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multilevel generalised low-density parity-check codes

ELECTRONICS LETTERS 2006年第3期42卷 167-168页

作者： Tee, RYS Kuo, FC Hanzo, L Univ Southampton Dept Elect & Comp Sci Southampton SO17 1BJ Hants England

multilevel coding invoking generalised low-density parity-check component codes is proposed, which is capable of outperforming the classic low-density parity check component codes at a reduced decoding latency.

关键词： decoding parity check codes SNR improvement decoding latency generalizedlow-density parity-check codes multilevel coding

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Multi-dimensional space-time multilevel codes

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2006年第11期5卷 3287-3295页

作者： Martin, Philippa A. Rankin, David M. Taylor, Desmond P. Univ Canterbury Dept Elect & Comp Engn Christchurch 8020 New Zealand

To date there has been little work done on multilevel codes for the space-time environment. In this paper we develop multi-dimensional space-time multilevel codes (ST-MLCs). Several construction methods are proposed, including a coset code approach. The proposed space-time multilevel encoders partition a 2N(t)-dimensional signalling space, which spans all N-t transmit antennas. The multi-dimensional partitioning can be-designed to reduce the complexity of detection/decoding. We develop a space-time multistage decoder for the proposed ST-MLCs. It allows the complexity of soft decision decoding to be significantly reduced compared to a single level approach. In addition, significant performance gains over a single level approach are obtained.

关键词： space-time coding multilevel coding coset coding multistage decoding LDPC codes

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Channel combining and splitting for cutoff rate improvement

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IEEE TRANSACTIONS ON INFORMATION THEORY 2006年第2期52卷 628-639页

作者： Arikan, E Bilkent Univ Dept Elect Elect Engn TR-06800 Ankara Turkey

The cutoff rate R-0 (W) of a discrete memoryless channel (DMC) W is often used as a figure of merit alongside the channel capacity C(W). If a channel W is split into two possibly correlated subchannels W-1, W-2, the capacity function always satisfies C(W-1) + C(W-2): <= C(W), while there are examples for which R-0 (W-1) + R-0 (W-2) > R-0 (W). The fact that cutoff rate can be '' created '' by channel splitting was noticed by Massey in his study of an optical modulation system. This paper gives a general framework for achieving similar gains in the cutoff rate of arbitrary DMCs by methods of channel combining and splitting. The emphasis is on simple schemes that can be implemented in practice. We give several examples that achieve significant gains in cutoff rate at little extra system complexity. Theoretically, as the complexity grows without bound, the proposed framework is capable of boosting the cutoff rate of a channel to arbitrarily close to its capacity in a sense made precise in the paper. Apart from Massey's work, the methods studied here have elements in common with Forney's concatenated coding idea, a method by Pinsker for cutoff rate improvement, and certain coded-modulation techniques, namely, Ungerboeck's set-partitioning idea and Imai-Hirakawa multilevel coding;these connections are discussed in the paper.

关键词： channel combining channel splitting coded modulation concatenated coding cutoff rate error exponent multilevel coding random-coding exponent reliability exponent set partitioning successive cancellation decoding

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PERFORMANCE OF TWO LEVEL TURBO CODED 4-ARY CPFSK SYSTEMS OVER AWGN AND FADING CHANNELS

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ISTANBUL UNIVERSITY-JOURNAL OF ELECTRICAL AND ELECTRONICS ENGINEERING 2006年第1期6卷 107-111页

作者： Odabasioglu, Niyazi Istanbul Univ Engn Fac Elect & Elect Dept TR-34320 Istanbul Turkey

This paper presents performance of two level turbo coded 4-ary continuous phase frequency shift keying. In this system,, to provide phase continuity of the transmitted signals, turbo encoder and continuous phase encoder (CPE) are serially concatenated at the second level, while first level consist of only a turbo encoder. Simulation results are drawn for proposed system over AWGN, Rician and Rayleigh channels for three iterations while frame sizes are chosen as 100 and 1024. High error performances are obtained for proposed system compared to Trellis Coded CPFSK system

关键词： Turbo coding multilevel coding Continuous phase frequency shift keying

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multilevel-coded QAM with MIMO turbo-equalization in broadband single-carrier signaling

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2005年第3期54卷 954-966页

作者： Kansanen, K Schneider, C Matsumoto, T Thomä, R Univ Oulu Oulu 90014 Finland Tech Univ Ilmenau D-98684 Ilmenau Germany

A new scheme employing multilevel coded bit-interleaved transmission allowing for efficient turbo-equalization is proposed for multiple-input-multiple-output (MIMO) broadband single-carrier signaling. The proposed scheme is based on block-partitioned hierarchical constellations and offers robustness in data throughput efficiency against varying spatio-temporal characteristics of fading channels. The proposed scheme is compared to a standard bit-interleaved-coded-modulation (BICM) system in frequency-selective channels, and found to offer better overall throughput. It is also shown that level-wise retransmission control with the proposed multilevel single-carrier signaling scheme can offer further throughput improvement. Channel measurement-based simulations are used to evaluate performances of both schemes in real fields. Channel parameter analysis using a superresolution technique is performed to clarify the underlying reasons for the performance characteristics of the systems.

关键词： automatic repeat-request bit-interleaved modulation multilevel coding multiple-input-multiple-output (MIMO) systems throughput efficiency turbo equalization

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Noncoherent block-coded MPSK

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IEEE TRANSACTIONS ON COMMUNICATIONS 2005年第6期53卷 978-986页

作者： Wei, RY Natl Cent Univ Dept Commun Engn Chungli 320 Taiwan

For coherent detection, block-coded modulation is a bandwidth efficient scheme. In this paper, we propose theorems about the error performance of block-coded modulation using M-ary phase-shift keying (MPSK) for noncoherent detection. Based on these theorems, we propose a novel block-coded modulation scheme for noncoherent detection called noncoherent block-coded MPSK. The proposed scheme provides flexible designs of noncoherent block codes with different code rate, block length and error performance. Good noncoherent block codes can be easily obtained by properly choosing binary linear block codes as the component codes. Moreover, noncoherent block codes of this new scheme can be decoded by multistage decoding, which has the advantage of low complexity and satisfactory error performance. In this paper, two algorithms of multistage decoding for noncoherent detection are proposed as well. The error performance of some designed codes and decoding algorithms is verified by computer simulation.

关键词： block-coded modulation multilevel coding non-coherent detection phase-shift keying (PSK)

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On coded modulation using LDPC convolutional codes

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2005年第4期59卷 254-257页

作者： Pittermann, J Lentmaier, M Zigangirov, KS Univ Notre Dame Dept Elect Engn Notre Dame IN 46556 USA Univ Ulm Dept Informat Technol D-89081 Ulm Germany

A new construction combining LDPC convolutional codes and multilevel coding/modulation is suggested and analyzed. In the case of QPSK, we demonstrate that it has a better performance than an LDPC convolutional code co... 详细信息

关键词： LDPC convolutional codes multilevel coding gray mapping combined demodulation/decoding

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N/C detector and multistage receiver for coded signals over MIMO channels: performance and optimization

N/C detector and multistage receiver for coded signals over ...

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IEEE International Conference on Communications (ICC 2005)

作者： Choi, JH Univ New S Wales Sch Elect Engn & Telecomm Sydney NSW 2052 Australia

ISBN: (纸本)0780389387

In this paper, we address some performance issues of multiple input multiple output (MIMO) channels with a nulling and cancellation (N/C) detector, which is based on the QR factorization. We find a theoretical bit error rate (BER) expression. The concept of multilevel coding has been adopted for optimizing the performance of a multistage receiver with the N/C detector when a channel code is employed. Through simulations, the performance has been studied for coded signals. It has been shown that the optimization of code rate for each layer is an effective means to improve the performance when the multistage receiver is employed.

关键词： space-time architecture milling and cancellation detection multistage receiver multilevel coding

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Coded modulation using superimposed binary codes

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IEEE TRANSACTIONS ON INFORMATION THEORY 2004年第12期50卷 3331-3343页

作者： Ma, X Li, P City Univ Hong Kong Dept Elect Engn Kowloon 510275 Hong Kong Peoples R China Sun Yat Sen Univ Dept Elect & Commun Engn Guangzhou 510275 Peoples R China City Univ Hong Kong Dept Elect Engn Kowloon Hong Kong Peoples R China

In this correspondence, we investigate in a comprehensive fashion a one-layer coding/shaping scheme resembling a perfectly cooperated multiple-access system. At the transmitter, binary data are encoded by either single-level or multilevel codes. The coded bits are first randomly interleaved and then entered into a signal mapper. At each time, the signal mapper accepts as input multiple binary digits and delivers as output an amplitude signal, where the input are first independently mapped into 2-PAM signals (possibly having different amplitudes) and then superimposed to form the output. The receiver consists of an iterative decoding/demapping algorithm with an entropy-based stopping criterion. In the special cases when all the 2-PAM signals have equal amplitudes, based on an irregular trellis, we propose an optimal soft-input-soft-output (SISO) demapping algorithm with quadratic rather than exponential complexity. In the general cases, when multilevel codes are employed, we propose power-allocation strategies to facilitate the iterative decoding/dempaping algorithm. Using the unequal power-allocations and the Gaussian-approximation-based suboptimal demapping algorithm (with linear complexity), coded modulation with high bandwidth efficiency can be implemented.

关键词： Coded modulation sigma-mapping coding/shaping scheme iterative decoding/demapping algorithm iterative multistage decoding multilevel coding soft-input soft-output (SISO) demapping algorithm

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Two-Level Unequal Error Protection Scheme in Image Transmission System Using multilevel Codes in Rayleigh Fading Channel

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The Journal of China Universities of Posts and Telecommunications 2004年第z1期11卷 55-61页

作者： LI Zuo-wei~1, YANG Yi-xian~1, YUAN Dong-feng~2, HU Zheng-ming~1 1.Information Security Center,Beijing University of Posts and Telecommunications, Beijing 100876, P.R. China 2.School of Information Science and Engineering, Shandong University, Jinan 250100, P.R. China Information Security Center Beijing University of Posts and Telecommunications Beijing 100876 P.R. China School of Information Science and Engineering Shandong University Jinan 250100 P.R. China

In this paper, we propose a novel Unequal Error Protection (UEP) scheme with two levels for image transmission using multilevel Codes (MLC). By providing the best protection for the most important data, the final recovered image quality is remarkably improved both in visual effect and in Peak Signal to Noise power Ratio (PSNR) performance.

关键词： rayleigh fading channel image transmission inequal error protection multilevel coding

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