| Channel simulator can simulate the real wireless channel propagation environment in the laboratory environment,and has a wide range of applications.For example,in engineering,it can be applied to the performance test of various wireless communication equipment,greatly reducing the cost and cycle of equipment test;in academic research,it can be applied to channel modeling to verify the correctness of the model.With the development of network technology,communication technology is gradually developing from point-to-point communication to wireless information communication network.The traditional point-to-point channel simulator can not meet the needs of this kind of communication network.Therefore,this paper studies,designs and implements a channel simulator supporting wireless communication network simulation.The main work of this paper includes the following contents:(1)The transmission characteristics such as free space loss,multipath fading,shadow fading,Doppler frequency shift and probability distribution models such as Rayleigh distribution,rice distribution and logarithmic shadow distribution are studied to master the basic transmission characteristics of wireless channel.(2)The channel model of small-scale fading is analyzed and simulated,including Clarke statistical model,Jakes simulation model and its statistical model,and the statistical characteristics of each model are compared,so as to provide theoretical basis for the design and implementation of channel simulator.(3)In the process of channel modeling and channel simulator verification,channel measurement is essential,so this paper also designs and implements a multipath channel measurement system.The measurement system is based on software radio architecture,and uses FZC sequence with better autocorrelation as the detection sequence,which has high measurement accuracy,so as to provide a measurement method for the verification of channel simulator.(4)Two virtex-7 690 t FPGA chips are used to design and implement a channel simulator which has 16 receiving and transmitting channels and supports wireless communication network simulation.Because of the huge data throughput,the system adopts the symmetrical design,two FPGA chips processing together,and adopts the pipeline structure and parallel processing.The channel simulator can also simulate Doppler shift,Gaussian white noise,Rayleigh fading and rice fading.The system test results show that the channel simulator designed in this paper has good performance,and also supports the construction of complex electromagnetic environment,which has a certain practical value. |
