Delay-Constrained Capacity of the IEEE 802.11 DCF in Wireless Multihop Networks

Gamal et al. showed that the end-to-end delay is n times the end-to-end throughput under the centralized TDMA scheduling [4] where n is the number of nodes in the network, and defined this relationship as the optimal tradeoff between the end-to-end throughput and the end-to-end delay. The main purpose of this paper is to show whether this tradeoff relationship is established when IEEE 802.11 DCF is used. We mathematically express the end-to-end throughput and the end-to-end delay as a function of carrier sensing range and packet generation rate. We optimally control them in order to derive a delay-constrained capacity, the maximum value among the end-to-end throughput in which the end-to-end delay requirement is satisfied. As a result, we show that IEEE 802.11 DCF can establish the optimal tradeoff relationship in [4]. This indicates that the optimally controlled parameters can compensate the loss from the difference between the centralized TDMA scheduling and IEEE 802.11 DCF.