A method, system for providing power to an RFID tag by means of wireless power supply

Abstract

The present application belongs to the field of wireless radio frequency identification technology, and particularly relates to a method and system for providing power to an RFID tag by wireless power supply. The method provides additional energy to an RFID electronic tag by wireless means, and can effectively improve the transmitting power and receiving sensitivity of the RFID electronic tag without significantly increasing the size of the tag or adding a battery, thereby improving the working distance and anti-interference capability of the tag. The method also designs a dynamic adjustment method for the transmitting power of the excitation source, which can dynamically adjust the transmitting power of the excitation source according to the signal strength information and phase information of the tag read by the reader, so that the transmitting power of the tag is always maintained at the optimal state required for reading, and the waste of energy is avoided.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency identification technology, and more specifically, relates to a method and system for providing power to RFID tags via wireless power supply. Background Technology

[0002] Currently, UHF RFID tags are widely used in logistics, warehousing, and other fields to replace traditional barcodes and QR codes. RFID tags can be read in batches over long distances, an advantage that traditional barcodes lack, effectively improving scanning efficiency.

[0003] However, RFID tags are actually passive tags. Their operating energy comes from the energy radiated by the RFID reader. At greater distances or when the tag is obstructed, the energy received and radiated by the tag attenuates significantly, causing the reader to fail to read the tag information and resulting in missed reads. To reduce the probability of missed reads, methods such as increasing the RFID reader's transmission power, increasing antenna gain, or using other tags with better performance are commonly employed. However, increasing antenna gain leads to a larger antenna size, increasing costs. Similarly, significantly improving tag performance also requires a larger tag size, making it unsuitable for use on smaller items, and larger tags also increase costs.

[0004] While using active tags can increase the tag's transmission power, it requires regular battery replacements, which increases workload, leads to larger tag size and higher costs, and is not conducive to applications such as logistics and warehouse management. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, the present invention aims to provide a method and system for supplying power to RFID tags wirelessly. By providing additional energy to RFID electronic tags wirelessly, the transmission power and receiving sensitivity of RFID electronic tags can be improved without significantly increasing tag size or adding batteries, thereby increasing the tag's working distance and anti-interference capability.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] A method for providing power to RFID tags wirelessly includes the following steps:

[0008] (1) After receiving the tag reading instruction, the host computer controls the excitation source to send electromagnetic waves, and at the same time the RFID reader reads the tag information;

[0009] (2) The RFID reader sends the read tag information to the host computer, and the software in the host computer analyzes the tag information, calculates the optimal excitation source transmission power, and sends an instruction to the excitation source to adjust the transmission power of the excitation source according to the calculated optimal excitation source transmission power;

[0010] (3) The host computer determines whether the reading is complete. If the reading is not complete, it returns to step (1). If the reading is complete, it sends an instruction to the excitation source, and the excitation source stops sending electromagnetic waves.

[0011] In step (2), the process of calculating and adjusting the transmission power is as follows:

[0012] (2.1) Under normal operating conditions, collect RSSI data and phase values ​​of RFID tag reflected signals at different transmission powers of the excitation source to form a dataset containing tag ID, excitation source transmission power, signal strength, RFID reader transmission power, RFID signal frequency, and signal phase;

[0013] (2.2) Calculate the distance between the tag and the RFID antenna using the RFID signal frequency and phase;

[0014] The calculation process involves reading tag information at different frequencies during each read operation. and The corresponding wavelengths are respectively and The phase of the received tag reflection signal is and ,in , The relationship between phase and distance is:

[0015] ;

[0016] ;

[0017] Calculate the distance ,in, At the speed of light, ; The phase difference introduced to the reader's transmitting circuit The phase difference introduced to the reader's receiving circuit The phase difference introduced by the characteristics of RFID tags It is a positive integer;

[0018] The calculated distance value is used to filter the received data from the same tag, selecting the data closest to the antenna, i.e., the data with the smallest distance value;

[0019] (2.3) Determine the minimum RSSI value based on tag performance and field testing results. If the signal strength is less than this value, the tag miss rate is >90%;

[0020] (2.4) Construct a neural network to extract features from the filtered dataset in step (2.2) and learn the relationship between the excitation source's emission power and the tag's reflected signal strength RSSI:

[0021] (2.4.1) Based on the distribution of RSSI values, predict the excitation source transmission power and obtain its loss value compared with the actual excitation source transmission power;

[0022] ;

[0023] in, The excitation source transmit power predicted by RSSI, The current transmit power of the excitation source;

[0024] The Adam optimizer is used to optimize network parameters, making... Minimum, get Mapping relationship with RSSI ;

[0025] (2.4.2) Based on the prediction results of the neural network, a genetic algorithm is used to search for the global optimum under constraints. Values ​​predicted using neural networks The value is used as a gene to predict the RSSI value. Constraints are incorporated into the fitness calculation through a penalty function, where fitness... , The penalty coefficient is determined by the deviation between the predicted RSSI value and the actual RSSI value. The larger the deviation, the larger the penalty coefficient. The transmit power is then obtained through a genetic algorithm. global optimal solution _opt;

[0026] (2.5) The host computer software sends a command to the excitation source to set its power to... _opt. Get The RSSI values ​​of all tag reflection signals read under _opt power are calculated, and the average RSSI value is obtained. During subsequent readings, the excitation source's transmit power is fine-tuned based on this, ensuring that the overall RSSI value obtained each time is close to the optimal RSSI value. The average deviation is less than the threshold. ,Right now , The value is determined based on the actual scenario;

[0027] According to the formula—

[0028] ;

[0029] in, For the number of tags, For the first Each tag value;

[0030] like , If so, the power remains unchanged;

[0031] like , , Then the power decreases. Then the power increases;

[0032] like , , Then the power decreases. Then the power increases;

[0033] in, This is the adjusted power value. The power value before adjustment. , The power adjustment threshold is determined based on actual testing.

[0034] Furthermore, in step (2.1), a label can be read repeatedly to obtain multiple data entries corresponding to a label.

[0035] Further, in step (2.4.2), the constraint condition is: , ,in The maximum transmission power of the excitation source is determined by the hardware design of the excitation source. During operation, the transmission power of the excitation source is less than this maximum transmission power. This is the minimum allowed value for RSSI; if the value is less than this, the tag may not be readable. The on-site testing was conducted based on the environment, RFID reader transmission power, and tag performance.

[0036] Furthermore, the adjustment step size of the transmission power of the excitation source is a minimum of 1dBm and a maximum of 3dBm.

[0037] A method for adjusting the transmission power of an excitation source includes the following steps:

[0038] (1) Under normal operating conditions, collect RSSI data and phase values ​​of RFID tag reflected signals at different transmission powers of the excitation source to form a dataset containing tag ID, transmission power, signal strength, RFID reader transmission power, RFID signal frequency, and signal phase;

[0039] (2) Calculate the distance between the tag and the RFID antenna by using the RFID signal frequency and signal phase;

[0040] The calculation process involves reading tag information at different frequencies during each read operation. and The corresponding wavelengths are respectively and The phase of the received tag reflection signal is and ,in , The relationship between phase and distance is:

[0041] ;

[0042] ;

[0043] Calculate the distance ,in, At the speed of light, ; The phase difference introduced to the reader's transmitting circuit The phase difference introduced to the reader's receiving circuit The phase difference introduced by the characteristics of RFID tags It is a positive integer;

[0044] The calculated distance value is used to filter the received data from the same tag, selecting the data closest to the antenna, i.e., the data with the smallest distance value;

[0045] (3) Determine the minimum RSSI value based on the tag performance and on-site testing results. If the signal strength is less than this value, the tag miss rate is >90%;

[0046] (4) Construct a neural network to extract features from the filtered dataset in step (2.2) and learn the relationship between the excitation source emission power and the tag reflected signal strength RSSI:

[0047] (4.1) Based on the distribution of RSSI values, predict the excitation source transmission power and obtain its loss value compared with the actual excitation source transmission power;

[0048] ;

[0049] in, The excitation source transmit power predicted by RSSI, The current transmit power of the excitation source;

[0050] The Adam optimizer is used to optimize network parameters, making... Minimum, get Mapping relationship with RSSI ;

[0051] (4.2) Based on the prediction results of the neural network, a genetic algorithm is used to search for the global optimum under constraints. Values ​​predicted using neural networks The value is used as a gene to predict the RSSI value. Constraints are incorporated into the fitness calculation through a penalty function, where fitness... , The penalty coefficient is determined by the deviation between the predicted RSSI value and the actual RSSI value. The larger the deviation, the larger the penalty coefficient. The transmit power is then obtained through a genetic algorithm. global optimal solution _opt;

[0052] (5) The host computer software sends a command to the excitation source to set its power to _opt. Get The RSSI values ​​of all tag reflection signals read under _opt power are calculated, and the average RSSI value is obtained. During subsequent readings, the excitation source's transmit power is fine-tuned based on this, ensuring that the overall RSSI value obtained each time is close to the optimal RSSI value. The average deviation is less than the threshold. ,Right now , The value is determined based on the actual scenario;

[0053] According to the formula—

[0054] ;

[0055] in, For the number of tags, For the first Each tag value;

[0056] like , If so, the power remains unchanged;

[0057] like , , Then the power decreases. Then the power increases;

[0058] like , , Then the power decreases. Then the power increases;

[0059] in, This is the adjusted power value. The power value before adjustment. , The power adjustment threshold is determined based on actual testing. After adjustment, the host computer software will set the excitation source power to... .

[0060] A system based on the above method, the system comprising an electronic tag module, an RFID reader module, an excitation source module, and a host computer module;

[0061] The electronic tag module includes an RFID antenna and an energy harvesting antenna;

[0062] The RFID reader module includes a reader antenna, the excitation source module includes an excitation source antenna, and the host computer is communicatively connected to both the RFID reader module and the excitation source module.

[0063] The reader sends a reading command to the RFID tag via its antenna to read the RFID tag information.

[0064] The excitation source antenna uses an ISM band 5.8GHz signal to transmit a continuous electromagnetic wave signal of 5.8GHz to the electronic tag module.

[0065] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0066] This method provides additional power to RFID tags wirelessly, effectively improving the transmission power and reception sensitivity of RFID tags without significantly increasing tag size or adding batteries, thereby increasing the tag's working distance and anti-interference capability.

[0067] This method also includes a dynamic adjustment mechanism for the excitation source's transmission power. Based on the tag signal strength and phase information read by the reader, the excitation source's transmission power can be dynamically adjusted to ensure that the tag's transmission power is always kept in the optimal state that meets the reading requirements, thus avoiding energy waste. Attached Figure Description

[0068] Figure 1 This is a schematic flowchart illustrating the steps of the method described in this invention;

[0069] Figure 2 This is a schematic diagram of the module structure of the system described in this invention; Detailed Implementation

[0070] The present invention will be further described below with reference to specific embodiments.

[0071] like Figure 1 As shown, the method for providing power to RFID tags via wireless power supply according to the present invention includes the following steps:

[0072] (1) After the host computer receives the tag reading instruction sent by the client server, it controls the excitation source to send electromagnetic wave signals to provide energy to the electronic tag, and at the same time controls the RFID reader to start reading RFID tag information;

[0073] (2) The RFID reader sends the read tag information to the host computer, the software in the host computer analyzes the tag information, calculates the optimal excitation source transmission power, and the host computer sends a command to the excitation source to adjust the excitation source transmission power;

[0074] In this embodiment, the excitation source emits a 5.8GHz radio frequency signal to power the electronic tag. To conserve energy and extend the device's lifespan, the transmission power should be minimized while ensuring the tag can be read correctly. The RFID reader can acquire the electronic tag's signal strength (RSSI value) and phase information. A lower RSSI value indicates a lower reflected signal strength. By analyzing the feedback RSSI value, it can be determined whether the current transmission power is too high or too low. A low RSSI value indicates a risk of the tag not being readable, requiring an increase in the excitation source's transmission power. When all tags can be read, excessively high excitation source transmission power can lead to energy waste or interference caused by surrounding tags being read. In practical use, factors such as the electronic tag's pasting direction, position, distance from the RFID reader, differences in the electronic tag's performance, and multipath effects can all affect the RSSI value, leading to inaccurate feedback information. Therefore, phase information is introduced. Phase information can reflect changes in the electronic tag's position or the tag's signal reflection path. Ideally, if the tag's position or the reflected signal path remains unchanged, the phase information will also remain unchanged. By combining these parameters, we can assess whether the current excitation source's transmit power is optimal. The purpose of power adjustment is to obtain an ideal RSSI value at a lower excitation source transmit power, thereby ensuring that the tag is read completely and achieving the lowest possible missed read rate.

[0075] Therefore, the process of calculating and adjusting the transmission power described in this invention is as follows:

[0076] (2.1) Under normal operating conditions, collect RSSI data and phase values ​​of RFID tag reflected signals at different transmission powers of the excitation source, and form a dataset {[TagID_1, TxPower_1, RSSI_1, RFID_Tx_Power_1, RFID_Freq_1, RFID_Phase_1]}...{[TagID_N, TxPower_N, RSSI_N, RFID_Tx_Power_N, RFID_Freq_N, RFID_Phase_N]} containing tag ID (TagID), transmission power (TxPower), signal strength (RSSI), RFID reader transmission power (RFIS_Tx_Power), RFID signal frequency (RFID_Freq), and signal phase (RFID_Phase).

[0077] During the reading process, a label can be read repeatedly, thus obtaining multiple data entries corresponding to a single label.

[0078] (2.2) Due to the reflection of the surrounding environment, the tag path may change, or the tag may be in a moving state, and the phase of the reflected signal may change. The RSSI of multiple data of the same tag may change. Therefore, the distance between the tag and the RFID antenna can be calculated by the RFID signal frequency and signal phase.

[0079] The calculation process involves reading tag information at different frequencies during each read operation. and The corresponding wavelengths are respectively and The phase of the received tag reflection signal is and ,in , The relationship between phase and distance is:

[0080] ;

[0081] ;

[0082] Calculate the distance ,in, At the speed of light, ; The phase difference introduced to the reader's transmitting circuit The phase difference introduced to the reader's receiving circuit The phase difference introduced by the characteristics of RFID tags It is a positive integer;

[0083] The calculated distance value is used to filter the received data from the same tag, selecting the data closest to the antenna, i.e., the data with the smallest distance value, thereby reducing the amount of data.

[0084] (2.3) Determine the minimum RSSI value based on tag performance and field testing results. If the signal strength is less than this value (min), the tag's missed read rate is >90%.

[0085] (2.4) Construct a neural network to extract features from the filtered dataset in step (2.2) and learn the relationship between the excitation source's emission power and the tag's reflected signal strength RSSI:

[0086] (2.4.1) Based on the distribution of RSSI values, predict the excitation source transmission power and obtain its loss value compared with the actual excitation source transmission power;

[0087] ;

[0088] in, The excitation source transmit power predicted by RSSI, The current transmit power of the excitation source;

[0089] The Adam optimizer is used to optimize network parameters, making... Minimum, get Mapping relationship with RSSI ;

[0090] (2.4.2) Based on the prediction results of the neural network, a genetic algorithm is used to search for the global optimum under constraints. Values ​​predicted using neural networks The value is used as a gene to predict the RSSI value. Constraints are incorporated into the fitness calculation through a penalty function, where fitness... , The penalty coefficient is determined by the deviation between the predicted RSSI value and the actual RSSI value. The larger the deviation, the larger the penalty coefficient. The transmit power is then obtained through a genetic algorithm. global optimal solution _opt;

[0091] The constraints are , ,in The maximum transmission power of the excitation source is determined by the hardware design of the excitation source. During operation, the transmission power of the excitation source is less than this maximum transmission power. This is the minimum allowed value for RSSI; if the value is less than this, the tag may not be readable. The on-site testing was conducted based on the environment, RFID reader transmission power, and tag performance.

[0092] (2.5) The host computer software sends a command to the excitation source to set its power to... _opt. Get The RSSI values ​​of all tag reflection signals read under _opt power are calculated, and the average RSSI value is obtained. During subsequent readings, the excitation source's transmission power is fine-tuned to ensure that the overall RSSI value distribution obtained each time is close to the optimal value, thus aligning the overall RSSI value with the optimal RSSI value. The average deviation is less than the threshold. ,Right now , The value is determined based on the actual scenario;

[0093] The adjustment step size of the excitation source's transmission power is a minimum of 1dBm and a maximum of 3dBm.

[0094] According to the formula—

[0095] ;

[0096] in, For the number of tags, For the first Each tag value;

[0097] like , If so, the power remains unchanged;

[0098] like , , Then the power decreases. Then the power increases;

[0099] like , , Then the power decreases. Then the power increases;

[0100] in, This is the adjusted power value. The power value before adjustment. , The power adjustment threshold is determined based on actual testing. After adjustment, the host computer software will set the excitation source power to... .

[0101] By using the optimal excitation source power Based on _opt, further fine-tuning of the excitation source's transmission power allows for rapid tag reading. Through testing and learning from RFID tags on multiple batches of goods, the optimal transmission power of the excitation source is determined. This optimal transmission power can then be used to provide energy to the tags for normal reading. The system will readjust the excitation source's transmission power when tag performance changes significantly or the on-site environment changes. The excitation source and RFID reader are separate units, working synchronously without interference, thus improving reading efficiency.

[0102] In the above technical solution, an RFID electronic tag capable of collecting electromagnetic wave energy from the space environment is used, simultaneously obtaining energy from space and the RFID reader, ensuring the stability of the energy supply. Through a dedicated excitation source, electromagnetic wave signals are radiated wirelessly to the RFID electronic tag. This solution uses a 5.8GHz signal in the ISM band to continuously radiate 5.8GHz electromagnetic wave signals to the RFID electronic tag, providing the energy required for tag operation. Since the UHF RFID operating frequency band is 840~960MHz, and the excitation source operates at 5.8GHz, there is no impact.

[0103] In this solution, the host computer runs control software to coordinate the RFID reader and the excitation source. Based on the data information such as the tag signal strength and phase read by the reader, the transmission power of the excitation source is dynamically adjusted so that the tag transmission power is always kept in the optimal state to meet the reading requirements, thus avoiding energy waste.

[0104] like Figure 2 As shown, based on the above method, the system to which the method of the present invention is applied includes an electronic tag module, an RFID reader module, an excitation source module, and a host computer module;

[0105] The electronic tag module includes an RFID antenna and an energy harvesting antenna;

[0106] The RFID reader module includes a reader antenna, the excitation source module includes an excitation source antenna, and the host computer communicates with both the RFID reader module and the excitation source module.

[0107] The reader antenna sends RFID commands to the RFID antenna to read RFID tag information;

[0108] The excitation source antenna uses the ISM band 5.8GHz signal to transmit a continuous electromagnetic wave signal of 5.8GHz to the electronic tag module.

Claims

1. A method of providing power to an RFID tag by means of wireless power supply, characterized in that, The method comprises the following steps: (1) after obtaining the label reading instruction, the upper computer controls the excitation source to send electromagnetic waves, and the RFID reader reads the label information; (2) the RFID reader sends the read label information to the upper computer, the software in the upper computer analyzes the label information, calculates the optimal excitation source transmission power, and according to the calculated optimal excitation source transmission power, the upper computer sends instructions to the excitation source to adjust the transmission power of the excitation source; (3) the upper computer judges whether the reading is completed, if not, it returns to step (1), if yes, it sends instructions to the excitation source to stop sending electromagnetic waves; In step (2), the process of calculating and adjusting the transmission power is as follows: (2.1) in the normal working state, the RSSI data and phase value of the RFID tag reflection signal of the excitation source under different transmission powers are collected to form a data set containing label ID, transmission power, signal strength, RFID reader transmission power, RFID signal frequency and signal phase; (2.2) the distance of the tag from the RFID antenna is calculated through the RFID signal frequency and the phase value of the tag reflection signal; The process of calculation is that the RFID reader reads the tag information by using different frequencies respectively at each reading, which are and , the corresponding wavelengths are and , the received tag reflection signal phases are and , wherein , , and the phase-distance relationship is: ； ； The distance is calculated wherein c is the speed of light, ; is a phase difference introduced by the reader transmit circuit, is a phase difference introduced by the reader receive circuit, is a phase difference introduced by the RFID tag characteristics, is a positive integer; Through the calculated distance value, the data of the same tag received in step (2.1) are filtered, and the data closest to the antenna, i.e. the data with the smallest distance value, are selected; (2.3) According to the tag performance and the field test, determine the minimum RSSI value (RSSImin) , if the signal strength is less than this value, the tag miss reading rate > 90%; (2.4) a neural network is constructed, the features of the filtered data set in step (2.2) are extracted, and the relationship between the excitation source transmission power and the label reflection signal RSSI is learned: (2.4.1) according to the distribution of the RSSI value, the excitation source transmission power is predicted, and the loss value of the predicted excitation source transmission power and the actual excitation source transmission power is obtained; ； wherein, is the excitation source transmit power predicted by RSSI, is the excitation source current transmit power; The network parameters are optimized using an Adam optimizer, so that the minimum is obtained the mapping relationship between the RSSI ; (2.4.2) Based on the prediction results of the neural network, a genetic algorithm is used to search for the global optimum under constraints. Values ​​predicted using neural networks The value is used as a gene to predict the RSSI value. Constraints are incorporated into the fitness calculation through a penalty function, where fitness... , The penalty coefficient is determined by the deviation between the predicted RSSI value and the actual RSSI value. The larger the deviation, the larger the penalty coefficient. The transmit power is then obtained through a genetic algorithm. global optimal solution _opt; (2.5) The host computer software sends instructions to the excitation source to set its power to the value obtained in step (2.4.2) _opt, and obtains _opt, and calculates the average RSSI value of all the tag reflection signals read at this power, i.e. the average optimal , and subsequently adjusts the excitation source transmission power based on this, so that the overall RSSI value distribution is located near the optimal value , i.e. the average deviation of the overall RSSI value from the optimal value is less than a threshold , i.e. , The value of the threshold is determined according to the actual scene. According to the formula: ； wherein, is the number of tags, is the value of the th tag, value of the th tag. If , , the power is constant; If , , then the power is reduced, then the power is increased; If , , then the power is reduced, then the power is increased; Wherein, is the adjusted power value, is the power value before adjustment, , is the power adjustment threshold value, determined according to actual test, after adjustment, the host computer software will set the excitation source power to .

2. The method of supplying power to an RFID tag by wireless power feeding according to Claim 1, wherein In step (2.1), a tag can be repeatedly read multiple times to obtain multiple data corresponding to a tag.

3. The method of providing power to an RFID tag by wireless power supply according to claim 1, wherein In step (2.4.2), the constraint condition is , wherein is the maximum transmitting power of the excitation source, determined by the hardware design of the excitation source, and the transmitting power of the excitation source in operation is less than the maximum transmitting power; is the minimum value allowed for RSSI.

4. The method of supplying power to an RFID tag by wireless power feeding according to Claim 1, wherein The adjustment step of the transmission power of the excitation source is 1dBm at least and 3dBm at most.

5. A method of adjusting the emission power of an excitation source, characterized in that The method comprises the following steps: (1) in the normal working state, the RSSI data and phase value of the RFID tag reflection signal of the excitation source under different transmission powers are collected to form a data set containing label ID, excitation source transmission power, signal strength, RFID reader transmission power, RFID signal frequency and signal phase; (2) the distance of the tag from the RFID antenna is calculated through the RFID signal frequency and the phase value of the signal; The process of calculation is that, at each reading, the tag information is read with two different frequencies respectively, which are and , the corresponding wavelengths are and , the received tag reflection signal phases are and , wherein , , and the phase-distance relationship is: ； ； The distance is calculated wherein, c is the speed of light, ; is a phase difference introduced by the reader transmit circuit, is a phase difference introduced by the reader receive circuit, is a phase difference introduced by the RFID tag characteristics, is a positive integer; Through the calculated distance value, the data of the same tag received are filtered, and the data closest to the antenna, i.e. the data with the smallest distance value, are selected; (3) According to the tag performance and the on-site test, the minimum RSSI value is determined (0 ), if the signal strength is less than the value, the tag miss reading rate is > 90%; (4) a neural network is constructed, the features of the filtered data set in step (2.2) are extracted, and the relationship between the excitation source transmission power and the label reflection signal strength RSSI is learned: (4.1) according to the distribution of the RSSI value, the excitation source transmission power is predicted, and the loss value of the predicted excitation source transmission power and the actual excitation source transmission power is obtained; ； wherein, is the excitation source transmit power predicted by RSSI, is the excitation source current transmit power; The network parameters are optimized using an Adam optimizer, so that the minimum is obtained the mapping relationship between the RSSI ; (4.2) Based on the prediction results of the neural network, a genetic algorithm is used to search for the global optimum under constraints. Values ​​predicted using neural networks The value is used as a gene to predict the RSSI value. Constraints are incorporated into the fitness calculation through a penalty function, where fitness... , The penalty coefficient is determined by the deviation between the predicted RSSI value and the actual RSSI value. The larger the deviation, the larger the penalty coefficient. The transmit power is then obtained through a genetic algorithm. global optimal solution _opt; (5) The host computer software sends instructions to the excitation source to set its power to _opt, acquires _the RSSI values of all tag reflection signals read at this power, and calculates the average RSSI value, i.e. the average optimal , and subsequently reads, on this basis, fine-tunes the excitation source transmission power so that the overall RSSI value has an average deviation from the optimal RSSI value of less than a threshold value , i.e. , The value of the threshold is determined according to the actual scene. According to the formula: ； wherein, is the number of tags, is the value of the th tag, th tag. If , , the power is constant; If , , then the power is reduced, then the power is increased; If , , then the power is reduced, then the power is increased; Wherein, is the adjusted power value, is the power value before adjustment, , is the power adjustment threshold value, determined according to actual test, after adjustment, the host computer software will set the excitation source power to .

6. A system for applying the method according to any one of claims 1-4, characterized in that, The system comprises an electronic tag module, an RFID reader module, an excitation source module and an upper computer module; The electronic tag module comprises an RFID antenna and an energy collection antenna; The RFID reader module comprises a reader antenna, the excitation source module comprises an excitation source antenna, and the upper computer is in communication connection with the RFID reader module and the excitation source module; The reader sends a reading instruction to the RFID tag through the reader antenna, and reads the RFID tag information; The excitation source antenna adopts an ISM frequency band 5.8 GHz signal, and emits a 5.8 GHz continuous electromagnetic wave signal to the electronic tag module.

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