Design of novel node distribution strategies in corona-based wireless sensor networks

Considering coverage, efficiency, and durability, three nonuniform node distribution strategies for a corona-based wireless sensor network (WSN) are proposed in this paper. To derive lower bounds on sensor nodes in coronas, we investigate the optimal node placement based on coverage. We then prove the feasibility of balanced energy depletion for a primitive geometric node distribution (GND) and a primitive energy proportional node distribution (EPND). Applying the optimal node placement and GND enables us to propose the first strategy (Strategy I) to reach completely balanced energy depletion. Combining the optimal node placement, EPND, and a simple switch scheduling, the second strategy (Strategy II) and the third strategy (Strategy III) are designed for a uniform-width corona model and a nonuniform-width corona model, respectively. Although balanced energy depletion may not be reached, Strategy II achieves the longest network lifetime and Strategy III requires the fewest sensor nodes among the three strategies. Finally, the performance investigation done by both analytical and simulation approaches exhibits the superiorities of the proposed strategies over the two closest strategies in the literature in terms of number of sensor nodes, network lifetime, and residual energy.