TY - GEN
T1 - Geometric shaping
T2 - 2018 IEEE Information Theory Workshop, ITW 2018
AU - Boutros, Joseph J.
AU - Erez, Uri
AU - Van Wonterghem, Johannes
AU - Shamir, Gil I.
AU - Zémor, Gilles
N1 - Publisher Copyright:
© 2018 IEEE Information Theory Workshop, ITW 2018. All rights reserved.
PY - 2018/7/2
Y1 - 2018/7/2
N2 - Constellation shaping is necessary to approach channel capacity for information rates above 1 bit/dim. Probabilistic shaping shows a small gap to capacity, however a complex distribution matcher is required to modify the source distribution. Spherical shaping of lattice constellations also reduces the gap to capacity, but practical Voronoi shaping is feasible in small dimensions only. In this paper, our codebook is a real geometrically nonuniform Gaussian-like constellation. We prove that this discrete codebook achieves channel capacity when the number of points goes to infinity. Then we build a special mapping to interface between non-binary low-density codes and the codebook, allowing the code alphabet size to be equal to the square root of the codebook size. Excellent performance is shown with fast-encoding and practical iterative probabilistic decoding, e.g. 0.7 dB gap to capacity at 6 bits/s/Hz with a code defined over the ring Z/8Z.
AB - Constellation shaping is necessary to approach channel capacity for information rates above 1 bit/dim. Probabilistic shaping shows a small gap to capacity, however a complex distribution matcher is required to modify the source distribution. Spherical shaping of lattice constellations also reduces the gap to capacity, but practical Voronoi shaping is feasible in small dimensions only. In this paper, our codebook is a real geometrically nonuniform Gaussian-like constellation. We prove that this discrete codebook achieves channel capacity when the number of points goes to infinity. Then we build a special mapping to interface between non-binary low-density codes and the codebook, allowing the code alphabet size to be equal to the square root of the codebook size. Excellent performance is shown with fast-encoding and practical iterative probabilistic decoding, e.g. 0.7 dB gap to capacity at 6 bits/s/Hz with a code defined over the ring Z/8Z.
UR - http://www.scopus.com/inward/record.url?scp=85062102499&partnerID=8YFLogxK
U2 - 10.1109/ITW.2018.8613506
DO - 10.1109/ITW.2018.8613506
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AN - SCOPUS:85062102499
T3 - 2018 IEEE Information Theory Workshop, ITW 2018
BT - 2018 IEEE Information Theory Workshop, ITW 2018
PB - Institute of Electrical and Electronics Engineers Inc.
Y2 - 25 November 2018 through 29 November 2018
ER -