A Global Time Synchronized MAC for Wireless 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 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 consumption and achieve higher reliability than contention-based protocols .