CN105303207B - A kind of tag communication system based on analog-to-digital conversion backscattering - Google Patents

Abstract

The present invention relates to a tag communication system, specifically a tag communication system based on analog-to-digital conversion backscattering, including a hybrid tag and a hybrid reader tag, both of which are integrated with a WISP sensing platform; hybrid reading The reader tag also includes a reader circuit, and the reader circuit includes a microprocessor of the model MSP430, a battery, a first switch S1, a radio frequency switch, and an antenna; both the hybrid tag and the hybrid reader tag are also integrated with an analog-to-digital conversion reverse The scattering circuit, the analog-to-digital conversion backscattering circuit includes a digital radio frequency field effect transistor Q1, an antenna, a radio frequency switch So and a temperature sensor. Through the WISP sensing platform, combined with analog-to-digital conversion backscattering and reader functions, the present invention well solves the problems of unsmooth information between tags, low tag communication efficiency, and high power consumption of tag communication. The development of the system has played a very good role in promoting.

Description

A Tag Communication System Based on Analog-to-Digital Conversion Backscatter

technical field

The invention relates to a tag communication system, in particular to a tag communication system based on analog-to-digital conversion backscattering.

Background technique

In recent years, with the rapid development of radio frequency identification technology, tag identification technology has gradually occupied an important position in national life from politics and economy to society and life. Although the development of radio frequency identification technology in my country has matured, the existence of readers not only increases energy consumption, but also forms a barrier to communication between tags. According to the survey, the energy consumption of the passive tag system is mainly generated by the reader; in addition, due to the existence of the reader, the information between the tags is not smooth, resulting in a decrease in tag communication efficiency. Therefore, it is urgent to realize the communication between tags, improve the reliability of tag communication, and reduce the power consumption of tag communication.

Contents of the invention

The present invention provides a tag communication system based on analog-to-digital conversion backscattering in order to solve the problems of high energy consumption of readers, unsmooth communication between tags and low communication efficiency between tags in the existing passive tag system.

The present invention is realized by adopting the following technical scheme: a tag communication system based on analog-to-digital conversion backscattering, including a hybrid tag and a hybrid reader tag, both of which are integrated with a WISP sensing platform;

The mixed reader tag also includes a reader circuit, the reader circuit includes a microprocessor of the model MSP430, the ground terminal of the microprocessor is grounded, the power supply terminal is connected to the battery through the first switch S1, and the output terminal of the microprocessor is connected to the inverter. The input terminal of the phaser U0 is grounded, the output terminal of the inverter U0 is connected to the control terminal of the radio frequency switch, the output terminal of the microprocessor is also connected to the control terminal of the radio frequency switch, the power supply terminal of the radio frequency switch is connected to the power supply terminal of the microprocessor Connection, the output terminal of the RF switch is connected to the antenna in the WISP sensing platform, and the ground terminal of the RF switch is grounded;

Both the hybrid tag and the hybrid reader tag are also integrated with an analog-to-digital conversion backscatter circuit. The analog-to-digital conversion backscatter circuit includes a digital radio frequency field effect transistor Q1, the drain of the digital radio frequency field effect transistor Q1 and the WISP sensing platform. The digital end of the antenna is connected, the source is grounded, the analog end of the antenna is connected to one end of the temperature sensor through a radio frequency switch So, and the other end of the temperature sensor is grounded.

Both the hybrid tag and the hybrid reader tag can work in digital backscatter mode and analog backscatter mode. The digital backscatter mode is the default mode and complies with the EPC Gen 2 RFID protocol. The RF switch So is in the off state and disconnected Connection of the temperature sensor to the antenna; in the simulated backscatter mode, the RF switch So is turned on and the temperature sensor is connected to the antenna. The WISP sensing platform in the tag is a flexible RF power supply platform. The platform integrates microcontrollers, sensor arrays and antennas. The microcontroller in the platform controls the RF switch So and digital RF field effect transistor Q1. WISP sensing The platform can sense the environment to control the RF switch So, and the backscatter mode can be selected by adjusting the external RF field. The analog-to-digital conversion backscattering circuit selects the data transmission mode according to the suitability of the environment, analog or digital mode, which greatly improves the transmission efficiency and thus the transmission quality, which is several times higher than the previous single mode transmission data efficiency.

The function of the reader is integrated in the hybrid reader tag, so that there is no need for a separate reader in the tag communication system, which reduces the energy consumption in the tag communication system; in addition, the tag communication system used to be transmitted through the reader, which may be transmitted during the transmission process. Phenomena such as packet loss will occur, but now direct tag communication can improve communication quality and efficiency.

A tag communication system based on analog-to-digital conversion backscattering, through the WISP sensing platform, combined with the analog-to-digital conversion backscattering function, absorbs energy through the environment, and adjusts and converts analog and digital communications according to the environment, which is a good solution It solves the problems of poor information flow between tags, low tag communication efficiency, and high power consumption of tag communication, and plays a very good role in promoting the development of passive tag communication systems.

Description of drawings

Figure 1 is a schematic diagram of the WISP sensing platform.

Figure 2 is a schematic diagram of the reader circuit.

Figure 3 is a schematic diagram of the temperature difference detection circuit.

Figure 4 is a schematic diagram of the analog-to-digital conversion backscattering circuit.

Detailed ways

A tag communication system based on analog-to-digital conversion backscatter, including a hybrid tag and a hybrid reader tag, both of which are integrated with a WISP sensing platform;

The mixed reader tag also includes a reader circuit, the reader circuit includes a microprocessor of the model MSP430, the ground terminal of the microprocessor is grounded, the power supply terminal is connected to the battery through the first switch S1, and the output terminal of the microprocessor is connected to the inverter. The input terminal of the phaser U0 is grounded, the output terminal of the inverter U0 is connected to the control terminal of the radio frequency switch, the output terminal of the microprocessor is also connected to the control terminal of the radio frequency switch, the power supply terminal of the radio frequency switch is connected to the power supply terminal of the microprocessor Connection, the output terminal of the RF switch is connected to the antenna in the WISP sensing platform, and the ground terminal of the RF switch is grounded;

Both the hybrid tag and the hybrid reader tag are also integrated with an analog-to-digital conversion backscatter circuit. The analog-to-digital conversion backscatter circuit includes a digital radio frequency field effect transistor Q1, the drain of the digital radio frequency field effect transistor Q1 and the WISP sensing platform. The digital end of the antenna is connected, the source is grounded, the analog end of the antenna is connected to one end of the temperature sensor through a radio frequency switch So, and the other end of the temperature sensor is grounded.

Both the hybrid tag and the hybrid reader tag include a temperature difference detection circuit, and the temperature difference detection circuit includes a sensor, a first operational amplifier U1, a second operational amplifier U2, a third operational amplifier U3 and a fourth operational amplifier U4, The antenna in the WISP sensing platform is connected to the anode of the first crystal diode D1, the cathode of the first crystal diode D1 is grounded through the first capacitor C1, and the cathode of the first crystal diode D1 is connected to the first resistor R1 and the first operational amplifier U1. The inverting terminal is connected, the non-inverting terminal of the first operational amplifier U1 is grounded, the inverting terminal is also connected to the anode of the third crystal diode D3, the cathode of the third crystal diode D3 is connected to the output terminal of the first operational amplifier U1, and the first operation The output terminal of the amplifier U1 is also connected to the inverting terminal of the third operational amplifier U3 through the third resistor R3, the output terminal of the sensor is connected to the anode of the second crystal diode D2, and the cathode of the second crystal diode D2 is grounded through the second capacitor C2 , the cathode of the second crystal diode D2 is also connected to the inverting terminal of the second operational amplifier U2 through the second resistor R2, the non-inverting terminal of the second operational amplifier U2 is grounded, the inverting terminal of the second operational amplifier U2 and the fourth crystal diode The anode of D4 is connected, the cathode of the fourth crystal diode D4 is connected to the output terminal of the second operational amplifier U2, the output terminal of the second operational amplifier U2 is connected to the non-inverting terminal of the third operational amplifier U3 through the fourth resistor R4, and the third operational amplifier The inverting terminal of the amplifier U3 is connected to the output terminal through the fifth resistor R5, the non-inverting terminal is grounded through the sixth resistor R6, the output terminal of the third operational amplifier U3 is connected to the non-inverting terminal of the fourth operational amplifier U4, and the output terminal of the fourth operational amplifier U4 The inverting terminal is grounded through the seventh resistor R7 and the third capacitor C3.

The temperature difference detection circuit is composed of an envelope detection circuit, a subtraction circuit and a threshold circuit. The envelope detection circuit includes antennas, sensors, diodes, resistors and capacitors. The function of the envelope detection circuit is to track the envelope of the received signal and eliminate Beyond the carrier frequency, the circuit uses passive components and is therefore ultra-low power in nature. Diodes in the circuit act as switches, allowing current to flow forward instead of reverse; capacitor elements store charge; resistors regulate current flow, and by setting appropriate values for these analog elements, the carrier frequency can be removed; the subtraction circuit consists of the first operation The single release device U1, the second operational single release device U2, the third operational single release device U3, the subtraction circuit is to divide the amplitude received on the antenna and the value measured by the local sensor; the threshold value circuit includes the fourth operational amplifier U4, The purpose of the threshold circuit is to compare the threshold to the ratio of the sensor. It measures the difference in temperature between two locations by comparing to a threshold. At a higher level, the threshold circuit calculates the average of the two voltage levels. When the input is greater than the threshold, a 1 bit is output; otherwise, a 0 bit is output. To calculate this average, before using an envelope detector, we use specific values of resistors and capacitors to calculate the average value of the signal envelope. Through the design of the logarithmic conversion circuit, the temperature difference detection circuit converts the huge energy-consuming subtraction calculation circuit into a low-power logarithmic temperature difference detection circuit, which greatly saves energy consumption.

Claims (1)

1. A tag communication system based on analog-to-digital conversion backscattering, characterized in that it includes a hybrid tag and a hybrid reader tag, and a WISP sensing platform is integrated in the hybrid tag and the hybrid reader tag; The mixed reader tag also includes a reader circuit, the reader circuit includes a microprocessor of the model MSP430, the ground terminal of the microprocessor is grounded, the power supply terminal is connected to the battery through the first switch S1, and the output terminal of the microprocessor is connected to the inverter. The input terminal of the phaser U0 is grounded, the output terminal of the inverter U0 is connected to the control terminal of the radio frequency switch, the output terminal of the microprocessor is also connected to the control terminal of the radio frequency switch, the power supply terminal of the radio frequency switch is connected to the power supply terminal of the microprocessor Connection, the output terminal of the RF switch is connected to the antenna in the WISP sensing platform, and the ground terminal of the RF switch is grounded; Both the hybrid tag and the hybrid reader tag are also integrated with an analog-to-digital conversion backscatter circuit. The analog-to-digital conversion backscatter circuit includes a digital radio frequency field effect transistor Q1, the drain of the digital radio frequency field effect transistor Q1 and the WISP sensing platform. The digital end of the antenna is connected, the source is grounded, the analog end of the antenna is connected to one end of the temperature sensor through a radio frequency switch So, and the other end of the temperature sensor is grounded.