指数Weibull信道下FTN无线光通信盲均衡优化算法  

Blind Equalization Optimization Algorithm for FTN Optical Wireless Communication over Exponential Weibull Channel

作　　者：曹明华[1] 孙沁雪 姚瑞芳 张悦 张霞[2,3] 贾科军[1] 王惠琴[1] Cao Minghua;Sun Qinxue;Yao Ruifang;Zhang Yue;Zhang Xia;Jia Kejun;Wang Huiqin(School of Computer and Communication,Lanzhou University of Technology,Lanzhou 730050,Gansu,China;School of Physics Science and Information Engineering,Liaocheng University,Liaocheng 252000,Shandong,China;Shandong Provincial Key Laboratory of Optical Communications Science and Technology,Liaocheng University,Liaocheng 252000,Shandong,China)

机构地区：[1]兰州理工大学计算机与通信学院,甘肃兰州730050 [2]聊城大学物理科学与信息工程学院,山东聊城252000 [3]聊城大学山东省光通信科学与技术重点实验室,山东聊城252000

出　　处：《光学学报》2024年第12期187-196,共10页Acta Optica Sinica

基　　金：国家自然科学基金(62265010,62261033);山东省自然科学基金(ZR2022MF284)。

摘　　要：针对指数Weibull信道模型下大气湍流效应导致的光信号相位噪声、信号畸变和超奈奎斯特(FTN)技术引入的码间干扰(ISI)问题,提出一种判决反馈恒模均衡两步(TS-DFE-CMA)优化算法。该算法将判决反馈思想引入恒模均衡(CMA)来提升系统抵抗各类干扰的能力,同时采用两步(TS)优化思想更新步长系数以控制计算复杂度并提高系统均衡性能。将所提算法与恒模均衡维特比-维特比相位估计(CMA-VVPE)、TS-CMA-VVPE和DFE-CMA 3种算法进行性能对比,结果表明,所提算法的误码率(BER)最低,TS-CMA-VVPE次之。引入FTN的ISI后,在弱湍流信道和FTN加速因子为0.9的条件下,与TS-CMA-VVPE算法相比,所提算法的误码性能提升了16.01%,误差矢量幅度(EVM)性能提升了6.49%。Objective The commercialization of the fifth-generation(5G)mobile communication industry has escalated the demand for efficient and cost-effective application technologies.The faster-than-Nyquist(FTN)transmission technology in coherent optical wireless communication systems has caught significant attention due to its high signal transmission rate and channel capacity enhancement capabilities.However,the receiving terminal of the coherent optical system exhibits a high level of complexity,with performance significantly influenced by turbulence-induced phase noise and inter-symbol interference(ISI)introduced by FTN.Therefore,it is imperative to conduct studies on low-complexity optimization algorithms to address these challenges.In this regard,a blind equalization scheme for FTN quadrature phase shift keying(QPSK)coherent optical wireless communication signals under exponential Weibull channels has been devised.This scheme optimizes the signal processing algorithm at the receiving end to minimize complexity costs.A novel algorithm named TS-DFE-CMA has been proposed to integrate decision-feedback equalization(DFE)into a constant modulus algorithm(CMA),thereby enhancing system resilience against various disturbances.Additionally,employing a two-step(TS)approach enhances step coefficient selection and transformation methods to control computational complexity,with improved system performance.Simulation results demonstrate that the proposed algorithm mitigates signal distortion caused by FTN ISI and turbulence effects.Methods The transmitted signal undergoes QPSK mapping,FTN shaping filtering,and digital-to-analogue conversion at the transmitter.It is then split into two orthogonal signals of I and Q,which are transmitted by an optical antenna into a turbulent channel following an exponential Weibull distribution model.The received optical signal is subjected to zerophase coherent detection using a 90°mixer,followed by analogue-to-digital conversion.Subsequently,signal processing techniques such as equalization and ph

关 键 词：大气光通信 超奈奎斯特 指数Weibull信道 盲均衡算法 

分 类 号：TN929.12[电子电信—通信与信息系统]