Research And DSP Implementation Of Channel Estimation Algorithms Based On Ultraviolet Communication System

Ultraviolet(UV) non-line-of-sight(NLOS) communication , which is based on the unique characteristics of UV atmospheric scattering , is a new means of communication. The performance of optoelectronic devices in recent years is to upgrade sharply, so this communication has been paid widespread attention and studied. UV communication is with high security, and it can be used for confidential communication in complicated environment, such as convoy security network formation, network formation of banks confidential communication, confidential information pass between the city buildings and so on.The subject is based on the establishment of the UV NLOS Communication system, aiming to implement the NLOS UV communication channel estimation. In line with the channel equalization, channel coding and modulation and demodulation modules, a good performance receiver system of the UV communication would be achieved. With many key technologies of wireless communication, such as training sequence in channel estimation, channel equalization in the LMS equalizer, and the final decision to use the maximum likelihood, can greatly reduce the loss brought about by complex atmospheric system performance of the UV transmission, reduce the error rate, improve UV NLOS communication performance. Combined with the existing prototype, research group study the UV non-line-communication channel estimation algorithm, and built to achieve channel estimation algorithm LMS software and hardware platform, reducing the error rate and improving the system data rate.During early time of this research, through literature research and analysis, UV scattering, UV transmission characteristics in the atmosphere, and the ultraviolet non-line communication systems have been understood clearly. The direction of domestic and international situation is also combed. Then, by referring to the ultraviolet atmospheric single scattering model, the mathematical model of the wireless channel, a UV system impulse response has been obtained. Based on a variety of commonly used channel estimation algorithm in wireless communications, a systematic and in-depth analysis are done, and the pros and cons of various algorithms are compared. The channel estimation algorithm for NLOS UV communication system performance has been worked out in theory and simulation. During the implementation of LMS algorithm-based channel estimation algorithm, the transmission data is designed as UV-frame structure suitable for UV communication system. A Barker code is as synchronization of the frame structure identification, and Gold sequences as the training sequence. Finally, the current prototype, using TI's high-performance DSP TMS320C6713 floating-point hardware platform as the master chip, real-time implementation the various channel estimation algorithms, and communication systems throughout the UV experiment, achieving lower BER requirements, the NLOS UV communication system transmission performance has improved.