A Simulation Study on Channel Estimation for MIMO-OFDM Based Beyond 3G Mobile Systems

1 Introduction Future wireless cellular communication networks areexpected to fully support multi-media services on a real-ti me basis ,therefore pose a challengingissue of develop-ing high-speed access and high data-rate transmissiontechnologies , which are not satisfied by current 2nd-and3rd-generation cellular mobile communications net-works[1]. Orthogonal Frequency Division Multiplexing(OFDM) has become a popular technique for high datarate wirelesstransmission duetoits many advantagesfo…     

Opportunities for IP in Communications Beyond 3G

Future communication will be based on TCP/IP as common network and transport layers to provide global connectivity to users and applications. IP is used to provide ubiquitous access across different access networks and exploits the benefits of a common connectivity layer while reducing the cost of operation and maintenance of the network. This paper discusses the opportunities for IP in the evolution towards a future broadband, all-IP mobile communication network. In particular, we argue for three opportunities for the future: Interworking access technologies over IP, IP layer transparency, and the ability to manage complexity.Thomas Toftegaard Nielsen was born on September 26th 1970 in Århus, Denmark. He holds a M.Sc.E.E. (‘95) and a Ph.D. (‘99) degree in mobile radio communications from Aalborg University, Center for PersonKommunikation, Denmark. In 1996, he joined the Danish mobile operator Sonofon, where he was involved in capacity and performance evaluations and enhancements of the frequency hopping GSM BSS system as well as advanced wireless network planning. In 1999 he was appointed senior radio project manager, where he became technically responsible for the GPRS mobile data dimensioning/planning. In 2000 he joined Ericsson Telebit A/S as wireless IP software development manager. Currently he is responsible for Ericsson’s IPv6/IPv4 termination dual-stack used in the Ericsson 2G, 2.5G and 3G terminal platforms, in parts of the Ericsson 2G and 3G access network as well as in the Ericsson MSC and MGW of the 3G core network.Rune Hylsberg Jacobsen was born in Copenhagen, Denmark, on October 12th, 1970. He holds a M.Sc. degree in physics and chemistry (1995) and a Ph.D. degree in physics (1997) from University of Aarhus. In 1996 he guested Bell Laboratories, Lucent Technologies, USA. During this period he conducted research in optoelectronic, terahertz-bandwidth radiation applied to material characterization. In 1997 he joined the R&D unit of the Danish telecommunication operator TDC where he worked on fixed broadband access, with emphasis on ADSL deployment and the characterization of transmission properties of the local loop. In 1999 he joined Ericsson Telebit A/S and started to work on European research projects in the 4th and 5th EU framework programs. He was appointed department manager for a software development unit in year 2000. In this position he was in charge of an IP router development for the radio access network and has since worked with aspects of using IP for wireless communication systems.     

B3G TDD系统的基带链路架构与时序设计

本文通过参与“863”FuTURE项目中B3G TDD系统的设计与实现过程,探讨B3G系统中基带时序设计和系统中存在的问题,并给出解决方法。     

基于SIP协议的3G无线视频终端设计与实现

首先介绍了SIP的基本功能和事务层的处理机制,然后在此基础上提出了基于SIP协议的3G无线视频终端的多线程整体设计方案,并给出了实现流程图。按照会话的建立顺序详细描述了视频通信的建立、会话和终止过程中UAC与UAS的交互过程,并给出了详细的软件设计。该方案充分利用了SIP协议基于IP的设计思想和基于文本的协议解析模式,具有很强的可自定义性和扩展性,软件采用多线程设计,具有很强的功能扩展性。     

OFDM技术应用于Beyond 3G的仿真研究

介绍了Beyond3G的基本要求,分析了OFDM技术的特点,建立了OFDM技术应用于Beyond3G的仿真模型,对不同调制方式和不同应用信道模型进行了仿真研究。研究表明:OFDM系统可以有效克服多径干扰和多卜勒效应,能够应用于Beyond3G。     

空时码及其在后3G宽带移动通信中的应用

空时码具有频谱效率高、抗衰落能力强等突出优点。在介绍空时码的MIMO信息论基础上,系统地对三类空时码进行了分析比较。并对空时码在后3G这样的宽带移动通信系统中如何应用进行了探讨。     

基于3G网络的远程无线监控系统设计

针对远程无线监控系统的应用需求和移动通信的发展,提出一种基于2G/2.5G/3G网络的远程无线监控系统,设计了系统的总体方案,介绍了系统的组成结构和工作原理,着重阐述了系统的硬件和软件设计。该系统拓展了移动通信网络的应用范围,提高了远程监控系统的灵活性和稳定性,具有广泛的应用前景。     

Generic Architecture and Mechanisms for Protocol Reconfiguration

The next generation of wireless mobile communications termed beyond 3G (or 4G), will be based on a heterogeneous infrastructure that comprises different wireless networks in a complementary manner. Beyond 3G will introduce reconfiguration capabilities to flexibly and dynamically (i.e., during operation) adapt the wireless protocol stacks to better meet the ever-changing service requirements. For the dynamic reconfiguration of protocol stacks during runtime operation to become a practical capability of mobile communication systems, it is necessary to establish a software architecture that functionally supports reconfiguration. In the present paper, a generic architecture and respective mechanisms to achieve protocol stack and component based protocol layer reconfiguration are proposed.

一种改进的WLAN-3G融合网络认证协议

本文在分析了现有3GPP WLAN-3G融合网络接入认证协议EAP-AKA的优势和不足的基础上,引入WAPI证书鉴别机制,提出WAPI-3G互联结构模型,并针对该互联模型设计了一种接入认证协议EAP-WAPI.本文提议的WLAN-3G互联结构模型及接入认证机制解决了融合组网环境下WLAN终端统一接入认证的问题.分析和仿真结果表明,相比于原有的WAPI认证协议WAPI-XG1,本文所提议的协议具有较高的安全性和执行效率.     

The WINNER (Wireless World Initiative New Radio) Project – Development of a Radio Interface for Systems Beyond 3G

WINNER is an international research project under Framework Program 6 (FP6) of the European Commission. The main objective is the development of the new radio interface for systems beyond 3G. WINNER is part of the Wireless World Initiative (WWI), which is a series of cooperating projects in FP6 to develop future systems including all entities from a system perspective. The project is developing all system functions from layer 1 to 3 including cooperation mechanisms with legacy systems as part of the overall architecture for systems beyond 3G. Based on usage scenarios and propagation investigations, technical requirements are derived. The physical layer and higher layer protocols are designed. A new broadband radio interface requires newly identified frequency spectrum. WINNER is contributing to the international regulatory process in ITU-R towards the preparation of WRC 2007 (World Radiocommunication Conference). This paper provides an overview about the WINNER project and its activities.     

一种适用于B3G移动通信系统下行共享信道的调度算法

本文针对后三代(B3G)移动通信系统中的宽带无线信道特性和流媒体业务特征,分析了可用于高速下行共享信道的各种传统分组调度算法,提出面向流媒体业务能够提高系统吞吐量的基于优先级公平调度(Priority-Based Fairness Scheduling,PBFS)算法.该算法根据各移动用户收发信道质量和业务传输的QoS要求动态调整各用户的业务传输优先级,确定下行共享信道的调度方案.并给出该算法的简化形式S-PBFS.仿真结果表明,与传统调度算法相比,S-PBFS算法在数据包传输时延受限的条件下具有无线信道利用率高、实现复杂度低等特点.     

Reconfigurable Component-based Middleware for Networked Embedded Systems

Next generation embedded systems will be composed of large numbers of heterogeneous devices. These will typically be resource-constrained (such as sensor motes), will use different operating systems, and will be connected through different types of network interfaces. Additionally, they may be mobile and/or form ad-hoc networks with their peers, and will need to be adaptive to changing conditions based on context-awareness. Our focus in this paper is on the provision of a middleware framework for such system environments. Our approach is based on a small and efficient ‘middleware kernel’ which supports highly modularised and customisable component-based middleware services that can be tailored for specific embedded environments, and are runtime reconfigurable to support adaptivity. These services are primarily communications-related but also address a range of other concerns including service discovery and logical mobility. In the paper we provide an overview of our approach, focusing in detail on both the middleware kernel and the services. We also discuss an application scenario in which we are currently applying and evaluating our middleware approach.

A Management Framework for Ambient Systems Operating in Wireless B3G Environments

As the wireless world is rapidly evolving towards the “Beyond the 3rd Generation” (B3G) era, communication infrastructures need to tackle external conditions that are continuously changing, and thus become less predictable in terms of quality of service (QoS) provision. On the contrary, the B3G era, through the coexistence and complementary use of a multitude of Radio Access Technologies (RATs), offers additional capabilities for providing users with advanced levels of convenience and flexibility for living and working. Those advances in communications and networking technology are making it possible to devise ‘ambient’ systems, i.e. systems that realize the vision of an all-encompassing multimedia networking environment, which is aware of the users’ presence and context, and is sensitive, adaptive, and responsive to their needs, habits, gestures and emotions. All above pose significant challenges regarding the intelligent management of heterogeneous wireless infrastructures. In the light of the above, this paper presents such an advanced management framework, as an enabling technology for designing and developing ambient, wireless systems in B3G environments. The paper focuses on the main components of the proposed framework, as well as on their functionality and interactions. Additionally, indicative simulation results showcase the efficiency of the proposed framework.     

Handover and New Call Admission Policy Optimization for G3G Systems

Handover blocking of ongoing calls due to the mobility of users is a quantity that determines at most the Quality of Service (QoS) in microcellular and picocellular G3G systems environments. In this paper we propose a call admission policy, based on the fractional guard channel scheme, which additionally considers the blocking of new calls. Simulation results show that the proposed policy gives an improved system performance, compared to the most commonly used handover algorithms.     

一种适合3G移动的微支付方案

本方案提出利用改进后3G入网认证机制中密钥和随机数,结合AES算法生成安全性高的一次性签名,且计算量和存储量很少,具有不可否认性,还利用了登录第三方网站后生成的用户临时标识,具有很好的匿名性和不可跟踪性。其中商家受到第三方的监视和管理,防止用户和商家的欺诈,用户收到商品后对商家的信用进行评价,具有公平性。该方案交易灵活、效率高,适合3G用户实行微支付交易。     

3G无线网络的IP技术研究

论述了当前主要研究的支持3G无线网络的IP技术、移动IP、蜂窝IP、HAWAII和TeleMIP，并对它们进行了比较分析，总结了当前的无线IP技术的特点和发展趋势。     

基于公钥密码体制的3G认证协议改进

文章对原3GPP认证协议进行了安全分析,提出其存在的安全漏洞,并根据公钥密码体制思想,在保持原有3GPP认证过程的基础上提出一种新的认证过程,并对该过程的安全性和可实施性进行了分析。     

基于3G的移动自组网终端设计

根据移动自组网(MANET)的特性,介绍了一种基于TD-SCDMA的移动自组织网络终端的设计方案.这些终端所组成的网络系统能实现自组织的功能且可与3G蜂窝网络连接.     

G.723.1 Codec在OpenH323协议栈上的实现

OpenH323是一个开放源码的VoIP(Voice over IP)协议栈,支持H．323和SIP等多媒体通信协议,为多媒体应用提供了一个很好的开发平台。G．723．1是ITU-T建议在中低速率多媒体通信中使用的语音压缩算法,目前该算法已在IP电话系统中得到广泛应啊。基于OpenH323协议栈实现G．723．1Codec有着十分重要的应用价值。介绍在OpenH323的软件终端上实现G．723．1Codec的基本方法,并可推广到G．729等其它多种语音压缩算法。