考虑发射时隙的可见光通信差分脉冲位置调制

Differential pulse position modulation of visible light communication considering transmission time slots

在可见光通信系统中,若脉冲信号出现问题,会导致信号失真和码间干扰,严重影响光通信系统的通信质量。传统的差分脉冲位置调制方法没有充分考虑发射时隙和信道特性对脉冲位置的影响,从而导致解调时的误差和性能下降。提出考虑发射时隙的可见光通信差分脉冲位置调制方法。基于可见光通信模型,选择链路中漫反射传输类型,获取通信系统的脉冲信号响应关系。基于响应关系确定脉冲延迟影响因素,对标链路中脉冲延迟与发射时隙的频率关系,参考上下边界理论,计算差分脉冲位置调制边界范围。根据调制边界,考虑信道脉冲发射时隙,确定差分脉冲位置调制方程,实现可见光通信差分脉冲位置调制方法设计。实验结果表明:以可见光通信系统中不同传输路径为测试对象,当路径出现脉冲延迟时,所研究方法可以保证较低的带宽-功率指数,稳定地实现通信系统的脉冲调制,以此降低路径中的传输误码率。

In visible light communication systems,if there is a problem with the pulse signal,it can cause signal distortion and inter symbol interference,seriously affecting the communication quality of the optical communication system.The traditional differential pulse position modulation method does not fully consider the impact of transmission time slots and channel characteristics on pulse position,resulting in errors and performance degradation during demodulation.Therefore,a research method for visible light communication differential pulse position modulation considering transmission time slots is proposed.Based on the visible light communication model,select the diffuse reflection transmission type in the link to obtain the pulse signal response relationship of the communication system.Based on the response relationship,determine the influencing factors of pulse delay,benchmark the frequency relationship between pulse delay and transmission time slot in the link,refer to the upper and lower boundary theory,and calculate the boundary range of differential pulse position modulation.Based on the modulation boundary and considering the channel pulse transmission time slot,determine the differential pulse position modulation equation,and design the differential pulse position modulation method for visible light communication.The experimental results show that when the pulse delay occurs in different transmission paths in the visible light communication system,the proposed method can guarantee a lower bandwidth power index,stably realize the pulse modulation of the communication system,and thus reduce the transmission bit error rate in the path.