VOLTE Mute call Increased

4G LTE
,
1

Dear Experts,

VOLTE Mute call Increased in our NW Post Carrier BW Change from 5Mhz to 10 Mhz. i have done the sample checks and found that Cells which are having High Mute call are radiating with 12.2 dbm (40 W RRU) RS Power while Previously they were radiating with 15.2 dbm (80 W RRU) RS power . there is no impact on cells where RS Power is same as Before i.e 15.2 dbm.
Now there is no option to change Power on Cells which are radiating with 12.2 dbm due to RRU Power Limitation(40 W). I am Uptilting the antenna as an interim measure to compensate the coverage loss… But what Other Parameter i can look into to Improve Mute calls.

thanks
Govind Dahiya

2

You can check below suggestion

3

Thanks for the input.
Will Uptilting the Impacted Band Will compensate the coverage loss due to Reduction in RS Power from 15.2 dbm to 12.3 dbm.

4

When you double the bandwidth, your RRU transmit power should double if the power spectrum density is same as before. But now your power is limited to 40w, i.e., 46dbm not 12.2dBm, the power spectrum density is only half as before, thus Rx SINR is only half as before.
If you can improve coverage by uptilting the antenna, it means you can improve VOLTE mute call by employing advanced Tx beamforming technique in Rel14.

5

@Wendy Thank You very much.

Actually 12.2 dbm is not the Total RRU Power its’ a Reference signal Power for 4 Port Antenna. Reference power was 15.2 dbm Prior to BW Augmentation.

Yes Mute call reduced Post Antenna Uptilt… But It;s still Degraded as compare to Pre Value.
Advance TX Beamforming Means Transmission Mode 7?

6

Dear Experts.
Does high number of intra handover in LTE can be the reason of mute calls?
I am trying to optimize cells with high mute call count and primary reason seems to be high intra HO count.

7

When you say mute: is it one way RTP packest are missing or both ways RTP packets are missing?

8

In both the case its pegged as mute calls.
Actually counter which we are getting is total number of mute calls and mute callincallout- i.e mute call during Handover.

9

If you have long trends you can correlate “intraf ho att” with “mutecallsout” and see whether there is obvious trends
Also maybe correlate it with hosr or pingpong ho.

10

Features like Data Forwarding at Intra-LTE Handover or Packet Forwarding at S1 HO will reduce the packet loss (in VoLTE late packets are regarded the same as lost) in DL direction at an intra-LTE handover during a voice session.
Packet loss either in UL or DL or both causes your mute calls.

11

Experts:

I am facing high mute call issue on small cells, which are operating on TDD band.
A1/A2 are set -70/-75 and having sufficient overlapping with macro sites (operating on TDD/FDD band).

Any suggestion to improve high mute calls?

12

What is your A3 offset?
Try to disable it using 15 dB to avoid ping pong and mute call improvement during Freq HO.

A2 set too early what’s A5 value used for serving and target.

13

A3.
Same band-3 dB.
Fdd1-3 dB.
Fdd2- 3 dB.
Only A3 based HO A5 not used.

14

Generally A3 used to disabled.
A5 preferred.
I mean for VoLTE strategy, not for PSHO.

Others can comment.

15

A5 is considered more safer HO but it is also more costly (time, battery, cell planning).

A3 is more aggressive HO as it let’s the device go as soon as serving cell is in poor state.

16

Here for VoLTE A3 based HO is used.

Will tunning A1/A2 help early HO by setting A1/A2 -50/-55?

17

Dear experts what can be the possible actions to improve VoLTE mute calls?

Can we change Interfrequency HO triggering from A3 to A5 based event.

Any parameter which can be changed to improve the same?

Vendor is Samsung.

18

What is the reason for mute calls, 1st need to identfy.

Is it only on bad coverage or is it on particullar cell all the time?

In my view for Interfrequency better to enable only A5 based.

19

In my experience either the playing UE is at max Tx power or recording UE is with bad SINR (negative SINR).

Keep in mind for VoLTE there are no RLC retransmissions just max 4 HARQ retransmissions.

20

High number of handovers on cells serving along the railway track, specially during busy hours.

In Mumbai India trains are crowded during bssy hours and at the same time high mute calls observed.

Mainly there is a case of UE radiating at Max Tx power.