Design And Implementation Of Channel Simulator Based On FPGA And DSP

In order to verify the performance of the communication equipment, the communication equipment usually needs to be tested in the channel environment which is close to the actual transmission characteristic. Previously, the tests are taken in the method of external field test, that is, renting the real satellite link. Although the test results have high reliability, but it also caused a lot of waste of resources. The existing channel simulator products can only achieve a single channel environment, but their prices are too expensive, hindering the development process of wireless communications field to some degree. To save resources and reduce test costs, a scheme which used to design and implement a channel simulator based on FPGA and DSP is been presented in this paper. The design and implementation of the channel simulator is enough to complete the simulation of the signal transmission characteristics of multi channel environment in the laboratory conditions, and the whole parameters of the channel environment can be adjusted. In addition, the channel simulator designed by this paper was cheap, which provided convenience for testing the performance of mobile communication equipment, and had practical significance.The main work of this paper included the following contents:(1) On the basis of researches in transmission characteristics of free space loss, multipath fading, shadow fading, Doppler frequency shift and probability distributions of Rayleigh, Rician and lognormal, this paper leads to the three classical channel model of Suzuki, C. Loo and Corazza, which are needed to realize.(2) According to the design index, the chip is selected as the core in designing the system circuit, which provides the hardware foundation for the channel simulator system.(3) To provide driving core for the channel simulator, the key algorithms, like digital down converting and channel simulating, are been analyzed. On the basis of the analysis, the algorithms are been realized on software and their performances are been tested in software & hardware co-emulation way.(4) By controlling the FPGA and DSP to take read and write operations on thesame dual port RAM, the two-way communication between FPGA and DSP was realized, and the function of this part was verified to ensure the cooperation of FPGA and DSP.(5) Channel simulator system test platform was been set up to test the performance of the three classic channel model by observing the system input and output signal.Test results show that the design of the channel simulator system could achieve a good simulation of the three classic channel models,Suzuki, C.Loo and Corazza, meeting the design requirements of this paper.