Analysis on the redundancy of wireless sensor networks
Yong Gao, Kui Wu, Fulu Li · 2003
Wireless sensor networks consist of a large number of tiny sensors that have only limited energy supply. One of the ma-jor challenges in constructing such networks is to maintain long network lifetime as well as sufficient sensing area. To achieve this goal, a broadly-used method is to turn off redun-dant sensors. In this paper, the problem of estimating re-dundant sensing areas among neighbouring wireless sensors is analysed. We present an interesting observation concern-ing the minimum and maximum number of neighbours that are required to provide complete redundancy and introduce simple methods to estimate the degree of redundancy with-out the knowledge of location or directional information. We also provide tight upper and lower bounds on the probability of complete redundancy and on the average partial redun-dancy. With random sensor deployment, our analysis shows that partial redundancy is more realistic for real applica-tions, as complete redundancy is expensive, requiring up to 11 neighbouring sensors to provide a 90 percent chance of complete redundancy. Our results can be utilised in design-ing effective sensor scheduling algorithms to reduce energy consumption and in the mean time maintain a reasonable sensing area.