WiMax系统阶段性发展思考

作为新的宽带无线接人系统，WiMax具有比以往无线接人系统更为强大的能力，比如对移动性的支持，对QoS的支持，基于IP的架构等，诸多特性使人们对它充满了期待，但这些特性是否是WiMax制胜之宝还不能最后确认。为WiMax找到正确的市场定位，制定合理的阶段性发展策略是当前WiMax发展应该思考的问题。     

TD-SCDMA和WiMAX技术融合实现宽带无线移动通信系统

本文主要论述了基于TD-SCDMA和WiMAX技术融合实现一种新型的宽带无线移动通信系统。在该系统中,TD-SCDMA接入网提供广域无线覆盖,支持高移动性,提供话音业务和中、低速数据业务;WiMAX接入网提供热点区域覆盖,支持游牧移动性,提供高带宽流媒体数据服务,两种接入技术在网络层实现汇聚,通过网络层移动性管理技术,共享核心网络和业务系统,实现两种接入网的统一的无线资源管理以及统一的用户管理和计费,移动终端可以在该系统下的两种网络之间实现无缝漫游和切换。该种新型的移动通信系统能够很好的满足用户对移动通信业务的使用要求,也能够有力支持TD-SCDMA大规模独立组网,增强TD-SCDMA的竞争力;同时,也为TD-SCDMA系统的演进和跨越式发展提出新的思路。     

TD-SCDMA和WiMAX技术融合实现宽带无线移动通信系统

本文主要论述了基于TD-SCDMA和WiMAX技术融合实现一种新型的宽带无线移动通信系统.在该系统中,TD-SCDMA接入网提供广域无线覆盖,支持高移动性,提供话音业务和中、低速数据业务;WiMAX接入网提供热点区域覆盖,支持游牧移动性,提供高带宽流媒体数据服务,两种接入技术在网络层实现汇聚,通过网络层移动性管理技术,共享核心网络和业务系统,实现两种接入网的统一的无线资源管理以及统一的用户管理和计费,移动终端可以在该系统下的两种网络之间实现无缝漫游和切换.该种新型的移动通信系统能够很好的满足用户对移动通信业务的使用要求,也能够有力支持TD-SCDMA大规模独立组网,增强TD-SCDMA的竞争力;同时,也为TD-SCDMA系统的演进和跨越式发展提出新的思路.     

试论无线接入技术

无线接入网是通信网的重要组成部分，是有线网接入部分的补充和延伸。它具有应用灵活、安装快速、可提供一定程度的移动性等优点。列举了无线接入技术的几种系统结构和接入方式，对无线接入网的发展前景作了初步探讨     

无线接入网技术大有可为

无线接入网技术在通信技术中占有重要的位置，由于运用环境、传输距离、采用技术和使用频段的不同，无线接入网技术可分为蜂窝、微蜂窝技术、甚高频和特高频技术、点对点数字微波技术、短波技术、卫星通信技术等。随着技术进步，频谱利用率愈来愈高，容量不断扩大，抗干扰能力增强，设备简化，价格降低，无线接入技术将大有可为。一、无线接入网技术1．无线接入网技术概述无线接入网技术是在接入网的部分或全部采用无线传输媒质，向用户提供固定终端业务和移动终端业务，结构见图1。无线接入网技术广泛应用在我国的城市和广大农村通信网中。…     

新一代移动承载网:IPRAN网络

文章认为采用IP无线接入网(IPRAN)网络逐步代替多业务传送平台(MSTP)网络已是运营商网络发展的重要趋势。部署新型IPRAN网络也面临着很多挑战,需要考虑组网模型、多业务承载、QoS保障和端到端管理等诸多问题。文章指出如何实现MSTP与IPRAN的互联互通成为了IPRAN网络演进中的重要课题。     

无线接入网综述

1 接入网与无线接入网 整个通信网分为两部分:核心网(市话端局以上部分)与接入网(市话端局或远端模块以下的网络部分)。 接入网是指从本地交换局到用户之间的信息传送网。通信业务的发展对接入网提出了数字化、宽带化、灵活、可靠、易于管理等要求,希望一条用户线可     

个人移动通信系统

随着无线接入技术的飞速发展与移动终端的不断小型化，以数字蜂窝、无绳电话、寻呼以及卫星通信等为代表的第2代移动通信系统迅速发展，目前已能提供多种业务，并占据了相当的市场。从本质上看，它们只能提供终端对终端的移动通信业务，而不是个人对个人的通信。针对这一情况，世界上在发展第3代移动通信系统时，提出了一种个人移动通信的概念：即由无线接入提供的终端移动能力、基于个人号码的个人移动性以及由个人业务环境所管理的业务移动性的综合，以保证用户在任何地点、任何时间、与任何人、以任何方式的通信成为可能。目前关于第3代…     

开放天空下的审视--宽带无线接入市场的未来前景

开放的天空国家“十五”计划明确指出，要大力发展高速宽带信息网，重点建设宽带接入网……目前网络接入技术正由单纯为解决电话业务而构建的窄带接入网，将向融合多种接入手段的、能够提供多种综合业务的综合接入网方向转变。积极发展接入网特别是宽带接入网，消除信息化最后一公里瓶颈，满足人们对宽带多媒体通信的接入需求，这是我国信息化发展的必然要求。这意味着政府和电信管理部门必然会在无线宽带接入方面扩大投资、加大支持力度，使这项新方案的发展搭上积极政策的“顺风船”。这对于在频率分配和市场规范上有着严格要求的无线技术…     

LTE/SAE系统中用户移动性管理的研究与分析

文章首先介绍了LTE网络下的移动性管理功能,然后对用户的移动性管理状态进行了描述,并用图形法描述了LTE移动状态之间的转移,最后分别对空闲状态、连接状态和3GPP无线接入系统之间的移动性管理进行研究与分析,分析表明,提出的移动性管理机制能够解决移动通信网络的安全性、可靠性和端到端的QoS保证。     

基于移动IP的组网方案探讨

下一代无线通信标准将能提供无缝、高QoS、高速率的基于IP的无线业务。IEEE802．16宽带无线接入技术WiMax的出现使得无线网络向4G过渡成为可能。WiMax技术将作为宽带无线接入应用。对比了WiMax和Wi-Fi的技术，提出一个融合Wi-Fi和WiMax的组网解决方案。     

Optimal Radio Resource Partition for Joint Contention- and Connection-Oriented Multichannel Access in OFDMA Systems

The IEEE 802.16e world interoperability for microwave access (WiMax) system plays an important role in the future wireless metropolitan area network (WMAN). Orthogonal frequency division multiple access (OFDMA), adopted in the IEEE 802.16 e WiMax system, has many advantages in the physical layer, but also poses many challenges for radio resource allocation. One of interesting radio resource allocation issue in the OFDMA system is to partition the overall radio resource (bandwidth and time duration) into two portions: one for random access and the other for connection-oriented access. In the IEEE 802.16 e WiMax system, a truncated binary backoff algorithm is adopted to resolve the contention in random access, while the time-division OFDMA is used for the connection-oriented access. The main contribution of this paper is to design an analytical approach to determine the optimal amount of reserved radio resource in both time and frequency domains for random access, with the objective of maximizing the overall efficiency of radio resource while satisfying the delay requirements for supporting real-time services. Furthermore, an analytical model for calculating the access latency and the efficiency of the reserved radio resources is developed.     

下一代通信网络中基于策略机制的无线资源管理

下一代无线通信系统是一种异构的网络体系,集成多种无线接入技术（Radio Access Technology,RAT）的同时提供多种窄带和宽带多媒体业务。这样的网络环境需要先进的RRM方法来处理复杂多变的无线信道、网络资源的动态配置及保障不同特征业务的服务质量（QoS）,给无线资源管理（Radio Resource Management,RRM）带来了巨大的技术挑战。本文通过引入对网络进行策略控制的思想,提出了一种基于策略机制的通用方法,致力于解决下一代异构（heterogeneous）网络中的无线资源管理。文中着重讨论了基于策略机制的网络接入控制、切换,以及基于策略机制的QoS管理,给出了各功能模块的工作原理和通信过程的分析与设计。     

一种适合高速铁路的宽带无线接入网络架构

快速发展的高速铁路是需要覆盖移动语音和数据业务的新热点场景,这使得高速铁路宽带无线接入系统成为研究重点。根据高速铁路的特定环境,本文提出了一种基于光载无线通信技术的新型高速铁路宽带无线接入网络架构,阐述了相对应的媒体接入控制方案,并对其移动性管理进行了说明。     

A global architecture for the Wi-family

WiMedia, Wi-Fi, WiMax, Wi-Mobile, WiRAN, the Wi-family is getting bigger; so does the network architecture. It is encouraging to see the fast development of the new IEEE wireless technologies promising the ultimate Internet service deployment on wireless and mobile infrastructures since they would offer larger bandwidth at cheaper price compared to the telecommunication wireless radio resource. However it is disquieting to see that the TCP/IP protocol stack which is supposed to be the heart of the Internet services deployment is not evolving as fast as the wireless technologies do. Here we come up with the hard question which is the network performance of the TCP/IP architecture over wireless networks. It is probably too early to decide to replace TCP/IP by another protocol stack for wireless network support, but it is important to not ignore the problem and analyse the main drawbacks of TCP/IP in wireless networks and think about a new architecture of network communication over the wireless networks. This paper provides a brief survey of what we name here the Wi-family wireless technologies, and emphasizes on new network architecture to optimize the TCP/IP behaviour worsen by the wireless characteristics.     

Handover approaches for seamless mobility management in next generation wireless networks

Next generation wireless networks (NGWN) will be an integration of heterogeneous wireless access networks that will interwork over an IP‐based infrastructure. This all‐IP vision has led to the development of handover mechanisms to support seamless mobility for active network services among the different interworking wireless networks in order to ensure network access ubiquity in NGWN. These handover mechanisms need to ensure that mobile devices continue to receive ongoing communication without any noticeable disruption during handover events among the heterogeneous networks. This paper gives a qualitative and quantitative review of current handover approaches of IP mobility management protocols for NGWN with an objective to introduce a new way of further optimizing the handover performance. In particular, the paper focuses on handover approaches of mobile IPv6 (MIPv6) based mobility management protocols. Thus, the need, benefits, and limitations of these handover approaches are explored. Thereafter, dynamic handover coordination is introduced as a new viable solution that exploits the benefits and mitigates the limitations of these handover approaches hence improving handover performance in terms of handover delay, packet loss, and signaling overhead. Copyright © 2011 John Wiley & Sons, Ltd.     

Mobility management in wireless ATM networks

Mobile ATM offers a common wired network infrastructure to support mobility of wireless terminals, independent of the wireless access protocol. In addition, it allows seamless migration to future wireless broadband services, such as wireless ATM, by enabling mobility of end-to-end ATM connections. In spite of the diversity in mobile networking technologies (e.g., cellular telephony, mobile-IP, packet data services, PCS), all of them require two fundamental mechanisms: location management and handoff. This article describes different schemes for augmenting a wired ATM network to support location management of mobile terminals and handoff protocols for rerouting a connection data path when the endpoint moves. A prototype implementation of mobile ATM integrating mobility support with ATM signaling and connection setup, is presented. It shows how mobile ATM may be used to provide mobility support to an IP terminal using non-ATM wireless access     

WiMAX networks: from access to service platform

Recently, WiMAX has been proposed as an attractive wireless communication technology for providing broadband access for metropolitan areas. Despite its salient features from the technical perspective, the success of the WiMAX network depends on its capability of providing cost-effective solutions for a variety of existing and potential services. To address this issue, we advocate the design of a new network layer that can support multihop communications efficiently in WiMAX networks and that can fully exploit the features of the WiMAX standards. In particular, we first identify services that are important for broadband wireless network providers and investigate the requirements for different services. We then discuss now to design WiMAX networks by considering issues of efficiency, security, and reliability. The key observation is that WiMAX can be properly complemented by advanced connection management and network coding techniques.     

Dynamic inter-domain MDS approach with secure seamless handover based on IEEE 802.21 MIH

The accessibility of available wireless access technologies with increasing demand for real time multimedia application becomes an essential part for mobile communication. Mobile users resourcefully utilize the heterogeneous environment for best quality of service (Qos) anywhere and anytime. Efficient handover optimization and intelligent mobility management is a key requirement for designing next generation wireless networks. Therefore, a novel IEEE 802.21 media independent handover (MIH) standard is adopted to provide an associated service for intelligent handover procedures. In addition, dynamic mobility management decision server (MDS) and IEEE 802.21a security extension for MIH services are also integrated in the proposed architectures to support fast, seamless and secure handover optimization in inter-domain mobility. Simulation results prove that the presented work resourcefully minimizes the packet loss, unnecessary handover probability and vertical handover delay by avoiding time consuming scanning process for target network discovery. The system thus achieves Qos guarantee by balancing the network load and throughput improvement for different applications with Proxy MIPv6 mobility management protocol.