Research And Implementation Of Modulation And Signal Processing Technology In Wireless Optical Communication System

With the increasing popularity of intelligent devices in our daily life, there are more and more wireless communication applications by using wireless communication so that the spectrum resource has been more and more crowded.At the same time, LED, compared with the traditional heating type of light, has a higher luminous intensity and luminous efficient, which ensures that LED is known as a reliable light source selection. Considering protecting environment and saving energy, these characteristics become more prominent.Visible light communication is known as a new method of wireless optical communication, since its license-free operation, large bandwidth, low electronmagnetic interference, and the realize of both communication and lighting. Visible light communication is recongnized as the direction of the next generation of wireless communication. Camera communication is known as a kind of visible light communication, using camera as Rx.There are more and more cameras in the intelligent devices, which has brought unprecedented attention to camera communication research field. As another kind of wireless optical communication, UV communication has many advantages such as high-security, long distance transmission, works reliablely in radio silence environment, which makes it a special position in the field of special communication.The paper starts with the research of optical communication modulation,and tries to realize a new modulation. An MISO UVC system is built,so as to the camera communication system. In the end, the parameters of the camera communication system are given. The main work and innovation of this paper are summarized as follows:First, the paper describes the basic structure of the wireless optical communication system, modulation. A new modulation named PAMSM(Paluse Amplitude Modulation Subcarrier Modulation, PAMSM) is proposed,the circuit of then proposed UV communication system is also designed and realized.Second, an UVC communication system based on the multiple input single output technology and its digital filtering method are proposed in the paper. By setting up the experimental system and completing the system testing,it comes out that the transmitter of the proposed MISO UVC communication system is designed successfully. The received signal is as desired, and the digital filtering method has remarkable effect on the wave filtering.Third, a camera communication system based on UDPAMSM(Under-Sampled Digital Paluse Amplitude Modulation Subcarrier Modulation,UDPAMSM) modulation is proposed and demonstrated, the result shows that by taking advantage of the proposed new modulation, we improve the system spectral efficiency to as much as 2bits/Frame/s.