SDCCH Drop Call Reason

SDCCH Drop Call Reason

Low Signal Strength on Down or Uplink
The reason for poor coverage could be too few sites, wrong output power, shadowing, no indoor coverage or network equipment failure.
Action: Check coverage plots.Check output power. Perform drive tests. Check BTS error log
Solution: Add new sites. Increase output power. Repair faulty equipment.

Poor Quality on Down or Uplink
Action: Check C/I and C/A plots. Check frequency plan. Perform drive tests.
Solution: Change frequency. Use available radio features.

Too High Timing Advance
Action: Check if the cell parameter TALIM is < style="font-weight: bold;">Solution: Set TALIM to a value close to 63. Tilt antenna/reduce antenna height/output power, etc. for cochannel cells.

Mobile Error
Some old mobiles may cause dropped calls if certain radio network features are used. Another reason is that the MS is damaged and not working properly.
Action: Check MS fleet.
Solution: Inform operator.

Subscriber Behavior
Poorly educated subscribers could use their handsets incorrectly by not raising antennas, choosing illadvised locations to attempt calls, etc.
Action: Check customer complaints and their MS.

Battery Flaw
When a subscriber runs out of battery during a conversation, the call will be registered as dropped call due to low signal strength or others.
Action: Check if MS power regulation is used. Check if DTX uplink is used.

Congestion on TCH
The SDCCH is dropped when congestion on TCH.
Action: Check TCH congestion
Solution: Increase capacity on TCH or using features like Assignment to another cell, Cell Load Sharing, HCS, Dynamic Half-Rate Allocation and FR-HR Mode Adaptation etc