how to solve Sdcch Assign Failures… thanks for all the help.
Hi guys, how can one effectively push traffic to 1800Mhz band if the 900Mhz is congested in HCS systems.
Euge2007,
i don’t know the E/// system, yet I believe they are using a kind of “capture” handover from 900 to 1800. Check their handover types.
Hi,
If there is congestion in A channels and call assignment failure occures due to that – then will it be considered as call drop in radio ?
fahim,
no the call hasn’t been established yet, so this is a call setup failure, and more exactly, it is a TCH assignment failure.
regards,
pixHi Pix,
U have made my conception clearer – thnx. Can you tell me any other KPI in A-channels which might affect cal drop or CSSR in radio ?
every kind of failures on the a interface would lead to a call drop or a call setup failure, isn’t it ?
but it’s a bit tedious to list all of them.. i’m not going to do it 🙂what is sd drope & cssr ?
sdcch drop : drop during the sdcch phase (could be for LU, call setup, SMS, …)
CSSR : call setup success rate : failure or drop during any phase between a channel request and the succesful establishment of a TCH. It includes the SDCCH drops, TCH assignment failures, sometimes also, the SDCCH assignment failures . It is vendor dependent.
regards,
pix
