SmartNode: achieving 802.11 MAC interoperability in power-efficient ad hoc networks with dynamic range adjustments

The standard CSMA/CA based IEEE 802.11 protocol assumes that each node uses a certain fixed (or maximum) transmission power for the transmission of each packet. However, a MAC protocol with power adjustments can have significant benefits towards better power conservation and higher system throughput through better spatial reuse of spectrum. In this work, we propose a power efficient MAC layer algorithm, SmartNode, that is compatible with the basic RTS-CTS-DATA-ACK MAC protocol defined in IEEE 802.11. Our algorithm uses the minimum required power level for the transmission of data packets, which requires special handling for the exchange of control packets. Compared with previously proposed power-controlled MAC protocols, our algorithm does not require multiple data channels at the physical layer so that it is able to inter-operate with regular nodes running the existing IEEE 802.11 MAC protocol. Through extensive performance evaluations, we have demonstrated that our proposed algorithm is effective in a power-controlled ad hoc network - it is able to increase system throughput while conserving power with dynamic power adjustments.