Research On Broadband Communication Technology Of Air-ground Data Link Based On OFDM,CCSK And FDMA

UAV data link is a communication link based on a specific communication protocol for data transmission.The data transfer between the air vehicle platform and the ground receiving terminal is transmitted by radio.It ensures the reliability of the information transmission of the various functional units in the UAV system.With the rapid development of advanced sensor technology and the wide application in intelligence reconnaissance platform,the amount of information detected by aerial platform is increasing,the development of broadband data link with large amount of data transmission has become the most important thing.With the aid of the broadband data link,the large information capacity and high data transmission rate of the aerial UAV platform to the ground data receiving terminal is realized.Therefore,carrying out research on broadband data link for large capacity information transmission has extremely important theoretical and practical significance.First of all,the mechanism of air-ground data link communications system has been studied,the composition and key technology of the data link system in the air-ground data link are analyzed,and focus on the general broadband data link.Secondly,on this basis,a communication model of "One Station Controls Several Vehicles" is designed,and the air-ground data link communication system based on OFDM,CCSK and FDMA technology is completed.In the process of broadband signal generation in the air-ground data link,the mechanism of CCSK message mapping and modulation mode message mapping achieve the bit rate conversion of data stream and realize the adaptive selection of modulation mode;Base on the signal modulation and demodulation mechanism of OFDM Technology,the high-speed serial data stream is decomposed into a number of parallel low speed data streams to achieving the high speed data transmission rate;FDMA multiple access mechanism enables multiple users to share the entire bandwidth and achieve real-time communication with the ground data terminal at the same time.In the process of broadband signal reception in the air-ground data link,the original signal is recovered by the signal demodulation and message reflection mechanism,and frequency domain and constellation domain of the received signal are simulated in the condition of different SNR,it is verified that the system can satisfy the data transmission rate and reliability by choosing different modulation modes.Furthermore,aim at the problem of ICI in the broadband communication system using multi-carriers modulation technology,the generation of ICI in multi-carriers modulation system and the effect of ICI on communication system are analyzed in detail.On the basis of the above,the paper proposes a method to eliminate the ICI,the simulation results show that the improved ICI method can effectively improve the system performance.Finally,the anti interference of the broadband communication system in the space of the open space is studied,including the effectiveness analysis of anti-jamming,anti-multipath interference and anti audio interference,finally the simulation results are given.