Following the increasing interest in non-binary coding schemes, turbocodes over different Galois fields have started to be considered recently. While showing improved performance when compared to their binary counter...
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ISBN:
(纸本)9781538670484
Following the increasing interest in non-binary coding schemes, turbocodes over different Galois fields have started to be considered recently. While showing improved performance when compared to their binary counterparts, the decoding complexity of this family of codes remains a main obstacle to their adoption in practical applications. In this work, a new low-complexity variant of the Min-Log-MAP algorithm is proposed. Thanks to the introduction of a bubble sorter for the different metrics used in the Min-Log-MAP decoder, the number of required computations is significantly reduced. A reduction by a factor of 6 in the number of additions and compare-select operations can be achieved with only a minor impact on error rate performance. With the use of an appropriate quantization, the resulting decoder paves the way for a future hardware implementation.
In this paper, we investigate and compare the asymptotic performance of concatenated convolutional coding schemes over GF(4) over additive white Gaussian noise (AWGN) channels. Both parallel concatenated codes (PCC) a...
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In this paper, we investigate and compare the asymptotic performance of concatenated convolutional coding schemes over GF(4) over additive white Gaussian noise (AWGN) channels. Both parallel concatenated codes (PCC) and serial concatenated codes (SCC) are considered. We construct such codes using optimal non-binary convolutional codes where optimality is in the sense of achieving the largest minimum distance for a fixed number of encoder states. Code rates of the form k(0)/(k(0) + 1) for k(0) = 1, 8, and 64 are considered, which suite a wide spectrum of communications applications. For all of these code rates, we find the minimum distance and the corresponding multiplicity for both concatenated code systems. This is accomplished by feeding the encoder with all possible weight-two and weight-three input information patterns and monitoring, at the output of the encoder, the weight of the corresponding codewords and their multiplicity. Our analytical results indicate that the SCC codes considerably outperform their counterpart PCC codes at a much lower complexity. Inspired by the superiority of SCC codes, we also discuss a mathematical approach for analysing such codes, leading to a more comprehensive analysis and allowing for further improvement in performance by giving insights on designing a proper interleaver that is capable of eliminating the dominant error patterns. Copyright (C) 2004 John Wiley Sons, Ltd.
A method to compute the truncated union bound of non-binary turbo codes mapped to high order modulations is proposed in this letter. It calls for the estimate of the truncated Euclidean distance spectrum. To this end,...
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A method to compute the truncated union bound of non-binary turbo codes mapped to high order modulations is proposed in this letter. It calls for the estimate of the truncated Euclidean distance spectrum. To this end, we identify the error events that limit the Euclidean distance of non-binary turbo codes based on memory-1 convolutional codes defined over GF (q) , q>2 . Application examples are elaborated for codes over GF(64). The resulting bounds are found to accurately predict the asymptotic performance of the coded modulation scheme.
non-binary turbo codes have been shown to out-perform their binary counterparts in terms of error correcting performance yet the decoding complexity of the commonly used MM-Log-MAP algorithm prohibits efficient hardwa...
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ISBN:
(纸本)9781665409438
non-binary turbo codes have been shown to out-perform their binary counterparts in terms of error correcting performance yet the decoding complexity of the commonly used MM-Log-MAP algorithm prohibits efficient hardware implementations. In this work, we apply for the first time the recently proposed Local SOYA algorithm for decoding non-binary turbo codes. Moreover, we propose a low complexity variant dedicated to the direct association with high order constellations denoted by the nearest neighbor Local SOYA. It considers only a limited amount of nearest competing constellation symbols for the soft output computation. Simulation results show that this approach allows a complexity reduction of up to 52% in terms of addcompare-select operations while maintaining the same error correcting performance compared to the MM-Log-MAP algorithm. It can even reach up to 80% if high code rates or frame error rates higher than 10(-4) are targeted. The achieved complexity reduction represents a significant step forward towards hardware implementation.
The power-line communication (PLC) channel causes information-bearing signals to be affected by impulsive noise and the effects of the multipath fading. To mitigate these effects, we propose the employment of non-bina...
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ISBN:
(纸本)9780992862671
The power-line communication (PLC) channel causes information-bearing signals to be affected by impulsive noise and the effects of the multipath fading. To mitigate these effects, we propose the employment of non-binary turbo codes, since non-binary error-correcting codes generally promise an enhanced performance in such harsh environments. In this paper, we investigate the performance of non-binaryturbo-codes on PLC channels that exhibit frequency selectivity with additive Middleton Class A noise and compare with a comparable binaryturbo-coded PLC system. In order to reduce the effect of multipath and impulsive noise, orthogonal frequency-division multiplexing (OFDM) with non-linear receivers (blanking and clipping) have been employed. The system is examined on extremely impulsive channels where the value of the impulsive index (A) is 0.01 and the noise ratio (Gamma) is 0.01. The results show that non-binary turbo codes are very robust and achieve a large gain over binaryturbocodes on PLC channels.
non-binary turbo codes (TCs) have become an important class of TCs following the adoption of duo-binary TCs (DBTCs) in the digital video broadcasting with return channel via satellite (DVB-RCS) standard. Several hiera...
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non-binary turbo codes (TCs) have become an important class of TCs following the adoption of duo-binary TCs (DBTCs) in the digital video broadcasting with return channel via satellite (DVB-RCS) standard. Several hierarchical modulation (HM) schemes for binary TCs have been proposed with a view to enhancing their performance. However, the existing techniques make use of fixed parameters throughout the E-b/N-0 range and have not been applied to non-binary TCs. In this paper, optimum parameters have been derived from exhaustive simulations for performing HM with 8-PSK integrated with DBTCs. To validate the improved error performances obtained with the optimized parameters for HM, EXIT charts have been generated. Moreover, a model that could predict the optimized parameters at each E-b/N-0 using K-nearest neighbor (K-NN)-based binary classification has been derived from the results of exhaustive simulations. Significant improvement in error performances have been observed with the proposed scheme. For example, with a couple length of 48, code rate of 1/3 or 1/2, and 8-PSK modulation, a significant average gain of 0.5dB is obtained over conventional DBTCs without HM.
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