Journal ArticleDOI
Channel coding with multilevel/phase signals
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TLDR
A coding technique is described which improves error performance of synchronous data links without sacrificing data rate or requiring more bandwidth by channel coding with expanded sets of multilevel/phase signals in a manner which increases free Euclidean distance.Abstract:
A coding technique is described which improves error performance of synchronous data links without sacrificing data rate or requiring more bandwidth. This is achieved by channel coding with expanded sets of multilevel/phase signals in a manner which increases free Euclidean distance. Soft maximum--likelihood (ML) decoding using the Viterbi algorithm is assumed. Following a discussion of channel capacity, simple hand-designed trellis codes are presented for 8 phase-shift keying (PSK) and 16 quadrature amplitude-shift keying (QASK) modulation. These simple codes achieve coding gains in the order of 3-4 dB. It is then shown that the codes can be interpreted as binary convolutional codes with a mapping of coded bits into channel signals, which we call "mapping by set partitioning." Based on a new distance measure between binary code sequences which efficiently lower-bounds the Euclidean distance between the corresponding channel signal sequences, a search procedure for more powerful codes is developed. Codes with coding gains up to 6 dB are obtained for a variety of multilevel/phase modulation schemes. Simulation results are presented and an example of carrier-phase tracking is discussed.read more
Citations
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Proceedings ArticleDOI
Non-binary adaptive LDPC codes for frequency selective channels: code construction and iterative decoding
TL;DR: A new type of non-binary LDPC codes defined over multiple Galois fields that can adapt to the profile of a frequency selective channel and is suitable for multi-carrier transmissions with quadrature amplitude modulations is proposed.
Patent
Multilevel channel coding in ADSL
TL;DR: In this article, various techniques for multilevel channel coding are discussed for a given binary word comprising a plurality of bits, the least significant bit may be encoded by a boosted coding technique, such as turbo channel coding or low density parity check (LDPC) channel coding.
Journal ArticleDOI
Combined equalization and coding for high-density saturation recording channels
W.L. Abbott,John M. Cioffi +1 more
TL;DR: Combined equalization and coding approaches which significantly outperform previous techniques are presented for the binary Lorentzian channel with additive Gaussian noise.
Journal ArticleDOI
Optimization of trellis coded TFM via matched codes
TL;DR: The matched coding technique is applied to coded tamed frequency modulation (TFM) schemes and a formal procedure is developed to find the best combination of a code and a modulation.
References
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