A MAC Protocol Based on S-MAC for Power Asymmetric WSN Network

The communications are interrupted by the hidden terminals in the traditional MAC protocols when the nodes¿ power is asymmetric in WSN networks. On the basis of S-MAC the improved protocol is proposed. Node judges whether the power asymmetric nodes are occurred in the vicinity of it according to the link state with neighborhood nodes. Then neighborhood nodes broadcast bandwidth reservation (BRES) message intelligently after overhearing CTS. After receiving BRES the high power nodes will inhibit their own transmissions for the duration. So the improved protocol avoids the interruption of hidden terminals, reduces the collisions, decreases the delay and increases throughput. The simulation proves the performance of improved protocol is better than S-MAC in power asymmetric WSN networks.