Range-free localization schemes for large scale sensor networks
Proceedings of the 9th annual international conference on Mobile computing and networking - MobiCom '03
Wireless Sensor Networks have been proposed for a multitude of location-dependent applications. For such systems, the cost and limitations of the hardware on sensing nodes prevent the use of range-based localization schemes that depend on absolute pointto-point distance estimates. Because coarse accuracy is sufficient for most sensor network applications, solutions in range-free localization are being pursued as a cost-effective alternative to more expensive range-based approaches. In this
... , we present APIT, a novel localization algorithm that is range-free. We show that our APIT scheme performs best when an irregular radio pattern and random node placement are considered, and low communication overhead is desired. We compare our work via extensive simulation, with three state-of-the-art range-free localization schemes to identify the preferable system configurations of each. In addition, we study the effect of location error on routing and tracking performance. We show that routing performance and tracking accuracy are not significantly affected by localization error when the error is less than 0.4 times the communication radio radius. -753-2/03/0009...$5.00. 81 provides insight into the effect of localization accuracy on application performance degradation and identifies bounds on the estimation error tolerated by applications. The remainder of the paper is organized as follows: Section 2 discusses previous work in localization for sensor networks. Section 3 describes APIT. Section 4 gives brief descriptions of three other state-of-the-art range-free protocols to which we compare our work. Section 5 describes our simulation. Section 6 follows with a detailed performance comparison of the four rangefree localization algorithms described. Section 7 further investigates the impact of localization error on various locationdependent applications and protocols such as routing and target tracking. Finally, we conclude in Section 8. STATE OF THE ART Many existing systems and protocols attempt to solve the problem of determining a node's location within its environment. The approaches taken to solve this localization problem differ in the assumptions that they make about their respective network and device capabilities. These include assumptions about device hardware, signal propagation models, timing and energy requirements, network makeup (homogeneous vs. heterogeneous), the nature of the environment (indoor vs. outdoor), node or beacon density, time synchronization of devices, communication costs, error requirements, and device mobility. In this section, we discuss prior work in localization with regard to these network characteristics, device restrictions, and application requirements. We divide our discussion into two subsections where we present both range-based and range-free solutions..