可见光通信光正交频分复用系统符号分解技术抑制LED非线性失真研究  

LED Nonlinearity Mitigation for Visible Light Communication Optical-Orthogonal Frequency Division Multiplexing System with Symbol Decomposing Techniques

作　　者：贾科军[1] 杨博然 陆皓 郝莉[2] Jia Kejun;Yang Boran;Lu Hao;Hao Li(School of Computer and Communication,Lanzhou University of Technology,Lanzhou,Gansu 730050,China;School of Information Science and Technology,Southwest Jiaotong University,Chengdu,Sichuan 610031,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]西南交通大学信息科学与技术学院,四川成都610031

出　　处：《中国激光》2020年第4期226-234,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(61461026,61562058,61841107);甘肃省自然科学基金(18JR3RA153)。

摘　　要：传统重复信号限幅(ISC)技术可以减小非线性LED光正交频分复用(O-OFDM)系统的非线性限幅噪声影响。但ISC系统需要多个LED同时发光,同步和硬件实现复杂,并且误码率(BER)随着信道增益差异的增大而变大。基于此,提出基于单个LED的O-OFDM符号分解串行传输系统,对O-OFDM符号进行限幅分解,然后串行组帧,最后输入到单个LED中。推导了系统理论信噪比表达式,并建立了蒙特卡罗误码率和误差矢量幅度(EVM)仿真模型。结果表明,随着符号分解次数增大,EVM和BER性能显著变好,但通信速率略有下降,并且直流偏置会影响EVM和BER性能。本系统实现简单,避免了信道增益差异引起的BER变差问题。Traditional iterative signal clipping(ISC)techniques can reduce the effect of nonlinear clipping noise in nonlinear LED optical-orthogonal frequency division multiplexing(O-OFDM)systems.However,the ISC system requires multiple LEDs to emit light at the same time,which is complicated in synchronization and hardware applications,as the bit error rate(BER)increases with the channel gain difference.An O-OFDM symbol decomposing serial transmission system based on single LED is proposed in this study.The O-OFDM symbol is decomposed by amplitude clipping,followed by serial framing,and it is finally input to single LED.The expression of the system theoretical signal-to-noise ratio is derived and the simulation models using the Monte Carlo bit error rate and the error vector magnitude(EVM)are built.Results demonstrate that the performance of EVM and BER enhance significantly as the number of symbols decomposing increases;however,the communication rate slightly decreases,and the direct current biases will affect the performance of EVM and BER.Furthermore,the proposed system is simple to implement and avoids the problem of BER degradation caused by the channel gain difference.

关 键 词：光通信 光正交频分复用 重复信号限幅 符号分解 限幅噪声 误差矢量幅度 

分 类 号：TN929.12[电子电信—通信与信息系统]