Naslov
Practical cross-layer testing of HARQ-induced delay variation on IP/RTP QoS and VoLTE QoE

Autori
Lipovac, Adriana ; Lipovac, Vladimir ; Grbavac, Ivan ; Obradović, Ines

Izvornik
EURASIP journal on wireless communications and networking (1687-1472) 2021 (2021), 1; 1-18

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
VoLTE ; Voice QoE testing ; Protocol analysis

Sažetak
As the PHY/MAC-layer IR-HARQ and RLC-layer ARQ error recovery procedures, adopted in LTE, may impose additional delay when their code-block retransmissions occur, the arising question is whether these significantly contribute to IP and consequently RTP packet delays, and finally degrade the overall application-layer end-to- end QoE, especially when voice is transmitted over LTE? With this regard, we propose and demonstrate a VoLTE QoS and QoE test procedure based on PHY/MAC/RLC/IP/TCP- UDP/RTP cross-layer protocol analysis and perceptual speech quality QoE measurements. We identified monotonic relationship between the paired observations: QoE and HARQ RTT, i.e. between the PESQ voice quality rating and the IP/RTP packet latency, for given BLER of the received MAC/RLC code- blocks. Specifically, we found out that, for the HARQ RTT value of about 8 ms, only up to 2 HARQ retransmissions (and consequently no RLC- ARQ one) is appropriate during any voice packet, otherwise delay accumulation might not be accordingly “smoothed out” by jitter/playback buffers along the propagation path.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika, Računarstvo

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