Online network coding-based multicast routing in multichannel multiradio wireless mesh networks

Turkish Journal of Electrical Engineering & Computer Sciences http://journals.tubitak.gov.tr/elektrik/ Research Article Turk J Elec Eng & Comp Sci (2019) 27: 1387 – 1405 © TÜBİTAK doi:10.3906/elk-1808-167 Online network coding-based multicast routing in multichannel multiradio wireless mesh networks Leili FARZINVASH∗, Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran Received: 23.08.2018 • Accepted/Published Online: 13.01.2019 • Final Version: 22.03.2019 Abstract: In this paper, we consider the problem of online multicast routing in multichannel multiradio wireless mesh networks (WMNs). We propose an efficient online algorithm, namely zone-based multicast routing (ZBMR), which exploits network coding and wireless broadcast advantage. In the proposed algorithm, to investigate the acceptance of an arrived session in polynomial time, the WMN is divided into some zones. The derived zones are processed sequentially, where the zone processing is defined as connecting the receivers in a given zone to the session. The main challenge in this scheme is to enable data transmission to the receivers in each zone. If a zone does not contain the source node, it should obtain data from the previously processed neighboring zones. The problem is that the data transmission fails if there is no receiver on the common border between the considered zone and its processed neighboring zones. Our solution to tackle this challenge is to add some virtual receivers to the borders of the zones. The extensive simulations show that ZBMR increases the acceptance rate by 50% in comparison to the previous approaches. Key words: Wireless mesh network, online multicast routing, multichannel multiradio, network coding, polynomial time, wireless broadcast advantage 1. Introduction With the emergence of multicast applications, designing effective algorithms for group communication has drawn significant attention [1]. One important domain where multicast routing is widely used is broadband wireless mesh networks (WMNs). These networks provide Internet connectivity in rural and metropolitan areas. From the popular multicast-based services in WMNs, we can point out online games, video conferencing, distance education, and online TV. The mentioned applications typically require a considerable amount of bandwidth. Therefore, it is critical to develop high-throughput multicast routing algorithms. Recently, the network coding (NC) technique has been proposed as a bandwidth-efficient solution to perform multicast routing. In this scheme, the ingress flows to each relay node are coded with each other. This coding scheme reduces bandwidth utilization in comparison to the tree structure [2], which enhances the performance of the system. Some studies on multicast routing in WMNs have employed this technique [3–14]. The main shortcoming of these works is that they studied offline scenarios. In other words, they assumed that the multicast sessions are given in advance. Consequently, they cannot handle online multicast routing, in which the sessions arrive at the system dynamically. To support online applications, in this paper we investigate the problem of online NC-based multicast routing in WMNs. In the proposed setting, it is assumed that each multicast session demands a specific bandwidth. In addition, the arrival time and duration of the sessions are unknown before. A session is accepted ∗ Correspondence: 1387 This work is licensed under a Creative Commons Attribution 4.0 International License. FARZINVASH/Turk J Elec Eng & Comp Sci if its bandwidth requirement can be satisfied. To increase the acceptance rate, we adopt the multichannel multiradio (MC-MR) setting. In this scheme, the nodes are equipped with some radios and utilize multiple channels for data transmission [15]. Therefore, the amount of interference throughout the network decreases. The wireless broadcast advantage (WBA) is also included in our design to improve the acceptance rate as much as possible. Using this property in multicast routing, the data sent by a node using a specific channel are obtained by all of its children to which the same channel is assigned. Therefore, the amount of utilized bandwidth for multicast routing reduces substantially. While exploiting WBA in NC-based multicast routing, the challenge is that the children of the nodes have to be determined during data transmission. The parent-child relationship between the nodes is modeled using binary variables. As a result, the optimal model for the acceptance of arrived sessions becomes mixed integer programming (MIP). Due to NP-hardness of MIP models [16], the time complexity of the intended problem is not acceptable for online services. Therefore, we design the zone-based multicast routing (ZBMR) algorithm considering the optimal model. This algorithm comprises two phases of zone formation and zone processing, which are described below. When a multicast session arrives, the WMN is divided into disjoint zones. In the proposed zone formation scheme, the nodes are traversed in breadth-first search (BFS) order from the source node of the session. While considering a given node, the corresponding binary variables to the common links between the node and previously processed nodes are added to the current zone. The number of binary variables in each zone, which presents the parent-child relationship between the nodes regarding the arrived session, is limited to a given threshold. Accordingly, when the number of binary variables in the current zone reaches the threshold, the binary variables corresponding to the subsequent visited links are added to the next zone. This procedure continues until all nodes are processed. After forming the zones, they are processed sequentially. The aim of the zone processing scheme is to deliver the multicast data to the included receivers. To this end, it employs a mathematical model, which is based on the optimal model. This model performs NC-based multicast routing, link scheduling, and exploitation of WBA within the assumed zone. The zone is processed successfully if there is enough bandwidth to transmit multicast data to all of its receivers. The session is accepted if all zones are processed successfully. As the number of binary variables in each zone is less than the predefined threshold, the time complexity of processing of a given zone is polynomial regarding the network parameters. Consequently, the proposed algorithm becomes polynomial time. In the proposed zone processing scheme, the zone that contains the source node is processed first. Next, the neighboring zones of the previously processed zones are considered. This procedure continues until all zones are processed. The important issue in this scheme is that data transmission between two neighboring zones may fail if the sender zone has no receiver on its border. This is because there is no guarantee that the nonreceiver nodes obtain the multica (...truncated)