But then this a lack of scheduling resources…
Do you have SPS active to save some PDCCH in Downlink?
Yes SPS is active.
Then you must spread the traffic better among cells and layers of same sector and between neighbouring cells.
Mute call is usually occurring if high number of sequential VOLTE packet dropped which could be caused mostly by RLF during mobility scenario.
Interfrequency should be reduced during railway by maintaining the qci 1 traffic on single carrier to avoid frequent transition if several carrier used, this could be achieved through optimized service-based handover where handover could be restricted on qci 1.
For intra consider faster handover triggering to avoid handover due to late scenario consider lower time to trigger for early triggering to a3 if you have more static user consider SF medium tuning.
Also consider checking drx implementation if is off VOLTE packet should be expected on every 20 ms so avoid larger drx cycle.
Some SW vendors implement less robust SIB coding leading to frequent RLF during mobility due to poor SINR a point to consider as well.
We have done physical optimization and load balancing on layers.
But still problem is not fully resolved.
We have done following action
- Layer balancing by phsyical optimization 90% VoLTE traffic on FDD band and rest on TDD.
- Quality based HO for VoLTE calls.
- Early exit of calls from highly interfered band to clean band.
- VoLTE muting detection and mitigation feature is activated.
- SPS is activated.
Apart from this any other suggestions…?
TTI bundling?
RLC segmentation?
ROHC is on?
Yes TTI bundling and ROHC is active.
And RLC segmentation needs to check.
First identify what is the reason for muting.
Is it due to poor RF?
Or PDCCH congestion (sceduling delay)?
Or backhaul issue?
Or handover interruption time is very high and number of handovers are very high?
Poor RF? Optimize it. Have proper coverage planning
PDCCH congestion? Try load balancing. If done, then try disabling high aggregation levels (AL8).
Add capacity if required.
PDSCH congestion? Less likely to occur, but if it is there, add capacity.
Backhaul issue? Check GTP losses. Correct BH if any issue.
Handover interruption time and many handovers? Plan the the railway station such that single dominant cell is serving. reduce the handovers.
If RF condition is overall better, then increase HO margins.
If HO failure is higher then optimise RACH parameter etc.
2 Likes
In case cell is having high muting due to high CCE failure, can we change cfi=adaptive to cfi=fixed 3 symbols to reduce cce failure?
You can try.
But if CFI adaptation algorithm is efficient enough, then we might not get any additional benefit.
Rather peak throughput would get reduced.
Yes, that’s the risk.