Broadcasting and Topology Control in Wireless Ad Hoc Networks

Network wide broadcasting in Mobile Ad Hoc Networks (MANET) provides important control and route establishment functionality for a number of unicast and multicast protocols. We present an overview of the recent progress of broadcasting and multicasting in wireless ad hoc networks. We discuss two energy models that could be used for broadcast: one is non-adjustable power and one is adjustable power. If the power consumed at each node is not adjustable, minimizing the total power used by a reliable broadcast tree is equivalent to the minimum connected dominating set problem (MCDS), i.e., minimize the number of nodes that relay the message, since all relaying nodes of a reliable broadcast form a connected dominating set (CDS). If the power consumed at each node is adjustable, we assume that the power consumed by a relay node u is ‖uv‖ , where real number β ∈ [2, 5] depends on transmission environment and v is the farthest neighbor of u in the broadcast tree. For both models, we reviewed several centralized methods that compute broadcast trees consuming the energy within a constant factor of the optimum if the original communication graph is unit disk graph. Since centralized methods are expensive to implement, We further reviewed several localized methods that can approximate the minimum energy broadcast tree for non-adjustable power case. For adjustable power case, no localized methods can approximate the minimum energy broadcast tree and thus review several currently best possible heuristics. Several local improvement methods and activity scheduling of nodes (active, idle, sleep) are also