Design And Implementation Of Digital Baseband For Wireless Channel Simulato

Wireless channel simulators can simulate the transmission characteristics of signals in space,study the changes in received signal characteristics caused by the channel,restore the dynamic changes in signal transmission in space,and provide support for the development and testing of communication equipment.The research on high-performance wireless channel simulators in China is still in its infancy,and the relevant foreign products are still embargoed to China.In this context,the thesis focuses on the fading channel model and interference model of the wireless channel simulator,and carries out the following three aspects of research work.A channel model based on statistical properties is developed for standard and custom channels,and a flat fading channel is implemented using the shaped filter method.simulation results show that the channel fading achieved by this method can achieve the theoretical results.In the hardware implementation,the clock cycle required to process the sum of 64 multiplier results using a four-stage pipeline is reduced from 63 to 8,while the number of consumed registers only increases by 33.8%.For the simulation of Gaussian white noise channels,a combination of linear feedback shift registers and Box-Muller conversion algorithm is used to first generate uniformly distributed random numbers and then convert them to Gaussian distributed random numbers.The algorithm requires the calculation of logarithms,open squares and trigonometric functions.Traditional methods cannot meet the high accuracy requirements of the device,and propose the use of coordinate rotation numerical computation for iterative solution.The simulation results show that the output white noise satisfies the Gaussian distribution characteristics.The simulation of interfering signals requires high sweep ranges,long sweep times and comb spectra with multiple frequency points.Using conventional methods faces the problems of huge resource consumption and poor output results.The paper uses a combination of DDS and time division to control the output signal via a state machine.Simulation results show that the power distribution of the output interference spectrum is more uniform than that of the conventional method,with less interference between frequency points,and that the algorithm consumes only 1/N of the resources of the conventional algorithm(N is the number of comb spectrum frequency points).Finally,the thesis concludes with a summary of the research,a description of the applications of the research results and an outlook on the next steps to be undertaken.The research results of the thesis have been applied to the relevant core modules of our own wireless channel simulator equipment.