Improving DSR protocol in MANET using power-aware passive clustering

Abstract

Mobile ad hoc network is infrastructure less wireless network designed to provide service where other networks are not available or not possible to construct. Nodes are capable of acting as both router and host. Some of the difficulties of this network are mobility, lack of central controller, frequent topology change. Nodes in Ad hoc networks mainly uses blind flooding to find route to destination that introduces too much control overhead. In the network that nodes are energy constrained, it is good to reduce control overhead in the network so that nodes can be parts of the network for long time. In our modified DSR routing protocol we have limited the number of control packets propagated in the network. To limit the number of control packets we have used passive clustering by adding energy and distance as an additional parameter. We have modified the previously used passive clustering technique and applied to our modified DSR routing protocols. When nodes in the network have clustered, each node is assigned one of the following states such as head, gateway and ordinary. After the cluster has formed only head and gateway nodes are able to forward route requests so that routing overhead is minimized. We have created clustering header, which consists of node ID, state and energy. Clustering header is appended to the route request prepared. Besides, clustering header is also appended to the data packet while actual data packet is forwarding towards the destination. When a node receives the route request, it extracts information from the clustering header and store in its own neighbor list and determine its state based on its neighbor information. At the time when it receives clustering information from its neighbor, it computes the distance between them to easily detect when the node becomes outside of its transmission range. We have implemented our proposed solution on NS2.35. To show how efficient our work is, we have used packet delivery ratio, routing overhead, throughput and average end-to end delay as a performance metrics. We have compared our modified DSR routing protocol with the existing DSR routing protocol based on the above-mentioned performance metrics and it has showed better performance.