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Telecommunications Forum Telfor

作者： C. Voicu E. S. Lohan S. Halunga Telecommunication Department Electronics Telecommunications & Information Technology Faculty University "Politehnica" of Bucharest Department of Electronics and Communications Engineering Tampere University of Technology

ISBN: (纸本)9781479914180

This paper presents the results obtained by a new multiuser detector based on the Projection Onto Convex Sets (POCS) deconvolution algorithm, in comparison with those obtained by the decorrelating detector, when the channel is affected by the flat Rayleigh fading and gray images are transmitted through the system. All the users transmit their information with the same power, but the spreading codes are correlated. We will investigate the fading effect on the received images and the impact of the cross-correlation of the spreading codes on the quality of the received images. In the end, several conclusions are highlighted, with respect to the level of performance achieved.

关键词： Decorrelating detector POCS algorithm Image transmission space-time block coding Universal image quality index Visual information fidelity index

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Statistical Performance Analysis for MIMO Beamforming and STBC when Co-Channel Interferers Use Arbitrary MIMO Modes

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IEEE TRANSACTIONS ON COMMUNICATIONS 2012年第10期60卷 2926-2937页

作者： Zhang, Lu Li, Yongzhao Cimini, Leonard J. Alcatel Lucent Shanghai Bell Co Ltd Shanghai Peoples R China Xidian Univ State Key Lab Integrated Serv Networks Xian Peoples R China Univ Delaware Newark DE 19716 USA

In a cellular-like system, the multiple-input multiple-output (MIMO) mode used by a base station (BS) can be adaptively varied among several candidate MIMO modes(1), including space-time block coding (STBC), open-loop spatial multiplexing (OLSM), closed-loop spatial multiplexing (CLSM), MIMO beamforming (MBF), and maximal ratio transmission (MRT). In practice, during any one given period of time, when the desired BS performs downlink transmission with a specific MIMO mode, each co-channel interfering BS will use a MIMO mode the same as or different from that used in the desired link and any two co-channel interfering BSs may use different MIMO modes, so that the interference scenario becomes quite complicated. In this paper, considering realistic propagation conditions including both path-loss and Rayleigh fading and considering the existence of unequal-power interferers, the statistical distributions of the post-processing signal-to-interference ratios (SIRs) for either MBF or STBC downlink transmissions are analyzed when co-channel interfering BSs employ arbitrary MIMO modes. In particular, closed-form expressions for the probability density function (PDF) of the interference terms in the post-processing SIRs are derived. Further, the statistical distributions of the post-processing SIRs are analyzed. Simulation results verify the validity of the theoretical analyses.

关键词： IMO MIMO beamforming space-time block coding co-channel interferers with mixed MIMO modes post-processing SIR statistical distribution. IMO MIMO beamforming space-time block coding co-channel interferers with mixed MIMO modes post-processing SIR statistical distribution. M

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

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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

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space-time Processing for X Channels Using Precoders

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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

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Very-large-scale integration hardware implementation of adaptive space-time coding/spatial multiplexing switching

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IET COMMUNICATIONS 2012年第10期6卷 1316-1325页

作者： Nurmi, W. Nooshabadi, S. Univ Turku Dept Informat Technol SF-20500 Turku Finland Michigan Technol Univ Dept Elect & Comp Engn Houghton MI 49931 USA

Multiple input multiple output (MIMO) techniques are widely employed in modern wireless systems. The most prominent approaches to MIMO communication are space-time coding (STC) and spatial multiplexing (SM). Less studied is a hybrid technique called adaptive MIMO switching (AMS), which may be employed by fixing the transmission rate and selecting between space-time block coding and SM transmission modes based on instantaneous channel conditions to achieve the most efficient link. This study presents a hardware implementations of a selector algorithm and a detector employing it. The detector is designed for a 2 x 2 MIMO system and was implemented on an Altera Cyclone II FPGA. In addition, two transmission protocols with decision feedback from the receiver to the transmitter via a low-rate feedback channel are introduced and the feasibility of switching for high-data-rate transmissions is discussed.

关键词： Communication switching automatic repeat request Protocols space division multiplexing telecommunication channels multiple input multiple output communication radio transmitters space-time codes Codes very-large-scale integration hardware implementation decision feedback low-rate feedback channel adaptive MIMO switching receiver field programmable gate arrays radio receivers MIMO system two transmission protocols spatial multiplexing switching space-time block coding protocols transmitter adaptive codes Altera Cyclone II FPGA adaptive space-time coding Radio links and equipment MIMO communication modern wireless systems

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A Reliable Group-Simulcasting Scheme for Distributed Antenna Systems

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2012年第1期11卷 236-245页

作者： Huang, Shengchun Li, Haoming Wu, Jiangxing Leung, Victor C. M. Natl Univ Def Technol Sch Elect Sci & Engn Changsha 410073 Hunan Peoples R China Univ British Columbia Dept Elect & Comp Engn Vancouver BC V6T 1Z4 Canada Natl Digital Switching Syst Engn & Technol Res Ct Zhengzhou Peoples R China

Simulcasting involves transmitting the same signal simultaneously over several antennas on the same carrier frequency. We derive the optimal grouping condition for simulcasting over a massively distributed antenna system (DAS) employing orthogonal space-time block coding (STBC), where the order of the STBC coding matrix n(o) is smaller than the number of remote antenna units (RAUs). While the optimum grouping minimizes the average bit error rate (BER) in the coverage area, we further propose two heuristic grouping rules and derive the corresponding stream-balanced grouping schemes in three DAS topologies, namely, linear, hexagonal and square lattice, to achieve low average BER across the area covered by the DAS. Simulation results for the different topologies confirm the superiority of the proposed grouping schemes compared with the other grouping methods. Also, when either n(o) or the RAU density increases, the average BER decreases.

关键词： Group-simulcasting space-time block coding distributed antenna system

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A CONVEX INNER APPROXIMATION TECHNIQUE FOR RANK-TWO BEAMFORMING IN MULTICASTING RELAY NETWORKS

A CONVEX INNER APPROXIMATION TECHNIQUE FOR RANK-TWO BEAMFORM...

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20th European Signal Processing Conference (EUSIPCO)

作者： Schad, Adrian Law, Ka L. Pesavento, Marius Tech Univ Darmstadt Commun Syst Grp D-64283 Darmstadt Germany

ISBN: (纸本)9781467310680

In this paper, we propose a novel scheme for single-group multicasting using a relay network. We assume a source that transmits messages via an amplify-and-forward relay network to multiple destinations. The goal is to minimize the maximum transmitted power of the relays under constraints on the signal-to-noise ratios at the destinations. To increase the degrees of freedoms in the system, the relays process two source signals jointly, using two different relay beamforming weight vectors. The Alamouti space-time block code is transmitted over two beams. Simulation results demonstrate the performance of the proposed scheme combined with a proposed sequential convex programming algorithm compared to methods of the literature and to the theoretical lower bound.

关键词： Amplify-and-forward convex optimization relay networks distributed beamforming multicasting space-time block coding

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Performance bounds of space-time block coding in Rician and log-normal fading channels

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IET COMMUNICATIONS 2007年第1期1卷 86-91页

作者： Papadopoulos, G. D. Karagiannidis, G. K. Pavlidou, F. N. Aristotle Univ Thessaloniki Dept Elect & Comp Engn Div Telecommun GR-54124 Thessaloniki Greece

Analytical expressions concerning the capacity and bit error rate (BER) of multiple-input multiple-output systems with space-time block coding (STBC) are derived. Two fading environments are examined, log-normal and Rician channels. A tight closed-form upper bound is presented for the BER of systems operating in log-normal fading environments in addition to an upper bound for the capacity of this type of systems. The latter bound applies to systems that operate under Rician fading as well. The analytical results were validated against ample numerical simulations for three STBC schemes and three phase-shift-keying modulations. The proposed bounds proved to. be a tractable way to evaluate the system performance when no closed-form expression for the probability density function or the moment generating function is known.

关键词： block codes closed-form upper bound Rician channels capacity probability density function MIMO communication BER phase shift keying log-normal fading channels log normal distribution channel capacity space-time block coding STBC scheme Rician channels error statistics channel coding phase-shift-keying modulations bit error rate moment generating function multiple-input multiple-output systems space-time codes

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An analytical approach to space-time block coding with decision feedhack channel estimation

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2007年第3期56卷 1442-1447页

作者： Garg, Parul Mallik, Ranjan K. Gupta, Hari M. Netaji Subhas Inst Technol Div Elect & Commun Engn New Delhi 110075 India Indian Inst Technol Dept Elect Engn New Delhi 110016 India

We consider a space-time block coded system having L time slots and using decision feedback channel estimation with a finite window size. The channel matrix estimate is updated every L time slots by: 1) a least-squares (LS) estimate and 2) a minimum mean-square error (MMSE) estimate. Using a Markov model of the decision process, we analyze the decoding error probability (DEP) of this scheme in Rayleigh fading. The transition probability matrix is obtained. by simulation of the decision process for a system using the Alamouti code. From this matrix, the DEP can be computed for any time shift. We find from computations that the DEP increases with increase in the time shift but tends to saturate with time to a steady-state value. It is also observed that both the state and the transition probabilities tend to saturate with the increase in average signal-to-noise ratio per diversity branch.

关键词： decision feedback channel estimation (DFCE) decoding error probability (DEP) Markov model Rayleigh fading space-time block coding

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Full-rate and low-complexity space-time block coding concatenated with channel codes

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INTERNATIONAL JOURNAL OF INFORMATION TECHNOLOGY & DECISION MAKING 2007年第1期6卷 5-14页

作者： Yu, Xiangbin Bi, Guangguo Nanjing Univ Aeronaut & Astronaut Coll Informat Sci & Technol Nanjing 210016 Peoples R China Southeast Univ Natl Mobile Commun Res LAb Nanjing 210096 Peoples R China

space-time block (STB) coding has been an effective transmit diversity technique for combating fading recently. In this paper, a full-rate and low-complexity STB coding scheme with complex orthogonal design for multiple antennas is proposed, and turbo code is employed as channel coding to improve the proposed code scheme performance further. Compared with full-diversity multiple antennas STB coding schemes, the proposed scheme can implement full data rate, partial diversity and a smaller complexity, and has more spatial redundancy information. Moreover, using the proposed scheme can form efficient spatial interleaving, thus performance loss due to partial diversity is effectively compensated by the concatenation of turbo coding. Simulation results show that on the condition of the same system throughput and concatenation of turbo code, the proposed scheme has lower bit error rate (BER) than those low-rate and full-diversity multiple antennas STB coding schemes.

关键词： space-time block coding full rate low complexity turbo code transmit diversity multiple antennas

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