VoNR quality issues: MOS < 3.0, jitter, delay, codec problems

VoNR Quality Metrics

VoNR quality issues manifest as poor voice clarity, choppy audio, echoes, or one-way audio. The primary metric is MOS (Mean Opinion Score) on a 1-5 scale: above 4.0 is excellent, 3.5-4.0 is good, 3.0-3.5 is fair, and below 3.0 is poor. Jitter (variation in packet inter-arrival time) causes audio artifacts when exceeding the jitter buffer capacity, with a target below 30 ms. The UE and IMS media gateway maintain 20-60 ms jitter buffers to smooth variations. Excessive jitter results from inconsistent gNB scheduling of voice packets, backhaul congestion with variable queuing, or core network…