CN-122001458-A - Multi-node OOK back scattering system and implementation method

CN122001458ACN 122001458 ACN122001458 ACN 122001458ACN-122001458-A

Abstract

The invention discloses a multi-node OOK back scattering system and an implementation method, which relate to the technical field of wireless communication and comprise a plurality of sensor nodes and transceivers, and the data transmission is realized by adopting an OOK modulation mode, and the signal is reflected by the back scattering label to be communicated with the transceiver. The backscattering label of each node is differentiated in frequency spectrum by configuring different reflection frequency offset and subcarrier offset, so that interference among the nodes is restrained, and multi-node parallel communication is supported. By introducing a subcarrier polling receiving mechanism, software controls frequency switching, dynamic receiving of multiple subcarrier frequencies is realized, the data receiving time of each frequency point is strictly controlled, the system is ensured to capture signals from different subcarriers, and the reliability of parallel receiving is improved. The system power consumption is obviously reduced, and meanwhile, the communication stability and the frequency spectrum efficiency are improved. The method is suitable for deployment requirements of a large-scale wireless sensor network, and provides a low-power consumption and high-efficiency communication solution for the Internet of things equipment.

Inventors

FENG MAN
DANG JIACHENG
ZHANG LIFAN
LI JIANING
LU WEIBING

Assignees

东南大学

Dates

Publication Date: 20260508
Application Date: 20260126

Claims (7)

1. A multi-node OOK back scattering system is characterized by comprising a plurality of sensor nodes and at least one transceiver, wherein each sensor node is provided with at least one back scattering label, The back scattering label is used for transmitting data acquired from the sensor node to the transceiver through a reflection signal by adopting an on-off keying OOK modulation mode; A transceiver for receiving and demodulating the reflected signal from the backscatter tag; the backscattering label of each sensor node realizes the cooperative communication of a plurality of sensor nodes by configuring different subcarrier frequency offsets.
2. The multi-node OOK back-scattering system of claim 1, wherein the back-scattering tag is formed by a STM32L072 single chip microcomputer connected to a radio frequency switch, data sampling is performed through a preset time interval, collected data is transmitted to the transceiver through a switch reflection mode, the back-scattering tag adopts an OOK modulation mode, and modulation signal transmission after OOK modulation is achieved by adjusting a subcarrier reflection on-off state.
3. The multi-node OOK back-scattering system of claim 1, wherein the transceiver is implemented by a STM32F103 microcontroller connected to two SX1278 rf chips, wherein the two SX1278 rf chips are respectively responsible for transmitting continuous waves and receiving signals reflected from back-scattering tags of a plurality of sensor nodes, and recovering data through a demodulation algorithm, and the transceiver respectively allocates different subcarrier frequency offsets to each sensor node through modification of subcarrier frequency offsets.
4. The multi-node OOK back-scattering system of claim 1, further comprising a subcarrier polling receiving module, wherein, The system comprises a subcarrier polling receiving module, a control module and a data processing module, wherein the subcarrier polling receiving module is used for presetting a plurality of subcarrier frequency offsets in an initialization stage, each subcarrier frequency offset corresponds to the frequency of a reflected signal of a sensor node, switching the working frequency of a transceiver according to a set time interval or residence time sequence, enabling the transceiver to reside on each subcarrier frequency in sequence and detect and demodulate a tag reflected signal, the subcarrier polling receiving module generates a time reference through a system clock to realize dynamic switching of multiple subcarrier frequencies, the subcarrier polling receiving module records the current subcarrier index after receiving the reflected signal from a backscatter tag, and adds frequency identification in output demodulation data, so that modulation data of backscatter tags from different subcarrier frequencies are distinguished, after data receiving of the backscatter tag corresponding to the current subcarrier frequency is completed, the transceiver is controlled to switch to the next subcarrier frequency, and the switching time stamp is updated to ensure stable receiving residence time of each frequency point.
5. The method for implementing the multi-node OOK back-scattering system based on claim 1, comprising the following steps: step 1, node configuration and label initialization: In the system deployment stage, each sensor node is provided with a back-scattering tag which communicates with a transceiver in an OOK modulation mode, and the back-scattering tag transmits modulation data by controlling the state of reflection; step2, modulation and transmission of the reflected signals: The sensor node sends the collected signal to the back scattering label, the back scattering label reflects the external radio frequency signal through the received sensor collected signal, the radio frequency switch in the back scattering label is switched between an open circuit state and a short circuit state according to the control signal, and then the collected signal is modulated through the reflection state; Step 3, subcarrier frequency offset and spectrum resource management: According to a preset frequency spectrum resource allocation strategy, allocating unique subcarrier frequency offset parameters to the corresponding backscatter tags of each sensor node, and introducing allocated subcarrier frequency offset when each backscatter tag performs OOK modulation during reflection modulation so as to enable the frequency spectrum center of a reflected signal to generate corresponding frequency offset relative to an incident carrier; Step 4, after receiving the reflected signals from the plurality of backscatter tags, the transceiver demodulates the received signals: The transceiver detects the reflected signals on different sub-carrier frequency points according to the pre-configured sub-carrier frequency offset parameters, and carries out OOK demodulation on the detected signals, in the demodulation process, the transceiver judges the change condition of the amplitude of the reflected signals along with time and recovers the original binary data corresponding to the reflected signals, and after demodulation, the transceiver correlates the recovered data with the corresponding sub-carrier frequency information to distinguish the back scattering data from different sensor nodes, thereby realizing the identification and the reception of multi-node data.
6. The method of claim 5, wherein in step 3, the transceiver first marks the signal source according to the index corresponding to each subcarrier frequency, and each time the data packet of one subcarrier frequency is received, the receiver records the subcarrier frequency index to which the data packet belongs, and adds the index information to the data packet, so as to distinguish the signals from different backscatter tags in the subsequent data processing.
7. The method according to claim 5, wherein in step 4, the transceiver manages the receiving frequency by using a subcarrier polling receiving method, when the transceiver is initialized, an independent subcarrier frequency offset is allocated to each sensor node, each frequency offset corresponds to a reflected signal frequency of one sensor node, the transceiver is alternately switched to each subcarrier frequency according to a set time interval, after each switching to one subcarrier frequency, the transceiver performs data receiving on the frequency point, demodulates and marks a data packet, the transceiver demodulates according to the received reflected signal of each subcarrier frequency point, judges binary data corresponding to the reflected signal and recovers the original data, and an additional subcarrier frequency index is used in the demodulated signal to distinguish data sources of different subcarriers, before switching to the next subcarrier frequency point, the transceiver ensures that each subcarrier frequency point has a time residence, and the transceiver controls the frequency switching according to the time stamp and the polling time interval.

Description

Multi-node OOK back scattering system and implementation method Technical Field The invention relates to the technical field of wireless communication, in particular to a multi-node OOK back scattering system and an implementation method. Background With the development of internet of things (IoT) and wireless sensor networks, low power consumption and efficient wireless communication technologies have become key demands. The backscattering communication technology is one of indispensable communication modes in the Internet of things due to the characteristics of passive operation and low energy consumption. Particularly in a large-scale wireless sensor network, the back scattering communication technology can remarkably reduce energy consumption, reduce equipment maintenance cost and adapt to increasing connection requirements. Conventional backscatter systems typically use OOK modulation, which transmits data by adjusting the switching state of the reflected signal. Although OOK modulation techniques have low hardware complexity and power consumption, in multi-node communications, the spectral efficiency of signals is often low, and the performance of the system is significantly affected, especially in environments where multipath fading and spectral interference are present. In addition, the conventional method cannot effectively solve the problem of signal interference among multiple nodes, so that the spectrum utilization rate is low and the energy efficiency is wasted. Disclosure of Invention The invention aims to solve the technical problem of overcoming the defects of the prior art and providing a multi-node OOK back scattering system and an implementation method thereof, and aims to improve the energy efficiency and the communication range of the traditional OOK back scattering scheme, eliminate complex elements such as traditional inductance and capacitance by optimizing a load impedance module, and adopt a simplified open circuit/short circuit switch structure, thereby reducing the hardware complexity and improving the energy efficiency of the system. The invention adopts the following technical scheme for solving the technical problems: The multi-node OOK back scattering system provided by the invention comprises a plurality of sensor nodes and at least one transceiver, wherein each sensor node is provided with at least one back scattering label, The back scattering label is used for transmitting data acquired from the sensor node to the transceiver through a reflection signal by adopting an on-off keying OOK modulation mode; A transceiver for receiving and demodulating the reflected signal from the backscatter tag; the backscattering label of each sensor node realizes the cooperative communication of a plurality of sensor nodes by configuring different subcarrier frequency offsets. As a further optimization scheme of the multi-node OOK back scattering system, the back scattering label is formed by connecting an STM32L072 singlechip with a radio frequency switch, data sampling is carried out through a preset time interval, acquired data is transmitted to a transceiver in a switch reflection mode, the back scattering label adopts an OOK modulation mode, and modulation signal transmission after OOK modulation is realized by adjusting the on-off state of subcarrier reflection. As a further optimization scheme of the multi-node OOK back scattering system, the transceiver is realized by connecting an STM32F103 microcontroller with two SX1278 radio frequency chips, wherein the two SX1278 radio frequency chips are respectively responsible for transmitting continuous waves and receiving signals reflected by back scattering labels of a plurality of sensor nodes and recovering data through a demodulation algorithm, and the transceiver respectively distributes different subcarrier frequency offsets for each sensor node through modification of subcarrier frequency offset. As a further optimization scheme of the multi-node OOK back scattering system, the multi-node OOK back scattering system further comprises a subcarrier polling receiving module, wherein, The system comprises a subcarrier polling receiving module, a control module and a data processing module, wherein the subcarrier polling receiving module is used for presetting a plurality of subcarrier frequency offsets in an initialization stage, each subcarrier frequency offset corresponds to the frequency of a reflected signal of a sensor node, switching the working frequency of a transceiver according to a set time interval or residence time sequence, enabling the transceiver to reside on each subcarrier frequency in sequence and detect and demodulate a tag reflected signal, the subcarrier polling receiving module generates a time reference through a system clock to realize dynamic switching of multiple subcarrier frequencies, the subcarrier polling receiving module records the current subcarrier index after receiving the reflected signal from a back