Research On Key Techniques Of Broadband Satellite Channel Simulator

Today, in the highly developed information world, satellite communication systems have been widely used in all walks of life. But using real satellite link to experiment is very expensive. However, use of satellite channel simulator which can truly simulate the satellite channel will greatly reduce development costs and improve efficiency. Because of Ka-band’s high bandwidth and strong anti-jamming features, it was widely used in broadband satellite communications.Therefore, this paper specifically research and implement a broadband satellite channel simulator of Ka-band.There is a variety of factors that affect the satellite communications, including channel fading, channel delay, channel noise and so on. For the Ka-band satellite channel, rain fading is the main factor that affect the communication. This article first reserched the Ka-band satellite channel model. Based on the result of reserch, this paper designed a Ka-band satellite channel simulator which based on FPGA hardware and can be controlled by users.Firstly, the paper reserached the characteristics of Ka-band satellite channel. It mainly be affected by rain fading. So, we propose a method to simulate the rain fading which based on the Markov state transition. And carried out a simulation to proof it’s correctness.Then, the Gaussian noise generation method has been studied. Noise of Ka-band satellite channel is mainly Gaussian noise. According to Central Limit Theorem, Gauss sequence can be get by adding multiple evenly distributed. The method to generating an evenly distributed include linear recursive congruence, multiplicative congruence, m-sequence, and so on. Simulate all the method all above by matlab.Researched how to select the initial seed to get excellent performance of Gaussian noise.We designed satellite channel simulator on the FPGA, according to the theoretical study and simulation results. And considered a variety of factors, such as hardware resource consumption during the design process.The design on hardware include sampling and filtering, SNR and power control, channel fading, channel noise,channel delay,and so on. How to control the channel simulator through PCI interface is also a key factor.Finally, we tested the channel simulator parameters, such as delay, the dynamic range of signal to noise ratio, band flatness, channel bandwidth. As the testing result, the index fully meet the system requirements. And compared with the channel simulators which are representative in the world. As can be seen from the results, the channel simulator degigned in this paper have breakthroughs in functionality and performance.