Soft Demapping of Spherical Codes from Cartesian Powers of PAM Constellations
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| Pubblicato in: | arXiv.org (Nov 20, 2024), p. n/a |
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| Autore principale: | |
| Altri autori: | , , |
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Cornell University Library, arXiv.org
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| Accesso online: | Citation/Abstract Full text outside of ProQuest |
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| 001 | 3034837032 | ||
| 003 | UK-CbPIL | ||
| 022 | |a 2331-8422 | ||
| 035 | |a 3034837032 | ||
| 045 | 0 | |b d20241120 | |
| 100 | 1 | |a Reza Rafie Borujeny | |
| 245 | 1 | |a Soft Demapping of Spherical Codes from Cartesian Powers of PAM Constellations | |
| 260 | |b Cornell University Library, arXiv.org |c Nov 20, 2024 | ||
| 513 | |a Working Paper | ||
| 520 | 3 | |a For applications in concatenated coding for optical communications systems, we examine soft-demapping of short spherical codes constructed as constant-energy shells of the Cartesian power of pulse amplitude modulation constellations. These are unions of permutation codes having the same average power. We construct a list decoder for permutation codes by adapting Murty's algorithm, which is then used to determine mutual information curves for these permutation codes. In the process, we discover a straightforward expression for determining the likelihood of large subcodes of permutation codes called orbits. We introduce a simple process, called orbit demapping, that allows us to extract soft information from noisy permutation codewords. In a sample communication system with probabilistic amplitude shaping protected by a standard low-density parity-check code that employs short permutation codes, we demonstrate that orbit demapping provides a gain of about 0.3 dB in signal-to-noise ratio compared to the traditional symbol-by-symbol demapping. By using spherical codes composed of unions of permutation codes, we can increase the input entropy compared to using permutation codes alone. In one scheme, we consider a union of a small number of permutation codes. In this case, orbit demapping provides about 0.2 dB gain compared to the traditional method. In another scheme, we use all possible permutations to form a spherical code that exhibits a computationally feasible trellis representation. The soft information obtained using the BCJR algorithm outperforms the traditional symbol-by-symbol method by 0.1 dB. Using the spherical codes containing all possible permutation codes of the same average power and the BCJR algorithm, a gain of 0.5 dB is observed. Comparison of the achievable information rates of bit-metric decoding verifies the observed gains. | |
| 653 | |a Noise levels | ||
| 653 | |a Algorithms | ||
| 653 | |a Communications systems | ||
| 653 | |a Unions | ||
| 653 | |a Codes | ||
| 653 | |a Symbols | ||
| 653 | |a Permutations | ||
| 653 | |a Decoding | ||
| 653 | |a Pulse amplitude modulation | ||
| 653 | |a Error correcting codes | ||
| 653 | |a Optical communication | ||
| 653 | |a Cartesian coordinates | ||
| 653 | |a Signal to noise ratio | ||
| 700 | 1 | |a Rumsey, Susanna E | |
| 700 | 1 | |a Draper, Stark C | |
| 700 | 1 | |a Kschischang, Frank R | |
| 773 | 0 | |t arXiv.org |g (Nov 20, 2024), p. n/a | |
| 786 | 0 | |d ProQuest |t Engineering Database | |
| 856 | 4 | 1 | |3 Citation/Abstract |u https://www.proquest.com/docview/3034837032/abstract/embedded/7BTGNMKEMPT1V9Z2?source=fedsrch |
| 856 | 4 | 0 | |3 Full text outside of ProQuest |u http://arxiv.org/abs/2404.04776 |