Distributed joint flow-radio and channel assignment using partially overlapping channels in multi-radio wireless mesh networks

Equipping mesh nodes with multiple radios that support multiple wireless channels is considered a promising solution to overcome the capacity limitation of single-radio wireless mesh networks. However, careful and intelligent radio resource management is needed to take full advantage of the extra radios on the mesh nodes. Flow-radio assignment and channel assignment procedures should obey the physical constraints imposed by the radios as well as the topological constraints imposed by routing. Varying numbers of wireless channels are available for the channel assignment procedure for different wireless communication standards. To further complicate the problem, the wireless communication standard implemented by the radios of the wireless mesh network may define overlapping as well as orthogonal channels, as in the case of the IEEE 802.11b/g family of standards. This paper presents Distributed Flow-Radio Channel Assignment, a distributed joint flow-radio and channel assignment scheme and the accompanying distributed protocol in the context of multi-channel multi-radio wireless mesh networks. The scheme’s performance is evaluated on small networks for which the optimal flow-radio and channel configuration can be computed, as well as on large random topologies. © 2015, Springer Science+Business Media New York

Distributed joint flow-radio and channel assignment using partially overlapping channels in multi-radio wireless mesh networks

Equipping mesh nodes with multiple radios that support multiple wireless channels is considered a promising solution to overcome the capacity limitation of single-radio wireless mesh networks. However, careful and intelligent radio resource management is needed to take full advantage of the extra radios on the mesh nodes. Flow-radio assignment and channel assignment procedures should obey the physical constraints imposed by the radios as well as the topological constraints imposed by routing. Varying numbers of wireless channels are available for the channel assignment procedure for different wireless communication standards. To further complicate the problem, the wireless communication standard implemented by the radios of the wireless mesh network may define overlapping as well as orthogonal channels, as in the case of the IEEE 802.11b/g family of standards. This paper presents Distributed Flow-Radio Channel Assignment, a distributed joint flow-radio and channel assignment scheme and the accompanying distributed protocol in the context of multi-channel multi-radio wireless mesh networks. The scheme’s performance is evaluated on small networks for which the optimal flow-radio and channel configuration can be computed, as well as on large random topologies. © 2015, Springer Science+Business Media New York

Distributed optimal congestion control and channel assignment in wireless mesh networks

Wireless mesh networks have numerous advantages in terms of connectivity as well as reliability. Traditionally the nodes in wireless mesh networks are equipped with single radio, but the limitations are lower throughput and limited use of the available wireless channel. In order to overcome this, the recent advances in wireless mesh networks are based on multi-channel multi-radio approach. Channel assignment is a technique that selects the best channel for a node or to the entire network just to increase the network capacity. To maximize the throughput and the capacity of the network, multiple channels with multiple radios were introduced in these networks. In the proposed system, algorithms are developed to improve throughput, minimise delay, reduce average energy consumption and increase the residual energy for multi radio multi-channel wireless mesh networks. In literature, the existing channel assignment algorithms fail to consider both interflow and intra flow interferences. The limitations are inaccurate bandwidth estimation, throughput degradation under heavy traffic and unwanted energy consumption during low traffic and increase in delay. In order to improve the performance of the network distributed optimal congestion control and channel assignment algorithm (DOCCA) is proposed. In this algorithm, if congestion is identified, the information is given to previous node. According to the congestion level, the node adjusts itself to minimise congestion

Minimizing information asymmetry interference using optimal channel assignment strategy in wireless mesh networks

Multi-radio multi-channel wireless mesh networks (MRMC-WMNs) in recent years are considered as the prioritized choice for users due to its low cost and reliability. MRMCWMNs is recently been deployed widely across the world but still these kinds of networks face interference problems among WMN links. One of the well-known interference issue is information asymmetry (IA). In case of information asymmetry interference the source mesh nodes of different mesh links cannot sense each other before transmitting data on the same frequency channel. This non-coordination leads to data collision and packet loss of data flow and hence degrades the network capacity. To maximize the MRMC-WMN capacity and minimize IA interference, various schemes for optimal channel assignment have been proposed already. In this research a novel and near-optimal channel assignment model called Information Asymmetry Minimization (IAM) model is proposed based on integer linear programming. The proposed IAM model optimally assigns orthogonal or non-overlapping channels from IEEE 802.11b technology to various MRMC-WMN links. Through extensive simulations we show that our proposed model gives 28.31% network aggregate network capacity improvement over the existing channel assignment model

Analysis and mitigation of interference in multi-radio multi-channel wireless mesh networks

Ankara : The Department of Computer Engineering and the Graduate School of Engineering and Science of Bilkent Univ., 2013.Thesis (Ph. D.) -- Bilkent University, 2013.Includes bibliographical references leaves 162-170.Wireless mesh networking, which is basically forming a backbone network of mesh routers using wireless links, is becoming increasingly popular for a broad range of applications from last-mile broadband access to disaster networking or P2P communications, because of its easy deployment, self-forming, self-configuration, and self-healing properties. The multi-hop nature of wireless mesh networks (WMNs) aggravates inter-flow interference and causes intra-flow interference and severely limits the network capacity. One technique to mitigate interference and increase network capacity is to equip the mesh routers with multiple radios and use multiple channels. The radios of a mesh router can then simultaneously send or receive packets on different wireless channels. However, careful and intelligent radio resource planning, including flow-radio and channel assignment, is necessary to efficiently make use of multiple radios and channels. This first requires analyzing and modeling the nature of co-channel and adjacent channel interference in a WMN. Through real-world experiments and observations made in an indoor multihop multi-radio 802.11b/g mesh networking testbed we established, BilMesh, we first analyze and model the nature of co-channel and adjacent channel interference. We conduct extensive experiments on this testbed to understand the effects of using multi-radio, multi-channel relay nodes in terms of network and application layer performance metrics. We also report our results on using overlapping in addition to orthogonal channels for the radios of the mesh routers. We then turn our attention to modeling and quantifying adjacent channel interference. Extending BilMesh with IEEE 802.15.4 nodes, we propose computational methods to quantify interference between channels of a wireless communication standard and between channels of two different standards (such as Wi-Fi and ZigBee). Majority of the studies in the literature on channel assignment consider only orthogonal channels for the radios of a multi-radio WMN. Having developed quantitative models of interference, next we propose two optimization models, which use overlapping channels, for the joint flow-radio and channel assignment problems in WMNs. Then we propose efficient centralized and distributed heuristic algorithms for coupling flows and assigning channels to the radios of a WMN. The proposed centralized and distributed schemes make use of overlapping channels to increase spectrum utilization. Using solid interference and capacity metrics, we evaluate the performances of the proposed schemes via extensive simulation experiments, and we observe that our schemes can achieve substantial improvement over single-channel and random flow-radio and channel assignment schemes.Uluçınar, Alper RifatPh.D

Near Optimal Channel Assignment for Interference Mitigation in Wireless Mesh Networks

In multi-radio multi-channel (MRMC) WMNs, interference alleviation is affected through several network design techniques e.g., channel assignment (CA), link scheduling, routing etc., intelligent CA schemes being the most effective tool for interference mitigation. CA in WMNs is an NP-Hard problem, and makes optimality a desired yet elusive goal in real-time deployments which are characterized by fast transmission and switching times and minimal end-to-end latency. The trade-off between optimal performance and minimal response times is often achieved through CA schemes that employ heuristics to propose efficient solutions. WMN configuration and physical layout are also crucial factors which decide network performance, and it has been demonstrated in numerous research works that rectangular/square grid WMNs outperform random or unplanned WMN deployments in terms of network capacity, latency, and network resilience. In this work, we propose a smart heuristic approach to devise a near-optimal CA algorithm for grid WMNs (NOCAG). We demonstrate the efficacy of NOCAG by evaluating its performance against the minimal-interference CA generated through a rudimentary brute-force technique (BFCA), for the same WMN configuration. We assess its ability to mitigate interference both, theoretically (through interference estimation metrics) and experimentally (by running rigorous simulations in NS-3). We demonstrate that the performance of NOCAG is almost as good as the BFCA, at a minimal computational overhead of O(n) compared to the exponential of BFCA

On-demand Multi-Rate, Carrier Sense and Hidden Node Interference-Aware Channel Assignment Scheme in Wireless Mesh Network

The proposed interference avoidance channel assignment schemes can provide a significant advantage in term of aggregated throughput by assigning channels only to the active nodes and minimizing the intra-flow and inter-flow interference caused by hidden nodes. However, the negative aspect of the channel assignment schemes for the multi-rate multi-hop wireless mesh networks is the capacity reduction caused by channel reuse over low and high data rate links at the carrier sense and hidden node ranges. This paper proposed an On-demand Multi-Rate, Carrier Sense and Hidden node Interference-Aware channel assignment scheme (AODV-MRCSHDIA) to minimize the interference caused by low rate links at the carrier sense and hidden node ranges on the network throughput. The simulation experiment has been conducted to evaluate the AODVMRCSHDIA over the existing schemes in term of packet delivery ratio and end-to-end delay

An Efficient Hybrid Channel Assignment Protocol for a Multi Interface Wireless Mesh Network

ABSTRACT: In Both multi-interface and dynamicchannel adjustment are prevailingly used to improve thecapacity and the flexibility of wireless mesh networks(WMNs). The System over heads that are generated by uncontrolled interface switching adversely decrease the performance of WMNs. To find a reasonable tradeoff between flexibility and switching overheads, we propose ahybrid channelassignment protocol (HCAP) for multiinterface WMNs. The HCAP adopts a static interfaceassignment strategy for nodes that have the heaviest loads to avoid frequent interface switching, whereas it adopts a hybrid interfaceassignment strategy for other nodes to improve the ability of adapting to flow change. In our implementation, we present a slotbased coordination policy. Extensive NS2 simulations demonstrate that the HCAP improves network capacity, enhances flexibility, and guarantees interflow fairness. KEYWORDS: Channel assignment, coordination, interface switching, multiple interfaces, wireless mesh network (WMN). I. INTRODUCTION In deployment of wireless mesh networks (WMNs) has quickly increased recently due to their significant advantages over other wireless networks. A typical WMN application consists of three levels: wired networks, the WMN backbone, and mesh clients. Wired networks contain most resources in WMNs, such as file servers, file transfer protocol servers, etc. The WMN backbone is a collection of static wireless mesh routers. Traffic loads between the wired network and mobile users in mesh clients are transmitted by the WMN backbone in a multihop manner. Mesh clients can connect to the WMN backbone by establishing either wired or wireless links with mesh routers. Most wireless networks, such as wireless local area networks, wireless metropolitan area net-works, wireless wide area networks, wireless sensor networks, wireless personal area networks, and cellular networks, can act as mesh clients. One example of WMN architecture is shown in We propose a novel channelassignment protocol for multi-interface WMNs. The proposed protocol does not need prior knowledge of loads. Nevertheless, it can automatically adapt to load change