极化码在水下光通信系统中的应用研究

doi:10.19665/j.issn1001-2400.2023.02.004

摘要/Abstract

摘要：

为了验证不同水质条件对水下光通信的影响,采用蒙特卡罗模拟算法模拟了水下光信道的离散冲激响应。在此基础上结合具有抗衰落优点的正交频分复用技术搭建了水下光通信系统,针对收发端已知信道状态信息前提下,采用16正交幅度调制方式,结合蒙特卡罗构造算法完成极化码的构造,译码端使用基于循环冗余校验辅助的串行抵消译码算法,设计并实现了基于正交频分复用技术的水下光通信系统中的极化码编译码方案。通过实验验证了不同水质条件下码长等参数对极化码性能的影响,证明了在高信噪比时,极化码相比同等码长的低密度奇偶校验码在不同水质下具有0.2 dB~0.6 dB左右的性能增益;随着水质环境越差,其渐进性能优势表现得越明显,且不会出现误码平层的问题。极化码的编码结构更加清晰简单,译码复杂度与低密度奇偶校验码相差不大,且在译码中不需要多次迭代。因此相比于其他编码方案,极化码具有较低的编译码复杂度,在水下光通信场景中具有很强的竞争力和应用潜力。

关键词: 水下光通信, 极化码, 蒙特卡罗模拟算法, 正交频分复用, 16正交幅度调制

Abstract:

In order to verify the influence of different water quality conditions on underwater optical communication,the Monte Carlo simulation algorithm is used to simulate the discrete impulse response of the underwater optical channel.Combined with the Orthogonal Frequency Division (OFDM) and strong anti-fading ability,the underwater optical communication system is built based on the OFDM.With known channel state information at the receiver and the transmitter,the 16 Quadrature Amplitude Modulation is used,and the Monte Carlo construction algorithm is applied to construct the polar codes.The CRC-Aided Successive Cancellation List polarization decoding algorithm is used to design the polar codes in OFDM-based underwater optical communication.The influence of parameters such as code length on the performance of polar codes under different water quality conditions is verified by experiments.It is also proved that compared with the low-density parity check(LDPC) codes of the same code length,the polar codes get a performance gain of 0.2dB~0.6dB at the high signal noise ratio.As the water quality environment worsens,its progressive performance becomes more obvious,and there will be no error leveling problem.In addition,the polar codes have a simpler coding structure,the decoding complexity is not much different from that of LDPC codes,and multiple iterations are not required in decoding.Since polar codes have a lower coding and decoding complexity than other coding schemes,polar codes have strong competitiveness and application potential in underwater optical communication scenarios.

Key words: optical communication, polar codes, monte carlo simulation algorithm, orthogonal frequency division multiplexing, 16 quadrature amplitude modulation

中图分类号:

TN911.22

邢莉娟,李卓,王庆港. 极化码在水下光通信系统中的应用研究[J]. 西安电子科技大学学报, 2023, 50(2): 33-41.

XING Lijuan,LI Zhuo,WANG Qinggang. Research on the application of polar codes in the underwater optical communication system[J]. Journal of Xidian University, 2023, 50(2): 33-41.

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参考文献 13

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水质类型	a	b	c
纯净水	0.053	0.003	0.056
沿港水	0.088	0.216	0.305
浑浊水	0.295	1.875	2.170

类型	极化码	LDPC码
调制方式	16-QAM	16-QAM
码长	2 048	2 048
IFFT大小	2 048	2 048
导频数量	256	256
子载波数	1 785	1 785
CP	512	512
码率	1/2	1/2

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