CN-121997958-A - RFID reader-writer implementation method and system based on self-interference cancellation

CN121997958ACN 121997958 ACN121997958 ACN 121997958ACN-121997958-A

Abstract

The invention discloses a self-interference cancellation-based RFID reader-writer implementation method and system, wherein the method comprises the steps that an RFID chip generates radio frequency signals, transmits and couples out reference signals, meanwhile, reflected signals from tags received by an antenna enter a receiving channel, self-interference reconstruction signals with the same amplitude and opposite phase to the self-interference signals are generated by regulating the amplitude and the opposite phase according to the reference signals coupled out by the transmitting channel, the self-interference reconstruction signals and the received signals are subjected to vector synthesis so as to effectively cancel self-interference components, only pure tag reflected signals are reserved after cancellation processing and are coupled into two paths through a second coupler, one path of signals are transmitted back to the RFID chip, the other path of signals enter a feedback link, and the power of residual self-interference signals is obtained in the feedback link to carry out iterative control on the self-interference reconstruction module. The invention effectively suppresses strong self-interference signals leaked from the transmitting channel to the receiving channel, and increases effective communication distance and identification reliability.

Inventors

WANG YAHAO
LI TONG
PAN WENSHENG
HU FU
MA WANZHI
ZHAO HONGZHI
SHEN YING
SHAO SHIHAI

Assignees

电子科技大学

Dates

Publication Date: 20260508
Application Date: 20260128

Claims (5)

1. The method for realizing the RFID reader-writer based on self-interference cancellation is characterized by comprising the following steps of: The method comprises the steps that S1, an RFID chip generates radio frequency signals, the radio frequency signals are divided into two paths in a transmitting channel through a first coupler, one path of the radio frequency signals are transmitted to an antenna for transmitting, and the other path of the radio frequency signals are used as reference signals and coupled to a self-interference reconstruction module; S2, according to the reference signal coupled by the transmitting channel, the self-interference reconstruction module carries out accurate amplitude and phase regulation and control to generate a self-interference reconstruction signal with the same amplitude and opposite phase to the self-interference signal; S3, in a receiving channel, carrying out vector synthesis on the self-interference reconstruction signal and the receiving signal by utilizing an interference cancellation module, so as to effectively cancel the self-interference component, and only reserving a pure tag reflection signal after cancellation processing; Step S4, only the pure tag reflection signals are reserved after the cancellation processing and are coupled into two paths through a second coupler, one path of signals are transmitted back to the RFID chip, and the other path of signals enter a feedback link; And S5, in the feedback link, the power of the residual self-interference signal is obtained through the detector and is sent to the singlechip, and the singlechip carries out iterative control on the self-interference reconstruction module.
2. The method for implementing the RFID reader-writer based on self-interference cancellation of claim 1, wherein the self-interference reconstruction module comprises a first power divider, four channels and a second power divider, and each channel comprises a digital control attenuator and a phase delay unit; The first power divider divides the reference signal into four paths, the four paths are respectively transmitted to four channels, the numerical control attenuator in each channel receives the data of the first power divider to carry out independent amplitude regulation and control, each numerical control attenuator is connected with the second power divider through a phase delay unit in the channel, and the second power divider is used as a combiner and used for vector synthesis of the received signals, so that accurate cancellation signals with the same amplitude and opposite phases with the original interference signals are reconstructed.
3. The method of claim 2, wherein the phase delay units in the four channels are a direct path of a phase reference, a transmission line with a 90 DEG fixed phase shift, a transmission line with a 180 DEG fixed phase shift, and a transmission line with a 270 DEG fixed phase shift.
4. The method for implementing the RFID reader-writer based on self-interference cancellation as claimed in claim 3, wherein in the feedback link, the power of the residual self-interference signal obtained by the detector is sent to the singlechip, and the singlechip performs iterative control on the self-interference reconstruction module, and the method comprises the following steps: S501, initializing to obtain random attenuation values of numerical control attenuators in four channels =[ , , , ], , , , Respectively representing attenuation values of the numerical control attenuators in the first channel to the fourth channel, wherein the attenuation range of the numerical control attenuators is 0-31.5dB, and the attenuation ranges are stepped to 0.5dB; S502 at Is disturbed to obtain a new solution The multistage disturbance scheme is adopted: ; Wherein, the The value range is { -1, -0.5, 0, 0.5, 1}, which is the unit is dB; Is provided with Is Bernoulli random variable, which is a probability The valued variable is 1, which means that the stage disturbance is triggered, otherwise, the variable is 0; Randomly generating a value; To with random probability The additional disturbance of the trigger is that, Is the first The magnitude of the stage disturbance is determined, = And meet when In the time-course of which the first and second contact surfaces, ; S503 for new solution And current solution Defining a power difference: ; According to the Metropolis acceptance criterion of the simulated annealing algorithm, the acceptance probability is: ; Wherein the method comprises the steps of Is a parameter of the current temperature and, Is the bottom of natural logarithm; If the new solution is better, i.e. the power is lower, the new solution is directly accepted, and then updated = ; If the new solution is worse, i.e. the power is higher, probability is given Accepting the new solution, updating after accepting the new solution = To receive new solutions Returning to the step S502 repeatedly, and repeatedly executing the steps S502-S503; s504, every time a new solution is obtained, the temperature is reduced: is the cooling coefficient; until the temperature drops to a temperature threshold: Or the new solution reaches the power threshold Ending the annealing algorithm and outputting the optimal attenuation configuration And locked, the aim of minimizing the residual power is fulfilled, Is obtained in the process of repeatedly executing the steps S502 to S503 Is a minimum of (2).
5. The RFID reader-writer realizing system based on self-interference cancellation is characterized by comprising an RFID chip, a transmitting channel, an antenna, an interference reconstruction module, a receiving channel and a feedback link; the RFID chip is used for generating radio frequency signals and transmitting the radio frequency signals to the transmitting channel; The transmitting channel comprises a first coupler, a self-interference reconstruction module, a receiving channel and a second coupler, wherein the first coupler is used for dividing a radio frequency signal from an RFID chip into two paths, and transmitting one path to the antenna for transmitting; The self-interference reconstruction module is used for carrying out accurate amplitude and phase regulation according to the reference signal coupled by the transmitting channel, and generating a self-interference reconstruction signal with the same amplitude and opposite phase as the self-interference signal; The receiving channel comprises an interference cancellation module and a second coupler, wherein the interference cancellation module utilizes the interference cancellation module to carry out vector synthesis on a self-interference reconstruction signal and a received signal, so that the self-interference component is effectively cancelled, and only pure tag reflection signals are reserved after cancellation processing; The feedback link comprises a detector and a singlechip, the detector acquires the power of the residual self-interference signal through the detector and sends the power to the singlechip, and the singlechip carries out iterative control on the self-interference reconstruction module.

Description

RFID reader-writer implementation method and system based on self-interference cancellation Technical Field The invention relates to the field of radio frequency identification, in particular to a method and a system for realizing an RFID reader based on self-interference cancellation. Background Radio Frequency Identification (RFID) technology, which is a non-contact automatic identification technology, has been widely used in various fields such as retail, logistics, asset management, and industrial internet of things because of its high efficiency, durability, and cost effectiveness. Passive RFID systems are particularly favored because their tags do not require a built-in power supply, and can be activated by the rf energy emitted by the reader, resulting in long life and low maintenance costs. However, the short communication distance is always a core bottleneck that restricts further improvement of the performance of the passive RFID system. In the design of compact RFID readers, a transceiver-integrated single antenna architecture is widely adopted due to its small size and low cost. However, this architecture has an inherent disadvantage in that strong transmit signals leak through the antenna, circulator, etc. paths into sensitive receive channels, creating severe self-interference. Such self-interference signals can significantly reduce the signal-to-noise ratio of the receiver, resulting in a drastic deterioration of the reception sensitivity, thereby limiting the effective communication distance of the reader-writer and the tag identification reliability. The traditional scheme is that if a high-isolation circulator is adopted or out-of-band filtering is added, the isolation is limited, and the system requirement under high transmission power is difficult to meet. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a method and a system for realizing an RFID reader-writer based on self-interference cancellation, which effectively inhibit strong self-interference signals leaking from a transmitting channel to a receiving channel, thereby greatly improving the receiving sensitivity and increasing the effective communication distance and the identification reliability. The invention aims at realizing the following technical scheme that the RFID reader-writer realizing method based on self-interference cancellation comprises the following steps: The method comprises the steps that S1, an RFID chip generates radio frequency signals, the radio frequency signals are divided into two paths in a transmitting channel through a first coupler, one path of the radio frequency signals are transmitted to an antenna for transmitting, and the other path of the radio frequency signals are used as reference signals and coupled to a self-interference reconstruction module; S2, according to the reference signal coupled by the transmitting channel, the self-interference reconstruction module carries out accurate amplitude and phase regulation and control to generate a self-interference reconstruction signal with the same amplitude and opposite phase to the self-interference signal; S3, in a receiving channel, carrying out vector synthesis on the self-interference reconstruction signal and the receiving signal by utilizing an interference cancellation module, so as to effectively cancel the self-interference component, and only reserving a pure tag reflection signal after cancellation processing; Step S4, only the pure tag reflection signals are reserved after the cancellation processing and are coupled into two paths through a second coupler, one path of signals are transmitted back to the RFID chip, and the other path of signals are subjected to feedback links; And S5, in the feedback link, the power of the residual self-interference signal is obtained through the detector and is sent to the singlechip, and the singlechip carries out iterative control on the self-interference reconstruction module. An RFID reader-writer realizing system based on self-interference cancellation comprises an RFID chip, a transmitting channel, an antenna, an interference reconstruction module, a receiving channel and a feedback link; the RFID chip is used for generating radio frequency signals and transmitting the radio frequency signals to the transmitting channel; The transmitting channel comprises a first coupler, a self-interference reconstruction module, a receiving channel and a second coupler, wherein the first coupler is used for dividing a radio frequency signal from an RFID chip into two paths, and transmitting one path to the antenna for transmitting; The self-interference reconstruction module is used for carrying out accurate amplitude and phase regulation according to the reference signal coupled by the transmitting channel, and generating a self-interference reconstruction signal with the same amplitude and opposite phase as the self-interference signal; The receiving channel c