Designing Nonlinear Turbo Codes with a Target Ones Density
Abstract
Certain binary asymmetric channels, such as Z-channels in which one of the two crossover probabilities is zero, demand optimal ones densities different from 50%. Some broadcast channels, such as broadcast binary symmetric channels (BBSC) where each component channel is a binary symmetric channel, also require a non-uniform input distribution due to the superposition coding scheme, which is known to achieve the boundary of capacity region. This paper presents a systematic technique for designing nonlinear turbo codes that are able to support ones densities different from 50%. To demonstrate the effectiveness of our design technique, we design and simulate nonlinear turbo codes for the Z-channel and the BBSC. The best nonlinear turbo code is less than 0.02 bits from capacity.
Keywords
Cite
@article{arxiv.1107.1563,
title = {Designing Nonlinear Turbo Codes with a Target Ones Density},
author = {Jiadong Wang and Thomas Courtade and Tsung-Yi Chen and Bike Xie and Richard Wesel},
journal= {arXiv preprint arXiv:1107.1563},
year = {2011}
}