Key Takeaway

HiCellTek measures real-time VoLTE voice quality using the Google ViSQOL ML engine (ITU-T P.863 compliant) directly from an Android smartphone. L3 decoding exposes IMS/SIP signaling, RTP stream statistics, and AMR codec negotiation, giving QoS teams end-to-end visibility from RF to application layer in a single tool. Key modules: VoLTE QoE, L3 Decoder, RF Monitor.

Use Case VoLTE IMS QoS ITU-T P.863

VoLTE Quality Assurance with HiCellTek

QoS teams need to measure voice quality across the network, identify VoLTE call drops, codec issues, and SIP signaling failures in the field. This use case shows how HiCellTek provides full-stack VoLTE diagnostics, from RTP jitter to IMS registration, on an Android device.

The VoLTE quality assurance challenge

Standard

ITU-T P.863 / 3GPP TS 26.114

Codec

AMR-NB, AMR-WB (EVS optional)

Transport

RTP over IMS (SIP/SDP)

Failure modes

Call drops, jitter, wrong codec, SIP errors

VoLTE (Voice over LTE, 3GPP TS 22.173) carries voice as IP packets over the IMS core. Call quality depends on multiple layers: LTE radio conditions (RSRP, SINR), QCI 1 bearer integrity, RTP packet loss and jitter, AMR codec negotiation via SDP, and correct IMS registration and SIP session handling. When voice quality degrades, isolating the root cause requires visibility at every layer simultaneously, something legacy tools rarely provide without a full drive test rig.

MOS measurement in the field

Subjective Mean Opinion Score (MOS) per ITU-T P.800 is difficult to scale. Objective models (PESQ/ViSQOL) require specialized hardware or are locked to lab environments in legacy tools.

Correlating voice quality with RF

A degraded MOS score in isolation does not reveal whether the cause is low RSRP, a QCI 1 bearer issue, RTP jitter, or a SIP signaling anomaly. Separate tools mean separate datasets that are hard to correlate.

SIP signaling visibility

IMS/SIP messages (REGISTER, INVITE, 200 OK, BYE) are encrypted at the application layer and not exposed by standard network monitoring tools. Diagnosing SIP errors requires protocol-level decoding.

AMR codec negotiation

Operators define preferred AMR-WB/NB mode sets via SDP negotiation. Verifying that the UE and network agree on the correct codec (per 3GPP TS 26.103) requires SDP inspection during call setup.

The HiCellTek solution for VoLTE QA

HiCellTek integrates voice quality measurement and protocol decoding in a single Android app, giving field engineers end-to-end VoLTE diagnostics without a laptop or external analyser.

VoLTE QoE

Real-time MOS measurement using the Google ViSQOL ML engine, compliant with ITU-T P.863. Video MOS per ITU-T P.1204.3. RTP statistics: packet loss, jitter, latency per RTCP-XR. Displayed per call, per segment, and over time.

L3 Decoder. IMS/SIP

Live decoding of IMS signaling: SIP REGISTER, INVITE, PRACK, UPDATE, BYE, and error responses (4xx/5xx). SDP body parsing shows AMR codec mode sets, ptime, and media attributes negotiated at call setup.

L3 Decoder. RRC/NAS

Concurrent RRC and NAS decoding reveals QCI 1 DRB configuration, EPS bearer setup/release, and handover events correlated with voice quality events. Identifies radio-layer triggers for call drops.

RF Monitor

Simultaneous RSRP, RSRQ, SINR, and CQI monitoring during calls. Correlate voice MOS degradation with serving cell changes, low SINR zones, and frequency band transitions in real time.

VoLTE QA workflow

Collect MOS in field

Place and receive VoLTE calls while HiCellTek records per-call MOS (ViSQOL), RTP jitter, and packet loss across the test route.

Correlate with RF

Overlay MOS timeline with RSRP/SINR and handover events. Identify geographic zones where voice quality falls below operator thresholds.

Decode IMS signaling

Inspect SIP INVITE/200 OK SDP to verify AMR codec negotiation. Review RTCP-XR reports and check for SIP error responses indicating network issues.

Export reports

Export per-call MOS statistics, RTP KPIs, and decoded SIP flows to Excel or PDF. Data includes GPS timestamps for geolocated quality maps.

Key metrics measured

MOS score

Per-call and per-segment objective MOS via ViSQOL (ITU-T P.863 compliant)

RTP jitter

Inter-packet delay variation per RFC 3550 / RTCP-XR (RFC 5725)

Packet loss

RTP packet loss rate and burst loss statistics per RTCP-XR

AMR codec mode

Active AMR-NB/WB mode and mode set negotiated in SDP (3GPP TS 26.103)

SIP call flow

Full SIP dialog: REGISTER, INVITE, PRACK, UPDATE, BYE and error responses

QCI 1 bearer stats

DRB setup/release events and QCI 1 EPS bearer configuration from NAS decoding

Who is this for?

QoS teams

Network quality engineers monitoring VoLTE KPIs across the operator footprint and investigating voice degradation complaints.

VoLTE optimization engineers

RF and core teams troubleshooting VoLTE call drops, codec mismatches, and IMS registration failures during network optimization.

Regulatory auditors

Auditors verifying operator compliance with QoS obligations for voice service under national regulatory frameworks.

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Start measuring VoLTE quality

Get full-stack VoLTE diagnostics. MOS, RTP, IMS/SIP decoding, directly from an Android smartphone. No external analyser required.

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