TTMA: Traffic-adaptive Time-division Multiple Access Protocol Wireless Sensor Networks

Duty cycle mode in WSN improves energy-efficiency, but also introduces packet delivery latency. Several duty-cycle based MAC schemes have been proposed to reduce latency, but throughput is limited by duty-cycled scheduling performance. In this paper, a Traffic-adaptive Time-division Multiple Access (TTMA), a distributed TDMA-based MAC protocol is introduced to improves the throughput by traffic-adaptive time-slot scheduling that increases the channel utilisation efficiency. The proposed time-slot scheduling method first avoids time-slots assigned to nodes with no traffic through fast traffic notification. It then achieves better channel utilisation among nodes having traffic through an ordered schedule negotiation scheme. By decomposing traffic notification and data transmission scheduling into two phases leads each phase to be simple and efficient. The performance evaluation shows that the two-phase design significantly improves the throughput and outperforms the time division multiple access (TDMA) control with slot stealing.