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针对现有的无线Mesh网络多信道分配算法无法解决煤矿应急救援中无线Mesh网络因传输干扰导致的信道分配抖动问题,结合无线Mesh网络连通性以及干扰模型,提出了一种基于拓扑分层和干扰避免的多信道分配算法,即对网络拓扑分层,在确定第1层节点与边的基础上,继续对其他层进行拓扑分配,然后根据干扰情况对各层进行信道分配。设计了仿真模型:无线Mesh节点发射距离为200m,干扰距离为500m,拓扑范围为1 000m×1 000m。随机选取20个节点,在可用信道变化和网关变化2种情况下对该算法进行仿真分析,结果表明该算法较常用的拓扑结构算法提高了网络的吞吐量,降低了信道分配中的传输干扰。 相似文献
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无线Mesh网(WMN)是一种新型宽带无线接入技术,选择适当的MAC子层规范,根据网络业务特征有效地配置信道资源,可以提高Mesh网的无线资源使用效率以及系统传输性能。而现有的无线Mesh网络基本上是采用单信道MAC协议,不能满足日益俱增的用户需求,限制了整个网络的数据传输速率与网络容量。文中基于忙音多址访问的设计思想,结合无线Mesh网络的特点,提出了一种无线Mesh网MAC协议MCBTMA(Multi-Channel Busy Tone Multiple Access)。MCBTMA通过构建多个忙信号控制信道和多个数据信道,在MAC层进行多信道调度,使无线Mesh网络在吞吐量和时延方面性能有显著提高。 相似文献
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无线Mesh网(WMN)是一种新犁宽带无线接入技术,选择适当的MAC子层规范,根据网络业务特征有效地配置信道资源,可以提高Mesh网的无线资源使用效率以及系统传输性能.而现有的无线Mesh网络基本上是采用单信道MAC协议,不能满足日益俱增的用户需求,限制了整个网络的数据传输速率与网络容量.文中基于忙音多址访问的设计思想,结合无线Mesh网络的特点,提出了一种无线Mesh网MAC协议MCBTMA(Multi-Channel Busy Tone Multiple Access).MCBTMA通过构建多个忙信号控制信道和多个数据信道,在MAC层进行多信道调度,使无线Mesh网络在吞吐量和时延方面性能有显著提高. 相似文献
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针对多网卡多信道无线Mesh网络容量问题,基于无线信道干扰模型,在给定各节点物理层发射功率的条件下,联合考虑无线Mesh网络传输层的流速控制、网络层的路由算法和MAC层的信道分配等问题,通过采用二次路由计算策略,提出了一个跨层联合优化算法,仿真结果表示,提出的算法能提高网络吞吐量。 相似文献
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针对无线Mesh网络中由于无线信号干扰而造成的端到端吞吐量并不理想问题,提出一种采用功率控制构造无线Mesh网络拓扑的算法,通过调整节点的传输功率到一个合理的水平来降低干扰以提高信道的空间复用度,从而改善网络的吞吐量。结合流量模型和干扰模型计算整个网络的吞吐量。仿真结果表明,该拓扑控制能够提高无线Mesh网络的吞吐量。 相似文献
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多信道多接口可以明显提高Mesh网络的吞吐量,然而已有的多信道分配算法和协议基本上都没有考虑无线信道的隔离度,这样便造成了路径间干扰。提出了一种基于信道隔离度的启发式多信道分配算法(CSCA),有效地减少了路径间干扰。所构建的森林拓扑一方面方便了信道分配,另一方面也改善了流量均衡。模拟实验结果表明,CSCA算法有效地降低了Mesh网络中的干扰,提高了网络吞吐量。 相似文献
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Lei Guo Yuhuai PengXingwei Wang Dingde JiangYinpeng Yu 《Computers & Electrical Engineering》2011,37(1):106-114
In wireless networks, users expect to get access to the network securely and seamlessly to share the data flow of access points anytime and anywhere. However, either point-to-point or point-to-multipoint methods in traditional wireless networks make the network bandwidth decrease rapidly, which cannot meet the requirements of users. Recently, a new wireless broadband access network, wireless mesh networks (WMNs), has emerged. As one of the key technologies in WMNs, wireless routing protocols plays an important role in performance optimization of WMNs. Therefore, in this paper, we address the on-demand routing protocols by focusing on dynamic source routing (DSR) protocol and ad hoc on-demand distance vector (AODV) routing protocol in WMNs. Then, we use the OPNET modules to establish the simulation models of DSR and AODV protocols in WMNs. Simulation and results show that, DSR protocol that is based on the dynamic source routing is not suitable for wireless transmission, while AODV routing protocol that is based on the purpose-driven routing is suitable for wireless transmission with rapid change of network topology. 相似文献
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Recent advances in wireless mesh networks (WMNs) have overcome the drawbacks of traditional wired networks and wireless ad hoc networks. WMNs will play a leading role in the next generation of networks, and the question of how to provide seamless mobility management for WMNs is the driving force behind the research. The inherent characteristics of WMNs, such as relatively static backbones and highly mobile clients, require new mobility management solutions to be designed and implemented.In this paper, a hybrid routing protocol for forwarding packets is proposed: this involves both link layer routing and network layer routing. Based on the hybrid routing protocol, a mobility management scheme for WMNs is presented. Both intra-domain and inter-domain mobility management have been designed to support seamless roaming in WiFi-based WMNs. During intra-domain handoff, gratuitous ARP messages are used to provide new routing information, thus avoiding re-routing and location update. For inter-domain handoff, redundant tunnels are removed in order to minimize forwarding latency. Comprehensive simulation results illustrate that our scheme has low packet latency, low packet loss ratio and short handoff latency. As a result, real-time applications over 802.11 WMNs such as VoIP can be supported. 相似文献
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The availability of bandwidth in wireless mesh networks (WMNs) introduces it as a prominent choice for implementing bandwidth sensitive services. Multicast services such as teleconferencing, push-based systems, multiplayer games, etc., can be implemented in an efficient way in such networks. Moreover, the severe performance degradations that can result from the interference generated by concurrent data transmissions and environmental noises call for the development of interference-aware routing mechanisms. This paper investigates the impact of wireless interference on network performance for multicast transmission in WMNs. We show that by taking wireless interference into consideration in the design of routing mechanisms, better resource usage can be achieved. Hence, a fuzzy logic–based approach is proposed to choose optimal routes from source to the multicast group in multichannel case. Three fuzzy variables are considered in route selection phase, which are interference, available bandwidth, and hop count. Extensive simulations are conducted aiming at verifying the high performance of the proposed algorithm. Simulation results demonstrated that our proposed algorithm outperforms Link-Controlled Multi-Rate Multi-Channel (LC-MRMC) and Channel Assignment with Multiple Factor (CAMF) algorithms in terms of throughput, packet delivery ratio, and end-to-end delay. 相似文献
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目前,无线网状网跨层路由设计方兴未艾,以往无线路由设计是基于最小跳数的,缺少对无线网状网特性的综合考虑,并不能充分发挥出无线网状网的优势。该文提出了基于"队列负载率"和"链路传输效率"的跨层路由协议算法,通过将MAC层的网络状态信息传递给网络层的路由代理,以便选择负载较小的最佳路由。通过仿真可以发现,改文提出的路由不仅显著提高了吞吐量,而且使包的投递更加可靠,提高了QoS。 相似文献
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Asad Amir Pirzada Marius Portmann Ryan Wishart Jadwiga Indulska 《Pervasive and Mobile Computing》2009,5(2):201-221
Reliable broadband communication is becoming increasingly important during disaster recovery and emergency response operations. In situations where infrastructure-based communication is not available or has been disrupted, an Incident Area Network needs to be dynamically deployed, i.e. a temporary network that provides communication services for efficient crisis management at an incident site. Wireless Mesh Networks (WMNs) are multi-hop wireless networks with self-healing and self-configuring capabilities. These features, combined with the ability to provide wireless broadband connectivity at a comparably low cost, make WMNs a promising technology for incident management communications. This paper specifically focuses on hybrid WMNs, which allow both mobile client devices as well as dedicated infrastructure nodes to form the network and provide routing and forwarding functionality. Hybrid WMNs are the most generic and most flexible type of mesh networks and are ideally suited to meet the requirements of incident area communications. However, current wireless mesh and ad-hoc routing protocols do not perform well in hybrid WMN, and are not able to establish stable and high throughput communication paths. One of the key reasons for this is their inability to exploit the typical high degree of heterogeneity in hybrid WMNs. SafeMesh, the routing protocol presented in this paper, addresses the limitations of current mesh and ad-hoc routing protocols in the context of hybrid WMNs. SafeMesh is based on the well-known AODV routing protocol, and implements a number of modifications and extensions that significantly improve its performance in hybrid WMNs. This is demonstrated via an extensive set of simulation results. We further show the practicality of the protocol through a prototype implementation and provide performance results obtained from a small-scale testbed deployment. 相似文献
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Sonia Waharte Raouf Boutaba Youssef Iraqi Brent Ishibashi 《Multimedia Tools and Applications》2006,29(3):285-303
Wireless Mesh Networks (WMNs) are an emerging technology that could revolutionize the way wireless network access is provided. The interconnection of access points using wireless links exhibits great potential in addressing the “last mile” connectivity issue. To realize this vision, it is imperative to provide efficient resource management. Resource management encompasses a number of different issues, including routing. Although a profusion of routing mechanisms has been proposed for other wireless networks, the unique characteristics of WMNs (e.g., wireless backbone) suggest that WMNs demand a specific solution. To have a clear and precise focus on future research in WMN routing, the characteristics of WMNs that have a strong impact on routing must be identified. Then a set of criteria is defined against which the existing routing protocols from ad hoc, sensor, and WMNs can be evaluated and performance metrics identified. This will serve as the basis for deriving the key design features for routing in wireless mesh networks. Thus, this paper will help to guide and refocus future works in this area.
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Brent IshibashiEmail: |
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Quality of service (QoS) provisioning in wireless mesh networks (WMNs) is an open issue to support emerging multimedia services. In this paper, we study the problem of QoS provisioning in terms of end-to-end bandwidth allocation in WMNs. It is challenging due to interferences in the networks. We consider widely used interference models and show that except a few special cases, the problem of finding a feasible path is NP-complete under the models. We propose a k-shortest path based algorithmic framework to solve this problem. We also consider the problem of optimizing network performance by on-line dynamic routing, and adapt commonly used conventional QoS routing metrics to be used in WMNs. We find the optimal solutions for these problems through formulating them as optimization models. A model is developed to check the existence of a feasible path and another to find the optimal path for a demand; moreover, an on-line optimal QoS routing algorithm is developed. Comparing the algorithms implemented by the proposed framework with the optimization models shows that our solution can find existing feasible paths with high probability, efficiently optimizes path lengths, and has a comparable performance to the optimal QoS routing algorithm. Furthermore, our results show that contrary to wireline networks, minimizing resource consumption should be preferred over load distribution even in lightly loaded WMNs. 相似文献
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Dimitrios KoutsonikolasAuthor Vitae Saumitra M. DasY. Charlie HuAuthor Vitae 《Journal of Parallel and Distributed Computing》2008
Multicast is a fundamental routing service in wireless mesh networks (WMNs) due to its many potential applications such as video conferencing, online games, and webcast. Recently, researchers proposed using link-quality-based routing metrics for finding high-throughput paths for multicast routing. However, the performance of such link-quality-based multicast routing is still limited by severe unfairness. Two major artifacts that exist in WMNs are fading which leads to low quality links, and interference which leads to unfair channel allocation in the 802.11 MAC protocol. These artifacts cause the multicast application to behave unfairly with respect to the performance achieved by the multicast receivers. 相似文献
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Raffaele BrunoAuthor Vitae Marco Conti Author VitaeAntonio Pinizzotto Author Vitae 《Performance Evaluation》2011,68(9):841-858
In practical wireless mesh networks (WMNs), gateways are subject to hard capacity limits on the aggregate number of flows (in terms of bit rate) that they can support. Thus, if traffic is routed in the mesh network without considering those constraints, as well as the traffic distribution, some gateways or intermediate mesh routers may rapidly get overloaded, and the network resources can be unevenly utilized. To address this problem, in this paper we firstly develop a multi-class queuing network model to analyze feasible throughput allocations, as well as average end-to-end delay, in heterogeneous WMNs. Guided by our analysis, we design a Capacity-Aware Route Selection algorithm (CARS), which allocates network paths to downstream and upstream Internet flows so as to ensure a more balanced utilization of wireless network resources and gateways’ fixed connections. Through simulations in a number of different network scenarios we show that the CARS scheme significantly outperforms conventional shortest path routing, as well as an alternative routing method that distributes the traffic load on the gateway nodes to minimize its variance. 相似文献