Throughput and Reliability Analysis of a Scalable Broadcast MAC for Distributed Wireless Networks

In carrier-sense-multiple-access-based distributed wireless networks, the legacy mechanism of arbitrating the access attempts of multiple broadcast users (using a fixed-size temporal contention window consisting of multiple contention slots having uniform selection probability) has been well understood to be inefficient in avoiding collisions, especially when the network is large. Recently, it has been found that this inefficiency can be mitigated by exploiting an additional degree of freedom (DoF) over the contention window, referred to as contention slot selection distribution (CSSD). In this article, the authors examine how the additional DoF contributes to enhancing network performance and quantify the performance gains that the network can achieve in terms of easily understandable performance indicators like network throughput efficiency and broadcast reliability. A discrete-time Markov chain is formulated to characterize the access arbitration process involving a reverse exponential CSSD and its steady-state solution is fed to a renewal-reward process-based network model to estimate the performances of interest. Validated numerical results are presented which confirm that this new channel access arbitration mechanism can significantly enhance the scalability of distributed broadcast networks.