基于LWT的可见光DCO-OFDM系统  

Visible DCO-OFDM System Based on LWT

作　　者：赵黎[1] 董航航 张峰[1] ZHAO Li;DONG Hanghang;ZHANG Feng(School of Electronic Information Engineering,Xi!an Technological University,Xi'an 710021,China)

机构地区：[1]西安工业大学电子信息工程学院,西安710021

出　　处：《光子学报》2021年第5期121-129,共9页Acta Photonica Sinica

基　　金：国家自然科学基金项目(No.61271362);陕西省科技厅一般项目-工业领域(No.2020GY-054);西安市科技计划项目(No.2020KJRC0040)。

摘　　要：为了解决传统正交频分复用技术峰均比过高、复值型信号结构无法直接应用于强度调制直接检测系统等问题,将提升小波变换(LWT)应用于正交频分复用(OFDM)中,选择正交小波基作为子载波,通过对信号的预测与更新,将信号的高低频分离,并结合可见光通信(VLC)多次反射信道模型,建立了DCO-LWT-OFDM系统模型,推导了LWT-OFDM信号迭代分解与更新重构公式,对其性能分别进行了仿真分析与实验验证。模拟仿真实验表明,在4 m×4 m×3 m室内空间中,当系统误码率为10^(-4)时,DCO-LWT-OFDM系统较DCO-FFT-OFDM系统的性能大约提高了5 dB,综合效率提高了70%,当系统峰均比为10dB时,DCO-FFT-OFDM系统的互补累积分布函数值接近10^(-1),DCO-LWTOFDM系统的互补累积分布函数值为0。实验验证中,选择1 W LED灯珠在光学导轨上搭建点到点DCO-LWT-OFDM VLC系统,传输距离为20 cm,系统调制误差率为11.4 dB,可靠性可达10^(-4)。本文研究为提高可见光通信的传输速率,降低系统误码率,抑制系统峰均比提供了一种有效途径。In order to solve the problems of high peak-to-average ratio of traditional orthogonal frequency division multiplexing technology,complex-valued signal structure cannot be directly applied to intensity modulation direct detection system,Lifting Wavelet Transform(LWT)is applied to Orthogonal Frequency Division Multiplexing(OFDM).The orthogonal wavelet basis is selected as the subcarrier.By predicting and updating the signal,the high and low frequencies of the signal are separated.Combined with the multiple reflection channel model of Visible Light Communication(VLC),the DCO-LWT-OFDM system model was established,and the iterative decomposition and renewal reconstruction formulas of LWT-OFDM signals were deduced.The performance of the DCO-LWT-OFDM system was simulated and verified by experiments.Simulation results show that in a 4 m×4 m×3 m indoor space,when the bit error rate of the system is 10^(-4),the performance of the DCO-LWT-OFDM system is about 5 dB higher than that of the DCO-FFT-OFDM system,and the overall efficiency is improved by 70%.When the system peak-to-average ratio is 10 dB,the value of complementary cumulative distribution function of DCO-FFT-OFDM system is close to 10^(-1),and the value of complementary cumulative distribution function of DCO-LWT-OFDM system is 0.In the experimental verification,1 W LED lamp beads were selected to build the point-to-point DCO-LWT-OFDM VLC system on the optical guide,the transmission distance was 20 cm,the system modulation error rate was 11.4 dB,and the reliability could reach 10^(-4).This paper provides an effective way to improve the transmission rate of visible light communication,reduce the bit error rate and restrain the system PAPR.

关 键 词：可见光通信 正交频分复用 提升小波变换 误码率 通信效率 

分 类 号：TN929.1[电子电信—通信与信息系统]