下一代无线通信系统和支撑业务探讨

首先详细介绍了各种未来无线通信系统的有关情况．然后着重介绍了未来无线通信系统支撑业务的类型和网络参考模型．最后展望了下一代无线通信系统的光明前景。     

下一代无线通信的目标及发展趋势

下一代无线通信的目标下一代无线通信要提供无所不在的业务。无所不在不仅指使用业务的环境等条件不受限制，更指业务类型覆盖面广，可满足不同需求。这就要求无线通信技术不断发展。从现有的2G和已出现的2.5G和3G系统的发展和逐步成熟，可以看到这一目标实现的可能性。2G提供了相对便宜且有效的话音业务。而2.5G和3G引入了数据和高速数据业务，其中包括一些视频业务。虽然采用无线局域网（WLAN）和无线城域网（WMAN）技术的大规模的网络的建设还处于初期，但该技术已开始流行。其实，这些方式及其扩展的目的都是为了实现全IP网络，…     

世界通信大会首次来华中兴通讯倡导LTE、FTTX等下一代通信技术

第43届世界通信大会于2008年5月19日至23日在北京举行。中兴通讯作为主赞助商携手中国移动、中国电信以及全球多家一流运营商与会,就中兴通讯全面部署的下一代网络建设战略进行阐述,包括中兴通讯TDLTE和WCDMALTE无线通信发展路线图、FTTx下一代固定接入网络建设思路及经验、以及下一代增值业务和基于AVs的IPTV等创新业务的内容。     

专题导读

在过去的10年中,移动通信已成为通信信息领域投入最大、发展最快的技术,成为实现随时随地获取信息的重要途径,多业务、宽带化已成为移动通信追求的目标。但是,无线通信有限的频谱资源和有限的传输距离使它的发展受到很大的制约。光通信的宽带、低损耗特性与无线通信有很好的互补性,无线通信与光通信融合是通信技术发展的必然趋势,光载无线（RoF）技术应运而生。     

3G技术构筑宽带通信的理想平台

第三代移动通信技术以其特有的优势，成为下一代无线通信的必然选择，高品质的通信技术和网络布局是实现未来3G宽带无线通信业务的重要保障。     

NGN发展带来的信息安全机遇

下一代信息通信网络下一代信息通信网络(NGN)究竟是什么?可以说,它的内涵是相当丰富的,以智能光网为核心的下一代光网络,以MPLS和IPv6为重点的下一代IP网络以及3G、4G的下一代无线通信网络都在NGN的探讨范畴当中。从电信发展的现状来看,业务提供成为市场关键,而NGN恰好提供了能运行灵活多样综合业务的网络平台,所以NGN这一结合多种网络优势和特点的全新的网络体系结构已经成为国内外电信运营商及制造商关注的重点,并已在逐步构建。     

下一代移动通信网络架构

文章介绍了下一代无线通信系统，论述了下一代无线通信的接入系统，软件系统及关键技术，设想了未来移动通信应具有的基本特征及实施下一代无线通信系统可能遇到的困难。     

移动互联网的发展和应用浅析

随着近两年我国移动3G技术的发展,智能移动终端用户的普及,移动互联网这种新兴的业务正在快速发展,移动互联网技术将会在未来一段时期占据无线通信网络的的主导地位.就像本世纪初的语音通信时代一样,手机以“随时随地”通话的优势,其用户量快速增长,在今天,“移动互联网”也会以“随时随地”的优势迅猛发展,改变人们的生活和通信方式.     

WMAN与WLAN、3G无线数据业务的关系探讨

随时随地的个人无线通信是通信业发展的目标,市场需求的不断增加和宽带无线接入技术的成熟使得无线城域网(WMAN)呼之欲出。本文从运营的角度研究了WMAN同WLAN(无线局域网)、3G所提供的宽带无线接入业务的差异,探讨了它们之间的关系,并给出了基本结论。     

软交换在3G网络中的应用与意义

控制、承载、业务的分离，则NGN（Next Generation Network,下一代网络）以及软交换（softwitch）技术的核心概念，3G技术则是目前无线通信技术的重要发展方向。本文在简单介绍NGN体系结构的基础上，对UMTS（通用移动通信系统）Release5核心网的技术构成进行了分析。借助于软交换技术，UMTS Release5也实现了控制、承载、业务的分离，从而可以保证3G网络与下一代网络的顺利融合。     

Next-generation wireless communications concepts and technologies

Next-generation wireless (NextG) involves the concept that the next generation of wireless communications will be a major move toward ubiquitous wireless communications systems and seamless high-quality wireless services. This article presents the concepts and technologies involved, including possible innovations in architectures, spectrum allocation, and utilization, in radio communications, networks, and services and applications. These include dynamic and adaptive systems and technologies that provide a new paradigm for spectrum assignment and management, smart resource management, dynamic and fast adaptive multilayer approaches, smart radio, and adaptive networking. Technologies involving adaptive and highly efficient modulation, coding, multiple access, media access, network organization, and networking that can provide ultraconnectivity at high data rates with effective QoS for Next Gare are also described     

Position location using wireless communications on highways of thefuture

With the advances in wireless communications and low-power electronics, accurate position location may now be accomplished by a number of techniques which involve commercial wireless services. Emerging position location systems, when used in conjunction with mobile communications services, will lead to enhanced public safety and revolutionary products and services. The fundamental technical challenges and business motivations behind wireless position location systems are described, and promising techniques for solving the practical position location problem are treated     

Wireless loops: What are they?

Several loop applications of wireless technology are aimed at reducing the cost of deploying communications services ranging from telephone to wideband video. In these applications, wireless links replace a portion of a wireline loop from a central location (a central office or cable headend) to a subscriber. The replacement of labor-intensive wireline technology by complex mass-produced integrated electronics in wireless transceivers is projected to reduce the overall cost of the resulting loop. These wireless loop applications attempt to provide existing communications services or small modifications to existing communications services. A different interpretation of a wireless loop makes use of low-power digital radio technology to provide the last thousand feet or so of a loop. Low-power low-complexity wireless loop technology in small base units can be integrated with network intelligence to provide the fixed-infrastructure network needed to support economical personal communications services (PCS) to small, lightweight, low-power personal voice and/or data communicators. Low-complexity communicators can provide many hours of “talk time” or data transmission time and perhaps several days of standby time from small batteries (≤ 1.5 oz). Because this application of wireless loop technology can reduce the inherent costs in several parts of a wireline loop, it has the potential to provide convenient widespread PCS at less costs than providing telephone services over conventional wireline loops. This low-power wireless loop application does not fit into any existing communications system paradigm. Wireless technology with tetherless access and wide-ranging mobility, e.g., the personal access communications system (PACS), does not fit the accumulated wisdom of the wireline telephony paradigm. It also does not fit the paradigm of existing cellular radio that has sparsely distributed expensive cell sites, and it is not targeted at fixed video services as is wireless cable. Because a significant change in thinking is required in addressing this new low-power low-complexity widespread wireless loop paradigm, its large economic advantages and service benefits have not yet been embraced by many of the existing communications providers, who appear to be more comfortable pursuing the better-known paradigms of video using wireless cable, or of cellular radio in the guise of high-tier PCS, or in the guise of rapid economical deployment of telephone services in developing nations. This paper discusses the inherent economic advantages and service benefits of low-power low-complexity wireless loop technology integrated with network intelligence aimed at providing economical low-tier PCS to everyone.     

频率选择性OFDM V-BLAST系统的直接解码算法

作为正交频分复用(OFDM)技术与垂直型贝尔实验室分层空时(V-BLAST)结构的结合,OFDM V-BLAST系统能更好地满足新一代宽带移动无线多媒体通信的需求.本文研究OFDM V-BLAST系统在下行频率选择性衰落环境中的解码问题.在阐述了OFDM V-BLAST系统中的联合空频解复用操作之后,本文为OFDM V-BLAST系统提出了一种新颖的半速率旋转不变性联合空频编码方法.通过利用上述旋转不变性,本文为下行频率选择性OFDM V-BLAST系统建立了一种无需了解信道状态信息(CSI)的直接解码算法.大量仿真结果表明了半速率旋转不变性联合空频编码方法的有效性和直接解码算法的性能.     

New concepts and technologies for achieving highly reliable andhigh-capacity multimedia wireless communications systems

The rapid growth of multimedia wireless communications services forces the development of advanced digital wireless systems with high reliability and high speed as well as flexibility for varying traffic conditions. To achieve such advanced wireless systems. New system design concepts different from the conventional ones aiming at increasing system capacity for voice transmission would be required. Since multimedia wireless communications require high quality, high speed, and high flexibility as well as temporary and spatial control of traffic under severe fading environments, the so-called conventional system design concept will be insufficient. New system design concepts and techniques for achieving highly reliable and high-capacity multimedia wireless communications are discussed using both time division multiple access (TDMA) and code division multiple access (CDMA) systems. The demands for high-speed and high-reliability mobile, personal, and multimedia wireless communications services strongly require matching with the trunk network constructed by a broadband optical fiber system or wired system     

Security services in group communications over wireless infrastructure, mobile ad hoc, and wireless sensor networks

Group communications in wireless networks has been facilitating many emerging applications that require packet delivery from one or more sender(s) to multiple receivers. Due to insecure wireless channels, group communications are susceptible to various kinds of attacks. Although a number of proposals have been reported to secure group communications, provisioning security in group communications in wireless networks remains a critical and challenging issue. This article presents a survey of recent advances in security requirements and services in group communications in three types of wireless networks, and discusses challenges in designing secure group communications in these networks: wireless infrastructure networks, mobile ad hoc networks, and wireless sensor networks.     

Compact multidimensional broadband wireless: the convergence of wireless mobile and access

Broadband wireless communications have gained increased interest during the last few years. This has been fuelled by a large demand on high-frequency utilization as well as a large number of users requiring simultaneous high-data-rate access for the applications of wireless mobile Internet and e-commerce. The convergence of wireless mobile and access will be the next storm in wireless communications, which will use a new network architecture to deliver broadband services in a more generic configuration to wireless customers, and support value-added services and emerging interactive multimedia communications. Large bandwidth, guaranteed quality of service, and ease of deployment coupled with the great advancements in semiconductor technologies make this converged wireless system a very attractive solution for broadband service delivery.     

宽带无线TDMA系统的自适应调制技术

无线多媒体业务的快速增长促进了宽带无线ＴＤＭＡ通信系统的研究和开发,宽带无线ＴＤＭＡ通信系统方面出现了一些新的技术和系统设计概念。讨论宽带无线ＴＤＭＡ系统中采用的自适应调制技术。     

WiMAX应用潜力分析

文章分析了WiMAX在固定宽带无线接入场合和便携、移动通信场合的应用前景.文章认为:在固定宽带无线通信中,WiMAX会广泛应用于家庭用户、IP语音用户、传输承载用户和集团客户,为他们提供宽带无线接入;在便携、移动通信中,IEEE802.16即将集成到笔记本电脑和个人数字助理(PDA)等便携式电子设备中,实现在城域网范围内的可移动的宽带无线数据服务;用户需求加上WiMAX设备的批量上市及终端成本的下降,WiMAX的应用潜力巨大,市场将呈几何级增长.