SHUSH: Reactive Transmit Power Control For

Asymmetric transmission ranges caused due to transmit power control have the undesirable effect of increasing the number of hidden terminals in the network as well as increasing the unfairness in channel access. In this paper we present a new reactive power controlled MAC protocol, SHUSH, which tackles the above problems. We compare the performance of SHUSH with four other transmit power controlled MAC protocols and demonstrate that SHUSH achieves superior ag- gregate goodput, spatial reuse, fairness, and minimal energy consumption. I. I NTRODUCTION Transmit power control is a highly effective technique for minimizing interference and energy consumption in wireless networks. If two communicating nodes can lower their trans- mission powers and corresponding transmission radii to the minimal values that maintain communication between the two nodes, then the transmission between the two nodes will minimize interference with other nodes, enabling higher aggregate throughput and greater spatial reuse than wireless networks that lack power control (19). Transmit power control has further value in terms of minimizing energy consumption due to transmission. Portable wireless access devices such as laptops, PDAs, and cell phones have extremely limited battery lifetimes. Energy constraints are also severe in wireless sensor networks. Transmit power control offers an effective technique for prolonging the lifetime of these wireless access devices by communicating at the minimum power that still maintains