On handling weakened topologies of Wireless Sensor Networks

The deployment of wireless sensor networks (WSNs) is expected to have a significant impact on the efficiency of many civil and military applications, such as disaster management, environment monitoring, combat field surveillance and space exploration. In unattended WSN setups, most of the energy aware routing approaches pursue multi-hop paths in order to minimize the total transmission power. However, the hops close to the base-station (also known as the sink) become heavily involved in packets receiving and forwarding and thus their batteries get depleted rather quickly, and sometimes become traffic bottlenecks. The failure of these nodes also can create a void around the sink and significantly increase the energy consumed in communication with the sink. This paper evaluates the effectiveness of three approaches for handling the weakened network topology caused by the failure of sensors around the sink. The approaches are: (1) increasing the population of sensors in selected areas; (2) increasing the number of sink nodes in the network; and (3) repositioning the existing sink. The performance of the three approaches is validated in a simulated environment.