On Spatial Reuse and Capture in Ad Hoc Networks

Neighbors of both the transmitter and the receiver must keep quiet in a 802.11 wireless network as it requires bidirectional exchange, i.e., nodes reverse their roles as transmitters and receivers, for transmitting a single DATA frame. To reduce role reversals and to improve spatial reuse, a piggybacked acknowledgment based approach has been proposed to enable concurrent transmissions. Recent findings on physical layer capture show that it is possible to capture a frame of interest in the presence of concurrent interference and that the SINR threshold is dependent on the relative order in which the frame and the interference arrive at the receiver. In this paper, we show that it is possible to exploit capture and increase concurrent transmissions in wireless adhoc networks. We develop a distributed channel access scheme and demonstrate that it offers significant throughput gain particularly at lower data rates.