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Noncoherent Amplitude/Phase Modulated Transmission Schemes for Rayleigh Block Fading Channels

IEEE TRANSACTIONS ON COMMUNICATIONS 2013年第1期61卷 217-227页

作者： Chen, Yen-Ming Ueng, Yeong-Luh Natl Tsing Hua Univ Dept Elect Engn Hsinchu 30013 Taiwan Natl Tsing Hua Univ Inst Commun Engn Hsinchu 30013 Taiwan

In this paper, we investigate noncoherent transmission schemes using amplitude/phase modulation. For uncoded transmission schemes, we derive the pairwise error probability ( PEP) and its high-SNR approximation for signal vectors with unequal power values using a noncoherent maximum-likelihood detector under Rayleigh block fading channels. For coded transmission schemes, we consider differential amplitude/phase modulated signals and introduce a codeword-interleaving strategy to improve the error performance. The design criteria for the signal labelling and bit interleaving are also derived via the high-SNR approximation of the PEP. At the receiver, we devise an iterative channel amplitude estimator to enhance the detection reliability. With the help of a specially-designed iterative receiving algorithm, the designed noncoherent coded scheme can provide a significant improvement, either in the error-floor or the waterfall region.

关键词： iterative detection and decoding noncoherent detection noncoherent distance amplitude/phase modulation

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The impact of channel estimation errors and co-antenna interference on the performance of a coded MIMO system

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EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2005年第11期2005卷 1680-1697页

作者： Mysore, N Bajcsy, J McGill Univ Dept Elect & Comp Engn Montreal PQ H3A 2A7 Canada

This paper considers the problem of uplink transmission over multiple-input multiple-output (MIMO) channels affected by slow frequency-nonselective uncorrelated and correlated Rayleigh fading. We consider the case when channel state information, corrupted by estimation errors, is available at the receiver only. In this setting, we generalize the derivation of our previously proposed linear-complexity MIMO signal detector and derive closed-form expressions for the distribution of its soft outputs and the approximate symbol error probability. Based on this soft decision detector, we consider a turbo-coded MIMO uplink architecture with iterative processing, which enables performance within 1.6 to 2.8 dB of the ergodic capacity limit and outperforms the T-BLAST (turbo-Bell Laboratories layered space-time) system by about 10 dB at bit error rates of 10(-5). The presented results illustrate that this linear-complexity MIMO signal detector is highly robust to channel estimation errors.

关键词： coded MIMO systems channel estimation errors MIMO signal detection iterative detection and decoding

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On the Information Rate and Repeat-Accumulate Code Design for Phase Noise Channels

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IEEE TRANSACTIONS ON COMMUNICATIONS 2011年第12期59卷 3223-3228页

作者： Barbieri, Alan Colavolpe, Giulio Univ Parma Dipartimento Ingn Informaz I-43100 Parma Italy

We investigate the information rate of channels affected by phase noise, aiming at predicting the ultimate performance limits in this scenario. Moreover, a closed-form upper bound is also derived for phase shift keying (PSK) modulations. Finally, we consider the design of nonsystematic irregular repeat-accumulate (RA) codes for this channel trying to give new insights on the codes to be employed for such an application.

关键词： Differential encoding iterative detection and decoding detection and decoding in the presence of phase noise

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A Maximum Logarithmic Maximum a Posteriori Probability Based Soft-Input Soft-Output Detector for the Coded Spatial Modulation Systems

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS 2022年第9期69卷 3816-3828页

作者： Liu, Tsung-Hsien Jiang, Ting-Xu Chung, Ching-Che Chu, Yuan-Sun Natl Chung Cheng Univ Dept Commun Engn Chiayi 621301 Taiwan Natl Chung Cheng Univ Adv Inst Mfg High Tech Innovat AIM HI Chiayi 621301 Taiwan Natl Chung Cheng Univ Dept Elect Engn Chiayi 621301 Taiwan Natl Chung Cheng Univ Dept Comp Sci & Informat Engn Chiayi 62102 Taiwan

Soft-input soft-output (SISO) detector for the iterative detection and decoding of coded spatial modulation (SM) signals needs to compute the extrinsic bit log-likelihood ratio (LLR) associated with each detected bit. The maximum logarithmic maximum a posteriori (max-log-MAP) detector is known to perform closely to the optimal logarithmic maximum a posteriori (log-MAP) detector with much lower computational complexity. In this paper, we first apply several mathematical tricks to derive a new and low-complexity algorithm for the max-log-MAP detector. The proposed algorithm features a new tree pruning technique to visit few lattice points and a smart list administration technique to retain a max-log-MAP detector. By following the proposed algorithm, we then design a hardware architecture for SISO detection of coded SM signals over the scenario of 64-QAM symbols, 8 transmit antennas, and 4 receive antennas. Under the TSMC 40 nm CMOS technology, the VLSI implementation results reveal that our architecture requires 46.4K gates and leads to detection throughput 450 Mbps, while operating at clock frequency 400 MHz and consuming power 46 mW. Being the first hardware architecture for SISO detection of coded SM signals, our proposed low-cost max-log-MAP detector is very attractive.

关键词： Detectors Symbols Computer architecture MIMO communication Indexes Modulation iterative decoding Spatial modulation maximum a posteriori detection log-likelihood ratio maximum logarithm approximation iterative detection and decoding soft-input soft-output detection

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Frequency Packing and Multiuser detection for CPMs: How to Improve the Spectral Efficiency of DVB-RCS2 Systems

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IEEE WIRELESS COMMUNICATIONS LETTERS 2013年第1期2卷 74-77页

作者： Piemontese, Amina Graell i Amat, Alexandre Colavolpe, Giulio CNIT Viale GP Usberti 181A I-43124 Parma Italy Univ Parma Dipartimento Ingn Informaz Viale GP Usberti 181A I-43124 Parma Italy Chalmers Dept Signals & Syst S-41296 Gothenburg Sweden

We consider a frequency division multiplexed system where each user adopts a continuous phase modulation (CPM) and multiuser detection is employed at the receiver side. The spectral efficiency (SE) is used as a performance measure to compare, from an information-theoretic point of view, different modulation formats. More precisely, we consider the new CPM formats recently included in the DVB-RCS2 standard. We describe a framework for computing the information rate (IR) and the SE of such systems, and use it for optimizing the channel spacing between adjacent users and the CPM phase response. Our analysis reveals that modulation formats adopted in the DVB-RCS2 standard are suboptimal in terms of SE, while if we allow multiuser detection excellent performance can be achieved by using simple binary formats and highly frequency packed signals. Furthermore, we consider practical schemes, where CPMs are serially concatenated with an outer code, and a low-complexity multiuser receiver is employed, showing that the theoretical limits predicted by the IR analysis can be approached.

关键词： Continuous phase modulations iterative detection and decoding multiuser detection information rate spectral efficiency

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Robust detection of Binary CPMs With Unknown Modulation Index

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IEEE COMMUNICATIONS LETTERS 2015年第3期19卷 339-342页

作者： Messai, Malek Colavolpe, Giulio Amis, Karine Guilloud, Frederic Telecom Bretagne Inst Telecom Signal & Commun Dept F-29200 Brest France Univ Parma Dipartimento Ingn Informaz I-43124 Parma Italy

We consider soft-output detection of a binary continuous phase modulation (CPM) generated through a low-cost transmitter, thus characterized by a significant modulation index uncertainty, and sent over a channel affected by phase noise. The proposed detector is designed by adopting a simplified representation of a binary CPM signal with the principal component of its Laurent decomposition and is obtained by using the framework based on factor graphs and the sum-product algorithm. It does not require an explicit estimation of the modulation index nor of the channel phase and is very robust to large uncertainties of the nominal value of the modulation index. Being soft-output in nature, this detector can be employed for iterative detection/decoding of practical coded schemes based on a serial concatenation, possibly through a pseudo-random interleaver, of an outer encoder and a CPM modulation format.

关键词： Continuous phase modulation modulation index mismatch phase noise factor graph sum product iterative detection and decoding

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Efficient Soft-Input Soft-Output MIMO Chase Detectors for Arbitrary Number of Streams

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IEEE SIGNAL PROCESSING LETTERS 2015年第8期22卷 1084-1088页

作者： Gomaa, Ahmad Jalloul, Louay M-A. Cairo Univ Cairo Egypt Qualcomm Inc San Jose CA 95110 USA

We present novel soft-input soft-output (SISO) multiple-input multiple-output (MIMO) detectors based on the Chase detection principle [1] in the context of iterative detection and decoding (IDD). The proposed detector complexity is linear in the signal modulation constellation size and the number of spatial streams. Two variants of the SISO detector are developed, referred to as SISO block decision-feedback Chase detector (B-Chase) and SISO linear Chase detector (L-Chase). An efficient method is presented that uses the decoder output to modulate the signal constellation decision boundaries inside the detector leading to the SISO detector architecture. The performance of these detectors significantly improves with just a few number of IDD iterations. The effect of transmit and receive antenna correlation is simulated. For the high-correlation case, the superiority of SISO B-Chase over the SISO L-Chase is demonstrated.

关键词： Chase detection B-Chase detector iterative detection and decoding L-Chase detector MIMO-OFDM soft-input soft-output MIMO detector turbo equalization

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Multiuser decoding Scheme for K-user Fading Multiple-Access Channel Based on Physical-Layer Network Coding

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IEEE COMMUNICATIONS LETTERS 2016年第5期20卷 1046-1049页

作者： Yang, Lei Yang, Tao Xie, Yixuan Yuan, Jinhong An, Jianping Univ New S Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia Univ Technol Sydney Global Big Data Technol Ctr 81 Broadway Sydney NSW 2007 Australia Univ New S Wales Dept Engn Kensington NSW 2052 Australia Beijing Inst Technol Sch Informat & Elect Beijing 100081 Peoples R China

We propose a new practical multiuser decoding scheme based on physical-layer network coding (PNC) for a K-user fading multiple-access channel. In the scheme, the users encode their messages with a same practical channel code, and the coded and modulated signals are transmitted simultaneously. The receiver first reconstructs K linear functions of the K users' messages based on PNC. Then all messages are recovered by solving the K linear equations. Compared to the well-known iterative detection and decoding schemes, we show by numerical results that the proposed scheme achieves near interference-free bound performance without utilizing receiver iterations.

关键词： Multiple-access channel multiuser decoding physical-layer network coding iterative detection and decoding

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iterative Channel Estimation Using Virtual Pilot Signals for MIMO-OFDM Systems

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2015年第12期63卷 3032-3045页

作者： Park, Sunho Shim, Byonghyo Choi, Jun Won Korea Univ Sch Informat & Commun Seoul South Korea Seoul Natl Univ Dept Elect & Comp Engn Seoul 136701 South Korea Seoul Natl Univ Inst New Media & Commun Seoul 136701 South Korea Seoul Natl Univ Sch Elect & Comp Engn Seoul 136701 South Korea Hanyang Univ Dept Elect Engn Seoul 133791 South Korea

The number of transmit and receive antennas in multi-input multi-output (MIMO) systems is increasing rapidly to enhance the throughput and reliability of next-generation wireless systems. Benefits of large size MIMO systems, however, can be realized only when the quality of estimated channels is ensured at the transmitter and receiver side alike. In this paper, we introduce a new decision-directed channel estimation technique dealing with pilot shortage in the MIMO-OFDM systems. The proposed channel estimator uses soft symbol decisions obtained by iterative detection and decoding (IDD) scheme to enhance the quality of channel estimate. Using the soft information from the decoders, the proposed channel estimator selects reliable data tones, subtracts interstream interferences, and performs re-estimation of the channels. We analyze the optimal data tone selection criterion, which accounts for the reliability of symbol decisions and correlation of channels between the data tones and pilot tones. From numerical simulations, we show that the proposed channel estimator achieves considerable improvement in system performance over the conventional channel estimators in realistic MIMO-OFDM scenarios.

关键词： Channel estimation decision directed channel estimation iterative detection and decoding joint channel estimation and detection multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM)

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Discrete MMSE Precoding for Multiuser MIMO Systems With PSK Modulation

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2022年第10期21卷 8817-8831页

作者： Lopes, Erico S. P. Landau, Lukas T. N. Pontifical Catholic Univ Rio de Janeiro Ctr Studies Telecommun BR-22453900 Rio De Janeiro Brazil

We propose an optimal MMSE precoding technique using quantized signals with constant envelope. Unlike the existing MMSE design that relies on 1-bit resolution, the proposed approach employs uniform phase quantization and the bounding step in the branch-and-bound method is different in terms of considering the most restrictive relaxation of the nonconvex problem, which is then utilized for a suboptimal design also. We also propose robust MMSE designs where we exploit second order statistics of a channel state information mismatch. Moreover, unlike prior studies, we propose three different soft detection methods and an iterative detection and decoding scheme that allow the utilization of channel coding in conjunction with low-resolution precoding. Besides an exact approach for computing the extrinsic information, we propose two approximations with reduced computational complexity. Numerical simulations show that utilizing the MMSE criterion instead of the established maximum-minimum distance to the decision threshold yields a lower bit-error-rate in many scenarios. Furthermore, when using the MMSE criterion, a smaller number of bound evaluations in the branch-and-bound method is required for low and medium SNR. Finally, results based on an LDPC block code indicate that the proposed receive processing schemes yield a lower bit-error-rate compared to the conventional design.

关键词： Precoding Quantization (signal) Wireless communication Signal processing algorithms Modulation MIMO communication iterative decoding Precoding low-resolution quantization phase quantization MIMO systems branch-and-bound methods MMSE constant envelope log-likelihood-ratios soft detection iterative detection and decoding

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