Research On Microwave Wireless Channel Modeling Over 2D Rough Sea Surface Based On Stochastic Bridge Processes

In this paper, a channel modeling method for microwave propagation of the two dimensional time varying sea surface is proposed based on the theory of stochastic bridge process modeling in terrestrial multipath propagation environment, which is to solve the problem of radio wave propagation and microwave channel modeling in the typical sea conditions. In other words, the theory of stochastic bridge process is introduced to the channel modeling of sea surface microwave propagation which help us to analyze the microwave propagation characteristics under typical sea conditions,establish the electromagnetic simulation model and the statistical analysis model of multipath channel propagation environment and obtain the impulse response mathematical model of the random multipath over the sea surface wireless channel.The paper can be divided into three parts: building the electromagnetic computation model of two dimensional rough sea surface, statistically analyzing the propagation characteristics of random rays in the sea surface channel and establishing the microwave random multipath channel model of the two dimensional time varying rough sea surface.In the first part, typical linear and nonlinear sea surface models are first built with Fourier transformation and Creamer transformation based on the theory of the PM spectrum.The electromagnetic model of the sea surface under typical sea conditions is then simulated based on the geometrical theory of diffraction. Meanwhile, the estimation method of the effective scattering area is analyzed to meet the requirements of sea surface electromagnetic simulation. To improve the computing ability, a method of extending the simulation area of the rough sea surface is finally presented. And it's demonstrated the effectiveness of the extension method and detailed analyzed the optimum sample size of electromagnetic calculation for the rough sea surface.In the second part, the digital features of the number and time delay of random rays in microwave channels are analyzed based on the electromagnetic calculation model of the two-dimensional rough sea surface. It's discussed the specular reflection loss and diffuse reflection loss of incident wave under different frequencies and different incidence angles. At the same time, the reflection of foam are also discussed. The diffraction loss of the radio propagation over rough sea surface is finally analyzed.In the last part, microwave random multipath channel model of two dimensional time varying rough sea surface is established based on the extracted information of two dimensional sea surface channel parameters and the stochastic bridge process modeling method. On one hand,it's verified the feasibility and validity. On the other hand,it's analyzed the response characteristics of the microwave channel under typical sea conditions and typical incident wave parameters.