Contention Window Prioritization for Heterogeneous Traffic in Wireless Sensor Networks

Abstract

Dealing with heterogeneous traffic has become a major MAC layer challenge for the Wireless Sensor Networks (WSN) due to emerging applications. Most of the times, the service requirements for WSN applications differ based on the traffic type or priority. Among many other schemes, prioritization of Contention Window (CW) has been proposed in the past which offers advantage to the traffic of high priority. This research aims at analyzing the influence of prioritized CW scheme for the basic Carrier Sense Multiple Access (CSMA) protocol, frequently deployed for the contention based channels. The performance of CSMA with prioritized CW while dealing with heterogeneous traffic has been compared against the basic CSMA. Two types of traffics have been used to illustrate heterogeneous traffic and evaluate the proposed scheme. Performance metrics of throughput and average delay have been investigated in order to validate the advantage of using prioritized CW partitioning. The scheme has been implemented using Tiny-OS source code developed for the Mica2 platform. Avrora emulator has been used for conducting experiments. results have revealed a positive impact of using CSMA with prioritized CW on the network performance as compared to the basic CSMA.