A Combinatorial Approach to the Optimization of the Channel Utilization Ratio in Ad Hoc Wireless Networks

In this paper, after formalizing the concept of channel utilization ratio (CUR) in ad hoc wireless networks, we investigate its impact on the network performance. Given that a node can hold a multi-hop route for a time interval defined as reserved channel utilization interval (RCUI), we assume that the node effectively utilizes the reserved route for an interval defined as effective channel utilization interval (ECUI), the duration of which corresponds to the duration of the message to be transmitted. This models a realistic scenario, where a node may use the shared radio medium for only a portion of the reservation interval. Defining the CUR as the ratio between the durations of the RCUI and the ECUI, we develop a combinatorial framework which leads to the optimization of the CUR for maximizing the effective transport capacity, which represents the actual bandwidth-distance product carried by the network. We also show that the way, either continuous or discontinuous, in which a node transmits its message entails minor performance differences, indicating clearly that the CUR is a meaningful network performance indicator.