Leo Satellite Mobile Communication Channel Model And Its Hardware Implementation

Comparing with the fixed-line communication networks and the terrestrial wireless communication systems, the satellite mobile communication system has been a hot spot in the research field due to its wide coverage and convenience to provide the global service. Among kinds of satellite communication systems, the LEO satellite communication system has very wide prosperity because its orbit is low and it has less communication delay, less path loss and flexible network organization. In order to provide the LEO satellite communication system with good performance, the important issues need to do is to study the channel propagating characteristic and build feasible channel models. Meanwhile, the implementation of the channel simulator is so significant that it can provide a strong debug method for the system design and testing.Communication performance is affected by many factors during its transmission in the LEO satellite communication channel. This paper considers the multi-path fading and shadowing, Doppler frequency offset, noise and free space loss, and builds the channel models based on these considerations which is the theoretical basis of the design of LEO satellite mobile channel simulators. The common research on the transmission property of satellite mobile communication channel is analyzed by software simulation generally, which lacks hardware experimental platform. Base on this requirement, our lab had finished the design work of the base band LEO satellite communication channel simulator, which had got the third prize (The third class reward of Science & Technology of National Defense). On this basis, we carried out the project named "LEO Satellite Mobile Communication Channel Simulator". After proposing the new design scheme, the hardware implementation of the LEO satellite communication channel simulator has been finished and been sent to the subscriber for working.This thesis is organized as follows:· We give a brief introduction of three fading channel models with common use in satellite communication study. It provides the theoretical basis for farther study of LEO satellite mobile channel model.· Considering the doppler frequency offset, transmission noise and free space loss, we build the channel model of LEO satellite communication system and study the realization techniques of each part of theoretical model.· Explain the hardware implementation of the LEO satellite communication channel simulator in details: Design the signal processing circuit with digital radio technology; Use bandpass sampling to digitalize the samples of IF analog signals; Lay out the PCB design of the mix signals circuit. · Test the specification of the LEO satellite communication channel simulator.