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。     

宽带可移动无线接入系统关键技术:HiperLAN/2

迅速发展的Internet业务、多媒体业务以及日益增长的移动电话用户都预示着未来几年中,宽带无线技术将在通信领域中快速发展。文章介绍了可移动无线宽带系统中HiperLAN/2的工作原理及其体系结构,并指出了HiperLAN/2的系统特征。     

Variable Cyclic Prefix for Contention-Based Wireless Access in OFDM-Based Vehicular Communication Systems

In vehicular environment, signal transmissions face more challenges than in indoor wireless local area systems. In such an unpredictable communication environment, multipath fading causes high bit error rate, which leads to higher dropping probability of packets. In order to reduce the dropping probability of handshaking packets without increasing the infrastructure capability, we propose to modify the traditional cyclic prefix into a variable cyclic prefix (VCP) of request-to-send and clear-to-send frames. By reducing the handshaking packet error rates, we improve the contention ability in carrier sense multiple access with collision avoidance scheme in vehicle-to-infrastructure transmission. Suitable VCP time slots and dynamically adjustable VCPs are predicted based on the analysis of appropriate environmental parameters.     

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。     

无线宽带通信系统的上行带宽资源分配方案

提出了一种适用于宽带无线通信系统的上行无线带宽资源分配方案。在详细描述算法的基础上，建立了对应的仿真系统对算法进行验证。该方案较好地解决了多业务并发时的上行带宽分配问题。兼顾了不同实时业务对时延和带宽的不同需求，与传统技术相比较，提高了带宽利用率，并减少了协议开销和传输时延。     

面向新一代宽带无线通信系统的分组传送技术

本文介绍了面向2G无线通信系统的城域网的现状,分析了其在承载新一代宽带无线通信系统所面临的新问题和挑战（如来自IPRAN和TD-SCDMA的空口同步需求）,最后,提出了采用分组传送网（PTN）的解决方案,并对城域分组传送技术和分组同步解决方案进行分析。     

分组数据模式在第三代移动通信系统中的应用

本文介绍了分组数据传输模式在目前主要的三种第三代移动通信技术WCDMA、cdma2000和TD-CDMA中的发展情况,分析了这三种系统的网络结构和空中接口协议分层,讨论了移动通信中分组模式与Internet的结合-移动IP在第三代系统中的应用。     

一种基于新一代蜂窝移动通信的无线资源分配方案

新一代的蜂窝移动通信系统要求支持多种业务,从高质量的交互式实时业务到基于TCP连接的完全可靠服务。对于现有的无线链路,用户各种业务量的增加造成无线资源相对使用不平衡,大大降低了无线网络的吞吐量。本文提出了一种基于新一代蜂窝通信的无线资源分配方案,并利用OPNET建立仿真平台对该方案进行验证。仿真结果表明,各种不同优先等级的业务都能得到自己满意的服务质量,链路总的吞吐量达到了1 0 0 Mbit/s     

宽带无线接入OFDM接收机的VLSI实现

基于IEEE 802.16d协议物理层标准中的OFDM模式,设计了一个接收机ASIC.整个接收机设计通过算法和结构优化,采用模块复用和流水线技术,使得接收机结构更加紧凑,运算效率更高,节省了芯片面积.另外,在实现过程中,还采用了低功耗设计技术,以满足终端对低功耗的要求.详细描述了该ASIC接收机的VLSI实现和具体优化过程,对关键算法的性能和实现复杂度进行了权衡分析.该ASIC接收机经过综合后面积为3.481 mm2,在64 QAM调制方式下,可支持最大数据速率达30 Mb/s,适合户外多径情况下的固定接入无线分组通信.     

宽带无线通信系统的零中频接收机设计

零中频(ZIF)接收机具有体积小、成本低、易于集成和扩展等优点,是宽带无线通信接收机的重要研究方向.本文首先论述了零中频接收机的系统架构,并分析了零中频接收架构所引入的本振泄漏、直流偏差、I/Q不平衡等问题及补偿算法,提出了一种可行的LTE零中频接收机设计方案.仿真结果表明,该方案能够很好地解决现有零中频接收机技术存在的问题,显著提高LTE宽带接收机的性能.     

宽带无线通信系统的研究与设计

无线通信在军事通信领域一直占有重要地位.新时期军事斗争中,指挥员需要实时地获得现场的视频、语音信息,而传统的无线电台仅仅能够传输数据和话音,已不能满足需要.设计了一种宽带无线通信系统,在研究系统组成和性能指标的基础上,重点研究了补码键控(CCK)调制解调和系统通信协议设计,该系统可用于区域电子系统的超短波数据链,实现战场综合信息的实时传输,也可用于试验训练基地的综合业务数据无线接入和场区各阵地的数据无线传输.     

移动宽带无线接入技术

本介绍了移动宽带无线接人(MBWA)技术，并介绍了两种基于该技术的产品系统结构、技术特点及其发展情况。     

空间调制无线光通信的信号设计

建立了空间调制无线光通信的光强信道模型,并给出了空间信号必须满足的两个基本约束条件。通过定义于二维空间的正交基函数建立了矢量信号空间,并定义了三个衡量空间信号设计方案性能的指标,即误符号率,频带利用效率和功率效率等。参照传统时域信号设计方案,提出了三种空间调制信号具体设计方案,并从带宽效率和功率效率两性能上进行了比较,结果表明正交幅度调制(QAM)具有带宽效率高、功率效率低的特点,而且采用的信号点越多其带宽效率就越高,另外其空间信号图案还具有圆对称性,因此非常适合在空间带宽有限的远距离无线光通信中使用。     

Cross-Layer Energy-Efficiency Optimization of Packet Based Wireless MIMO Communication Systems

Energy in today’s short-range wireless communication is mostly spent on the analog- and digital hardware rather than on radiated power. Hence, purely information-theoretic considerations fail to achieve the lowest energy per information bit and the optimization process must carefully consider the overall transceiver. In this paper, we propose to perform cross-layer optimization, based on an energy-aware rate adaptation scheme combined with a physical layer that is able to properly adjust its processing effort to the data rate and the channel conditions to minimize the energy consumption per information bit. This energy proportional behavior is enabled by extending the classical system modes with additional configuration parameters at the various layers. Fine grained models of the power consumption of the hardware are developed to provide awareness of the physical layer capabilities to the medium access control layer. The joint application of the proposed energy-aware rate adaptation and modifications to the physical layer of an IEEE 802.11n system, improves energy-efficiency (averaged over many noise and channel realizations) in all considered scenarios by up to 44 %.     

Cross Layer Considerations for an Adaptive OFDM-Based Wireless Communication System

Future applications require high, but variable data rates and different quality of services (QoS) which is a real challenge for the communication system design. Additionally, the broadband radio channel can be assumed to be frequency selective and time variant, which means the transmission performance varies over time and frequency. The OFDM transmission technique is very flexible in adapting the transmission parameters to the current channel situation and to the application-specific requirements. This kind of flexibility will be applied to solve the technical tasks in the design procedures of future communication systems.Prof. Hermann Rohling received the Diplom Mathematiker degree from the Technical University Stuttgart, Germany in 1977 and the PhD from the Faculty of Electrical Engineering, Rheinisch-Westfälischen Technischen Hochschule (RWTH) Aachen, Germany in 1984. From 1977 to 1988 he was with the AEG Research Institute, Ulm as a researcher working in the area of digital signal processing for radar and communications applications. From 1988 to 1999 he was a Professor of Communications Engineering at the Technical University Braunschweig (TUBS). Since 1999, Professor Rohling is with the Technical University in Hamburg-Harburg (TUHH), Germany. His research interests include Wideband Mobile Communications especially based on Multicarrier Transmission Techniques (OFDM) for future broadband systems (4G), Wireless Local Loops, Multiple Access and channel coding schemes, Digital Radar Signal Processing especially for automotive radar applications, differential GPS for high precision navigation. Prof. Rohling is a member of ITG, DGON and a senior member of IEEE.Dr. RainerGrünheid studied Electrical Engineering at theTechnical University Braunschweig (TUBS), Germany, from 1989–1994. After receiving his Diploma degree, he pursued his Ph.D. at the Technical University Hamburg-Harburg (TUHH), Germany, until 2000. Currently, he is working as a research assistant at the Department of Telecommunications at TUHH. His research interests include mobile communications and multicarrier systems (OFDM), with a special emphasis on multiple access schemes, MAC protocols, link adaptation techniques and cross-layer design.     

无线宽带通信系统

本文重点介绍无线宽带通信系统的宽带接入技术如无线LAN、无线 ATM、LMDS 和MMDS。另外-还介绍了以 TD-MA 和 CDMA 为基础的多媒体无线通信中的新技术,如自适应调制、OFDM/SS 等。     

宽带无线通信系统演进中的安全技术方案及发展趋势

目本文分析了宽带无线通信系统演进中LTE和WiMAx所面临的安全威胁和安全需求,探讨了LTE和WiMAX网络安全技术机制,最后介绍了WiMAX与3GPP互通的安全技术发展趋势.