The Design Of Video Transmission System Based On Transform Domain Communication Technology

With the increasingly complex electromagnetic environment of modern battlefield,the low efficiency and the general anti-interference performance of the direct spread system cannot meet the growing business need. The transform domain communication system is proposed to get the optimization of anti-interference performance and spectrum efficiency in the complex interference environment. The concept of cognitive radio is used in the transform domain communication technology, which can adjust the using spectrum to electromagnetic environment intelligently. Also, it applies the high order modulation method to improve the efficiency of information transmission. In all, it realizes interference perception, spectrum aggregation and efficient transmission of information in the complex electromagnetic environment.In this paper, the basic principle and key technology of the transform domain communication system(TDCS) are studied, and the performance of the system is analyzed. We also design and develop the transmitter and receiver principle prototype of TDCS based on FPGA of Altera DE3 Development board. The video transmission system based on TDCS is built with the video acquisition, the encoding and decoding circuit board and the analog up and down conversion module, which can realize the reliable transmission of video. The contents of this paper are:1, The basic principle and system structure of the communication system in the transform domain system are analyzed. The basic principle of each module is introduced. The classical spectrum estimation and modern spectral estimation of spectrum sensing technology are described. Cyclic Coding shift keying(CCSK) modulation technology CCSK demodulation and synchronization technology are analyzed.2,The influence of the random phase and the number of holes on the system is analyzed. Simulate bit error rate performance of the transform domain communication in Gauss white noise channel. Study the anti-interference ability in signal and multi tone interference on the TDCS system and compare the anti-interference performance with DSSS systems.3, Design the relevant parameters of high-definition video stream compression and decoding. Control the encoding and decoding circuit of HD video stream by PC program. Design, debug and test the analog up and down module. The interface between different boards is completed.4, The designs of transmitter and receiver of transform domain communication system on FPGA is accomplished. The system includes transmitter(video capture module, video encoding module, baseband module, upper frequency conversion module) and receiver(lower frequency conversion module, demodulation module, video decoding module, display screen). The dynamic adjustment of the demodulation matched filter is realized. And the whole system is debugged and tested.The video transmission system based on TDCS is designed, which realizes the transmission of HD video of 1280*720P. And ensure the communication in the case of interference signal ratio is 30 dB. The error rate of the system is under 410? when the EbN0 is 8dB.