Throughput-optimal broadcast in wireless networks with dynamic topology
Author(s)Tassiulas, Leandros; Sinha, Abhishek; Modiano, Eytan H
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We consider the problem of throughput-optimal broadcasting in time-varying wireless network with an underlying Directed Acyclic Graph (DAG) topology. Known broadcast algorithms route packets along pre-computed spanning trees. In large wireless networks with time-varying connectivities, the optimal trees are difficult to compute and maintain. In this paper we propose a new online throughput-optimal broadcast algorithm, which takes packet-by-packet scheduling and routing decisions, obviating the need for maintaining any global topological structures, such as spanning-trees. Our algorithm utilizes certain queue-like system-state information for making transmission decisions and hence, may be thought of as a generalization of the well-known back pressure algorithm, which makes point-to-point unicast transmission decisions based on local queue-length information. Technically, the back-pressure algorithm is derived by stabilizing the packet-queues. However, because of packet-duplications, the work-conservation principle is violated and appropriate queuing processes are difficult to define in the broadcast setting. To address this fundamental issue, we identify certain state-variables whose dynamics behave like virtual queues. By stochastically stabilizing these virtual queues, we devise a throughput-optimal broadcast policy. We also derive new characterizations of the broadcast-capacity of time-varying wireless DAGs and derive an efficient algorithm to compute the capacity exactly under certain assumptions, and a poly-time approximation algorithm for computing the capacity approximately under less restrictive assumptions.
DepartmentMassachusetts Institute of Technology. Laboratory for Information and Decision Systems
Proceedings of the 17th ACM International Symposium on Mobile Ad Hoc Networking and Computing - MobiHoc '16
Association for Computing Machinery (ACM)
Sinha, Abhishek, Leandros Tassiulas, and Eytan Modiano. “Throughput-Optimal Broadcast in Wireless Networks with Dynamic Topology.” Proceedings of the 17th ACM International Symposium on Mobile Ad Hoc Networking and Computing, 2016, Paderborn, Germany, July 05 - 08, 2016, pp. 21-30.