Investigating the Performance of Power-Aware IEEE 802.11 in Multihop Wireless Networks

Abstract

We address two issues of contemporary interest in the area of enhancing the performance of ad hoc networks, where the IEEE 802.11 distributed coordination function (DCF) is the adopted medium-access control (MAC). We investigate the effects that transmission power control and tuning carrier sensing (CS) threshold have on network throughput, and we study the interplay between them. To accomplish this, we develop a realistic analytical model that characterizes the transmission activities that are governed by the IEEE 802.11 DCF in a single-channel power-aware multihop wireless network. We observe that selecting a smaller CS threshold will severely impact the spatial reuse, whereas a larger CS threshold will yield excessive interference among concurrent transmissions. Accordingly, we discovered that performing power control has either a minor or negligible effect in both situations, respectively. Furthermore, when the CS threshold is selected appropriately, power control shows its effectiveness in reducing collisions and, hence, improving system performance. Finally, using our model, we demonstrate the potential adverse impacts of request-to-send/clear-to-send (RTS/CTS) control packets on the network capacity and compare its performance with the two-way basic access method.