无线Mesh网络关键技术

无线Mesh网络(WMN)是一种特殊的Adhoc网络,具有分层的网络结构,其传输骨干网具有多跳、拓扑稳定、无供电约束、业务流量相对汇聚等特性。提高WMN频谱空间复用度是增加网络容量有效的方法,而其设计的关键是有效控制无线链路间的干扰范围。基于多信道的组网技术是WMN关键技术之一,其核心是信道的分配,通过合理的信道分配以获得最大信道利用率。WMN中路由度量的选取需要考虑多跳无线链路间的相互干扰,而通过采用负载均衡路由技术可以均衡网络资源的使用,从而提高网络容量和节点的吞吐率。     

Reliability Strategies for Data Transmission in Wireless Mesh Network

Wireless Mesh Network (WMN) is a new-type wireless network. Its core idea is that any of its wireless equipment can act as both an Access Point (AP) and a router. Each node in the network can send and receive signals as well as directly communicate with one or several peer nodes. One important issue to be considered in wireless Mesh networks is how to secure reliable data transmission in multi-hop links. To solve the problem, the 3GPP system architecture proposes two functionalities: ARQ and HARQ. This paper presents two HARQ schemes, namely hop-by-hop and edge-to-edge, and three ARQ schemes: hop-by-hop, edge-to-edge, and last-hop. Moreover, it proposes three solutions for WMNs from the perspective of protocol stock design: layered cooperative mechanism, relay ARQ mechanism and multi-hop mechanism.     

Key Technologies of Wireless Mesh Network

The Wireless Mesh Network (WMN) is a special kind of Ad hoc network with a hierarchical network structure . Its backbone transmission network has such characteristics as multi- hop , topology stability, no electricity supply constraints , convergence of flows . Improving the spatial reuse of spectrum is an effective approach to increase network capacity. The linchpin of this approach is to effectively control the interference range between wireless links . The multi- channel networking technology is one of the key technologies of WMN, and its core is the channel allocation through which the channel utilization can be maximized . The mutual interference between multi- hop wireless links should be considered when choosing the routing metrics in WMN. Through the load - balancing routing method , the network capacity and throughput of nodes can be improved .     

无线网状网中基于干扰模型的多信道分配策略

为解决信道干扰导致无线网状网吞吐量下降的问题,本文提出一种新的基于干扰模型的多信道分配策略.首先对网络进行分层,然后按照优先级逐层进行信道分配,通过降低信道间的干扰来提高每个结点的吞吐量,进而提高整个网络的吞吐量.仿真结果表明了该策略的有效性.     

A static/opportunistic hybrid-scheduling scheme for MIMO wireless networks

Multiple Input Multiple Output (MIMO) based Spatial Time Division Multiple Access (STDMA) Wireless Mesh Networks (WMNs) have attracted extensive research attention. However, there are two problems in existing studies: (1) the employed MIMO link rate models are not suitable for a MIMO link of a practical STDMA WMN, and (2) the designed scheduling algorithms usually cannot take advantage of the multi-user diversity in a WMN. In this paper, we develop an analytical model for determining the MIMO link rate of an STDMA WMN. Based on a node-based slot assignment and scheduling algorithm (Chen and Lea in IEEE Trans Veh Technol 62(1):272–283, 2013), we propose a static/opportunistic hybrid scheduling framework that can exploit multi-user diversity and channel fading. The performance evaluation shows that the proposed framework has 33–46 % throughput gain over the prior joint routing and time slot assignment schemes for MIMO WMNs.     

非饱和业务下帧聚合性能分析(英文)

This paper proposes an analysis model of frame aggregation in error-free channel with unsaturated traffic and fixed aggregation size. Integrated with model of channel access, calculation of MAC (Media Access Control) average service time and queue model of frame aggregation, our model can get the stable result with a recursive algorithm, and it further derive the throughput and latency of frame aggregation in steady state. As the impact of traffic, frame length, collision probability, buffer size, aggregati...     

基于无线Mesh网络技术构建无线城市

无线Mesh网络(WMN)可以和多种无线网络系统,如无线局域网(WLAN)、无线城域网(WMAN)等相结合,改善无线网络的性能,提高网络的覆盖范围.以WMN网络技术在IEEE 802系列标准中的发展为基础,提出了一种无线城市的覆盖方案,最底层网络覆盖采用WiFi+wireless Mesh技术,WiMAX网络与WiFi...     

Wireless Mesh Networks and Cooperative Relaying Technologies

The Wireless Mesh Network (WMN) has become a focus in research of wireless broadband communications . In a switching technologies - based wireless Mesh network, the entire network is regarded as an IP subnet, so it cannot be applied in situations where large coverage is required . The use of cooperative relaying technologies can improve the transmission rate and reliability of wireless link; while the wireless Mesh network, once integrated with cooperative relaying technologies and routing technologies , can improve its spectrum efficiency and cover a wide area . However, there are many problems to be solved with respect to standardization, key technologies research and industrialization. Therefore , the application of cooperative relaying technologies in wireless Mesh networks is still a great challenge .     

基于改进离散蝙蝠算法的无线Mesh网络部分重叠信道分配

针对应急通信背景下无线Mesh网络(WMN)中存在的信道干扰和频谱资源利用不充分的问题,该文提出一种改进的离散蝙蝠算法(IDBA)用于求解最优部分重叠信道(POCs)分配方案。该方法采用K-means聚类算法优化网络拓扑,引入樽海鞘群的链式行为提高局部搜索能力,建立以最小化链路加权干扰为目标的线性规划模型来解决流量汇聚情况可能造成的网络瓶颈链路问题。仿真结果表明,在不同网络规模下,相比于其他基于群智能优化算法的信道分配方法,该方法具有较快的收敛速度和较优的搜索能力。此外,该方法能够在节点密集时显著降低网络干扰并保持网络的稳定性。     

一种环境感知的无线Mesh网络自适应QoS路径选择算法

本文针对如何改善无线多跳Mesh网络的服务质量,满足无线多媒体业务对数据传输的带宽、时延、抖动的要求等问题,研究了一种基于无线信道状态和链路质量统计的MAC层最大重传次数的自适应调整算法。该算法通过对无线Mesh网络的无线信道环境的动态感知,利用分层判断法区分无线分组丢失的主要原因是无线差错还是网络拥塞导致,实时调整MAC层的最佳重传次数,降低无线网络中的分组冲突概率。基于链路状态信息的统计和最大重传策略,提出了一种启发式的基于环境感知的QoS路由优化机制HEAOR。该算法通过动态感知底层链路状态信息,利用灰色关联分析法自适应选择最优路径,在不增加系统复杂度的基础上,减少链路误判概率,提高传输效率。NS2仿真结果表明,HEAOR算法能有效减少重路由次数,降低链路失效概率,提高网络的平均吞吐率。本文提出的方法不仅能够优化MAC层的重传,而且通过发现跨层设计的优化参数实现对路径的优化选择。      

Multi-hop Delay Performance in Wireless Mesh Networks

Wireless Mesh Network (WMN) technology is an attractive solution to meet the demand of broadband network access anywhere and anytime. In order to effectively support delay-sensitive applications such as video streaming and interactive gaming in a WMN, it is crucial to develop feasible methodologies and techniques for accurately analyzing, predicting and guaranteeing end-to-end delay performance over multi-hop wireless communication paths. In this paper, we extend the link-layer effective capacity model and derive a lower bound of delay-bound violation probability, or complementary cumulative distribution function, over multi-hop wireless connections. A fluid traffic model with cross traffic and a Rayleigh fading channel with additive Gaussian noise and Doppler spectrum are considered in our study. The average multi-hop delay and jitter performance bounds are also obtained. Analytical results are verified by extensive computer simulations under different traffic load and wireless channel conditions. We find that multi-hop delay performance is much more sensitive to traffic load and maximum Doppler rate than traffic correlation.     

Wormhole-Free Routing and DoS Attack Defense in Wireless Mesh Networks

Owing to the growth in several applications, Wireless Mesh Networks (WMN) is emerging as a vital technology for future wireless networks. Wormhole attack is one of the major security threats, which can disturb majority of routing communications, even when placed strategically. Therefore, a technique that can find wormhole-free routes in the network is required. In order to achieve this, in this paper, we propose a Monitoring Technique for Wormhole-Free Routing and DoS Attack Defense in WMNs. Initially, finite state model is applied where the node keeps the information about its sender and neighborhood receiver. Then, wormhole-aware secure routing is implemented to find wormhole free routes in the network. Finally, the priority mechanism is applied where the data packets are transmitted based on their priority. Based on the finite state model and priority mechanism, the malicious or wormhole nodes in the network are removed.     

新一代无线Mesh网络

无线Mesh网络是下一代无线网络的关键技术之一,近几年得到了人们的广泛关注和快速发展.为了以低成本的代价实现无处不在的高速Intemet,新一代无线Mesh网络的发展势在必行.新一代无线Mesh网络旨在能够提供高性能和高可靠性的服务.本文介绍了传统无线Me8h网络的优缺点,分析了研究现状,并阐诛了新一代无线Mesh网络面临的技术挑战.     

Wireless Mesh Technology and Network

Wireless Mesh Network (WMN) has been actively researched and developed as a new network technology to support broadband high- speed multimedia services . This paper discusses WMN technology and applications , and introduces the basic technologies , typical applications and current development of the WMN. With the future development of wireless distribution technology and network, wireless Mesh technology and network will become the key networking technology and architecture of wireless mobile communications , and will be widely used in various wireless networks with more important roles .     

Wireless Mesh Network and IEEE 802 Standards

Although the wireless broadband access system is developing rapidly, its development is limited due to some disadvantages , such as small capacity of bandwidth and small coverage . The Wireless Mesh Network (WMN) is one of the important technologies for "last mile "broadband wireless access . The WMN can integrate with multiple wireless systems , such as Wireless Local Area Network (WLAN), Wireless Personal Area Network (WPAN), and Wireless Metropolitan Area Network (WMAN), to improve the performance of the wireless network and enlarge the coverage range . With the wide applications of the WMN, the IEEE 802 standard group is devoted to promoting the development of the WMN technology and establishing the related technical standards . At present, WMN standards have appeared in IEEE 802.11s , 802.15, 802.16, and 802.20.     

无线Mesh网络与IEEE802系列标准

无线宽带接入系统发展迅速,但带宽容量低、覆盖范围小等缺点限制了它的进一步发展。作为“最后一公里”宽带无线接入非常重要的技术之一。无线Mesh网络（WMN）可以和多种无线网络系统,如无线局域网（WLAN）、无线个域网（WPAN）以及无线城域网（WMAN）等相结合,改善无线网络的性能,提高网络的覆盖范围。随着无线Mesh网络技术的厂泛应用,IEEE802的相关标准组正在致力于推动WMN技术的发展,制订相关的技术标准。目前,WMN标准已经出现在IEEE802．11s、80215、802．16、802．20中。     

无线Mesh网络时延分析模型

无线Mesh网络由于拓扑结构、Mac协议、路由协议以及信道分配策略的复杂多变,其系统平均时延分析一直没有得到很好的解决。提出了一种基于排队论的时延分析模型,分析了在任意拓扑结构和路由协议下,处于基础工作模式的无线Mesh网络平均时延,并同时考虑了多收发器、多信道的影响。计算机仿真结果表明该模型能够比较准确的估计出网络性能,可以为无线Mesh网络部署以及优化提供理论依据。     

Key Technology and Experimental Research in Wireless Mesh Networks

With the increasing popularity and rising demand for high-rate wireless Internet access, traditional wireless access networks such as cellular network and Wireless Local Area Network (WLAN) are facing some challenges. The Wireless Mesh Network (WMN) is emerging as a flexible and low-cost alternative to provide multi-hop communications, supporting applications such as last-mile Internet delivery. The WMN has also become a promising technology in the merging of wireless networks. Some key technologies for the WMN networking, including network configuration, power control, mobility management, access control, and routing protocols, are analyzed; the routing protocol design in WMN and mobile Ad hoc network are compared. An example of WMN testbed based on WLAN and second-layer switching technology is given.     

无线Mesh技术和网络

无线网状网（WMN）是近年被高度重视和快速发展的新型网络技术,支持宽带高速多媒体业务服务。文章就无线Mesh网络技术和应用进行讨论,综述无线Mesh网络的发展由来、基本技术、典型应用和现在的发展。随着未来无线分布技术和无线分布网络的发展,无线Mesh技术和网络将会成为无线移动通信的基本网络技术和网络结构,渗透到各种无线网络中,发挥更大作用。     

无线网状网组网技术及实验研究

面对日益增长的高速无线因特网接入需求,传统的无线接入方式,如蜂窝网、无线局域网（WLAN）面临许多挑战,而无线网状网（WMN）作为因特网“最后一公里”接入方案,提供一种灵活而低成本的多跳通信,也将成为各种无线网络融合的主要技术。针对这一极具发展前途的网络结构,从WMN的两种典型应用出发,文章从网络配置、功率控制、移动性管理和接入控制以及路由协议设计等方面说明了WMN组网中的相关问题和技术,对WMN与移动自组织（Ad hoc）网路由协议的设计进行了对比,并给出了一种基于WLAN和第二层交换技术的WMN试验床实现方案。