可见光多LED并行叠加高速传输功率分配技术研究

利用单个照明灯具内的多个LED灯芯同时发送不同数据，在可见光信道叠加传输后，接收端由单一PD检测汇聚的多路信号，从而实现信息的高速传输。针对叠加传输中LED驱动电压非负特性，提出了基于开关键控OOK调制的接收端检测算法，在此基础上提出了针对LED非线性的信噪比演进和规划的联合功率分配方案。仿真表明该方案在牺牲一定信噪比的条件下使叠加高速通信中LED驱动电压工作在线性范围内并且获得和未规划时相同的误比特率性能；并且和低码率的多灯芯恒定驱动电压方案相比，该方案传输效率更高。 

Power Allocation for Visible Light Communications Multi-LED Parallel Superimposed High Speed Transmission

Multiple LED wicks are used in a single lamp to send disparate data under different driving voltages at the same time. At the receiver, a single photodiode(PD) is used to detect the convergence light intensity signals after superposition transmission in visible light channel. Finally, data can be detected and separated by the divergence of driving voltages. Thus the data rate that is multiple times of a single LED wick can be realized. Due to the nonnegative characteristics of LED driving voltage, the detecting algorithm of the receiver based on on-off keying(OOK) modulation is proposed. Meanwhile, joint power allocation scheme of the Signal to noise ratio(SNR) evolution and programing for the electro-optical conversion nonlinearity of LED are proposed. The simulation shows that sacrifice in SNR could make LED work within the linear range of superposition high-speed communication. And the system could achieve the same bit error rate(BER) performance as the un-programming scheme. Comparing with the low-rate scheme under the constant driving voltage of multiple LED wicks, the proposed scheme is more efficient.