检索结果-内蒙古大学图书馆

Reliability improvement techniques for HomeRF system

IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2003年第2期49卷 321-327页

作者： Cho, JH Song, HK Sejong Univ Dept Informat & Commun Engn Seoul South Korea

In this paper, we propose several techniques for the HomeRF system. A DC-offset compensation technique and a decision directed channel estimation technique are proposed. Because they use a TS field as reference information for initial training, the proposed techniques require no additional training sequence and only a little additional complexity. And finally, turbo coding technique and space-time block coding technique are considered as improved coding schemes. According to the results of our simulations, the performances of the proposed techniques are significantly improved in comparison with the conventional HomeRF system.

关键词： channel estimation DC-offset compensation space-time block coding turbo coding

来源：评论

学校读者我要写书评

暂无评论

A STBC interference cancellation site diversity technique for a PB/MC-CDMA downlink

引用

IETE JOURNAL OF RESEARCH 2013年第4期59卷 319-325页

作者： Li, Changping Lee, Kyujin Cho, Juphil Lee, Kyesan Kyung Hee Univ Dept Elect & Radio Engn Suwon South Korea Semyung Univ Dept Elect Engn Jecheon South Korea Kunsan Natl Univ Sch Elect & Informat Engn Kunsan South Korea

It has been proved that site diversity is an effective technique to improve the bit error rate (BER) performance for users located at the cell edge. In this paper, the downlink site diversity is applied to a partial block multicarrier-CDMA (PB/MC-CDMA) system, which is a newly proposed and more flexible system compared to the well-known multicarrier CDMA (MC-CDMA) system. We propose a space-time block coding with interference cancellation (STBC-IC) site diversity scheme, where the STBC is adopted on the site diversity participant base stations. A joint code assignment enables the mobile users to get full diversity and reduce inter-cell interference, whereas IC eliminates the intra-cell interference from the users that use the same partial block as the desired user. The BER performances using site diversity, STBC site diversity, and the proposed STBC-IC site diversity in PB system are evaluated by computer simulations. The results show that the site diversity technique works well in the PB system for users close to the cell edge. With the proposed STBC-IC site diversity scheme, we can expect satisfying BER and throughput results.

关键词： Interference cancellation Partial block multicarrier-code division multiple access system Site diversity space-time block coding

来源：评论

学校读者我要写书评

暂无评论

A Novel Filter-Bank Multicarrier Scheme to Mitigate the Intrinsic Interference: Application to MIMO Systems

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2012年第3期11卷 1112-1123页

作者： Zakaria, Rostom Le Ruyet, Didier CNAM CEDRIC LAETITIA Lab F-75141 Paris France

Filter-bank multicarrier (FBMC) transmission system was proposed as an alternative approach to orthogonal frequency division multiplexing (OFDM) system since it has a higher spectral efficiency. One of the characteristics of FBMC is that the demodulated transmitted symbols are accompanied by interference terms caused by the neighboring transmitted data in time-frequency domain. The presence of this interference is an issue for some multiple-input multiple-output (MIMO) schemes and until today their combination with FBMC remains an open problem. We can cite, among these techniques, the Alamouti scheme and the maximum likelihood detection (MLD) with spatial multiplexing (SM). In this paper, we shall propose a new FBMC scheme and transmission strategy in order to avoid this interference term. This proposed scheme (called FFT-FBMC) transforms the FBMC system into an equivalent system formulated as OFDM regardless of some residual interference. Thus, any OFDM transmission technique can be performed straightforwardly to the proposed FBMC scheme with a corresponding complexity growth compared to the classical FBMC. First, we will develop the FFT-FBMC in the case of single-input single-output (SISO) configuration. Then, we extend its application to SM-MIMO configuration with MLD and Alamouti coding scheme. Simulation results show that FFT-FBMC can almost reach the OFDM performance, but it remains slightly outperformed by OFDM.

关键词： Filter-bank multicarrier FBMC MIMO maximum likelihood detection MLD OFDM/OQAM spatial multiplexing space-time block coding

来源：评论

学校读者我要写书评

暂无评论

Area, speed and power measurements of FPGA-based complex orthogonal space-time block code channel encoders

引用

INTERNATIONAL JOURNAL OF ELECTRONICS 2010年第1期97卷 31-43页

作者： Passas, Georgios Freear, Steven Fawcett, Darren Univ Leeds Sch Elect & Elect Engn Leeds W Yorkshire England Pace Plc Saltaire W Yorkshire England

space-time coding (STC) is an important milestone in modern wireless communications. In this technique, more copies of the same signal are transmitted through different antennas (space) and different symbol periods (time), to improve the robustness of a wireless system by increasing its diversity gain. STCs are channel coding algorithms that can be readily implemented on a field programmable gate array (FPGA) device. This work provides some figures for the amount of required FPGA hardware resources, the speed that the algorithms can operate and the power consumption requirements of a space-time block code (STBC) encoder. Seven encoder very high-speed integrated circuit hardware description language (VHDL) designs have been coded, synthesised and tested. Each design realises a complex orthogonal space-time block code with a different transmission matrix. All VHDL designs are parameterisable in terms of sample precision. Precisions ranging from 4 bits to 32 bits have been synthesised. Alamouti's STBC encoder design [Alamouti, S. M. (1998), 'A Simple Transmit Diversity Technique for Wireless Communications', IEEE Journal on Selected Areas in Communications, 16: 55-108.] proved to be the best trade-off, since it is on average 3.2 times smaller, 1.5 times faster and requires slightly less power than the next best trade-off in the comparison, which is a 3/4-rate full-diversity 3Tx-antenna STBC.

关键词： channel coding space-time block coding orthogonal codes VHDL design FPGA implementation

来源：评论

学校读者我要写书评

暂无评论

Blind and semi-blind ML detection for space-time block-coded OFDM wireless systems

引用

EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2014年第1期2014卷 1-14页

作者： Zaib, Alam Al-Naffouri, Tareq Y. King Fahd Univ Petr & Minerals Dept Elect Engn Dhahran 31261 Saudi Arabia King Abdullah Univ Sci & Technol Dept Elect Engn Thuwal 239556900 Saudi Arabia

This paper investigates the joint maximum likelihood (ML) data detection and channel estimation problem for Alamouti space-time block-coded (STBC) orthogonal frequency-division multiplexing (OFDM) wireless systems. The joint ML estimation and data detection is generally considered a hard combinatorial optimization problem. We propose an efficient low-complexity algorithm based on branch-estimate-bound strategy that renders exact joint ML solution. However, the computational complexity of blind algorithm becomes critical at low signal-to-noise ratio (SNR) as the number of OFDM carriers and constellation size are increased especially in multiple-antenna systems. To overcome this problem, a semi-blind algorithm based on a new framework for reducing the complexity is proposed by relying on subcarrier reordering and decoding the carriers with different levels of confidence using a suitable reliability criterion. In addition, it is shown that by utilizing the inherent structure of Alamouti coding, the estimation performance improvement or the complexity reduction can be achieved. The proposed algorithms can reliably track the wireless Rayleigh fading channel without requiring any channel statistics. Simulation results presented against the perfect coherent detection demonstrate the effectiveness of blind and semi-blind algorithms over frequency-selective channels with different fading characteristics.

关键词： Blind ML detection OFDM space-time block coding

来源：评论

学校读者我要写书评

暂无评论

space-time Processing for X Channels Using Precoders

引用

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2012年第4期60卷 1849-1861页

作者： Li, Feng Jafarkhani, Hamid Univ Calif Irvine Ctr Pervas Commun & Comp Irvine CA 92664 USA

In this paper, we investigate how to send space-time codes with full diversity and low decoding complexity for X channels using precoders. First, we assume that we have 2 transmitters and 2 receivers. Each transmitter sends different codewords to each receiver at the same time. We propose an orthogonal transmission scheme that combines space-time block coding and array processing to achieve low-complexity decoding and full diversity for transmitted signals. To our best knowledge, this is the first scheme which can achieve low-complexity decoding and full diversity for any transmitted codeword in X channel when all the users transmit at the same time. Finally, we show that under certain conditions, our proposed scheme can be extended to a general case with any number of transmitters and receivers each with any number of antennas. Simulation results validate our theoretical analysis.

关键词： Array processing full diversity interference cancellation precoder design space-time block coding X channels

来源：评论

学校读者我要写书评

暂无评论

Frequency-Domain Equalization for Orthogonal and Quasi-Orthogonal STBCs over Frequency-Selective Wireless and Power-Line Channels

引用

WIRELESS PERSONAL COMMUNICATIONS 2013年第4期71卷 2445-2461页

作者： Sheikh-Hosseini, Mohsen Molavi-Kakhki, Mohammad Hodtani, Ghosheh Abed Ferdowsi Univ Mashhad Dept Elect Engn Program Commun Engn Mashhad Iran Ferdowsi Univ Mashhad Dept Elect Engn Mashhad Iran

In recent years, combination of single-carrier frequency-domain equalization (SC-FDE) and space-time block coding/code (STBC) techniques to exploit the advantages of both, has received a great attention. In this paper we propose new techniques for combining SC-FDE with orthogonal and Quasi-orthogonal STBCs applicable to any number of transmit antennas. For Quasi-orthogonal STBC we first propose a new structure for codes with four transmit antennas and then extend it to higher numbers. We convert Quasi-orthogonal system to two equivalent orthogonal subsystems and equalize and decode these subsystems based on our proposed procedure for orthogonal codes. Finally, we present our simulation results for different frequency-selective wireless and power-line channels and show that a significant SNR gain is achieved when SC-FDE is combined with diversity techniques.

关键词： Frequency-selective fading channels Power line communication space-time block coding Single-carrier frequency-domain equalization

来源：评论

学校读者我要写书评

暂无评论

Unitary Precolders for ST-OFDM Systems Using Alamouti STBC

引用

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS 2008年第9期55卷 2860-2869页

作者： Chung, Yuan-Hwui Phoong, See-May Natl Taiwan Univ Dept Elect Engn Taipei 106 Taiwan Natl Taiwan Univ Grad Inst Commun Engn Taipei 106 Taiwan

This paper studies unitary precoders for space-time coded orthogonal frequency division multiplexing (ST-OFDM) systems using Alamouti space-time block codes (STBC). We consider two channel models: 1) the LTI case where the channels are invariant for two consecutive OFDM blocks;2) the time-varying case where the channels are invariant within one OFDM block but they vary slightly between two OFDM blocks. For the LTI case, we derive the optimal precoder for QPSK modulation. It is shown that the optimal precoder is channel independent and can greatly enhance the performance of the ST-OFDM system. For the time-varying case, the channel variation will cause inter-carrier interference (ICI) in the ST-OFDM system and can result in serious performance degradation. We will show that by properly designing the precoder, we can average the output error variance and hence greatly alleviate the ICI effect. As a result, the bit error rate (BER) performance can be significantly improved.

关键词： space-time block coding equalization precoding OFDM

来源：评论

学校读者我要写书评

暂无评论

Cross-layer in MIMO-OFDM System with Adaptive Modulation and coding:Design and Analysis

引用

Chinese Journal of Electronics 2014年第2期23卷 371-376页

作者： ZHAO Junhui GUAN Xin LI Xiuping ZENG Longji State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University National Mobile Communications Research Laboratory Southeast University Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences School of Electronic Engineering Beijing University of Posts and Telecommunications

The queuing performance of the cross-layer system with space-time block code(STBC) over Multiinput-multi-output(MIMO) channel is analyzed. The Adaptive modulation and coding(AMC) in physical layer and finite length of buffer in data-link layer are combined with this model. A simple cross-layer design and the queue state process are proposed based on finite state Markov channel model, which is to solve the service process. The proposed cross-layer design is also incorporated with STBC to further improve the system performance. Simulation results illustrate the dependence of system performance on various parameters, and quantify the performance gain due to cross-layer optimization. The adjustment of target packet loss rate of adaptive modulation coding in physical layer can maximize average throughput of the system,meanwhile a significant improvement of the system performance is brought.

关键词： Adaptive modulation and coding Crosslayer design Multi-input-multi-output space-time block coding

来源：评论

学校读者我要写书评

暂无评论

Nonblind and semiblind space-time-frequency multiuser detection for space-time block-coded MC-CDMA

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2005年第4期4卷 1311-1318页

作者： Li, ZX Latva-aho, M Univ Oulu Ctr Wireless Commun Oulu Finland

In this paper, a novel space-time-frequency minimum mean squared error (STF-MMSE)-based parallel interference cancellation receiver is proposed for space-time block-coded multicarrier code division multiple access systems in time-varying fading channels. The, signal processing of this new detector is jointly implemented in space, time, and frequency domains, which leads to a powerful capability of combating interference coming from different sources. An adaptive implementation based on subspace estimation is proposed for slow-varying fading channels. Furthermore, based on the characteristic function of a complex Gaussian random vector, an analytical method to calculate the bit error probability of the proposed STF-NMSE receiver is presented. Representative examples of the detector are provided to demonstrate its superior performance.

关键词： fading channels multicarrier CDMA multiuser detection space-time block coding

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：