Study On Underwater Acoustic Communication Simulation Technique And Channels Estimation Algorithm For Environmental Monitoring In Far-reaching Sea

With the further implementation of the National Oceanic developing strategy,our country began to advance the strategic plan on the basis of deepening the shallow sea. Underwater acoustic communication will play an increasing role in marine environmental monitoring and engineering technology. Since the limitations of RF communication, optical communication and other underwater wireless communication, acoustic communications becomes the only viable mean of underwater long-range wireless communications. It has broad application prospects in the marine engineering equipment, communications and positioning, marine environmental monitoring, the exploration of marine resources, marine environmental monitoring, marine disaster prevention, marine military and national defense. In recent years, the theory and technology studies about underwater acoustic communication become a hot academic research. Under the huge demand, the research of underwater acoustic network and underwater acoustic sensor has been launched, more mature programs of wireless communications on land were gradually applied to underwater communication research.However, the underwater acoustic channel, with a large delay, time-varying intensity, high noise, strong multipath, serious Doppler shift and so on, is worse than land-based radio channel and satellite channel. Makes the existing wireless communication scheme can not be directly applied to underwater acoustic communication system. The complexity of underwater acoustic channel is a key factor for the development of acoustic communication.In addition, the study of acoustic communication is highly complex and specialized, it has difficulty in test, long cycle, big risky and uncertain factors that has led to a longer cycle, low efficiency and also a key factor of constraint for the development of underwater acoustic communication.Based on the above background, this paper, with the support of the National High Technology Research and Development Program project on " key technologies of the far-reaching sea environmental monitoring platform based on sensor network " and the National Natural Science Foundation of China, " fuzzy control method study on underwater acoustic sensor network control system ", carried out research methods of underwater acoustic channels estimation algorithm and hardware-in-loop simulation of underwater acoustic communication. The main creative work is as follows:1) For characteristics of underwater acoustic channel and different application conditions, Ipropose underwater acoustic channels multi-parameter estimation algorithm based on fractional Fourier transform. It can estimate the channel path number, delay and frequency offset with advantages of high accuracy and efficiency.2) Propose and implemented a hardware-in-loop simulation platform of underwater acoustic communication HLSP/UWAC design basic on SOPC technology, VC++ and Matlab. HLSP/UWAC based on SOPC technology is the core integrated four systems: algorithm simulation evaluation system, algorithm load system, field test sampling system and acoustic wave storage system, with high degree of automation, easy to expand, based on real underwater acoustic channel research, simulation and implementation, shielding the underlying complexity of the specific hardware design and communications systems to realize. In the study of direct sequence spread spectrum underwater acoustic communication system with CDMA system showed that HLSP/UWAC can effectively improve the water efficiency of acoustic communication technology research.3) Propose and implemented in-application programming (IAP) based on SOPC technology. During update process of underwater acoustic communication at the field testing, work of removable watertight equipment has the problem of low efficiency and high failure rate. In order to improve efficiency and reduce the failure rate of field testing, the In-Application Programming system for acoustic communications field test has been proposed and it has been designed to achieve in support of WiFi.