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