北京邮电大学学报

  • EI核心期刊

北京邮电大学学报 ›› 2024, Vol. 47 ›› Issue (2): 137-142.

• 研究报告 • 上一篇    

基于IM-DD的无线光信道容量分析

蒋立荣,李龙光   

  1. 华东师范大学
  • 收稿日期:2023-02-22 修回日期:2023-04-18 出版日期:2024-04-28 发布日期:2024-01-24
  • 通讯作者: 李龙光 E-mail:lgli@cee.ecnu.edu.cn

On the Capacity of Optical Wireless Channels Based on IM-DD

  • Received:2023-02-22 Revised:2023-04-18 Online:2024-04-28 Published:2024-01-24

摘要: 无线光信道通常采用强度调制-直接检测(IM-DD)方式传输信息。然而,在基于 IM-DD 的无线光信道容量分析中,现有信道容量相关结果在有限信噪比范围内存在估计精确度较低的问题。为了解决这一问题, 考虑了受到平均光强约束的无线光信道中的非负输入信号。通过利用信道容量的双重表达式,并选择有效的辅助输出分布, 推导出了新的信道容量上界。同时,结合离散分布信息熵的性质和最大熵原理,推导出了新的信道容量下界。仿真结果表明,在中、高信噪比范围内,得到了对信道容量上界的精准估计,且高信噪比下渐近最优。在中、低信噪比范围内,得到了对信道容量下界的精准估计。

关键词: 无线光通信, 信道容量, 强度调制-直接检测, 信息熵

Abstract: Most of current optical wireless communication (OWC) systems use the intensity modulation-direct detection (IM-DD) method to convey information. Existing results on the capacity analysis of OWC channels based on IM-DD cannot give good approximations to the capacity at finite SNR. In the light of this, with duality capacity expression, by choosing an auxiliary output distribution, a new capacity upper bound on the capacity is derived. Compared with existing capacity bounds, numerical results show that the upper bound gives better approximation to the capacity at moderate and high SNR, and is asymptotically tight at high SNR. Also, by using the properties of discrete input entropy, combined with maximum entropy argument, a new capacity lower bound is derived. Numerical results show that the lower bound significantly improves the performance of capacity approximation at low and moderate SNR.

Key words: optical wireless communication, channel capacity, intensity modulation-direct detection (IM-DD), information entropy

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