A Hybrid MAC Protocol for Different Densities of Clusters in Wireless Sensor Networks

Abstract

To Design the medium access protocol for cluster based sensor networks is a critical one. The information transfer within the cluster will follow CSMA, TDMA, FDMA or some hybrid approaches. Several collision reduction approaches has been discussed earlier. At the deployment phase the motes are airdropped sometime, afterwards these sensors are combined together and form the network as per the application requirement. In many applications, sensor nodes are deployed randomly over the entire desired area. In this way, the sensing areas of different nodes may partially overlap. During the cluster formation after deployment the clusters of the network may have different densities (i.e. no. of nodes in the clusters is not same). In this situation affording the default medium access will not advisable one.  In order to address the problem, in this paper a hybrid medium access protocol (HMDD) has been developed. The proposed protocol identifies the size of the cluster initially and suggests the medium access scheme according to that.