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8th International Symposium on Medical Information and Communication Technology (ISMICT)

作者： Lyu, Yibo Cai, Guofa Wang, Lin Xiamen Univ Dept Commun Engn Xiamen 361005 Fujian Peoples R China

ISBN: (纸本)9781479948550

In this article, an iterative demodulation and decoding receiver for M-ary differential chaos shift keying (DSCK) modulation is proposed over Additive White Gaussian Noise (AWGN) channel. The Log-Likelihood Ratios (LLRs) of coherent DCSK demodulator and decoder are derived assuming that its perfect carrier synchronization happened. The simulation results show that the performance of our proposed iterative receiver outperform that of the noniterative receiver over AWGN channel due to extrinsic information exchanged between demodulator and decoder. Furthermore, Extrinsic Information Transfer chart is used to investigate the convergence behavior of our proposed receiver.

关键词： DCSK coherent demodulation LDPC codes iterative demodulation and decoding Extrinsic information transfer (EXIT) chart

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Study on iterative demodulation and decoding for Short-wave Frequency-Hopped OFDM System

Study on Iterative Demodulation and Decoding for Short-wave ...

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3rd International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM 2007)

作者： Xiong Junqiao Wu Qiongli Gan Liangcai Zhu Yichao Wuhan Univ Sch Elect Informat Wuhan 430079 Peoples R China

ISBN: (纸本)9781424413119

According to the characteristic of short-wave Frequency-Hopped (FH) communication, an OFDM/FH system based on iterative demodulation and decoding is proposed. By combining the advantage of NSD technique and iterative demodulation and decoding, the method could compensate the SNR loss caused by differential modulation and improve the reliability of short-wave communication and improve the system reliability) Numeric simulation results show that the proposed method could effectively improve the system BER performance and reach good transmission efficiency.

关键词： iterative demodulation and decoding NSD OFDM Frequency-Hopped

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A NEW METHOD OF iterative DIFFERENTIAL demodulation AND decoding FOR SCCC-CODED SYSTEMS 12

A NEW METHOD OF ITERATIVE DIFFERENTIAL DEMODULATION AND DECO...

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12th International Computer Conference on Wavelet Active Media Technology and Information Processing (ICCWAMTIP)

作者： Xie, Si-Lin Zhang, Bang-Ning Wang, Xi Guo, Dao-Xing PLA Univ Sci & Technol Inst Commun Engn Nanjing 210007 Jiangsu Peoples R China 714 Factory Nanjing 210007 Jiangsu Peoples R China

ISBN: (纸本)9781467382663

Researches on the application of iterative differential demodulation and decoding in SCCC-coded systems are presented. Knowing that the tradition algorithm of iterative decoding in SCCC-coded systems has a high complexity with a two-level iteration structure, a low complexity approach is proposed. In each iteration of the channel decoding, the demodulator uses the extrinsic information of the outer decoder of the channel decoder as apriori information to make a soft decision to update the codewords. As a result, the 'turbo processing' of both the entirety iteration and the inner iteration of channel decoder is simplified to a single-level iterative system. It is shown that iterative demodulation and decoding can effectively improve the performance of the systems. The optimized single-level method almost keeps the similar performance and reduces the complexity significantly.

关键词： Differential demodulation SCCC code iterative demodulation and decoding complexity

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A NEW METHOD OF iterative DIFFERENTIAL demodulation AND decoding FOR SCCC-CODED SYSTEMS

A NEW METHOD OF ITERATIVE DIFFERENTIAL DEMODULATION AND DECO...

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International Copmputer Conference on Wavelet Active Miedia Technology and Information Processing

作者： SI-LIN XIE BANG-NING ZHANG XI WANG DAO-XING GUO Institute of Communications Engineering PLA University of Science and Technology Nanjing 210007 China

ISBN: (纸本)9781467382670

Researches on the application of iterative differential demodulation and decoding in SCCC-coded systems are presented. Knowing that the tradition algorithm of iterative decoding in SCCC-coded systems has a high complexity with a two-level iteration structure, a low complexity approach is proposed. In each iteration of the channel decoding, the demodulator uses the extrinsic information of the outer decoder of the channel decoder as a priori information to make a soft decision to update the codewords. As a result, the 'turbo processing' of both the entirety iteration and the inner iteration of channel decoder is simplified to a single-level iterative system. It is shown that iterative demodulation and decoding can effectively improve the performance of the systems. The optimized single-level method almost keeps the similar performance and reduces the complexity significantly.

关键词： Differential demodulation SCCC code iterative demodulation and decoding complexity

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Performance bounds in convolutional coded parallel combinatorial SS systems

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2002年第7期E85A卷 1696-1701页

作者： Takizawa, K Sasaki, S Muramatsu, S Zhou, J Kikuchi, H Niigata Univ Dept Elect & Elect Engn Niigata 9502181 Japan

Upper bounds on the bit error rate (BER) for maximum likelihood (ML) decoding are derived in convolutional coded parallel combinatorial spread spectrum (PC/SS) systems over additive white Gaussian noise (AWGN) channels. PC/SS systems can achieve higher data transmission than conventional multicode SS systems. To make the derivation tractable, we put a uniform interleaver between a convolutional encoder and a PC/SS transmitter. Since the PC/SS transmitter is employed as the "inner encoder," the bounds are obtained in a similar manner of the derivation in serially concatenated codes through a uniform interleaver. Two different error patterns in the PC/SS system are considered in the performance analysis. Numerical results show that the derived BER bounds are sufficiently accurate. It is found that the coded PC/SS systems outperform coded all-code-parallel DS/SS systems under the same data rate conditions if the number of pre-assigned PN codes increases.

关键词： multicode SS convolutional codes iterative demodulation and decoding

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Reduced-complexity demodulation for MIMO-BICM-IDD using modified stack algorithms

Reduced-complexity demodulation for MIMO-BICM-IDD using modi...

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32nd IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Nekuii, Mehran Davidson, Timothy N. McMaster Univ Dept Elect & Comp Engn Hamilton ON Canada

ISBN: (纸本)1424407281

Bit-interleaved coded-modulation (BICM) with iterative demodulation and decoding (IDD) is a popular architecture for the development of practical communication schemes that operate at rates close to capacity. In multiple-input multiple-output (MIMO) BICM-IDD schemes, a key computational bottleneck is the demodulation step;that is, the extraction of "soft" information about the transmitted bits from the channel output. The concept of list-based demodulation provides a convenient framework for managing the trade-off between accuracy and computational cost in the extraction of this soft information, especially when tree-search techniques are used to construct the list. In this paper, we will propose several list-based demodulators based on modifications of the stack algorithm for searching a tree. The modifications partition the stack in ways that enable efficient and effective searching of the tree from the perspective of list-based demodulation. Simulation results show that the proposed demodulators achieve desirable trade-offs between complexity and performance.

关键词： MIMO demodulation iterative demodulation and decoding stack algorithm

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Efficient soft demodulation of MIMO QPSK via semidefinite relaxation

Efficient soft demodulation of MIMO QPSK via semidefinite re...

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33rd IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Nekuii, Mehran Kisialiou, Mikalai Davidson, Timothy N. Luo, Zhi-Quan McMaster Univ Dept Elect & Comp Engn Hamilton ON Canada Univ Minnesota Dept Elect & Comp Engn Minneapolis MN 55414 USA Intel Corp Portland OR 97208 USA

ISBN: (纸本)9781424414833

We develop a computationally efficient and memory efficient approach to (near) maximum a posteriori probability demodulation for MIMO systems with QPSK signalling, based on semidefinite relaxation. Existing approaches to this problem require either storage of a large list of candidate bit-vectors, or the solution of multiple binary quadratic problems. In contrast, the proposed demodulator does not require the storage of a candidate list, and involves the solution of a single (efficiently solvable) semidefinite program per channel use. Our simulation results show that the resulting computational and memory efficiencies are obtained without incurring a significant degradation in performance.

关键词： MIMO soft demodulation bit-interleaved coded modulation iterative demodulation and decoding semidefinite relaxation

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A Noncoherent Coded MPSK Scheme with Near-Capacity Performance for Channels with Fast Phase Variation

A Noncoherent Coded MPSK Scheme with Near-Capacity Performan...

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2010 IEEE 71st Vehicular Technology Conference

作者： Chen, Yen-Ming Ueng, Yeong-Luh Chao, Ying-Chen Natl Tsing Hua Univ Dept Elect Engn Hsinchu Taiwan

ISBN: (纸本)9781424425198

In this paper, we propose to approach the capacity limit for channels with fast phase variation by using a serial concatenation scheme with an outer turbo encoder and an inner block modulator. A distinct feature of the proposed transmission scheme is that coded symbols from adjacent codewords are interleaved into the same input vectors of the block modulator. At the receiver, we not only perform the iterative noncoherent demodulation and decoding algorithm, but also exchange extrinsic information between adjacent codewords due to the codeword interleaved structure. It is shown through the extrinsic information transfer (EXIT) chart that the resultant block demodulator and channel decoder can match well with each other, and can achieve a near-capacity performance.

关键词： iterative demodulation and decoding noncoherent AWGN channel turbo principle

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Optimization Design of C²PM with Short Frame and its Implementation

Optimization Design of C<SUP>2</SUP>PM with Short Frame and ...

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IEEE Wireless Communications and Networking Conference (WCNC)

作者： Dai, Xiaojie Zhan, Yafeng Zhang, Ruyuan Tsinghua Univ Space Ctr Beijing 100084 Peoples R China

ISBN: (纸本)9781467359399;9781467359382

Serially coded and interleaved continuous phase modulation ((CPM)-P-2) with iterative demodulation and decoding is investigated for burst communication. The optimization and simplified decoding for (CPM)-P-2 system with short frame are discussed, including simplified demodulator and matched interleaver. Simulation results show that for coded GMSK system under AWGN, the performance is better than individual convolutional code. Especially when BER is 1x10(-5), it performs better than Turbo code and LDPC code with the same frame length, and there is no error floor occurring. Complexity analysis shows that the coded GMSK system has lower implementation complexity in comparison with Turbo and LDPC code. Moreover, efficient hardware implementation based on Xilinx Vertex-4 FPGA platform is presented. The practical performances prove that this system is suitable for burst communication.

关键词： (CPM)-P-2 short frame coded GMSK iterative demodulation and decoding

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Layered LDPC decoding for Turbo-Differential decoding in Presence of Cycle Slips in Optical Communications 18

Layered LDPC Decoding for Turbo-Differential Decoding in Pre...

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18th International Conference on Transparent Optical Networks (ICTON)

作者： Cabirol, Christian Sauer-Greff, Wolfgang Urbansky, Ralph Univ Kaiserslautern Chair Communicat Syst D-67663 Kaiserslautern Germany

ISBN: (纸本)9781509014675

In optical communication systems using wavelength division multiplexing, the transmission link can no longer be described as an AWGN channel as the co-propagating signals influence each other due to the nonlinearity of the fiber. As a consequence of the resulting phase noise, frequent cycle slips may occur in the carrier phase estimation which can be counteracted by the use of differential modulation. To mitigate random transmission errors, state-of-the-art Low-Density Parity-Check (LDPC) codes are for large coding gains. The differential decoding penalty due to error doubling can be reduced by iterative demodulation and decoding. For AWGN channels, this penalty is almost entirely recoverable. However, cycle slips induce contradictions of the received channel sequence and the a-priori information from the LDPC decoder in the differential demodulation process leading to non-negligible error floors. We show that using so-called layered LDPC decoding, the number of required iterations for iterative demodulation and decoding can be reduced and the sensitivity towards cycle slips can be improved.

关键词： iterative demodulation and decoding layered LDPC decoding differential modulation cycle slips

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