Energy Efficient Management for Wireless Mesh Networks with Green Routers

In multi-channel wireless mesh networks (WMNs), it is significantly important to achieve efficient channel utilization. The channel assignment problem, which investigates how to seek a proper mapping between available channels and network interface cards (NICs) on mesh routers (MRs), is attracting more and more attention from the research community. However, most proposed channel assignment approaches assume that NICs are evenly placed on the MRs, and its amount is also pre-determined. Due to the non-uniform distribution of WMN traffic, the equal interface placement will inevitably cause that the bottleneck MRs suffer from NIC shortage, and MRs with less load only have a low utilization of NICs. Hence, in order to improve network performance and reduce network cost, interface placement should be considered carefully in the process of planning a WMN. In this paper, we investigate the joint interface placement and channel assignment problem, i.e., how to appropriately place NICs on MRs and assign channels to them. We first formulate the problem as a mixed integer linear programming (MILP) model, which aims to minimize the total number of NICs while satisfying logical link, link bandwidth, link interference and traffic demand constraints. Then, we propose an MILP-based heuristic algorithm, using iterated local search to obtain sub-optimal solutions efficiently. Finally, we conduct simulation experiments to compare the heuristic solutions with the optimal solutions, and the results show that our proposed heuristic algorithm can achieve good sub-optimal solutions. Moreover, the simulation results also demonstrate that the algorithm can be well applied in large-scale WMNs where the optimal solutions cannot be obtained, and can perform well under different traffic demands.

Wireless Mesh Network (WMN) is recently emerged network having robustness. It supports clients to communicate with different types of networks, Internet etc which provides a better service to next generation. It consists of mesh routers and mesh clients. These mesh routers are minimal mobile and mesh clients are totally mobile. The protocols of Ad hoc network are used in WMN. These protocols assume that every node is mobile. But as the mesh routers are minimal mobile or not mobile, the protocols brings overhead for the mesh routers. Our task is to relieve mesh routers using ad hoc network protocol from the overhead and define a better protocol which will fit in WMN efficiently. To do so, we've found that the existing architecture of WMN is needed to be changed slightly. We have proposed a new architecture for Wireless Mesh Network. In our proposal WMN is relieved from overhead being caused by using ad hoc network protocol. Our architecture use unicasting technique in lieu of broadcasting technique for route discovery as well as route maintenance. We will first describe the overview of WMN, its existing architecture. Later we will go to our proposed architecture.

The wireless mesh network is emerging as a promising technology in providing economical and scalable broadband Internet accesses to communities. The backbone of the wireless mesh network consists of mesh routers, which connect each other in an ad hoc manner via wireless links. The presence of backbone mesh routers and utilization of multiple channels and interfaces allow the wireless mesh network to have better capacity than that of the infrastructure-free ad hoc network formed by mesh clients directly. A special type of the mesh routers, referred to as gateway nodes, is capable of Internet connection, and other mesh routers and associated terminal clients have to access the Internet through the gateway nodes. In this paper, we present the analytically traceable stochastic models to characterize the average delay and throughput performance in wireless mesh networks. We model the forwarding mesh routers as an open queuing network. The analytical model takes into account the mesh router density, the random packet arrival process, the degree of locality of traffic and the collision avoidance mechanism of the IEEE802.11 DCF random access MAC. Our simulation results suggest that the analytical results are quite accurate, which can provide valuable insights in system performance and an effective guideline for the scalable design and optimization in wireless mesh networks.

An infrastructure wireless mesh network (WMN) is a hierarchical network consisting of mesh clients, mesh routers and gateways. Mesh routers constitute a wireless mesh backbone, to which mesh clients are connected as a star topology, and gateways are chosen among mesh routers providing Internet access. In this paper, the throughput capacity of infrastructure WMNs is studied. For such a network with Nc randomly distributed mesh clients, Nr regularly placed mesh routers and Ng gateways, assuming that each mesh router can transmit at W bits/s, the per-client throughput capacity has been derived as a function of Nc , Nr , Ng and W . The result illustrates that, in order to achieve high capacity performance, the number of mesh routers and the number of gateways must be properly chosen. It also reveals that an infrastructure WMN can achieve the same asymptotic throughput capacity as that of a hybrid ad hoc network by choosing only a small number of mesh routers as gateways. This property makes WMNs a very promising solution for future wireless networking.

There is a growing interest in ad hoc wireless networking internationally, due to the great cost in infrastructure and the time delay for deployment for new traditional wireless networks for a specific purpose (i.e. cellular systems). The interest arises from the possibility of delivering telecommunication services rapidly and with the reduced needs for costly generic infrastructure. Examples of such services include, among others, a convention where a large number of people are concentrated in a limited geographical area, a university campus with a great density of telecommunication users, or even a disaster area where the fixed infrastructure have been damaged. In most examples, ad hoc wireless networks may complement or replace the existing wireless telecommunications infrastructure. One flavor of ad hoc wireless networks that is of interest in this context, and is well adapted to the Lebanese market, are wireless mesh networks (WMN). We propose that the proliferation of WiFi hotspots in high-density areas of population in Lebanon forms the basis of deployment of mesh routers for a WMN. Of specific interest is to be able to use the dense infrastructure of GSM-EDGE (and in the future HSUPA) cellular networks in Lebanon to interconnect those routers in specific locations where it will be hard to deploy additional fixed and cumbersome cellular infrastructure. Locations where hotspots are already deployed (commercial centers, university campuses, business areas, etc.) or could be deployed for special events (conventions, concerts, etc.) could thus be interconnected in a hybrid wireless network, resulting in significantly increased capacity of the network for local voice and data traffic at little additional infrastructure cost. Furthermore, this could a preliminary step for direct connection between the mesh routers and not via the cellular network, into what will become a full- fledged WMN. The structure of the paper is as follows: section the author gives an introduction on ad hoc wireless networks; section II describes WMN and define the design issues of WMN; in section III, we look at a proposed scenario for deployment of WMNs in the Lebanese market and the issues of interconnection with the GSM networks. We will conclude in section IV.

Cognitive Radio (CR) technology constitutes a promising approach to increase the capacity of Wireless Mesh Networks (WMNs). Using this technology, Mesh Routers (MRs) and the attached Mesh Clients (MCs) are allowed to opportunis- tically transmit on the licensed band, but under the constraint not to interfere with the Primary Users (PUs) of the spectrum. Thus, the effective deployment of CR- WMNs require that each MR must be able to: sense the current spectrum, select an available PU-free channel and perform the spectrum handoff to a new channel in case of PU arrival on the current one. How to coordinate these actions in the optimal way which maximizes the performance of the CR-WMNs while minimizing the interference to the PUs constitutes an open research issue in CR systems. In this paper, we propose an adaptive spectrum scheduling and allocation scheme which allows a MR to identify the best schedule of (i) when to sense the current channel, (ii) when to transmit, (iii) when to perform a spectrum handoff. Due the large number of parameters involved, we propose Reinforcement Learning (RL) techniques to allow a MR to learn by itself the optimal balance between spectrum sensing-exploitation- exploration actions based on network feedbacks coming from the MCs. We perform extensive simulations which confirm the adaptivity and efficiency of our approach in terms of increased throughput when compared with non-learning based schemes for CR-WMNs.

In recent years, wireless mesh network (WMN) is a compelling topic to many network researchers due to its low cost in deployment, simplicity in installation and robustness in operation. However, existing routing protocols designed for MANET can not work efficiently in WMN because backbone in WMN formed by Mesh Router has very low mobility and are not put under power and memory constraint. In addition, they just concentrate on finding single path from the source to the destination while the characteristics of robustness of WMN require that every intermediate Mesh Router should establish several paths from itself to its desired destination. In our paper, we design a routing protocol that permits each MR to quickly discover multiple paths based on Hop Count metric to the Internet Gateways. Unfortunately, Hop Count does not take packet loss or bandwidth into account. It results in low throughput of a flow that follows the shortest path. A bandwidth estimation technique has been proposed to apply at each Mesh Router to allow it to predict congestion risk over its connected links and to select high available bandwidth link for forwarding packets. A detailed performance evaluation shows that the throughput increases greatly compared to pure AODV and AOMDV in high-loaded traffic scenario.

Wireless Mesh Network (WMN) is a multi hop low cost, with easy maintenance robust network providing reliable service coverage. WMNs consist of mesh routers and mesh clients. In this architecture, while static mesh routers form the wireless backbone, mesh clients access the network through mesh routers as well as directly meshing with each other. Different from traditional wireless networks, WMN is dynamically self-organized and self-configured. In other words, the nodes in the mesh network automatically establish and maintain network connectivity. Over the years researchers have worked, to reduce the redundancy in broadcasting packet in the mesh network in the wireless domain for providing reliable service coverage, the source node deserves to broadcast or flood the control packets. The redundant control packet consumes the bandwidth of the wireless medium and significantly reduces the average throughput and consequently reduces the overall system performance. In this paper I study the optimization problem in Wireless Mesh Networks. We have proposed a novel approach to reduce the broadcast redundant packet in the wireless mesh network. Also we have shown, a novel procedure to forward the control packet to the destination nodes and efficiently minimize the transmitted control packet in the wireless mesh cloud , that covers the domain.

The ‘Wireless Mesh Networks (WMNs)' is utilized to enhance the networking services and internet access in metropolitan regions, campuses, local and personal. The ‘Mesh Routers (MR)' creates the connectivity backbone while performing multiple packet transmission tasks along with providing network ingress to the mesh users. This issue can be minimized by incorporating cognitive radio that focuses on inventing the spectrum management and sensing mechanisms. Hence, there is a demand to implement a framework for the ‘optimal Dynamic Spectrum Access' (DSA) in WMN beside with cognitive thoughts. In this paper, the optimization techniques are utilized to exploit the spectral and energy effectiveness of DSA in WMN. So, a novel hybrid approach, called the Iteration-based Position of Fire Hawk and Coyote Optimization (IPFHCO) is developed in this work. The developed hybrid model, IPFHCO can effectively maximize the energy and spectral efficacy in the WMN system than the other conventional approaches while performing several analyses. The simulation outcomes shows that the spectral efficiency of the offered DSA system in WMN is enhanced by 37.5% than the DHOA, 62.5% than the Jaya, 16.66% than the FHO, and 45.83% than the COA, while taking the transmission power value as 25 bps\\Hz.

Communication limitation at the edge is widely recognized as a major bottleneck for federated learning (FL). Multi-hop wireless networking provides a cost-effective solution to enhance service coverage and spectrum efficiency at the edge, which could facilitate large-scale and efficient machine learning (ML) model aggregation. However, FL over multi-hop wireless networks has rarely been investigated. In this paper, we optimize FL over wireless mesh networks by taking into account the heterogeneity in communication and computing resources at mesh routers and clients. We present a framework that each intermediate router performs <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in-network</i> model aggregation before sending the data to the next hop, so as to reduce the outgoing data traffic and hence aggregate more models under limited communication resources. To accelerate model training, we formulate our optimization problem by jointly considering model aggregation, routing, and spectrum allocation. Although the problem is a non-convex mixed-integer nonlinear programming, we transform it into a mixed-integer linear programming (MILP), and develop a coarse-grained fixing procedure to solve it efficiently. Simulation results demonstrate the effectiveness of the solution approach, and the superiority of the in-network aggregation scheme over the counterpart without in-network aggregation.

Over the past few years, wireless mesh networks (WMNs) have emerged to become a ubiquitous solution for providing wireless access at lower cost, greater flexibility, higher reliability and performance compared to conventional wireless local area network (WLANs). As the demand for delay sensitive real-time applications such as VOIP and streaming media grows, mobility management is becoming a critical function of WMN. Although Mobility management schemes designed for Mobile Ad Hoc Networks (MANETs) and traditional fixed networks might be useful for WMNs, mobility management in WMNs is still an active research issue because of the special properties of WMNs. This chapter focuses on the mobility management in wireless mesh networks, which takes into account the unreliability of wireless mesh links and other special properties of WMNs. The chapter began by discussing the special properties of WMNs and the general concepts of mobility management, and then gives an overview of the mobility management problems in wireless mesh networks (layer 2 handoff, vertical handoff and cross layer design, etc.) with some potential solutions.

The performance of Multi-Channel Multi-Radio (MC-MR) Wireless Mesh Networks (WMNs) can be improved significantly with the increase in number of channels and radios. Despite the availability of multiple channels in several of the current wireless standards, only a few of them are non-overlapping and many channels are partially overlapped. In this paper, we formulate the joint channel assignment and flow allocation problem for MC-MR WMNs as a Mixed Integer Linear Program (MILP). Unlike most of the previous studies, we consider the case of using both non-overlapped and partially overlapped channels. We consider an objective of maximizing aggregate end-to-end throughput and minimizing queueing delay in the network, instead of the sum of link capacities, since the traffic characteristics of a multihop WMN are quite different from a single hop wireless network. Our formulation takes into consideration several important network parameters such as the transmission power of each node, path loss information, signal to interference plus noise ratio at a node, and frequency response of the filters used in the transmitter and receiver. We show by simulations that our MILP formulation makes efficient use of the spectrum, by providing superior channel assignments and flow allocations with the addition of partially overlapped channels, without the use of any additional spectrum.

Multi-channel communication in a Wireless Mesh Network with routers having multiple radio interfaces significantly enhances the network capacity. Efficient channel assignment is critical for realization of optimal throughput in such networks. This paper addresses the channel assignment problem for multi-channel multi-interface (radio) wireless mesh networks. We focus on static wireless mesh networks where multiple non-overlapping channels are available for each wireless interface. In this network environment, our objective is to find a fixed channel assignment which maximizes the number of bidirectional links that can be activated simultaneously, subject to interference constraints. We present a mixed integer linear programming models for solving the fixed channel assignment problem with multiple radios. Detailed computational results are presented and discussed to validate the algorithm.

Software Defined Networking (SDN) brings unprecedented opportunities for facilitating the management of Wireless Mesh Networks (WMNs), particularly when handling network dynamics such as link/node failures. The inflexible destination-based routing and failure recovery of conventional WMN routing protocols are superseded by the efficient and highly flexible per-flow (re)routing in SDN-based networks. Most of the existing works focus on protection by pre-computing backup paths using OpenFlow fast failover groups to reroute the flows in case of channel re-assignment or a single link failure in software-defined WMNs. However, the limitations of failure detection using link monitoring for protection have not been studied. Moreover, the potentials of restoration-based failure recovery to handle single/multiple failure scenarios, have not been fully investigated. In this paper, we implement a prototype for reactive failure recovery in multi-radio multi-channel software-defined WMNs that provides a detailed performance and sensitivity analysis. The acquired results from the SDN-based scenarios outperform the most popular conventional WMN routing protocols in terms of recovery time while preserving the best achievable throughput even when the out-of-band control network is partially impaired. We also demonstrate the limitation of link monitoring, which mainly results from the shared nature of wireless medium, for protection-based mechanisms in software-defined WMNs.

In a wireless mesh network, the traffic is aggregated at mesh router and most of them forwarded towards the Internet through GW (Internet gateway). Thus easily leads to a bottleneck for network performance at GW. Aimed to this problem ,we firstly treated the GW and mesh router as the alike node equivalently. Then used the logarithm-normal distribution model of shadow affect in wireless communication to design a weighted objective function for guarantee nodepsilas connectivity and coverage, attained the deployment location of the candidate GW; Based of the generated connectivity graph of the network and the constraints of the gateway deployment, consider a heuristic TSP (tree-set partition) algorithm based on degree/weighted to get a good choice of nodes with high throughput and better connectivity act as GW configuration. In conclusion, we validated our ideas and achieved a certain optimization effect under NS2 simulation.