CN111211820B - Test device and test method for in-vehicle communication equipment oriented to the Internet of Vehicles - Google Patents

Abstract

The invention discloses a vehicle networking-oriented vehicle communication equipment testing device and a testing method, including a performance testing evaluation subsystem, a signal acquisition and processing subsystem and a channel simulation superposition subsystem; the performance testing evaluation subsystem includes a test scene configuration unit and a test analysis subsystem The evaluation unit, the signal acquisition and processing subsystem includes a signal synchronization unit and a plurality of signal conversion units, the channel simulation superposition subsystem includes a channel generation unit and a channel superposition unit; the output interface of the test scene configuration unit is connected with the channel generation unit and the signal synchronization unit The input interface is connected with the PCIE bus, the output interface of the channel generation unit is connected with the input interface of the channel superposition unit, the output interface of the signal synchronization unit is connected with the input interface of the signal conversion unit, and the output interface of the signal conversion unit is connected with the channel. The input interface of the superposition unit is connected, and the output interface of the channel superposition unit is connected with the input interface of the test, analysis and evaluation unit by a PCIE bus.

Description

Test device and test method for in-vehicle communication equipment oriented to the Internet of Vehicles

Technical field:

The invention relates to a vehicle networking-oriented vehicle communication equipment testing device and a testing method, belonging to the field of wireless information transmission, in particular to a testing method and an implementation device of vehicle-mounted communication equipment in complex urban scenarios.

Background technique:

The purpose of the Internet of Vehicles is to establish a vehicle-centric network communication system to realize intelligent traffic management and vehicle intelligent control, which can effectively reduce road congestion and improve road safety. In-vehicle communication equipment is the link between the vehicle and the vehicle (Vehicle-to-Vehicle, V2V) in the Internet of Vehicles, and it is also the key to ensure the normal operation of the entire in-vehicle network. The reliability and stability of its communication function are the focus of users and researchers. . At present, the software and hardware related to the testing and detection methods of traditional communication equipment are very mature and perfect. However, unlike traditional communication equipment, in-vehicle communication equipment is installed in the driving environment. Due to factors such as vehicle movement, terrain fluctuations, and weather conditions, the V2V communication environment is more complex than the traditional mobile communication environment, and the traditional test solution is difficult to extend. use. Although field measurement is an effective means to test vehicle communication equipment, it is expensive and difficult to reproduce the same scene when problems are found during the test process. Therefore, it is necessary to develop a method that can test vehicle communication equipment in a laboratory environment. installation.

To achieve reliable and effective testing of in-vehicle communication equipment, the key is to accurately simulate and reproduce V2V MIMO wireless communication scenarios. The V2V MIMO communication scenario is different from the traditional mobile communication scenario. The transceivers are in a fast-moving state, the communication distance between vehicles is short, and the obstacles are relatively close to the mobile terminal. In addition, most of the modeling for V2V MIMO communication scenarios only consider the straight driving environment. However, in the actual traffic environment, due to the influence of surrounding vehicles and facilities as well as traffic lights, the vehicle will experience acceleration or deceleration in the process of moving. And in turns and rough terrain, the vehicle will change its direction of motion. Therefore, combined with vehicle driving parameters and scenarios, this patent proposes a test solution and a hardware implementation device solution for in-vehicle communication equipment in complex urban scenarios, which are used to solve fast and effective testing of in-vehicle communication equipment in the future.

Invention content:

In order to effectively test the device performance of the in-vehicle communication equipment in complex motion scenarios, the present invention proposes an in-vehicle communication equipment test device and a test method for the Internet of Vehicles. The device can accurately simulate the V2V MIMO communication channel according to vehicle driving parameters and scenes condition and test the performance of in-vehicle communication equipment.

The present invention adopts the following technical solutions: an on-board communication equipment testing device oriented to the Internet of Vehicles, comprising a performance test evaluation subsystem, a signal acquisition and processing subsystem and a channel simulation superposition subsystem;

The performance test and evaluation subsystem includes a test scene configuration unit and a test analysis and evaluation unit, the signal acquisition and processing subsystem includes a signal synchronization unit and a plurality of signal conversion units, and the channel simulation and superposition subsystem includes a channel generation unit and a channel superposition. unit;

The output interface of the test scene configuration unit is connected with the input interface of the channel generation unit and the signal synchronization unit by a PCIE bus, the output interface of the channel generation unit is connected with the input interface of the channel superposition unit, and the signal synchronization unit The output interface of the unit is connected with the input interface of the signal conversion unit, the output interface of the signal conversion unit is connected with the input interface of the channel superposition unit, and the output interface of the channel superposition unit is connected with the input interface of the test analysis and evaluation unit Connect to PCIE bus.

The present invention also adopts the following technical solutions: a method for testing vehicle-mounted communication equipment oriented to the Internet of Vehicles, comprising the following steps:

In the first step, the user sets the communication scene through the test scene configuration unit on the performance test evaluation subsystem, and sets the driving trajectory parameters of the mobile transmitter (mobile transmitter, MT) and mobile receiver (mobile receiver, MR) respectively. Based on this, the system completes three-dimensional channel environment reconstruction and channel characteristic parameter estimation;

The second step is to transmit the channel characteristic parameters output by the test scene configuration unit to the channel generation unit through the PCIE bus, and the channel generation unit performs V2V MIMO channel modeling according to the channel characteristic parameters and calculates the fading factor and channel noise of each MIMO sub-channel;

In the third step, through the PCIE bus, the test scene configuration unit transmits the instruction to start the signal acquisition to the signal synchronization unit, and the signal synchronization unit generates an enabling signal and transmits it to a plurality of signal conversion units;

In the fourth step, multiple signal conversion units work simultaneously after receiving the enabling signal, and process the analog signal emitted by the antenna of the vehicle-mounted communication device to be tested into a digital signal;

The fifth step, the channel superposition unit multiplies and accumulates the digital signal and the fading channel after delaying according to the channel parameters, and superimposes the channel noise to obtain the digital component of the channel output signal;

The sixth step is to return the channel output signal output by the channel superposition unit to the test, analysis and evaluation unit through the PCIE bus. Statistical calculation of frame rate.

Further, the specific generation steps of the second step are as follows:

描述参数，方法如下：1) Calculate the speed v ⁱ (l) and direction of MT and MR movement

Describe the parameters as follows:

和

i∈{MT,MR}分别表示MT及MR初始的速度和角度；

和

分别表示加速度和角度的变化率；Wherein, l represents the discrete time sequence number in the time domain, and the time interval is denoted as T _u ;

and

i∈{MT,MR} represents the initial velocity and angle of MT and MR, respectively;

and

represent the rate of change of acceleration and angle, respectively;

2) Calculate the Doppler frequency f _k,m (l) of the m-th scattering branch of the k-th path, as follows:

in,

in the formula

为第k条传播路径中第m条散射支路的离开角或到达角；

为MT和第k条传播路径上的第一个散射体

(MR和第k条传播路径上最后一个散射体

)之间的初始距离；波长λ＝c₀/f₀，f₀和c₀分别为载波和光速；

is the departure angle or arrival angle of the mth scattering branch in the kth propagation path;

is MT and the first scatterer on the kth propagation path

(MR and the last scatterer on the kth propagation path

); wavelength λ=c ₀ /f ₀ , f ₀ and c ₀ are the carrier and the speed of light, respectively;

3) Linearly interpolate the Doppler frequency as follows

Among them, f'[uI+a] is the real-time Doppler frequency after interpolation; f[uI] and f[(u+1)I] are the Doppler frequencies at two adjacent moments before interpolation; I is Interpolation multiple; a=0,1,...I-1;

4) Calculate the position vector of the vehicle and the scatterer, and calculate the time-varying path delay τ _k (l) of each path through the position vector. The method is as follows:

表示

的位置矢量；Dⁱ(l)表示MT或MR的位置矢量；

表示虚拟链路的时延；in,

express

The position vector of ; D ⁱ (l) represents the position vector of MT or MR;

Indicates the delay of the virtual link;

D ⁱ (l)=D ⁱ +v ⁱ (l)·l (7)

D ⁱ is the initial position vector of MT or MR; vi ⁽ l) is the velocity vector of MT or MR;

5) Calculate the path gain _ck (l) as follows:

where ξ _k represents a Gaussian random variable; r _DS and σ _DS represent delay distribution and delay spread, respectively;

6) Calculate the fading factor h _p,q,k (l) of the kth propagation path between the qth transmit antenna of MT and the pth receive antenna of MR, as follows:

Among them, M is the number of scattering branches; T _s is the sampling interval; θ _k,m is the phase, which obeys the uniform distribution of [-π,π);

7) Calculate the channel noise n(l) as follows:

和

分别为一端固定时间内传输信号和高斯随机数的平均功率；g(l)为高斯随机数；U₁(l)和U₂(l)为两路独立随机变量且服从均匀分布；Among them, snr is the signal-to-noise ratio coefficient;

and

are the average power of the transmitted signal and the Gaussian random number in a fixed time at one end, respectively; g(l) is the Gaussian random number; U ₁ (l) and U ₂ (l) are two independent random variables and obey a uniform distribution;

Further, the specific generation steps of the fifth step are as follows:

1) Input the digital signal into the dual-port RAM for coarse delay;

2) Input the signal output by the dual-port RAM into the polyphase filter delay device (the number of phases is R) for fine delay;

3) Interpolate the channel fading factors h _{p, q, k} (l) with the system clock f, and perform anti-image filtering;

4) Calculate the channel output signal according to the delayed signal and the interpolated channel fading factor, the method is as follows:

表示时延域离散时间序号；y_p(l)和n_p(l)分别为经过信道传播后第p根接收天线接收到的离散信号及对应的信道噪声；X(l)＝[x₁(l)，x₂(l),…,x_Q(l)]^T为待测车载通信设备发射的离散信号；c_p,q,_k和τ_p,q,k(l)分别为第q根发射天线与第p根接收天线之间的第k条传播路径的路径增益和时延；K(t)为多径数目；

表示对离散时延取整。in,

represents the discrete time sequence number in the delay domain; y _p (l) and n _p (l) are the discrete signals received by the p-th receiving antenna after channel propagation and the corresponding channel noise; X(l)=[x ₁ ( l), x ₂ (l),...,x _Q (l)] ^T is the discrete signal emitted by the vehicle-mounted communication device to be tested; c _p,q , _k and τ _p,q,k (l) are the qth root respectively Path gain and delay of the kth propagation path between the transmit antenna and the pth receive antenna; K(t) is the number of multipaths;

Indicates that the discrete delay is rounded up.

The present invention has the following beneficial effects:

(1) The present invention introduces the vehicle driving trajectory and scene into the V2V MIMO channel model, which conforms to the real motion of the vehicle, and discretizes the channel model on this basis, which is easy to implement on hardware and is suitable for vehicle-mounted communication in any complex motion scene. equipment testing;

(2) The technology of multiple subsystems sharing the PCIE trigger bus not only solves the synchronization problem between MIMO input signals, but also makes the test device have a general, flexible and reconfigurable hardware architecture, which is suitable for any number of antennas. Performance testing of in-vehicle communication equipment.

Description of drawings:

Figure 1 shows a typical communication scenario of in-vehicle communication equipment.

FIG. 2 is an implementation scheme of the vehicle-mounted communication equipment testing device of the present invention.

FIG. 3 is a typical test scenario provided by the in-vehicle communication equipment test apparatus of the present invention.

FIG. 4 is a V2V MIMO channel characteristic simulated by the vehicle-mounted communication equipment test device of the present invention.

FIG. 5 is the test results of the constellation diagram and the frame error rate output by the vehicle-mounted communication equipment test device of the present invention.

Detailed ways:

The present invention will be further described below in conjunction with the accompanying drawings.

The in-vehicle communication equipment testing device for the Internet of Vehicles of the present invention includes a performance testing and evaluation subsystem, a signal acquisition and processing subsystem, and a channel simulation and superposition subsystem. The performance test and evaluation subsystem includes a test scene configuration unit 1-1 and a test analysis and evaluation unit 1-2, the signal acquisition and processing subsystem includes a signal synchronization unit 1-3 and a plurality of signal conversion units 1-4, and the channel simulation and superposition subsystem includes Channel generation unit 1-5 and channel superposition unit 1-6.

The output interface of the test scene configuration unit 1-1 is connected with the input interface of the channel generation unit 1-5 and the signal synchronization unit 1-3 by the PCIE bus, and the output interface of the channel generation unit 1-5 is connected with the input interface of the channel superposition unit 1-6. The interface is connected, the output interface of the signal synchronization unit 1-3 is connected with the input interface of the signal conversion unit 1-4, the output interface of the signal conversion unit 1-4 is connected with the input interface of the channel superposition unit 1-6, and the channel superposition unit 1- The output interface of 6 is connected with the input interface of the test analysis and evaluation unit 1-2 by a PCIE bus.

Consider that the vehicle-mounted communication device used as MT is equipped with Q-transmitting antennas. After the transmitted signals pass through the V2V MIMO channel (as shown in Figure 1), the user-defined MR configured with P-receiving antennas receives the signals received by the MR. The signal can be expressed as

Wherein, X(t)=[x ₁ (t), x ₂ (t),...,x _Q (t)] ^T is the vector signal transmitted by the vehicle-mounted communication device to be tested; Y(t)=[y ₁ (t ), y ₂ (t),...,y _P (t)] ^T is the vector signal received by the user-defined MR; N(t)=[n ₁ (t), n ₂ (l),...,n _P (l)] ^T is the channel noise vector; h _p,q (t,τ) is expressed as the p (p=1,2,...P)th receiving antenna and the qth (q=1,2,... .Q) Unit impulse response of subchannels between the root transmit antennas.

In order to make the purpose, technical solution and advantages of the present invention clearer, the following takes a vehicle-mounted communication device to be tested configured with two transmitting antennas as an example and combined with the accompanying drawings of the present invention, the technical solution is clearly and completely described.

Assuming that the user-defined MR is configured with two receiving antennas, the signal transmitted by the vehicle communication device to be tested can be expressed as

It can be seen that the vehicle communication equipment to be tested is equipped with two transmitting antennas, and the signal acquisition and processing subsystem needs to include two signal conversion units 1-4. The two signal conversion units 1-4 convert the two input signals x ₁ and x ₂ through the After analog-to-digital conversion, it is sent to the channel superposition unit 1-6, and the channel superposition unit 1-6 on the channel analog superposition subsystem processes the matrix operation in the above formula, superimposes the fading channel for the input signal and adds channel noise n ₁ and n ₂ , The obtained digital signal is sent back to the test, analysis and evaluation unit 1-2 through the PCIE bus, and finally the test, analysis and evaluation unit 1-2 demodulates and analyzes the signals y ₁ and y ₂ to evaluate the device performance of the vehicle-mounted communication device to be tested.

The specific implementation steps are as follows:

加速度

初始运动角度

角度变化率

以及MR的初始速度

加速度

初始运动角度

角度变化率

系统据此完成三维信道环境重构以及信道特征参数估计；In the first step, on the performance test and evaluation subsystem, the user selects the urban environment as a typical test scene through the test scene configuration unit 1-1, and sets the initial speed of the MT

acceleration

Initial movement angle

Angle change rate

and the initial velocity of the MR

acceleration

Initial movement angle

Angle change rate

Based on this, the system completes three-dimensional channel environment reconstruction and channel characteristic parameter estimation;

In the second step, through the PCIE bus, the channel characteristic parameters output by the test scene configuration unit 1-1 are transmitted to the channel generation units 1-5, and the channel generation units 1-5 perform V2V MIMO channel modeling according to the channel characteristic parameters and calculate the MIMO channel characteristics. Subchannel fading factor and channel noise;

In the third step, through the PCIE bus, the test scene configuration unit 1-1 transmits an instruction to start signal acquisition to the signal synchronization unit 1-3, and the signal synchronization unit 1-3 generates an enabling signal and transmits it to a plurality of signal conversion units 1-4 ;

In the fourth step, the plurality of signal conversion units 1-4 work simultaneously after receiving the enabling signal, and process the analog signal transmitted by the antenna of the vehicle-mounted communication device to be tested into a digital signal;

In the fifth step, the channel superposition units 1-6 multiply and accumulate the digital signal and the fading channel after delaying according to the channel parameters, and superimpose the channel noise to obtain the digital component of the channel output signal;

The sixth step is to return the channel output signal output by the channel superposition unit 1-6 to the test, analysis and evaluation unit 1-2 through the PCIE bus. After the test, analysis and evaluation unit 1-2 demodulates and analyzes the signal in real time, the constellation diagram Analysis, channel characteristics statistics and statistical calculation of bit error/frame rate.

Further, the specific generation steps of the second step are as follows:

以及MR移动的速度v^MR(l)＝12-0.5l，移动的方向

1) Calculate the speed of MT movement v ^MT (l)=2+0.4l with the time interval T _u =50ms, the direction of movement

and the speed of MR movement v ^MR (l) = 12-0.5l, the direction of movement

描述参数，方法如下：where the velocity v ⁱ (l) and direction of movement of MT and MR are calculated

Describe the parameters as follows:

和

i∈{MT,MR}分别表示MT及MR初始的速度和角度；

和

分别表示加速度和角度的变化率；Wherein, l represents the discrete time sequence number in the time domain, and the time interval is denoted as T _u ;

and

i∈{MT,MR} represents the initial velocity and angle of MT and MR, respectively;

and

represent the rate of change of acceleration and angle, respectively;

2) Calculate the Doppler frequency f _k,m (l) of the m-th scattering branch of the k-th path, as follows:

in,

in the formula

为第k条传播路径中第m条散射支路的离开角或到达角；

为MT和第k条传播路径上的第一个散射体

(MR和第k条传播路径上最后一个散射体

)之间的初始距离；波长λ＝c₀/f₀，f₀和c₀分别为载波和光速。本案例假设

服从Von Mises(VM) 分布，

f₀＝2.4GHz。

is the departure angle or arrival angle of the mth scattering branch in the kth propagation path;

is MT and the first scatterer on the kth propagation path

(MR and the last scatterer on the kth propagation path

); wavelength λ=c ₀ /f ₀ , where f ₀ and c ₀ are the carrier and the speed of light, respectively. This case assumes

Obey the Von Mises(VM) distribution,

f ₀ =2.4GHz.

3) Linearly interpolate the Doppler frequency as follows

Among them, f'[uI+a] is the real-time Doppler frequency after interpolation; f[uI] and f[(u+1)I] are the Doppler frequencies at two adjacent moments before interpolation; I is Interpolation multiple; a=0,1,...I-1. In this case, take I=1562.

4) Calculate the position vector of the vehicle and the scatterer, and calculate the time-varying path delay τ _k (l) of each path through the position vector. The method is as follows:

表示

的位置矢量；Dⁱ(l)表示MT或MR的位置矢量；

表示虚拟链路的时延；in,

express

The position vector of ; D ⁱ (l) represents the position vector of MT or MR;

Indicates the delay of the virtual link;

D ⁱ (l)=D ⁱ +v ⁱ (l)·l (7)

和

坐标为

D ⁱ is the initial position vector of MT or MR; vi ⁽ l) is the velocity vector of MT or MR; in this case, the initial coordinates of MT and MR are D ^MT =[0,0], D ^MR =[300,0 ],

and

The coordinates are

5) Calculate the path gain _ck (l) as follows:

Among them, ξ _k represents a Gaussian random variable; r _DS and σ _DS represent delay distribution and delay spread, respectively. In this case, take σ _DS = 0.32.

6) Calculate the fading factor h _p,q,k (l) of the kth propagation path between the qth transmit antenna of MT and the pth receive antenna of MR, as follows:

Among them, M is the number of scattering branches; T _s is the sampling interval; θ _k,m is the phase, which obeys the uniform distribution of [-π,π). In this case, M=128, _Ts =32us.

7) Calculate the channel noise n(l) as follows:

和

分别为一端固定时间内传输信号和高斯随机数的平均功率；g(l)为高斯随机数；U₁(l)和U₂(l)为两路独立随机变量且服从均匀分布；本案例中，取snr＝-10dB。Among them, snr is the signal-to-noise ratio coefficient;

and

are the average power of the transmitted signal and Gaussian random number in a fixed time at one end, respectively; g(l) is the Gaussian random number; U ₁ (l) and U ₂ (l) are two independent random variables and obey uniform distribution; in this case , take snr=-10dB.

Further, the specific generation steps of the fifth step are as follows:

1) Input the digital signal into the dual-port RAM for coarse delay;

2) Input the signal output by the dual-port RAM into the polyphase filter delay device (the number of phases is R) for fine delay;

3) Interpolate the channel fading factors h _{p, q, k} (l) with the system clock f, and perform anti-image filtering;

4) Calculate the channel output signal according to the delayed signal and the interpolated channel fading factor, the method is as follows:

表示时延域离散时间序号；y_p(l)和n_p(l)分别为经过信道传播后第p根接收天线接收到的离散信号及对应的信道噪声；X(l)＝[x₁(l)，x₂(l),…,x_Q(l)]^T为待测车载通信设备发射的离散信号；c_p,q,_k和τ_p,q,k(l)分别为第q根发射天线与第p根接收天线之间的第k条传播路径的路径增益和时延；K(t)为多径数目；

表示对离散时延取整。in,

represents the discrete time sequence number in the delay domain; y _p (l) and n _p (l) are the discrete signals received by the p-th receiving antenna after channel propagation and the corresponding channel noise; X(l)=[x ₁ ( l), x ₂ (l),...,x _Q (l)] ^T is the discrete signal emitted by the vehicle-mounted communication device to be tested; c _p,q , _k and τ _p,q,k (l) are the qth root respectively Path gain and delay of the kth propagation path between the transmit antenna and the pth receive antenna; K(t) is the number of multipaths;

Indicates that the discrete delay is rounded up.

The scenarios selected in this implementation case and the test results obtained can be illustrated by Figures 3-5: 1) Figure 3 shows the typical test scenarios set up in this case and the driving trajectories of MT and MR; 2) Figure 4 shows the The V2VMIMO channel characteristics simulated by the test device; 3) Figure 5 shows the test results such as the constellation diagram and the frame error rate output by the test analysis and evaluation unit 1-2 of the test device.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several improvements can be made without departing from the principles of the present invention, and these improvements should also be regarded as the invention. protected range.

Claims (3)

1. A test method for a vehicle-mounted communication equipment test device oriented to the Internet of Vehicles, the vehicle-mounted communication equipment test device for the Internet of Vehicles comprises a performance test evaluation subsystem, a signal acquisition and processing subsystem and a channel simulation superposition subsystem; The performance test and evaluation subsystem includes a test scene configuration unit (1-1) and a test analysis and evaluation unit (1-2), and the signal acquisition and processing subsystem includes a signal synchronization unit (1-3) and a plurality of signal conversion units (1-4), the channel simulation superposition subsystem includes a channel generation unit (1-5) and a channel superposition unit (1-6); The output interface of the test scene configuration unit (1-1) is connected with the input interface of the channel generation unit (1-5) and the signal synchronization unit (1-3) by a PCIE bus, and the channel generation unit (1- 5) The output interface is connected with the input interface of the channel superposition unit (1-6), the output interface of the signal synchronization unit (1-3) is connected with the input interface of the signal conversion unit (1-4), the The output interface of the signal conversion unit (1-4) is connected with the input interface of the channel superposition unit (1-6), and the output interface of the channel superposition unit (1-6) is connected with the test analysis and evaluation unit (1- 2) the input interface is connected with PCIE bus, it is characterized in that: described test method comprises the steps: In the first step, the user sets the communication scene through the test scene configuration unit (1-1) on the performance test and evaluation subsystem, and sets the mobile transmitter (MT) and mobile receiver (MR) respectively. According to the driving trajectory parameters, the system completes 3D channel environment reconstruction and channel characteristic parameter estimation; In the second step, through the PCIE bus, the channel characteristic parameters output by the test scene configuration unit (1-1) are transmitted to the channel generation unit (1-5), and the channel generation unit (1-5) first calculates the moving speed of the MT and MR v ⁱ (l) and direction

Describe the parameters, then calculate the Doppler frequency f _k,m (l) of the m-th scattering branch of the k-th path, and perform linear interpolation on the calculated Doppler frequency, and then calculate the vehicle and the scatterer. The position vector is used to calculate the time-varying path delay τ _k (l) of each path and further calculate the path gain c _k (l). After obtaining the Doppler frequency f _k,m (l), the path delay τ The fading factor h _p,q of the kth propagation path between the qth transmit antenna of MT and the pth receive antenna of MR can be calculated after these channel characteristic parameters _k (l) and path gain c _k (l). _,k (l), and finally calculate the channel noise n(l) to complete the modeling of the V2V MIMO channel; In the third step, through the PCIE bus, the test scene configuration unit (1-1) transmits the instruction to start collecting signals to the signal synchronization unit (1-3), and the signal synchronization unit (1-3) generates an enabling signal and transmits it to multiple Signal conversion unit (1-4); In the fourth step, the plurality of signal conversion units (1-4) work simultaneously after receiving the enabling signal, and process the analog signal transmitted by the antenna of the vehicle-mounted communication device to be tested into a digital signal; In the fifth step, the channel superposition unit (1-6) multiplies and accumulates the digital signal and the fading channel after delaying according to the channel parameter, and superimposes the channel noise to obtain the digital component of the channel output signal; In the sixth step, through the PCIE bus, the channel output signal output by the channel superposition unit (1-6) is returned to the test, analysis and evaluation unit (1-2), and the test, analysis and evaluation unit (1-2) demodulates the signal in real time. After analysis, perform constellation analysis, channel characteristic statistics, and statistical calculation of bit error/frame rate. 2. the test method of the in-vehicle communication equipment testing device oriented to the Internet of Vehicles as claimed in claim 1, is characterized in that: the concrete generation step of the second step is as follows: 1) Calculate the speed v ⁱ (l) and direction of MT and MR movement

Describe the parameters as follows:

Wherein, l represents the discrete time sequence number in the time domain, and the time interval is denoted as T _u ;

and

i∈{MT,MR} represents the initial velocity and angle of MT and MR, respectively;

and

represent the rate of change of acceleration and angle, respectively; 2) Calculate the Doppler frequency f _k,m (l) of the m-th scattering branch of the k-th path, as follows:

in,

in the formula

is the departure angle or arrival angle of the mth scattering branch in the kth propagation path;

is MT and the first scatterer on the kth propagation path

The initial distance between; wavelength λ=c ₀ /f ₀ , f ₀ and c ₀ are the carrier and the speed of light, respectively; 3) Linearly interpolate the Doppler frequency as follows

Among them, f'[uI+a] is the real-time Doppler frequency after interpolation; f[uI] and f[(u+1)I] are the Doppler frequencies at two adjacent moments before interpolation; I is Interpolation multiple; a=0,1,...I-1; 4) Calculate the position vector of the vehicle and the scatterer, and calculate the time-varying path delay τ _k (l) of each path through the position vector. The method is as follows:

in,

express

The position vector of ; D ⁱ (l) represents the position vector of MT or MR;

Indicates the delay of the virtual link; D ⁱ (l)=D ⁱ +v ⁱ (l)·l (7) D ⁱ is the initial position vector of MT or MR; vi ⁽ l) is the velocity vector of MT or MR; 5) Calculate the path gain _ck (l) as follows:

where ξ _k represents a Gaussian random variable; r _DS and σ _DS represent delay distribution and delay spread, respectively; 6) Calculate the fading factor h _p,q,k (l) of the kth propagation path between the qth transmit antenna of MT and the pth receive antenna of MR, as follows:

Among them, M is the number of scattering branches; T _s is the sampling interval; θ _k,m is the phase, which obeys the uniform distribution of [-π,π); 7) Calculate the channel noise n(l) as follows:

Among them, snr is the signal-to-noise ratio coefficient;

and

are the average power of the transmitted signal and Gaussian random number in a fixed time at one end, respectively; g(l) is a Gaussian random number; U ₁ (l) and U ₂ (l) are two independent random variables and obey uniform distribution. 3. the test method of the vehicle-mounted communication equipment test device oriented to the Internet of Vehicles as claimed in claim 2, is characterized in that: the concrete generation step of the 5th step is as follows: 1) Input the digital signal into the dual-port RAM for coarse delay; 2) Input the signal output by the dual-port RAM into the polyphase filter delayer with the phase number R for fine delay; 3) Interpolate the channel fading factors h _{p, q, k} (l) with the system clock f, and perform anti-image filtering; 4) Calculate the channel output signal according to the delayed signal and the interpolated channel fading factor, the method is as follows:

in,

represents the discrete time sequence number in the delay domain; y _p (l) and n _p (l) are the discrete signals received by the p-th receiving antenna after channel propagation and the corresponding channel noise; X(l)=[x ₁ ( l), x ₂ (l),...,x _Q (l)] ^T is the discrete signal emitted by the vehicle-mounted communication device to be tested; c _p,q,k and τ _p,q,k (l) are the qth root respectively Path gain and delay of the kth propagation path between the transmit antenna and the pth receive antenna; K(t) is the number of multipaths;

Indicates that the discrete delay is rounded up.

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