Capacity Analysis Of UWA MIMO Channel Based On Statistical Characteristion

With the implementation of the marine strategy and the actual needs of the military operations at sea, the demand of the underwater acoustic channel is greatly increasing. As a very important factor to measure the underwater acoustic channel state, underwater acoustic channel capacity is of great significance and value. The limited bandwidth is the main factor to restrict high speed underwater acoustic communication. However, MIMO(Multiple Input Multiple output) technology can improve the bandwidth utiliza tion of the wireless MIMO communication system, so MIMO in underwater acoustic communication has great potential for application. At present, the calculation of underwater acoustic channel capacity includes two methods which are field measurement and computer simulation. Moreover, the underwater acoustic channel model is divided into static and dynamic channel model. At present, the research on dynamic underwater acoustic channel capacity model is not much.The model established in this thesis is a kind of MIMO channel model based on channel statistical characteristics and ray propagation theory. It is a dynamic model which satisfies the characteristics of randomness and time-varying, which is much closer to complex sea situation. The newer and more accurate channel model incorporates physical laws of acoustic propagation( transmission loss, bottom and surface reflections, multipath and the Doppler shifting), as well as the effects of inevitable random local displacements. In this paper, the SISO(Single Input Single Output) channel model is established firstly, then its channel capacity is analyzed. Next, the model is extended to the MIMO channel and a large number of simulation experiments on Matlab are done. Compared with the SISO channel capacity, the MIMO channel can improve the channel capacity and the spectrum utilization obviously. Through a lot of simulation, the influence of signal frequency, signal to noise ratio, transmission bandwidth, transmission distance and water depth on the capacity of SISO and 2 ?2 MIMO channel have been analyzed and researched.This time-varying MIMO underwater acoustic channel capacity simulation model overcomes the shortcomings of the underwater acoustic channel location uncertainty and environmental conditions change, but also effectively improves the channel capacity of the underwater acoustic channel. This channel satisfies the randomness which is much closer to the actual situation, and it is convenient for real-time monitoring. Some conclusions obtained from the simulation analysis have an important guiding significance in the study of channel performance simulation, design and measurement of underwater acoustic transmission system.