| 张俊,张剑.可见光通信光叠加正交频分复用技术研究[J].光电子激光,2015,26(6):1087~1093 |
| 可见光通信光叠加正交频分复用技术研究 |
| Research on optical superposition modulation orthogonal frequency division m ultiplexing technique in visible light communication |
| 投稿时间：2015-02-27 |
| DOI： |
| 中文关键词: 发光二极管(LED) 非线性 限幅失真 调制深度 有效信噪比(SNR ) 最优直流偏置 |
| 英文关键词:light emitting diode (LED) nonlinearity clipping distortion modulation depth effective signal to noise ratio (SNR) optimal DC bi as |
| 基金项目:国家自然科学基金(61271253)和国家“863计划”(2013AA013603)资助项目 (解放军信息工程大学,河南 郑州 450001) |
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| 中文摘要: |
| 针对可见光通信(VLC)正交频分复用(OFDM)系统 发光二极管(LED)动态范围窄、非线性和限幅失真严重等问题,利用光 源具有多个灯芯的特点,将OFDM频带划分为多个子带,每个子带内数据通过傅里叶反变换(IFFT)产生一路独立信号输入LED 灯芯,所有LED灯芯发出的光信号在空间上叠加形成光叠加OFDM(OSM-OFDM) 信号。在相同直流偏置情况下, OSM-OFDM系统每一路信号的调制深度较低,能够有效地避免LED非线性和限幅影响,特别是 在输入信号功率较大时,系统 误码率(BER)降低了至少1个数量级。根据有效信噪比(SNR) 最大原则能够得到OSM-OFDM系统最优直流偏置,而且在系统设计时可以根据 系统有效信噪比公式选择合适的LED灯芯数。实验表明,OSM-OFDM系统BER 性能要比直流偏置光OFDM(DCO-OFDM)系统提升了1个数量 级。 |
| 英文摘要: |
| The light emitting diode (LED) has limited dyna mic range,significant nonlinearity and clipping distortion in visible light communication orthogonal frequency division multiplexing (OFDM) system.By using the characteristics of light source which has many wicks,the bandwidth of OFDM is divided into several sub-bands.Data from each sub-band is used to generate a single signal by the inverse fast Fourier transform (IFFT) and the single signal is input into eac h LED wick.Then the optical superposition modulation OFDM (OSM-OFDM) signal is formed by the superposition of optical signals from all th e LED wicks.The modulation index of every single signal is low with the same DC bias in OSM-OFDM system.So it effectively avoids the n onlinearity and clipping distortion caused by LED.In particular,the system bit error rate (BER) performance d ecreases at least by an order of magnitud e with high input power.The optimal DC bias of OSM-OFDM system is achieved by the principle of maximum effective signal to noi se ratio (SNR).And the suitable number of LED wicks is chosen based on the equation of effective SNR when a real system is designed.E xperimental results show that the BER performance of OSM-OFDM system has improved an order of magnitude than the direct current o ptical orthogonal frequency division multiplexing (DCO-OFDM) system. |
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