Localization is an important challenge in wireless sensor networks (WSN). Localization usually refers to the process of dynamically determining the position(s) of one or more node(s) in a larger network. The challenge lies in efficiently providing acceptable accuracy while conforming to the many constraints of WSNs and at the same time handling scalability.
Wireless Sensor Networks have been proposed for several 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 point to point distance estimates. Localization of sensor nodes is the foundation of the entire wireless sensor network. 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.
This thesis introduces the localization process of sensor nodes based on Distance ？ Vector Hop (DV-HOP) algorithm. Based on this, it proposes an improved DV-HOP algorithm which is based on coefficient least square method. The new algorithm called Coefficient Allocated DV-Hop (CA DV-Hop) reduces node？s location error by awarding a credit value with respect to number of hops of each anchor to an unknown node to differentiate the anchor node influence, and proposed a new method of determining location of the node. The simulation results show that the proposed improvements can greatly enhance the localization accuracy of the nodes.
