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arXiv 2406.01031cs.ITmath.IT
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无线光强度信道的几何星座成形:一种信息论方法

Geometric constellation shaping for wireless optical intensity channels: An information-theoretic approach

Suhua Zhou, Tianqi Li, Zhaoxi Fang, Jing Zhou, Wenyi Zhang

AI总结:

针对 IM/DD 光无线强度信道,提出由类指数等概率电平构成的几何星座成形方法,证明其高 SNR 渐近最优性,并通过 16 电平 LDPC 方案获得 0.65 dB 成形增益。

摘要:

本文从信息论角度出发,为基于强度调制与直接检测(IM/DD)的光无线通信系统提出了一种简单的几何成形方法。所得星座由等概率且呈类指数分布的电平组成,并具有渐近最优性:随着星座规模增大,此类星座能够逼近平均强度受限时光强度信道的高信噪比容量。所得星座的全部 $2^b$ 个电平($b\in\mathbb N$)均可由一个基础电平和 $b+2$ 个比特表示,从而在不影响渐近最优性的前提下降低对数模转换器(DAC)分辨率的要求。可达信息速率评估验证了这种渐近最优性。作为示例,一个简单的 $16$ 电平 LDPC 编码调制方案的误码性能结果表明,采用所提出的星座设计可获得 $0.65$ dB 的成形增益。该方法也可应用于更具体的 IM/DD 信道模型,因为它只需要一个近最优的连续输入分布。

英文摘要:

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 ($b\in\mathbb N$) 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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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