Synchronous Multi-Link Access in IEEE 802.11be: Modeling and Network Sum Rate Optimization

Multi-link operation is considered to be one of the new key features in the next generation WiFi 7, i.e., IEEE 802.11be. This paper studies the maximum network sum rate of a general M-link 802.11be network with two different synchronous multi-link channel access methods being proposed by Task Group BE, i.e., Longest Backoff and Shortest Backoff. By using a Markov renewal process to model the behavior of each Head-of-Line packet, explicit expressions of the maximum network sum rate and the corresponding optimal initial backoff window sizes are derived, and verified by simulation results. The analysis shows that Longest Backoff and Shortest Backoff achieve an identical maximum network sum rate. However, to achieve the performance limit, the initial backoff window sizes need to be adaptively tuned in a different manner under the two access methods. As the number of links grows, the initial backoff window size with Longest Backoff should be monotonically decreased, while that with Shortest Backoff should be enlarged.