Improved heuristics for multicast routing in wireless mesh networks Rakesh Matam • Somanath Tripathy Ó Springer Science+Business Media New York 2013 Abstract Multicast is a communication technique that allows a source to transmit data to a set of recipients in an efficient manner. Therefore, the primary objective of a multicast routing protocol would be to minimize number of transmissions to conserve bandwidth. The problem of computing multicast trees with minimal bandwidth con- sumption is similar to Steiner tree problem and has shown to be NP-complete. So, heuristic based algorithms are suitable to approximate such bandwidth optimal trees. This paper proposes a multicast routing protocol based on minimum number of transmission trees using an heuristic approach. The simulation results show that the proposed algorithm offers better performance over existing protocols, even in the worst-case scenario when the set of multicast receivers are sparsely distributed across the network. Keywords Multicast routing  Wireless mesh network  Heuristic based algorithms  Steiner tree 1 Introduction Wireless mesh networks (WMNs) have emerged as a promising technology for next-generation wireless net- working [2]. A typical WMN is comprised of a set of mesh routers (MRs) and mesh clients (MCs). Mesh routers are wireless routers, equipped with one or more wireless interfaces and are more or less stationery. Mesh routers along with mesh access points and gateway routers form the backbone of a WMN. Mesh backbone forms the core of a WMN that provides access services to its clients. On the other hand, mesh client can be any device with networking capability. Recent popular applications of WMNs include multicast television, audio and video conferencing and multi-player social gaming [3]. These multimedia stream- ing applications require multicast transmissions for trans- portation of content. Multicast streams are particularly important when several clients wish to receive the same audio/video stream. These multicast streams are charac- terized by their requirement of high bandwidth and low latency [4]. Therefore, there is need for design of efficient multicast routing algorithms to achieve desired level of commercial success [5]. Multicast routing algorithms can be broadly classified into mesh based and tree based protocols. Various proto- cols exist that are designed based on either of the two different routing methodologies. Both categories of proto- cols have their own set of pros and cons, and therefore find suitability based on application scenario. For example, mesh based multicast protocols are well suited for mobile ad hoc networks as they can withstand against link failures that occur due to mobility [6, 7]. On the other hand, tree based routing protocols are more appropriate for WMN, where the links are more stable due to the static nature of backbone nodes [8]. There are two fundamental tree based multicast routing approaches in multi-hop wireless networks [9]. They are shortest path trees (SPTs) and minimum cost trees (MCTs). The SPT algorithms minimize the distance (or cost) from the sender to each receiver, while the MCT algorithms like minimum Steiner trees (MST’s) minimize the overall edge cost of the multicast tree [10]. MCT algorithms based on R. Matam  S. Tripathy (&) Department of Computer Science and Engineering, Indian Institute of Technology Patna, Patna 800013, Bihar, India e-mail: som@iitp.ac.in R. Matam e-mail: m.rakesh@iitp.ac.in 123 Wireless Netw DOI 10.1007/s11276-013-0575-z