Geometric Constellation Shaping for Wireless Optical Intensity Channels: An Information-Theoretic Approach

A simple geometric shaping method is proposed for optical wireless communication systems based on intensity modulation and direct detection (IM/DD) from an information-theoretic perspective. Constellations consisting of equiprobable levels with exponential-like distribution are obtained, which posse...

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Bibliographic Details
Published in:IEEE communications letters 2024-12, p.1-1
Main Authors: Zhou, Suhua, Li, Tianqi, Fang, Zhaoxi, Zhou, Jing, Zhang, Wenyi
Format: Article
Language:English
Subjects:
Channel capacity
constellation shaping
intensity modulation
optical wireless communications
Online Access:Get full text
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Summary:A simple geometric shaping method is proposed for optical wireless communication systems based on intensity modulation and direct detection (IM/DD) from an information-theoretic perspective. Constellations consisting of equiprobable levels with exponential-like distribution are obtained, which possesses asymptotic optimality in the sense that the high-SNR capacity of average-intensity constrained optical intensity channel can be approached by such constellations with increasing size. All 2 b levels ( b ϵ N) of the obtained constellation can be represented by a basic level and b + 2 bits, thereby reducing the required resolution of the digital-to-analog converter (DAC) without affecting the asymptotic optimality. Achievable information rate evaluations verify the asymptotic optimality. As an example, error performance results of a simple 16-level LDPC coded modulation scheme show that a shaping gain of 0.65 dB can be obtained by applying the proposed constellation design. This method can also be applied to more specific IM/DD channel models, since it only requires a near-optimal continuous input distribution.
ISSN:1089-7798
DOI:10.1109/LCOMM.2024.3511129