The Study Of Indoor Wireless Communication Technology Based On LED

Wireless communication technology based on indoor LED light source combines power line communication with LED light communication. Owing to LED's numerous advantages such as energy saving, durability, high reliability and quick response time, it has gradually been taking the place of the traditional light sources. At present, power line network has almost covered every corner of the world; we can make use of this existing network to set up LED light communication network, which will save overlapping investment for the network. But the phenomenon in this scheme caused by multipath effect and frequency selective fading is troublesome, so MC-CDMA is choosed for this paper which is based on OFDM and CDMA, it can effectively solve the problems of high noise, multi-path effect and frequency selective fading, and realize the multiplex of light source signals. Compared with traditional ways of communication, wireless communication based on indoor LED light source has the advantages of cost-saving, widespread coverage, zero radiation and high safety.The main jobs of this thesis are:(1) It summarized the technological advantages and characteristic of the LED visible light communication and power line communication, introduced their histories and current development situations, and analyzed the feasibility of wireless communication technology based on indoor LED light source. (2) It described the characteristics of power line communication system, analyzed the characteristics of power line transmission and in theory made the channel model of it.(3) It analyzed the necessity of the usage of the LED light source as the indoor lighting in the future. By the analysis of principles and characteristics of light-emitting, it designed a drive circuit for the purpose of both lighting and communication. In accordance with characteristics of the lighting, it designed a suitable lighting coverage layout, which satisfied the requirements of relevant international standards.(4) It elaborated the basic structure of the LED visible light communication system. By the study and analysis of several common LED light modulations, it chose the OOK modulation because it can be easily realized. It designed photoelectric detector, preamplifier and so on. And it modeled and simulated indoor LED visible light communication system.(5) It researched the LED communication system based on power line. It built the structure of the LED light communication system, proposed system simulation parameters and researched on the suppression and synchronization of PAPR by module. Finally multi-user signal is detected by multi-user detection algorithm with MMSE, Simulation results demonstrated when SNR is 16dB, BER is 5×10-4 in single user system, and in three users users environment, it is about 1.8×10-4, the proposed design accorded with standards of the indoor communication environment and met the requirements of the indoor communication.