Probabilistic load balancing in wireless mesh networks

In a wireless mesh network (WMN), mesh clients (MCs) access the Internet through the wireless backbone formed by the Internet Gateways (IGWs) and Mesh Routers (MRs). An IGW as the traffic center may easily become the congestion center in a WMN. The load balancing between IGWs will reduce the traffic congestion thereby improving the network performance and providing a better quality of service (QoS). In this paper, potential load balancing between different IGW service domains is examined and fairness metrics are defined for both homogenous and heterogeneous WMNs. A distributed load balancing scheme based on diffusion methods is proposed to achieve a global load fairness. The effectiveness and efficiency of proposed load balancing scheme are verified by extensive simulations.

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.

Wireless Mesh Networks (WMNs) are gaining a lot of attention from researchers due to their advantages such as easy maintenance, low upfront cost and high robustness. Connectivity and stability directly affect the performance of WMNs. However, WMNs have some problems such as node placement problem, hidden terminal problem and so on. In our previous work, we implemented a simulation system to solve the node placement problem in WMNs considering Particle Swarm Optimization (PSO) and Distributed Genetic Algorithm (DGA), called WMN-PSODGA. In this paper, we compare chi-square and uniform distributions of mesh clients for different router replacement methods. The router replacement methods considered are Constriction Method (CM), Random Inertia Weight Method (RIWM), Linearly Decreasing Inertia Weight Method (LDIWM), Linearly Decreasing Vmax Method (LDVM) and Rational Decrement of Vmax Method (RDVM). The simulation results show that for chi-square distribution the mesh routers cover all mesh clients for all router replacement methods. In terms of load balancing, the method that achieves the best performance is RDVM. When using the uniform distribution, the mesh routers do not cover all mesh clients, but this distribution shows good load balancing for four router replacement methods, with RIWM showing the best performance. The only method that shows poor performance for this distribution is LDIWM. However, since not all mesh clients are covered when using uniform distribution, the best scenario is chi-square distribution of mesh clients with RDVM as a router replacement method.

The provision for addressing multiple destinations in group multimedia application delivery over Wireless Mesh Networks (WMN) can be achieved efficiently via multicasting while considering the mobility of Mesh Clients (MC). One of the prominent components of WMN is the Internet Gateway (IGW) which provides wired bridge connection between the backbone network and the Internet. In addition, its cost is significant therefore its placement is one of the main determinants of the overall performance and deployment cost of WMN. This current work explores IGW placement or deployment optimisation for the purpose of incorporation of multicasting and mobility management. Thus, the main focus in this work centres on investigating IGW placement optimisation with the intent of extracting the design issues to answer questions on the appropriateness of the problem formulation and modeling techniques for the optimisation problem. Furthermore, the paper develops the sketch of modeling and formulation of IGW placement problem with the objective of optimising IGW placement while cost of multicast tree and mobility are optimised. This formulation is different from existing works which considers only geographic positioning, load-balancing and interference-based placement. This novel formulation will serve as the basis for IGW placement and selection algorithm to address IGW deployment problem in a mobile multicast WMN architecture.

Mesh router (MR) placement is one of the fundamental issues that need to be carefully addressed to provide mesh clients with satisfactory performance in a wireless mesh network (WMN). This paper proposes a virtual force based MR placement algorithm (VFPlace) which is scalable and self- adaptive. Given a certain number of MRs, VFPlace targets to determine the positions of these MRs to maximize their overall coverage and maintain a certain number of neighbors for each MR, while satisfying geographic and traffic constraints of a specific WMN. VFPlace can dynamically avoid placing MRs in prohibitive regions, favor preferential regions and balance the distance between MRs. Moreover, VFPlace can adapt the MR placement to the highly aggregated traffic load towards Internet gateways. The effectiveness of VFPlace is demonstrated through extensive simulations.

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.

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.

Wireless mesh networks (WMNs) have recently evoked much research attention as a novel technology for last-mile broadband Internet access. When designing a WMN, gateway placement is significant for it determines the total network throughput. To address this problem, a novel gateway placement approach is proposed in this paper, in which three objectives are optimized, i.e. the number of gateways, the average MR (mesh router)-GW (gateway) hop count and the variance of gateway load. The gateway placement problem is modeled as a multiple objective linear program first, and then a two-stage load balanced gateway placement algorithm is proposed. The first stage is weight-based greedy gateway selection, and the second stage is load balanced MR attachment. Simulation results show that the algorithm behaves similarly compared with existing approaches in both number of gateways and average MR-GW hop count, while achieving better load balance.

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 the traditional model for wireless mesh networks, a two-tiered architecture classifies nodes into mesh routers or clients. Such an approach, based on strong separation of roles, is interesting when an administrative entity deploys and controls the network. Nevertheless, in spontaneous and self-organized networks, where there is no administrative entity behind the network formation, this model does not hold anymore. In such a scenario the heterogeneity of nodes should be fully exploited in order to increase, as much as possible, network availability and usability. In this article we propose an approach for opportunistic wireless mesh network formation and maintenance that breaks the rigidness of the traditional architecture. We relax the role separation constraint and consider the case of spontaneous network formation relying on the concept of self-organization and collaboration. The main idea is to make the network take advantage of the specific resources and characteristics of the nodes in an opportunistic fashion. In our vision, any node (routers and clients) can perform any network functionality, if they can and if they wish.

A multi-radio Wireless Mesh Network (WMN) is a multi-hop network that consists of mesh routers and mesh clients, where mesh routers are equipped with multiple radio interfaces and form the backbone of the mesh network. To provide backbone support, it is necessary to reduce interference and balance load in Wireless Mesh Networks (WMNs). We propose load-aware routing metric (LARM), which captures the difference in transmission rates, packet loss ratio, intra/inter-flow interference and traffic load in multi-radio mesh networks. The LARM metric helps finding paths that are better in terms of balancing load and reducing the inter-flow and intra-flow interference in multi-radio networks. Simulation results show that LARM metric significantly outperforms several existing routing metrics in multi-radio wireless mesh networks.

A wireless mesh network (WMN) comprises of mesh access points (MAPs), mesh routers and mesh clients (MCs), where MAPs are almost static and form the back-bone of WMNs. MCs are wireless devices and dynamic in nature, communicating among themselves over possibly multi-hop paths, with or without the help of MAPs. Security has been a primary concern in order to provide protected communication in WMNs due to the open peer-to-peer network topology, shared wireless medium, stringent resource constraints and highly dynamic environment. These challenges clearly make a case for building multi-layer security solution that achieves both broad protection and desirable network performance. In this paper, we propose a cross-layer secure protocol for routing, data exchange and ARP problems (in case of LAN based upon WMNs). Our protocol is a ticket-based ad hoc on demand distance vector (TAODV) protocol, a secure routing protocol that is based on the design of ad hoc on demand distance vector (AODV) protocol. Due to availability of the backbone, we incorporate the authentication server (AS) for the issuance of tickets which are further used for secure routing, transfer of public keys and MAC addresses in one single step. With the transfer of public keys, source and destination can easily generate their shared secret key based upon fixed Diffie-Hellman key exchange protocol for data encryption and decryption. Our protocol is secure against both active and passive attacks.

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 placement of mesh routers (MRs) in building a wireless mesh network (WMN) is the first step to ensure the desired network performance. Given a network domain, the fundamental issue in placing MRs is to find the minimal configuration of MRs so as to satisfy the network coverage, connectivity, and Internet traffic demand. In this paper, the problem is addressed under a constraint network model in which the traffic demand is non-uniformly distributed and the candidate positions for MRs are pre-decided. After formulating the MR placement problem, we first provide the theoretical analysis to validate the traffic demand and determine the optimal position of Internet gateway (IGW). To reduce complexity of determining the locations of MRs while satisfying the traffic constraint, we propose an effective heuristic algorithm to obtain an close-to-optimal solution. Finally, our simulation results verify our analytical model and show the effectiveness of our proposed algorithm.

The continuous growth in user demand for high-quality rich media services puts pressure on Wireless Mesh Network (WMN) resources. Solutions such as those which increase the capacity of the mesh network by equipping mesh routers with additional wireless interfaces provide better Quality of Service (QoS) for video deliveries, but result in higher overall energy consumption for the network. This paper presents LBIS, a distributed solution which combines the benefits of both load-balancing and interface-shifting in order to enhance QoS levels for video services delivered over multi-hop WMNs, while maintaining low energy consumption levels within the network. Simulation-based results show very good performance of our proposed mechanism in terms of QoS metrics (delay, packet loss), Peak Signal-to-Noise Ratio (PSNR) and energy consumption in mesh network topologies, and with varying video traffic loads and distributions. The results demonstrate how LBIS can increase the QoS for video deliveries by more than 30% at the cost of an insignificant increase of the overall network energy consumption compared to the WMN with multiple radio interfaces without the LBIS adaptation.