蜂窝移动通信系统中的定位技术

本文介绍了蜂窝移动通信系统中定位技术的展望、原理及分类，并详细分析了几种典型的定位技术以及当前标准化的情况，最后对定位技术的应用模式和应用前景进行了讨论。     

迅速发展中的蜂窝移动通信技术

蜂窝技术是移动通信中最重要的技术之一。本文通过对模拟蜂窝移动电话系统、数字蜂窝移动通信系统、码分多址数字蜂窝移动通信系统以及第三代移动通信系统发展过程的介绍和技术特性的比较，对未来全球移动通信的发展趋势以及市场进行了预测和展望。     

MIMO技术在无线通信系统中的应用

多入多出(MIMO：Multiple-Input Multiple-Output)技术相对于传统的单天线系统，能够大大提高系统容量和频谱利用率，使得系统能在有限的无线频带下传输更高速率的数据业务。简要介绍了无线通信中MIMO技术的发展现状、研究热点及应用。     

关于移动通信系统中蜂窝的几个概念

目前的移动通信系统一般采用小区制,即将整个网络服务区域划分为若干小区,每个小区分别设有一个（或多个）基站,用以负责本小区移动通信的联络和控制等功能。因此移动网络的覆盖区可以看成是由若干正六边形的无线小区相互邻接而构成的面状服务区。由于这种服务区的形状很像蜂窝,我们便将这种系统称之为蜂窝式移动通信系统,与之相对应的网络称之为蜂窝式网络。宏蜂窝小区传统的蜂窝式网络由宏蜂窝小区（ｍａｃｒｏｃｅｌｌ）构成,每小区的覆盖半径大多为１ｋｍ～２５ｋｍ。由于覆盖半径较大,所以基站的发射功率较强,一般在１０Ｗ以…     

超宽带无线通信与声表面波宽带信号处理技术

介绍了超宽带(UWB)无线通信的技术及特点,与传统窄带无线系统进行了性能比较,指出了超宽带无线通信四大关键技术是:超宽带无线通信脉冲信号的波形设计;超宽带无线通信脉冲信号编码与调制方式;超宽带无线通信信号的检测;超宽带无线通信系统中的同步捕获技术;分析了超宽带尤线通信系统军用的潜在市场,最后阐述了SAW宽带信号处理技术在UWB通信系统中的应用.     

无线通信中的空时编码技术

空时编码技术是抗信道衰落和提高系统容量的一种最新编码方法，这里简介了三种典型空时码：分层空时码、空时格型码和空时分组码，比较了它们的优缺点，并分析了下一代通信中空时编码的发展方向。     

无线通信系统中的低码率空时网格码

空时网格编码能在频带利用率、分集增益、调制方式与编码网络图复杂度之间达到最佳的折衷。本文给出了几种低码率空时网格码的好码。理论分析和系统仿真表明,在相同的频带利用率下,该空时网格码可具有比空时块码级联卷积码具有更好的误码率性能,更适合于对频带利用率要求不高的功率受限无线通信系统。     

无线通信网络

无线通信是用电磁波通信的方式．它突破了有线通信对收、发端地理位置固定的束缚．拓展了人们的通信范围。生活中应用最多的无线通信是蜂窝移动通信系统和无线宽带接入系统。它们为人们提供了内容丰富的业务．其发展改变了人们日常的通信方式。     

智能天线及其在无线通信中的应用

本文全面地阐述了智能天线的概念，特点，实现方案和应用前景，同时还给出了智能天线的最新发展动态。     

CDMA系统中的蜂窝技术

本文讨论了CDMA系统中蜂窝技术的特点，介绍了几种典型的蜂窝技术。分析指出CDMA蜂窝系统是实现大容量、高性能和一致覆盖的个人移动通信网的较佳选择。     

蜂窝通信的空分多址:概念、算法和性能

蜂窝通信采用空分多址正在移动通信领域引起广泛关注。本文对空分多址的基本概念、空间信道模型及其知识利用、上下行链路的实现方法和算法、以及对系统性能的改善等诸方面,进行了比较全面的论述。对目前空分多址研究中值得关注的问题,表达了作者的观点。     

COD: Diversity-Adaptive Subspace Processing for Multipath Separation and Signal Recovery

This paper proposes a generalized multipath separability condition for subspace processing and derives a novel COD (Combined Oversampling and Displacement) algorithm to utilize both spatial and temporal diversities for path separation, DOA (Direction of Arrival) estimation and signal recovery. A unique advantage lies in its ability to cope with the situation where the number of multipaths is larger than that of antenna elements, which has not been treated in the traditional approaches. COD strategy solves the antenna deficiency problem by combining vertical expansion with temporal oversampling and horizontal expansion with spatial displacement. We provide a detailed analysis on the theoretical footings for COD factorization and multipath separability conditions, which naturally leads to COD path separation and DOA estimation algorithms. Another advantage of COD factorization hinges upon its ability to generate a multiplicity of eigenvalues which greatly facilitates a SIMO channel equalization formulation useful for signal recovery. This paper also proposes a frequency-domain total-least-square algorithm for SIMO equalization procedure. Finally, simulation results on path separation, DOA estimation and signal recovery are demonstrated.     

雷达侦察抗反射信号处理技术

针对多路径反射引起的信号处理增批,提出了一种改进算法。该算法利用直射信号和反射信号脉冲序列的完整性和出现概率的不同,能有效区分反射信号和不同方位的同型雷达信号,在消除反射信号的同时,避免了对不同方位同型雷达的漏警。     

GPS自适应调零天线信号处理系统硬件设计

针对GPS抗干扰问题,常用手段是在信号处理系统中采用自适应调零算法来实现抗干扰。结合该算法文中给出了一种信号处理系统的硬件实现方案。首先概述GPS自适应调零天线的系统结构,然后给出信号处理系统的硬件设计思路及其功能模块的实现,最后通过实测数据验证硬件模块可以满足自适应调零算法的要求。     

New Paradigms in Wireless Communication Systems

This paper discusses what a new paradigm can be in wireless communication systems of the twenty-first century. First, it suggests two directions for the new paradigm; one is “micro- and nano-device communication system” which is the projected scenario considering that the entities in source and destination have been shrinking throughout the history of wireless communication systems. The second direction is “networked robot system”, which emerges as a natural extension of mobile ad hoc networking where the networking is closely related to motion control of robots. Secondly, it shows two interesting research topics, “the new communication protocol design” and “signal processing”, respectively, that arise in the wake of the fusion between the two directions in the novel communication paradigm. Finally, it considers a new science of wireless communications in the twenty-first century. Shinsuke Hara received the B.Eng., M.Eng. and Ph.D. degrees in communications engineering from Osaka University, Osaka, Japan, in 1985, 1987 and 1990, respectively. From April 1990 to March 1997, he was an assistant professor in the Department of Communication Engineering, School of Engineering, Osaka University, and from October 1997 to September 2005, he was an associate professor in the Department of Electronic, Information and Energy Engineering, Graduate School of Engineering, Osaka University. Since October 2005, he has been a professor in the Department of Physical Electronics and Informatics, Graduate School of Engineering, Osaka City University. In addition, from April 1995 to March 1996, he was a visiting scientist at Telecommunications and Traffic Control Systems Group, Delft University of Technology, Delft, The Netherlands. His research interests include wireless communications systems and digital signal processing. Hiroyuki Yomo received B.S. degree in communication engineering from Department of Communication Engineering, Osaka University, Osaka, Japan, in 1997, and M.S. and Ph.D. degrees in communication engineering from Department of Electronic, Information, and Energy Engineering, Graduate School of Engineering, Osaka University, Osaka Japan, in 1999 and 2002, respectively. From April 2002 to March 2004, he was a Post-doctoral Fellow in Department of Communication Technology, Aalborg University, Denmark. From April 2004 to September 2004, he was at Internet System Laboratory, NEC Corporation, Japan. Since October 2004, he has been an Assistant Research Professor in Center for TeleInfrastructure (CTIF), Aalborg University, Denmark. His main research interests are access technologies, radio resource management, and link-layer techniques in the area of short-range communication, cellular network, cognitive radio, and sensor network. Petar Popovski received the Dipl.-Ing. in electrical engineering and M.Sc. in communication engineering from the Faculty of Electrical Engineering, Sts. Cyril and Methodius University, Skopje, Republic of Macedonia, in 1997 and 2000, respectively. He received a Ph.D. degree from Aalborg University, Denmark, in 2004. From 1998 to 2001 he was a teaching and research assistant at the Institute of Telecommunications, Faculty of Electrical Engineering in Skopje. He is currently Assistant Professor at the Department of Communication Technology at the Aalborg University. His research interests are related to the PHY-MAC aspects of wireless protocols, wireless sensor networks, random access protocols, and network coding. Kazunori Hayashi received the B.E., M.E. and Ph.D. degrees in communication engineering from Osaka University, Osaka, Japan, in 1997, 1999 and 2002, respectively. He spent 3 months in 2000 at Aalborg University, Denmark, as a Visiting Scholar. Since 2002, he has been with the Department of Systems Science, Graduate School of Informatics, Kyoto University. He is currently an Assistant Professor there. His research interests include digital signal processing for communications systems.     

自适应信号处理技术的应用

自适应信号处理技术在雷达、通信、声纳、图像处理、计算机视觉、地震勘探、生物医学、振动工程等领域有着极其重要的应用。目前这门新学科仍在继续向纵深方向迅速发展,特别是盲自适应信号处理和利用神经网络进行的非线性自适应信号处理。对于实现智能信息处理系统有很好的应用前景。介绍了自适应信号处理技术在滤波、系统辨识、自适应均衡、回波抵消、谱估计、谱线增强、自适应波束形成等方面的应用,并介绍了其发展前景。     

CDMA中智能天线的接收准则及自适应算法研究

在ＣＤＭＡ基站中采用自适应天线阵列可以降低多址干扰，提高系统容量，本文提出了一种适合于移动无线通信环境下的接收准则，最大接收信号准则，并根据该准则提出了空间变步长搜索算法。最后分析了基站采用自适应天线阵列时反向信道容量，与使用无方向天线相比，大大增加了系统容量。     

天基电子侦测中的阵列信号处理技术

随着应用需求和科学技术的发展,电子侦察卫星的星上处理能力日益增强。以微弱信号截获、同频多信号侦察、高分辨测向、高精度定位为出发点,分析了天基电子侦测中的阵列信号处理技术,并针对有效载荷的特殊要求进行专门设计。通过利用天线阵列几何结构综合、数字波束形成、空间谱估计测向、基于多次测量数据的最优化处理方法,可以实现快速侦察、目标信号提取和精确定位。     

Q值对无源压力传感器无线信号传输的影响

主要研究了无源压力传感器的无线信号传输性能。传感器结构由压力敏感电容空腔和电感天线组成,内部无需有源器件、电池等。通过压力敏感结构电感天线的金属层厚度、线宽等因素的改变来研究无线信号传输性能。经过实验测试,电感的品质因数Q对传感器的信号传输是有影响的。电感天线的金属层加厚、线宽加宽,可以减小电感的电阻,从而增大传感器电感的Q值,有利于无线信号的传输。     

铁路旅客列车无线公用电话应用技术

据不完全统计,全国铁路每年有超过10亿人/次的客运流量,铁路列车作为运输旅客的载体蕴藏着一个潜在的、亟待开发的巨大通信市场。开发这个市场,为旅客在出行途中提供商用级的电信服务,一直是铁道部领导重视以及中国铁通探讨和研究的课题。本文对无线公用电话在旅客列车上的成功应用进行了深入研究。