Research Of Hydro-acoustic Communication System Based On MC-CDMA Technology

In the contemporary society, as people's activity is increasing in the ocean, the demand of underwater communication is increasing. CDMA technology is the core technology of 3G, and OFDM is the key technology of the 4G in the future. The combination of CDMA and OFDM inherits the advantages of the two technologies in high-speed data transmission is of great advantage, and it has become the hot spot in underwater communication studies. CDMA and OFDM are researched in this paper, advantages and disadvantages of two kinds of technology are analyzed and compared, and studied the combination of the two kinds of technology, Studied emphatically MC-CDMA principle and realization method, and established the demodulation system based on FPGA with MC-CDMA solution.The main works and achievements are summerized as follows:1. Studied the basic principle and characteristics of CDMA, researched spread spectrum technology. Put forward a method to generate PN code without table look-up. Use a real time method to save hardware resources in the FPGA.2. Studied the basic principle and characteristics of OFDM, the symbol timing synchronization method combining the cyclic Prefix(CP) is researched, and Peak-to-Average Power Ratio(PAPR) reduce technology is put forward. Use a FFT/IFFT module to achieve modulation-demodulation in FPGA.3. Studied and analyzed several methods of combination of CDMA and OFDM technology. Introduced some existing technology of combination, and the principle and characteristics them.4. Established underwater communication system with MC-CDMA solution.5. Performed experiments in the library to test the system, has a good stability and good performance.