TDMA scheduling of group aware tree in Wireless Sensor Networks

Data collection is an important operation in Wireless Sensor Networks. Sensors are deployed in given region of interest. They sense physical phenomenon and transfer data to a central node known as Sink. Tree is a widely used routing topology and Time Division Multiple Access (TDMA) is a widely used Medium Access Control (MAC) protocol. Sink is at the root of the tree. Often nodes in a tree aggregate the data coming from children with their own data. Data aggregation results in energy conservation and reduction in network traffic. Often sensor networks are heterogeneous in nature. Multiple groups (or types) of sensors are deployed in given region. In heterogeneous network, tree formation should consider presence of different groups. That is, a node should select node of same group as itself as parent. This is known as group aware tree formation. Other approach is static tree formation. In static tree formation, parent is selected without considering its group. Group aware tree formation increases chances of aggregation. Inspired from work done in [9] and [10], we have implemented group aware tree formation .Group aware tree formation is followed by TDMA scheduling of edges. Performance measures like energy consumption and number of time-slots used are examined. It is concluded that group aware tree formation results in less number of required timeslots compared to static tree and energy consumption is also less.