Tree-Based Multicast Meshes with Variable Density of Redundant Paths on Mobile Ad Hoc Networks

Abstract

This paper proposes an adaptive multicast scheme for mobile ad hoc networks, called tree-based mesh with k-hop redundant paths (TBM k ), in which path redundancy is controlled depending on the status of the network such as traffic and mobility. The proposed scheme constructs a multicast tree and adds some additional links/nodes to the multicast structure as needed to support redundancy. TBM k includes all k- or smaller-hop paths between tree nodes to provide alternative paths among the nodes. TBM k enables tradeoffs between multicast tree (TBM0) and flooding (TBM ∞ ) by providing variable density of redundant paths. When the network is unstable and node mobility is high, a large k is chosen to provide more robust delivery of multicast packets; otherwise, a small k is chosen to reduce the control overhead. Obviously, k controls the density of redundant paths in the proposed TBM k algorithm that is a distributed algorithm to locally discover k-hop redundant paths. According to the performance evaluation results, the packet loss ratio of TBM k is less than 3 percent with k of 1, 2 and 3 while that of the multicast tree is 14 ~ 18 percent at the node speed range of 0 ~ 20 m/sec; i.e., the packet delivery performance is improved by a factor of up to 6.