Research on the energy hole problem based on unequal cluster-radius for wireless sensor networks

Clustering provides an effective way for prolonging the lifetime of a wireless sensor network. When cluster heads cooperate with each other to forward their data to the base station via multi-hop communication, the cluster head closer to the base station are burdened with heavier relay traffic and trend to die much faster, leaving areas of the energy hole problem and causing network partition. To address the problem, we propose a theoretically analytical method for the energy consumption with different cluster-radius in clustering network. The main conclusions are presented as follows: (1) The expression of cluster-radius ττ is given while the network lifetime is maximal. (2) In clustering network, the lifetime is longer than the network with the data transmitted directly. (3) We propose a novel and simple strategy to avoid the energy hole problem for data gathering scheme. Employing an unequal cluster-radius and alternate between dormancy and work is the core idea. That is, the network lifetime depends on the node which has the maximal energy consumption. And it is not the same node in this circumstance. So the total energy consumption is less than the network which employing an optimum and fixed cluster-radius and it can achieve an obvious improvement on the network lifetime. The theoretical analysis and simulation results show that the strategy is very simple and it can effectively avoid the energy hole problem. Therefore, the conclusions can present a better design guideline for wireless sensor networks.