Multi-Channel Mobile Ad-Hoc Links for Multimedia Communications
This paper is mainly concerned with multi-channel transmission of real-time information such as video over multi-hop ad-hoc links. We propose two multi-channel routing protocols. The first is based on single-path routing and aims at suppressing the intra-path interference in a CSMA/CA network. This is achieved by developing a link-partitioning scheme where nodes in the neighboring partitions operate at different non-overlapping frequency bands. For this approach we present a systematic channel assignment technique, which has been specifically developed for the Ad-hoc on-demand distance vector (AODV) routing protocol. It is shown that this partitioning scheme can considerably enhance the throughput performance of a multi-hop link. The second multi-channel scheme is developed for transmission of real-time traffic over multiple-path routes. Bear in mind that multiple-path diversity routing has been shown to be very effective in dealing with network congestion in wire-line IP networks. Unfortunately, in mobile ad-hoc network environments, particularly for real-time traffic, this approach can suffer greatly from co-channel interference due to the simultaneous transmission of packets via multiple routes. In this respect, we have designed a dual-path routing protocol, which guarantees a different frequency band for each path, thus eliminating any inter-path interference. We show that this protocol has an important property, which is reducing the probability of losing both routes at the same time. Based on this important property, we demonstrate that a combination of the routing protocol and dual description video coding can greatly enhance the ad-hoc network performance of video transmission for real-time traffic.