An energy-efficient and reliable MAC for sensor network

In this paper, a TDMA-based medium access control protocol (GMAC) for wireless sensor networks is proposed. We use global time synchronization and data gathering tree as the foundation of the protocol to form a contention free network for applications that sensors periodically send packets to the sink. To assign time-slots and frequency channels for nodes, a distributed resource allocation strategy is designed. Furthermore, a MAC scheme is proposed to improve packet delivery reliability in the protocol. The simulations show that the protocol can reduce energy power consumption in a heavy load network than contention-based protocols and achieve higher reliability in the periodically report applications.