Optimizing Backoff by Dynamically Estimating the Number of Nodes in Multi-hop Adhoc Networks

Wireless local area networks (WLANs) have become increasingly popular and widely deployed. The medium access control (MAC) protocol is one of the important technologies in WLANs and directly affects communication efficiency. In this paper, we focus on the MAC protocol and propose a novel protocol in which network nodes dynamically optimize their backoff process to achieve high throughput in multi-hop adhoc networks. The distributed MAC protocol has the advantage of not requiring infrastructure such as an access point. However, under high traffic loads, the total throughput significantly decreases due to the hidden node problem, which needs to be improved. Through theoretical analysis, we find that the average idle interval can represent the current network traffic load and can be used together with estimated number of neighbor nodes and hidden nodes for setting optimal contention window (CW). Through simulation comparisons with a conventional method, we show that our scheme can greatly enhance the throughput and the fairness in the saturated case.