Multi-Rate Support for Network-Wide Broadcasting in Manets

Abstract

Mobile ad-hoc networks (MANETs) utilize broadcast channels, where wireless transmissions occur from one user to many others. In a broadcast channel the same transmission can lead to different information rates to different users depending on the channel capacity between the transmitter and receiver pair. According to coding theory, there is a certain channel capacity that limits the rate of information that can be sent through the channel. Thus, different channel capacities result in different acceptable rates for the users. In this paper, we utilize a superposed coding scheme in a MANET scenario to provide different rates for users with different channel capacities using a single broadcast transmission. We have created techniques to extend this multi-rate concept to network-wide broadcasting scenarios, providing the ability for nodes to appropriately trade-off delay vs. quality. We describe our approach and provide simulation results showing the benefits and limitations of superposed coding in network-wide broadcasting.