Comparison of optimum density of sensor nodes required for desired coverage in a realistic scenario using sensing models

One of the critical quality of service (QoS) parameter that needs consideration in any wireless sensor network (WSN) design is network area coverage which signifies the efficiency with which the network area can be covered by the deployed network. Node sensing models are used to predict the coverage fraction percentage for a given number of sensor nodes in a predetermined network area. Alternatively, a more practical approach is to compute the optimum density of sensor nodes to be deployed such that they can satisfy temporal and spatial requirement within a given economical constraint. In this paper, these node sensing models are revisited to investigate the optimum density of randomly deployed sensor nodes required to attain the desired network area coverage. This investigation can be used to estimate the number of sensor nodes to be deployed in a network area of any given size. The effect of the sensing device characteristics and environmental parameters on the density of sensor nodes is also analyzed to emphasize the fact that these parameters need due consideration in a realistic scenario. This comparative study based on node sensing models can be taken up as a starting point to design and evaluate an effective WSN so as to match the proposed model to a real world scenario.

I. Introduction

In today's world, WSN have become a promising technology to cater to successful implementation of diverse applications ranging from environmental monitoring to mission critical ones. WSN is made up of a many low powered sensor nodes that are spatially distributed in a network. These sensor nodes operate in an autonomous manner and have limited communication, computation and sensing capabilities [1]. A number of investigations related to QoS parameters of paramount importance like energy efficiency, reliability and latency exist in literature. These researches assume that a sufficiently large number of sensor nodes are deployed. Instead, as a starting point in any WSN design, there is a need to compute the optimum density of sensor nodes to be deployed in the network area such that these sensor nodes collectively can satisfy temporal and spatial coverage requirement, or alternatively provide maximum sensing coverage in a given economical constraint. Deployment of an insufficient number of sensor nodes may lead to failure of the very purpose of the application, whereas over deployment will lead to higher system cost.