Adaptive and Distributed TDMA Scheduling Protocol for Wireless Sensor Networks

The Wireless Sensor Networks are used to monitor physical or environmental conditions in different environments. The main challenge in collecting data in these networks is adopting a TDMA mac protocol to allocate time slots to nodes that considers the minimum power consumption and delay. We propose an adaptive and distributed TDMA scheduling protocol for slot assignment in wireless sensor network called AD-TDMA. The AD-TDMA mac protocol saves energy by offering a suitable awake-sleep state scheduling for nodes and applies depth-first-search to send node data in network as routing path. AD-TDMA provides a reduced end-to-end delay by minimizing buffering and reusing of time slots by nodes which are outside each other’s interference range. In AD-TDMA, the TDMA scheduling schema is created by nodes distributedly. Every node in its lifetime updates its scheduling distributedly according to the exist conditions in network. Hence, the proposed protocol is stable against the faulty nodes and dynamic changes in network topology. The AD-TDMA mac protocol is useful for both periodic and event-driven data gathering in wireless sensor networks. The performance of AD-TDMA has been evaluated by simulating in J-Sim simulator and the results show a significant reduction in end-to-end delay and energy saving in sensor nodes.