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Lattice reduction-based iterative receivers: using partial bit-wise MMSE filter with randomised sampling and MAP-aided integer perturbation

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IET COMMUNICATIONS 2016年第11期10卷 1394-1400页

作者： Bai, Lin Li, Tian Zhao, Lewen Choi, Jinho Beihang Univ Sch Elect & Informat Engn Beijing Peoples R China Supelec Gif Sur Yvette France Gwangju Inst Sci & Technol Sch Informat & Commun Gwangju South Korea

For iterative detection and decoding (IDD) in multiple-input multiple-output systems, the maximum a posteriori probability (MAP) detector would be ideal in terms of the performance. However, due to its high computational complexity, various suboptimal low-complexity approximate MAP detectors have been studied. In this study, a lattice reduction (LR)-based detector is considered for a near-optimal performance for IDD. The authors improve further the performance by employing a partial bit-wise minimum mean square error (MMSE) approach with randomised sampling, which has a lower complexity than that of the full bit-wise MMSE method. Moreover, the list of candidate vectors obtained by randomised sampling is extended using a MAP-aided integer perturbation algorithm for a better performance with low additional complexity. Through simulation results, it is shown that a near-optimal performance can be obtained which is better than that of the LR-based randomised successive interference cancellation and the full bit-wise MMSE methods.

关键词： MIMO communication radio receivers iterative decoding least mean squares methods filtering theory maximum likelihood decoding probability computational complexity vectors interference suppression radiofrequency interference lattice reduction-based iterative receiver partial bit-wise MMSE filter randomised sampling MAP-aided integer perturbation algorithm iterative detection and decoding IDD multiple-input multiple-output system maximum a posteriori probability detector MAP detector suboptimal low-computational complexity LR minimum mean square error approach vector randomised successive interference cancellation full bit-wise MMSE method

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IDMA vs. CDMA: Analysis and Comparison of Two Multiple Access Schemes

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2012年第1期11卷 78-87页

作者： Kusume, Katsutoshi Bauch, Gerhard Utschick, Wolfgang DOCOMO Euro Labs D-80687 Munich Germany Univ Bundeswehr Munchen D-85577 Neubiberg Germany Tech Univ Munich D-80290 Munich Germany

This article presents comprehensive comparisons of interleave division multiple access (IDMA) and direct sequence code division multiple access (DS-CDMA) in terms of performance and complexity assuming iterative multiuser detection. IDMA can be seen as a special case of DS-CDMA with spreading gain of one using very low rate code and user-specific interleavers for user separation. We focus on three suboptimum linear detectors: minimum mean square error (MMSE), rake (or matched filter), and soft-rake detectors from practical concerns. We analytically prove that the three detectors are equivalent for asynchronous users of IDMA on frequency flat channels for complex modulation alphabets. Such equivalence has been shown only for binary phase shift keying (BPSK) in the literature. The equivalence guarantees the MMSE solution for IDMA without computationally expensive matrix inversions or matrix-vector multiplications. This is generally not the case for DS-CDMA since DS-CDMA is sensitive to user asynchronism. We also discuss complexity aspects when the MMSE detector is used where we focus on essential differences in complexity between IDMA and DS-CDMA, instead of discussing particular complexity reduction techniques. Computer simulations are performed in various scenarios and the performance is analyzed by bit error rate simulations as well as by extrinsic information transfer (EXIT) charts. The analysis reveals the advantages of IDMA over DSCDMA in terms of performance and complexity under practical considerations, particularly in highly user loaded scenarios.

关键词： Interleave division multiple access (IDMA) direct sequence code division multiple access (DS-CDMA) multiuser detection iterative detection and decoding

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Improved Linear Soft-Input Soft-Output detection via Soft Feedback Successive Interference Cancellation

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IEEE TRANSACTIONS ON COMMUNICATIONS 2010年第3期58卷 986-996页

作者： Choi, Jun Won Singer, Andrew C. Lee, Jungwoo Cho, Nam Ik Univ Illinois Coordinated Sci Lab Urbana IL 61801 USA Seoul Natl Univ ECE Dept Seoul South Korea

We propose an improved minimum mean square error (MMSE) vertical Bell Labs layered space-time (V-BLAST) detection technique, called a soft input, soft output, and soft feedback (SIOF) V-BLAST detector, for turbo multi-input multi-output (Turbo-MIMO) systems. We derive a symbol estimator by minimizing the power of the interference plus noise, given a priori probabilities of undetected layer symbols and a posteriori probabilities for past detected layer symbols. For a low-complexity implementation, an approximate SIOF algorithm is presented, which allows for a time-invariant realization of the symbol ordering and an MMSE filtering process. Another implementation, referred to as the iterative SIOF algorithm is introduced, which decides on symbol detection order based on a posteriori symbol probabilities to improve the detection performance. Simulations performed on a space-time bit-interleaved coded modulation (STBICM) architecture over quasi-static MIMO fading channels demonstrate that the SIOF V-BLAST detector provides performance gains over previous Turbo-BLAST detectors, most notably when more transmit antennas are used.

关键词： V-BLAST turbo MIMO MMSE soft feedback SISO iterative detection and decoding

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AFDM-SCMA: A Promising Waveform for Massive Connectivity Over High Mobility Channels

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2024年第10期23卷 14421-14436页

作者： Luo, Qu Xiao, Pei Liu, Zilong Wan, Ziwei Thomos, Nikolaos Gao, Zhen He, Ziming Univ Surrey Innovat Ctr 5G 6G Guildford GU2 7XH Surrey England Univ Essex Sch Comp Sci & Elect Engn Colchester CO4 3SQ Essex England Beijing Inst Technol Sch Informat & Elect Beijing 100081 Peoples R China Beijing Inst Technol BIT Sch Informat & Elect Beijing 100081 Peoples R China Beijing Inst Technol BIT MIIT Key Lab Complex Field Intelligent Sensing Beijing 100081 Peoples R China BIT Zhuhai 519088 Peoples R China BIT Jinan Adv Technol Res Inst Jinan 250307 Peoples R China BIT Jiaxing Yangtze Delta Reg Acad Jiaxing 314019 Peoples R China Samsung Elect Samsung Cambridge Solut Ctr Syst LSI Cambridge CB4 0DS England

This paper studies the affine frequency division multiplexing (AFDM)-empowered sparse code multiple access (SCMA) system, referred to as AFDM-SCMA, for supporting massive connectivity in high-mobility environments. First, by placing the sparse codewords on the AFDM chirp subcarriers, the input-output (I/O) relation of AFDM-SCMA systems is presented. Next, we delve into the generalized receiver design, chirp rate selection, and error rate performance of the proposed AFDM-SCMA. The proposed AFDM-SCMA is shown to provide a general framework and subsume the existing OFDM-SCMA as a special case. Third, for efficient transceiver design, we further propose a class of sparse codebooks for simplifying the I/O relation, referred to as I/O relation-inspired codebook design in this paper. Building upon these codebooks, we propose a novel iterative detection and decoding scheme with linear minimum mean square error (LMMSE) estimator for both downlink and uplink channels based on orthogonal approximate message passing principles. Our numerical results demonstrate the superiority of the proposed AFDM-SCMA systems over OFDM-SCMA systems in terms of the error rate performance. We show that the proposed receiver can significantly enhance the error rate performance while reducing the detection complexity.

关键词： OFDM Receivers iterative decoding Complexity theory Chirp NOMA Wireless communication Sparse code multiple access (SCMA) affine frequency division multiplexing (AFDM) chirp subcarrier high-mobility channels codebook design orthogonal approximate message passing (OAMP) iterative detection and decoding

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RIePDMA and BP-IDD-IC detection

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EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 2017年第1期2017卷 1页

作者： Zeng, Jie Kong, Dan Liu, Bei Su, Xin Lv, Tiejun Beijing Univ Posts & Telecommun Beijing 100876 Peoples R China Tsinghua Univ Beijing 100084 Peoples R China Chongqing Univ Posts & Telecommun Chongqing 400065 Peoples R China

Pattern division multiple access (PDMA) is a non-orthogonal multiple access (NOMA) scheme which is proposed to meet the demand of massive connection in the future 5G communications. In this paper, we build a random interleaver (RI) enhanced PDMA (RIePDMA) system by bringing the random interleaver into a PDMA system to further improve the overload of PDMA. Furthermore, we analyze several integrated detection and decoding algorithms with interference cancellation (IC) and propose the iterative detection and decoding based on belief propagation and interference cancellation (BP-IDD-IC). Simulation results show that the proposed RIePDMA system can achieve better block error rate (BLER) performance without increasing the complexity of the receiver. Compared with several other integrated detection and decoding algorithms, the proposed BP-IDD-IC algorithm can get better BLER performance with an acceptable complexity.

关键词： Pattern division multiple access Random interleaver Belief propagation iterative detection and decoding

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Design of irregular repeat accumulate codes for OFDM systems with partial channel state information

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2005年第5期4卷 2491-2497页

作者： Sankar, H Narayanan, KR Texas A&M Univ Dept Elect Engn College Stn TX 77843 USA

Irregular repeat accumulate (IRA) codes perform very close to capacity on some memory-less channels with coherent detection. Further, they can be encoded and decoded in linear time. This paper considers the design of IRA codes for intersymbol interference (ISI) channels when only partial channel state information (CSI) is available at the receiver and orthogonal frequency-division multiplexing (OFDM) is used as the modulation format. The authors use a simple receiver structure that performs iterative channel estimation and decoding and use nonsystematic IRA codes that are optimized for this receiver. This combination is shown to perform within a few tenths of a decibel from the capacity of a receiver with perfect CSI and is also shown to be robust to change in the number of channel taps and Doppler.

关键词： channel capacity channel coding extrinsic information transfer (EXIT) charts fast Fourier transform (FFT) irregular repeat accumulate (IRA) codes iterative detection and decoding orthogonal frequency-division multiplexing (OFDM) partial channel state information Rayleigh fading channels

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Differential Active Self-Interference Cancellation for Asynchronous In-Band Full-Duplex GFSK

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IEICE TRANSACTIONS ON COMMUNICATIONS 2024年第8期E107B卷 552-563页

作者： Ibi, Shinsuke Takahashi, Takumi Iwai, Hisato Doshisha Univ Fac Sci & Engn Kyotanabe 6100394 Japan Osaka Univ Grad Sch Engn Suita 5650871 Japan

This paper proposes a novel differential active self- interference canceller (DASIC) algorithm for asynchronous in-band full- duplex (IBFD) Gaussian filtered frequency shift keying (GFSK), which is designed for wireless Internet of Things (IoT). In IBFD communications, where two terminals simultaneously transmit and receive signals in the same frequency band, there is an extremely strong self-interference (SI). The SI can be mitigated by an active SI canceller (ASIC), which subtracts an interference replica based on channel state information (CSI) from the received signal. The challenging problem is the realization of asynchronous IBFD for wireless IoT in indoor environments. In the asynchronous mode, pilot contamination is induced by the non-orthogonality between asynchronous pilot sequences. In addition, the transceiver suffers from analog front-end (AFE) impairments, such as phase noise. Due to these impairments, the SI cannot be canceled entirely at the receiver, resulting in residual interference. To address the above issue, the DASIC incorporates the principle of the differential codec, which enables to suppress SI without the CSI estimation of SI owing to the differential structure. Also, on the premise of using an error correction technique, iterative detection and decoding (IDD) is applied to improve the detection capability while exchanging the extrinsic log-likelihood ratio (LLR) between the maximum a-posteriori probability (MAP) detector and the channel decoder. Finally, the validity of using the DASIC algorithm is evaluated by computer simulations in terms of the packet error rate (PER). The results clearly demonstrate the possibility of realizing asynchronous IBFD.

关键词： pilot contamination GFSK active self-interference canceller differential encoder iterative detection and decoding analog front-end impairment

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Low-complexity approximate iterative LMMSE detection for large-scale MIMO systems

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DIGITAL SIGNAL PROCESSING 2017年 60卷 134-139页

作者： He, Xiaochen Guo, Qinghua Tong, Jun Xi, Jiangtao Yu, Yanguang Univ Wollongong Sch Elect Comp & Telecommun Engn Wollongong NSW 2522 Australia City Univ Hong Kong Kowloon Hong Kong Peoples R China

This paper deals with iterative detection for uplink large-scale MIMO systems. The well-known iterative linear minimum mean squared error (LMMSE) detector requires quadratic complexity (per symbol per iteration) with the number of antennas, which may be a concern in large-scale MIMO. In this work, we develop approximate iterative LMMSE detectors based on transformed system models where the transformation matrices are obtained through channel matrix decompositions. It is shown that, with quasi-linear complexity (per symbol per iteration), the proposed detectors can achieve almost the same performance as the conventional LMMSE detector. It is worth mentioning that the linear transformations are also useful to reduce the complexity of downlink precoding, so the relevant computational complexity can be shared by both uplink and downlink. (C) 2016 Elsevier Inc. All rights reserved.

关键词： Large-scale MIMO Linear minimum mean squared error (LMMSE) Singular value decomposition (SVD) Bi-diagonalization iterative detection and decoding

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Unity-Rate Coding Improves the iterative detection Convergence of Autoencoder-Aided Communication Systems

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2022年第5期71卷 5037-5047页

作者： Xiang, Luping Xu, Chao Zhang, Xiaoyu Van Luong, Thien Maunder, Robert G. Yang, Lie-Liang Hanzo, Lajos Univ Elect Sci & Technol China Sch Informat & Commun Engn Chengdu 611731 Peoples R China Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England Univ Southampton Optoelect Res Ctr Southampton SO17 1BJ Hants England

A forward error correction (FEC) and unity-rate coded (URC) autoencoder (AE)-assisted communication system is proposed for the first time, which relies on soft iterative decoding for attaining a vanishingly low error probability. The AE-demapper is specifically designed for directly calculating the extrinsic logarithmic likelihood ratios (LLRs), which can be directly entered into the URC decoder for soft iterative decoding. This avoids the potential degradation due to the conversion of symbol probabilities to bit LLRs. A comprehensive capacity analysis of the AE is performed, which demonstrates the capacity advantage of the AE-aided constellation design over its conventional quadrature amplitude modulation (QAM)/ phase shift keying (PSK) counterpart. Furthermore, we carry out its EXtrinsic Information Transfer (EXIT) chart analysis, which indicates that as a benefit of our URC, the EXIT curve always reaches the [1,1] point of perfect convergence, leading to a vanishingly low error probability. More explicitly, our bit error ratio (BER) and block error ratio (BLER) results demonstrate that the proposed FEC-URC-AE system achieves significant iterative gains both in additive white Gaussian noise (AWGN) and Rayleigh channels, outperforming both its model-based FEC-AE and its conventional coded QAM/QPSK counterparts.

关键词： iterative decoding decoding Communication systems Training Receivers Codes Forward error correction Unity-rate code (URC) autoencoder (AE) iterative detection and decoding EXtrinsic Information Transfer (EXIT) chart

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Dual-turbo receiver architecture for turbo coded MIMO-OFDM systems

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Science China(Information Sciences) 2012年第2期55卷 384-395页

作者： WANG WenJin1,GAO XiQi1,WU XiaoFu2,YOU XiaoHu1,ZHAO ChunMing1 & WONG Kai-Kit3 1National Communication Research Laboratory,Southeast University,Nanjing 210096,China 2Nanjing Institute of Communications Engineering,Nanjing 210007,China 3Department of Electrical and Electronic Engineering,University College London London WC1E 7JE,UK 1. National Communication Research Laboratory Southeast University Nanjing 210096 China2. Nanjing Institute of Communications Engineering Nanjing 210007 China3. Department of Electrical and Electronic Engineering University College London London WC1E 7JE UK

This paper presents a novel architecture of iterative receivers with two layers of iterations for turbo coded multiple-input and multiple-output orthogonal frequency-division multiplexing(MIMO-OFDM)systems,where soft messages are passed not only between the MIMO detector and the turbo decoder,but also between the two component decoders within the turbo *** first derive the factor graph representation of a turbo coded system as a basic building block for developing the iterative ***,a new soft message passing schedule over the factor graph is proposed,resulting in the proposed dual-turbo receiver architecture(DTRA).In DTRA,the MIMO detector and the turbo decoder work concurrently,and the soft messages for both layers of iterations are updated instantaneously,instead of the block-based exchange of soft messages in the conventional iterative *** so doing,the processing latency can be greatly reduced while low computational complexity can be achieved.

关键词： MIMO-OFDM iterative detection and decoding turbo codes

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