Practical cross-layer testing of HARQ-induced delay variation on IP/RTP QoS and VoLTE QoE (CROSBI ID 295702)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Lipovac, Adriana ; Lipovac, Vladimir ; Grbavac, Ivan ; Obradović, Ines
engleski
Practical cross-layer testing of HARQ-induced delay variation on IP/RTP QoS and VoLTE QoE
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.
VoLTE ; Voice QoE testing ; Protocol analysis
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Podaci o izdanju
2021 (1)
2021.
1-18
objavljeno
1687-1472
1687-1499
10.1186/s13638-021-01970-y
Povezanost rada
Elektrotehnika, Računarstvo