Abstract:In a multi-hop wireless sensor network (WSN), sensor nodes closer to the sink have to take a heavier traffic load, and thus, these sensor nodes tend to deplete their energy faster. This uneven energy depletion leads to what is called an energy hole around the sink. If this happens, no more data can be delivered to the sink, and a considerable amount of energy is wasted. This paper investigates the energy hole problem in WSNs. Based on the analysis of traffic load distribution in the continuous space of the network, a load-similar node distribution strategy is proposed to balance energy consumption and solve the energy hole problem. Sensor nodes are deployed according to the load distribution. Most nodes will be deployed in the range where the average load is higher. The impact of idle listening is also investigated. Simulation results demonstrate that the load-similar node distribution strategy prolongs a longer network lifetime than existing nonuniform node distribution and uniform node distribution strategies that do not take in consideration idle listening. When idle listening is considered, the energy consumed on idle listening plays an important part in the overall energy consumption and impacts the network lifetime. The load-similar node distribution improves the network lifetime, although the improvement is not as prominent as without considering idle listening. The analysis model and the proposed load-similar node distribution strategy have the potential to be applied to other multi-hop WSN structures.