DISTRIBUTED ENERGY-EFFICIENT ALGORITHMS FOR COVERAGE PROBLEM IN ADJUSTABLE SENSING RANGES WIRELESS SENSOR NETWORKS

Abstract

Due to wide range of applications of Wireless Sensor Network (WSN), lots of effort has been dedicated to solve its various issues. Among those issues, coverage is one of the most fundamental ones of which a WSN has to watch over the environment such as a forest (area coverage) or set of subjects such as collection of precious renaissance paintings (target of point coverage) and collect environment parameters and maybe, further monitor the environment. With variable sensing range, the difficulties to cover a continuous space (where number of points is infinity) in the area coverage problem becomes somewhat harder than covering limited number of discrete points in the target coverage problem. Very few papers have paid effort for the former problem. In this paper, we consider the area coverage problem for WSN where sensors can arbitrarily change their sensing ranges under some upper bound. We first improve the work in [1] so that the boundary effect is ruled out and the monitored area can be completely covered at all cases. Next, we extend that improved algorithm by introducing two distributed scheduling algorithms which are trade-off in term of network lifetime and algorithms efficiency. The major objective of each of our 3 proposed algorithms in this paper is to balance energy consumption and to maximize network lifetime. Our proposed algorithm efficiency is shown by algorithms complexity analysis and extensive simulation. In compared with the work in [1], our proposed algorithms are not only better in providing coverage quality, they could also greatly lengthen network lifetime and greatly reduce the unnecessary coverage redundancy.