A method and apparatus for improving millimeter wave channel simulation radio frequency resolution

Abstract

The application discloses a method and device for improving millimeter wave channel simulation radio frequency resolution, which comprises the following steps: judging whether the target radio frequency resolution is higher than the radio frequency resolution of a millimeter wave up-down conversion module; if the target radio frequency resolution is higher than the radio frequency resolution of the millimeter wave up-down conversion module, combining a small-scale fading module algorithm to compensate the radio frequency resolution in the channel processing process; interpolating the channel coefficient obtained after the radio frequency resolution is improved; down-converting the input millimeter wave signal with a higher frequency to a lower frequency baseband and converting to generate a corresponding digital signal; and operating the interpolated channel coefficient and the converted digital signal to obtain a millimeter wave radio frequency signal simulated by a channel. The application compensates the problem of low radio frequency resolution of the millimeter wave up-down conversion module caused by hardware limitation, improves the radio frequency resolution of the entire millimeter wave channel simulation system, and provides more abundant and more accurate signal information.

Description

Technical Field

[0001] This invention relates to the field of millimeter-wave communication technology, and specifically to a method and apparatus for improving the radio frequency resolution of millimeter-wave channel simulation, which can solve the problem of insufficient radio frequency resolution caused by up-conversion and down-conversion when performing millimeter-wave channel simulation. Background Technology

[0002] Channel simulation refers to modeling and simulating channels in a communication system to better understand their characteristics and behavior. In a communication system, a channel refers to the medium through which signals are transmitted, which can be wireless (air, fiber optic, cable, etc.). Channel simulation uses mathematical models and simulation techniques to simulate the transmission process of signals in a specific channel, considering factors such as signal attenuation, noise, and distortion. This helps in designing and optimizing communication systems, predicting signal performance under specific environments, and selecting appropriate modems, encoding / decoding schemes, or signal processing algorithms to improve the performance and reliability of the communication system. Channel simulation can be based on theoretical mathematical models or through computer software simulation experiments. This method allows for a better understanding and evaluation of channel behavior, providing important references and guidance for the design and optimization of communication systems.

[0003] Radio frequency (RF) resolution refers to the resolution capability in the radio frequency (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 represents the smallest interval between adjacent frequencies that can be distinguished in the spectrum. High RF resolution means a clearer ability to distinguish frequency differences between signals, which is crucial for spectrum monitoring, spectrum analysis, and signal identification. In RF systems, RF resolution can also refer to processing and analysis capabilities, including techniques for extracting and processing RF signal features, and the ability to identify different signals or waveforms. In RF equipment, resolution may also refer to the instrument's own ability to distinguish signals, such as the resolution of spectrum analyzers and RF signal generators, 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 emission simulation. Large-scale fading is caused by signal attenuation due to obstacles, terrain, weather, and other factors encountered during propagation. Small-scale fading is characterized by occurring within a very short time and exhibiting rapid waveform changes. Time delay refers to the varying arrival times of signals due to different path lengths during propagation. Noise refers to interference caused by various random factors during signal transmission, leading to signal distortion and reduced signal quality.

[0005] Millimeter-wave channel simulation typically uses high-frequency radio frequency (RF) hardware to model millimeter-wave channels. These hardware devices operate in the millimeter-wave band and can generate or receive high-frequency signals, or employ up-conversion / 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 the higher-frequency signal.

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

[0007] (1) Stability of local oscillator frequency

[0008] Phase noise: Phase noise represents the frequency jitter or instability of the local oscillator signal, which leads to spectral broadening. Assuming the phase noise is L(f), its effect can be used as a lower bound for RF resolution:

[0009] Δf RF ≥Δf LO =L(f)×f Lo ;

[0010] Where Δf LO This frequency instability is caused by phase noise. Lower phase noise means higher frequency stability and better RF resolution.

[0011] Frequency drift: During long-term use, the local oscillator frequency may drift, with the frequency drift amount being Δf. drift It also limits frequency resolution.

[0012] Δf RF ≥Δf drift .

[0013] (2) Filter bandwidth

[0014] Ideal Filter: For an ideal narrowband filter, its bandwidth BW defines the lower limit of frequency resolution.

[0015]

[0016] The narrower the filter bandwidth, the smaller the smallest frequency difference that can be distinguished, and the higher the RF resolution.

[0017] Practical filters: Practical filters are affected by component quality factors (Q factors) and manufacturing tolerances, which may lead to insufficient out-of-band rejection, thus affecting RF resolution. The impact of practical filters can be expressed as:

[0018]

[0019] Where Q is the quality factor of the filter.

[0020] (3) Linearity and isolation of the mixer

[0021] Harmonics and spurious signals: Mixers generate harmonics and spurious signals, affecting the frequency selectivity of the system. Assume the frequency offset introduced by the mixer's nonlinearity is Δf. MIX Then the radio frequency resolution can be expressed as:

[0022] Δf RF ≥Δf MIX ;

[0023] Improving the linearity and isolation of the mixer can reduce Δf MIX This improves radio frequency resolution.

[0024] Taking all the above factors into account, the radio frequency resolution Δf RF It can be represented as:

[0025]

[0026] The RF resolution of millimeter-wave upconversion modules is affected by a combination of factors, including local oscillator stability, filter bandwidth, and mixer performance. To meet the RF resolution requirements of a specific application, these factors need to be considered comprehensively. Due to hardware limitations, the RF resolution of millimeter-wave upconversion modules often fails to meet the requirements. Summary of the Invention

[0027] This invention addresses the problem of low analog RF resolution in millimeter-wave channels using up-conversion modules. It proposes a method and apparatus to improve the analog RF frequency resolution of millimeter-wave channels. The method combines millimeter-wave up-conversion modules with a small-scale fading module to compensate for the insufficient RF resolution accuracy of the up-conversion modules. The high RF resolution output signal helps identify and distinguish different signal sources and interference sources, enabling the system to more effectively combat interference, improve the fault tolerance of the communication system, more effectively allocate and manage spectrum resources, increase frequency band utilization, and contribute to improving the receiving performance and transmission stability of wireless communication systems. It also provides a clearer and more reliable foundation for signal processing and analysis.

[0028] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0029] In a first aspect, the present invention discloses a method for improving the analog radio frequency resolution of millimeter-wave channels, the method comprising the following steps:

[0030] Determine the target radio frequency resolution Δf tar Is it higher than the RF resolution Δf of the millimeter-wave up / down conversion module? mmRF If the target's RF resolution is higher than the RF resolution of the millimeter-wave up / down conversion module, Δf mmRF>Δf tar The following formula is used in conjunction with the small-scale fading module algorithm to compensate for radio frequency resolution during channel processing:

[0031]

[0032] Where h represents the channel coefficient obtained after improving the RF resolution, j is the imaginary unit, and f s Where N is the sampling frequency, and N represents the length of the signal;

[0033] Interpolate the channel coefficients obtained after improving radio frequency resolution;

[0034] The input high-frequency millimeter-wave signal is down-converted to a lower-frequency baseband signal and then converted to generate the corresponding digital signal.

[0035] The interpolated channel coefficients are then used in conjunction with the converted digital signal to obtain a millimeter-wave radio frequency signal that has undergone channel simulation.

[0036] Furthermore, the range of the interpolation multiples is:

[0037]

[0038] In the formula, F us F represents the sampling rate of the host computer. bs K is the sampling rate of the lower-level machine; K is the number of points received by the lower-level machine; N is the sampling rate of the lower-level machine. * The interpolation factor is [value]; the target RF resolution is [value]. A and B are adjustment parameters.

[0039] Secondly, the present invention discloses a device for improving the resolution of radio frequency simulation in millimeter-wave channels. The millimeter-wave channel simulator includes a physical channel, a radio frequency transceiver module, an up-conversion module, an analog-to-digital converter, a digital-to-analog converter, an FPGA digital signal processing module, and a host computer.

[0040] The physical channel sends the input millimeter-wave signal to the radio frequency transceiver module, which amplifies, attenuates, and filters the millimeter-wave radio frequency signal before sending it to the up-conversion module. The down-conversion module down-converts the higher-frequency millimeter-wave radio frequency signal to the lower-frequency baseband.

[0041] The analog-to-digital converter converts the down-converted output signal into a digital signal and inputs it into the FPGA digital signal processing module for channel simulation; the FPGA digital signal processing module, in conjunction with the small-scale fading module algorithm, performs radio frequency resolution compensation during channel processing;

[0042] The FPGA digital signal processing module converts the processed digital signal into an analog signal via a digital-to-analog converter. The analog signal is then up-converted to generate a millimeter-wave radio frequency signal, converting the low-frequency baseband signal into a high-frequency millimeter-wave radio frequency signal. The millimeter-wave radio frequency signal is then filtered and its gain is adjusted before being output.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] First, the method and apparatus of the present invention for improving the radio frequency resolution of millimeter-wave channel simulation compensates for the problem of low radio frequency resolution caused by hardware limitations in millimeter-wave up-conversion modules, improves the radio frequency resolution of the entire millimeter-wave channel simulation system, provides richer and more accurate signal information, and solves the problem of insufficient radio frequency resolution caused by using up-conversion when performing millimeter-wave channel simulation.

[0045] Secondly, the method and apparatus for improving the resolution of simulated radio frequency in millimeter-wave channels of the present invention, while improving resolution, does not cause additional logic resource consumption in the lower-level machine by reusing the algorithm of small-scale fading modules. This improves the scalability and flexibility of the millimeter-wave simulation system, reduces resource contention, and thus supports the integration of more functional modules. This helps to improve system performance, fault tolerance, and spectrum management efficiency, while also providing more possibilities for further research in signal processing and communication technologies.

[0046] Third, the method and apparatus of the present invention for improving the analog radio frequency resolution of millimeter-wave channels can achieve high radio frequency resolution output signals, thereby providing richer data for the field of signal processing and promoting in-depth research on signal characteristics, communication modes and wireless environments. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the millimeter-wave channel simulator of the present invention;

[0048] Figure 2 This is a schematic diagram of the FPGA signal processing process;

[0049] Figure 3 This is a schematic diagram illustrating the principle of high-resolution interpolation. Detailed Implementation

[0050] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0051] This invention discloses a method for improving the analog radio frequency resolution of millimeter-wave channels, the method comprising the following steps:

[0052] Determine the target radio frequency resolution Δf tar Is it higher than the RF resolution Δf of the millimeter-wave up / down conversion module?mmRF RF resolution Δf mmRF Depending on the hardware performance, the RF resolution of upconversion and downconversion modules will vary. If the target's RF resolution is higher than that of the millimeter-wave upconversion and downconversion module, Δf mmRF >Δf tar The following formula is used in conjunction with the small-scale fading module algorithm to compensate for radio frequency resolution during channel processing:

[0053]

[0054] Where h represents the channel coefficient obtained after improving the RF resolution, j is the imaginary unit, and f s Where N is the sampling frequency, and N represents the length of the signal;

[0055] Interpolate the channel coefficients obtained after improving radio frequency resolution;

[0056] The input high-frequency millimeter-wave signal is down-converted to a lower-frequency baseband signal and then converted to generate the corresponding digital signal.

[0057] The interpolated channel coefficients are then used in conjunction with the converted digital signal to obtain a millimeter-wave radio frequency signal that has undergone channel simulation.

[0058] Figure 1 This is a schematic diagram of the device (millimeter-wave channel simulator) for improving the RF frequency resolution of millimeter-wave channels according to the present invention. The millimeter-wave channel simulator includes a physical channel, an RF transceiver module, an up-conversion module, an analog-to-digital converter, a digital-to-analog converter, an FPGA digital signal processing module, and a host computer.

[0059] The physical channel sends the input millimeter-wave signal to the radio frequency transceiver module, which amplifies, attenuates, and filters the millimeter-wave radio frequency signal before sending it to the up-conversion module. The down-conversion module down-converts the higher-frequency millimeter-wave radio frequency signal to the lower-frequency baseband.

[0060] The analog-to-digital converter converts the down-converted output signal into a digital signal and inputs it into the FPGA digital signal processing module for channel simulation; the FPGA digital signal processing module, in conjunction with the small-scale fading module algorithm, performs radio frequency resolution compensation during channel processing;

[0061] The FPGA digital signal processing module converts the processed digital signal into an analog signal via a digital-to-analog converter. The analog signal is then up-converted to generate a millimeter-wave radio frequency signal, converting the low-frequency baseband signal into a high-frequency millimeter-wave radio frequency signal. The millimeter-wave radio frequency signal is then filtered and its gain is adjusted before being output.

[0062] The physical channel inputs a millimeter-wave signal. The channel simulator receives the millimeter-wave radio frequency signal through radio frequency sampling. After amplification, attenuation, and front-end filtering, the received millimeter-wave radio frequency signal undergoes downconversion to lower frequency baseband. The basic downconversion process is as follows:

[0063] (1) Mixer: A mixer is used to multiply (or mix) an input signal with a signal generated by a local oscillator. The output signal of the mixer will contain the frequency components of the original signal and the frequency components of the local oscillator, producing a combination of the difference and sum of the two frequencies.

[0064] (2) Filtering: The signal output from the mixer needs to be filtered to select the desired frequency components and remove unwanted components. Typically, filters are used to select and extract the desired lower frequency components.

[0065] The basic formula for downconversion can be used to describe the frequency of the mixer output signal:

[0066] f out =|f in -f LO |

[0067] Among them, f out It is the frequency of the signal output by the mixer, f. in f is the frequency of the input signal. LO It is the frequency of the local oscillator. This formula means 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.

[0068] The down-conversion output signal is converted from an analog signal to a digital signal by an analog-to-digital converter. Its working principle is as follows:

[0069] (1) Sampling: Analog signals are sampled into discrete samples over a certain time interval. The sampling frequency must be at least twice the highest frequency of the signal in order to accurately reconstruct the original signal.

[0070] (2) Quantization: The sampled continuous analog signal is converted into a discrete digital signal. The quantization process maps the analog signal to the nearest discrete value.

[0071] The digital signal output from the digital-to-analog converter is fed into the FPGA for digital signal processing to simulate a channel. The channel simulation process is based on a tapped delay line model and implemented using a transverse filtering method. The expression for the channel impulse response is:

[0072]

[0073] Where h(t) represents the impulse response function in the time domain, N represents the number of time delay lines or paths, and α i τ represents the attenuation coefficient of the i-th delay line. i Let δ(t) represent the time delay of the i-th time delay line, and let δ(t) represent the unit impulse function.

[0074] The channel coefficients required for channel simulation need to be generated by the host computer (main computer). Users can generate the channel coefficients to be simulated by configuring the host computer parameters and then input them into the FPGA to perform calculations with the input digital signal to obtain the output signal after channel simulation, such as... Figure 2 As shown.

[0075] The FPGA output signal is converted from digital to analog signal by a digital-to-analog converter. Its working principle is as follows:

[0076] (1) Digital quantization: The digital signal input to the digital-to-analog converter exists in discrete digital form. These numbers are usually generated by a computer or digital signal processor and represent sample values ​​of the signal.

[0077] (2) Reconstructing the analog signal: The digital-to-analog converter converts these discrete digital samples into analog signals. This process typically involves weighted summation of the digital samples to convert them into continuous analog voltage or current signals.

[0078] The output signal of the digital-to-analog converter is up-converted to generate a millimeter-wave radio frequency signal. Its working principle is similar to that of down-conversion, which converts the low-frequency baseband signal into a high-frequency millimeter-wave radio frequency signal. Finally, the millimeter-wave radio frequency signal is filtered and the gain is adjusted before being output.

[0079] This invention proposes a method that combines millimeter-wave up-conversion modules and small-scale fading modules in the channel simulation system to improve the RF resolution of the entire millimeter-wave channel simulation system, providing richer and more accurate signal information. This helps to improve the system's performance, fault tolerance, and spectrum management efficiency, while also providing more possibilities for further signal processing and communication technology research.

[0080] Specifically, assuming the RF resolution of the millimeter-wave upconversion module is Δf mmRF The required radio frequency resolution is Δf tar First, determine whether the target's RF resolution is higher than that of the millimeter-wave up / down converter module. If the target's RF resolution is lower than that of the millimeter-wave up / down converter module, i.e., Δf mmRF ≤Δf tarThen, there is no need to combine a small-scale fading module to improve its resolution; if the target's RF resolution is higher than the RF resolution of the millimeter-wave up-conversion module, i.e., Δf mmRF >Δf tar This requires combining a small-scale fading module algorithm with RF resolution compensation during channel processing to improve the overall RF resolution of the millimeter-wave channel simulation system. The main calculation formulas are as follows:

[0081]

[0082] Where h represents the channel coefficient obtained after improving the RF resolution, j is the imaginary unit, and f s is the sampling frequency, and N represents the length of the signal.

[0083] The small-scale fading module needs to interpolate the channel coefficients that improve the radio frequency resolution transmitted from the host computer, such as... Figure 3 As shown. Let the number of points received by the lower-level machine be K, and the number of interpolation output points be K², then the achievable frequency resolution is... Where N* is the interpolation factor, F bs This represents the sampling rate of the lower-level machine.

[0084] The higher the frequency resolution, the greater the interpolation factor, assuming the number of receiving points and the baseband sampling rate remain constant. Since the channel coefficients are generated by the host computer, the host computer needs to determine a sampling rate to generate the coefficients before interpolation and match them with the baseband sampling rate after interpolation. Assume the host computer's sampling rate is F. us The relationship between the sampling rate of the lower-level machine and the sampling rate is as follows:

[0085]

[0086] The frequency resolution of the host computer is then:

[0087]

[0088] Interpolation increases the signal sampling rate, effectively broadening the spectrum, and convolves it with a window function to reduce spectral leakage. To minimize leakage, the following conditions must be met:

[0089] F us >>Δf tar

[0090] Δf tar >>Δf u

[0091] Take F us >AΔf tar With Δf tar >BΔf u Then the range of interpolation factors can be obtained:

[0092]

[0093] Depending on the requirements, appropriate A and B parameters can be selected to perform interpolation, thereby realizing a millimeter-wave channel simulation system with high radio frequency resolution.

[0094] The present invention, through the combination of the millimeter-wave up-conversion module and the small-scale fading module, can not only improve the radio frequency resolution of the millimeter-wave channel simulation system and provide richer and more accurate signal information, but also improve the performance of the millimeter-wave channel simulation system by reusing the algorithm of the small-scale fading module without causing additional logic resource consumption.

[0095] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take 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 code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0096] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, produce instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0097] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0098] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment, causing a series of operational steps to be executed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that run on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0099] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0100] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for improving the analog radio frequency resolution of millimeter-wave channels, characterized in that, The method includes the following steps: Determine the target radio frequency resolution Δf tar Is it higher than the RF resolution Δf of the millimeter-wave up / down conversion module? mmRF If the target's RF resolution is higher than the RF resolution of the millimeter-wave up / down conversion module, Δf mmRF >Δf tar The following formula is used in conjunction with the small-scale fading module algorithm to compensate for radio frequency resolution during channel processing: Where h represents the channel coefficient obtained after improving the RF resolution, j is the imaginary unit, and f s Where N is the sampling frequency, and N represents the length of the signal; Interpolate the channel coefficients obtained after improving radio frequency resolution; The input high-frequency millimeter-wave signal is down-converted to a lower-frequency baseband signal and then converted to generate the corresponding digital signal. The interpolated channel coefficients are then used in conjunction with the converted digital signal to obtain a millimeter-wave radio frequency signal that has undergone channel simulation.

2. The method for improving the analog radio frequency resolution of millimeter-wave channels according to claim 1, characterized in that, The range of the interpolation multiples is: In the formula, F bs K is the sampling rate of the lower-level machine; K is the number of points received by the lower-level machine; N is the sampling rate of the lower-level machine. * The interpolation factor is [value]; the target RF resolution is [value]. A and B are adjustment parameters; take F. us >AΔf tar With Δf tar >BΔf u By satisfying F us >>Δf tar and Δf tar >>Δf u To adjust the values ​​of parameters A and B, where the host computer's frequency resolution... F us This represents the sampling rate of the host computer.

3. An apparatus for improving the analog radio frequency resolution of millimeter-wave channels based on the method of claim 1 or 2, characterized in that, The device includes a physical channel, a radio frequency transceiver module, a frequency up / down 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 filters the millimeter-wave radio frequency signal before sending it to the up-conversion module. The down-conversion module down-converts the higher-frequency millimeter-wave radio frequency signal to the lower-frequency baseband. The analog-to-digital converter converts the down-converted output signal into a digital signal and inputs it into the FPGA digital signal processing module for channel simulation; the FPGA digital signal processing module, in conjunction with the small-scale fading module algorithm, performs radio frequency resolution compensation during channel processing; The FPGA digital signal processing module converts the processed digital signal into an analog signal via a digital-to-analog converter. The analog signal is then up-converted to generate a millimeter-wave radio frequency signal, converting the low-frequency baseband signal into a high-frequency millimeter-wave radio frequency signal. The millimeter-wave radio frequency signal is then filtered and its gain is adjusted before being output.

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