Hartley变换OFDM调制的可见光通信研究

Research on OFDM System Based on Hartley Transform in Visible Light Communication

针对正交频分复用(OFDM)可见光通信系统中存在高峰均功率比的问题,将预编码与迭代限幅滤波技术相结合应用于Hartley变换OFDM调制的可见光通信系统中,并对传统的采用FFT/IFFT限幅滤波的OFDM系统进行改进。根据建立的FHT的可见光OFDM系统模型,分别比较了不同方案下系统的频谱利用率、PAPR和误码率等性能,并分析了Hadamard矩阵和离散余弦变换预编码对PAPR的抑制作用以及FFT/IFFT、DCT/IDCT和FHT/IFHT三种不同变换方案的滤波性能。结果表明:FHT的可见光OFDM系统比FFT的OFDM系统的计算复杂度低、频谱利用率高;DCT预编码技术在克服系统PAPR及提升系统误码性能上更具优势;FHT/IFHT迭代限幅滤波的误码性能优于FFT/IFFT和DCT/IDCT。

Aiming at the problem that high peak-to-average power ratio(PAPR)of orthogonal frequency division multiplexing(OFDM)system in visible light communication,combined precoding and iterative clipping and filtering were applied to OFDM system based on Hartley transform,and the performance of OFDM system based on conventional Fourier transform with iterative clipping and filtering using FFT/IFFT transform was improved in this paper.According to the established system model,the spectrum utilization,PAPR and BER of different schemes were compared.The PAPR suppression effect of Hadamard matrix and discrete cosine transform precoding were analyzed.In addition,BER of filtering transformations such as FFT/IFFT,DCT/IDCT and FHT/IFHT were compared.The results show that compared with the OFDM system based on FFT,there are advantages of lower algorithm complexity and higher spectral efficiency for the OFDM system based on FHT.There are more advantages for DCT precoding technology in suppressing PAPR and improving the BER performance,and the optimal BER performance can be achieved by using iterative clipping and filtering with FHT/IFHT.