VOLTE MUTING

Introduction & Definition of VoLTE Muting:-

As Voice conversations are real time in nature, any gap or break in Voice gives an unsatisfying user experience.

VoLTE muting is basically gap in Voice packets or RTP packets which can be perceived by human ears as a blank voice. By standard practice and simulations, 400ms is set as a minimum duration which can be perceived as Voice Muting.

According to ITU-T G.114

§VoIP users are very satisfied up to 200 ms

§VoIP users are satisfied up to 285 ms

§Most VoIP users are satisfied up to 390 ms

Audio gaps occur when there is continuous packet loss either in the downlink and/or uplink.

Different scenarios: –

-Unstable radio conditions (for a short period of time)

–Unstable radio conditions → Radio link failure → Cell selection → Successful Re-establishment

–Unstable radio conditions → Radio link failure → Cell selection → Rejected re-establishment → Successful resume (service request or tracking area update

Radio Link Failures Causing Audio Gap

Other Failure: Caused by radio link failure = 92%

HO Failure: Handover signaling transmission failure = 8%

Backhaul RCA for VoLTE Muting

i)Backhaul is the combination of multiple media and network elements e.g MW, Fiber, IP backhaul routers, Aggregation routers etc.

ii) First step of segregation should be identifying whether the eNodeB is connected by Microwave or Fibre and then move on with troubleshooting as explained in the following sections

iii) Backhaul analysis reports are scheduled on a daily basis and also can be generated based on query from Mycom Tool

iv) Following categories of reports are used for troubleshooting;

a. IP Backhaul evaluation metrics

b. Microwave links evaluation metrics

c. Transport network evaluation metrics

IP– Evaluation Metrics:

a) Power loss report

b) CRC/interface error report

c) Exception report interface, CPU-Memory utilization, interface error

d) IPSLA report

e) TWAMP Report

f) eNodeB Report (GTP Path loss / Path fail)

Microwave – Evaluation Metrics:

a) Error reports (ES, SES)

b) Modulation reports (Capacity degradations / modulation dip)

c) Utilization / Capacity reports (Throughput /Capacity)

Transport – Evaluation Metrics:

a) Exception reports Client interfaces

b) Exception report for channels (Power level, errors, Q Factor)

c) Exception report OTS losses (Span loss w.r.t. Design loss)

Conclusion:-

Muting elimination Steps:

a) Segregating the issues in the right buckets

b) Carry out the RCA through meticulous correlation between the various domains / reports

c) Appropriate actions as per the defined processes