SDCCH Drop Problem

[atese]

Hi Taki.

Try to check this:
1. timing advance of cell in urban areas, if you have exssesive propagation try to fix it by downtilt, many times the SDCCH drop is originated by some co-channel co-bsic that meet in long distance.
2. Check the rxLevAccesMin and try to set it no more than -102 dB, sometimes we force the mobiles to get the cell in poor RF conditions, around -110. This a SDCCH DC by lost of radiolink during signaling phase.

[kais]

chek this case :


SD DROP RADIO rate is HIGH then

IF SD DURATION AVG > 6 PER TRX;

--------> A TRX HARDWARE PROBLEM ( RESET AND/OR REPLACE TRX)

[nabil el haddani]

Probable Reasons of Drops on SDCCH :

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 < 63. Check if the co-channel cells are over-heard.
Solution: Set TALIM to a value close to 63. Tilt antenna/reduce antenna height/output power, etc. for co-channel 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 ill-advised 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.

[capcipcup]

i think maybe u can change sdcch kanal to the best kanal at that slot

how do we know which one is the best kanal ?

[diankestiwi]

how do we know which one is the best kanal ?

as i know we can use batrana for siemens ( and we can calculate from the statistic data ) so we compare each kanal where are better than other.

[kadou26]

Please every body i want to know what mean this two sentence
"SDCCH lost radio connections (error indication) "
"SDCCH lost radio connections (connection failure)"
in Huawei system (BSC) and I to resolve it.
it's the most important SDCCH drop reason in our network that affect seriously the CSSR

Thanks

[capcipcup]

as i know we can use batrana for siemens ( and we can calculate from the statistic data ) so we compare each kanal where are better than other.

would you tell me which statistic data should i get
thanks

[kadou26]

Ok Thank to all

[mp9413]

Hi,

Abis trace would be useful. Observe the messages flow and identify the abnormal release in SDCCH should give you some hints.

mp

[OptimiNSN]

Dear I recommend that you sent us the report ND204 of the BSC or BTS, who have problems, so we can help you.