Channel Access in Multi-rate Wireless LANs: A Peak Age of Information Perspective

Abstract In this study, we comparatively assess several channel access mechanisms for information sources that transmit age-sensitive status update packets over multi-rate IEEE 802.11 wireless LANs. For conventional data traffic, the legacy channel access mechanism imposed by the Distributed Coordination Function (DCF) allows sources to access the channel equally and this leads to a throughput-fair bandwidth allocation which is known to give rise to the performance anomaly problem. To mitigate this anomaly, airtime-fair channel access methods have been proposed. Recently, status update systems have attracted the attention of researchers for which information freshness metrics derived from Age of Information (AoI) or Peak AoI (PAoI) have been shown to be more effective instead of conventional performance metrics such as throughput, delay, or loss. In this paper, we propose a novel channel access mechanism for age-sensitive traffic, called System PAoI-based Channel Access (SPCA), which is devised to reduce the mean PAoI averaged over all the contending sources, termed as the system PAoI.We show through simulations that SPCA effectively reduces system PAoI compared to existing throughput-fair and airtime-fair channel access mechanisms.