Multi-Color Modulation And Indoor Optical Positioning Technology Research

In recent years, the rapid development of wireless communication has greatly facilitated people’s life style. But at the same time it also encountered a number of bottlenecks, such as limited spectrum resources, radiation and other issues. And visible light communication get into the sight of scholars because of "Green", "health", "high speed". In this paper, we study the modulation technology and the visible light positioning technology of the multi-color VLC system.First of all, the development of VLC, the native development of VLC, and the application of VLC are briefly introduced, and the results of previous studies are summarized. This paper further describes the indoor VLC system, mainly from the system overview, optoelectronic devices, channel analysis and modulation of the aspects of the indoor VLC system. The characteristics of the devices are introduced fromtwo aspects, i.e. the photoelectric device and the electro optical converter. In the channel analysis, we analyze the channel of the VLC system from the two aspects of the optical and electrical fields, and the characteristics of the system are described in detail. OOK modulation, PAM modulation and PPM modulation are introduced in the system of single-color VLC, and the advantages and disadvantages of the three modulation methods are described in detail. CIM modulation, CSK modulation and MM modulation technology are introduced in the system of multi-color VLC. Based on this, the paper makes a detailed study on the CSK based indoor multi-color visible light modulation technology. From the point of view of IEEE 802.15.7 standard, it discusses the difference of three kinds of different physical layer, and the CSK modulation system is introduced briefly. For the two different domains of CSK modulation, the color gamut and the LED domain, the model of the multi-color VLC system model is established, and simulation is made in two domains to study of the performance of CSK modulation. In this paper, the method of color gamut demodulation is improved, and the new decision area is made to compare with the traditional method. Then, this paper designs a kind of CSK and SM modulation named bipolar CSK modulation method. Firstly, the paper introduces the constraint of CSK modulation technology, which is non-negative. From the two aspects of the traditional spatial modulation and the generalized spatial modulation, the space modulation principle is described in detail. Aiming at the restriction of traditional CSK modulation, a new CSK mod-ulation method is designed, which is based on the combination of spatial modulation to break through the non negative characteristics of the signal. The performance difference between the modulation mode and the traditional CSK modulation is studied by simulation.In the end, the paper mainly studies the positioning technology in the indoor VLC system. This paper gives a systematic summary of the traditional indoor positioning system. Among them, it mainly include some indoor positioning technology and some of the optional technology introduction. Traditional indoor position-ing technology is mainly introduced the ultrasonic, infrared, RFID, blue-tooth, ultra-wide band and WLAN based indoor positioning technology. TOA, AOA, TDOA, RSSI and other methods are mainly introduced in this paper. On this basis, the paper is aimed at the problem of the lack of LEDs in the VLC communication, we propose a solution through a terminal with multiple PD. In this background, the system model is established, and the error of the positioning error is simulated and analyzed with the specific channel characteristics.