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An integrated analysis for MC-CDMA system with synchronization errors over fading channels

JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS 2006年第7期29卷 1185-1193页

作者： Chang, Chung-Liang Huang, Ping S. Tu, Te-Ming Natl Def Univ Chung Cheng Inst Technol Dept Elect Engn Tao Yuan 335 Taiwan

Synchronization errors and fading channels are individually considered in many previous studies. This study derives the average bit error rate (BER) of the uplink and downlink MC-CDMA systems using equal gain combining (EGC) with synchronization errors over the fading channels. The obtained average BER of the uplink and downlink MC-CDMA systems simultaneously considers most of the synchronization errors and the parameters of the fading channel. Since it is difficult to acquire the closed-form of average BER, the Chernoff bound is adopted to derive the upper bound of the average BER instead. Computer simulation results show that the performance of the uplink and downlink MC-CDMA systems are degraded by the fading channel and synchronization errors such as frequency offset, carrier phase jitter and timing jitter. This fully corresponds to theoretical derivations. Also, by comparing the uplink to the downlink systems, we conclude that the average BER of the downlink MC-CDMA system degrades faster due to the increasing value of synchronization errors.

关键词： synchronization errors multicarrier code-division multiple access fading channels equal gain combining (EGC)

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Spectral Sidelobe Decaying Property of Walsh-Hadamard code in MC-CDMA Systems

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2011年第10期10卷 3151-3157页

作者： Lin, Chia-Ching Chen, Wei-Chang Chung, Char-Dir Natl Taiwan Univ Grad Inst Commun Engn Taipei 10617 Taiwan Natl Taiwan Univ Dept Elect Engn Taipei 10617 Taiwan

In this letter, a spectral sidelobe-decaying property of the Walsh-Hadamard code employed in multicarrier codedivision multiple access (MC-CDMA) systems is exploited. It is shown that the sidelobe-decaying characteris... 详细信息

关键词： multicarrier code-division multiple access spectral sidelobe Walsh-Hadamard code orthogonal frequency-division multiplexing

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Equivalent Time-Domain Representation and Uplink Channel Estimator for multicarrier CDMA Systems

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Journal of Systems Engineering and Electronics 2003年第3期14卷 1-7页

作者：吴晓军殷勤业曾明 School of Electronics and Information Engineering Xi' an Jiaotong University Xi' an 710049 P. R. China

Many blind channel estimation methods have been proposed for direct sequence (DS) code-division multiple access (CDMA) systems, so we can certainly use them to estimate the finite impulse response (FIR) channel for the multi-carrier (MC-) CDMA system. In this paper, the MC-CDMA system is interpreted as an equivalent time-domain DS-CD-MA system with specific spreading codes. Then, an equivalently time-domain blind channel estimator is derived for the uplink MC-CDMA, which is based on second-order statistics of the received data. By exploiting singular value decomposition (SVD) and the finite alphabet property of transmitted symbols, the time-domain channel impulse response (CIR) for the uplink MC-CDMA can be accurately identified. Computer simulations illustrate both the validity and the overall performance of the proposed estimator.

关键词： multicarrier code-division multiple access Channel impulse response multiple access interference Intersym-bol interference Cyclic prefix Blind channel estimation Multiuser detection.

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Iterative semiblind multiuser receivers for a space-time block-coded MC-CDMA uplink system

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2004年第3期53卷 601-610页

作者： Kafle, PL Sesay, AB Univ Calgary Dept Elect & Comp Engn Calgary AB T2N 1N4 Canada

Iterative multiuser detection and space-time coding are two promising techniques to improve the capacity and performance of coded multiuser systems in wireless channels. In this paper, we present iterative multiuser detection schemes for a space-time block-coded multicarrier code-division multiple-access system with multiple transmit and receive antennas. We consider a more general case of an uplink system in the presence of both intra- and intercell interferences. We propose two types of iterative semiblind space-time receivers for such an uplink environment. The first is based on the minimum mean-square error criterion and the second is a hybrid scheme based on a combination of parallel interference cancellation and linear multiuser detection. These iterative receivers are derived, using a subspace approach, which utilizes known users' information for the computation of log-likelihood ratios (LLRs) while blindly suppressing the unknown interference. The LLRs are refined successively during the iterative process by using the extrinsic information available through decoding of all known users. A turbo code is used for channel coding. Simulation results in a frequency-selective Rayleigh-fading environment are presented to verify the performance of the proposed schemes.

关键词： multicarrier code-division multiple access (CDMA) semiblind multiuser detection space-time codes turbo processing

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Spectral Efficiency Comparison of Asynchronous MC-CDMA, MC DS-CDMA and MT-CDMA with Carrier Frequency Offset

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ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2019年第3期44卷 1833-1841页

作者： Ahmed, Junaid COMSATS Inst Informat Technol Dept Elect Engn Islamabad 45550 Pakistan

multicarrier code-division multiple access (MC-CDMA), multicarrier direct-sequence CDMA (MC DS-CDMA) and multitone CDMA (MT-CDMA) are three flavors of spread spectrum multicarrier communications. multiple access interference, inter-carrier interference, self-interference and noise are the major factors that deteriorate their spectral efficiency. A novel joint analysis of spectral efficiency is presented for asynchronous MC-CDMA, MC DS-CDMA and MT-CDMA in a frequency-selective Rayleigh fading environment. This allows us to compare performance of the three schemes in indoor and outdoor environments in the presence of interferers, carrier frequency offset, multipath fading and noise.

关键词： multicarrier code-division multiple access Spread spectrum communication OFDM Rayleigh channels

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Performance analysis of multiuser detectors for MC-CDMA in the presence of frequency offset

Performance analysis of multiuser detectors for MC-CDMA in t...

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IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Mashury Curtin Univ Technol Perth WA 6845 Australia

ISBN: (纸本)0780376633

A performance analysis of multiuser detectors for MC-CDMA over a fading channel in the presence of carrier frequency offset is presented in this paper. A theoretical analysis of the bit error probability of the detectors is derived. The theoretical analysis shows a close agreement to simulation results for a low value of the frequency offset and a high number of subcarriers. Based on the performance evaluation, multiuser detectors can tolerate only a small amount of frequency offset.

关键词： multiuser detection code division multiple access fading channels error statistics mobile radio frequency estimation performance analysis multiuser detectors multicarrier code-division multiple access MC-CDMA fading channel carrier frequency offset bit error probability subcarriers

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Transmit/receive beamformer design and power control in MIMO MC-CDMA systems

Transmit/receive beamformer design and power control in MIMO...

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IEEE International Symposium on Circuits and Systems

作者： Chan, S. C. Zhao, S. H. Univ Hong Kong Dept Elect & Elect Engn Pokfulam Rd Hong Kong Peoples R China

ISBN: (纸本)9780780393899

In this paper, a joint transmitter and receiver beamformers design algorithm for downlink multiple input multiple output multicarrier code-division multiple access (MIMO MC-CDMA) system is proposed. The algorithm is iterative in nature where the transmitter beamformers and the receiver beamformers are determined alternately. The transmitter beamforming problem with a given receiver beamformer is formulated as a convex programming problem, which can be solved optimally using second order cone programming (SOCP), while the receiver beamforming problem is formulated as a constrained optimization problem with an analytical solution. The convergence of the algorithm is analyzed and the performance of the proposed algorithm is evaluated by computing simulation.

关键词： MIMO systems code division multiple access power control transceivers MIMO convex programming problem iterative algorithm multicarrier code-division multiple access receiver beamformers second order cone programming transmit/receive beamfor

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Equivalent Time-Domain Representation and Uplink Channel Estimator for multicarrier CDMA Systems

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Chinese Journal of Systems Engineering and Electronics 2003年第3期000卷

Many blind channel estimation methods have been proposed for direct sequence (DS) code-division multiple access (CDMA) systems, so we can certainly use them to estimate the finite impulse response (FIR) channel for the multicarrier (MC-) CDMA system. In this paper, the MC-CDMA system is interpreted as an equivalent time-domain DS-CDMA system with specific spreading codes. Then, an equivalently time-domain blind channel estimator is derived for the uplink MC-CDMA, which is based on second-order statistics of the received data. By exploiting singular value decomposition (SVD) and the finite alphabet property of transmitted symbols, the time-domain channel impulse response (CIR) for the uplink MC-CDMA can be accurately identified. Computer simulations illustrate both the validity and the overall performance of the proposed estimator.

关键词： multicarrier code-division multiple access Channel impulse response multiple access interference Intersymbol interference Cyclic prefix Blind channel estimation Multiuser detection

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