1. How to Analyse SDCCH drop due to "Other Reason"
SDCCH drop
SOLUTION:
CONDITIONS:
PROCEDURE:
Our experience says that the "Other Reasons" is the area which is
Really difficult to point out as there could be various possibilities
of the same.
There is list of some possibilities that has to be taken care while
analysing the SDCCH drop:
1.Hardware Fault at BTS
For BTS, HW fault should be the prime and preliminary point to be
concentrated. This can be seen by collecting The OMT Logs of CF,TRX,
ECU etc. This type of fault could also be intermittent in nature.
2.Definition of Parameter
Wrong definition or parameter in the BSC could lead to this type of
fault.
Few important ones are as follows
The MS power control and BTS power control : As the MS and BTS powers
Are regulated in order to decrease battery consumption of the MS and
not to saturate the multicoupler of the BTS as well as decreasing the
Interference in the system.
So the fine tuning of the control parameters are very important in
accordance with R&D recommendation.

2. Activation of Adaptive configuration : This could also be the reason
For the SDCCH drop. So proper R&D consultation is needed before
activating the same, if required . It is advisable to use of this only
in those cells which are really needing the same not the entire BSC
area.
3.DIP Status
DIP with poor quality may lead to drop call problem in different cells.
Poor quality may implicate High BER or Frame Loss in the DIP connected
to a site. DIP Quality Supervision tools should be initiated for the
suspected connecting Digital Path. Mismatch of DIP could be another
reason behind drop call occurrence in some of the cell.
4.frequency Interference Problem
Interference is generally related with Quality Drop, but sometimes it
May provoke Sudden Drop as per situation.
5.C7 link
The C7 link between BSC to MSC should be properly dimensioned and check
The command C7ERP for SCCP information.
Stability of C7 link
6.Proper definition of MSC parameter
The main functions of SDCCH are as follows :
-Call Setup
-Paging

3. -Location Updating
-Authentication
-Ciphering
-SMS
-IMEI Check
As we could see above, the MSC is also very well involved in above
functions so it is equally required to check MSC part also while
analyzing the SDCCH drop. Few important parameters definition are given
below :
1.The Exchange properties IMEICONTROLSMS and IMEICONTROLSS to "0" (No
IMEI related checks ON if you don't have a EIR),
2 PHASE2-1 in the BSC parameters in MSC (MGBSP).
Same as above, we may also check the parameter related to Location
updating, SMS, ciphering , authentication etc.