# Review Report on a Heuristic Routing Protocol for Wireless Sensor Networks in Home Automation (Wsnha)

Pages: 3 (1043 words) Published: April 13, 2013
Review Report on A Heuristic Routing Protocol for Wireless Sensor Networks in Home Automation (WSNHA) Proposed by Xiao Hui Li, Seung Ho Hong and Kang Ling Fang This review report summarizes the proposed concept of WSNHA greedy-algorithm heuristic routing(GAHR) protocol by using the Greedy algorithm and A* heuristic path finding to find a optimal route from source to destination while simultaneously records the changes in network topology. WSNHA-GAHR protocol aims to address the challenge of when implementing WSNHA -- high energy efficiency, low storage and simple algorithm, high dependency of sensor node distribution and self adaptation to network topology changes The Greedy algorithm is a simple approach that finds the shortest and optimum route from the source to destination, based on the immediate information known by the node to its neighbours and forwards the packet to the neighbour closest to the destination. The decision make does not account to effects in future. The selection function is based on f = min (d1, d2,...,dN), where di is the distance between ith neighbour of X and the destination for i ϵ [1,N]. To resolve infinite loop issue caused by Greedy algorithm, the WSNHA-GAHR protocol uses the A*route finding algorithm, a distance-plus-cost function [h(x) = d(x) + c(x)] to find the least-cost path from a given initial node to the destination node taking account the distance already traveled. d(x) is the path cost function and c(x) is an admissible heuristic estimate of the distance to destination. The main idea of the Algorithm is that a node,S chooses the smallest heuristic value of its neighbours as its next hop (example n1), set and broadcast a new heuristic value[h(S) = dsn1 + h(n1)] to its neighbours. When packet is forwarded to n1 from S, n1 finds its neighbours in the similar way. Each node maintains three tables: Ntable (records neighbours' coordinates of the local node), Htable (records heuristic value between local node and the destination...