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.
