Energy-hole avoidance and lifetime enhancement of a WSN through load factor

In wireless sensor networks, nonuniform communication load across a network often leads to the problem of energy holes or hot spots, i.e. nodes nearer high activity regions deplete their energy much faster than nodes elsewhere. This may partition the network into unreachable segments and thus adversely affect network lifetime. The problem is more acute in random and sparsely deployed networks. Therefore, we propose a deployment strategy that, using the least possible nodes, prolongs network lifetime by avoiding energy holes and also ensures full sensing and communication coverage. The scheme handles the energy imbalance by selecting an appropriate set of communication and sensing ranges for each node based on effective load on that node. After adjusting these ranges, nodes are strategically placed at locations where their energy drains uniformly and thus network lifetime is prolonged. The approach is verified analytically and validated through ns-2 based simulation experiments. The results reveal significant improvements over existing schemes.