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Languages : en
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Book Description
A mobile ad hoc network is a collection of autonomous nodes connected to each other in a peer-to-peer fashion on a wireless medium. Such networks are used in emerging applications which require co-operative mobile data exchange in areas where there is little or no infrastructure available or where providing such infrastructure is not cost effective. Efficient dynamic routing is a major research challenge in such a network. Multipath routing provides a strong potential for efficient routing by maintaining multiple routes. This provides some form of fault-tolerance, as alternate paths can be used when one breaks. Also, data packets can be forwarded via multiple paths concurrently thus exploiting a larger network capacity. However, CSMA (carrier-sense multiple access) being a dominant form of channel access protocol in mobile ad hoc network, multipath forwarding is often unable to exploit its full potential. This is because multiple paths may form in each others2 radio neighborhood limiting spatial diversity. Data transmission in one path causes sufficient interference in another such that only one path can be used at a time. This phenomenon has been known as 3route coupling.4 We investigate the use of multichannel CSMA-based medium access protocols to reduce the impact of such route coupling. We use two such multichannel protocols to demonstrate that a significant throughput improvement is possible at high offered loads relative to the single channel CSMA for multipath data forwarding scenarios. One of the protocols chooses the channel based on interference power measurement at the sender. The other chooses a unique channel for each path. Our study shows that the multichannel protocols are able to limit the impact of interference between neighboring transmissions effectively.
