Passive Bluetooth tag communication system based on trigger oscillator

Abstract

The invention discloses a passive Bluetooth tag communication system based on a triggered oscillator. The passive Bluetooth tag communication system comprises Bluetooth equipment, the triggered oscillator and a passive Bluetooth tag, the Bluetooth device is used for sending a Bluetooth data packet with a specified frequency, receiving a backscattering data packet carrying tag data sent by the passive Bluetooth tag and decoding the backscattering data packet to obtain the tag data; the trigger type oscillator is used for receiving a signal with a specific frequency sent by the Bluetooth equipment, amplifying the power of the signal with the specific frequency in a communication time period and then transmitting the signal with the specific frequency; and the passive Bluetooth tag is used for generating a Bluetooth format data packet, collecting radio frequency signal energy transmitted by the trigger oscillator, supplying energy to the passive Bluetooth tag by the collected and converted energy, and then sending the Bluetooth format data packet to the Bluetooth equipment in a backscattering manner based on a carrier signal of the frequency. The trigger oscillator is simple in structure and clear in working mechanism, and compared with a signal emission source in a traditional passive Bluetooth tag communication system, the trigger oscillator is simple in synchronization logic and relatively low in design and production cost.

Description

Technical Field

[0001] The invention belongs to the field of communication, and in particular relates to a passive Bluetooth tag communication system based on a triggered oscillator. Background Art

[0002] With the rapid development of mobile communication technology, a large number of Bluetooth and WiFi devices have appeared in our daily life, but the goal of "Internet of Everything" is still limited by the power consumption and energy supply of IoT nodes. Traditional Bluetooth devices need to generate a 2.4G carrier signal internally, making it difficult to reduce their power consumption and requiring regular battery replacement or charging.

[0003] Backscatter communication technology is a technology that achieves communication by reflecting electromagnetic signals in the environment. This technology uses a radio frequency switch to switch the antenna impedance to change the amplitude, frequency and phase of the reflected signal, so that the reflected signal meets a certain modulation method and data packet format, so that it can be received by the receiving device. Backscatter technology, with its excellent low power consumption characteristics, is expected to bring existing IoT devices such as Bluetooth and WiFi into the passive era, freeing them from the limitations of batteries or power cords.

[0004] Due to this vision, backscatter technology has been extensively studied in the field of low-power Bluetooth communications, but there are still many problems for large-scale commercial applications. For example, the patent with application number 202111155887.8 describes a method for Bluetooth backscattering, which allows Bluetooth tags to get rid of battery limitations. However, in addition to the passive Bluetooth tag and the signal Bluetooth device for receiving, this method also requires an additional signal transmitter to generate a single-tone carrier signal, which adds additional equipment and power consumption to the system, and the communication between the passive Bluetooth tag and the Bluetooth device lacks a synchronization mechanism. The patent with application number 202410025548.5, which is aimed at commercial Bluetooth devices, adds a two-way communication synchronization mechanism between the transmitter and the Bluetooth device, but this method essentially divides one of the Bluetooth devices in the communication between the two Bluetooth devices into two, which increases the complexity of the system and the additional device power consumption. The existing advanced Bluetooth backscatter communication system FreeRider technology replaces the transmitter in the above system or method with a Bluetooth device. Due to the problem of synchronization between the Bluetooth device and the passive tag, the data transmission bit error rate is high and stable communication cannot be achieved.

[0005] Disadvantages of existing technology: 1. An additional signal source needs to be added to the passive Bluetooth tag communication system to generate and transmit a single-tone carrier signal, which increases the system's additional power consumption.

[0006] 2. The synchronous communication mechanism in the passive Bluetooth tag communication system is either missing or too complicated, which increases the complexity and cost of the transmitter design. Summary of the invention

[0007] The object of the present invention is to provide a passive Bluetooth tag communication system based on a triggered oscillator in view of the defects of the prior art.

[0008] In order to achieve the above object, the present invention adopts the following technical scheme: a passive Bluetooth tag communication system based on a triggered oscillator, comprising: a Bluetooth device, a triggered oscillator and a passive Bluetooth tag; The Bluetooth device is used to send Bluetooth data packets of a specified frequency, and simultaneously receive backscattered data packets carrying tag data sent by a passive Bluetooth tag, and decode them to obtain the tag data; The triggered oscillator is used to receive a signal of a specific frequency sent by a Bluetooth device, amplify the signal power of the specific frequency and transmit it within a communication time period; The passive Bluetooth tag is used to generate a Bluetooth format data packet and to collect the radio frequency signal energy emitted by the triggered oscillator, and to power the passive Bluetooth tag with the collected converted energy, and then to send the Bluetooth format data packet to the Bluetooth device in a backscattering manner based on the carrier signal of this frequency.

[0009] Further, the triggered oscillator includes an antenna, an active resonant network, a timer, and a reset switch; The active resonant network is used to be in a critical state of oscillation under active bias, and the specific frequency sent by the Bluetooth device f After 0 is captured by the antenna, the active resonant network is triggered to enter an oscillation state, generating a frequency of f An oscillating signal of 0 is transmitted outward via the antenna during the communication time period; The timer is used to start timing a communication time period after the active resonant network is triggered, and to control the reset switch to reset the bias voltage of the active resonant network and stop transmitting the oscillation signal after the time period is reached.

[0010] Further, the passive Bluetooth tag includes an energy harvesting conversion module, a digital baseband module, and a backscatter modulation module; The energy collection and conversion module is used to rectify, store and boost the radio frequency signal energy received from the triggered oscillator to provide energy for the digital baseband and backscatter modulation modules; The digital baseband module is used to encapsulate the electronic product code of the passive Bluetooth tag or the data collected by the sensor into a Bluetooth data frame format; The backscatter modulation module is used to send the encapsulated Bluetooth data packet to the Bluetooth device in a backscattering manner.

[0011] Furthermore, the Bluetooth data frame format adopts Miller or Manchester encoding.

[0012] Furthermore, the modulation method adopted by the backscatter modulation module is a frequency-based modulation method. When transmitting data 0, a specific frequency f When transmitting data 1, a frequency shift of 2.5 MHz is added.

[0013] Furthermore, the modulation mode adopted by the backscatter modulation module is a phase-based modulation mode. When transmitting data 0, a single-tone carrier is given f 0 adds a 2MHz frequency shift; when transmitting data 1, a single tone carrier is given f 0 adds an additional 180 degrees of phase shift.

[0014] The present invention adopts a trigger oscillator to replace the transmitting source in the passive Bluetooth tag communication system, which has the following beneficial effects: 1. The trigger oscillator used in the present invention has a simple structure and a clear working mechanism. Compared with the signal transmission source in the traditional passive Bluetooth tag communication system, the design and production cost of the trigger oscillator is low.

[0015] 2. The present invention adds a synchronization mechanism to passive Bluetooth tag communication with lower design and hardware costs 3. The trigger oscillator used in the present invention has low power consumption. The power of the signal transmission source in the traditional passive Bluetooth tag communication system is at the milliwatt level or even higher, while the power consumption of the trigger oscillator is about 500uW. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is an overall system block diagram of a passive Bluetooth tag communication system based on a triggered oscillator according to an embodiment.

[0017] Figure 2 is a structural block diagram of a triggered oscillator according to an embodiment.

[0018] Figure 3 is a functional block diagram of a passive Bluetooth tag according to an embodiment. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0020] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0021] A passive Bluetooth tag communication system based on a triggered oscillator. The overall system block diagram is as follows: Figure 1 As shown, it includes: a Bluetooth device, a triggered oscillator, and a passive Bluetooth tag.

[0022] Among them: Bluetooth devices, used to transmit specific frequencies f 0 Bluetooth data packet as the excitation signal to activate the triggered oscillator to generate a single-tone carrier f 0; at a specific frequency f After the Bluetooth data packet of 0 is transmitted, the Bluetooth device enters the receiving mode, waiting to receive the backscattered data packet carrying the tag data sent by the passive Bluetooth tag, and decodes it to obtain the tag data.

[0023] Trigger oscillator, the block diagram is as follows Figure 2 As shown, the composition includes an antenna, an active resonant network, a timer and a reset switch; the resonant network is in a critical state of oscillation under active bias, and a specific frequency f After the Bluetooth excitation signal of 0 is captured by the triggered oscillator antenna, the active resonant network is triggered to enter the oscillation state, generating a frequency of f The oscillation signal of 0 is transmitted outward through the antenna; the timer counts a communication time cycle, and when the time cycle is reached, the reset switch is controlled to reset the bias voltage of the active resonant network, and the transmission frequency is stopped. f 0 single tone carrier signal.

[0024] Passive Bluetooth tag, functional block diagram as follows Figure 3As shown, the functional modules include a backscatter modulation module, an energy collection and conversion module, and a digital baseband part. After the single-tone carrier signal emitted by the triggered oscillator is received by the passive Bluetooth tag antenna, it enters the energy collection and conversion module. After rectification, storage, and boost conversion, the electrical signal supplies energy to the digital baseband and backscatter modulation modules. The digital baseband module encapsulates the electronic product code of the passive Bluetooth tag or the data collected by the sensor into a Bluetooth data frame format. In order to improve the sensitivity and anti-interference ability of the communication system, the passive Bluetooth tag data frame can adopt Miller or Manchester encoding methods, and then control the backscatter modulation module for modulation in a binary keying mode. There are two modulation methods for the backscatter modulation module, frequency-based modulation and phase-based modulation. When modulating in a frequency manner, when transmitting data 0, the reverse modulation module gives a specific frequency. f When transmitting data 0, the reverse modulation module adds a 2MHz frequency shift to the single-tone carrier; when transmitting data 1, the reverse modulation module adds a 2.5MHz frequency shift. For Bluetooth backscatter communication, the bit error rate of phase modulation is lower than that of frequency modulation. When using phase modulation, when transmitting data 0, the reverse modulation module only adds a 2MHz frequency shift to the single-tone carrier. f 0 adds 2MHz frequency shift; when transmitting data 1, the reverse modulation module gives a single tone carrier f 0 additional 180 degree phase shift. The modulated signal of the passive Bluetooth tag is transmitted to the Bluetooth device through the antenna.

[0025] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A passive Bluetooth tag communication system based on a triggered oscillator, characterized in that include: Bluetooth devices, triggered oscillators, and passive Bluetooth tags; The Bluetooth device is used to send Bluetooth data packets of a specified frequency, and simultaneously receive backscattered data packets carrying tag data sent by a passive Bluetooth tag, and decode them to obtain the tag data; The triggered oscillator is used to receive a signal of a specific frequency sent by a Bluetooth device, amplify the signal power of the specific frequency and transmit it within a communication time period; The passive Bluetooth tag is used to generate a Bluetooth format data packet and to collect the radio frequency signal energy emitted by the triggered oscillator, and to power the passive Bluetooth tag with the collected converted energy, and then to send the Bluetooth format data packet to the Bluetooth device in a backscattering manner based on the carrier signal of this frequency.

2. The passive Bluetooth tag communication system based on a triggered oscillator according to claim 1, characterized in that: The triggered oscillator includes an antenna, an active resonant network, a timer and a reset switch; The active resonant network is used to be in a critical state of oscillation under active bias, and the specific frequency sent by the Bluetooth device f After 0 is captured by the antenna, the active resonant network is triggered to enter an oscillation state, generating a frequency of f An oscillating signal of 0 is transmitted outward via the antenna during the communication time period; The timer is used to start timing a communication time period after the active resonant network is triggered, and to control the reset switch to reset the bias voltage of the active resonant network and stop transmitting the oscillation signal after the time period is reached.

3. The passive Bluetooth tag communication system based on a triggered oscillator according to claim 1, characterized in that: The passive Bluetooth tag includes an energy collection conversion module, a digital baseband module and a backscatter modulation module; The energy collection and conversion module is used to rectify, store and boost the radio frequency signal energy received from the triggered oscillator to provide energy for the digital baseband and backscatter modulation modules; The digital baseband module is used to encapsulate the electronic product code of the passive Bluetooth tag or the data collected by the sensor into a Bluetooth data frame format; The backscatter modulation module is used to send the encapsulated Bluetooth data packet to the Bluetooth device in a backscattering manner.

4. The passive Bluetooth tag communication system based on a triggered oscillator according to claim 3, characterized in that: The Bluetooth data frame format adopts Miller or Manchester encoding.

5. The passive Bluetooth tag communication system based on a triggered oscillator according to claim 3, characterized in that: The modulation mode adopted by the backscatter modulation module is a frequency-based modulation mode. When transmitting data 0, a specific frequency f When transmitting data 1, a frequency shift of 2.5 MHz is added.

6. The passive Bluetooth tag communication system based on a triggered oscillator according to claim 3, characterized in that: The modulation mode adopted by the backscatter modulation module is a phase-based modulation mode. When transmitting data 0, a single-tone carrier is given f 0 adds a 2MHz frequency shift; when transmitting data 1, a single tone carrier is given f 0 adds an additional 180 degrees of phase shift.

Images