Gateway placement optimization for load balancing in wireless mesh networks

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.

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 (WMN), mesh clients (MCs) access the Internet through the wireless backbone formed by the Mesh Routers (MRs) and Internet Gateways (IGWs). Internet Gateways are the traffic center in each IGW service domain thus may also become the congestion center. To improve the performance of a WMN, the load balancing between different IGW service domains is investigated. The load fairness between IGWs domains will improve the network performance and provides a better quality of service (QoS) for end users. In this paper, the fairness index is defined for both homogenous and heterogeneous WMNs. A probabilistic load balancing algorithm based on the simulated annealing method is proposed to get the global load fairness.

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 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.

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.

In this paper, we present a hybrid intelligent simulation system for optimization of mesh routers in Wireless Mesh Networks (WMNs) called WMN-PSOHCDGA. We implemented six mesh router replacement methods: CM, RIWM, LDIWM, LDVM, RDVM and FC-RDVM and consider Two Islands distribution of mesh clients. We carry out a comparison study of these router replacement methods for small and middle scale WMNs. We assessed the performance by computer simulations. The simulation results show that six methods have a good performance for connectivity and coverage metrics, for both small and middle scale WMNs. However, they have different behavior for load balancing. For small scale WMNs, the load balancing of LDIWM, RIWM and FC-RDVM is better than CM, LDVM and RDVM. While, comparing LDIWM, RIWM and FC-RDVM, the LDIWM has better load balancing. We found that the load balancing for small scale WMNs is not good, because there is a concentration of mesh routers in some areas. For middle scale WMNs, the CM, LDIWM, LDVM and RDVM have not a good load balancing. While, the RIWM and FC-RDVM have better performance. Comparing RIWM and FC-RDVM, we found that the load balancing of FC-RDVM is better than RIWM.

Wireless Mesh Network (WMN) is emerging as key technology for the next generation network due to its features like providing broadband access with low cost and applicability to versatile areas. WMN's are basically multi-hop networks, in which data is forwarded to backbone through a gateway from the client nodes and vice versa. The client nodes may be wired or wireless and may be mobile with varying client network architecture. Gateway has fixed bandwidth to be shared by all the clients for communication. It causes reduction in per client throughput as the number of clients is increasing and thus may lead to overall performance degradation. Associating clients to gateway is a crucial point in deciding performance as is gateway placement, routing and scheduling at the gateway. Associating nodes to a single nearest gateway causes reduction in capacity of WMN and unfairness amongst the nodes. Clients can be associated to multiple gateways. WMN are dynamically self-organizing and self-healing and this imposes even more responsibility on gateways. Having multiple gateways in clustered WMN can improve performance significantly.

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.

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.

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.

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.

By the enormous increase in mobile nodes and diverse service requests on wireless networks, wireless mesh network(WMN) takes an interest as the solution for such requests. However, lots of issues which should be solved to deploy WMN are still remained. In the network layer, the performance improvement of routing protocols is the major issue of nowadays researches. WMN can be easily deployed by use of protocols for mobile ad-hoc networks(MANET) because it is much similar with MANET in multi-hop wireless routing and which node plays as host and router concurrently. Unfortunately, most routing protocols for MANET have drawbacks such as large traffic overhead and long delay time for route discovery due to the network extension. They are major factors of performance degradation of WMN and most researches are focused on them. In this paper, domain-based AODV which is amended AODV to be applied in hybrid WMN is proposed. The proposed scheme divides a hybrid WMN as several domains and performs route discovery by header layer domain. Therefore it can reduce the distance for route discovery as much as average hop count between domain header and member nodes. From the simulation, domain-based AODV was showed slowly increasing delay time due to the network extension.

In a wireless mesh network (WMN), the traffic is aggregated and forwarded towards the gateways. Strategically placing and connecting the gateways to the wired backbone is critical to the management and efficient operation of a WMN. In this paper, we address the problem of gateways placement, consisting in placing a minimum number of gateways such that quality-of-service (QoS) requirements are satisfied. We propose a polynomial time near-optimal algorithm which recursively computes minimum weighted Dominating Sets (DS), while consistently preserving QoS requirements across iterations. We evaluate the performance of our algorithm using both analysis and simulation, and show that it outperforms other alternative schemes by comparing the number of gateways placed in different scenarios

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.