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Towards maximum achievable diversity in space, time, and frequency: Performance analysis and code design

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2005年第4期4卷 1847-1857页

作者： Su, WF Safar, Z Liu, KJR SUNY Buffalo Dept Elect Engn Buffalo NY 14260 USA Nokia Danmark AS Technol Platforms Modern Syst Design Copenhagen Denmark Univ Maryland Dept Elect & Comp Engn College Pk MD 20742 USA Univ Maryland Inst Syst Res College Pk MD 20742 USA

Multiple input multiple output (MIMO) communication systems with orthogonal frequency division multiplexing (OFDM) modulation have a great potential to play an important role in the design of the next-generation broadband wireless communication systems. In this paper, we address the problem of performance analysis and code design for MIMO-OFDM systems when coding is applied over both spatial, temporal, and frequency domains. First, we provide an analytical framework for the performance analysis of MIMO-OFDM systems assuming arbitrary power delay profiles. Our general framework incorporates the space-time and space-frequency (SF) coding approaches as special cases. We also determine the maximum achievable diversity order, which is found to be the product of the number of transmit and receive antennas, the number of,delay paths,. and the rank of the temporal correlation matrix. Then, we propose two code design methods that are guaranteed to achieve the maximum diversity order. The first method is a repetition coding approach using full-diversity SF codes, and the second method is a block coding approach that can guarantee both full symbol rate and full diversity. Simulation results are also presented to support the theoretical analysis.

关键词： broadband wireless communications maximum achievable diversity MIMO-OFDM systems multiple antennas space-frequency coding space-time-frequency coding

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space-frequency Codes Based on the space-Time Codes With Very Low Complexity for the Decoder

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2013年第9期62卷 4678-4684页

作者： Shahabinejad, Mostafa Hosseini, Fatemeh G. Talebi, Siamak Shahid Bahonar Univ Kerman Dept Elect Engn Kerman Iran Sharif Univ Technol Adv Commun Res Inst Tehran Iran

In this paper, we introduce a family of full-diversity space-frequency codes (SFCs) for the multi-input-multi-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems. The most important feature of the proposed SFCs is that they can be swiftly decoded. More precisely, the decoding complexity on the order of O (M) or O(M-2) can be attained for the proposed full-diversity SFCs, where M is the constellation size. Simulation results have also verified that the proposed SFCs display outstanding performance in comparison with the latest SFC model published in the literature.

关键词： Fading channels frequency-selective channels multi-input-multi-output orthogonal frequency-division multiplexing (MIMO-OFDM)systems space-frequency coding wireless communication

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Blind channel estimation in MIMO-OFDM systems using semi-definite relaxation

Blind channel estimation in MIMO-OFDM systems using semi-def...

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33rd IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Sarmadi, Nima Gershman, Alex B. Shahbazpanahi, Shahram Tech Univ Darmstadt Commun Syst Grp D-64283 Darmstadt Germany Inst Technol Univ Ontario Fac Engn & Appl Sci London ON L1H7K4 Canada

ISBN: (纸本)9781424414833

A new blind channel estimation technique for multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems is proposed. It estimates the channel parameters in the time domain jointly for all subcarriers instead of doing this in the frequency domain independently for each subcarrier. This results in a substantially improved parsimony of the channel parameterization along with the ability to use coherent processing across the subcarriers. It is shown that using semi-definite relaxation (SDR), our channel estimation problem can be transferred to a convex form and then solved efficiently using modem convex optimization tools.

关键词： blind channel estimation space-frequency coding MIMO-OFDM systems semi-definite relaxation

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Full-Diversity space-frequency Trellis Codes Designing Method

Full-Diversity Space-Frequency Trellis Codes Designing Metho...

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13th International Symposium on Communications and Information Technologies (ISCIT) - Communication and Information Technology for New Life Style Beyond the Cloud

作者： Woradit, Kampol Srinakharinwirot Univ Dept Elect Engn Fac Engn Nakhonnayok Thailand

ISBN: (纸本)9781467355803;9781467355780

This paper introduces a method to design spacefrequency trellis codes for a system that combines space-time coding with orthogonal frequency division multiplexing (OFDM) to realize broad-band wireless communications. It has been pointed out in the literature that the frequency-selective fading, which usually occurs in such combined system, turns out to produce a beneficial effect on the error rate performance by providing the frequency diversity in addition to the spatial diversity. This enables space-frequency codes to exploit greater diversity than the space-time codes. However, exhaustive search for space-frequency trellis codes is impractical. The only existing heuristic design method has a drawback in the spectral efficiency, and in turn degrades the coding gain (energy efficiency,) which is also the primary purpose of space-frequency coding. We propose a practical method to design the space-frequency codes that exploit full diversity while maximizes the coding gain at a desired spectral efficiency. The simulation results show the superior error rate performance of the codes designed by the proposed method.

关键词： space-time signal processing space-frequency coding coded MIMO-OFDM energy-efficient communications

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Collision avoidance in space-frequency coded FH-OFDMA

Collision avoidance in space-frequency coded FH-OFDMA

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IEEE International Conference on Communications (ICC 2004)

作者： Kurt, T Deliç, H Univ Ottawa Sch Informat Technol & Engn Commun & Signal Proc Lab Ottawa ON K1N 6N5 Canada

ISBN: (纸本)0780385330

A frequency hopping, space-frequency coded clustered orthogonal frequency-division multiple access (OFDMA) system is considered. It is shown analytically that SIT coding reduces the number of collisions in OFDMA with random subcarrier hopping. Expressions for the expected number of symbol loss in a cluster collision are derived. Bit error rate computations via simulations in a frequency-selective fading channel corroborate the theoretical findings.

关键词： frequency-hopping OFDMA clustered OFDM space-frequency coding

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Distributed space frequency Coded Cooperative Network With Asymmetric Fading Channels 2

Distributed Space Frequency Coded Cooperative Network With A...

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2nd International Conference on Computational Intelligence & Communication Technology (CICT)

作者： Honrao, Bhagyashri Nema, Shikha Warty, Chirag SNDT Womens Univ Usha Mittal Inst Technol Bombay 400054 Maharashtra India SNDT Womens Univ Usha Mittal Inst Technol Dept Elect & Commun Bombay Maharashtra India Intelligent Commun Lab Bombay Maharashtra India Quantspire Bombay Maharashtra India

ISBN: (纸本)9781509002108

The wireless communication system frequency diversity can be exploited with the help of space frequency coding. In order to gain maximum frequency diversity various environment criteria needs to be considered. This paper proposes a practical approach of Distributed space frequency coding [DSFC] for non-identically distributed [i. n. d] fading environment. As the geographical location of nodes is different, accordingly the signal over the link will also experience different fading. One link may experience Rayleigh fading and other link may experience rician fading. When all the nodes are in shadow region, then it obviously shows poor performance as there is no direct line of sight [NLOS]. On other hand, when all link experiences rician fading, then it shows better performance as there is direct line of sight [LOS]. In asymmetric fading, each link experiences different type of fading depending on the location of the receiving node. Two types of Asymmetric Fading scenarios are designed for DSFC with direct link and without direct link. Asymmetric type I is designed for relay nodes that are located in better area compared to destination node. Asymmetric type II is designed for destination node which is located in better area compared to relay nodes. All these symmetrical and Asymmetrical fading scenarios are performed for both Amplify and Forward [AAF] and Decode and Forward [DAF] relaying protocol. Different modulation effect on proposed DSFC is compared for both relaying protocol. For both relaying protocol, it is observed that Asymmetric Type I shows better performance than Asymmetric Type II and Rayleigh fading.

关键词： Amplify and Forward Decode-and-Forward Rician Fading Rayleigh fading space-frequency coding

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Channel tracking and decoding in space-frequency coded OFDM systems over dispersive channels

Channel tracking and decoding in space-frequency coded OFDM ...

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7th International Conference on Signal Processing

作者： Xue, YM Su, GC Beijing Inst Technol Dept Electron Eng Informat Sci Beijing 100081 Peoples R China

ISBN: (纸本)7121002159

This paper proposes a novel decoding scheme for OFDM with multi-antenna systems. which uses space-frequency Block coding (SFBC), over time-frequency selective channels. We employ Kalman filtering for MIMO channel matrix tracking in order to enable SFBC-OFDM decoding with diversity gains. Simulation results confirm that the proposed scheme exhibits robustness to time-frequency selectivity.

关键词： Kalman filtering dispersive channels space-frequency coding OFDM

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Noncoherent sequence detection of differential space-frequency modulation MIMO-OFDM

Noncoherent sequence detection of differential space-frequen...

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8th IEEE Workshop on Signal Processing Advances in Wireless Communications

作者： Wang, Xin Li, Ying Wei, Jibo Natl Univ Def Technol Changsha Peoples R China

ISBN: (纸本)9781424409549

In a multiple-antenna broadband system, differential space-frequency modulation (DSFM) MIMO-OFDM in conjunction with noncoherent detection, which avoids channel state information (CSI) estimation, is attractive for time- and frequency selective channels for its reduced complexity. However, a long power-delay profile (PDP), which we encounter frequently in broadband systems, will deteriorate the performance rapidly. In this paper, a noncoherent sequence detection of DSFM MIMO-OFDM is proposed, which exploits the correlation among subcarriers and utilizes the past several symbols to detect the current one and it can be used to alleviate the performance degradation introduced by long PDPs. We also present an analytical approximation of the symbol-error rate (SER) for DSFM, which enables quick and accurate performance evaluations. Simulation results confirm the efficacy of our approach and it is more flexible than the fixed window multiple-symbols detection under variable numbers of subcarriers.

关键词： MIMO-OFDM space-frequency coding noncoherent sequence detection

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System Performance of Distributed Transmit Diversity for OFDM-based 1xEV-DO Broadcast Networks

System Performance of Distributed Transmit Diversity for OFD...

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IEEE Wireless Communications and Networking Conference

作者： Yoon, Young C. Savas, Alpaslan Chen, Wanshi Ericsson Inc. USA San Diego CA 92121 5012 Wateridge Vista Drive United States Ericsson Inc. United States LGE Mobile Research United States

ISBN: (纸本)9781424402694

This paper considers the application of distributed transmit diversity (TD) to digital broadcast networks. Distributed TD allows spatial encoding across transmit sectors (cell-sites or satellites) each with a single antenna. We focus on Alamouti space-frequency (SF) codes in particular and consider terrestrial systems based on cellular type networks. System coverage results are presented for a 1xEV-DO broadcast network based on a comprehensive evaluation methodology developed in 3GPP2 for system modeling and orthogonal frequency division modulation (OFDM). The results show that distributed transmit diversity can deliver significant coverage gains. For example, given a bandwidth of 1.25 MHz, a data rate of 1.2 Mbps and a minimum bit-error rate (BER) requirement of 0.1%, the broadcast coverage increases from roughly 40% in the absence of distributed TD to 70% with the Alamouti linear combiner and to 82% with a zero-forcing (ZF) spatial equalizer.

关键词： space-time coding space-frequency coding Transmit diversity Broadcast networks OFDM Site Diversity Digital Video Broadcasting (DVB)

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A space-time coded multiantenna OFDM scheme over frequency-selective fading channels

A space-time coded multiantenna OFDM scheme over frequency-s...

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10th IEEE International Conference on Electronics, Circuits and Systems

作者： Chen, SP Yao, TR Huazhong Univ Sci & Technol Dept Elect & Informat Engn Wuhan 430074 Hubei Peoples R China

ISBN: (纸本)0780381637

We introduce a novel space-time coding scheme, called space-time cyclic-delay coding (STCDC), for multiple input multiple output orthogonal frequency-division multiplexing (MIMO-OFDM) systems over frequency-selective fading channels. The scheme exploits the redundancy introduced by channel coding. The transmitter antennas send the cyclically delayed copies of OFDM symbols, and the receiver uses the maximum likelihood estimation method to estimate the transmitted sequence. We show that STCDC-OFDM can achieve the maximum diversity, which is the product of the number of transmitter antennas (N-l), the number of receiver antennas (N-r) and the channel length (L), if the error control code has at least a free distance of NlL. Compared with the existing space-time coding and space-frequency coded MIMO-OFDM techniques, the proposed scheme has the advantages of being independent from the number of transmit antennas and having a lower implementation complexity. Keywords: Cyclic delay coding, OFDM, space-time coding, space-frequency coding.

关键词： cyclic delay coding OFDM space-time coding space-frequency coding

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