Probable Reasons
· No Response to Immediate Assignment
One reason why the MS does not respond to the immediate assignment could
be low signal strength.
Action:
– Check dropped calls due to low signal strength.
– Check ratio of calls disconnected at low signal strength.
Solution:
Improve coverage.
· High Interference
Action:
– Check Interference Þ chapter 12.
Solution:
Perform a frequency reallocation.
· Random Access Burst from Another Co-Channel, Co-BSIC Cell
Action:
– Check BSIC and frequency plan Þ chapter 15.
Solution:
Change BSIC or frequency.
· More than one RA burst send from a mobile during one call setup
Action:
– Check downlink interference.
– Check related parameters: ACCMIN, MAXRET, TX
Solution:
Change frequency and parameters.
· Phontom Random Access
Some noise is interpreted as Random Access burst, but no SDCCH will be
allocated to it.
Action:
– Field measurement
· BTS handware or link failure
Action:
– Check BTS error log
· Power balance problems
Action:
– Check power balance related parameters
Solution:
Change paramters.