无线光通信中LACO-OFDM的非迭代检测接收方法  

Noniterative Detection Receiving Method for LACO-OFDM in Wireless Optical Communications

作　　者：刘晓爽 李建锋 任亚浩 黄治同[2] Liu Xiaoshuang;Li Jianfeng;Ren Yahao;Huang Zhitong(Information Technology College,Hebei University of Economics and Business,Shijiazhuang 050061,Hebei,China;Stats Key Laboratory of Information Photonics and Optical Communications,Beijing University of Posts and Telecommunications,Beijing 100876,China)

机构地区：[1]河北经贸大学信息技术学院,河北石家庄050061 [2]北京邮电大学信息光子学与光通信国家重点实验室,北京100876

出　　处：《中国激光》2022年第11期109-116,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(61801165);河北省“三三三人才工程”资助(A202101015);河北省高等学校科学技术研究项目(ZD2020163,ZD2021044);国家新工科研究与实践项目(E-JSJRJ20201310)。

摘　　要：针对无线光通信(WOC)的分层非对称切除正交频分复用(LACO-OFDM)系统存在非线性噪声干扰的问题,提出一种非迭代检测接收方法。该方法在加性高斯白噪声(AWGN)信道下,会有一定的性能损失,但是在非线性信道下,非迭代检测接收机不会将下层ACO-OFDM的非线性噪声传播到上层信号中,从而可以得到更好的误码率(BER)性能。结果表明:与传统迭代检测方法相比,非迭代检测接收机在非线性限幅信道下,可获得1 dB~3 dB的信噪比增益;该方法可有效减弱非线性噪声的干扰,随着非线性噪声的增强,可获得更高的增益。Objective The orthogonal frequency division multiplexing(OFDM)is currently widely studied for wireless optical communications.Asymmetrically clipped optical OFDM(ACO-OFDM)is a unipolar technique with high energy efficiency,but only odd subcarriers carry data,resulting in low spectral efficiency.Layered ACO-OFDM(LACO-OFDM)is proposed to improve the spectral efficiency of ACO-OFDM.Among many unipolar OFDM technologies,LACO-OFDM has the highest signal-to-noise ratio(SNR)gain at the same spectral efficiency.The maximum likelihood detection of the current layer signal must be conducted in the frequency domain in the conventional LACO-OFDM receiver.The detection result is then fed back to the received signal,and the upper ACO-OFDM is restored,which is called iterative detection.However,the nonlinear noise in the iterative detection receiver in nonlinear channels can be transmitted from the lower to the upper layer of LACO-OFDM.The performance of the LACO-OFDM system deteriorates due to iterative detection.A noniterative detection receiving method is proposed in this paper to mitigate the nonlinearity for LACO-OFDM.Methods The maximum likelihood detection in the frequency domain of the proposed receiver is removed,which is used in the conventional iterative detection receiver.First,fast Fourier transform(FFT)is performed for the received LACO-OFDM signal(Fig.1).Then,Layer l of LACO-OFDM is directly demodulated.The inverse fast Fourier transform(IFFT),asymmetric clipping,and FFT are performed for Layer l to restore Layer l+1.Layer l can then be removed for the received LACO-OFDM signal to obtain the Layer l+1.The noniterative detection receiver has some performance loss in the additive white Gaussian noise channel.However,this receiver does not introduce nonlinear noise into the upper ACO-OFDM layer in the nonlinear channel,thus avoiding the nonlinear noise propagation between ACO-OFDM layers.The complexity of the conventional iterative detection receiver depends on FFT and IFFT.Compared with the conventional receiver,on

关 键 词：光通信 无线光通信 分层非对称切除正交频分复用 非迭代检测 非线性信道 

分 类 号：TN929.12[电子电信—通信与信息系统]