- This topic has 23 replies, 1 voice, and was last updated 10 years, 3 months ago by Ardhendu.
7th November 2008 at 07:00 #54501PanGuest
Circuit Identity Code is a traffic chanel id on A-interface and valid between MSC and BSC only. By knowing CIC MSC or BSC may correlate each signalling message from other peer on A-interface with appropriate call. There is switching matrix in BSC similar one in MSC but smaller. It is BSC related task to switch subslot on A-bis interface to subslot on A-ter interface (timeslot on A-interface) only during call time. There is no permanent static mapping a radiointerface TCH to A-interface TCH.7th November 2008 at 10:52 #54502SachinGuest
I had thought so also earlier. But CIC is an optional value. If suppose it is not provided in Assignment Request message, how would the DSC will then know which TS/Channel to provide for a call on E1 card? There must be some sort of static mapping required.
Sachin8th November 2008 at 06:07 #54503PanGuest
Yes, it is optional parameter, but if MSC requests TCH from BSC for speech call then terrestrial circiut (CIC) also must be allocated in Assignment Request. This CIC is correlated in BSC with Local Reference and TCH after TCH assignment. Using this information BSC switches the CIC with A-bis subslot assosiated with allocated TCH.10th November 2008 at 03:45 #54504SachinGuest
Thus, to summarize, we cant have a static mapping of Abis timeslot to E1 timeslot? Is it?
Sachin10th November 2008 at 10:44 #54505PanGuest
There is no meaning to have a static mapping because number of TCH on radiointerface > number of TS on A-interface. There is low probability that all TCH on all BTS will occupied simultaneously. And BSC must to support concentration function similar one Access Network (e.g. V.5.2) does in PSTN.11th November 2008 at 03:36 #54506SachinGuest
Sachin25th November 2008 at 11:49 #54507khalidGuest
i want to kno how can i give diffrent device chanel in e1 such like fox or RTU15th March 2010 at 07:27 #54508MOHSENGuest
WHAT MEANS CIC IN WHEN INTERFACE CONTAIN COMPRESSED (AMR,EFR,FR,…) SOUND?10th January 2011 at 08:12 #54509ArdhenduGuest
Please let me know what will be the behavior of BSC if it receives 2 assignment request with different CIC on the same SCCP connection.