Multi-radio Multi-channel Wireless Mesh Networks Research Articles

Joint multicast routing and channel assignment for multi-radio multi-channel wireless mesh networks with hybrid traffic

In this paper, joint multicast routing and channel assignment problem in wireless mesh networks (WMNs) with hybrid traffic is investigated. Previous works design routing and channel assignment schemes for WMNs with single multicast session, however, resource usage is optimized for only one multicast session in this case and overall network load balance is left out of consideration. This may result in high congestion in some links, while others are underutilized. In this paper, multicast routing and channel assignment problem is solved from traffic management perspective by introducing load balance. Programming formulation is formulated to obtain the optimal results which can be used as benchmark to evaluate other schemes. Multicast weighted conflict graph is designed to model partially overlapped channels (POCs) interference in hybrid traffic scene. It regards links originating from the same node as one transmission to fully exploit wireless broadcast advantage; it uses link weight to measure interference degree and gives full consideration to interference characteristics of POCs. A heuristic multicast routing and channel assignment scheme based on multicast weighted conflict graph is designed to solve the joint problem, and simulation results show that the heuristic scheme can reduce network interference and improve WMNs service capability while dramatically reducing computational complexity.

A Survey on Channel Assignment Techniques of Multi-Radio Multi-channel Wireless Mesh Network

Wireless Mesh Network is a promising network standard as it provides reasonable and inexpensive solutions for various types of applications. In the recent times, it has gradually developedin the direction of Multi-Radio Multi-Channel Wireless Mesh Network(MRMC WMN) architecture, which improves performance of network by providing multiple radio interfaces to every node in the network and by equipping several non-overlapping channels. In this paper, research work of variousauthors has been analyzed and found that various authors proposed modified channel assignment techniques to improve the network performance.Lot of different methods and techniques are used by them to reduce the co-channel interference. It is found that very few authors measured the traffic flow in network for channel assignment. It is asalient area and it must be carefully examined during the channel assignment. In this study, it is observed that traffic flow along with power control and topology control must be considered for efficientchannel assignment.Channel assignment is essential to make sure the best possible utilization of a few numbers of channels in the frequency spectrum.Efficient utilization of MRMC WMN can be obtained by intelligent and dynamic channel assignment.

An optimization framework for multicasting in MCMR wireless mesh network with partially overlapping channels

This paper focuses on the problem of maximizing throughput in multicast routing in Multi-Channel, Multi-Radio (MCMR) wireless mesh network. We propose an optimization framework based on binary integer programming that minimizes interference in multicast communication. Our Multicasting with multiple Gateways and Partially Overlapped Channels (MG-POC) framework utilizes a rational node selection to construct multicast tree that increases network performance. MG-POC is efficient as it (1) constructs the paths between source and receivers with minimal number of data forwarding nodes; (2) employs multiple gateways to substantially reduce interference and usage of resources; (3) benefits from wireless broadcast advantage and partially overlapped channels in channel assignment; (4) solves channel assignment and tree construction problems simultaneously. A weakly decoupled approach is also presented which finds a nearly optimal solution for large network problems in a reasonably short amount of time. Our schemes are proved to offer a connected and loop-free tree; and their performance are well compared to that of several existing methods on different simulation scenarios. The results of our simulations also demonstrate that incorporating multi-gateway and partially overlapping channels has a significant impact on minimizing network interference which, in turn, dramatically enhances network throughput.

Fault-tolerant interference-aware topology control in multi-radio multi-channel wireless mesh networks

Wireless Mesh Networks offer an effective technology to establish broadband wireless services. Due to this application, robustness against failures and throughput improvement are the two main objectives in designing such networks. In this paper, we use the “topology control” as a set of tools to reach these objectives. Topology control in wireless mesh networks is an NP-hard problem; therefore, we propose a heuristic method known as Fault-Tolerant Interference-Aware Topology Control (FITC) to solve it in a distributed fashion. In this method, we first guarantee that the network is K-Connected using the graph modification, routing and channel assignment. Then, power control, rate adaptation, channel selection and scheduling is applied to enhance the network throughput. Due to the static channel assignment and the fixed location of the nodes in the network, the first part of the algorithm is conducted using a centralized method, while a distributed cross layer method is applied for the second part. Simulation results validate the efficiency of the proposed method in achieving the main objectives.

Robust topology construction method with radio interface constraint for multi-radio multi-channel wireless mesh network using directional antennas

Multi-radio and multi-channel wireless mesh networks using directional antenna (MR-MC DWMN) greatly improve the spatial reuse of wireless channels and increase network capacity. However, the number of directional radio interfaces in MR-MC DWMN affects topology reliability and survivability. This article focuses on the construction of robust topology with radio interface constraints in MR-MC DWMN. Because of the limitation of the number of directional radio interfaces, we first formulate this topology optimization problem with directional radio interface constraints to be equivalent to establish k-connected topology with node degree constraints and then propose a robust topology construction algorithm with directional radio interface constraint. We define the link weight based on node degree and then use graph theory to construct the robust topology with node degree constraints. The proposed constructing robust topology with directional radio interface constraint can not only establish k-connected topology but also minimize the maximum node degree and meet the requirement of radio interface constraints. Simulation shows that constructing robust topology with directional radio interface constraint obtains less maximum node degree and average path length than existing k-connected topology control algorithms under the limitation of directional radio interfaces. Moreover, the constructing robust topology with directional radio interface constraint achieves better network performance than other algorithms.

Partially overlapped channels- and flow-based end-to-end channel assignment for multi-radio multi-channel wireless mesh networks

Capacity reduction is a major problem faced by wireless mesh networks. An efficient way to alleviate this problem is proper channel assignment. Current end-toend channel assignment schemes usually focus on the case where channels in distinct frequency bands are assigned to mesh access and backbone, but actually backbone network and access network can use the same IEEE 802.11 technology. Besides, these channel assignment schemes only utilize orthogonal channels to perform channel assignment, and the resulting network interference dramatically degrades network performance. Moreover, Internet-oriented traffic is considered only, and peer-to-peer traffic is omitted, or vice versa. The traffic type does not match the practical network. In this paper, we explore how to exploit partially overlapped channels to perform end-to-end channel assignment in order to achieve effective end-to-end flow transmissions. The proposed flow-based end-to-end channel assignment schemes can conquer the limitations aforementioned. Simulations reveal that loadaware channel assignment can be applied to networks with stable traffic load, and it can achieve near-optimal performance; Traffic-irrelevant channel assignment is suitable for networks with frequent change of traffic load, and it can achieve good balance between performance and overhead. Also, partially overlapped channels' capability of improving network performance is situation-dependent, they should be used carefully.

An Efficient Mac Protocol for Reducing Channel Interference and Access Delay in Cognitive Radio Wireless Mesh Networks

With the increase of wireless mesh networks, channel access, bandwidth usage and channel interferences are the major key issues of multi-channel WMNs and MAC specifications. The multi-radio, multi-channel wireless mesh networks (MR-MC-WMNs) are a kind of networks that provide high reliable communication for a large number of mesh nodes. These networks have mesh routers and channels that are stationary and each router or node has multiple channels. Although IEEE 802.11 versions support up to 3 and 12 multiple non-overlapping channels, it is the major challenge of the multichannel environment which exploits all channels to communicate a large volume of network data in WMNs. Cognitive radio users has the capability to access unused portion of the multichannel spectrum. The major interference can be created by CR as well as licensed user. Traditional MAC based operations are implemented using common-control-channel to handle cognitive radio end users. We proposed a new Multi-objective based CMR-MC-WMNs framework using TDMA based MAC protocol to optimize the network performance, channel interference and access delay issues in the network. Experimental results prove that, proposed work has less delay and inference rates compared to traditional models.

A framework to compare topology algorithms in multi-channel multi-radio wireless mesh networks

Creating an optimal topology for a multi-channel multi-radio wireless mesh network by an algorithm is a balancing act between different metrics such as bandwidth, delay, and redundancy. We propose a framework to quickly evaluate and compare resulting network graphs of different topology algorithms, both distributed and centralized, in wireless mesh networks. This framework complements to graph analysis and network simulation. The metrics presented in this paper, are both data flow (such as bandwidth capacity, delay, and loss) and structural characteristics (such as minimal edge and node cut) related. Each presented metric can be solved using a linear programming with the weighted incidence matrix of the network graph and the protocol interference model. The framework uses matrix operations, which are well established, making the framework unambiguous and easy to implement. We demonstrate the framework by comparing topology algorithms with increasing complexity and by comparing topology algorithms found in literature.

A cross-layer approach for multi-layer multicast routing in multi-channel multi-radio wireless mesh networks

In this paper, we consider multicast applications with bandwidth heterogeneous receivers in multi-channel multi-radio wireless mesh networks MC-MR WMNs. Multi-layering is a well-established approach to handle bandwidth heterogeneity of the receivers. Existing multi-layering schemes have addressed only single-channel settings. In the context of MC-MR WMNs, the channel assignment problem is coupled with multicast routing, thus necessitating a cross-layer solution. In this paper, we propose an optimal cross-layer model, which aims at maximising the total number of obtained layers by the receivers. We include network coding in our design to take advantage of its capacity boosting in multicasting. To alleviate time complexity of the optimal model, we propose grouping-based multi-layer multicast GMLMC algorithm, which yields close to optimal throughput, i.e., nearly 96% of the optimum, in polynomial time. Moreover, the pattern of layer reception to the receivers in the outcomes of GMLMC resembles very much to the optimal results.

Optimal and heuristic algorithms for constructing interference-free multicast trees subject to delay and energy constraints on wireless mesh networks

Due to the great concerns of environmental protection and the high rising of prices in oil, energy efficiency has become an important factor for designing network applications. In this paper, we study an optimisation problem which is concerned about how to construct an interference free multicast tree subject to delay and energy constraints on a multi-channel multi-radio wireless mesh network. Our objective is to maximise the number of mesh clients that can be included in the multicast tree. This problem is referred as the EDMRM problem. To solve it, we first propose an optimal algorithm on the basis of integer linear programming ILP for the EDMRM problem. Since the ILP-based method is only feasible for small-scale networks, we also provide a tabu-based heuristic algorithm for solving practical networks that consist of a large number of nodes. The experimental results show that our tabu-based heuristic can outperform the other previously proposed methods.

Routing and Channel Assignment for Multicast in Multi-Channel Multi-Radio Wireless Mesh Networks

Routing and Channel Assignment for Multicast in Multi-Channel Multi-Radio Wireless Mesh Networks

A Broadcast Channel Assignment Mechanism based on The Broadcast Tree for Multi-radio Multi-channel Wireless Mesh Networks

This paper proposed a broadcast Channel Assignment Mechanism on base of optimized Broadcast Tree for wireless Mesh network (WMN), which is created by Branch and Bound Method. The simulations show that our algorithm not only reduces the broadcast redundancy but also avoids the potential channel interferences produced by unnecessary relay nodes.

Learning Automata Based Channel Assignment with Power Control in Multi-Radio Multi-Channel Wireless Mesh Networks

Wireless channel assignment is one of the major challenging issues in multi hop wireless mesh networks (WMN) when there is the need to design them in a distributed fashion, specifically for multi-radio multi-channel (MRMC) systems. In this work, a new learning automata based channel and power assignment scheme which adaptively improve network overall throughput by expecting network dynamics was proposed. First, a utility function which reflected the user’s preference for the signal to interference and noise ratio (SINR) was applied, and then the transmitter power. The distributed channel assignment and power control problem is formulated as a multiple payoff stochastic game of automata. In this game, each user evaluates a channel and power selection strategy by computing a utility value. This evaluation is performed using a stochastic iterative procedure. The utility function that potentially reflected a measure of satisfaction of every node was used by every node as an environmental response for the current selected strategy chosen by the nodes. According to dynamics of system, the proposed algorithm assigned channels and powers to radio interface such that it minimized interference in the neighborhood of a node. The stability of the system was analyzed via appropriate Lyapunov-like trajectory; it was shown that the stability and optimum point of the system converged.

Joint Channel Assignment and Routing in Multiradio Multichannel Wireless Mesh Networks: Design Considerations and Approaches

Multiradio wireless mesh network is a promising architecture that improves the network capacity by exploiting multiple radio channels concurrently. Channel assignment and routing are underlying challenges in multiradio architectures since both determine the traffic distribution over links and channels. The interdependency between channel assignments and routing promotes toward the joint solutions for efficient configurations. This paper presents an in-depth review of the joint approaches of channel assignment and routing in multiradio wireless mesh networks. First, the key design issues, modeling, and approaches are identified and discussed. Second, existing algorithms for joint channel assignment and routing are presented and classified based on the channel assignment types. Furthermore, the set of reconfiguration algorithms to adapt the network traffic dynamics is also discussed. Finally, the paper presents some multiradio practical implementations and test-beds and points out the future research directions.

SDN-Based Resource Allocation for Multi-Channel Wireless Mesh Networks

In emerging multi-radio multi-channel wireless mesh networks (WMNs), how to allocate network resources to provide individual users with their fair rate share is a central but very complex issue due to their inherent multi-channel diversity and multi-hop connectivity. In this paper, we attempt to apply and extend a software-defined networking (SDN) approach to user-level fair resource allocation problems where both proportional fairness and max-min fairness are examined. We first mathematically formulate fair user resource allocation problems in multi-channel WMNs by seeking the maximization of objective functions under the network utility maximization framework. We then design both SDN controller-side and user device-side algorithms to solve the formulated problem in a centralized holistic manner. We apply the algorithms to control per-user link-layer rates according to a fairness criterion while we resort to traditional transport-layer congestion control for the regulation of individual flows for each user. For performance evaluation, we conduct a system-level simulation study to verify the convergence property of the proposed user fairness resource allocation solution and highlight the benefits of the SDN approach.

A novel adaptive spectrum allocation scheme for multi-channel multi-radio wireless mesh networks

The rapidly developed wireless services and applications have an increasing demand of spectrum resource, which is actually limited. Therefore, how to allocate spectrum resource effectively for network throughput improvement is an urgent issue. Although the utilization of spectrum can be enhanced by link scheduling for spatial reuse, Network Coding (NC) for broadcast transmission, multicast transmission and multi-channel multi-radio techniques, their interactions cannot be ignored. This is because on one hand, the achieved network performance by NC is strongly dependent on the MAC layer, and greedy NC method may in fact reduce network throughput owing to the reduction of spectrum spatial reuse. On the other hand, channel assignment faces more challenges brought by NC and multicast transmission since the broadcast or multicast links are dominated by the link with the worst channel state. In order to utilize the spectrum resource adaptively while not bringing additional constraints, we present a two-phase solution approach. On the first step, we formulate the NC-aware scheduling scheme to an optimization problem, by which the interference-free links are allocated into the same link set and can be activated in the same time slot and channel. Then, we assign different channels to the link sets according to the radio constraints in a heuristic method, which can further increase the utilization of spectrum resource. Finally, simulation results demonstrate that our proposed method can largely increase the utilization of spectrum resource and improve network throughput.

Interference mitigation in wireless mesh networks through radio co-location aware conflict graphs

Wireless Mesh Networks (WMNs) have evolved into a wireless communication technology of immense interest. But technological advancements in WMNs have inadvertently spawned a plethora of network performance bottlenecks, caused primarily by the rise in prevalent interference. Conflict Graphs are indispensable tools used to theoretically represent and estimate the interference in wireless networks. We propose a generic algorithm to generate conflict graphs which is independent of the underlying interference model. Further, we propose the notion of radio co-location interference, which is caused and experienced by spatially co-located radios in multi-radio multi-channel WMNs. We experimentally validate the concept, and propose a new all-encompassing algorithm to create a radio co-location aware conflict graph. Our novel conflict graph generation algorithm is demonstrated to be significantly superior and more efficient than the conventional approach, through theoretical interference estimates and comprehensive experiments. The results of an extensive set of ns-3 simulations run on the IEEE 802.11g platform strongly indicate that the radio co-location aware conflict graphs are a marked improvement over their conventional counterparts. We also question the use of total interference degree as a reliable metric to predict the performance of a Channel Assignment scheme in a given WMN deployment.

Delay analysis of parallel redundancy transmission in lossy multi-channel multi-radio wireless mesh networks

Delay analysis of parallel redundancy transmission in lossy multi-channel multi-radio wireless mesh networks

Channel Allocation in Multi-radio Multi-channel Wireless Mesh Networks: A Categorized Survey

Wireless mesh networks are a special type of broadcast networks which cover the qualifications of both ad-hoc as well as infrastructure mode networks. These networks offer connectivity to the last mile through hop to hop communication and by comparatively reducing the cost of infrastructure in terms of wire and hardware. Channel assignment has always been the focused area for such networks specifically when using non-overlapping channels and sharing radio frequency spectrum while using multiple radios. It has always been a challenge for mesh network on impartial utilization of the resources (channels), with the increase in users. The rational utilization of multiple channels and multiple radios, not only increases the overall throughput, capacity and scalability, but also creates significant complexities for channel assignment methods. For a better understanding of research challenges, this paper discusses heuristic methods, measurements and channel utilization applications and also examines various researches that yield to overcome this problem. Finally, we highlight prospective directions of research.

I-QCA: An intelligent framework for quality of service multicast routing in multichannel multiradio wireless mesh networks

Multicast routing has brought a revolution by enabling the delivery of the same content to a group of receivers simultaneously. However, multicast routing in multichannel multiradio wireless mesh networks has been proved to be an NP-hard problem. To achieve optimal performance in multichannel multiradio wireless mesh networks the channel assignment strategy plays an important role. In this paper, we present an intelligent Quality of service multicast routing and Channel Assignment (i-QCA) algorithm which solves the multicast tree construction and channel assignment problem conjointly by intelligent computational methods. The multicast tree construction algorithm is based on the differential evolution approach. The channel assignments in prior works are mostly oriented toward heuristic or meta heuristic approaches and hence produce suboptimal results. The proposed algorithm consists of a genetic algorithm based channel assignment strategy and determines a delay, jitter bounded minimal interference lowcost multicast tree. Our experimental results clearly show that the proposed algorithm achieves much better performance as compared to Multi Channel Multicast (MCM) and QoS Multicast Routing and Channel Assignment (QoS-MRCA) algorithm in multichannel multiradio wireless mesh network environments.