认知Mesh网络的动态分层图路由模型及路由策略

该文提出了在认知无线电Mesh网络环境下的动态分层图路由模型,该模型将节点感知范围内的信道可用性用两状态离散时间马尔可夫链建模,建立认知无线电Mesh网络拓扑和连通性的动态模型。基于该模型提出了一种跨层设计的动态接口分配方案。仿真结果表明,动态分层图模型在适应接入频谱的动态变化和描述认知无线电Mesh网络的拓扑结构方面,表现出比静态分层图模型更加优异的性能。     

基于模糊推理的认知无线Mesh网络路由算法

认知无线Mesh网络中的节点能动态接入空闲频谱,然而,频谱空穴的频繁变化将导致网络路径的破坏,使得网络性能下降.提出了基于模糊推理的认知无线Mesh网络路由算法,该算法利用模糊Petri网的推理机制计算可行路径的可靠度,最终选择可靠度最高的路径和信道.仿真结果表明,认知无线Mesh网络使用推理机制的路由算法能够增加所选路由的可靠度,减少网络路径破坏数,提高网络吞吐量.     

无线Mesh网络服务质量保障技术综述

首先简要地介绍了无线Mesh网络的基本概况以及无线Mesh网络QoS保障技术的必要性和重要意义。然后,详细地讨论了无线Mesh网络的物理层、MAC层和路由层QoS保障技术以及跨层QoS设计技术的研究现状。最后,指出今后的研究难点与研究方向。     

基于认知无线电技术的动态频谱接入

文章介绍了基于认知无线电的动态频谱接入技术,并对其网络架构、关键技术以及目前的研究现状进行了详细分析。在此基础上探讨了动态频谱接入网络中采用跨层协议设计方法的必要性。     

无线Mesh网络QoS保障技术综述

首先,简要回顾了无线Mesh网络的基本概况,分析了在无线Mesh网络中提供QoS保障的必要性和重要意义。然后,系统地介绍了无线Mesh网络的物理层、MAC层和路由层QoS保障技术以及跨层QoS设计技术的国内外研究现状,对其进行了细致而科学的分类。最后,给出了它们的研究难点和研究方向。     

一种基于跨层的无线Mesh网络路由协议

无线Mesh网络的很多技术特点和优势来自于Mesh多跳路由.因此,路由协议的研究与设计是无线Mesh网络技术的一个重要课题.由于无线Mesh网络有自身负载均衡、路由容错与网络容量等要求,因此运用跨层设计,采用更好的路由参数,使用多径路由等方法已经成为无线Mesh网络路由协议设计的重要思路.根据无线Mesh的网络特点,按照其路由协议的设计要求,分析了路由协议DSR在Mesh网络中的不足,引入跨层设计的方法,提出了采用路由质量路径帧投递率(PFDR)为路由准则,并具有负载平衡、拥塞避免的路由协议CMRP.分析和仿真结果表明,CMRP在保持Mesh网络自身优点的同时,比起DSR在网络性能上有了较大的提升,在吞吐率方面有了很大的提高,相应的时延、抖动参数均有了大幅的下降,更加适用于无线Mesh网络.     

基于无线Mesh网络跨层协议研究

介绍无线Mesh网络的基本概念和特点,基于Mesh网络的相关MAC协议和路由协议,从物理层、MAC层、路由协议层等层面介绍WMN跨层设计的一般原则和方法,对WMN的跨层设计方法和方案进行了阐述,对目前Mesh网络中的传统OSI分层结构参考模型存在的问题进行了分析,提出需要进一步研究的问题。     

无线Mesh网络跨层优化及其安全机制研究

新兴的无线Mesh网络作为无线宽带接入网具有巨大的应用价值。基于最新无线通信技术标准,结合无线Mesh网络的特点,以网络性能及资源最大化利用为优化目标,提出对无线Mesh网络中物理层、媒体接入/数据链层、网络层各层间进行联合优化,并对无线Mesh网络相关的网络安全机制架构关键技术进行前瞻性的应用基础研究,为无线Mesh网络的组网与应用提供理论支持和技术保障。     

多跳认知无线Mesh网络中频谱决策与路由的跨层设计

灵活高效的频谱共享技术能够实现频谱资源的最大化利用,有效地缓解了无线频谱紧缺的现状。在一个与TDMA/FDMA蜂窝网络共存的多跳认知无线Mesh网络环境下,基于覆盖式（Underlay）与机会式（Overlay）相结合的频谱共享机制,提出了一种有效的链路层频谱决策与网络层路由的跨层设计方案。仿真结果表明,该方案比基于最小跳数的随机信道选择算法在网络端到端传输性能上有显著的优势。     

认知无线Mesh网络中基于马氏决策模型的MAC协议

为解决认知无线Mesh网络中专用控制信道较难获得的问题,提出一种基于POMDP的机会式频谱接入MAC协议,在不需要中心控制器和专用控制信道的协调下,实现动态频谱感知和接入。仿真结果表明,基于POMDP的接入策略能够有效提高网络频谱利用率和吞吐量,性能最优,而基于贪心算法的接入策略,在降低计算复杂度的同时,获得了较好的性能,实用性较强。     

Enhanced performance based on cross-layer design from physical to transport layers for multihop wireless networks

This paper puts forward a novel cognitive cross-layer design algorithms for multihop wireless networks optimization across physical,mediam access control(MAC),network and transport layers.As is well known,the conventional layered-protocol architecture can not provide optimal performance for wireless networks,and cross-layer design is becoming increasingly important for improving the performance of wireless networks.In this study,we formulate a specific network utility maximization(NUM)problem that we believe is appropriate for multihop wireless networks.By using the dual algorithm,the NUM problem has been optimal decomposed and solved with a novel distributed cross-layer design algorithm from physical to transport layers.Our solution enjoys the benefits of cross-layer optimization while maintaining the simplicity and modularity of the traditional layered architecture.The proposed cross-layer design can guarantee the end-to-end goals of data flows while fully utilizing network resources.Computer simulations have evaluated an enhanced performance of the proposed algorithm at both average source rate and network throughput.Meanwhile,the proposed algorithm has low implementation complexity for practical reality.     

Multipacket reception in random access wireless networks: fromsignal processing to optimal medium access control

There has been considerable interest in the idea of cross-layer design of wireless networks. This is motivated by the need to provide a greater level of adaptivity to variations of wireless channels. This article examines one aspect of the interaction between the physical and medium access control layers. In particular, we consider the impact of signal processing techniques that enable multipacket reception on the throughput and design of random access protocols     

A New Systematic Framework for Autonomous Cross-Layer Optimization

Cross-layer optimization solutions have been proposed in recent years to improve the performance of wireless users that operate in a time-varying, error-prone network environment. However, these solutions often rely on centralized cross-layer optimization solutions that violate the layered network architecture of the protocol stack by requiring layers to provide access to their internal protocol parameters to other layers. This paper presents a new systematic framework for cross-layer optimization, which allows each layer to make autonomous decisions to maximize the wireless user's utility by optimally determining what information should be exchanged among layers. Hence, this cross-layer framework preserves the current layered network architecture. Since the user interacts with the wireless environment at various layers of the protocol stack, the cross-layer optimization problem is solved in a layered fashion such that each layer adapts its own protocol parameters and exchanges information (messages) with other layers that cooperatively maximize the performance of the wireless user. Based on the proposed layered framework, we also design a message-exchange mechanism that determines the optimal cross-layer transmission strategies, given the user's experienced environment dynamics.     

移动栅格网中跨层资源管理方法研究

移动栅格网是一种全移动多跳无线栅格网络,采用了面向服务的全IP技术体制和全新的分层协议模型。针对这种新型网络结构和协议模型,提出了一种跨层资源管理方法,通过将呼叫接纳控制、路由选择、资源预留、排队机制以及信道接入机制等进行跨层设计,增加层间协作机制和方法以达到资源利用的优化和业务服务质量的提高。对跨层资源管理的总体框架和思路进行了详细描述,对具体实现途径进行了探讨。     

无线Mesh网络跨层路由技术研究

无线Mesh网络(WMN:wireless mesh networks)作为一种新型的无线网络,成为近几年研究的热点。由于无线信道不稳定等特性,如何设计WMN的路由协议成为决定其性能的关键因素之一。近几年来的研究表明,通过跨层设计的方式综合其他层的重要参数来实现路由选择,能够很好地解决这一难题。介绍了几种先进的跨层路由设计方案,总结了现有的跨层路由协议的优缺点,并对如何设计并实现跨层路由协议进行了分析和总结。     

仿真研究无线多跳网络跨层协议设计的优劣

为了改善无线多跳网络的性能，很多研究表明跨层协议设计比OSI模型更适合无线网络。本文分析了无线多跳网络的特征及对各协议层的影响，给出了跨层协议设计对网络性能的改善以及它可能带来的问题，并针对速率自适应MAC协议和网络层路由协议之间的相互影响给出了仿真实例，结果证明跨层协议设计要充分考虑不同协议之间的相互影响，合理规划、谨慎实施，否则网络的性能不升反降。     

A cautionary perspective on cross-layer design

Recently, in an effort to improve the performance of wireless networks, there has been increased interest in protocols that rely on interactions between different layers. However, such cross-layer design can run at cross purposes with sound and longer-term architectural principles, and lead to various negative consequences. This motivates us to step back and reexamine holistically the issue of cross-layer design and its architectural ramifications. We contend that a good architectural design leads to proliferation and longevity, and illustrate this with some historical examples. Even though the wireless medium is fundamentally different from the wired one, and can offer undreamt of modalities of cooperation, we show that the conventional layered architecture is a reasonable way to operate wireless networks, and is in fact optimal up to an order. However the temptation and perhaps even the need to optimize by incorporating cross-layer adaptation cannot be ignored, so we examine the issues involved. We show that unintended cross-layer interactions can have undesirable consequences on overall system performance. We illustrate them by certain cross-layer schemes loosely based on recent proposals. We attempt to distill a few general principles for cross-layer design. Moreover, unbridled cross-layer design can lead to spaghetti design, which can stifle further innovation and be difficult to upkeep. At a critical time when wireless networks may be on the cusp of massive proliferation, the architectural considerations may be paramount. We argue that it behooves us to exercise caution while engaging in cross-layer design.     

Cross-layer resource allocation for integrated Voice/Data traffic in wireless cellular networks

A major task in next-generation wireless cellular networks is provisioning of quality of service (QoS) over the bandwidth limited and error-prone wireless link. In this paper, we propose a cross-layer design scheme to provide QoS for voice and data traffic in wireless cellular networks with differentiated services (DiffServ) backbone. The scheme combines the transport layer protocols and link layer resource allocation to both guarantee the QoS requirements in the transport layer and achieve efficient resource utilization in the link layer. Optimal resource allocation problems for voice and data flows are formulated to guarantee pre-specified QoS with minimal required resources. For integrated voice/data traffic in a cell, a hybrid time-division/code-division medium access control (MAC) scheme is presented to achieve efficient multiplexing. Theoretical analysis and simulation results demonstrate the effectiveness of the proposed cross-layer approach.     

下一代无线网络中的跨层设计

下一代无线通信系统必须能够与互联网实现信息交互,这就需要利用通信协议来实现系统与其他通信系统间的互连互通。但是,现有通信协议基于OSI标准,其协议栈按照严格的分层方式工作,很难适应快速变化的无线通信环境。通过对现有协议栈进行改进,加入跨层设计方案则有助于改善下一代无线系统性能。文章简要分析了分层协议栈局限性,讨论了跨层设计原理,并系统地阐述了跨层设计时物理层、链路层、网络层、传输层和应用层协议应考虑的因素。