Energy aware geographical routing and topology control to improve network lifetime in wireless sensor networks

Sensor networks comprise large number of sensor nodes densely located in an area for sensing purposes. A key consideration in sensor networks is that the sensor nodes have limited battery resources that determine the lifetime of the network. Motivated by the fact that geographical routing is localized, scalable and nearly-stateless, we propose three energy-aware geographical forwarding schemes. The aim is to improve the network lifetime by considering the residual energy of neighbours in deciding the next-hop while preserving the localized, scalable and nearly-stateless property of geographical routing. In view of a possible heavy traffic along the perimeter of the hole, which may cause nodes along this perimeter to die faster, a hole avoidance method is proposed to reduce the traffic along the hole to remove this possibility. Topology control algorithm is proposed to be executed at each node to remove undesirable geographical neighbours determined by a link cost. It removes geographical neighbours without causing unnecessary holes and still maintains the connectivity in the network. The main aim of removing undesirable geographical neighbours is to achieve the global objective of having a longer network lifetime. The effectiveness of the three proposed forwarding schemes and the topology control algorithm are verified through extensive simulation results