Performance Of Wireless Mesh Networks Research Articles

Dynamic routing algorithm in wireless mesh network

Wireless mesh networks (WMNs) have attracted increasing attention and deployment as a high-performance and low-cost solution to last-mile broadband internet access. WMNs have been broadly accepted in the conventional application sectors of ad hoc networks because of their advantages over other wireless networks. Traffic routing has a critical role in determining the performance of wireless mesh networks. Routing protocol design for wireless mesh networks is critical to maintain the performance and reliability of wireless mesh networks. Thus a routing protocol or an algorithm for WMNs should be carefully designed taking into account the specific characteristics of that network. Traditional routing protocols send traffic along pre-determined paths and have been shown ineffective in coping with unreliable and unpredictable wireless medium. In this paper we propose to formulate the mesh network routing problem as an optimisation problem. In the formulation of the problem we have considered both the static and dynamic traffic demand. This paper proposes a dynamic routing algorithm that is able to provide the optimal performance on all possible traffic demands. Our simulation results show that the proposed method performs competitively.

Mesh node placement in wireless mesh network based on multiobjective evolutionary metaheuristic

To achieve important properties of wireless mesh networks (WMNs) such as coverage and reliability, the placement of mesh nodes plays an important role. The impact of the mesh node placement on the performance of WMNs has been carried out in the past years. To improve such properties, we propose a novel scheme for mesh node placement in WMNs. We have developed a multi-objective optimisation model for node placement where the coverage, reliability and the total installation cost in terms of nodes to be deployed are the three objectives to optimise simultaneously. We first applied the two well-known evolutionary algorithms, namely the non-dominated sorting genetic algorithm-II (NSGA-II) and multi-objective genetic algorithm (MOGA) to generate the number and positions of the communication nodes. Subsequently, we developed algorithms that determine the cluster formation, gateway selection and relay nodes selection. The results showed satisfactory performance.

Qualitative Study of Existing Research Techniques on Wireless Mesh Network

Wireless Mesh Network (WMN) is one of the significant forms of the wireless mesh network that assists in creating highly interconnected communication node. Since a decade, there have been various studies towards enhancing the performance of WMN which is successful to a large extent. However, with the upcoming technology of pervasive and dynamic networks WMN suffers from various routing issues, Quality-of-Service (QoS) issue, channel allocation, sustainability of routes which makes the theory contradicting when considering for real-world challenges in wireless networks. This paper, therefore, brief about fundamental information of WMN followed by a discussion of existing research trends and existing research techniques. Finally, the paper also discusses the open research issues after reviewing the existing research techniques.

Joint Traffic Splitting, Rate Control, Routing, and Scheduling Algorithm for Maximizing Network Utility in Wireless Mesh Networks

The existence of multiple gateways, as is a common case in wireless mesh networks (WMNs), brings the possibility to improve network performance. However, previous studies, including both heuristic-based works and theory-driven cross-layer design works, cannot guarantee an optimal exploitation of multiple gateways. In this paper, we focus on exploiting multiple gateways optimally to achieve maximum network utility. We first extend the current framework of cross-layer design and formulate a network utility maximization (NUM) problem under WMNs with multiple gateways as a constrained optimization problem. Then, by solving this optimization problem, we propose a novel joint traffic splitting, rate control, routing, and scheduling algorithm called cross-layer control with dynamic gateway selection (CLC_DGS), which splits and distributes network traffic into multiple gateways in an optimal way. We prove that CLC_DGS can achieve maximum network utility. Finally, we run extensive simulations to demonstrate that, compared with the previous methods, CLC_DGS significantly improves the performance of WMNs under various network environments, including gateway heterogeneity, link heterogeneity, and different interference models.

Distributed Dynamic Memetic Algorithm Based Coding Aware Routing for Wireless Mesh Sensor Networks

Network coding has been confirmed as a potential technology to improve performance of wireless mesh networks (WMNs); network coding has great advantages for sensor networks like minimization of communication needed to collect sensor data and error recovery. A few network coding aware routings have been proposed. However, these mechanisms detect coding opportunities through local traffic pattern checking, which hardly obtains optimal routes. This paper proposes a Distributed Dynamic Memetic Algorithm Based Coding Aware Routing (DDMCAR) for wireless mesh networks, which employs memetic algorithm to optimize routes and coding opportunities. This paper proposes an improvement over GCAR algorithm by employing memetic algorithm and also meme sharing among nodes to increase the chance of finding optimal solution and continuous monitoring and update of meme fitness to achieve a dynamic tracking of network conditions, and finally using most fit memes for load balancing elevating congestion. Through simulations on randomly generated wireless mesh networks, DDMCAR is to be shown to find optimal routes within a short time and achieve more improvements than GCAR.

Source-Based Routing in Wireless Mesh Networks

Wireless mesh networks (WMNs) are currently used to provide broadband access to the Internet anytime and anywhere. Generally, WMNs consist of mesh routers equipped with one or more interfaces allowing connectivity to the Internet through gateways. To route traffic from sources to destinations, many routing protocols have been proposed in the literature. However, most of them take into account at most one metric (e.g., interferences, packet losses, and load at gateways). Moreover, almost all of these schemes consider only one type of interferences: interflow or intraflow. In this paper, we propose a new source routing and gateway selection scheme, which is called source-based routing (SBR), that improves the performance of WMNs. SBR uses a novel routing metric, which is a combination of packet losses, intraflow and interflow interferences, and load at gateways, to select best paths to reach selected gateways. Simulation results show that the proposed SBR improves the network performance and outperforms existing routing schemes, which are based on expected transmission count (ETX), nearest gateway (NG; i.e., shortest path to gateway), load at gateways (LG), or interference ratio (IR); more specifically, SBR yields 33%, 26%, 13%, and 10% more throughput compared with LG, ETX, NG, and IR, respectively.

Hybrid Genetic Optimization to Mitigate Starvation in Wireless Mesh Networks

Background/Objectives: The objective of this work is to mitigate starvation in Wireless Mesh Networks (WMNs) being deployed in today’s LAN, WAN and Internet topologies by employing a novel optimization method. Methods/Analysis: The QoS performance of WMNs is severely affected by a problem called starvation where nodes that are one-hop away from the gateway monopolize the channel so that far away nodes get starved of channel access. We propose a hybrid genetic algorithmic approach to mitigate starvation in WMNs by dynamic adjustment of contention window of mesh nodes optimally. In this approach, Genetic Algorithm incorporated with Gravitational Search Algorithm is used. Findings: Simulations are conducted using the proposed method for multimedia traffic with AODV as the routing protocol. The performance of the proposed method is compared with priority-based method, pure GA optimization, Fair Binary Exponential Back-off algorithm (FBEB) and IEEE 802.11. The local search capability of GSA incorporated in our proposed method improves the throughput by 24.64% than priority-based method and by 3.56% than pure GA optimization. In our approach, we observed a significant decrease in end-to-end delay compared to pure GA optimization. Improvement in fairness is found along one-hop, two-hop and three-hop nodes when compared with FBEB. The FBEB algorithm adjusts the CW size by indirectly estimating the traffic in communication medium leading to lesser throughput whereas our proposed method changes the CW size dynamically based on QoS parameters of network nodes leading to improvement in throughput. The proposed method increases throughput by 5.10% than IEEE 802.11 and by 1.25% than FBEB at one-hop. The proposed method increases throughput by 66.67% than IEEE 802.11 and by 22.61% than FBEB at two-hop. Application/Improvement: Our hybrid Genetic optimization method improves QoS performance of Wireless Mesh networks by avoiding throughput imbalances among users and reducing end-to-end delay effectively. Keywords: Contention Window, Genetic Algorithm, Gravitational Search Algorithm, Starvation, Wireless Mesh Networks

Research on gateway deployment of WMN based on maximum coupling subgraph and PSO algorithm

The maximum distance from the access points to the nearest gateways determines the network time delay, and has an important effect on network performance in wireless mesh networks. Motivated by the gateway deployment problem, this study is focused on optimizing the gateway deployment by minimizing the maximum distance. This is done by first improving upon theorems so that the plane can be divided into several intersecting regions; vertices locate in the same region are equivalent and can connect the same access points; the coordinates of the regions can also be determined. Then, maximum coupling subgraph is used in order to recognize the maximum intersecting regions; meanwhile, the coordinates are calculated by representative points. Lastly, an RPSO algorithm is designed in which representative points are taken as the initial particles to search the optimal gateway deployment. The simulation results demonstrate that the optimal gateway deployment, as determined by the RPSO algorithm process, has a smaller coverage radius, a more stable result and a faster convergence rate as compared to other algorithms.

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.

A Review of Routing Protocols for Practical Rural Wireless Mesh Networks (WMNs)

The flexibility of WMNs affords their usage to provide broadband and communications services in many environments including rural domains. Routing protocols are central to the design of rural networks to ensure data availability and efficient performance especially under dynamic conditions of resource-constrained rural areas. In this paper, we review four routing protocols utilized for rural deployments namely AODV, OLSR, OSPF and BATMAN vis-a-vis the most critical metrics for rural requirements. Specifically, the comparative analysis shows the need for an objective evaluation of protocols for rural WMN scenarios. We also noted that metrics such as protocol overhead, convergence time and topology control remains critical for the performance of rural WMNs. Consequently, we argue that an objective performance evaluation offers a reliable selection criterion regarding the most efficient routing protocol when deploying WMNs. The study will further conduct simulation experiments to advocate the modification and synthesis of reliable protocols that will meet varying stringent requirements of remote settings.

End-to-End Route Reliability in Pervasive Multi-Channel Multi-Radio (PMCMR) Scheme for MANETS

Multi-channel multi radio wireless communications technologies have changed the trend of traditional routing based Quality of Service (QoS) in wireless-mesh networks. This avalanche of growth in multimedia communication is trigged by Multi-Channel Multi-Radio Wireless Mesh Networks (MCMR-WMNs). It is forecasted that in the near future, societal networks will have latest state of the art radio devices with Multi Channel and Multi Radio (MCMR) communication power with enhanced reliability, throughput and self-healing features. Despite of marked improvements in data link layer and physical layer in the IEEE 802.11 standards, optimized throughput, performance and network availability of MCMR wireless mesh networks still depend upon the efficient routing metric or protocol. We carried out a set of experiment and observed that cross layer routing in mesh networks is highly influenced by traffic load, interference between channel and interference between nodes. Proposed scheme used ‘conjugate distribution method’ which was designed to evaluate end-to-end route and communication reliability using posterior distribution function. Routing metric is evaluated based on load aware, intra and inter-interface aware, packet average delivery ration, latency and overhead with considered criteria of average path length. Competitive study revealed that proposed technique is efficient and applicable especial in environment where end-to-end reliability is required.

Modified Greedy Physical Link Scheduling Algorithm for Improving Wireless Mesh Network Performance

The algorithm to allocate mesh active link to radio resource timeslot in wireless mesh network (WMN) is investigated. This paper proposes the novel method to allocate multiple links in one timeslot for improving the wireless mesh network throughput via spatial time division multiple access (STDMA) protocol. The throughput improvement is obtained by modifying greedy based algorithm that is widely known as a low complexity algorithm. We propose and investigate new parameters in the greedy based algorithm that can be used as scheduling control parameters, i.e. interference weight, scheduling weight, and the sum of link’s degree. Simulation results indicate that this approximation increases network performance in throughput and length of scheduling performance closed to the upper bound performance that is achieved by the algorithm that uses the physical interference model.

Dominating Set and Network Coding-Based Routing in Wireless Mesh Networks

Wireless mesh networks are widely applied in many fields such as industrial controlling, environmental monitoring, and military operations. Network coding is promising technology that can improve the performance of wireless mesh networks. In particular, network coding is suitable for wireless mesh networks as the fixed backbone of wireless mesh is usually unlimited energy. However, coding collision is a severe problem affecting network performance. To avoid this, routing should be effectively designed with an optimum combination of coding opportunity and coding validity. In this paper, we propose a Connected Dominating Set (CDS)-based and Flow-oriented Coding-aware Routing (CFCR) mechanism to actively increase potential coding opportunities. Our work provides two major contributions. First, it effectively deals with the coding collision problem of flows by introducing the information conformation process, which effectively decreases the failure rate of decoding. Secondly, our routing process considers the benefit of CDS and flow coding simultaneously. Through formalized analysis of the routing parameters, CFCR can choose optimized routing with reliable transmission and small cost. Our evaluation shows CFCR has a lower packet loss ratio and higher throughput than existing methods, such as Adaptive Control of Packet Overhead in XOR Network Coding (ACPO), or Distributed Coding-Aware Routing (DCAR).

Combining Local Channel Selection with Routing Metrics in Multi-channel Wireless Mesh Networks

Dynamic metric is a well-known method to improve performance of WMNs (Wireless Mesh Networks). By quantifying quality of links, and by computing optimal paths based on the values, dynamic metrics enable packets to be forwarded with high-quality links while avoiding low-quality links. ETX [1] would be the best-known dynamic metric, which measures the average retransmission count on a link via periodically transmitted probe packets. Many dynamic metrics have been proposed so far, which include those for multi-channel WMNs such as WCETT [2] and MIC [3]. They proved that dynamic metrics improve network performance in multi-channel environments by pursuing relatively slow transition of link quality.

Performance evaluation of AOMDV routing algorithm with local repair for wireless mesh networks

Recently, wireless mesh networks (WMNs) technology has gained a lot of attention in network research community. WMN is a multi-hop wireless access network where nodes can act both as a router as well as a host. One of the factors that influence the performance of WMNs is the underlying routing protocol used. Thus, numbers of different multipath routing protocols are proposed in recent years. This paper addresses the requirement of local repair under high speed movement scene of wireless mesh network, of route breakage in multipath routing in wireless mesh networks. In this context we have proposed a local repair based AOMDV protocol, to maximize the benefit of proposed algorithm to achieve better performance metrics in both packet loss ratio and routing overhead and packet delivery ratio in high speed mobility networks. Various simulations with varying nodes has been conducted to validate the improvement of the proposed algorithm against the original AOMDV. Performance comparison between AOMDV and AOMDVLR has been analysed in detail, showing that proposed AOMDVLR has achieved better outcome in certain scenarios.

Solving mesh router nodes placement problem in Wireless Mesh Networks by Tabu Search algorithm

Wireless Mesh Networks (WMNs) are an important networking paradigm that offer cost effective Internet connectivity. The performance and operability of WMNs depend, among other factors, on the placement of network nodes in the area. Among the most important objectives in designing a WMN is the formation of a mesh backbone to achieve high user coverage. Given a number of router nodes to deploy, a deployment area and positions of client nodes in the area, an optimization problem can be formulated aiming to find the placement of router nodes so as to maximize network connectivity and user coverage. This optimization problem belongs to facility location problems, which are computationally hard to solve to optimality. In this paper we present the implementation and evaluation of Tabu Search (TS) for the problem of mesh router node placement in WMNs. The experimental evaluation showed the efficiency of TS in solving a benchmark of instances.

A location coordinate-based video delivery scheme over wireless mesh networks

In this mobile-centric era, users expect ubiquitous access at low cost to an ever increasing range of applications requiring increasingly high data connection speeds. Wireless Mesh Network (WMN) technology provides support for data access over a relatively large area at a modest cost while also being easy and flexible to deploy. Unfortunately, WMN performance is sensitive to load, and applications such as video on demand are likely to stress the network. In response to this, approaches to balance traffic load, such as peer-to-peer solutions are very promising. However, in order to work efficiently, these solutions require not only availability awareness, but also knowledge about location of peers and services. This paper presents a wireless coordinate-based location-aware overlay mechanism for locating and retrieving requested video segments from the nearest peers in order to improve retrieved video quality in WMN. In comparison to the original overlay schemes, our mechanism has significant benefits in both overlay communication efficiency and data retrieval efficiency. Simulation results in both regular and random video segment placement scenarios show how the proposed peer-to-peer video delivery solution for WMN outperforms existing state-of-the-art solutions in terms of video quality and packet loss with different background traffic loads and replication rates.

ALLEVIATE EXPOSED NODE ISSUES IN WIRELESS MESH NETWORK (WMN) USING A NOVEL APPROACH OF CONCURRENT MEDIUM ACCESS CONTROL (C-MAC) PROTOCOL

The importance and high growth of the communication infrastructure is clearly stated under the Malaysia Economic Transformation Programme (ETP). The most popular technology that used to provide the internet service to public is the IEEE 802.11a/b/g/n based WiFi. However, the coverage provided by the WiFi technology is only limited up to certain range. In addition, the performance of the WiFi network also will become poorer and poorer as the number of users associate with that WiFi network increases. In order to address these issues, the best topology configuration known as mesh is proposed by wireless research community. This technology is also called as Wireless Mesh Networks (WMN) and it became an emerging technology which is plays an important role in the next generation wireless communication. However, the implementation of IEEE 802.11 Medium Access Control (MAC) protocol in WMN significantly degrades the network performance due to the presence of exposed node problem. The presence of exposed nodes in WMN caused waiting delay (prevent the surrounding neighboring nodes to involve in transmission activity for entire duration of ongoing transmission) and it is subsequently leads to poor throughput achievement. The significance of this research is to investigate the cause of exposed nodes that degrade the performance of WMN and proposed a novel protocol to solve it to provide better network performance and throughput.

GaS: A Gateway Scheduling-Based Beamforming Scheme for Handoff Support in Wireless Mesh Networks

Fast handoff support is a basic requirement for an Internet-based wireless mesh network (WMN), aiming to guarantee mobile users continuous connection to the Internet, regardless of their physical locations or moving trajectory. Due to the multihop transmission of network-layer handoff signaling packets, handoff performance in WMNs can be largely degraded by the increasing number of wireless hops as well as the channel access contentions between data and signaling packets in the mesh backbone. However, these issues are ignored in existing handoff solutions and multichannel medium-access control schemes. In this paper, we address the seamless handoff support from a different perspective and propose a gateway scheduling-based (GaS) beamforming scheme for handoff support in single-radio multichannel multihop WMNs. Our proposed beamforming scheme can realize single-hop handoff signaling packet transmissions and eliminate the channel contentions between data and signaling packets. Simulation results show that the total handoff delay is significantly improved using our proposed GaS beamforming scheme under various scenarios, as compared with existing handoff solutions in multihop WMNs. In addition, due to the single-hop transmission of signaling packets, the signaling overhead in the wireless mesh backbone can be substantially reduced.

Fairness-oriented routing algorithm joint with power control and channel assignment for multi-radio multi-channel wireless mesh networks

The multi-radio multi-channel wireless mesh network (MRMC-WMN) draws general attention because of its excellent throughput performance, robustness and relative low cost. The closed interactions among power control (PC), channel assignment (CA) and routing is contributed to the performance of multi-radio multi-channel wireless mesh networks (MRMC-WMNs). However, the joint PC, CA and routing (JPCR) design, desired to achieve a global optimization, was poor addressed. The authors present a routing algorithm joint with PC and CA (JPCRA) to seek the routing, power and channel scheme for each flow, which can improve the fairness performance. Firstly, considering available channels and power levels, the routing metric, called minimum flow rate, is designed based on the physical interference and Shannon channel models. The JPCRA is presented based on the genetic algorithm (GA) with simulated annealing to maximize the minimum flow rate, an non-deterministic polynomial-time hard (NP-Hard) problem. Simulations show the JPCRA obtains better fairness among different flows and higher network throughput.