Artificial rainfall experiment method based on software defined radio

Abstract

The invention discloses an artificial rainfall experimental method based on software-defined radio, and the method comprises the steps: building an experimental system based on software-defined radio, and enabling the experimental system to comprise a software-defined radio transmitting module, a receiving module, an artificial rainfall device, an experimental environment control module and a data processing terminal, an artificial rainfall device is used for simulating environments with different rainfall intensities, and the rainfall intensities are monitored in real time; a preset test signal is generated and sent at a software-defined radio transmitting end, and a receiving end collects the signal and extracts channel state information; analyzing characteristic changes of channel state information data under different rainfall intensities, and extracting parameters such as signal amplitude attenuation and phase deviation; a mathematical model between rainfall intensity and signal characteristic changes is established, and the rainfall attenuation law is researched. Accurate analysis of the relation between the channel state information and the rainfall intensity under the artificial rainfall condition is achieved, the experimental environment is controllable, the result repeatability is high, and an important basis is provided for detecting environmental rainfall through wireless microwave signals.

Description

Technical Field

[0001] The present invention belongs to the field of meteorological monitoring, and in particular relates to an experimental method for studying the rain attenuation law of wireless signals in an artificial rainfall environment based on channel state information of software-defined radio. Background Art

[0002] In wireless communication systems, rainfall can affect signal propagation, causing changes in channel state information (CSI). Traditional research has focused on rain attenuation in high-frequency communications (such as millimeter-wave and terahertz communications), while ignoring the changing relationship between CSI and rainfall intensity in low-frequency communications. Using CSI data to perceive environmental rainfall has important applications, such as in intelligent transportation, agricultural monitoring, and disaster warning. However, existing research lacks a controllable and repeatable experimental method to systematically explore the relationship between CSI and rainfall intensity.

[0003] Traditional rain attenuation research methods are typically based on outdoor natural rainfall conditions. These limitations, such as difficulty controlling rainfall intensity, long experimental periods, and significant environmental noise, make accurate analysis of rain attenuation difficult. Furthermore, when attempting to conduct artificial rainfall experiments using software-defined radio technology, the high humidity generated by the sprinkler system causes systematic drift in signal characteristics, preventing the measured data from accurately reflecting the effects of actual rainfall. This phenomenon has never been addressed by existing patented technologies in previous natural rainfall studies. Furthermore, existing experimental methods often rely on fixed frequencies and simple channel models, lacking in-depth understanding of complex signal transmission characteristics.

[0004] In recent years, software-defined radio (SDR) technology has been widely used in wireless communication research due to its flexible software programmability and support for multiple frequency bands and protocols. However, direct application of SDR technology to artificial rainfall experiments presents three unique technical obstacles: ① Sudden changes in ambient humidity caused by the start and stop of sprinklers can lead to inaccurate baseline channel state information; ② Conventional signal acquisition modes smooth out transient characteristics caused by raindrop collisions; and ③ Different frequency bands have varying sensitivities to humidity, making it difficult to distinguish the mixed interference of rain, fog, and water. These issues make it difficult to directly obtain data on rain attenuation channel patterns, even with SDR equipment. Therefore, designing an SDR-based SDR-based artificial rainfall experiment method that can efficiently and accurately analyze the effects of rain attenuation on wireless signals is of great research value. Summary of the Invention

[0005] Purpose of the invention: The purpose of the present invention is to provide an artificial rainfall experiment method based on the CSI rain attenuation law of software-defined radio. By using software-defined radio equipment to obtain channel state information data of wireless signals under artificial rainfall conditions, the impact of rain attenuation on the transmission characteristics of wireless signals is analyzed, thereby solving the problems of uncontrollable natural rainfall conditions, long experimental cycles, and insufficient analysis accuracy in existing methods.

[0006] Technical Solution: To achieve the above objectives, the present invention provides the following technical solutions for the CSI rain attenuation law artificial rainfall experiment method based on software-defined radio:

[0007] 1) A software-defined radio (SDR)-based rain attenuation experimental system was constructed, consisting of a SDR transmitter / receiver module (using a USRP B210 device), an artificial rainfall device equipped with a piezoelectric ceramic nozzle, a multi-parameter environmental control chamber, and a GPU-accelerated data processing platform. To address the unique water mist interference problem in artificial rainfall environments, the transmitter module uses a programmable gate array chip to generate chaotic encrypted signals, producing test signals covering 300 MHz to 6 GHz (including OFDM signals and Gold sequence-encoded broadband signals). The receiver module uses a quantum particle swarm optimization algorithm for real-time signal demodulation, adds a humidity compensation factor, and adjusts the demodulation parameters by monitoring changes in ambient humidity in real time.

[0008] 2) An artificial rainfall device is used to simulate environments with different rainfall intensities. The artificial rainfall device generates raindrop groups that conform to the MP distribution through the water pressure regulation system (0.1-0.5MPa) and piezoelectric nozzle (0.5-2mm aperture) of the real-time control device. In order to solve the problem of sudden changes in humidity caused by the start and stop of the sprinkler system, a step-by-step pulse rainfall method is used to increase the intensity by 5mm / h every 5 minutes. The laser raindrop spectrometer and the acoustic sensor array are started synchronously to collect the raindrop size distribution and kinetic energy parameters, and all sensor data are synchronized at the μs level through the PTP protocol. The environmental control cabin maintains stable conditions of temperature ±0.5℃ and humidity ±3%RH, and dynamically compensates for the impact of environmental fluctuations on the measurement results through Kalman filtering;

[0009] 3) The transmitter module generates a test signal through a software-defined radio device, and the receiver module receives the signal and extracts channel state information, including signal amplitude, phase, and channel capacity;

[0010] 4) Collect channel state information data under different rainfall intensities and raindrop size distribution conditions, and analyze the relationship between the channel state information and the rainfall intensity and raindrop size medium characteristics based on the data processing terminal;

[0011] 5) Establish a mathematical model of rainfall intensity, raindrop size distribution and channel state information changes to obtain rainfall intensity for practical application.

[0012] Preferably, the artificial rainfall device simulates a variety of rainfall intensities and raindrop size distributions by adjusting the water flow rate and nozzle parameters, and is equipped with a rain gauge and a laser raindrop spectrometer for real-time monitoring of rainfall intensity and raindrop characteristics. The nozzle is made of piezoelectric ceramic material and can dynamically adjust the nozzle diameter by applying a 0-100V voltage to achieve millisecond-level precise control of raindrop size.

[0013] Preferably, the transmitting module generates multi-band, multi-standard test signals through software-defined radio equipment, including sine waves and orthogonal frequency division multiplexing (OFDM) signals, and embeds pseudo-random codes based on Gold sequences when generating the signals.

[0014] Preferably, the receiving module extracts channel state information including signal amplitude attenuation, phase offset and channel capacity change based on software defined radio equipment, and pre-processes the original channel state information data using a wavelet transform noise reduction algorithm.

[0015] Preferably, the data processing terminal uses a long short-term memory network to analyze and model the relationship between the channel state information data and the rainfall intensity.

[0016] Preferably, the experimental system controls temperature and humidity parameters through an environmental monitoring module, and adjusts temperature and humidity in real time according to environmental factors, so that the fluctuation range of environmental parameters is controlled within ±0.5°C and ±3%RH.

[0017] Preferably, the step (5) comprises the following steps:

[0018] The data processing terminal constructs a coupling model of rainfall intensity R, raindrop size distribution D, and channel state information CSI:

[0019]

[0020] Among them, the raindrop size distribution It can be calibrated in real time using a laser raindrop spectrometer; the dielectric constant ò(T) = 78.54 [1-0.0046 (T-25°C)], which can be calculated using temperature data from the environmental control module; the humidity compensation coefficient λ = 0.15, and the model solution uses an adaptive Monte Carlo integration algorithm;

[0021] The above formula can be used to obtain the functional relationship between rainfall intensity, raindrop size distribution and channel state information. After solving it, the reversible mapping relationship between the above three parameters can be obtained:

[0022]

[0023] in:

[0024]

[0025] The above formula can be used to obtain the inverse calculation formula of rainfall intensity for practical application.

[0026] In the present invention, (1) a software-defined radio device is used as a signal transmitter and receiver, connected to a transmitting antenna and a receiving antenna, respectively. The software-defined radio hardware adopts a dual-channel synchronous architecture, with the main channel transmitting the test signal and the auxiliary channel monitoring the ambient noise in real time. (2) At the transmitting end, a test signal of a specific frequency band is generated through the software-defined radio platform. The signal form may include a sine wave or an OFDM signal. (3) At the receiving end, the software-defined radio platform collects the received signal in real time and extracts the channel state information data.

[0027] In the present invention, (1) an artificial rainfall device (such as a sprinkler system) is used to simulate a rainfall environment. Different rainfall intensities are achieved by adjusting the water flow rate of the sprinkler system. The nozzle control system integrates an existing regulation algorithm and dynamically adjusts the water pressure based on the feedback from the laser raindrop spectrometer. (2) A rain gauge is equipped to monitor the rainfall intensity in real time and transmit the data to a data processing terminal. (3) An experimental environment control device is used to adjust the temperature, humidity and other parameters of the experimental environment.

[0028] In this invention, (1) under artificial rainfall conditions, the transmitter sends a test signal at a fixed power, and the receiver collects the signal and extracts channel state information. (2) The channel state information data under different rainfall intensities is analyzed to extract features such as signal attenuation and phase change. (3) A long short-term memory network is used to establish a machine learning model of rainfall intensity and signal attenuation. (4) An attention mechanism and a humidity feature input branch are added to the traditional LSTM structure to improve the accuracy of rainfall intensity prediction.

[0029] Beneficial Effects: The artificial rainfall simulation system enables precise control of rainfall conditions, improving the repeatability and operability of the experiment. The combination of a water mist interference signature library and a humidity compensation algorithm significantly reduces measurement errors in high-humidity environments. Software-defined radio technology is used to collect channel state information in real time, enabling precise analysis of the relationship between channel state information and rainfall intensity. The simple and efficient experimental method is suitable for studying environmental rainfall perception in low-frequency communications. The experimental results could provide important technical support for fields such as intelligent transportation, agricultural monitoring, and disaster warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural diagram of the artificial rainfall experiment system based on software-defined radio.

[0031] Figure 2 It is a structural diagram of the artificial rainfall device and the experimental environment control module.

[0032] Figure 3It is a data processing diagram of channel state information data under different rainfall intensities. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings.

[0034] like Figure 1 As shown, the experimental system of the present invention includes a software-defined radio (SDR) transmitter module, a software-defined radio (SDR) receiver module, an artificial rainfall device, an experimental environment control module, and a data processing terminal. The SDR transmitter module and receiver module are placed in the same experimental space via antennas, forming a wireless communication channel. The artificial rainfall device is located at the top of the experimental space and simulates environments with varying rainfall intensities through a spray system. The experimental environment control module is located outside the experimental space and utilizes constant temperature and humidity equipment to regulate parameters such as the experimental environment to ensure the stability and repeatability of experimental conditions. The data processing terminal is connected to the SDR equipment via Ethernet or USB to collect and analyze experimental data in real time.

[0035] like Figure 2 As shown in the figure, the artificial rainfall device consists of a sprinkler system, a rain gauge, and a control system. The sprinkler system can simulate various rainfall intensities by adjusting the water flow rate. The rain gauge measures rainfall intensity data in real time and transmits the data to the data processing terminal. The artificial rainfall device simulates different rainfall intensities (0-100 mm / h) and raindrop size distributions (0.1-5 mm) by adjusting the water flow rate and nozzle aperture (0.5-2 mm) of the sprinkler system. A laser raindrop spectrometer is used to measure the raindrop size, falling velocity, and number density in real time as characteristic parameters of the signal propagation medium. The experimental environment control module uses constant temperature and humidity equipment to adjust the temperature and humidity within the experimental space, specifically within the range of 15°C-35°C and 30%-90% to meet the needs of different experimental conditions.

[0036] like Figure 3 As shown in the figure, the software-defined radio transmission module generates test signals using software-defined radio equipment, including sine waves, orthogonal frequency division multiplexing (OFDM) signals, and other wideband signals. The transmitted signals cover the 300 MHz to 6 GHz frequency band, suitable for common wireless communication bands. As the signals pass through the experimental space, they are affected by rainfall, causing changes such as signal amplitude attenuation and phase shift. The receiving module receives the signals in real time using the software-defined radio equipment and extracts channel state information, including parameters such as signal amplitude, phase, and channel capacity. The received channel state information data is transmitted via the software-defined radio equipment to the data processing terminal for storage and analysis.

[0037] The data processing terminal first constructs a coupling model of rainfall intensity (R), raindrop size distribution (D), and channel state information (CSI):

[0038]

[0039] Among them, the raindrop size distribution The model can be calibrated in real time using a laser raindrop spectrometer. The dielectric constant (Ø(T)) is 78.54 [1-0.0046(T-25°C)], driven by temperature data from the environmental control module. The humidity compensation coefficient (λ) is 0.15. The model solver utilizes an adaptive Monte Carlo integration algorithm, achieving a real-time computation rate of 1200 times per second on NVIDIA GPU platforms.

[0040] The above formula can be used to obtain the functional relationship between rainfall intensity, raindrop size distribution and channel state information. After solving it, the reversible mapping relationship between the above three parameters can be obtained:

[0041]

[0042] in:

[0043]

[0044] The above formula can be used to obtain the inverse calculation formula of rainfall intensity for practical application.

[0045] Through Figure 1 、 Figure 2 、 Figure 3 The system setup and experimental steps shown in this paper enable precise measurement and modeling of the relationship between channel state information and rainfall intensity in an artificial rainfall environment. The experimental environment is controllable and the results are highly reproducible, providing reliable technical support for wireless communication system design and environmental rainfall monitoring.

[0046] An artificial rainfall experiment method based on software-defined radio is used to study the relationship between channel state information and rainfall intensity, including the following steps:

[0047] 1) Build an experimental system, including a transmitter module, a receiver module, an artificial rainfall device, an environmental monitoring module, and a data processing terminal. The transmitter module uses a USRPB210 device to generate a chaotic encrypted test signal covering 300MHz-6GHz. The receiver module uses a quantum particle swarm optimization algorithm to demodulate the signal and extract channel state information parameters.

[0048] 2) Using an artificial rainfall device to simulate environments with different rainfall intensities, raindrops of different particle size distributions are generated as signal propagation media, and an environmental monitoring module is used to collect experimental environmental factors such as rainfall intensity, raindrop size, temperature, and humidity in real time;

[0049] 3) The transmitter module generates a test signal through a software-defined radio device, and the receiver module receives the signal and extracts channel state information, including signal amplitude, phase, and channel capacity;

[0050] 4) Collect channel state information data under different rainfall intensities and raindrop size distribution conditions, and analyze the relationship between the channel state information and the rainfall intensity and raindrop size medium characteristics based on the data processing terminal;

[0051] 5) A mathematical model is established to determine the rainfall intensity, raindrop size distribution, and channel state information changes. The data processing terminal then constructs a coupling model of rainfall intensity R, raindrop size distribution D, and channel state information CSI.

[0052]

[0053] Among them, the raindrop size distribution It can be calibrated in real time using a laser raindrop spectrometer; the dielectric constant ò(T) = 78.54 [1-0.0046 (T-25°C)], which can be calculated using temperature data from the environmental control module; the humidity compensation coefficient λ = 0.15, and the model solution uses an adaptive Monte Carlo integration algorithm;

[0054] The above formula can be used to obtain the functional relationship between rainfall intensity, raindrop size distribution and channel state information. After solving it, the reversible mapping relationship between the above three parameters can be obtained:

[0055]

[0056] in:

[0057]

[0058] The above formula can be used to obtain the inverse calculation formula of rainfall intensity for practical application.

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A software-defined radio-based artificial rainfall experiment method for studying the relationship between channel state information and rainfall intensity, characterized in that: The following steps are involved: 1) Build an experimental system, including a transmitter module, a receiver module, an artificial rainfall device, an environmental monitoring module, and a data processing terminal. The transmitter module uses a USRPB210 device to generate a chaotic encrypted test signal covering 300MHz-6GHz. The receiver module uses a quantum particle swarm optimization algorithm to demodulate the signal and extract channel state information parameters. 2) Using an artificial rainfall device to simulate environments with different rainfall intensities, raindrops of different particle size distributions are generated as signal propagation media, and an environmental monitoring module is used to collect experimental environmental factors such as rainfall intensity, raindrop size, temperature, and humidity in real time; 3) The transmitter module generates a test signal through a software-defined radio device, and the receiver module receives the signal and extracts channel state information, including signal amplitude, phase, and channel capacity; 4) Collect channel state information data under different rainfall intensities and raindrop size distribution conditions, and analyze the relationship between the channel state information and the rainfall intensity and raindrop size medium characteristics based on the data processing terminal; 5) Establish a mathematical model of rainfall intensity, raindrop size distribution and channel state information changes to obtain rainfall intensity for practical application.

2. The artificial rainfall experimental method based on software defined radio according to claim 1, characterized in that: The artificial rainfall device simulates various rainfall intensities and raindrop size distributions by adjusting the water flow rate and nozzle parameters, and is equipped with a rain gauge and a laser raindrop spectrometer for real-time monitoring of rainfall intensity and raindrop characteristics. The nozzle is made of piezoelectric ceramic material, and the nozzle diameter is dynamically adjusted by applying a 0-100V voltage.

3. The artificial rainfall experimental method based on software defined radio according to claim 1, characterized in that: The transmitting module generates multi-band and multi-standard test signals through software-defined radio equipment, including sine waves and orthogonal frequency division multiplexing (OFDM) signals, and embeds pseudo-random codes based on Gold sequences when generating the signals.

4. The artificial rainfall experimental method based on software defined radio according to claim 1, characterized in that: The receiving module extracts channel state information including signal amplitude attenuation, phase offset and channel capacity change based on software defined radio equipment, and pre-processes the original channel state information data using a wavelet transform noise reduction algorithm.

5. The artificial rainfall experimental method based on software defined radio according to claim 1, characterized in that: The data processing terminal uses a long short-term memory network to analyze and model the relationship between channel state information data and rainfall intensity.

6. The artificial rainfall experimental method based on software defined radio according to claim 1, characterized in that: The experimental system controls temperature and humidity parameters through the environmental monitoring module, and adjusts the temperature and humidity in real time according to environmental factors, so that the fluctuation range of environmental parameters is controlled within ±0.5°C and ±3%RH.

7. The artificial rainfall experimental method based on software defined radio according to claim 1, characterized in that: The step (5) comprises the following steps: The data processing terminal constructs a coupling model of rainfall intensity R, raindrop size distribution D, and channel state information CSI: Where n is the number of raindrops passing through the signal beam per unit time, which is related to the structure of the artificial rainfall sprinkler system; t is the continuous time variable in the model; t n is the precise moment of occurrence of the nth raindrop collision event; A n is the instantaneous signal attenuation caused by the nth raindrop hitting the antenna or propagation path; α is the basic amplitude parameter of the rainfall attenuation coefficient; β is the nonlinear exponential parameter of the rainfall attenuation model; L is the propagation path length of the electromagnetic wave in the rainfall environment, where the raindrop size distribution is It can be calibrated in real time using a laser raindrop spectrometer; the dielectric constant ò(T) = 78.54 [1-0.0046(T-25°C)], where T is the ambient temperature, and can be calculated using temperature data from the environmental control module; the humidity compensation coefficient λ = 0.15, and the model solution uses an adaptive Monte Carlo integration algorithm; The above formula can be used to obtain the functional relationship between rainfall intensity, raindrop size distribution and channel state information. After solving it, the reversible mapping relationship between the above three parameters can be obtained: in: The above formula can be used to obtain the inverse calculation formula of rainfall intensity for practical application.

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