A Low-Power Short-Range Communication System and Method for Sensors Based on GMSK

Abstract

This application provides a low-power, short-range sensor communication system and method based on GMSK, belonging to the field of wireless communication technology. The system includes a coordinator node, a host computer, and at least one sensor node. The sensor node collects monitoring data, performs simplified binary encoding, executes GMSK modulation, and transmits the data. The coordinator node and the sensor node are wirelessly connected to form a star-shaped wireless communication network, used to receive and demodulate GMSK signals, and perform verification, decoding, and aggregation processing on the demodulated data. The host computer is connected to the coordinator node via a wired interface, used to receive and display data and issue control commands. The coordinator node modulates the control commands and forwards them to the corresponding sensor nodes. This invention, by combining GMSK modulation with a star network topology, achieves low-power, anti-interference, and high-capacity short-range sensor communication, suitable for industrial scenarios such as power distribution rooms, buildings, and distributed photovoltaic systems.

Description

Technical Field

[0001] This application belongs to the field of wireless communication technology, specifically relating to a sensor low-power short-range communication system and method based on GMSK. Background Technology

[0002] With the rapid development of industrial automation and the energy internet, a large number of distributed sensors are needed in enclosed or semi-enclosed scenarios such as power distribution rooms, industrial buildings, and distributed photovoltaic power stations for smoke detection, temperature and humidity monitoring, and equipment status monitoring. These applications have high requirements for wireless communication, with communication distances typically within 100 meters, low data transmission rates but high reliability requirements. Sensor nodes are mostly battery-powered and therefore extremely sensitive to power consumption, and also need to have certain wall penetration capabilities and resistance to industrial electromagnetic interference.

[0003] Currently, wireless communication solutions for the aforementioned short-range, low-power sensing scenarios mainly include LoRa-based and BLE-based solutions. LoRa-based solutions utilize spread spectrum modulation technology, offering advantages such as long transmission distance and controllable low-data-rate power consumption. However, LoRa's physical layer protocol is a closed-source scheme, with underlying modulation and demodulation parameters fixed by the chip manufacturer. Developers cannot optimize for short-range scenarios within 100 meters and must accept the complex protocol stack overhead designed for long-range wide-area networks, resulting in unnecessary resource consumption. Furthermore, LoRa is designed for long-range transmission, exhibiting significant power redundancy in short-range scenarios within 100 meters, and dedicated chips are expensive. BLE-based solutions, on the other hand, offer advantages such as small module size and extremely low standby power consumption, but still suffer from the following drawbacks: communication distance is typically less than 10 meters, signal attenuation is severe after penetrating walls, making it unsuitable for industrial environments with wall obstructions; single-gateway network capacity is limited, making it difficult to support multi-node distributed deployment; and resistance to industrial electromagnetic interference is weak, easily leading to data packet loss and connection instability in environments with strong interference sources such as frequency converters and contactors.

[0004] Therefore, there is an urgent need for a short-range sensor communication method and system that is low-power, anti-interference, has a large-capacity networking capability, and features open protocols and flexible customization. Summary of the Invention

[0005] In a first aspect, embodiments of this application provide a GMSK-based low-power short-range sensor communication system, including a coordinator node, a host computer, and at least one sensor node; The coordinator node is wirelessly connected to each sensor node to form a star-shaped wireless communication network, and the coordinator node is connected to the host computer via a communication cable. Sensor nodes are used to collect monitoring data, perform GMSK modulation on the monitoring data after simplified binary encoding to obtain GMSK signals, and send them to the coordinator nodes. The coordinator node is used to receive and demodulate the GMSK signals sent by the sensor nodes, and to perform verification, decoding and summarization processing on the demodulated data. The host computer is used to receive and display the data uploaded by the coordinator node, and to send control commands to the coordinator node; The coordinator node modulates the control command and forwards it to the corresponding sensor node, which then performs the corresponding operation based on the control command.

[0006] Furthermore, the sensor node includes a sensing element, a first communication component, a power management unit, and a controller; Sensing elements are used to collect monitoring data in real time and output analog or digital signals. The first communication component includes a baseband GMSK modem, an analog front-end, and an antenna. The baseband GMSK modem is used to perform GMSK modulation on the data to be transmitted and GMSK demodulation on the received signal. The analog front-end is used to filter, amplify, and up-convert the modulated analog signal, and to down-convert, filter, and amplify the received radio frequency signal. The antenna is used to convert the radio frequency signal processed by the analog front-end into electromagnetic waves for transmission, and to receive electromagnetic waves in space and convert them into radio frequency signals. The controller includes a low-power microprocessor, a sleep timer driven by an RC oscillator, and a wake-up interrupt circuit; the low-power processor is used to control data acquisition, simplified binary encoding, and instruction parsing and execution; the sleep timer is used for sleep-wake scheduling of communication components; the power management unit is used to provide power to sensor nodes and upload alarm signals when the battery is low; the power management unit includes a lithium battery and a voltage monitoring circuit.

[0007] Furthermore, the coordinator node includes a second communication component, a data processor, a memory, an interface, and a low-power clock monitoring circuit. The second communication component matches the parameters of the first communication component of the sensor node. The second communication component is used to receive and demodulate the GMSK signal of the sensor node, as well as to send modulation control commands to the sensor node. The data processor uses a microprocessor to perform CRC verification, decoding, and data aggregation on the demodulated data, process retransmission requests, allocate communication addresses for sensor nodes, and realize network management. The memory is used to temporarily store real-time monitoring data; The interface uses an Ethernet interface or an RS485 interface for wired connection to the host computer; A low-power clock monitoring circuit is used to remain operational while the coordinator node enters a deep sleep state to monitor for wake-up signals or emergency data in the channel, and to wake up the second communication component and data processor when a valid signal is detected.

[0008] Furthermore, it also includes at least one relay node; Relay nodes are deployed in areas where wireless signals are obstructed to forward GMSK signals between sensor nodes and coordinator nodes.

[0009] Secondly, embodiments of this application also provide a low-power, short-range sensor communication method based on GMSK, applied to the system described in the first aspect, comprising the following steps: S1. The sensor node awakens from deep hibernation, scans the channel and receives beacon frames periodically broadcast by the coordinator node, and establishes synchronization and network connection with the coordinator node. S2. When the preset acquisition cycle is reached, the sensor node wakes up its sensing element to acquire raw monitoring data, and its controller performs simplified binary encoding on the raw monitoring data to generate the encoded data payload. S3. The first communication component of the sensor node performs GMSK modulation on the encoded data payload, generates a GMSK modulated signal, and sends it to the coordinator node through the antenna; S4. The coordinator node listens to the channel and receives the GMSK modulated signal, performs GMSK demodulation to obtain the demodulated data, and verifies the correctness of the demodulated data. S5. The coordinator node decodes and summarizes the verified demodulated data, uploads it to the host computer via communication cable, and receives control commands from the host computer. It then modulates the control commands and forwards them to the corresponding sensor nodes. S6. After completing a single data transmission or command interaction, both the sensor node and the coordinator node enter a deep sleep state, maintaining only low-power clock monitoring, and are woken up in the next preset acquisition cycle or when a wake-up command is received, returning to step S2.

[0010] Furthermore, the specific steps of step S1 are as follows: S11. The sensor node automatically wakes up when the built-in sleep timer reaches the preset sleep period, or wakes up after receiving an external wake-up signal. After waking up, the sensor node scans the channel. S12. The coordinator node periodically broadcasts beacon frames, the beacon frames containing the network reference clock (NTB) timestamp of the coordinator node's local clock; S13. The sensor node calculates an estimate of the network reference clock by parsing the timestamp in the received beacon frame and combining it with its local clock. :

[0011] in, This is the local clock value when the sensor node finishes receiving the beacon frame. Send timestamps for the coordinator nodes carried in the beacon frames. The arrival time of the beacon frame is recorded locally by the sensor node; S14. Sensor node estimation based on network reference clock Establish time synchronization with the coordinator node and use an estimate of the network reference clock. Compensation calibration is performed on the sleep timer driven by the RC oscillator.

[0012] Furthermore, the specific steps of step S2 are as follows: S21. When the preset acquisition period is reached, the controller of the sensor node wakes up the sensing element to acquire raw monitoring data in real time. ; S22. The controller processes the raw monitoring data. The analog sensor data is quantized according to a preset precision P and converted into an N-bit binary number, where:

[0013] The controller will process the raw monitoring data. The data from the switching sensor is encoded as a 1-bit binary status flag. S23. All encoded data are concatenated in binary format according to a preset compact frame format, and redundant information is removed to generate encoded data payload.

[0014] Furthermore, the specific steps of step S3 are as follows: S31. The first communication component of the sensor node performs GMSK modulation on the encoded data payload. The modulation parameters include the operating frequency band, preset Gaussian filter parameters, modulation index, channel bandwidth, and modulation rate corresponding to the signal bandwidth. S32. The modulated GMSK signal is framed according to the physical layer radio frame format, wherein the physical layer radio frame includes a preamble, a start-of-frame symbol, a physical frame header (PHR), and a physical layer service data unit (PSDU) in sequence; the start-of-frame symbol is used to indicate whether forward error correction is performed on the physical frame header (PHR) and the physical layer service data unit (PSDU). S33. Identify the start-of-frame character and, when forward error correction is required, add forward error correction coding to the Physical Frame Header (PHR) and Physical Layer Service Data Unit (PSDU) before modulation. The forward error correction coding includes binary convolutional coding and interleaving coding. S34. After being modulated and framed, the GMSK signal is processed by the analog front-end and then transmitted to the coordinator node through the antenna.

[0015] Furthermore, the specific steps of step S4 are as follows: S41. The coordinator node continuously monitors the channel. When it receives a GMSK modulated signal, it filters the GMSK modulated signal to remove interference signals, then amplifies it, and finally performs GMSK demodulation to obtain demodulated data. S42. The coordinator node performs a 12-bit CRC check and a 5-bit BCH(31,26) check on the physical frame header (PHR) in the demodulated data. If the verification fails, discard the current frame and record the error; If the verification passes, proceed to step S43; S43. Extract the Physical Layer Service Data Unit (PSDU) from the FLEN field in the Physical Frame Header (PHR) and perform a 24-bit CRC24 check on the PSDU. If the verification is successful, the coordinator node will pass the demodulated data to the data processor as the verified data. If the verification fails, the coordinator node constructs and sends a retransmission instruction frame to the corresponding sensor node. The specific steps of step S6 are as follows: S61. After completing a single data transmission or command interaction, the sensor node enters a deep sleep state, the sensing element and the first communication component are powered off, the high-speed clock in the controller is powered off, and only the sleep timer and wake-up interrupt circuit driven by the RC oscillator continue to work. S62. The coordinator node simultaneously enters a deep sleep state, the second communication component is powered off, and only the low-power clock listening circuit is retained. S63. When the sleep timer count of the sensor node reaches the preset sleep cycle threshold. When this occurs, a wake-up interrupt is generated, power is restored, and the process returns to step S2; Alternatively, when the coordinator node hears a wake-up command from the host computer or emergency data from the sensor node, it wakes up the coordinator node and forwards the wake-up command to the corresponding sensor node. S64. After the sensor node wakes up, it uses an estimated value from the network reference clock. Synchronize the local clock in terms of frequency and phase, and compensate for the frequency drift of the RC oscillator caused by temperature or voltage changes during sleep, then return to step S2.

[0016] Furthermore, it also includes the step of time-slot scheduling of multiple sensor nodes by the coordinator node: S7. The coordinator node maintains a dynamic time slot allocation table and allocates uplink communication time slots to each sensor node that successfully joins the network. The coordinator node embeds time slot allocation information into periodically broadcast beacon frames; Each sensor node only sends the collected data within its allocated uplink communication time slot, and remains in deep sleep or only listens for broadcast messages during the remaining uplink communication time slots.

[0017] As can be seen from the above technical solutions, this application has the following advantages: The GMSK-based low-power short-range sensor communication system and method provided in this application employs GMSK modulation technology, which allows for free optimization of physical layer parameters, enabling developers to customize it for short-range industrial scenarios within 100 meters. By simplifying binary encoding to reduce data transmission volume, combined with deep sleep wake-up and NTB clock compensation technology, the system improves lithium battery power supply life and reduces maintenance costs. Through GMSK modulation, coupled with multi-level verification and optional forward error correction coding, the system enhances data transmission success rate in industrial environments with strong interference. Unified management by the coordinator node in a star topology enables dynamic time slot allocation; a single coordinator node can connect dozens of sensor nodes, adapting to multi-node distributed deployment scenarios such as power distribution rooms, buildings, and distributed photovoltaic systems. Furthermore, the GMSK hardware circuit is simple, uses universal components, and has low overall deployment costs. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the GMSK-based sensor low-power short-range communication system of the present invention.

[0020] Figure 2 This is a flowchart illustrating the GMSK-based low-power short-range sensor communication method of the present invention. Detailed Implementation

[0021] Various embodiments of this disclosure will be described more fully in the GMSK-based sensor low-power short-range communication system described in detail below. This disclosure may have various embodiments, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of this disclosure to the specific embodiments disclosed herein, but rather this disclosure should be understood to cover all adjustments, equivalents, and / or alternatives falling within the spirit and scope of the various embodiments of this disclosure.

[0022] This embodiment provides a GMSK-based low-power short-range sensor communication system, which achieves autonomous control and ultra-low power consumption in industrial sensor communication based on GMSK modulation and sleep mechanisms.

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1 The diagram shown is a schematic of a GMSK-based low-power short-range sensor communication system in a specific embodiment. The system includes a coordinator node, a host computer, and at least one sensor node. The coordinator node is wirelessly connected to each sensor node to form a star-shaped wireless communication network, and the coordinator node is connected to the host computer via a communication cable. It should be noted that the coordinator node is wirelessly connected to each sensor node, eliminating the need for wiring and adapting to complex industrial site layouts. It also uses GMSK modulation, which has strong anti-interference capabilities and a stable transmission distance of 100 meters. The communication cable connecting the coordinator node to the host computer ensures the reliability and real-time performance of data uploads, unaffected by wireless interference, while also providing continuous power to the coordinator node. Sensor nodes are used to collect monitoring data, perform GMSK modulation on the monitoring data after simplified binary encoding to obtain GMSK signals, and send them to the coordinator nodes. It should be noted that the sensor node performs data acquisition, simplified encoding, GMSK modulation and transmission, and can go into sleep mode with low power consumption, enabling flexible deployment and long-term operation without an external power supply. The coordinator node is used to receive and demodulate the GMSK signals sent by the sensor nodes, and to perform verification, decoding and summarization processing on the demodulated data. It should be noted that the coordinator node can receive data from multiple sensor nodes, verify and decode it, and aggregate and store it. It can also upload the data to the host computer via a wired connection and issue control commands to achieve unified management of the star network. The host computer is used to receive and display the data uploaded by the coordinator node, and to send control commands to the coordinator node; It should be noted that the host computer provides a human-machine interface, which displays monitoring data in real time and can issue commands, facilitating monitoring and maintenance; The coordinator node modulates the control command and forwards it to the corresponding sensor node, which then performs the corresponding operation based on the control command.

[0025] This embodiment achieves ultra-low power operation of sensor nodes and strong anti-interference communication in industrial environments by using GMSK modulation and demodulation and star networking, and employing a sleep timer and simplified binary encoding, thus meeting the requirements of independent controllability.

[0026] Furthermore, as a refinement and extension of the specific implementation of the above embodiments, in order to fully illustrate the specific implementation process in this embodiment, another GMSK-based low-power short-range sensor communication system is provided, which includes a coordinator node, a host computer, and at least one sensor node. The coordinator node is wirelessly connected to each sensor node to form a star-shaped wireless communication network, and the coordinator node is connected to the host computer via a communication cable. Sensor nodes are used to collect monitoring data, perform GMSK modulation on the monitoring data after simplified binary encoding to obtain GMSK signals, and send them to the coordinator nodes. The coordinator node is used to receive and demodulate the GMSK signals sent by the sensor nodes, and to perform verification, decoding and summarization processing on the demodulated data. The host computer is used to receive and display the data uploaded by the coordinator node, and to send control commands to the coordinator node; The coordinator node modulates the control command and forwards it to the corresponding sensor node, and the corresponding sensor node performs the corresponding operation according to the control command. The sensor node includes a sensing element, a first communication component, a power management unit, and a controller; Sensing elements are used to collect monitoring data in real time and output analog or digital signals. The first communication component includes a baseband GMSK modem, an analog front-end, and an antenna. The baseband GMSK modem is used to perform GMSK modulation on the data to be transmitted and GMSK demodulation on the received signal. The analog front-end is used to filter, amplify, and up-convert the modulated analog signal, and to down-convert, filter, and amplify the received radio frequency signal. The antenna is used to convert the radio frequency signal processed by the analog front-end into electromagnetic waves for transmission, and to receive electromagnetic waves in space and convert them into radio frequency signals. The controller includes a low-power microprocessor, a sleep timer driven by an RC oscillator, and a wake-up interrupt circuit; the low-power processor is used to control data acquisition, simplified binary encoding, and instruction parsing and execution; the sleep timer is used for sleep-wake scheduling of communication components; The sensor node is configured with two clock sources: one is a 32MHz crystal oscillator, which drives a 32-bit counter to generate the local clock of the sensor node, providing a high-precision time base during active communication, data acquisition and processing of the sensor node, and is used for time synchronization with the coordinator node, calculation of network reference clock estimates and transmit / receive timing control; the other is an RC oscillator, which drives a sleep timer, keeps working in deep sleep mode, and performs sleep cycle timing and wake-up triggering with low power consumption. The power management unit is used to provide power to the sensor nodes and upload alarm signals when the battery is low; the power management unit includes a lithium battery and a voltage monitoring circuit. The coordinator node includes a second communication component, a data processor, a memory, an interface, and a low-power clock monitoring circuit. The second communication component matches the parameters of the first communication component of the sensor node. The second communication component is used to receive and demodulate the GMSK signal of the sensor node, as well as to send modulation control commands to the sensor node. The data processor uses a microprocessor to perform CRC verification, decoding, and data aggregation on the demodulated data, process retransmission requests, allocate communication addresses for sensor nodes, and realize network management. The memory is used to temporarily store real-time monitoring data; The interface uses an Ethernet interface or an RS485 interface for wired connection to the host computer; A low-power clock monitoring circuit is used to remain operational while the coordinator node enters a deep sleep state to monitor for wake-up signals or emergency data in the channel, and to wake up the second communication component and data processor when a valid signal is detected.

[0027] In some embodiments, unlike the embodiments described above, at least one relay node is also included; Relay nodes are deployed in areas where wireless signals are obstructed to forward GMSK signals between sensor nodes and coordinator nodes; The relay node does not participate in data processing.

[0028] like Figure 2 As shown, the following are embodiments of the GMSK-based sensor low-power short-range communication method provided in this disclosure. This method and the GMSK-based sensor low-power short-range communication system in the above embodiments belong to the same inventive concept. For details not described in detail in the embodiments of the GMSK-based sensor low-power short-range communication method, please refer to the embodiments of the GMSK-based sensor low-power short-range communication system described above.

[0029] The method includes the following steps: S1. The sensor node awakens from deep hibernation, scans the channel and receives beacon frames periodically broadcast by the coordinator node, and establishes synchronization and network connection with the coordinator node. It should be noted that this step enables each node to join the network on demand and synchronize its time, providing a foundation for low-power communication, and allows nodes to calibrate their local clocks through beacon frames; S2. When the preset acquisition cycle is reached, the sensor node wakes up its sensing element to acquire raw monitoring data, and its controller performs simplified binary encoding on the raw monitoring data to generate the encoded data payload. It should be noted that this step significantly reduces the amount of data and lowers transmission energy consumption through quantitative compression and compact splicing, while retaining key information; S3. The first communication component of the sensor node performs GMSK modulation on the encoded data payload, generates a GMSK modulated signal, and sends it to the coordinator node through the antenna; It should be noted that this step uses GMSK modulation parameters optimized for short range to improve spectrum utilization efficiency and achieve low-power transmission. S4. The coordinator node listens to the channel and receives the GMSK modulated signal, performs GMSK demodulation to obtain the demodulated data, and verifies the correctness of the demodulated data. It should be noted that this step involves multi-level verification to ensure data integrity and rapid retransmission in case of errors, thereby improving system reliability. S5. The coordinator node decodes and summarizes the verified demodulated data, uploads it to the host computer via communication cable, and receives control commands from the host computer. It then modulates the control commands and forwards them to the corresponding sensor nodes. It should be noted that this step enables data aggregation and two-way interaction, allowing the host computer to monitor and remotely control the sensor nodes in real time. S6. After completing a single data transmission or command interaction, both the sensor node and the coordinator node enter a deep sleep state, maintaining only low-power clock listening, and are woken up in the next preset acquisition cycle or when a wake-up command is received, returning to step S2. It should be noted that this step reduces standby power consumption through deep sleep, improves battery life in sensor nodes, and ensures communication stability through synchronous compensation after wake-up.

[0030] This embodiment replaces LoRa with GMSK modulation and optimizes the short-range architecture, achieving anti-interference communication, autonomous controllability, and long battery life in industrial scenarios such as power distribution rooms, thereby reducing operation and maintenance costs.

[0031] Furthermore, as a refinement and extension of the specific implementation of the above embodiments, in order to fully illustrate the specific implementation process of this embodiment, another low-power short-range sensor communication method based on GMSK is provided, which includes the following steps: S1. The sensor node awakens from deep hibernation, scans the channel and receives beacon frames periodically broadcast by the coordinator node, and establishes synchronization and network connection with the coordinator node. The specific steps of step S1 are as follows: S11. The sensor node automatically wakes up when the built-in sleep timer reaches the preset sleep period, or wakes up after receiving an external wake-up signal. After waking up, the sensor node scans the channel. S12. The coordinator node periodically broadcasts beacon frames, the beacon frames containing the network reference clock (NTB) timestamp of the coordinator node's local clock; S13. The sensor node calculates an estimate of the network reference clock by parsing the timestamp in the received beacon frame and combining it with its local clock. :

[0032] in, This is the local clock value when the sensor node finishes receiving the beacon frame. Send timestamps for the coordinator nodes carried in the beacon frames. The arrival time of the beacon frame is recorded locally by the sensor node; The local clock of the sensor node is implemented by a 32-bit counter driven by a 32MHz crystal oscillator; S14. Sensor node estimation based on network reference clock Establish time synchronization with the coordinator node and use an estimate of the network reference clock. Compensation calibration is performed on the sleep timer driven by the RC oscillator; S2. When the preset acquisition cycle is reached, the sensor node wakes up its sensing element to acquire raw monitoring data, and its controller performs simplified binary encoding on the raw monitoring data to generate the encoded data payload. The specific steps of step S2 are as follows: S21. When the preset acquisition period is reached, the controller of the sensor node wakes up the sensing element to acquire raw monitoring data in real time. The sensing element includes at least one of a smoke detector, a temperature and humidity sensor, a lighting control relay, or a photovoltaic status sensor. S22. The controller processes the raw monitoring data. The analog sensor data is quantized according to a preset precision P and converted into an N-bit binary number, where:

[0033] The controller will process the raw monitoring data. The data from the switching sensor is encoded as a 1-bit binary status flag. S23. All encoded data are concatenated in binary format according to a preset compact frame format, and redundant information is removed to generate encoded data payload; S3. The first communication component of the sensor node performs GMSK modulation on the encoded data payload, generates a GMSK modulated signal, and sends it to the coordinator node through the antenna; The specific steps of step S3 are as follows: S31. The first communication component of the sensor node performs GMSK modulation on the encoded data payload. The modulation parameters include the operating frequency band, preset Gaussian filter parameters, modulation index, channel bandwidth, and modulation rate corresponding to the signal bandwidth. Specifically, the operating frequency band is set to the 433MHz ISM band, and the product of the Gaussian filter bandwidth and the bit period is set to BT=0.5 to ensure that the signal spectrum meets the adjacent channel suppression requirement; the modulation index is set to 0.5; bit 0 represents negative frequency offset, and bit 1 represents positive frequency offset; the physical channel bandwidth is set to 200kHz or 400kHz, corresponding to modulation rates of 120K baud or 240K baud, and corresponding symbol periods of 1 / 120000 second or 1 / 240000 second, respectively. S32. The modulated GMSK signal is framed according to the physical layer radio frame format, wherein the physical layer radio frame includes a preamble, a start-of-frame symbol, a physical frame header (PHR), and a physical layer service data unit (PSDU) in sequence; the start-of-frame symbol is used to indicate whether forward error correction is performed on the physical frame header (PHR) and the physical layer service data unit (PSDU). The preamble consists of an alternating sequence of specific bits and lasts for a preset duration; the preamble consists of alternating sequences of 0 and 1 bits and lasts for 20 microseconds. The frame start symbol includes a first preset sequence and a second preset sequence. The first preset sequence indicates that the subsequent Physical Frame Header (PHR) and Physical Layer Service Data Unit (PSDU) do not use forward error correction coding, and the second preset sequence indicates that the subsequent Physical Frame Header (PHR) and Physical Layer Service Data Unit (PSDU) use forward error correction coding. The frame start symbol is a 16-bit sequence, including a first sequence SFDO and a second sequence SFDI. The SFDO indicates that the subsequent PHR and PSDU do not use forward error correction coding, and the SFDI indicates that the subsequent PHR and PSDU use forward error correction coding at 1 / 2 bit rate. SFDO[0:15]=1001000001001110,SFDI[0:15]=011011110110001; The Physical Frame Header (PHR) includes a frame length indication field, a first check field, and a second check field, wherein the frame length indication field is used to indicate the data length of the Physical Layer Service Data Unit (PSDU). The Physical Frame Header (PHR) consists of 14 bits of information, 12 bits of CRC checksum, 5 bits of BCH(31,26) checksum, and an optional 6-bit all-zero convolutional code termination bit. The 14 bits of information include an 8-bit frame length field FLEN, which indicates the number of bytes in the PSDU. The value of FLEN ranges from 3 to 255. The Physical Layer Service Data Unit (PSDU) includes payload data and a third check field; The Physical Layer Service Data Unit (PSDU) consists of FLEN × 8 PSDU information bits, an optional 6-bit all-zero convolutional code termination bit, and The PSDU information bits consist of a 24-bit CRC24 checksum. S33. Identify the start-of-frame character and, when forward error correction is required, add forward error correction coding to the Physical Frame Header (PHR) and Physical Layer Service Data Unit (PSDU) before modulation. The forward error correction coding includes binary convolutional coding and interleaving coding. The binary convolutional coding uses a convolutional code with a code rate of 1 / 2 and a constraint length of 7. Its generator polynomial is:

[0034]

[0035] in, and These correspond to the generator polynomials of 171 and 133 in octal representation, respectively. The encoder outputs two bits for every one bit input, with the output order being the first bit to be output. The convolution result is then output. The convolution result; The row-column interleaving is 4×4 interleaving. The bit stream output by the convolutional coding is written into a 4x4 matrix in the order of rows (i.e., fill the first row first, then the second row, and so on). Then it is read out in the order of columns (i.e., read all rows of the first column first, then all rows of the second column, and so on) to achieve discretization of continuous errors. S34. The modulated and framed GMSK signal is processed by the analog front end and then transmitted to the coordinator node through the antenna; S4. The coordinator node listens to the channel and receives the GMSK modulated signal, performs GMSK demodulation to obtain the demodulated data, and verifies the correctness of the demodulated data. The specific steps of step S4 are as follows: S41. The coordinator node continuously monitors the channel. When it receives a GMSK modulated signal, it filters the GMSK modulated signal to remove interference signals, then amplifies it, and finally performs GMSK demodulation to obtain demodulated data. S42. The coordinator node performs a 12-bit CRC check and a 5-bit BCH(31,26) check on the physical frame header (PHR) in the demodulated data. The generator polynomial for a 12-bit CRC checksum is:

[0036] The generator polynomial for the 5-bit BCH(31,26) checksum is:

[0037] If the verification fails, discard the current frame and record the error; If the verification passes, proceed to step S43; S43. Extract the Physical Layer Service Data Unit (PSDU) from the FLEN field in the Physical Frame Header (PHR) and perform a 24-bit CRC24 check on the PSDU. The generator polynomial for a 24-bit CRC24 checksum is: ; If the verification is successful, the coordinator node will pass the demodulated data to the data processor as the verified data. If the verification fails, the coordinator node constructs and sends a retransmission instruction frame to the corresponding sensor node. S5. The coordinator node decodes and summarizes the verified demodulated data, uploads it to the host computer via communication cable, and receives control commands from the host computer. It then modulates the control commands and forwards them to the corresponding sensor nodes. The specific steps of step S5 are as follows: S51. The data processor of the coordinator node decodes the correctly verified demodulated data to recover the original monitoring data before the simplified binary encoding; S52. The data processor classifies and summarizes the decoded data, and stores it into memory according to the sensor node address and data type. S53. The coordinator node uploads the aggregated data to the host computer via Ethernet or RS485 interface in a wired manner for real-time display and monitoring. S54. The coordinator node receives control commands from the host computer, modulates the control commands using GMSK, and then wirelessly forwards them to the corresponding sensor nodes; the control commands include light control switch commands or data acquisition cycle adjustment commands. S6. After completing a single data transmission or command interaction, both the sensor node and the coordinator node enter a deep sleep state, maintaining only low-power clock listening, and are woken up in the next preset acquisition cycle or when a wake-up command is received, returning to step S2. The specific steps of step S6 are as follows: S61. After completing a single data transmission or command interaction, the sensor node enters a deep sleep state, the sensing element and the first communication component are powered off, the high-speed clock in the controller is powered off, and only the sleep timer and wake-up interrupt circuit driven by the RC oscillator continue to work. When the 32MHz crystal oscillator and its driven counter circuit in the controller are powered off, only the sleep timer and wake-up interrupt circuit driven by the RC oscillator remain operational. In deep sleep mode, the RC oscillator remains operational to maintain the sleep timer's count. When the sleep timer count reaches a preset threshold, the wake-up interrupt circuit generates a wake-up interrupt signal to restore power to the 32MHz crystal oscillator and its driven counter circuit. S62. The coordinator node simultaneously enters a deep sleep state, the second communication component is powered off, and only the low-power clock listening circuit is retained. S63. When the sleep timer count of the sensor node reaches the preset sleep cycle threshold. When this occurs, a wake-up interrupt is generated, power is restored, and the process returns to step S2; Alternatively, when the coordinator node hears a wake-up command from the host computer or emergency data from the sensor node, it wakes up the coordinator node and forwards the wake-up command to the corresponding sensor node. S64. After the sensor node wakes up, it uses an estimated value from the network reference clock. The frequency and phase of the 32MHz crystal oscillator of the local clock are synchronized, and the frequency drift of the RC oscillator caused by temperature or voltage changes during sleep is compensated, and the process returns to step S2.

[0038] In some embodiments, unlike the embodiments described above, the method further includes a step of time-slot scheduling of multiple sensor nodes by a coordinator node: S7. The coordinator node maintains a dynamic time slot allocation table and allocates uplink communication time slots to each sensor node that successfully joins the network. The coordinator node embeds time slot allocation information into periodically broadcast beacon frames; Each sensor node only sends the collected data within its allocated uplink communication time slot, and remains in deep sleep or only listens for broadcast messages during the remaining uplink communication time slots.

[0039] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0040] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A GMSK-based sensor low-power short-range communication system, characterized in that, It includes a coordinator node, a host computer, and at least one sensor node; The coordinator node is wirelessly connected to each sensor node to form a star-shaped wireless communication network, and the coordinator node is connected to the host computer via a communication cable. Sensor nodes are used to collect monitoring data, perform GMSK modulation on the monitoring data after simplified binary encoding to obtain GMSK signals, and send them to the coordinator nodes. The coordinator node is used to receive and demodulate the GMSK signals sent by the sensor nodes, and to perform verification, decoding and summarization processing on the demodulated data. The host computer is used to receive and display the data uploaded by the coordinator node, and to send control commands to the coordinator node; The coordinator node modulates the control command and forwards it to the corresponding sensor node, which then performs the corresponding operation based on the control command.

2. The GMSK-based sensor low power short range communication system according to claim 1, characterized in that, The sensor node includes a sensing element, a first communication component, a power management unit, and a controller; Sensing elements are used to collect monitoring data in real time and output analog or digital signals. The first communication component includes a baseband GMSK modem, an analog front end, and an antenna; the baseband GMSK modem is used for GMSK modulation of the data to be transmitted and GMSK demodulation of the received signal; The analog front end is used to filter, amplify, and upconvert the modulated analog signal, as well as to downconvert, filter, and amplify the received radio frequency signal; the antenna is used to convert the radio frequency signal processed by the analog front end into electromagnetic waves for transmission, and to receive electromagnetic waves in space and convert them into radio frequency signals. The controller includes a low-power microprocessor, a sleep timer driven by an RC oscillator, and a wake-up interrupt circuit; the low-power processor is used to control data acquisition, simplified binary encoding, and instruction parsing and execution; the sleep timer is used for sleep-wake scheduling of communication components; The power management unit is used to provide power to the sensor nodes and upload alarm signals when the battery is low; the power management unit includes a lithium battery and a voltage monitoring circuit.

3. The GMSK-based sensor low power short range communication system according to claim 1, characterized in that, The coordinator node includes a second communication component, a data processor, a memory, an interface, and a low-power clock monitoring circuit. The second communication component matches the parameters of the first communication component of the sensor node. The second communication component is used to receive and demodulate the GMSK signal of the sensor node, as well as to send modulation control commands to the sensor node. The data processor uses a microprocessor to perform CRC verification, decoding, and data aggregation on the demodulated data, process retransmission requests, allocate communication addresses for sensor nodes, and realize network management. The memory is used to temporarily store real-time monitoring data; The interface uses an Ethernet interface or an RS485 interface for wired connection to the host computer; A low-power clock monitoring circuit is used to remain operational while the coordinator node enters a deep sleep state to monitor for wake-up signals or emergency data in the channel, and to wake up the second communication component and data processor when a valid signal is detected.

4. The GMSK-based sensor low power short range communication system according to claim 1, characterized in that, It also includes at least one relay node; Relay nodes are deployed in areas where wireless signals are obstructed to forward GMSK signals between sensor nodes and coordinator nodes.

5. A GMSK-based sensor low-power short-range communication method applied to the system of any one of claims 1 to 4, characterized in that, Includes the following steps: S1. The sensor node awakens from deep hibernation, scans the channel and receives beacon frames periodically broadcast by the coordinator node, and establishes synchronization and network connection with the coordinator node. S2. When the preset acquisition cycle is reached, the sensor node wakes up its sensing element to acquire raw monitoring data, and its controller performs simplified binary encoding on the raw monitoring data to generate the encoded data payload. S3. The first communication component of the sensor node performs GMSK modulation on the encoded data payload, generates a GMSK modulated signal, and sends it to the coordinator node through the antenna; S4. The coordinator node listens to the channel and receives the GMSK modulated signal, performs GMSK demodulation to obtain the demodulated data, and verifies the correctness of the demodulated data. S5. The coordinator node decodes and summarizes the verified demodulated data, uploads it to the host computer via communication cable, and receives control commands from the host computer. It then modulates the control commands and forwards them to the corresponding sensor nodes. S6. After completing a single data transmission or command interaction, both the sensor node and the coordinator node enter a deep sleep state, maintaining only low-power clock monitoring, and are woken up in the next preset acquisition cycle or when a wake-up command is received, returning to step S2.

6. The GMSK-based sensor low power short range communication method of claim 5, wherein, The specific steps of step S1 are as follows: S11. The sensor node automatically wakes up when the built-in sleep timer reaches the preset sleep period, or wakes up after receiving an external wake-up signal. After waking up, the sensor node scans the channel. S12. The coordinator node periodically broadcasts beacon frames, the beacon frames containing the network reference clock (NTB) timestamp of the coordinator node's local clock; S13. The sensor node calculates an estimate of the network reference clock by resolving the time stamp in the received beacon frame in combination with its local clock : in, This is the local clock value when the sensor node finishes receiving the beacon frame. Send timestamps for the coordinator nodes carried in the beacon frames. The arrival time of the beacon frame is recorded locally by the sensor node; S14. Sensor node estimation based on network reference clock Establish time synchronization with the coordinator node and use an estimate of the network reference clock. Compensation calibration is performed on the sleep timer driven by the RC oscillator.

7. The GMSK-based low-power short-range sensor communication method according to claim 5, characterized in that, The specific steps of step S2 are as follows: S21. When the preset acquisition period is reached, the controller of the sensor node wakes up the sensing element to acquire raw monitoring data in real time. ; S22. The controller processes the raw monitoring data. The analog sensor data is quantized according to a preset precision P and converted into an N-bit binary number, where: The controller will process the raw monitoring data. The data from the switch sensor is encoded as a 1-bit binary status flag. S23. All encoded data are concatenated in binary format according to a preset compact frame format, and redundant information is removed to generate encoded data payload.

8. The GMSK-based low-power short-range sensor communication method according to claim 5, characterized in that, The specific steps of step S3 are as follows: S31. The first communication component of the sensor node performs GMSK modulation on the encoded data payload. The modulation parameters include the operating frequency band, preset Gaussian filter parameters, modulation index, channel bandwidth, and modulation rate corresponding to the signal bandwidth. S32. The modulated GMSK signal is framed according to the physical layer radio frame format, wherein the physical layer radio frame includes a preamble, a start-of-frame symbol, a physical frame header (PHR), and a physical layer service data unit (PSDU) in sequence; the start-of-frame symbol is used to indicate whether forward error correction is performed on the physical frame header (PHR) and the physical layer service data unit (PSDU). S33. Identify the start-of-frame character and, when forward error correction is required, add forward error correction coding to the Physical Frame Header (PHR) and Physical Layer Service Data Unit (PSDU) before modulation. The forward error correction coding includes binary convolutional coding and interleaving coding. S34. After being modulated and framed, the GMSK signal is processed by the analog front-end and then transmitted to the coordinator node through the antenna.

9. The GMSK-based low-power short-range sensor communication method according to claim 5, characterized in that, The specific steps of step S4 are as follows: S41. The coordinator node continuously monitors the channel. When it receives a GMSK modulated signal, it filters the GMSK modulated signal to remove interference signals, then amplifies it, and finally performs GMSK demodulation to obtain demodulated data. S42. The coordinator node performs a 12-bit CRC check and a 5-bit BCH(31,26) check on the physical frame header (PHR) in the demodulated data. If the verification fails, discard the current frame and record the error; If the verification passes, proceed to step S43; S43. Extract the Physical Layer Service Data Unit (PSDU) from the FLEN field in the Physical Frame Header (PHR) and perform a 24-bit CRC24 check on the PSDU. If the verification is successful, the coordinator node will pass the demodulated data to the data processor as the verified data. If the verification fails, the coordinator node constructs and sends a retransmission instruction frame to the corresponding sensor node. The specific steps of step S6 are as follows: S61. After completing a single data transmission or command interaction, the sensor node enters a deep sleep state, the sensing element and the first communication component are powered off, the high-speed clock in the controller is powered off, and only the sleep timer and wake-up interrupt circuit driven by the RC oscillator continue to work. S62. The coordinator node simultaneously enters a deep sleep state, the second communication component is powered off, and only the low-power clock listening circuit is retained. S63. When the sleep timer count of the sensor node reaches the preset sleep cycle threshold. When this occurs, a wake-up interrupt is generated, power is restored, and the process returns to step S2; Alternatively, when the coordinator node hears a wake-up command from the host computer or emergency data from the sensor node, it wakes up the coordinator node and forwards the wake-up command to the corresponding sensor node. S64. After the sensor node wakes up, it uses an estimated value from the network reference clock. Synchronize the local clock in terms of frequency and phase, and compensate for the frequency drift of the RC oscillator caused by temperature or voltage changes during sleep, then return to step S2.

10. The GMSK-based low-power short-range sensor communication method according to claim 6, characterized in that, It also includes the step of time slot scheduling for multiple sensor nodes by the coordinator node: S7. The coordinator node maintains a dynamic time slot allocation table and allocates uplink communication time slots to each sensor node that successfully joins the network. The coordinator node embeds time slot allocation information into periodically broadcast beacon frames; Each sensor node only sends the collected data within its allocated uplink communication time slot, and remains in deep sleep or only listens for broadcast messages during the remaining uplink communication time slots.

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