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code design for combined channel estimation and error protection

IEEE TRANSACTIONS ON INFORMATION THEORY 2002年第5期48卷 1162-1171页

作者： Skoglund, M Giese, J Parkvall, S Royal Inst Technol Dept Signals Senors & Syst SE-10044 Stockholm Sweden

We consider the problem of data transmission over a linear-filter channel with an unknown filter response. Traditionally, the various operations (equalization, detection, decoding) carried out by the receiver of a system that operates over an unknown channel assume access to high-quality estimates of the channel parameters. Such estimates are typically computed by a separate device for channel identification. In contrast, this paper focuses on combined channel estimation, equalization, and decoding. We also study the problem of code design, assuming such combined decoding. More precisely, we investigate nonlinear block coding and present a design criterion and a design algorithm, under the assumptions that a statistical description of the channel is available, and that the structure of the decoder is known to the transmitter. Numerical simulations demonstrate that the new scheme is capable of outperforming four different benchmark schemes.

关键词： block coding channel estimation code design equalization frequency-selective fading intersymbol interference joint decoding

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code design and interception probability of optical fibre communication system based on optical coding

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IET COMMUNICATIONS 2022年第14期16卷 1731-1738页

作者： Liu, Mandong Ji, Jianhua Wang, Ke Xu, Ming Shenzhen Univ Coll Elect & Informat Engn Shenzhen 518060 Peoples R China

Traditional optical orthogonal code has small code cardinality, which is vulnerable to the brute-force attacks by eavesdroppers. In order to improve the anti-interception performance of optical fibre communication system based on optical coding, a new family of optical code with large code cardinality is proposed. Based on information-theoretic security, the interception probability of optical fibre coding system is proposed and defined, and the expression of the interception probability is derived for the first time. The influences of extraction distance, extraction ratio, the number of interfering users and the code length on the interception probability are analysed quantitatively. The anti-interception performance of the optical coding system is investigated by numerical analysis and OptiSystem simulation. It is shown that reliability and anti-interception performance can be achieved simultaneously by selecting appropriate code parameters and the number of interfering users.

关键词： optical code code length optical coding system code cardinality anti-interception performance optical fibre coding system traditional optical orthogonal code probability telecommunication security interception probability optical fibre communication system orthogonal codes optical fibre communication code design

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code design for rank-deficient correlated channels

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ELECTRONICS LETTERS 2005年第21期41卷 1187-1188页

作者： Kazemitabar, J Jafarkhani, H Ekbatani, S Univ Calif Irvine Dept Elect Engn & Comp Sci Irvine CA 92697 USA

design criterion for i.i.d. MIMO channels is well-known, and a large body of literature is found on codes designed for these channels. However. in reality there is usually correlation between antennas. Reviewed is the performance of a modulation scheme in a spatially correlated channel. Proposed is a systematic method to design codes that achieve maximum diversity of that channel as well as keeping other good properties of a code, such as higher rate, lower decoding complexity, and unit peak-to-average power ratio for equi-magnitude constellations.

关键词： MIMO systems channel coding diversity reception space-time codes MIMOchannels channel diversity code design equi-magnitude constellations modulation scheme rank-deficient correlated channels spatially correlated channel

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code design and Shuffled Iterative Decoding of a Quasi-Cyclic LDPC coded OFDM System

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Tsinghua Science and Technology 2009年第1期14卷 106-112页

作者：刘斌彬白栋葛启宏梅顺良 Department of Electronic Engineering Tsinghua University Department of Electronics Peking University

In multipath environments, the error rate performance of orthogonal frequency division multiplexing （OFDM） is severely degraded by the deep fading subcarriers. Powerful error-correcting codes must be used with OFDM. This paper presents a quasi-cyclic low-density parity-check （LDPC） coded OFDM system, in which the redundant bits of each codeword are mapped to a higher-order modulation constellation. The op- timal degree distribution was calculated using density evolution. The corresponding quasi-cyclic LDPC code was then constructed using circulant permutation matrices. Group shuffled message passing scheduling was used in the iterative decoding. Simulation results show that the system achieves better error rate performance and faster decoding convergence than conventional approaches on both additive white Gaussian noise （AWGN） and Rayleigh fading channels.

关键词： quasi-cyclic low-density parity-check (LDPC) codes code design iterative decoding degree distribution density evolution

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Outage performance and IRA code design for MIMO block fading with unitary scrambling

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2008年第4期57卷 2354-2363页

作者： Yue, Guosen Wang, Xiaodong Madihian, Mohammad NEC Labs Amer Inc Princeton NJ 08540 USA Columbia Univ Dept Elect Engn New York NY 10027 USA

We consider coded multiple-input-multiple-output (MIMO) systems in block-fading channels employing iterative receivers, where the MIMO channels are scrambled by unitary matrices. We show that the unitary scrambling improves the outage performance with discrete input when the outer code rate is high, i.e., R-o > 0.5. We also demonstrate that the performance improvement from scrambling can be achieved by a small number of random unitary matrices. Moreover, with unitary scrambling, the signal model can be simplified, and the performance of the MIMO demodulator can be characterized by the singular values of the channel matrix. We then consider the design of irregular repeat-accumulate (IRA) codes for unitary scrambled MIMO block-fading channels. We propose a code design method by optimizing the IRA codes for EXtrinsic Information Transfer (EXIT) average with a given effective mutual information. We also propose a pessimistic code design for some system settings to improve the frame error rate performance.

关键词： block fading code design irregular repeat-accumulate (IRA) code multiple-input-multiple-output (MIMO) outage analysis unitary scrambling

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An Information-Theoretic Perspective on Successive Cancellation List Decoding and Polar code design

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IEEE TRANSACTIONS ON INFORMATION THEORY 2022年第9期68卷 5779-5791页

作者： Coskun, Mustafa Cemil Pfister, Henry D. Inst Commun & Nav German Aerosp Ctr DLR D-82234 Wessling Germany Duke Univ Dept Elect & Comp Engn Durham NC 27708 USA Tech Univ Munich Inst Commun Engn LNT D-80333 Munich Germany

This work identifies information-theoretic quantities that are closely related to the required list size on average for successive cancellation list (SCL) decoding to implement maximum-likelihood decoding over general binary memoryless symmetric (BMS) channels. It also provides upper and lower bounds for these quantities that can be computed efficiently for very long codes. For the binary erasure channel (BEC), we provide a simple method to estimate the mean accurately via density evolution. The analysis shows how to modify, e.g., Reed-Muller codes, to improve the performance when practical list sizes, e.g., L is an element of [8, 1024], are adopted. Exemplary constructions with block lengths N is an element of {128, 512} outperform polar codes of 5G over the binary-input additive white Gaussian noise channel. It is further shown that there is a concentration around the mean of the logarithm of the required list size for sufficiently large block lengths, over discrete-output BMS channels. We provide the probability mass functions (p.m.f.s) of this logarithm, over the BEC, for a sequence of the modified RM codes with an increasing block length via simulations, which illustrate that the p.m.f.s concentrate around the estimated mean.

关键词： Successive cancellation list decoding Reed-Muller codes polar codes dynamic frozen bits code design

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LDPC code design for the Two-User Gaussian Multiple Access Channel

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2016年第4期15卷 2833-2844页

作者： Sharifi, Shahrouz Tanc, A. Korhan Duman, Tolga M. Arizona State Univ Sch Elect Comp & Energy Engn ECEE Tempe AZ 85287 USA Maxlinear Carlsbad CA USA Kirklareli Univ Dept Elect & Elect Engn TR-39100 Kayali Kirklareli Turkey Bilkent Univ Dept Elect & Elect Engn TR-06800 Ankara Turkey

We study code design for two-user Gaussian multiple access channels (GMACs) under fixed channel gains and under quasi-static fading. We employ low-density parity-check (LDPC) codes with BPSK modulation and utilize an iterative joint decoder. Adopting a belief propagation (BP) algorithm, we derive the PDF of the log-likelihood-ratios (LLRs) fed to the component LDPC decoders. Via examples, it is illustrated that the characterized PDF resembles a Gaussian mixture (GM) distribution, which is exploited in predicting the decoding performance of LDPC codes over GMACs. Based on the GM assumption, we propose variants of existing analysis methods, named modified density evolution (DE) andmodified extrinsic information transfer (EXIT). We derive a stability condition on the degree distributions of the LDPC code ensembles and utilize it in the code optimization. Under fixed channel gains, the newly optimized codes are shown to perform close to the capacity region boundary outperforming the existing designs and the off-the-shelf point-to-point (P2P) codes. Under quasi-static fading, optimized codes exhibit consistent improvements upon the P2P codes as well. Finite block length simulations of specific codes picked from the designed ensembles are also carried out and it is shown that optimized codes perform close to the outage limits.

关键词： Low-density parity-check codes code design multiple access channels iterative decoding Gaussian mixture common outage capacity

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Unified Optimization Framework for Multi-Static Radar code design Using Information-Theoretic Criteria

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2013年第21期61卷 5401-5416页

作者： Naghsh, Mohammad Mahdi Modarres-Hashemi, Mahmoud ShahbazPanahi, Shahram Soltanalian, Mojtaba Stoica, Petre Isfahan Univ Technol Dept Elect & Comp Engn Esfahan *** Iran Univ Ontario Inst Technol Fac Engn & Appl Sci Toronto ON L1H 7K4 Canada Uppsala Univ Dept Informat Technol SE-75105 Uppsala Sweden

In this paper, we study the problem of code design to improve the detection performance of multi-static radar in the presence of clutter (i.e., a signal-dependent interference). To this end, we briefly present a discrete-time formulation of the problem as well as the optimal detector in the presence of Gaussian clutter. Due to the lack of analytical expression for receiver operation characteristic (ROC), code design based on ROC is not feasible. Therefore, we consider several popular information-theoretic criteria including Bhattacharyya distance, Kullback-Leibler (KL) divergence, J-divergence, andmutual information (MI) as design metrics. The code optimization problems associated with different information-theoretic criteria are obtained and cast under a unified framework. We propose two general methods based on Majorization-Minimization to tackle the optimization problems in the framework. The first method provides optimal solutions via successive majorizations whereas the second one consists of a majorization step, a relaxation, and a synthesis stage. Moreover, derivations of the proposed methods are extended to tackle the code design problems with a peak-to-average ratio power (PAR) constraint. Using numerical investigations, a general analysis of the coded system performance, computational efficiency of the proposed methods, and the behavior of the information-theoretic criteria is provided.

关键词： code design information-theoretic criteria multi-static radar majorization-minimization peak-to-average power ratio (PAR)

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LDPC code design Considerations for Non-Uniform Channels

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IEEE TRANSACTIONS ON COMMUNICATIONS 2010年第1期58卷 101-109页

作者： Sanaei, Ali Ardakani, Masoud Univ Alberta Dept Elect & Comp Engn Edmonton AB T6G 2V4 Canada

Irregular low-density parity-check (LDPC) code design for parallel sub-channels with different qualities is investigated. Such channels appear in many communication systems, e. g., orthogonal frequency-division multiplexing systems. When channel knowledge is available at both the transmitter and receiver, following the literature, we consider allotted LDPC codes which carefully assign different parts of the code to sub-channels. To reduce the number of design parameters and allow for efficient design, semi-regular allotted codes have been suggested. We first formulate the design of semi-regular codes as a mixed integer linear programming. Relaxing the semi-regularity constraint broadens the search space which results in improved codes and also a more efficient design via linear programming. While information theoretic results suggest that having channel state information-for a fixed power assignment-does not change the capacity, we show that under non-optimal decoding or when the maximum degree allowed in the code is small, allotted codes significantly outperform conventional ones. Finally, for the case that neither side has the channel knowledge (thus capacity-loss is inevitable), we see that the reduced capacity can still be approached by LDPC codes.

关键词： Non-uniform channels irregular low-density parity-check codes code design discrete multi-tone systems OFDM systems allotted LDPC code mixed integer programming linear programming

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Near-Field Passive RFID Communication: Channel Model and code design

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IEEE TRANSACTIONS ON COMMUNICATIONS 2014年第5期62卷 1716-1727页

作者： Barbero, Angela I. Rosnes, Eirik Yang, Guang Ytrehus, Oyvind Univ Valladolid Dept Matemat Aplicada E-47011 Valladolid Spain Univ Bergen Dept Informat Selmer Ctr N-5020 Bergen Norway Simula Res Lab Oslo Norway

This paper discusses a new channel model and code design for the reader-to-tag channel in near-field passive radio frequency identification (RFID) systems using inductive coupling as a power transfer mechanism. If the receiver resynchronizes its internal clock each time a bit is detected, the bit-shift channel used previously in the literature to model the reader-to-tag channel needs to be modified. In particular, we propose a discretized Gaussian shift channel as a new channel model in this scenario. We introduce the concept of quantifiable error avoidance, which is much simpler than error correction. The capacity is computed numerically, and we also design some new simple codes for error avoidance on this channel model based on insights gained from the capacity calculations. Finally, some simulation results are presented to compare the proposed codes to the Manchester code and two previously proposed codes for the bit-shift channel model.

关键词： Bit-shift channel channel capacity code design coding for error avoidance constrained coding discretized Gaussian shift channel inductive coupling radio frequency identification (RFID) reader-to-tag channel synchronization errors

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