Implementation And Design Of Vhf Channel Simulator Based On SDR Platform

With the gradual development of wireless communication technology,ultrashort wave frequency band begins to occupy an important position in modern wireless communication,especially in military wireless communication,ultrashort wave wireless communication has become an important way of wireless communication.In this paper,based on the present situation of the modern wireless communication,a thorough understanding of ultrashort wave radio communication technology development present situation,ultrashort wave transmission characteristics of wireless channel for the theoretical study and simulation analysis,put forward in the software radio platform realizes the ultra-short wave channel simulator design,completed the construction of the channel interference module,and debugging on the software radio and the final structures,channel simulator test environment,the performance test of the simulator.Specific work is as follows:(1)this paper by ultrashort wave radio channel simulator based on market demand,this paper introduces the background and significance of the study design and market status quo existing products,compared with the existing channel simulator,this paper adopts the reconfigurable system,the software can upgrade the software radio platform as the core hardware module and the channel simulator to add human disturbance,simulating later can be optimized and high universality.(2)In this paper,single frequency interference,sweep interference,dressing interference and white noise interference are selected as the interference types of human interference module,and the channel transmission characteristic principle of ultra-short wave wireless communication and the realization principle of four kinds of human interference are analyzed,and these interference principles are simulated and verified.The classical VHF channel model is analyzed and compared,and the weighted small-scale fading of the irregular ground transmission channel model is selected as the main model of the environmental interference module of the VHF wireless channel simulator.(3)according to the design of the software working process and the demand of each module algorithm gives the hardware resources optimization scheme,this paper proposes a traditional FIFO IP core to realize the improvement of doppler frequency shift method,adopts the cascade method,introducing the multipath fading factor,reduce RAM the use of resources and the algorithm structure of channel simulation is more stable.In order to save the resources of the platform RF board,a new scheme to realize the large-scale fading characteristics is proposed in the single input and single output mode.By dividing the attenuation value into three parts for processing,the workload of the RF board is reduced and the transmitting power of the RF transmitting plate is stabilized.Based on the design of white Gaussian noise interference module,a method of overloading filter coefficients is proposed.The filter model with fixed order is used to overload different filter coefficient sets to achieve different bandwidths of filters,so as to better cover the target spectrum range and reduce the use of logic resources.(4)based on the design of simulator completed simulator platform to build,and completed the design and build,PC interface design of the system hardware validation protocols,and set up the test platform,the sequential control accuracy of the algorithm in FPGA verification,and then on the hardware simulation of analog signal interference,completed the simulator test plan,through the analysis of simulation results,proved the feasibility of the simulator system.