tch drop
DESCRIPTION
Tch dropTRANSCRIPT
TCH Drop: Reason & Solution
Drop during conversation is known as TCH drop. It takes place after connect ACK msg on TCH.TCH drop occurring.
For TCH drop first cross check the BCCH of that cell, hardware issue may be, change RXP and RLT value. Find out there is any interference ,neighbor defined.
Reasons for TCH Drop: Wrong Parameter Planning.
BAD HOSR.
Hardware Fault.
High TR Fail.
Overshoot.
Outage.
Due to Low Coverage.
Due to ICM Band(CDMA)
Solutions for removal of TCH Drop:Check Parameter: Check the BCCH Plan (C/I or C/A), Co-BSIC & Co BCCH.
Check the Timer T 100(should be 20 ms)
Check Overshooting: If a cell is picking call from long distance, Check the sample log according to TA..
Site Orientation.
Effective tilt should be check.
Mount position should be check
Improve HOSR: Check the Hopping plan.
Check the Neighbor Plan
High TR Fail: Check and clear TR fail from oss end.
Check HW: Check Alarms on site.
Check TRXs,Check Slips.
Check the Hopping plan.
Check BB2F card., Check VSWR,
Path imbalance,Connector, Connection,Check TMA
HOSR : Reason & Solution
Hand over success rate:If HOSR will be good TCH drop will also be good.If Handover success rate degrades call drop rate will take place.
Reasons for HOSR: Improper Neighbor planning.
CO-BCCH-BSIC issues in Neigh.
Parameter Check.
HSN clash.
SL value.
LAC boundary.
DAC value mismatch.
Syn mismatch.
Overshoot.
HW Issues.
Low Coverage
Neighbor Tuning: Try to retune neighbors
Avoid CO-BCCH-BSIC neighbors.
Avoid extra neighs.
Delete long distance neighs.
Check neighs are defined form both ends.
If there are high fail delete and recreate neighs
Parameter Check: Retune SL.It can change bw -90,-95,-105.
Check HSN.
Check SYN.
Retune LDR, LUR, IDR, IUR.
Retune LMRG, QMRG, PMRG.
SDCCH Blocking? Find Solution
SDCCH is a dedicated channel which is using for LAC updation, Call setup, SMS in idle mode. It works in UL & DL.
SD blocking means that you are not getting SD resource for the call origination. When MS connects with NW then RACH and AGCH are provided. After AGCH,SDCCH is provided but if SDCCH is not provided at this time due some problems or due to unavailable of SD by BSC ,its called as SD Blocking. There are no of reasons for that.If such a case arises the customer will not be able to originate any call.
Difference Between Blocking and Congestion:It is very important to know difference between blocking and congestion. Some people think that both are same, but they differ from each other. If all the SD resources are full and not available for SD assign then its come into congestion. If at a particular time call is attempted and it fails then it known as Blocking.
Reasons for SD Blocking:Some of them are-1. LAC boundary.2.HW Prob.
Solutions for removal of SD Blocking:Here are some steps by which we can reduce SD Blocking-
Check the No. of SDCCH channel Available, if less then increase SD channel taking care that there is no TCH Blocking.
Check LAC boundary, If location update is more then change the LAC of that site and set C2 and HYS.
Use of Dynamic SDCCH (It is a BSC parameter and will be applied on whole BTS).
Hardware check / shift SD to new time slot
Some times BMA and HYS parameters are useful to remove SD Blocking.