无线宽带网络及其演进策略

首先回顾了无线宽带网络的发展状况,因特网和移动通信都以极高的速度普及和增长,并为构建未来的无线宽带网络奠定了基础。介绍了当前的研究热点,包括WLAN、3G、4G、AdHoc等,对它们的特点进行了比较,分析了各自在未来网络融合中所起的作用。指出了无线宽带网络发展是一个循序渐进的过程,介绍了通过网络融合逐步过渡到无线宽带网络的策略,重点对多跳网络的可融合性进行了分析。最后指出无线宽带网络所面临的挑战,并预测了未来无线宽带网络的发展趋势。     

Wireless Mesh Networks for In-Home IPTV Distribution

IPTV is considered to be the next killer application. A key, challenging issue is in-home IPTV distribution with affordable deployment cost and sufficient flexibility, scalability, and reliability. In this article, we first survey and compare the emerging wired and wireless communication technologies for broadband home networks, including transmission over power lines, phone lines, coaxial cables or Ethernet cables, and IEEE 802.1 In, ultra wideband and millimeter wave wireless technologies. Considering these promising candidates for future broadband home networks, we propose three wireless mesh network architectures. These enable consumers to enjoy anywhere, anytime IPTV services without rewiring their homes. We compare the cost, reliability, and scalability of the three architectures. We further study their admission regions for IPTV, that is, the number of IPTV connections that can be supported simultaneously with satisfactory QoS. Analytical and simulation results with H.264 HDTV sources over wired, single hop wireless, and multi-hop wireless paths are given. These results can provide important guidelines for future broadband home network design supporting IPTV services.     

Broadband wireless access

This article reviews the technologies and potential markets, applications, and architectures for broadband wireless access. The emergence of wireless communications for cellular systems is presented, together with its projected future evolution to mobile wideband systems. The field of broadband access systems, services, and network architectures is also covered, and then systems for broadband wireless communications for indoor local area networks and outdoor public fixed access networks are discussed. Broadband wireless access systems are emerging as a new and growing area of telecommunications, since the ability to provide access without extensive installation of copper or fiber infrastructures make wireless technology well suited for broadband services. Finally, some of the key enabling technologies, such as adaptive antennas and video compression, and the future architectural directions of broadband wireless networks are presented     

6G:继续体系结构的变革

6G将是5G无线移动通信体系结构变革的延续与深化。以增强宽带与万物互联为应用驱动的网络,必然会从陆地蜂窝移动通信网向全域接入的无线通信网发展。5G开始了移动通信体系结构的变革,但还无法满足未来需求,因此它仅是变革的开端,需要不断改进。在全域接入的无线通信网中,有诸多全域接入架构技术需要6G去探索。     

Extending P2PMesh: topology‐aware schemes for efficient peer‐to‐peer data sharing in wireless mesh networks

Wireless mesh networks (WMNs) have emerged as a promising technology that provides low‐cost broadband access to the Internet for fixed and mobile wireless end users. An orthogonal evolution in computer networking has been the rise of peer‐to‐peer (P2P) applications such as P2P data sharing. It is of interest to enable effective P2P data sharing in this type of networks. Conventional P2P data sharing systems are not cognizant of the underlying network topology and therefore suffer from inefficiency. We argue for dual‐layer mesh network architecture with support from wireless mesh routers for P2P applications. The main contribution of this paper is P2PMesh: a topology‐aware system that provides combined architecture and efficient schemes for enabling efficient P2P data sharing in WMNs. The P2PMesh architecture utilizes three schemes: (i) an efficient content lookup that mitigates traffic load imbalance at mesh routers; (ii) an efficient establishment of download paths; and (iii) a data transfer protocol for multi‐hop wireless networks with limited capacity. We note here that the path establishment and data transfer schemes are specific to P2P traffic and that other traffic would use routes determined by the default routing protocol in the WMN. Simulation results suggest that P2PMesh has the potential to improve the performance of P2P applications in a wireless multi‐hop setting; specifically, we focused on data sharing, but other P2P applications can also be supported by this approach. Copyright © 2011 John Wiley & Sons, Ltd.     

The future generations of mobile communications based on broadband access technologies

The forthcoming mobile communication systems are expected to provide a wide variety of services, from high-quality voice to high-definition videos, through high data rate wireless channels anywhere in the world. The high data rate requires broad frequency bands, and sufficient broadband can be achieved in higher frequency bands such as microwave, Ka-band, and millimeter-wave. Broadband wireless channels have to be connected to broadband fixed networks such as the Internet and local area networks. The future-generation systems will include not only cellular phones, but also many new types of communication systems such as broadband wireless access systems, millimeter-wave LANs, intelligent transport systems, and high altitude stratospheric platform station systems. Key to the future generations of mobile communications are multimedia communications, wireless access to broadband fixed networks, and seamless roaming among different systems. This article discusses future-generation mobile communication systems.     

On architectures for broadband wireless systems

The growing popularity of portable and mobile computing and communication devices, along with the introduction of wireline broadband networks, is fueling demand for wireless broadband networks. Since ATM has been accepted as the standard for broadband integrated service networks, the authors consider the problem of providing “ATM-like services” to mobile devices. The fundamental issues that have to be tackled in order to provide broadband services which are currently available (or will be very shortly) to wireline hosts are discussed. The authors compare and contrast the architectures that have been proposed for extending the broadband wireline network infrastructure to the wireless environment. It is argued that transporting small ATM cells over the air leads to inefficient utilization of the already scarce transmission capacity. Subsequently, the authors propose an architecture for integrated wireless and wireline broadband networks which allows the wireline and wireless parts of the network to be designed independently, therefore allowing each to be optimized for the environment in which it operates. At the same time, the proposed architecture also permits simple and efficient interconnection between the wireline and wireless infrastructures     

ROF在无线宽带移动通信中的应用

文章从光载无线通信(ROF)的基本原理出发,提出了ROF在未来无线宽带移动通信中的多种应用方式,包括ROF技术在多体制无线接入重载中的应用以及ROF在无线移动网络中实现基站与光网络节点设备的互联等.总结了ROF的技术优势,提出了有待解决的关键技术问题.     

电信网发展的战略趋势

本文概要论述了笔者对未来电信网发展的战略趋势的看法,主要涉及网络业务的数据化趋势,网络的宽带化趋势,网络的光纤化趋势,网络接入的无线化趋势,网络的分组化趋势以及三网融合的大趋势。     

移动泛在网络的发展趋势

随着无线接入技术的快速发展,通信网络的异构性特征变得更加突出,如何有效地实现不同网络间的互联互通以及获取所需的各类服务,并构建融合各网络异构性的移动泛在网络成为业界关注的重点。下一代移动网络(NGMN)项目综合考虑业务、终端和网络各方面的因素,是运营商主导的近期需求愿景,而移动泛在业务环境(MUSE)是学术界的学者们对于未来移动异构泛在网络的理想化的规划和设计,更着眼于远期的融合。未来的移动通信网络将逐渐向一个综合的网络体系平滑演进,为泛在移动宽带服务提供一个全新的平台。     

Capacity and delay of hybrid wireless broadband access networks

An optical network is too costly to act as a broadband access network. On the other hand, a pure wireless ad hoc network with n nodes and total bandwidth of W bits per second cannot provide satisfactory broadband services since the pernode throughput diminishes as the number of users goes large. In this paper, we propose a hybrid wireless network, which is an integrated wireless and optical network, as the broadband access network. Specifically, we assume a hybrid wireless network consisting of n randomly distributed normal nodes, and m regularly placed base stations connected via an optical network. A source node transmits to its destination only with the help of normal nodes, i.e., in the ad hoc mode, if the destination can be reached within L (L /spl geq/ 1) hops from the source. Otherwise, the transmission will be carried out in the infrastructure mode, i.e., with the help of base stations. Two transmission modes share the same bandwidth of W bits/sec. We first study the throughput capacity of such a hybrid wireless network, and observe that the throughput capacity greatly depends on the maximum hop count L and the number of base stations m. We show that the throughput capacity of a hybrid wireless network can scale linearly with n only if m = Ω(n), and when we assign all the bandwidth to the infrastructure mode traffics. We then investigate the delay in hybrid wireless networks. We find that the average packet delay can be maintained as low as Θ(1) even when the per-node throughput capacity is Θ(W).     

无线宽带通信系统及应用

无线通信正处于从窄带传输向宽带传输过渡的发展时期。苯文简单介绍无线局域网、宽带综合数字网、第三代移动通信系统和无线ATM网络几种无线宽带通信系统及其应用。     

Mobile broadband system (MBS): trends and impact on 60 GHz bandMMIC development

The RACE mobile broadband system (MBS) project aims to extend the broadband integrated services digital network (B-ISDN) to mobile users. To meet the future demand for broadband wireless picocell networks, frequencies have been allocated in the 62-63 and 65-66 GHz bands. However, for the use of a mobile broadband system to become widespread it is necessary to develop relatively low cost transceivers based on millimetre wave GaAs P-HEMT MMICs. A transceiver architecture and elementary building blocks have been defined. 60 GHz transistor models have been refined and circuit design, layout and simulation achieved. Future cost decrease is a function of the MMIC manufacturing yield, since a high yield allows a higher layout density and consequently fewer MMICs per transceiver, and of the improvement in packaging techniques above 60 GHz     

固定宽带无线接入与移动宽带无线接入的比较

现今,信息通信从窄带向宽带、从有线向无线转变乃大势所趋。随着中国各运营商通信网络的迅猛发展,用户对网络的平均服务质量要求也越来越高,宽带无线接入技术作为一种有效的宽带解决方案而普遍地受到了人们的重视。那么,固定宽带无线接入与移动宽带无线接入有什么不同呢?本文首先在研究了固定宽带无线接入系统与移动宽带无线接入系统的网络结构后,重点讨论了两者的不同之处,即做了一个对比研究。希望能给相关人员有所参考。     

Quality of service challenges for wireless mobile ad hoc networks

Wireless mobile ad hoc networks consist of mobile nodes interconnected by wireless multi‐hop communication paths. Unlike conventional wireless networks, ad hoc networks have no fixed network infrastructure or administrative support. The topology of such networks changes dynamically as mobile nodes join or depart the network or radio links between nodes become unusable. Supporting appropriate quality of service for mobile ad hoc networks is a complex and difficult issue because of the dynamic nature of the network topology and generally imprecise network state information, and has become an intensely active area of research in the last few years. This paper

1 This article, except for some minor changes, is essentially the same as one that appears in 103 . The latter is a revised and updated version of 51

presents the basic concepts of quality of service support in ad hoc networks for unicast communication, reviews the major areas of current research and results, and addresses some new issues. The principal focus is on routing and security issues associated with quality of service support. The paper concludes with some observations on the open areas for further investigation. Copyright © 2004 John Wiley & Sons, Ltd.     

Contrôle de puissance dans les réseaux ad-hoc

In an ad-hoc network, mobile stations communicate with each other using multi-hop wireless links. There is no stationary infrastructure such as base stations. Each node in the network also acts as a router, forwarding data packets for other nodes. In this architecture, mobile stations have a multi-hop path, via other mobile stations acting as intermediaries or relays, to indirectly forward packets from source to destination. Adjusting the transmitted power is extremely important in ad-hoc networks due to at least the following reasons. The transmitted power of the radio terminals determines the network topology. The network topology in turn has considerable impact on the throughput (fraction of packets, sent by a source, and successfully received at the receiver) performance of the network. The need for power efficiency must be balanced against the lifetime of each individual node and the overall life of the network. Power control problem can be classified in one of three categories. The first class comprises of strategies to find an optimal transmitted power to control the connectivity properties of the network. The second class of approaches could be called power aware routing. Most schemes use some shortest path algorithm with a power based metric, rather than a hop count based metric. The third class of approaches aim at modifying the mac layer. We use distributed power control algorithms initially proposed for cellular networks. We establish a classification of power control algorithms for wireless ad-hoc networks. We evaluate these algorithms in anIeee 802.11b multi-hop wireless ad-hoc LAN environment. Results show the advantage of power control in maximizing signal-to-interference ratio and minimizing transmitted power.     

新3G系统——无线移动因特网

本文提出一种新3G系统,这种新3G系统立足于3G框架之内,使用3G的工作频率,采用现有的技术实现具有IMT－2000以后系统特征的宽带无线移动因特网系统。运营商可以利用其已有的固定宽带因特 资源建设发展宽带无线移动因特网,并且可以以极低成本在其上提供新话音和多媒体业务,我国发展新3G系统将引领世界宽带无线移动因特网发展潮流。     

An efficient and fair cooperative approach for resource management in wireless networks

In cellular networks, the implementation of various resource management processes, such as bandwidth reservation and location updates, has been based on the one‐to‐one resource management information exchange paradigm, between the mobile nodes and the base stations. In this paper, we design and demonstrate the use of a distributed cooperative scheme that can be applied in the future wireless networks to improve the energy consumption for the routine management processes of mobile terminals, by adopting the peer‐to‐peer communication concept of wireless ad hoc networks. In our approach, the network is subdivided into one‐hop ad hoc clusters where the members of each cluster cooperate to perform the required management functions, and conventional individual direct report transmissions of the mobile terminals to the base stations are replaced by two‐hop transmissions. The performance evaluation and the corresponding numerical results presented in this paper confirm that our proposed scheme reduces significantly the overall system energy consumption when compared with the conventional one‐to‐one direct information management exchange approach. Furthermore the issue of fairness in dynamically selecting the various cluster heads in successive operational cycles of the proposed scheme is analyzed, and an enhanced algorithm is proposed and evaluated, which improves significantly the cluster head selection fairness, in order to balance the energy consumption among the various mobile terminals. Copyright © 2005 John Wiley & Sons, Ltd.     

基于FTTx的下一代通信网精确覆盖系统的设计与实现

在"宽带中国"上升为国家战略的大背景下,有效支撑移动宽带和固定宽带业务的发展是当前及今后一段时期通信网络转型的一项重大举措,也是室内深度覆盖建设转型的契机。通过探讨基于FTTx的下一代通信网精确覆盖系统的设计、系统基本原理、硬件电路原理及系统硬件实现等方面,为各运营商在无线网室内精确覆盖方案的制定提供一定的参考。     

基于无线Mesh网络的物流信息传输平台设计

无线Mesh网络是一种新型的宽带无线网络结构,即一种高容量、高速率的分布式网络,它不同于传统的无线网络,可看成是WLAN和移动AdHoe网的融合,且发挥了两者的优势。无线Mesh网络逐渐进入民用商业化研究开发和应用阶段。在此基于无线Mesh网络这一热点技术日益成熟的背景,采用无线Mesh网络主要技术及拓扑结构;在需求分析的基础上,设计基于无线Mesh网络的物流信息传输平台,并应用于实际的工商业领域中。该设计获得了良好的社会效益,具有投资少、技术成熟的特点。