Effective lifetime-aware routing in wireless sensor networks

Lifetime-aware routing and desired sensing spatial coverage (SSC) are two main challenges ahead of an ad-hoc, sensor-based, battery operated monitoring system known as wireless sensor network (WSN). Depending on the application, a necessary SSC level is essential to comply with the needed surveillance quality. On the other hand, network lifetime is of a major concern due to limited energy available to each sensor node. Formerly proposed lifetime-aware routing algorithms have usually defined lifetime as the duration before the first node runs out of energy. This criterion is not consistent with real-world WSN, where a number of sensors are likely to die due to hardware failures, natural impacts, etc. Initially, we propose a method that determines the network resource specifications, i.e., the number of available nodes and their sensing range, according to the required SSC and the necessary confidence level. Later on, a novel lifetime criterion which considers the SSC as the WSN effective operation criterion is introduced. Afterward, the new criterion is embedded into the flow augmentation algorithm and the normalized network lifetime is calculated for several scenarios using the solutions of the corresponding linear programming equations. Simulation results show significant improvement achieved in the lifetime. It is also shown that this new method is considerably more robust to the routing algorithm parameters compared to the performance achieved by the published Flow Augmentation algorithm.