Improving reliability and efficiency of communications in WSNs under high traffic demand

Abstract

Carrier Sense Multiple Access protocols are the most widely used methods for collision avoidance in Wireless Sensor Networks (WSNs). These protocols are prone to suffer from the hidden and exposed terminal problems, which lead to inefficiency and unfairness in the communications. Both problems are particularly significant in applications with massive traffic requirements, commonly found in WSNs. The control procedures generally employed to alleviate these effects may lead to performance degradation in the presence of intensive communications. In this paper, we propose a CSMA protocol based on the physical interference model, which mitigates the effect of hidden and exposed terminal problems in a real testbed. Our protocol provides to each pair of transmitter-receiver nodes a different threshold, which determines the maximum tolerated noise for this transmission. No additional control method is used to avoid collisions. Finally, we measure the performance of our protocol by executing over it the average consensus algorithm, which determines the high traffic demand. The packet reception rate, the throughput and the convergence of the consensus algorithm are evaluated in a real testbed.