降低可见光OFDM系统峰均比的新方法

A new method to reduce the PAPR of OFDM signal in visible light communication system

摘要:

可见光正交频分复用(OFDM)系统的一个主要缺点是系统的峰均比(PAPR)较高，会引起信号失真。为了降低可见光OFDM通信系统的峰均比，本文将选择性映射(SLM)方法引入可见光通信系统中，并将其进行适当的改进，使之满足可见光通信信号必须为正的实信号的要求。提出将离散傅里叶变换展开(DFTS)与SLM相结合(DFT-S-SLM)的方法来进一步降低可见光OFDM系统的峰均比。仿真结果表明，与原信号、仅采用DFT展开或者SLM方法相比，在增加一定的系统复杂度的情况下，DFT-S-SLM方法具有更好的峰均比性能。

Abstract:

High Peak to Average Power Ratio(PAPR) is one of the major disadvantages of the Visible Light Communication(VLC) Orthogonal Frequency Division Multiplexing(OFDM) system as it can cause signal distortion. A Selective Mapping(SLM) method is introduced in order to reduce the PAPR of OFDM signal in VLC system, which is modified to suit the demand that the signals must be positive and real. A method combining the Discrete-Fourier-Transform Spread(DFTS) and SLM is proposed to reduce the PAPR in VLC OFDM system further. The simulation results show that，comparing with the original signal，DFTS or SLM method used alone, the DFT-S-SLM method has the best PAPR performance at the cost of a certain increase of system complexity.