可见光通信中自适应DFT-spread-OFDM性能研究

Research on application of adaptive DFT-spread-OFDM in visible light communication

综合考虑可见光通信(VLC)中LED灯调制带宽受限及非线性效应等问题,提出采用离散傅里叶变换(DFT)-spread-OFDM与自适应调制OFDM相结合的一种自适应DFT-spread-OFDM,保证通信可靠性的同时,提高通信速率,通过仿真与实验相结合的方式,研究对比了自适应DFTspread-OFDM与常规DFT-spread-OFDM及常规自适应调制OFDM之间的优劣。仿真和实验结果表明,自适应DFT-spread-OFDM,能够取得良好的综合性能,较常规DFT-spread-OFDM能够实现更高速率的通信,较常规自适应调制OFDM能够取得更佳的峰均功率比的(PAPR,peak-average power radio)性能。

In this paper, considering the limited modulation bandwidth of LED in visible light communica- tion （VLC） and the nonlinear effect of the LED, the technology combining the discrete Fourier transform （DFT）-spread technology with adaptively modulated orthogonal frequency division multiplexing （OFDM） technology, adaptive DFT-spread-OFDM is proposed in this paper for getting both relatively high rate and reliable communication. Through the simulation and the experiment, a comprehensive com- parison is made among adaptive DFT-spread-OFDM scheme, conventional DFT-spread-OFDM scheme and conventional adaptively modulated OFDM scheme. In the simulation, the peak-to-average power ratio （PAPR） complementary cumulative distribution functions （CCDFs） of different system schemes are measured. In the experiment, the bit error ratio （BER） performances of different system schemes are measured for a further comparisolL In addition, the comparisons of the system complexity and the system communication rate are made among different system schemes. The results indicate that adaptive DFT- spread-OFDM scheme can achieve higher rate compared with the conventional DFT-spread-OFDM scheme,and can achieve better PAPR performance compared with conventional adaptively modulated OFDM scheme. It has been verified that the proposed adaptive DFT-spread-OFDM scheme can achieve good comprehensive performance.