A hybrid MAC protocol for wireless sensor networks

Energy efficiency is an important issue for wireless sensor networks (WSNs). A MAC protocol for WSNs may tolerate higher packet latency in order for minimizing energy consumption, but such a MAC protocol may not accommodate real-time applications. In this paper, we present a hybrid MAC protocol that minimizes both energy consumption and packet latency simultaneously. The protocol utilizes a cross-layer approach that dynamically switches the MAC behavior between TDMA and CSMA based on the routing information of AODV. The nodes which are not involved in data transmission are kept in TDMA mode to minimize their energy consumption. When a node receives a routing request message, it switches to CSMA mode for receiving subsequent data packets promptly. We evaluate the performance of our protocol with various network density. The simulation results show that our protocol can improve both energy efficiency and packet latency of WSNs.