18-12-2009, 09:02 PM
Adaptive Routing in Adhoc Networks.pdf (Size: 2.05 MB / Downloads: 193)
ABSTRACT
The dynamics of an ad hoc network are a challenge to protocol design because mobility inevitably leads to unstable routing, and consequently flows encounter fluctuations in resource availability on various paths during the lifetime of a session. This has become serious, especially for those protocols based on single-path reservation, as frequent reservation and restoration of reservation-based flows increase the instability of connections. Advances in wireless research are focusing more and more on the adaptation capability of routing protocols due to the interrelationship among various performance measures such as those related to topological changes (link breakages, node mobility, etc.) and quality of service (QoS) parameters (load, delay, etc). After giving a more detailed discussion of the existing work in adaptive routing, we propose a new routing protocol for adhoc wireless networks - Multipath Source Routing (MSR), which is an extension of DSR(Dynamic Source Routing) that incorporates the multipath mechanism into DSR. Based on the measurement of RTT(Round Trip Time), we propose a scheme to distribute load among multiple paths. MSR is an adaptive routing for ad hoc networks. It considers the two fundamental issues in its design. MSR may adapt to topology changes by retaining the route discovery and route maintenance mechanism of DSR. In addition, MSR employs a probing-based load-balancing mechanism. Simulation results show that MSR can improve the packet delivery ratio and the throughput of TCP and UDP, and it reduces the end-to-end delay and the average queue size while adding little overhead. As a result, MSR decreases network congestion and increases the path fault tolerance quite well.