Wireless sensor networks consist of a large number of tiny sensors that have only limited energy supply. One of the major 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 redundant sensors. In this paper, the problem of estimating redundant sensing areas among neighbouring wireless sensors is analysed. We present an interesting observation concerning the minimum and maximum number of neighbours that are required to provide complete redundancy and introduce simple methods to estimate the degree of redundancy without 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 redundancy. With random sensor deployment, our analysis shows that partial redundancy is more realistic for real applications, 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 designing effective sensor scheduling algorithms to reduce energy consumption and in the mean time maintain a reasonable sensing area.
A theoretical analysis of the problem of estimating redundant sensing areas among neighboring sensors shows that partial redundancy is more realistic for real applications as complete redundancy is expensive REF .
Analysis on the redundancy of wireless sensor networks
WSNA '03
Computer Science