An Event Driven TDMA Protocol for Wireless Sensor Networks

MAC protocol is the major consumer of sensor energy because it controls the activity of wireless radio of sensor nodes directly. The energy efficiency of MAC protocol makes a strong impact on the network performance. TDMA-based MAC protocol is inherently collision free, and can rule out idle listening since nodes know when to transmit. But traditional TDMA protocol is not suitable for event driven application. In this paper, we present ED-TDMA, an event driven TDMA protocol for wireless sensor network. It improves channel utility by changing the length of TDMA frame according to the number of source nodes and saves energy with bitmap-assisted TDMA schedule. In addition, ED-TDMA employs intra-cluster coverage to prolong network lifetime and to improve system scalability. Simulation results show that ED-TDMA performs better than some other MAC protocol for event driven application in wireless sensor network with high-density deployment and under low traffic.