Study On Synchronization In Multi-carrier Mobile Underwater Acoustic Communication

The technology of underwater acoustic communication in the military, civil, marine resources development, marine environment, such as inspection has extraordinary significance. In underwater acoustic channel, how do mobile high-speed, high efficiency, high precision of communication is one of the hot researching directions in the field of underwater acoustic communication.Multi-carrier communication technology has advantages which are an anti-multipath, high bandwidth efficiency, and high-speed transmission of data, and Multi-carrier communication has broad prospects for development in the acoustic communication. In movement state, the multi-carrier performance of underwater acoustic communication has influenced seriously by wideband Doppler Effect cause of the relative movement of both side of the sender and receiver, so it need be designed to overcome effectively wideband Doppler Effect and improve communication performance which is the multi-carrier underwater acoustic communication system. In movement state, the technology of synchronization is the key of overcoming Doppler frequency shift in the communication, and the performance of communication has influenced.This paper mainly aims at the technology of synchronization in multi-carrier mobile underwater acoustic communication, and OFDM have been studied as an example. First, the technology principle and the various key technologies of multi-carrier communication are introduced in head of the thesis; accordingly, the necessity of synchronization is demonstrated in mobile communications. A number of synchronization technologies are researched mostly in mobile communications and the synchronization of time-domain and frequency are finished to avoid the wideband Doppler and the timing errors in the multi-carrier underwater acoustic communication; the four technologies are studied and simulated which are to examine frequency by using the single-frequency signal to synchronize, the block wideband Doppler synchronization combined with DFT technology, the synchronization of the multi-carrier combined with DSSS and synchronization technology of multi-carrier signal combined with the auxiliary sequences. For the first and the second project, they are studied and simulated in the different underwater acoustic channel when wideband Doppler is the artificial introduction; for the synchronization project of multi-carrier signal in the combination of DSSS signal, the feasibility of multi-carrier signal combined with DSSS is validated when the principle of direct sequence spread spectrum is discussed, and then, the synchronization algorithm is studied and simulated in different underwater acoustic channel; for the project of using the auxiliary sequences in multi-carrier signal, it is studied and simulated in different underwater acoustic channel and the wideband Doppler is the artificial introduction. At the end, the experiments need to be finished to verify the performance of the synchronization algorithms.