基于联合编码调制的调光控制方案实现

针对可见光通信系统中闪烁抑制与调光控制功能的实现，提出了一种采用联合编码调制进行调光控制的方法。该方法利用脉冲宽度调制(PWM)匹配数据帧内与帧间的占空比，同时结合游程长度受限编码(RLL)实现闪烁抑制；通过分别采用多脉冲位置调制(MPPM)和重叠脉冲位置调制(OPPM)实现光强调节，以满足功率效率或频谱效率需求。理论分析表明，与典型的可变脉冲位置调制(VPPM)相比，占空比为0.9的MPPM的归一化功率可节省2.24dB，而占空比为0.5的OPPM的频谱利用率高出0.8bps/Hz，即OPPM具有较高的频谱效率。此外，基于FPGA平台开发实现提出2种调制方案，实验结果验证了联合调制调光方案可以在保证数据有效传输的条件下抑制光源闪烁并可进行高精度的调光控制。

Implementation of dimming control scheme based on joint coding and modulation

To realize the function of flicker mitigation and dimming control in visible light communication system, a scheme of dimming control using joint coding modulation was proposed. In the scheme, the pulse width modulation (PWM) and the run length limited code (RLL) were adopted to match the duty cycle between the intra-frame and the inter-frame as well as to achieve the flicker mitigation respectively, and also the multi-pulse position modulation (MPPM) and the overlapped pulse position modulation (OPPM) were utilized to achieve light intensity adjustment for the purpose of improving the power efficiency or spectral efficiency. Theoretical analysis demonstrates that compared with a typical variable pulse position modulation (VPPM), the normalized power of the MPPM with a duty ratio of 0.9 can save 2.24 dB, and the spectrum utilization of the OPPM with a duty ratio of 0.5 is higher than 0.8 bps/Hz, which means OPPM has a higher spectrum efficiency. In addition, two modulation schemes based on the FPGA platform were implemented. The experimental results verify that the joint modulation dimming scheme can support the light source flicker mitigation and high-precision dimming control under the condition of ensuring the effective data transmission.