Hi Experts,
I am getting High Packet loss Rate in QCI-1 for both UL & DL in Volte KPI.
What can be the reasons & how it can be rectified.
- Link Congestion
- Bad Coverage / Quality
- Transmission
- Hardware
- Cpri cable
- VSWR, RSSI
- Ethernet Cable connection
PDB timer value?
High overlapping or threshold set wrong for qci1 dl/ul bler leading to packet discard at high rate.
Can check tdiscard timer.
Sinr in DL/UL main culprit for high packet loss, considering TX end no issue for packet loss.
Hi Guys.
What’s the main reasons of PDCP Pkt Lost Ul on Qci 1, for VoLTE?
Network Congestion, Radio Signal Issues, Mobility and Handover Issues…
Any other reasons?
Max TX power 23 dBm reached.
Try to activate TTI bundling, it will reduce UL pkt loss qci1.
This feature is already active.
Do you also see equivalent higher packet loss at RLC and MAC layer?
There are no RLC retransmissions for QCI1 only MAC retransmissions.
Issue is your link budget is always Uplink limited and you activate SRVCC too late.
This is why UE is often at max tx power.
That will work when UE is in weak coverage and bypass the HARQ.
Check RLC Retansmission.
Check RLC Features.
Try to move the traffic towards high capacity band or enable the SRVCC.
Oh yes you are right.
I was thinking if there are more RLC ReTx and MAC ReTx then this might be coverage problem and if not then some other protocol problem.
But sounds like coverage issue.
Yes, maybe problem is it on indoor Coverage, maybe steering traffic to Layer where coverage is higher… Low Band…
More loss is on cities with more density building.
Don’t do SRVCC at -122 dBm.
Try to do it earlier.
MAC Layer is bigger than RLC.
Operator Strategy is more retention on LTE network.
Trying to do it earlier maybe will be a problem…
You have to make up your mind: you either want retention or QoE.
You do not have enough coverage for both.
Your qrxlevmin may be too low like -126 dBm.
It is a big challenge to customer… I agree with you. 
But, third world countries is the big challenger Budget for Network expansion.
Thank Guys for this good discussion.!!!
There is an argument on why Voice needs to be on 4G at all at such poor coverage!
At -120 Voice quality is too low.
Keeping Voice call at such coverage levels isn’t useful at all for network and for user.
Better to off load to 2G and save resources.
Keeping 4G traffic for data makes more sense.
There are features that trigger interfreq HO based on UL SINR or based on UL TX power.
This will help steer the traffic to lower bands.
Totally agree with you.
Yes, already active in the network, MCPC with UP link and Down Link.
Service Triggered Handover features are very handy and successfully steer VoLTE traffic towards low-band carriers.
This is especially beneficial in TDD-FDD deployments, where shifting the traffic away from TDD(Weaker Uplink) gives a significant boost to VoLTE quality.