Implementation Of V2V Channel Emulator Based Virtual Instrumentation

With the total number of cars in China exceeding 250 million,traffic problems are becoming increasingly serious.As an effective means to solve traffic problems,internet of vehicles(Io Vs)has also made remarkable achievements in smart city construction and improving travel efficiency.Therefore,it has developed rapidly in recent years.As a core component of the Io Vs system,on-board terminal equipment have emerged in endlessly in recent years.The key to the normal operation of Io Vs system is to ensure its stable communication during vehicle driving.Therefore,each manufacturers of on-board terminal equipment before the equipment put on the market need to carry out a comprehensive test.However,the cost of simply relying on the field measurement has made many manufacturers overwhelmed and the comprehensiveness of the test still cannot be guaranteed.In order to solve this problem,this paper constructs a simplified vehicle-to-vehicle(V2V)non-stationary multiple-input multiple-output(MIMO)channel model by introducing vehicle motion speed and direction parameters,and proposes an implementation scheme of channel emulator for this model based on the virtual instrument platform.Finally,according to the scheme,the development of the channel emulator is completed and the indoor and outdoor measurement proves that the emulator can effectively simulate the non-stationary characteristics of the channel in the V2 V dynamic scene,which can be applied to the rapid indoor test of on-board terminal equipment in the future.The main research work of this paper is as follows:(1)The basic theory of wireless fading channel,including channel type and propagation characteristics are studied.The typical V2 V MIMO communication system is studied from the angle of antenna and channel,and three kinds of channel models are compared.This paper adopts the modeling method of geometry-based stochastic model(GBSM)and introduces vehicle speed and direction parameters to construct a simplified V2 V MIMO channel model suitable for hardware implementation.The calculation method of key parameters in the model is given,a hardware algorithm for generating channel noise in real time is presented and the statistical characteristics of the model are analyzed to prove the correctness of the model.(2)The theoretical model of channel is discretized.According to the discrete model and based on the virtual instrument platform including Lab VIEW programming language,PXIe chassis and PXIe board card,the overall scheme design of V2 V MIMO channel emulator is presented.At the same time,the detailed implementation scheme is given from the software and hardware level respectively,and the software interface,channel algorithm and several hardware modules are realized accordingly.The function of hardware module and the algorithm of hardware implementation are simulated by using Lab VIEW,and the validity of each module is proved.(3)Indoor and outdoor test schemes are designed to test the designed channel emulator.In the room,the basic indicators of the emulator,including channel fading,channel correlation,channel noise and multipath time delay,are tested by using the software radio peripheral in conjunction with the spectrometer,oscilloscope and Matlab software.Outside,the channel is measured by in-car radio peripheral and compared with the simulation results.The indoor and outdoor tests show that the channel emulator developed in this paper can effectively simulate the V2 V channel,which has reference significance for the test of on-board terminal equipment and the construction of Io Vs.