检索结果-内蒙古大学图书馆

On space-time coding for Free-space Optical Systems

IEEE TRANSACTIONS ON COMMUNICATIONS 2010年第1期58卷 58-62页

作者： Bayaki, Ehsan Schober, Robert Univ British Columbia Dept Elect & Comp Engn Vancouver BC V6T 1Z4 Canada

Atmospheric turbulence-induced fading is one of the main impairments affecting free-space optics (FSO) communications. In this paper, we consider FSO systems with intensity modulation and direct detection (IM/DD) and derive a closed-form expression for the asymptotic pairwise error probability of general FSO space-time codes (STCs) for two lasers and an arbitrary number of photodetectors for channels suffering from Gamma-Gamma fading. Furthermore, we provide a simple design criterion for FSO STCs which is used to establish the quasi-optimality of previously proposed FSO repetition codes. We also show that STCs optimized for RF systems achieve full diversity in FSO systems but are suboptimal as far as the coding gain is concerned. Simulation results confirm the analytical findings of this paper.

关键词： space-time coding free-space optical systems intensity modulation and direct detection gamma-gamma fading repetition coding

来源：评论

学校读者我要写书评

暂无评论

On a hybrid beamforming/space-time coding scheme

引用

IEEE COMMUNICATIONS LETTERS 2004年第1期8卷 15-17页

作者： Li, P Zhang, LR So, HC City Univ Hong Kong Dept Elect Engn Kowloon Hong Kong Peoples R China Xidian Univ Key Lab Radar Signal Proc Xian 710071 Peoples R China City Univ Hong Kong Dept Comp Engn & Informat Technol Kowloon Hong Kong Peoples R China

A multiple transmit antenna system based on hybrid beamforming and space-time coding technologies is examined. The reduction factor of the required transmitted energy achievable by the use of hybrid scheme is quantified for any given outage capacity. We show that although a sole space-time coding configuration is superior asymptotically (i.e., for extremely low outage requirements), a hybrid beamforming/space-time coding configuration can be a more effective solution for modest outage requirements. It may provide a useful design guideline for wireless systems, especially for the downlink where multiple transmit antenna scheme is feasible.

关键词： beamforming smart antennas space-time coding transmit diversity

来源：评论

学校读者我要写书评

暂无评论

Combining space-time coding and adaptive sectorization using reflectarrays

引用

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2006年第0期5卷 298-301页

作者： Messier, Geoffrey G. Hum, Sean V. Okoniewski, Michal Univ Calgary Dept Elect & Comp Engn Calgary AB Canada

This letter presents a new code-division multiple-access (CDMA) system architecture that combines space-time block code (STBC) transmission and adaptive sectorization using electronically tunable reflectarrays. The result is a single base station architecture that can use a combination of diversity and spatial division transmission in order to achieve good performance in a wide range of environments. The reflectarray method has the further advantage of implementing both STBC and adaptive sectorization using a single transmit chain and power amplifier. This significantly reduces the cost of deploying a multiple antenna scheme and makes it possible to retrofit combined STBC/adaptive sectorization transmission to existing single antenna base stations already in the field.

关键词： code-division multiple-access (CDMA) error vector magnitude reflectarrays space-time coding

来源：评论

学校读者我要写书评

暂无评论

MIMO space-time coding for diffuse optical communication

引用

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2006年第6期48卷 1108-1110页

作者： Garfield, M Liang, C Kurzweg, TP Dandekar, KR Drexel Univ Dept Elect & Comp Engn Philadelphia PA 19104 USA

A multiple input, multiple output (MIMO) diffiuse optical communications link is implemented and evaluated using a 2 X 2 Alamouti-type, space-time coding scheme to increase link performance beyond that of single input, single output (SISO) and multiple input, single output (MISO) systems. We present a representative profile of received power versus distance, and comparative bit-error probability performance. (c) 2006 Wiley Periodicals, Inc.

关键词： MIMO diffuse optics space-time coding infrared communications free-space optics

来源：评论

学校读者我要写书评

暂无评论

Noncoherent detection of orthogonal modulation combined with Alamouti space-time coding

引用

JOURNAL OF COMMUNICATIONS AND NETWORKS 2003年第2期5卷 124-134页

作者： Simon, MK Wang, JB CALTECH Jet Prop Lab Pasadena CA USA Univ Calif Los Angeles Dept Elect Engn Los Angeles CA 90024 USA

In this paper, we investigate the error probability performance of noncoherently detected orthogonal modulation combined with Alamouti space-time block coding. We find that there are two types of pair-wise error probabilities that characterize the performance. We employ methods that allow a direct evaluation of exact, closed-form expressions for these error probabilities. Theoretical as well as numerical results show that noncoherent orthogonal modulation combined with space-time block coding (STBC) achieves full spatial diversity. We derive an expression for approximate average bit error probability for M-ary orthogonal signaling that allows one to show the tradeoff between increased rate and performance degradation.

关键词： digital communications fading channels noncoherent detection space-time coding

来源：评论

学校读者我要写书评

暂无评论

Alamouti-type space-time coding for free-space optical communication with direct detection

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2005年第1期4卷 35-39页

作者： Simon, MK Vilnrotter, VA CALTECH Jet Prop Lab Pasadena CA 91109 USA

A modification of the Alamouti code originally proposed for RF wireless applications is described that allows it to be applied in scenarios such as free-space optical communication with direct detection where unipolar modulations like pulse-position modulation and ON-OFF keying are traditionally used to convey the information. The modification of the code and associated decision metric is such as to maintain all of the desirable properties of the original scheme.

关键词： direct detection optical communications space-time coding

来源：评论

学校读者我要写书评

暂无评论

Full-diversity full-rate complex-field space-time coding

引用

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2003年第11期51卷 2917-2930页

作者： Ma, XL Giannakis, GB Auburn Univ Dept Elect & Comp Engn Auburn AL 36849 USA Univ Minnesota Dept Elect & Comp Engn Minneapolis MN 55455 USA

Exciting recent developments in wireless multiantenna communications have led to designs aiming mainly at. one of two objectives: either high-performance by enabling the diversity provided by multi-input multi-output (MIMO) channels or high-rates by capitalizing on space-time multiplexing gains to realize the high capacity of MIMO fading channels. By concatenating a linear complex-field coder (a.k.a. linear precoder) with a layered space-time mapper, we design systems capable of achieving both goals: full-diversity and full-rate (FDFR), with any number of transmit- and receive-antennas. We develop FDFR designs not only for flat-fading but for frequency-selective, or, time-selective fading MIMO channels as well. Furthermore, we establish the flexibility of our FDFR designs in striking desirable performance-rate-complexity tradeoffs. Our theoretical claims are confirmed by simulations.

关键词： capacity diversity frequency-selective channels linear complex-field coding OFDM outage probability performance space-time coding time-selective wireless fading channels

来源：评论

学校读者我要写书评

暂无评论

Concatenation of space-time coding and FEC for Few-Mode Fiber Systems

引用

IEEE PHOTONICS TECHNOLOGY LETTERS 2017年第7期29卷 603-606页

作者： Amhoud, El-Mehdi Rekaya-Ben Othman, Ghaya Jaouen, Yves TELECOM ParisTech F-75013 Paris France

space-division multiplexing (SDM) is becoming essential to increase the capacity of future optical communication systems. Propagating modes through multimode fibers are affected by a non-unitary crosstalk known as mode dependent loss (MDL), that requires either optical or digital signal processing solutions to be reduced. space-time (ST) coding designed and used for wireless communications was proved to be efficient to reduce polarization-dependent loss in PolMux systems and MDL in SDM systems. In this letter, we study a complete transmission scheme, including forward error correction (FEC) and ST coding. FEC is used to protect the transmission from errors, but in the presence of MDL, system's performance is reduced. We show by simulations and error probability derivation that coding gain summation is obtained, which makes both codes essential for the next generation of optical transmission systems.

关键词： Mode dependent loss space-time coding MIMO SDM forwar error correcting error probability optical fiber communication

来源：评论

学校读者我要写书评

暂无评论

Performance evaluation and analysis of space-time coding in unequalized multipath fading links

引用

IEEE TRANSACTIONS ON COMMUNICATIONS 2000年第11期48卷 1778-1782页

作者： Gong, Y Ben Letaief, K Hong Kong Univ Sci & Technol Dept Elect & Elect Engn Kowloon Hong Kong Peoples R China

This paper investigates the use of space-time (ST) coding for high-speed data transmission, as well as studies the effect of time delay spread on such scheme over unequalized fading channels. Using a random variable decomposition technique, we present an analytical model and obtain an approximate bound of the pairwise-error probability for ST coded systems over multipath and time-dispersive fading channels. It is shown that the presence of multipath does not reduce the diversity gain provided by the original design criteria, which is adopted to construct specific ST codes in quasi-static flat fading, but the coding gain diminishes due to the effect of multipath fading.

关键词： delay spread intersymbol interference multipath fading space-time coding wireless communications

来源：评论

学校读者我要写书评

暂无评论

Alternative Codes and Phase Rotation Extensions for Alternating space-time coding-Based Physical Layer Security

IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY

引用

IEEE OPEN JOURNAL OF THE COMMUNICATIONS SOCIETY 2021年 2卷 1123-1143页

作者： Cribbs, Michael R. Romero, Ric A. Ha, Tri T. Naval Postgrad Sch Dept Elect & Comp Engn Monterey CA 93943 USA

In this article, several extensions to an alternating space-time (ST) code (STC) physical layer security (PLS) scheme from the literature are proposed. These contributions include alternative orthogonal STCs as well as non-orthogonal and spatially-multiplexed (SM) STCs for improved bandwidth efficiency. Phase rotation (PR) algorithms are provided to build very large sets of unique alternative STCs for use with this scheme. Decoding methods are discussed for alternating non-orthogonal and SM STCs. Monte Carlo simulations are provided to compare bit error rate (BER) performance between different decoding methods. Secrecy system nomenclature is adapted to the alternative STCs and proposed algorithms. Information-theoretic security analysis including message and key equivocation is provided along with expected eavesdropper BER based on an assumed attack methodology. A comparison of security offered by the alternating STC PLS scheme with and without incorporation of proposed PR algorithms is performed. Substantially greater exhaustive key search attack complexity is achieved by using the PR algorithms proposed in this article.

关键词： Buildings Security Three-dimensional displays Bit error rate Signal processing algorithms Physical layer security Decoding Key equivocation key residue class message equivocation phase rotation physical layer security space-time 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：