Following is the Signaling flow analysis
1.MS sends a CHANNEL REQUEST (OK)
2.BTS sends a CHANNEL REQUEST message to BSC (OK)
3.Upon receipt of the CHANNEL REQUEST message, BSC allocates signaling channels, and sends a CHANNEL ACTIVATION message to BTS (OK)
4.Upon receipt of the CHANNEL ACTIVATION message, BTS selects specified channel, and sends a CHANNEL ACTIVATION ACKNOWLEDGE message to BSC (OK)
5.BSC sends an IMMEDIATE ASSIGNMENT COMMAND message to MS via BTS(OK)
6.MS sends an SABM frame for establishing link with BTS. (NOT OK)
After step 6, when MS do not send the SABM, the timer T3101 expires and we get an immediate assignment failure
then at step 7 UA frame is sent by BTS if step 6 is OK and then further steps are OK.
well one more question i want to ask that i have seen in some operators the LU success rate is subtracted from CSSR formula. Is it due to this reason.
Is LU success rate subtracted in your company CSSR formula