The Research On Modeling And Simulation Systerm For The HF High Mobility Channel

HF communication uses the mechanism of ionospheric reflection of high-frequency electromagnetic waves to realize global-scale beyond-horizon communication,and it is widely used in Remote communication,mobile communication,and emergency communication.If the satellite communication system fails,HF communication is the main method,and sometimes the only,for the long-distance command and control of aircraft beyond the visual range.The HF channel modeling and simulation can effectively simulate the characteristics of the HF channel which is the basis for the performance analysis and evaluation of the HF communication system.To this end,this paper proposes a HF channel modeling and simulation program for high-speed aeronautical mobile communications.Compared with the widely used HF channel simulation program,the new simulation program can simulate the characteristics of HF high-speed aeronautical mobile channel.The details are as follows:1.Research on HF channel characteristics and current typical HF channel models.Based on the analysis of the physical characteristics of the HF channel,the general mathematical expression of the HF channel is derived.At the same time,the two typical HF statistical channel models,Watterson model and ITS model,are theoretically deduced.The Watterson model is improved by using random channel modeling method,and the channel simulation of the improved model is carried out.The simulation results show that the improved model can effectively solve the problem that the fading of each frequency component of multi-tone signal presents periodic correlation.2.Modeling and Simulation of HF aeronautical mobile channel.An HF aeronautical mobile channel model based on Watterson model is proposed by analyzing the influence of maneuvering state parameters such as maximum moving speed,acceleration,maneuvering frequency and trajectory on the time-varying Doppler frequency shift.The algorithm implementation of each module in the model is described detailedly.Single tone signals with carrier frequencies of 6MHz and 15 MHz are selected for channel simulation.The simulation results show that the model can effectively describe the timevarying fading characteristics of HF aeronautical mobile channel.3.Test and analyze the HF channel simulation system.The realization scheme of HF channel simulation system based on PC platform is given.The real-time simulation function of HF channel is realized by using GUI module and sound card data acquisition module in simulation software.Through the simulation test and analysis of HF channel in static scene and high-speed mobile scene,the feasibility of the channel simulation system is verified.In the static scenario,the functional modules of the channel simulation system are tested,including multipath module,Doppler shift and expansion module.The second is the overall test of the system.By comparing with the standard HF channel module encapsulated in the simulation software,the effectiveness of the channel simulation system in this subject to simulate HF channel fading is verified.The subject channel simulation system simulates the effectiveness of HF channel fading.In the highspeed mobile scenario,the channel simulation test is carried out for low,medium and high mobility scenarios.The simulation results show that the system can realize the differential simulation of HF mobile communication channels for different types of aircraft with different maneuvering states,and can realize the customized channel simulation in specific scenarios when the route path is known.