Stable Route AODV Routing Protocol for Mobile Wireless Sensor Networks

Wireless Sensor Networks (WSN) are widely used for various applications such as habitat monitoring, structural health monitoring, logistics, patient monitoring etc. Mobility of nodes in these applications are different. Generally usual MANET based routing protocols are adapted for these type of WSNs. AODV is one of the most commonly used routing protocol for both MANETs and WSNs. But in WSNs, when the mobility is high, AODV needs to find new paths to the destination frequently as the already established links breaks because of node movement. The proposed method aims at enhancing the traditional AODV protocol in such WSN applications by building a stable route during the route discovery phase, thus avoiding link breaks that happen due to node movement. This method uses Received Signal Strength Indicator (RSSI) to determine the participation of a node in the route building process. To mitigate the effects of RSSI variations due to environment, an Exponential Moving Average filter is used to smooth out the RSSI variations. If this RSSI value is less than a threshold, the node is not selected to be part of the active route. Lesser RSSI indicates longer distance between the nodes and more chances of link breakage. A neighbor node with the highest RSSI, that meets the threshold criteria, is selected to be the next forwarding node, thereby avoiding link break and ensuring stability of the active route between the source node and the destination node. This would in turn, reduce the energy consumed in the network and hence increase the network lifetime of the WSN. To conclude the effectiveness of the proposed scheme, the simulations are carried out in a WSN scenario and the results are analyzed in comparison with the traditional AODV protocol. Network Simulator, NS2 is used to carry out the simulation.