Anti-collision tag chip for room division monitoring and monitoring system comprising the same

Abstract

The application discloses a kind of anti-collision tag chips for room division monitoring and monitoring system comprising it.The anti-collision tag chip includes radio frequency front end, controllable rectifier, super capacitor, digital baseband module and backscatter modulation module, wherein the digital baseband is used to convert data in the chip into a modulated signal, send the modulated signal to the backscatter modulation module, and control the capacitor to send only once within a limited time to avoid continuous sending.The backscatter modulation module is used to convert the modulated signal into a waveform signal, modulate it onto the carrier signal source emitted by the gateway, and send information to the receiving system through backscatter mode.The application solves the problem of anti-collision of pure random tags without memory function for the previous work in each work of the tag chip under the condition of non-real-time, energy harvesting tag chip and duty cycle of charging and working of radio frequency energy in the room division monitoring scenario.

Description

Technical Field

[0001] This invention belongs to the field of indoor distributed antenna system (DAS) monitoring and specifically relates to an anti-collision tag chip for indoor DAS monitoring and a monitoring system containing the same. Background Technology

[0002] An indoor distributed antenna monitoring system is a system used to enhance indoor wireless signal coverage. It works by connecting a large signal source to multiple indoor distributed antennas, thereby evenly distributing the wireless signal throughout the room. The indoor monitoring system uses RFID (Radio Frequency Identification) tags to monitor the operation of the links and antennas. The RFID tags communicate with the indoor distributed antennas. The antennas emit radio frequency signals and receive signals transmitted back from the tags. By analyzing the received signals, the system can determine the location and status of the tags.

[0003] However, due to the low sensitivity of RFID tags and the limited sensitivity of RFID receivers, RFID in indoor distributed monitoring systems cannot effectively monitor line losses. In this situation, tag chips based on radio frequency energy harvesting, with their advantages such as large supercapacitor capacity and time-sharing charging and communication, can achieve higher chip sensitivity and better signal modulation, which also greatly improves receiver sensitivity. However, the time-sharing charging and communication also leads to non-real-time operation of the chip and simplex communication issues, which also pose challenges to receiver collision avoidance.

[0004] In RFID (Radio Frequency Identification) systems, commonly used anti-collision methods include random access protocols based on the Aloha algorithm and time-division multiple access protocols based on time slots. The main reason why RFID anti-collision methods cannot be applied to radio frequency energy harvesting tag chips in indoor distributed monitoring systems is as follows:

[0005] Non-real-time operation: RF energy harvesting tag chips operate in a time-sharing manner between charging and communication, meaning communication is impossible during charging. Traditional anti-collision methods typically employ real-time communication, requiring the tag to interact with the reader instantly. This presents a challenge for RF energy harvesting tag chips in implementing anti-collision functionality.

[0006] Simplex Communication: RF energy harvesting tag chips typically operate in simplex mode, meaning they can only communicate in one direction. However, traditional anti-collision methods often require bidirectional communication between the tag and the reader to achieve better collision detection and conflict resolution. Due to the simplex communication limitation of RF energy harvesting tag chips, and secondly, in areas with high energy density, tag transmission frequencies are higher, crowding out the transmission of low-frequency tags, resulting in the inability to identify low-frequency tags in areas with lower energy density. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing an anti-collision tag chip for indoor distributed monitoring and a monitoring system incorporating the same.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: an anti-collision tag chip for indoor distributed monitoring, comprising a radio frequency front-end, a controllable rectifier, a supercapacitor, a digital baseband module, and a backscatter modulation module;

[0009] The radio frequency front end is used to convert the collected radio frequency energy into electrical energy and deliver it to the controllable rectifier;

[0010] The controllable rectifier is used to determine the voltage magnitude of the radio frequency AC signal, reduce the current of the high voltage output, and convert the AC signal into DC voltage to charge the supercapacitor.

[0011] The digital baseband is used to convert the data in the chip into a modulation signal, send the modulation signal to the backscatter modulation module, and control the capacitor to send only once within a limited time to avoid continuous transmission.

[0012] The reflection-scattering modulation module is used to convert the modulation signal into a waveform signal, modulate it onto the carrier signal source emitted by the gateway, and send the information to the receiving system through backscattering.

[0013] Furthermore, the radio frequency front end includes an antenna and an impedance matching unit; the antenna is used to collect external radio frequency signals and convert them into current, which is then transmitted to the controllable rectifier; the impedance matching unit is used to convert the high impedance of the antenna into the low impedance required by the controllable rectifier.

[0014] Furthermore, the variable rectifier includes a voltage comparator, a multi-stage cascaded rectifier, and a PWM control module;

[0015] The voltage comparator is used to compare the magnitude of the voltage input to the variable rectifier, and is divided into low input case and high input case according to the threshold.

[0016] The multi-stage cascaded rectifier includes two or more rectifiers. Under low input conditions, the switch is turned on, and all rectifiers are cascaded and output. Under high input conditions, the switch is turned off, and the current passes through the first-stage rectifier and enters the PWM control module. The PWM control module controls and adjusts the internal switching frequency and duty cycle to keep the on-state duty cycle at its lowest, thereby reducing the current output.

[0017] Furthermore, the number of rectifiers in a multi-stage cascaded rectifier ranges from 2 to 10.

[0018] Furthermore, a counter and a timer counter are installed within the digital baseband.

[0019] Furthermore, the digital baseband control capacitor transmits data only once within a limited time to avoid continuous transmission. The following steps are adopted: After the digital baseband is started, each completed data transmission is converted into a modulation signal, which increments the counter value by 1. When the count is greater than or equal to 1, the timer counter is triggered to work.

[0020] The timer's operating time is set to T seconds. After the timer expires, the digital baseband will restart data conversion if the supercapacitor is charged, or wait for the supercapacitor to be fully charged before restarting.

[0021] Furthermore, the tag chip also includes an energy management circuit, used to determine and control the charging and discharging state of the supercapacitor and control the operating state of other modules.

[0022] An indoor distributed monitoring system includes: a gateway and the aforementioned anti-collision tag chip; the gateway is used to emit a carrier signal, receive a modulation signal emitted by the tag chip, interact with an external network, and transmit data to a target terminal.

[0023] Furthermore, the gateway sends out carrier signals by gradually decreasing or increasing the power, between the full power Y and the minimum threshold power X, by gradually decreasing or increasing the power in steps of (YX) / n.

[0024] Furthermore, the gateway includes indoor distributed antennas connected to its trunk.

[0025] The existing technology has the following drawbacks:

[0026] 1. The anti-collision scheme for radio frequency energy harvesting tags in indoor distributed monitoring cannot achieve anti-collision detection of tags when the chip is not in real time or when there is a duty cycle between chip charging and operation.

[0027] 2. In areas with high energy density, the tag transmission frequency is high, crowding out low-frequency tags and making it impossible to identify low-frequency tags in areas with lower energy density;

[0028] 3. The plaintext lighting solution requires the chip and gateway to correspond one-to-one during installation, which results in a high error rate, a cumbersome process, and high costs.

[0029] 4. Traditional indoor distributed antenna monitoring based on RFID tags has low sensitivity and can only monitor low line loss due to its real-time requirement.

[0030] 5. Radio frequency energy harvesting-based tag chips, due to the requirement of high sensitivity, separate charging and communication; thus, the chips are difficult to achieve real-time power supply and full-duplex communication.

[0031] The technical problem solved by this application is:

[0032] 1. Solve the collision prevention problem in indoor distributed monitoring scenarios where the radio frequency energy harvesting tag chip is not real-time and there is a duty cycle between chip charging and operation, resulting in purely random tags with no memory function for the previous operation each time the tag chip works;

[0033] 2. By using a variable rectifier, the high RF energy input is rectified with both efficiency and PMW limitations, reducing the tag transmission frequency; by utilizing the internal delay of the digital baseband, the situation of multiple consecutive transmissions after a single charge is avoided, solving the problem of identifying low-frequency communication tags with higher line loss in indoor distributed monitoring scenarios where the line loss is relatively small and the tag transmission frequency is high.

[0034] 3. By utilizing the charging carrier step modulation of the gateway, the charging randomness of the tag chip is enhanced, solving the problem of random collisions when the chip cannot communicate bidirectionally and autonomously sends tag signals. Attached Figure Description

[0035] Figure 1 This is a framework diagram of an indoor distributed monitoring system as an example.

[0036] Figure 2 This is a schematic diagram of a variable rectifier in an embodiment.

[0037] Figure 3 This is a flowchart of the gateway polling process in an embodiment. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0039] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product or device.

[0040] like Figure 1 The indoor distributed monitoring system shown includes a gateway and its trunk-connected indoor antennas, as well as radio frequency energy harvesting tag chips.

[0041] The radio frequency energy harvesting tag chip consists of a radio frequency front-end, a controllable rectifier, a supercapacitor, an energy management module, a digital baseband module, and a backscatter modulation module.

[0042] The radio frequency (RF) front-end, controllable rectifier, supercapacitor, and energy management module are connected in sequence. The RF front-end converts the collected RF energy into electrical energy and supplies it to the controllable rectifier. The controllable rectifier converts the RF AC signal into a DC signal to charge the supercapacitor. The energy management circuit is responsible for judging and controlling the charging and discharging state of the supercapacitor and controlling the working state of other modules. The digital baseband is used to generate a modulation signal and transmit the modulation signal to the backscatter modulation module. The backscatter modulation module is used to modulate the signal into a waveform and transmit it to the gateway. The gateway and its trunk-connected indoor distributed antenna are responsible for emitting energy through the gateway and radiating RF energy after passing through the indoor distributed antenna to provide a carrier wave for the tag chip. At the same time, the indoor distributed antenna connected to the trunk receives the modulation signal emitted by the chip.

[0043] The radio frequency (RF) front end includes an antenna and an impedance matching unit. The antenna collects external RF signals and converts them into current, which is then passed to the rectifier voltage multiplier circuit. The impedance matching unit converts the high impedance of the antenna into the low impedance required by the rectifier voltage multiplier circuit, thereby maximizing energy transfer efficiency.

[0044] The controllable rectifier converts the high-frequency AC signal from the antenna into DC voltage to extract energy from the radio frequency signal. The voltage multiplier enables the output DC voltage to meet the charging needs of subsequent circuits and supercapacitors.

[0045] The variable rectifier is a multi-stage adaptive rectifier, including a voltage comparator, multiple cascaded rectifiers, and a PWM control module. The voltage comparator compares the input magnitude to the variable rectifier, classifying it into low-input and high-input cases based on a threshold. In the low-input case, power cascading technology improves the rectifier's efficiency. By connecting multiple low-dropout rectifier stages in series, the difference between the input and output voltages is reduced, improving the rectifier's transmission efficiency. In the high-input case, the rectifier autonomously selects the output of the rectifier in the lower cascaded state and enters PWM control. A PWM (Pulse Width Modulation) control strategy is used to adjust the switching frequency and duty cycle, reducing the variable rectifier output.

[0046] Energy management module: Used to manage and store the collected energy to ensure the normal operation of the tag chip.

[0047] The backscatter modulation module is used to modulate the digital signal transmitted from the baseband to generate an ASK or FSK modulated signal, which is then modulated onto the carrier signal source emitted by the gateway and sent to the receiving system through backscattering.

[0048] Digital baseband module: Used to read information from the storage module and generate corresponding modulation signals. By reading data from the storage module, it converts it into a modulation signal suitable for transmission, preparing for subsequent signal transmission. After each modulation is completed, a count is performed. If the count is greater than 1, a delay function is entered, and modulation and transmission are stopped to avoid multiple modulations from a single charge. If the capacitor does not provide continuous power during the delay function, the digital baseband is powered off, and the count starts from 0, thus avoiding continuous transmission caused by continuous power supply.

[0049] The gateway and its trunk-connected indoor antennas are responsible for transmitting carrier signals through the gateway and receiving modulation signals from the chip through the trunk-connected indoor antennas; collecting and processing data from the backscatter modulation module and interacting with the external network; receiving and processing data from the backscatter modulation module, communicating and exchanging data with the external network, and transmitting data to the target terminal.

[0050] In another embodiment, the gateway reduces carrier energy in small steps, gradually decreasing or increasing the power in steps of (YX) / n between full power Y and minimum threshold power X. One cycle consists of decreasing the power to the minimum threshold power X and then increasing it back to full power. In multiple cycles, the tag chip receives charging energy with varying power levels, increasing the randomness of the modulated signal transmitted by the tag chip, thereby completing the polling of the entire tag chip group. The gateway's full power is set to Y, the gateway's minimum power threshold to X, the number of steps to n, and the reception time to T. The steps are as follows:

[0051] 1. The gateway transmits carrier signals at full power;

[0052] 2. Within the set time T, the gateway receives and records the received tag IDs;

[0053] 3. The gateway reduces its power in (YX) / n steps, and its transmit power is Y. i The gateway receives and records the tag IDs received within time T;

[0054] 4. When the gateway transmit power Y i Once the power threshold X is reached, the gateway increases the power in steps of (YX) / n. The gateway accepts and records the tag IDs received within time T.

[0055] 5. When Y i When the value equals Y, a complete polling cycle of the gateway ends, and all received ID tags are calculated.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An anti-collision tag chip for room division monitoring, characterized by: The radio frequency front end, the controllable rectifier, the super capacitor, the digital baseband module and the backscatter modulation module are included. The radio frequency front end is used for converting the collected radio frequency energy into electric energy and delivering the electric energy to the controllable rectifier. The controllable rectifier is used for judging the voltage of the radio frequency alternating current signal, reducing the current of the high voltage and outputting, and converting the alternating current signal into direct current voltage to charge the super capacitor. The digital baseband module is used for converting the data in the chip into a modulation signal, sending the modulation signal to the backscatter modulation module, and controlling the capacitor to send only once within a limited time to avoid continuous sending. The backscatter modulation module is used for converting the modulation signal into a waveform signal, modulating the waveform signal onto the carrier signal emitted by the gateway, and sending the information to the gateway through the backscatter mode. The gateway and the room distribution antenna connected with the gateway are responsible for emitting energy through the gateway, radiating radio frequency energy after passing through the room distribution antenna, and providing the carrier for the tag chip, and receiving the modulation signal emitted by the tag chip through the room distribution antenna connected with the gateway. The controllable rectifier includes a voltage comparator, a multi-stage cascaded rectifier and a PWM control module. The voltage comparator is used for comparing the voltage of the input controllable rectifier, and dividing the voltage into low input and high input according to the threshold value. The multi-stage cascaded rectifier includes two or more stages of rectifiers, in the low input condition, the switch is turned on, and all the rectifiers are cascaded to output, in the high input condition, the switch is turned off, the current passes through the first stage of rectifiers to output, and enters the PWM control module, the PWM control module controls the duty cycle of the output, and makes the on-duty cycle in the lowest state, so that the current output is reduced. The digital baseband module is provided with a counter and a timing counter. The digital baseband module controls the capacitor to send only once within a limited time to avoid continuous sending by the following steps: After the digital baseband module is started, the counter value is increased by 1 after each data conversion into a modulation signal is completed, and the timing counter is triggered to work when the counter value is greater than or equal to 1. The working time of the timer is set to T seconds, after the timer ends, the digital baseband module starts data conversion again under the condition that the super capacitor has electricity, or waits for the super capacitor to be fully charged again before restarting. If the capacitor does not continuously supply energy, the digital baseband module is powered off, and the counter starts from 0, thereby avoiding continuous sending caused by continuous power supply.

2. Anti-collision tag chip for room division monitoring according to claim 1, characterized in that: The radio frequency front end includes an antenna and an impedance matching unit; the antenna is used for collecting external radio frequency signals and converting them into electric current, which is delivered to the controllable rectifier; and the impedance matching unit is used for converting the high impedance of the antenna into the low impedance required by the controllable rectifier.

3. The anti-collision tag chip for room division monitoring according to claim 1, characterized in that: The number of rectifiers in the multi-stage cascaded rectifier is 2-10.

4. The anti-collision tag chip for room division monitoring according to claim 1, characterized in that: The tag chip further includes an energy management circuit for judging and controlling the charging and discharging state of the super capacitor and controlling the working state of other modules.

5. A room division monitoring system characterized by The gateway and the anti-collision tag chip of any one of claims 1-4 are included. The gateway is used for emitting a carrier signal, receiving a modulation signal emitted by the tag chip, and interacting with an external network to transmit data to a target terminal.

6. The room division monitoring system of claim 5, wherein: The gateway reduces or increases the power of the carrier signal step by step, with the number of steps being set as n, and the power being reduced or increased step by step between the full power Y and the minimum threshold power X by (Y-X) / n steps, and one cycle is a process of reducing the power to the minimum threshold power X and then increasing the power to the full power.

7. The room division monitoring system of claim 5, wherein: The room antenna is also connected to the gateway trunk.

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