Experimental Evaluation of IEEE 802.11ax - Low Latency and High Reliability with Wi-Fi 6?

Abstract

IEEE 802.11ax, also named Wi-Fi 6, introduces significant enhancements to the channel access mechanism. The introduction of orthogonal frequency-division multiple access (OFDMA) and the more centralized channel access coordinated by the AP can potentially improve the latency and reliability performance of Wi-Fi 6 compared to previous Wi-Fi generations. This would make Wi-Fi systems suitable also for more demanding applications, e.g., in the industrial domain, which require low communication latency with high reliability. However, only few works exist that evaluate these new features with regard to such applications. This work presents a comprehensive measurement study on the latency and reliability performance of Wi-Fi 6 and compares it to performance of Wi-Fi 5. The baseline scenario measurements reveal a significant latency reduction of Wi-Fi 6 compared to Wi-Fi 5 especially for larger number of stations and especially in uplink direction. Since Wi-Fi 6 operates in unlicensed bands like its predecessors, the influence of interfering networks on the communication performance is an important aspect. Our evaluation shows that interfering traffic can significantly increase the latency and packet loss experienced by Wi-Fi 6 for smaller operation bandwidths, while for larger bandwidth of 80 MHz and resulting lower relative network load Wi-Fi 6 can still provide 99-percentile latency below 10 ms in the evaluated scenario. Overall, the achieved results with Wi-Fi 6 are promising, but further evaluations especially on the effect of different OFDMA scheduling algorithms and configurations is needed to evaluate its potential for demanding applications.