Enhancing energy efficiency for wireless sensor networks

This paper presents enhancements to Medium Access Control (MAC) layer in order to improve energy efficiency for wireless sensor networks (WSNs). The sensor nodes are usually battery operated hence energy remains the biggest constraint for WSNs. This is the very reason why energy conservation has always been one of the foremost priorities while designing WSNs. Due to the hardware and software limitations sensor networks require energy efficient and power-aware protocols. In this work we discuss an adaptive frame size algorithm proposed for the MAC layer in order to improve energy efficiency thereby increasing the network lifetime. The new MAC uses a variable frame size, which is adjusted depending on the wireless channel quality. The MAC uses a new correction and prediction technique called an Extended Kalman Filter.(EKF) to compute an optimal frame size for data transmissions. Using a variable frame size not only conserves energy, but also keeps system degradation caused by the time varying and bursty wireless channel to a minimum. We designed and implemented the enhanced MAC layer on sensor Motes to evaluate our approach. The energy measurements were taken directly from the sensor nodes. The results showed an improvement in energy efficiency of up to 5 % for 3 nodes and it is anticipated that the energy efficiency will be higher for larger networks.