Congestion Controlled d-Adapt-OR for Adhoc Networks

Abstract

Opportunistic routing scheme is used to route data packet from source to destination. Broadcasting nature of the wireless networks is utilized here to send data packets. A suitable forwarder node is selected from the neighboring node based on the rank ordering of the nodes. The nodes are ranked according to a score called Estimated Best Score (EBS). This score is calculated by considering the network congestion which is one of the major problems in adhoc networks. Probability of unsuccessful delivery of the packet become very less. Different types of packets are used to communicate between different nodes. A distributed and asynchronous routing scheme is introduced to route the packet. The proposed routing scheme doesn't require any initial knowledge about the network topology. Another problem with adhoc wireless networks is the presence of selfish nodes. For the successful delivery of the packet at the destination we have to avoid the presence of selfish nodes in the networks. So each node calculate the selfishness of its neighboring nodes. The data packet is forwarded by considering the selfishness of the node. I. Introduction Wireless adhoc networks are decentralized type of networks. A node in wireless adhoc networks communicate with the node which is in the range of the node. Wireless adhoc networks are considered in this work. Routing in adhoc networks is very important in order to communicate with the node which is not directly reachable. Different conventional routing scheme is now used to direct packet from source to destination. But most of them is not deal with the network congestion. They always result in unnecessary packet retransmission. Conventional routing scheme always find a fixed path along source to destination. So it always requires maintaining the knowledge about the network topology and statistics to find a path. Here a routing scheme called opportunistic routing is used. Opportunistic routing scheme doesn't require any previous knowledge about the networks and statistics. It dynamically route the packet from source to destination without any initial knowledge about the networks. This routing scheme exploits the broadcast nature and the opportunities available in the networks. It selects a node from its neighbors as next relay node based on some conditions. According to these conditions order the neighboring nodes and select one node as the relay node. And this process continues until it reaches the destination. The selection of next relay node may based on some geographical location or shortest path etc. Here proposed a routing framework called d-Adapt-OR that is distributed adaptive, asynchronous opportunistic routing scheme to route the packet. This routing scheme has low complexity and low overhead. While routing the routing scheme considered the congestion in the network and finds a path with less congestion. And it assumes no knowledge about network topology. One of the major problems in wireless adhoc networks is the presence of selfish nodes. A node is said to be selfish if it doesn't provides its own resources to forward others packet. But it takes the advantage of other node's resources and memory to forward its own packets. The nodes that drop the packet without forwarding it is a selfish node. A node may selfish even if it doing some other tasks at the packet arrival time. So the presence of selfish nodes reduces the packet success probability and deteriorates the performance of the network. So we have to avoid this type of nodes from the networks for improving the probability of successful delivery of the packet.