Signal Strength Based Congestion Control in In MANET

All nodes in MANET (Mobile Ad-hoc Network) are mobile and dynamically connected in an arbitrary manner.  Mobility causes frequent link failure which results in packet losses. TCP assumes that these packet losses are due to congestion only. This wrong assumption requires packet retransmissions till packet arrives successfully at the receiver. Goal is to improve TCP performance by using signal strength based cross layer approach which obviously resolves the congestion. We are reviewing a signal strength based measurements to improve such packet losses and no need to retransmit packets. Node based and link based signal strength can be measured. If a link fails due to mobility, then signal strength measurement provides temporary higher transmission power to keep link alive. When a route is likely to fail due to weak signal strength of a node, it will find alternate path. consequently avoids congestion. We will make changes at MAC routing and routing layer to predict link failure. MANET hits the protocol's strength due to its highly dynamic features, thus in testing a protocol suitable for MANET implementation we have selected two routing protocols AODV and DSR. Packet Delivery Ratio, Packet Drop, Throughput and end to end delay are the metrics used for performance analysis of the AODV routing protocols. Keywords: Congestion  control, Signal strength, TCP performance ,Cross layer interaction, Route discover

A Study of Congestion Aware Adaptive Routing Protocols in MANET

Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in last few years. Much of this work is targeted at finding a feasible route from a source to a destination without considering current network traffic or application requirements. Routing may let a congestion happen which is detected by congestion control, but dealing with congestion in reactive manner results in longer delay, and unnecessary packet loss and requires significant overhead if a new route is needed. Routing should not be aware of, but also be adaptive to, network congestion. Adaptation to the congestion helps to increase both the effectiveness and efficiency of routing. These problems are solved by the congestion-aware routing protocols in certain degree. These protocols which are adaptive to congestion status of mobile ad-hoc network can greatly improve the network performance. In this paper, we present the survey of congestion adaptive routing protocols for mobile ad-hoc network. Finally, the future direction of congestion-aware routing protocols is described. Keywords: Ad hoc networks, congestion aware routing, Congestion metric, congestion adaptabilit