TDMA Scheduling Algorithm Using Independent Sets in Network Graph

Wireless Sensor Networks (WSNs) is a distributed wireless network consists oflarge amount of sensor nodes which gather useful information from a variety of environment andthese sensor nodes communicate with each other in a multi-hop radio networks, with the endgoal of handing their processed data to the data collector or access point (AP) [1,2]. WSNs havemany issues such as self-configuration, fault-tolerance, adaptation, flexibility, energy efficiency,security, scalability, interference, architectural issues, mobility and delay tolerance [3]. Amongthese issues the most critical issue is to save energy and interference. The aim of this study is toconstruct the network graph which is conflict free and has minimum interference and minimumenergy consumption. We have MAC Access protocols but TDMA protocol is more efficient thanother protocols because TDMA can eliminate collisions and remove the need for a back-off [4].A TDMA scheduling algorithm is constructed for the wireless sensor network, which is based onthe creation of separate independent sets of the representing network graph. Independent sets areemployed to minimize the time slots needed for the complete transmission of data packets in thenetwork. An algorithm has been developed to implement it and there are three different steps inthe implementation of this algorithm. In first phase, the minimum independent sets of thenetwork are constructed. In second phase, the conflict graph of given network graph has beencreated. In third phase, time slots are assigned to all the transmissions according to theindependent sets which were created in first phase, so that all the data packets are transmitted tothe access point (AP) or data collector. The simulation results indicate that the TDMAscheduling algorithm reduce the interference and energy consumption in the network graph.