基于多业务QoS服务的拓扑控制算法研究

随着无线网络技术的不断发展,无线Ad hoc网络中,快速变化的网络拓扑影响着网络的性能。因此,在实现网络能量优化的前提下,如何提供有效的QoS服务来满足多业务要求是无线Ad hoc网络所必须面对的问题。针对此问题,提出了一种基于多业务需求的拓扑控制的方法,该方法考虑业务QoS指标的同时引入跨层的设计思想,实现了跨层的功率控制,减少了网络中节点的能量消耗,延长了网络的生命周期。     

Ad Hoc网络中跨层QoS保障方法的研究

跨层设计方法是一种新近推出的系统优化技术,非常适合于为Ad Hoc网络中的业务提供QoS保障。文章全面分析了Ad Hoc网络中的跨层QoS保障策略和方法,介绍了2种基于跨层设计理念的QoS体系结构,并详细探讨了适用于Ad Hoc网络的跨层QoS模型。同时,指出了未来的研究工作。     

浅析无线局域网QoS机制

无线局域网(WLAN)技术的发展带来的多媒体业务流量的剧增,使无线网络的资源管理、服务质量(QoS)保障等问题日益突出。传统的媒体访问控制(MAC)协议需要重新设计,才能使无线网络的QoS问题得到有效的解决。本文介绍了无限局域网QoS技术的发展,包括针对IEEE 802.11MAC层协议进行的各种QoS增强技术。通过与传统802.11标准的MAC层进行对比分析,讨论了IEEE 802.lle的两个新的策略:增强的分布式协调功能和混合协调功能。     

无线网络跨层技术及展望

跨层设计是提高无线网络综合性能的一种解决方案.文章针对跨层反馈原理,分析无线网络跨层设计方法,并概括基当前应用、存在的问题,最后预测基应用前景.     

无线网络跨层设计的研究现状及展望

跨层设计是提高无线网络综合性能的一种解决方案。文章针对无线网络的特点,介绍跨层设计思想,分析无线网络跨层设计的设计方法步骤,并概括其当前应用、存在的问题,最后预测其应用前景。     

无线传感器网络跨层优化研究

无线传感器网络系统的跨层优化理论在当前是一个研究热点.在传统的无线网络设计中,一般是沿用有线网络的设计思想,特别是利用因特网的设计思想来设计无线网络.然而由于无线传感器具有网络资源和能量受限的特点,这就使得传统的有线网络中分层设计的思想遇到了未曾预计的尴尬与挑战.本文对无线传感器网络中的跨层优化工作原理进行了叙述,比较了各个跨层优化技术的特点.最后阐述了当前跨层设计技术面临的挑战.     

无线网络跨层技术及展望

跨层设计是提高无线网络综合性能的一种解决方案。文章针对跨层反馈原理，分析无线网络跨层设计方法，并概括其当前应用、存在的问题，最后预测其应用前景。     

无线网络中带有补偿机制的跨层调度算法

随着人们对各种无线网络要求的增加,单纯的对一层进行调度显然已经无法满足当今的要求.于是,我们从跨层的观点出发,以提高系统吞吐量和公平性为前提,提出了一种带有补偿机制的跨层调度算法.该算法采用了跨层调度的思想,将自适应调制技术结合到其中,在保证用户基本QoS的前提下,对由于信道状况不好而丧失发送机会的分组进行适当的补偿,...     

无线Ad Hoc网络中支持P2P应用的研究

无线Ad Hoc网络和P2P技术近年来发展迅速,已经成为宽带无线网络技术领域的研究热点.相关研究表明.在现有的无线Ad Hoc网络中直接应用P2P技术.会造成系统开销大量增加,分组传输效率及查询成功率下降,从而影响整个网络的性能.本文针对上述问题进行分析,采用跨层设计的方法,提出了在无线Ad Hoc网络中实现P2P应用的解决思路和方案,满足无线Ad Hoc网络中各种P2P应用的不同QoS需求.     

UWB无线网络QoS跨层联合优化的研究

为了更好地实现无线办公室组网,无线家庭组网,必须对UWB无线网络的QoS进行优化.对UWB无线网络MAC协议--IEEE 802.15.3进行了分析,介绍了基于跨层设计的DCC-MAC算法.在NS2.29环境下进行了仿真,测试表明:即使节点数增多,干扰增强,采用DCC-MAC协议的UWB无线网络能保持比较高的平均吞吐量,当节点的总个数从2到60变化时,系统吞吐量约为250Mbit/s.     

Cross-Layer Design for QoS Support in Multihop Wireless Networks

Due to such features as low cost, ease of deployment, increased coverage, and enhanced capacity, multihop wireless networks such as ad hoc networks, mesh networks, and sensor networks that form the network in a self-organized manner without relying on fixed infrastructure is touted as the new frontier of wireless networking. Providing efficient quality of service (QoS) support is essential for such networks, as they need to deliver real-time services like video, audio, and voice over IP besides the traditional data service. Various solutions have been proposed to provide soft QoS over multihop wireless networks from different layers in the network protocol stack. However, the layered concept was primarily created for wired networks, and multihop wireless networks oppose strict layered design because of their dynamic nature, infrastructureless architecture, and time-varying unstable links and topology. The concept of cross-layer design is based on architecture where different layers can exchange information in order to improve the overall network performance. Promising results achieved by cross-layer optimizations initiated significant research activity in this area. This paper aims to review the present study on the cross-layer paradigm for QoS support in multihop wireless networks. Several examples of evolutionary and revolutionary cross-layer approaches are presented in detail. Realizing the new trends for wireless networking, such as cooperative communication and networking, opportunistic transmission, real system performance evaluation, etc., several open issues related to cross-layer design for QoS support over multihop wireless networks are also discussed in the paper.     

Cross-layer resource allocation over wireless relay networks for quality of service provisioning

The authors propose a physical-datalink cross-layer resource allocation scheme over wireless relay networks for quality-of-service (QoS) guarantees. By integrating information theory with the concept of effective capacity, the proposed scheme aims at maximizing the relay network throughput subject to a given delay QoS constraint. This delay constraint is characterized by the so-called QoS exponent thetas, which is the only requested information exchanged between the physical layer and the datalink layer in our cross-layer design based scheme. Over both amplify-and-forwards (AF) and decode-and-forward (DF) relay networks; the authors develop the associated dynamic resource allocation algorithms for wireless multimedia communications. Over DF relay network, the authors also study a fixed power allocation scheme to provide QoS guarantees. The simulations and numerical results verify that our proposed cross-layer resource allocation can efficiently support diverse QoS requirements over wireless relay networks. Both AF and DF relays show significant superiorities over direct transmissions when the delay QoS constraints are stringent. On the other hand, the results demonstrate the importance of deploying the dynamic resource allocation for stringent delay QoS guarantees.     

认知无线Mesh网络跨层设计研究

传统网络的分层设计不能满足具有特殊QoS需求的无线宽带业务,无法应对动态频谱接入的无线通信环境。采用联合开放、架构灵活的跨层设计研究无线Mesh网络接入技术日渐成为热点。本文首先介绍了跨层设计的起源、分类,然后分析了认知无线Mesh网络跨层研究的挑战、难点及最新进展,并提出利用跨层设计实现路由及频谱管理的一种构想,最后展望了认知无线Mesh网络跨层研究的新方向。     

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.     

Cross-Layer Optimized Conditions for QoS Support in Multi-Hop Wireless Networks with MIMO Links

Recent advances in antenna technology made it possible to build wireless devices with more than one antenna at affordable costs. Because multiple antennas offer wireless networks a potential capacity increase, they are expected to be a key part of next-generation wireless networks to support the rapidly emerging multimedia applications characterized by their high and diverse QoS requirements. This paper developed methods that exploit the benefits of multiple antennas to enable multi-hop wireless networks with flow-level QoS capabilities. The authors first propose a cross-layer table-driven statistical approach that allows each node to determine the amount of spatial reuse and/or multiplexing, offered by the multiple antennas that are available to it. The authors then use the developed statistical approach to derive sufficient conditions under which flow rates are guaranteed to be feasible. The derived conditions are multi-layer aware in the sense that they account for cross-layer effects between the PHY and the MAC layers to support QoS at higher layers. The authors evaluate and compare the derived sufficient conditions via extensive simulations. The authors show that the conditions result in high flow acceptance rates when used in multi-hop wireless networking problems such as QoS routing and multicommodity flow problems. The authors also demonstrate the importance and the effect of considering cross-layer couplings into the development of flow acceptance methods.     

无线Ad Hoc网络中的QoS路由协议

无线Ad Hoc网络的应用环境以及与Internet的互连都要求其必须提供一定的服务质量(QoS)保证,QoS路由技术是在无线Ad Hoc网络中实现QoS的重要方法。本文对近年来国内外在无线Ad Hoc网络中的QoS路由技术方面取得的研究成果进行了全面的概括总结和分类,对资源预留路由、多径路由和跨层优化路由3类QoS路由协议进行比较分析,并且提出了QoS路由技术亟待解决的问题和今后的发展方向。     

基于动态规划法的无线Mesh网络QoS路由算法和性能评价

该文针对时延敏感的多媒体业务吞吐率和传输可靠性的考虑,在无线Mesh网络中,引入动态规划和跨层设计方法设计QoS路由算法。在假设的网络模型上,提出了一个新的基于MAC层信息的综合凸规划路由准则,以及基于此实现的路由算法CPRMQS,详细给出了利用动态规划法解决路由优化问题的算法流程和样例分析。最后通过仿真验证了该算法的可行性,并给出了基于DSR扩展协议的性能评价,其中包括吞吐率和延时等性能。     

Asymptotic loss of real-time traffic in wireless mobile networks with selective-repeat ARQ

We study the issue of quality of service (QoS) for real-time traffic over a wireless channel deploying automatic repeat request (ARQ) error control. An analytical model has been derived to evaluate the queueing related loss and the wireless channel related loss. In contrast to previous work, this model quantifies the interaction between the network layer and the physical layer, and then it enables the admission controllers of wireless networks to improve utilization while satisfying the traffic QoS constraints through cross-layer design techniques.     

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。