Method and device for improving millimeter wave channel simulation radio frequency resolution

Abstract

The invention discloses a method and a device for improving the analog radio frequency resolution of a millimeter wave channel, and the method comprises the steps: judging whether the target radio frequency resolution is higher than the radio frequency resolution of a millimeter wave up-down conversion module or not, and if the target radio frequency resolution is higher than the radio frequency resolution of the millimeter wave up-down conversion module, starting the millimeter wave up-down conversion module; performing radio frequency resolution compensation in a channel processing process by combining a small-scale fading module algorithm; interpolation is carried out on the channel coefficient obtained after the radio frequency resolution is improved; down-converting the input millimeter wave signal with higher frequency to a baseband with lower frequency, and converting to generate a corresponding digital signal; and carrying out operation on the interpolated channel coefficient and the digital signal generated by conversion to obtain a millimeter wave radio frequency signal subjected to channel simulation. According to the millimeter wave channel simulation system, the problem of low radio frequency resolution caused by hardware limitation of the millimeter wave up-down conversion module is compensated, the radio frequency resolution of the whole millimeter wave channel simulation system is improved, and richer and more accurate signal information is provided.

Description

Technical Field

[0001] The present invention relates to the field of millimeter wave communication technology, and in particular to a method and device for improving the radio frequency resolution of millimeter wave channel simulation, which can solve the problem of insufficient radio frequency resolution caused by using up and down frequency conversion when performing millimeter wave channel simulation. Background Art

[0002] Channel simulation refers to modeling and simulating channels in communication systems in order to better understand the characteristics and behavior of channels. In communication systems, channels refer to the medium for signal transmission, which can be air media, optical fibers, cables, etc. for wireless transmission. Channel simulation can use mathematical models and simulation techniques to simulate the transmission process of signals in specific channels, taking into account factors such as attenuation, noise, and distortion of signals. It helps to design and optimize communication systems, predict the performance of signals in specific environments in advance, and thus select appropriate modems, encoding and decoding schemes, or signal processing algorithms to improve the performance and reliability of communication systems. Channel simulation can be a mathematical model based on theoretical analysis, or it can be a simulation experiment conducted through computer software. This method can better understand and evaluate the behavior of channels, and provide important reference and guidance for the design and optimization of communication systems.

[0003] RF resolution refers to the resolution capability in the RF field, that is, the degree to which different signals or frequencies can be distinguished. In RF technology, resolution refers to the ability to distinguish different frequencies or waveforms in a spectrum or signal. In spectrum analysis, RF resolution refers to the minimum interval between adjacent frequencies in the spectrum. High RF resolution means the ability to more clearly distinguish the frequency differences between signals, which is very important for spectrum monitoring, spectrum analysis and signal identification. In RF systems, RF resolution can also refer to processing and analysis capabilities, including technologies used to extract and process RF signal features, and the ability to identify different signals or waveforms. In RF equipment, resolution may also refer to the instrument's ability to resolve signals, such as the resolution of spectrum analyzers, RF signal generators and other equipment, which are used to accurately measure or generate specific frequency signals.

[0004] Channel simulation mainly includes large-scale fading simulation, small-scale fading simulation, time delay simulation and noise spurious simulation. Large-scale fading is the attenuation caused by obstacles, terrain, weather and other factors encountered by the signal during the propagation process. The main feature of small-scale fading is that it occurs in a very short time and the waveform changes very quickly. Time delay refers to the different arrival times of the signal due to different path lengths during the propagation process, which will cause the signal to be delayed in time. Noise refers to the interference caused by various random factors during the signal transmission process, which will cause signal distortion and reduce signal quality.

[0005] Millimeter wave channel simulation usually uses high-frequency RF hardware to simulate millimeter wave channels. These hardware devices are capable of operating in the millimeter wave frequency band and can generate or receive high-frequency signals, or use up-down conversion modules to convert signals from baseband frequencies to higher carrier frequencies. This process usually involves mixing the baseband signal with a high-frequency signal to produce a higher frequency signal.

[0006] The RF resolution of the millimeter-wave up-and-down conversion module is mainly affected by the combined influence of factors such as the stability of the local oscillator, the filter bandwidth, and the mixer performance.

[0007] (1) Stability of local oscillator frequency Phase noise: Phase noise represents the frequency jitter or instability of the local oscillator signal, which will cause the spectrum to be broadened. Assuming the phase noise is 𝐿(𝑓), its impact can be used as a lower limit on the RF resolution: ; in It is the frequency instability caused by phase noise. Low phase noise means higher frequency stability and better RF resolution.

[0008] Frequency drift: During long-term use, the local oscillator frequency may drift. This will also limit the frequency resolution .

[0009] (2) Filter bandwidth Ideal filter: For an ideal narrowband filter, its bandwidth BW defines the lower limit of the frequency resolution: ; The narrower the filter bandwidth, the smaller the minimum frequency difference that can be distinguished, and the higher the RF resolution.

[0010] Real filter: Real filters are affected by component quality factor (Q factor) and manufacturing tolerances, which may result in insufficient out-of-band suppression, thus affecting RF resolution. The impact of real filters can be expressed as: ; Where Q is the quality factor of the filter.

[0011] (3) Linearity and isolation of mixer Harmonics and spurious signals: The mixer will generate harmonics and spurious signals, which will affect the frequency selectivity of the system. Assume that the frequency offset introduced by the nonlinearity of the mixer is , then the RF resolution can be expressed as: ; Improving mixer linearity and increasing isolation can reduce , thereby improving RF resolution.

[0012] Taking all the above factors into consideration, the RF resolution It can be expressed as: .

[0013] The RF resolution of the millimeter-wave up-down conversion module is affected by the combined influence of factors such as local oscillator stability, filter bandwidth, and mixer performance. If the RF resolution of a specific application is to be met, these factors need to be considered comprehensively. Due to hardware limitations, the RF resolution of the millimeter-wave up-down conversion module often does not meet the requirements. Summary of the invention

[0014] In view of the problem of low radio frequency resolution of millimeter wave channel simulation using up and down conversion modules, the present invention proposes a method and device for improving the radio frequency resolution of millimeter wave channel simulation, and compensates for the defect of insufficient radio frequency resolution accuracy of the up and down conversion modules by combining millimeter wave up and down conversion modules and small-scale fading modules. The output signal with high radio frequency resolution helps to identify and distinguish different signal sources and interference sources, so that the system can more effectively resist interference, improve the fault tolerance of the communication system, more effectively allocate and manage spectrum resources, improve frequency band utilization, help improve the receiving performance and transmission stability of the wireless communication system, and provide a clearer and more reliable signal processing and analysis basis.

[0015] In order to achieve the above technical objectives, the technical solution adopted by the present invention is: In a first aspect, the present invention discloses a method for improving the frequency resolution of millimeter wave channel analog radio frequency, the method comprising the following steps: Determine the target RF resolution Is it higher than the RF resolution of the millimeter wave up and down conversion module? If the target RF resolution is higher than the RF resolution of the millimeter wave up and down conversion module, , the following formula is used to compensate the RF resolution in the channel processing process in combination with the small-scale fading module algorithm: Where h represents the channel coefficient obtained after the output RF resolution is improved, j is the imaginary unit, is the sampling frequency, N represents the length of the signal; Interpolating the channel coefficients obtained after improving the RF resolution; Down-convert the input higher frequency millimeter wave signal to a lower frequency baseband, and convert it to generate a corresponding digital signal; The interpolated channel coefficients are operated on the digital signal generated by the conversion to obtain a millimeter wave RF signal simulated by the channel.

[0016] Furthermore, the interpolation multiple range is: In the formula, is the host computer sampling rate, is the sampling rate of the lower computer; K is the number of points received by the lower computer; is the interpolation multiple; the target RF resolution is ; A and B are adjustment parameters.

[0017] In a second aspect, the present invention discloses a device for improving the frequency resolution of millimeter wave channel simulation radio frequency, wherein the millimeter wave channel simulator includes a physical channel, a radio frequency transceiver module, an up and down frequency conversion module, an analog-to-digital converter, a digital-to-analog converter, an FPGA digital signal processing module and a host computer; The physical channel sends the input millimeter wave signal to the radio frequency transceiver module, which amplifies, attenuates, and performs front-end filtering on the millimeter wave radio frequency signal and then sends it to the up-down conversion module, which down-converts the higher frequency millimeter wave radio frequency signal to a lower frequency baseband through down-conversion; The analog-to-digital converter converts the down-converted output signal into a digital signal and transmits it to the FPGA digital signal processing module for channel simulation; the FPGA digital signal processing module combines the small-scale fading module algorithm to compensate for the radio frequency resolution during the channel processing; The FPGA digital signal processing module converts the processed digital signal into an analog signal through a digital-to-analog converter, the analog signal is up-converted to generate a millimeter-wave RF signal, and the low-frequency baseband signal is converted into a high-frequency millimeter-wave RF signal. The millimeter-wave RF signal is output after filtering and gain adjustment.

[0018] Compared with the prior art, the present invention has the following beneficial effects: First, the method and device for improving the RF frequency resolution of millimeter-wave channel simulation of the present invention compensate for the problem of low RF resolution of the millimeter-wave up and down conversion modules due to hardware limitations, improve the RF resolution of the entire millimeter-wave channel simulation system, provide richer and more accurate signal information, and solve the problem of insufficient RF resolution when using up and down conversion when performing millimeter-wave channel simulation.

[0019] Second, the method and device of the present invention for improving the frequency resolution of millimeter wave channel simulation radio frequency improves the resolution while multiplexing the algorithm of the small-scale fading module without causing additional logic resource consumption of the lower computer, thereby improving the scalability and flexibility of the millimeter wave simulation system and reducing resource competition, thereby supporting the integration of more functional modules, helping to improve the system's performance, fault tolerance and spectrum management efficiency, and also providing more possibilities for further research on signal processing and communication technology. Third, the method and device of the present invention for improving the radio frequency resolution of millimeter wave channel simulation can achieve high radio frequency resolution output signal, thereby providing richer data for the signal processing field and promoting in-depth research on signal characteristics, communication modes and wireless environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the millimeter wave channel simulator of the present invention; Figure 2 It is a schematic diagram of FPGA signal processing process; Figure 3 Schematic diagram of high-resolution interpolation principle. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0022] The present invention discloses a method for improving the frequency resolution of millimeter wave channel simulation radio frequency, the method comprising the following steps: Determine the target RF resolution Is it higher than the RF resolution of the millimeter wave up and down conversion module? , RF resolution The RF resolution of the up / down conversion module will vary depending on the performance of the hardware. If the target RF resolution is higher than the RF resolution of the millimeter wave up / down conversion module, , the following formula is used to compensate the RF resolution in the channel processing process in combination with the small-scale fading module algorithm: Where h represents the channel coefficient obtained after the output RF resolution is improved, j is the imaginary unit, is the sampling frequency, N represents the length of the signal; Interpolating the channel coefficients obtained after improving the RF resolution; Down-convert the input higher frequency millimeter wave signal to a lower frequency baseband, and convert it to generate a corresponding digital signal; The interpolated channel coefficients are operated on the digital signal generated by the conversion to obtain a millimeter wave RF signal simulated by the channel.

[0023] Figure 1 The structure diagram of the device for improving the radio frequency resolution of millimeter wave channel simulation (millimeter wave channel simulator) of the present invention. The millimeter wave channel simulator includes a physical channel, a radio frequency transceiver module, an up and down frequency conversion module, an analog-to-digital converter, a digital-to-analog converter, an FPGA digital signal processing module and a host computer; The physical channel sends the input millimeter wave signal to the radio frequency transceiver module, which amplifies, attenuates, and performs front-end filtering on the millimeter wave radio frequency signal and then sends it to the up-down conversion module, which down-converts the higher frequency millimeter wave radio frequency signal to a lower frequency baseband through down-conversion; The analog-to-digital converter converts the down-converted output signal into a digital signal and transmits it to the FPGA digital signal processing module for channel simulation; the FPGA digital signal processing module combines the small-scale fading module algorithm to compensate for the radio frequency resolution during the channel processing; The FPGA digital signal processing module converts the processed digital signal into an analog signal through a digital-to-analog converter, the analog signal is up-converted to generate a millimeter-wave RF signal, and the low-frequency baseband signal is converted into a high-frequency millimeter-wave RF signal. The millimeter-wave RF signal is output after filtering and gain adjustment.

[0024] The physical channel inputs the millimeter wave signal, and the channel simulator receives the millimeter wave RF signal through RF sampling. After the received millimeter wave RF signal is amplified, attenuated, and front-end filtered, it is down-converted to a lower frequency baseband through down-conversion. The basic down-conversion process is as follows: (1) Mixer: A mixer is used to multiply (or mix) the input signal with a signal generated by a local oscillator. The signal output by the mixer will contain the frequency components of the original signal and the local oscillator frequency components, producing a combination of the difference and sum of the frequencies of the two.

[0025] (2) Filtering: The signal output by the mixer needs to pass through a filter to select the desired frequency components and filter out the unnecessary parts. Usually, the filter is used to select and extract the desired lower frequency components.

[0026] The basic formula for down-conversion can be used to describe the frequency of the mixer output signal: in, is the signal frequency at the mixer output, is the frequency of the input signal, is the frequency of the local oscillator. This formula indicates that the frequency of the mixer output signal is equal to the absolute value of the difference between the input signal frequency and the local oscillator frequency.

[0027] The down-converted output signal is converted into a digital signal through an analog-to-digital converter (Analog-to-Digital Converter). The working principle is as follows: (1) Sampling: The analog signal is sampled into discrete samples within a certain time interval. The sampling frequency must be at least twice the highest frequency of the signal in order to accurately restore the original signal.

[0028] (2) Quantization: The continuous analog signal obtained by sampling is converted into a discrete digital signal. The quantization process maps the analog signal to the nearest discrete value.

[0029] The digital signal output by the digital-to-analog converter is transmitted to the FPGA for digital signal processing simulation channel. The channel simulation process is based on the tapped delay line model and is implemented by the lateral filtering method. The expression of the channel impulse response (ImpulseResponse) is: in, represents the impulse response function in the time domain, N represents the number of delay lines or paths, represents the attenuation coefficient of the ith delay line, represents the delay of the ith delay line, represents the unit impulse function.

[0030] The channel coefficients required for channel simulation need to be generated by the host computer (host computer). Users can generate the channel coefficients required for simulation by configuring the host computer parameters and pass them into the FPGA for operation with the input digital signal to obtain the output signal after channel simulation, such as Figure 2 shown.

[0031] The FPGA output signal is converted into an analog signal through a digital-to-analog converter. The working principle is as follows: (1) Digital quantization: The digital signal input to the digital-to-analog converter exists in the form of discrete numbers. These numbers are usually generated by a computer or digital signal processor and represent the sample values ​​of the signal.

[0032] (2) Reconstructing the analog signal: A digital-to-analog converter converts these discrete digital samples into an analog signal. This process usually involves weighted summing of the digital samples to convert them into a continuous analog voltage or current signal.

[0033] The output signal of the digital-to-analog converter is up-converted to generate a millimeter-wave RF signal. Its working principle is similar to down-conversion, which converts the low-frequency baseband signal into a high-frequency millimeter-wave RF signal. Finally, the millimeter-wave RF signal is filtered and gain adjusted for output.

[0034] The present invention proposes to improve the RF resolution of the entire millimeter-wave channel simulation system by combining the millimeter-wave up and down conversion modules and the small-scale fading modules in the channel simulation system, providing richer and more accurate signal information, which helps to improve the system's performance, fault tolerance and spectrum management efficiency, and also provides more possibilities for further signal processing and communication technology research.

[0035] Specifically, assuming that the RF resolution of the millimeter wave up and down conversion module is , the RF resolution required is First, determine whether the target's RF resolution is higher than the RF resolution of the millimeter wave up-down conversion module. If the target's RF resolution is lower than the RF resolution of the millimeter wave up-down conversion module, that is, , there is no need to combine the small-scale fading module to improve its resolution; if the RF resolution of the target is higher than the RF resolution of the millimeter-wave up-down conversion module, that is, It is necessary to combine the small-scale fading module algorithm to compensate for the RF resolution during the channel processing to improve the RF resolution of the entire millimeter wave channel simulation system. The main calculation formula is as follows: Where h represents the channel coefficient obtained after the output RF resolution is improved, j is the imaginary unit, is the sampling frequency, and N represents the length of the signal.

[0036] The small-scale fading module needs to interpolate the channel coefficients for improving the RF resolution transmitted by the host computer, such as Figure 3 As shown. Assuming the number of points received by the lower computer is K, and the number of interpolation output points is K2, the achievable frequency resolution is , where N is the interpolation multiple, is the sampling rate of the lower computer.

[0037] The larger the frequency resolution, the larger the interpolation multiple will be when the number of receiving points and the baseband sampling rate remain unchanged. Because the channel coefficients are generated by the host computer, a sampling rate needs to be determined on the host computer to generate the coefficients before interpolation to match the baseband sampling rate after interpolation. Assume that the host computer sampling rate is , and the relationship with the lower computer sampling rate is: Then the frequency resolution of the host computer is: After interpolation, the signal sampling rate increases, which is the spectrum broadening, and is convolved with the window function to reduce spectrum leakage. In order to avoid leakage to the greatest extent, the following conditions need to be met: Pick and , then the interpolation multiple range can be obtained: According to the requirements, appropriate A and B parameters can be selected to implement interpolation, thereby realizing a millimeter wave channel simulation system with high RF resolution.

[0038] The present invention can not only improve the RF resolution of the millimeter wave channel simulation system and provide richer and more accurate signal information through the method of combining the above-mentioned millimeter wave up and down conversion modules and small-scale fading modules, but also improve the performance of the millimeter wave channel simulation system by multiplexing the algorithm of the small-scale fading module without causing additional logic resource consumption.

[0039] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present application may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0040] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0041] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0042] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0043] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0044] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for improving the frequency resolution of millimeter wave channel simulation radio frequency, characterized in that: The method comprises the following steps: Determine the target RF resolution Is it higher than the RF resolution of the millimeter wave up and down conversion module? If the target RF resolution is higher than the RF resolution of the millimeter wave up and down conversion module, , the following formula is used to compensate the RF resolution in the channel processing process in combination with the small-scale fading module algorithm: Where h represents the channel coefficient obtained after the output RF resolution is improved, j is the imaginary unit, is the sampling frequency, N represents the length of the signal; Interpolating the channel coefficients obtained after improving the RF resolution; Down-convert the input higher frequency millimeter wave signal to a lower frequency baseband, and convert it to generate a corresponding digital signal; The interpolated channel coefficients are operated on the digital signal generated by the conversion to obtain a millimeter wave RF signal simulated by the channel.

2. The method for improving the frequency resolution of millimeter wave channel simulation radio frequency according to claim 1, characterized in that: The interpolation multiple range is: In the formula, is the host computer sampling rate, is the sampling rate of the lower computer; K is the number of points received by the lower computer; is the interpolation multiple; the target RF resolution is ; A and B are adjustment parameters.

3. A device for improving the frequency resolution of millimeter wave channel simulation radio frequency based on the method described in claim 1 or 2, characterized in that: The device includes a physical channel, a radio frequency transceiver module, an up-down frequency conversion module, an analog-to-digital converter, a digital-to-analog converter, an FPGA digital signal processing module and a host computer; The physical channel sends the input millimeter wave signal to the radio frequency transceiver module, which amplifies, attenuates, and performs front-end filtering on the millimeter wave radio frequency signal and then sends it to the up-down conversion module, which down-converts the higher frequency millimeter wave radio frequency signal to a lower frequency baseband through down-conversion; The analog-to-digital converter converts the down-converted output signal into a digital signal and transmits it to the FPGA digital signal processing module for channel simulation; the FPGA digital signal processing module combines the small-scale fading module algorithm to compensate for the radio frequency resolution during the channel processing; The FPGA digital signal processing module converts the processed digital signal into an analog signal through a digital-to-analog converter, the analog signal is up-converted to generate a millimeter-wave RF signal, and the low-frequency baseband signal is converted into a high-frequency millimeter-wave RF signal. The millimeter-wave RF signal is output after filtering and gain adjustment.

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