Measures of region failure survivability for wireless mesh networks

Wireless Networks - Wireless mesh networks (WMNs) are considered as a promising alternative to wired local, or metropolitan area networks. However, owing to their exposure to various disruptive...     

Load aware adaptive backbone synthesis in Wireless Mesh Networks

Wireless Mesh Networks (WMNs) are envisioned to support the wired backbone with a wireless Backbone Networks (BNet) for providing internet connectivity to large-scale areas.With a wide range of internet-oriented applications with different Quality of Service (QoS) requirement,the large-scale WMNs should have good scalability and large bandwidth.In this paper,a Load Aware Adaptive Backbone Synthesis (LAABS) algorithm is proposed to automatically balance the traffic flow in the WMNs.The BNet will dynamically split into smaller size or merge into bigger one according to statistic load information of Backbone Nodes (BNs).Simulation results show LAABS generates moderate BNet size and converges quickly,thus providing scalable and stable BNet to facilitate traffic flow.     

On the fairness of resource allocation in wireless mesh networks: a survey

This article presents a comprehensive survey of resource allocation techniques in Wireless Mesh Networks (WMNs). Wireless mesh networks have emerged as a key technology for next generation application specific multi-hop wireless networks. We analyze the state-of-the-art resource allocation schemes for WMNs, providing comprehensive taxonomy of the latest work and the future research trends in this field. In general, the resources that are available for WMNs include time, frequency, space, relays, and power. An efficient utilization of these resources can make the network more robust, reliable, and fair. We categorize the resource allocation into “radio” resource allocation, “physical” resource allocation, “utility” based resource optimization, and “cross layer” resource optimization. An ample review of resource allocation schemes within these categories is provided.     

Multi-virtual wireless mesh networks through multiple channels and interfaces

Wireless Networks - The high flexibility of the wireless mesh networks (WMNs) physical infrastructure can be exploited to provide communication with different technologies and support for a variety...     

网络编码在无线Mesh网络中的研究与实现

Mesh网络沿用了Ad Hoc网络中的路由协议,但Mesh网络节点移动性高,路径的生存周期短,根据无线Mesh网络自身的动态特点进行路由协议的优化成为了研究的热点。COPE编码方案是针对Mesh网络中的单播特性提出的一种新的机会网络编码机制,能够提高网络的吞吐量。通过NS2仿真平台对AODV路由协议添加COPE网络编码方案,仿真结果表明在不同网络条件下,AODV和COPE的结合增加了无线节点的编码机会,使网络的吞吐量得到了有效的提高。     

无线网状网技术与应用

无线网状网(WMNs)由网状路由器节点和客户机节点组成,其中的网状路由器节点组成了无线网状网的网络骨干,其移动性很小。他们一起为无线网状网和其他常规无线网络的客户机节点提供网络的无线接入。WMNs技术结合了中心式控制的蜂窝网与分布式控制的无线自组织网的优点,可有效克服这两种技术的缺陷并显著提高无线网络的性能,已经成为下一代无线通信网络的研究热点之一。WMNs可为无线个域网、局域网、校园网、城域网的一系列应用提供高速无线宽带接入服务。虽然目前WMNs技术发展很快,但其协议栈各层仍存在许多有待研究的课题。首先简要介绍了无线网状网的结构与特点;随后重点分析了其主要的几个应用领域;最后探讨了WMNs各协议层的研究现状与关键技术,并分析了该技术存在的问题及未来的研究方向。     

基于MAODV无线Mesh网多播路由协议的优化

针对无线Mesh网(WMNs)现有的路由协议不能很好地解决多播视频业务对时延的要求,以Ad hoc网络中多播路由协议MAODV为基础,结合无线网络拓扑的动态变化,在WMN下提出一种基于路径优化的ROMAODV(Routing Optimization-MAODV)路由算法.此算法以很小的优化开销获得延时的大幅度减小,仿...     

基于启发式WCA的WMNs多网关选址方法

为了保证可扩展性,分簇是设计无线网格网(WMNs)的必然选择,而多网关选址是分簇规划的核心。分析了WMNs多网关选址的服务质量(QoS)约束条件,以及现有方法的缺陷,提出了一种基于启发式加权分簇算法(WCA)的WMNs多网关选址方法。在节点数量不是非常多的情况下,还提出可以采用基于布尔代数的最优化方法进行WMNs多网关选址,该方法可以提高网络的鲁棒性。算法仿真表明,本文提出的方法取得了良好的效果。     

Wireless Cooperative Mesh Network:A New Architecture for Network Convergence

The convergence of heterogeneous wireless networks is a trend in the evolution of wireless networks.A new architecture for network convergence,named Wireless Cooperative Mesh Network,is proposed to solve such emerging problems in convergence as transmission mode selection,load balancing,routing and handover.The new architecture is based on the structure of Wireless Mesh Networks (WMNs),and cooperative communication is also employed to further optimize its structure and upgrade its performance.It can thus obtain advantages of both the Mesh technology (high spectrum efficiency and dynamic self-organization) and cooperative communication (high diversity gain and high energy efficiency).The new architecture serves as an efficient solution for wireless network convergence.     

A Role Based Privacy-Aware Secure Routing Protocol for Wireless Mesh Networks

Wireless Mesh Networks (WMNs) have drawn much attention for emerging as a promising technology to meet the challenges in next generation networks. Security and privacy protection have been the primary concerns in pushing towards the success of WMNs. There have been a multitude of solutions proposed to ensure the security of the routing protocol and the privacy information in WMNs. However, most of them are based on the assumptions that all nodes cooperate with routing and forwarding packets and the attacks are from outside. In order to defend against the internal attacks and to achieve better security and privacy protection, this paper proposes a role based privacy-aware secure routing protocol (RPASRP), which combines a new dynamic reputation mechanism with the role based multi-level security technology and a hierarchical key management protocol. Simulation results show that RPASRP implements the security and privacy protection against the inside attacks more effectively and efficiently and performs better than the classical hybrid wireless mesh protocol in terms of packet delivery ratio and average route length.     

CLEAR: A Cross-Layer Enhanced and Adaptive Routing Framework for Wireless Mesh Networks

Wireless Mesh Networks (WMNs) provide a new and promising solution for broadband Internet services. The distinguishing features and the wide range of WMNs’ applications have attracted both academic and industrial communities. Routing protocols play a crucial role in the functionality and the performance of WMNs due to their direct effect on network throughput, connectivity, supported Quality of Service (QoS) levels, etc. In this paper, a cross-layer based routing framework for multi-interface/multi-channel WMNs, called Cross-Layer Enhanced and Adaptive Routing (CLEAR), is proposed. This framework embodies optimal as well as heuristic solutions. The major component of CLEAR is a new bio-inspired routing protocol called Birds’ Migration Routing protocol (BMR). BMR adopts a newly developed routing metric called Multi-Level Routing metric (MLR) to efficiently utilize the advantages of both multi-radio/multi-channel WMNs and cross-layer design. We also provide an exact solution based on dynamic programming to solve the optimal routing problem in WMNs. Simulation results show that our framework outperforms other routing schemes in terms of network throughput, end-to-end delay, and interference reduction, in addition to being the closest one to the optimal solution.     

Context-based wireless mesh networks: a case for network virtualization

Wireless Mesh Networks (WMNs) have gained increasing attention as an attractive means to provide connectivity in complement to access as offered by regular Internet Service Providers (ISPs). Such a grass-root technique, however, often suffers from detrimental operating conditions and poor quality. Network virtualization, on the other hand, has been widely advocated as a possibility to overcome what has often been referred to as the ossification of the Internet. Combining the concept of network virtualization with WMN technology, therefore, appears to be promising and desirable. It is envisioned that well managed multiple Virtual Networks (VNs) may overcome shortcomings of WMNs on the one hand, and extend the reach of the Internet beyond its current confinement into the realm and control of the user on the other hand. In this paper, we argue for a context-based approach for an effective means to extend multi-VNs from the Internet domain into WMN environments. We describe both mobility and preferences as context models in order to create virtualized WMNs based on these types of context models. As a result, it is envisioned to achieve a comprehensive connectivity coverage, accompanied by high assurance in network quality. We further present a distributed solution to manage multi-VNs, and a mobility-aware context use case to demonstrate the usefulness of our approach.     

基于排队模型的无线Mesh网延时分析与优化

在提供无线接入的网格网中,不同用户因所处地理位置的不同所获得的服务质量（吞吐量、延时）会有较大程度的差异。文中使用排队网络对Mesh网建立模型,从理论上分析了非饱和流量的情况下不同用户获得的延时的差异。分析发现,通过设置多个缓冲区并调度不同数据流在中间节点上的优先级别,可以使不同用户的延时趋于均匀从而保证网络的公平性。把优先级的分配问题归结为一个以公平性为目标的组合优化问题并提供了解法。使用Lorenz曲线来度量公平性,仿真结果表明,使用优化的调度算法可以获得更好的网络公平性。     

Design and analysis of intrusion detection systems for wireless mesh networks

Intrusion is any unwanted activity that can disrupt the normal functions of wired or wireless networks. Wireless mesh networking technology has been pivotal in providing an affordable means to deploy a network and allow omnipresent access to users on the Internet. A multitude of emerging public services rely on the widespread, high-speed, and inexpensive connectivity provided by such networks. The absence of a centralized network infrastructure and open shared medium makes WMNs particularly susceptible to malevolent attacks, especially in multihop networks. Hence, it is becoming increasingly important to ensure privacy, security, and resilience when designing such networks. An effective method to detect possible internal and external attack vectors is to use an intrusion detection system. Although many Intrusion Detection Systems (IDSs) were proposed for Wireless Mesh Networks (WMNs), they can only detect intrusions in a particular layer. Because WMNs are vulnerable to multilayer security attacks, a cross-layer IDS are required to detect and respond to such attacks. In this study, we analyzed cross-layer IDS options in WMN environments. The main objective was to understand how such schemes detect security attacks at several OSI layers. The suggested IDS is verified in many scenarios, and the experimental results show its efficiency.     

适合机会路由的低复杂度分布式信道分配

Opportunistic Routing (OR) involves mul-tiple forwarding candidates to relay packets by tak-ing advantage of the broadcast nature and multi-us-er diversity of a wireless medium. Compared with Traditional Routing (TR), OR is more suitable in the case of an unreliable wireless link and can evidently improve the end-to-end throughput of Wireless Mesh Networks (WMNs). In this paper, we focus on OR in Multi-Radio Multi-Channel WMNs (MRMC-WMNs). This problem has not been well examined and is considerably more challenging than the OR in single-radio wireless networks considered in the existing literature. First, we validate the advantage of OR in MRMC-WMNs. Second, we propose Low-complexity Channel Assignment for Opportunistic Routing ( LcCAOR ), which assigns channels to flows according to the interference state of every node. Third, we implement the LcCOAR in a fully distributed manner. The simulation result shows that compared with OR in Single-Radio Single-Channel WMNs (SRSC-WMNs), the proposed OR can sig-nificantly enhance the throughput to 87. 11% and 100.3% in grid and tree WMNs, respectively.     

Scalability Technologies for Wireless Mesh Networks

The continuous increase of data transmission density in wireless mobile communications has posed a challenge to the system performance of Wireless Mesh Networks (WMNs ). There is a rule for wireless Ad hoc networks that the average node capacity decreases while the number of nodes increases , so it is hard to establish a large - scale wireless Mesh network. Network scalability is very important for enhancing the adaptive networking capability of the wireless Mesh network. This article discusses key scalability technologies for Mesh Base Stations (BSs ) and Mesh Mobile Stations (MSs ), such as channel allocation, intelligent routing , multi- antenna , node classification, Quality of Service (QoS) differentiation and cooperative transmission.     

基于网络利用率最大化来提高无线Mesh网络中TCP协议的传输性能

In Wireless Mesh Networks (WMNs), the performance of conventional TCP significantly deteriorates due to the unreliable wireless channel. To enhance TCP performance in WMNs, TCP/LT is proposed in this paper. It introduces fountain codes into packet reorganization in the protocol stack of mesh gateways and mesh clients. Furthermore, it is compatible with conventional TCP. Regarded as a Performance Enhancement Proxies (PEP), a mesh gateway buffers TCP packets into several blocks. It simultaneously processes them by using fountain encoders and then sends them to mesh clients. Apart from the improvement of the throughput of a unitary TCP flow, the entire network utility maximization can also be ensured by adjusting the scale of coding blocks for each TCP flow adaptively. Simulations show that TCP/LT presents high throughput gains over single TCP in lossy links of WMNs while preserving the fairness for multiple TCPs. As losses increase, the transmission delay of TCP/LT experiences a slow linear growth in contrast to the exponential growth of TCP.     

Achieving seamless handoffs via backhaul support in Wireless Mesh Networks

In Wireless Mesh Networks (WMNs), mobile clients may experience frequent handoffs due to the relatively small transmission range of the mesh routers. Each handoff may lead to packet delays and/or packet losses, which limits the performance of real-time applications over WMNs. In this work, we propose BASH—a Backhaul-Aided Seamless Handoff scheme. BASH takes advantage of the wireless backhaul feature of WMNs, and allows a mobile station to directly access the backhaul channel to probe the neighboring mesh routers. Our work shows that by utilizing the wireless backhaul, BASH (1) reduces the probing latency and, thus, the Layer-2 handoff latency; (2) allows partial overlap of the Layer-2 and Layer-3 handoffs, reducing the overall handoff latency; and (3) shortens the authentication latency by utilizing the transitivity of trust relationship. The experimental results show that BASH achieves an average Layer-2 handoff of 8.9 ms, which supports real-time applications during the handoff.     

Enhanced Active Queue Management for Multi-hop Networks

Wireless networks play a very important role in today’s modern world, convincingly surpassing the wired infrastructure in terms of popularity. Hence, it is important to ensure that services which access wired networks should also be accessible using a wireless network without any performance degradation. One of the most common variants in wireless communications is the Wireless Mesh Network (WMNs). WMNs exploit multi-hop wireless communications between wireless access points. Hence, the effective bandwidth decreases as the number of hops increases in a WMN, thus increasing latency and resulting in reduced performance. This may be due to spatial contention, multipath fading, interference or inefficient queuing mechanisms etc. Here we take queuing mechanisms into consideration and study the QMMN algorithm (Queue Management for Multi-hop Networks) which tends to improve throughput, fairness and reduce global synchronization problems. Based on our study, we implement a modified version of the QMMN algorithm, otherwise called the Enhanced QMMN (EQMMN) algorithm. EQMMN can be considered an effective algorithm which solves the problem of fairness between flows (either responsive or unresponsive) and eventually improves TCP throughput at wireless access points. Our experimental results prove that EQMMN algorithms have better performance characteristics such as throughput (TCP) and fairness index compared to QMMN algorithms.     

Throughput Gateways-Congestion Trade-Off in Designing Multi-Radio Wireless Networks

In Wireless Mesh Networks (WMNs), traffic is mainly routed by WMN Backbone (WMNB) between the mesh clients and the Internet and goes through mesh gateways. Since almost all traffic has to pass through one of the MGs, the network may be unexpectedly congested at one or more of them, even if every mesh router provides enough throughput capacity. In this paper, we address the problem of congestion of gateways while designing WMNs. We propose a simultaneous optimization of three competing objectives, namely network deployment cost, interference between network channels and congestion of gateways while guaranteeing full coverage for mesh clients. We tailor a nature inspired meta-heuristic algorithm to solve the model whereby, several trade-off solutions are provided to the network planner to choose from. A comparative experimental study with different key parameter settings is conducted to evaluate the performance of the model.