An effective scheme for energy efficiency in mobile wireless sensor networks

In wireless sensor networks, each sensor node is normally powered by batteries without replenish. Radio operations of a sensor node is a big user of the limited energy. This situation is further exaggerated by retransmissions caused by a time-varying channel. Therefore, how to design an energy efficient sensor MAC is one of the most important issues in sensor networks. Unlike other reported work utilizing a fixed frame size, we propose a new approach to enhance the energy efficiency by introducing an optimal frame size predictor into the sensor MAC, combating the unfavorable time-varying channel quality. We also propose a new sensor MAC to balance goodput performance and energy efficiency, as well as keep fairness among different nodes. Simulation results show that the proposed sensor MAC can largely reduce the average number of transmissions. Therefore, the energy efficiency can be improved by at least 10%, still keeping the same good throughput performance. The proposed sensor MAC can be easily implemented in practical.