TATD-MAC: A Traffic-Adaptive Synchronous MAC Protocol for Wireless Sensor Networks

Duty cycling improves energy efficiency but also introduces significant end-to-end delivery delay in wireless sensor networks. Several schemes have been proposed to reduce the delay, but throughput is limited by the scheduling performance. TATD-MAC introduced in this paper improves the throughput by improving the channel utilization with a traffic-adaptive time slot scheduling method. The proposed traffic-adaptive time slot scheduling algorithm first avoids assigning time slots to nodes with no traffic through fast traffic notification. It then achieves high channel utilization among nodes of traffic with extremely low overhead through an ordered schedule negotiation scheme. The two-phase design by decomposing traffic notification and data transmission scheduling into two phases leads each phase to be simple and efficient. Performance evaluation shows that the more efficient scheduling performance gained by the twophase design significantly improves the throughput of current synchronous MAC protocols and even outperforms time division multiple access (TDMA) control with slot stealing.