Lifetime optimization using nonuniform deployment and heterogeneous sensors in wireless sensor networks

Abstract

Wireless sensor networks consist of a large number of sensor nodes deployed in a region of interest for monitoring purposes. As sensor nodes are battery powered devices, their operation time is limited. In a multi-hop sensor network with many-toone communication characteristics, the nearer a node is to the sink, the more energy it consumes. Therefore, the nodes closest to the sink deplete their batteries faster than the others. Moreover, the network lifetime is bounded by the lifetime of these nodes, since when they fail, other nodes will no longer be connected to the sink. Unbalanced energy consumption in the network can be compensated by deploying sensors non-uniformly and using heterogeneous battery capacity sensors. This paper investigates the bene ts of topologies which exploit nonuniformity and heterogeneity. In the rst part of the thesis, we study the possibility of using di erent battery capacity nodes in di erent regions of the network. In the second part of the thesis, we consider dense networks and study how the network lifetime is a ected by using di erent densities in di erent regions of the network. The thesis shows that heterogeneous network topologies o er e cient usage of the total network energy resources. This e ciency results in signi cantly longer network lifetimes with the same total cost when variable capacity sensors or variable densities are used.