基于U-OFDM的室内可见光通信系统调光控制方法

作为未来短距离无线通信有效可选方案的可见光通信,照明控制是其面临的主要挑战之一.在分析了采用连续电流调节(CCR)和脉冲宽度调制(PWM)两种调光控制技术的OFDM系统工作原理的基础上,提出了一种新的室内可见光高速通信调光控制系统设计方案.该方案将照明应用中的两种调光技术引入到功率效率高、误码性能好的单极性光OFDM(Unipolar OFDM)系统中,在提供良好传输性能的同时实现了照明信号的连续调节和线性调节功能.仿真实验表明,提出的方案调光控制性能与非对称消波光OFDM (ACO-OFDM)系统接近,而误码性能则优于后者,即U-OFDM调光控制系统可在不牺牲照明质量的同时获得更好的误码性能.

A Scheme of U-OFDM Based Dimming Control for Indoor Visible Light Communication Systems

Dimming control is one of the main challenges for Visible Light Communication (VLC) which is a promising candidate for future short distance wireless communications.To this end,the principles of two dimming control methods,i.e.continuous current reduction (CCR) and pulse width modulation (PWM),employed in optical OFDM system were discussed,and also a new dimming control scheme was proposed in this paper.CCR and PWM were applied in unipolar OFDM (U-OFDM) system,which can achieve better performance in terms of both power efficiency and bit error rate.This scheme can make sure that lighting signal will be adjusted continuously and linearly while maintaining a reliable communication link.Simulation results demonstrate that dimming control performance of this new scheme is equally good as asymmetrically clipped optical OFDM (ACO-OFDM),and the bit error rate is better than the latter.The U-OFDM system using dimming control can obtain better error performance in the mean time without sacrificing illumination quality.