检索结果-内蒙古大学图书馆

Impact of transmit antenna spacing on 2 x 1 alamouti radio transmission

ELECTRONICS LETTERS 2007年第4期43卷 198-199页

作者： Caban, S. Rupp, M. Vienna Univ Technol Inst Commun & Radiofrequency Engn A-1040 Vienna Austria

It is a common belief that multiple transmit antennas have to be placed far apart in order to avoid undesired effects such as mutual coupling, changing beampatterns, antenna mismatching losses, and correlation. The following radio communication setup is considered: two lambda/4-monopole ground-plane transmit antennas, a single receive antenna, 4QAM modulation, alamouti space-time coding, uncoded single carrier transmission at 2.4 GHz, indoor scenario. By measurements, the impact of very low transmit antenna spacing on the average uncoded BER over transmit-power performance of such a radio link, therefore accounting for all losses in the transmission chain, is examined. The common belief that multiple transmit antennas have to be placed far apart cannot be confirmed.

关键词： antenna radiation patterns multiple transmit antennas error statistics transmitting antennas antenna arrays alamouti space time coding radio link UHF antennas transmit antenna spacing single carrier transmission 4QAM modulation ground plane transmit antennas Antenna arrays 2.4 GHz Other topics in statistics radio links radio communication alamouti radio transmission Radio links and equipment single receive antenna

来源：评论

学校读者我要写书评

暂无评论

Enhanced Cooperative coding for Relay-Based MIMO-OFDM Systems

Enhanced Cooperative Coding for Relay-Based MIMO-OFDM System...

引用

21st Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Abualhaol, Ibrahim Y. Matalgah, Mustafa M. Abu-Abed, Alaeddin S. Khalifa Univ Sci Technol & Res Sharjah U Arab Emirates Univ Mississippi University MS 38677 USA Univ Cent Oklahoma Edmond OK 73034 USA

ISBN: (纸本)9781424480166

In this paper, we propose a 2 x 2 cooperative multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) scheme based on alamouti space-time coding. In this scheme, the the relay and the destination antennas receive the transmitted symbols from the source during the first stage. Then, both the relay and the destination generate their own decision variables using an alamouti decoding procedure by the end of the first stage. In the second stage, the relay sends its own decision variables to the destination to enhance the destination decision variables and therefore improves the performance of the system. Our results show the superiority of the proposed cooperative alamouti scheme by improving the system performance in terms of average BER, frame error rate (FER), and spectral efficiency.

关键词： alamouti space time coding BER MIMO communication OFDM modulation cooperative alamouti scheme cooperative coding cooperative communication cooperative multiple input multiple output system error statistics frame error rate orthogonal frequency division multiplexing receiving antennas relay-based MIMO-OFDM system relays space-time codes spectral efficiency transmitting antennas

来源：评论

学校读者我要写书评

暂无评论

Enhancing the performance of MIMO systems in a typical mobile radio environment

Enhancing the performance of MIMO systems in a typical mobil...

引用

IEEE International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET)

作者： Bhageerath, Y. V. Sai Rao, Sri. Amara Prakasa Natl Inst Technol Dept Elect & Commun Engn Warangal Andhra Pradesh India

ISBN: (纸本)9781467393379

This paper presents various challenges faced in modern wireless communications and how these challenges are overcome by using Multiple Input and Multiple Output (MIMO) systems. Analysis of various equalization techniques such as Zero Forcing (ZF) equalization, Minimum Mean Square Equalization (MMSE), Maximum Likelihood (ML) equalization and Maximum Ratio Combining (MRC) in a 2x2 MIMO system are shown. Among these techniques Maximum ratio combining technique provides better performance. In this paper a new scheme is proposed which uses alamouti space time block coding at the transmitting section and Maximum ratio combining at the receiving section which provides best performance among all the equalization techniques. Simulation results are also provided.

关键词： Multipath Rayleigh fading Binary phase shift keying(BPSK) Transmit diversity Receive diversity alamouti space time coding Maximum ratio combining(MRC)

来源：评论

学校读者我要写书评

暂无评论

On Opportunistic Power Control for MIMO-OFDM Systems

On Opportunistic Power Control for MIMO-OFDM Systems

引用

Globecom Workshops

作者： Reider, Norbert Fodor, Gabor Budapest Univ Technol & Econ Dept Telecommun & Media Informat Budapest Hungary Ericsson Res SE-16480 Stockholm Sweden

ISBN: (纸本)9781424488650

When fast and accurate channel state information (CSI) at the transmitter is available, opportunistic power control (OPC) is an attractive alternative to signal-to-interference-and-noise ratio (SINR) target following approaches, because it maximizes throughput by taking advantage of fast channel variations. On the other hand, in multiple-input multiple-output (MIMO) systems, open loop schemes such as alamouti space time coding and spatial multiplexing (SM) exploit channel diversity without accurate CSI. In an attempt to answer the question whether OPC is worth the pain of obtaining fast CSI, in this paper we evaluate the gains of OPC for the downlink of a system employing MIMO with alamouti and SM. We formulate the OPC problem as a throughput maximization task subject to a power budget and fairness constraints. We solve this task by the Augmented Lagrangian Penalty Function (ALPF) and find that without fairness constraints, OPC in concert with SM provides superior throughput. With tight fairness constraint, alamouti along with equal power allocation becomes a viable alternative to the SM OPC scheme.

关键词： alamouti space time coding MIMO communication MIMO-OFDM systems OFDM modulation augmented Lagrangian penalty function channel diversity channel state information diversity reception fairness constraints multiple-input multiple-output systems open loop ope

来源：评论

学校读者我要写书评

暂无评论

Evaluation of diversity techniques for the indoor diffuse infrared channel

Evaluation of diversity techniques for the indoor diffuse in...

引用

IEEE Wireless Communications and Networking Conference

作者： Tacconi, David Woesner, Hagen Chlamtac, Imrich Xie, Changsong CREATE NET Via Solteri 38 I-38100 Trento Italy Siemens CT ONT D-81730 Munich Germany

ISBN: (纸本)9781424406586

Infrared communication has been recently reconsidered as an alternative to microwave radio used by WLAN devices, suitable for specific applications such as hospitals or industrial communication in the presence of strong electromagnetic fields. The design of a system able to communicate efficiently even without Line Of Sight (LOS) and in the presence of fading represents a challenging issue for a wider utilization of IR. The growing interest in the field of radio communication towards MIMO systems has encouraged few researchers to use similar techniques to fight fading effects of the diffuse infrared channel. As a first step in the design of an infrared node for diffuse communication we developed a complete simulation framework to evaluate the performance of diversity techniques for IR. We also introduce a blind channel estimator for IR MIMO receivers. Results show that diversity leads to consistent performance improvements for the IR channel in the presence of fading.

关键词： wireless optical communication diffuse infrared channel alamouti space time coding channel estimation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：