Improvement And Realization Of AODV In Wireless Sensor Networks

A wireless sensor networks is a special Ad Hoc wireless network; through the Ad Hoc network technology scattered sensors form a network to achieve communications with the control center. Because of the constraints of sensor nodes energy, transmitting power and the limited coverage of nodes, when a node needs to communicate with nodes out of its coverage, it will need middle nodes to forward packets, which is called multi-hop. The use of multi-hop routing reduces the transmission power of a single node, saves energy and extends working time. Therefore, the realization of multi-hop routing communications is very necessary to WSNs that pursues low power consumption.Routing technology is the key to the wireless sensor networks technology, and it is also one of the important factors affecting the overall network performance. The topology structure of Ad Hoc network changed dynamically, any two nodes can communicate. WSNs and the Ad Hoc networks are very similar, but WSNs have their own characteristics. WSNs are a quasi-static topology and adopt many-to-one communication mode. So the existing Ad Hoc Networks Routing Protocol does not completely apply to wireless sensor networks. Ad Hoc On-Demand Distance Vector is a typical Ad Hoc Network Routing Protocol. Ad Hoc network routing protocols suit to mobile environment and do not consider the restriction of energy. It uses the latest and shortest path as routing metric, and the routing table only maintains one piece of routing information for a given destination node. In consideration of the fact that nodes in WSNs are almost immobile, this thesis uses the framework of AODV routing protocol, simplifies the message type of AODV, and presents an improved routing algorithm-WAODV. WAODV algorithm records more than one routing information message in the node routing table. When a routing fails it does not need to initiate the re-routing request, reducing the number of messages.The thesis describes the working process of AODV, analyzes the theory of AODV routing protocol, then puts forward and achieve the WAODV algorithm. On the actual hardware platform MicaZ node, WAODV algorithm is run to demonstrate the feasibility of WAODV in wireless sensor networks. Through comparing AODV that is based on the measure of the minimum hops with WAODV that is based on the measure of value of RSSI (received signal strength indicator), the analysis result indicate that the improved algorithm WAODV have made the whole networks have long life circle at a relatively low energy consumption level, and also have improved reliability of data transmission.