Star communication method and system of building Internet of Things based on time sequence isolation

Abstract

The invention relates to the technical field of wireless communication of the Internet of Things, in particular to a star communication method and system of the building Internet of Things based on time sequence isolation, and the method comprises the steps: constructing a communication time axis of radio frequency communication, dividing the communication time axis into a plurality of continuous communication cycles, and generating time domain segmentation configuration information of each communication cycle; wherein the time domain segmentation configuration information defines a beacon time period, a control time period, a report time period and a synchronization time period which are arranged in sequence. According to the invention, a communication time axis based on strict time sequence isolation is constructed, the terminal equipment is forced to lock a reporting function in a control time period by issuing a time period control flag bit in a beacon frame, the exclusive access of a control instruction to channel resources is realized, the mechanism eliminates the interference of an uplink data stream to a downlink control instruction, and the performance of the terminal equipment is improved. Uncontrollable delay in the prior art is reduced to deterministic time slot transmission, and the problem that in the prior art, the control success rate is low under high concurrency is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of Internet of Things (IoT) wireless communication technology, specifically to a star-shaped communication method and system for building IoT based on time-series isolation. Background Technology

[0002] With the continuous improvement of building intelligence, the deployment of IoT devices such as smart lighting, environmental monitoring, and energy management within building spaces is showing a trend of large-scale and high-density deployment. To achieve interconnectivity and remote control of these massive numbers of terminal devices, the industry currently mainly uses wireless communication technologies such as LoRaWAN, BLE Mesh, and Zigbee as the underlying network. While these technologies have played an important role in their respective typical application scenarios, they still face insurmountable communication bottlenecks when dealing with the specific high-density, high-interference, and high-reliability control requirements of building IoT.

[0003] The limitations of existing mainstream technologies in high-density building scenarios are mainly reflected in the following three aspects: First, although LoRaWAN technology has a wide coverage, its transmission rate is usually lower than 5kbps, and the downlink control window only opens after uplink transmission. Uplink and downlink share channel resources, resulting in control command latency of more than 500ms when devices report concurrently, and the success rate drops to 82%, which is difficult to meet the reliability requirements of critical services such as fire alarm linkage. Second, BLE Mesh technology is based on the 2.4GHz frequency band, which has weak penetration ability through building walls. In addition, it adopts a publish / subscribe mode, with uplink and downlink logically mixed and no physical channel isolation. When deployed at high density, the message collision probability exceeds 15%, and the control success rate is lower than 95%. Finally, the superframe structure of Zigbee technology allows mixed uplink and downlink transmission during the CAP period and lacks a hard isolation mechanism. When the device density exceeds 50 units / 1000㎡, its CSMA-CA collision avoidance mechanism basically fails, resulting in the control latency jitter range expanding to 200-2000ms, which seriously affects the user experience. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution: a star-shaped communication method for building IoT based on time-series isolation, the method being applied to a communication system including a gateway, terminal devices, and repeaters, comprising:

[0005] A communication timeline for radio frequency communication is constructed, the communication timeline is divided into multiple consecutive communication cycles, and time-domain segmentation configuration information for each communication cycle is generated; wherein, the time-domain segmentation configuration information defines a beacon time period, a control time period, a reporting time period, and a synchronization time period arranged in sequence, and defines the mutual exclusion activation logic between the control time period and the reporting time period;

[0006] Acquire the spectral interference characteristic data of the current building environment, and combine it with the preset building wall penetration attenuation model to perform signal-to-noise ratio prediction analysis on the spectral interference characteristic data, and generate a future periodic frequency band allocation list.

[0007] The future period frequency band allocation list is encapsulated into a beacon frame and broadcast through the gateway during the beacon period;

[0008] The downlink command queue of the gateway is monitored in real time, and a time period control flag is generated according to the status of the downlink command queue. The time period control flag is written into the beacon frame to instruct the terminal device to activate the control time period and forcibly block the reporting time period, so as to realize the exclusive use of channel resources by the control command.

[0009] When the time period control flag indicates that the control time period is invalid, the reporting time period is activated; during the reporting time period, the real-time signal strength value of the current working channel is obtained, the real-time signal strength value is compared with the building interference threshold, and a channel occupancy decision result is generated; random avoidance or data transmission operation is performed according to the channel occupancy decision result.

[0010] During the synchronization period, a synchronization guidance frame is generated based on a preset dual-frequency redundancy strategy; when the terminal device is detected to be out of contact, the terminal device is guided to the working channel specified in the future period frequency band allocation list through the synchronization guidance frame.

[0011] Preferably, the signal-to-noise ratio prediction analysis is performed on the spectral interference feature data to generate a future periodic frequency band allocation list, including:

[0012] After the synchronization period ends, a full-band scan of all working channels is triggered to obtain the interference power spectral density of each channel.

[0013] The building wall penetration attenuation model is invoked to calculate the penetration loss value based on the floor topology difference between the terminal device and the gateway;

[0014] Based on the interference power spectral density and the penetration loss value, calculate the expected received signal-to-noise ratio of each channel in the next communication cycle and the communication cycle after that;

[0015] The two channels with the highest expected received signal-to-noise ratio are selected as the first working channel number and the second working channel number, respectively, to form the future periodic frequency band allocation list.

[0016] Preferably, the downlink command queue of the gateway is monitored in real time, and a time period control flag is generated based on the status of the downlink command queue, including:

[0017] Determine whether there are any instructions to be sent in the downlink instruction queue;

[0018] If present, the control valid bit in the beacon frame is set, and a command time slot is allocated during the control period;

[0019] Send control commands within the instruction time slot and start the cross-cycle retransmission counter;

[0020] Monitor whether an acknowledgment frame is received from the terminal device within a preset time.

[0021] If not received, the instruction is retransmitted during the control period of the next communication cycle, and the cross-cycle retransmission counter is incremented until an acknowledgment frame is received or the counter reaches the maximum retransmission threshold.

[0022] The maximum retransmission threshold is set to 32 times to ensure the reliability of instruction delivery in complex building environments.

[0023] Preferably, based on the channel occupancy decision result, a random avoidance or data transmission operation is performed to generate an uplink data feedback stream, including:

[0024] After entering the reporting period, a random avoidance window is started, and the real-time signal strength value of the current working channel is continuously monitored within the window;

[0025] If the monitored real-time signal strength value exceeds the building interference threshold, it is determined that the channel is occupied, the current reporting opportunity is abandoned and the channel enters a dormant state until the next reporting slot restarts random avoidance.

[0026] If the monitored real-time signal strength value is lower than the building interference threshold, the channel is determined to be idle, an uplink data frame is immediately sent, and an acknowledgment waiting timer is started.

[0027] If no feedback is received before the confirmation waiting timer expires, the number of failures is recorded and the above monitoring steps are repeated in the next reporting slot until the transmission is successful or the maximum number of retries is reached.

[0028] Preferably, the building interference threshold is preset through the following calibration steps:

[0029] Multiple test terminal devices were deployed in the target building environment to measure the statistical mapping relationship between data packet reception rate and signal strength value under interference-free and congestion conditions.

[0030] Obtain the signal strength value corresponding to the data packet reception rate dropping to a preset percentage threshold;

[0031] The corresponding signal strength value is set as the building interference threshold.

[0032] Preferably, generating a synchronization guidance frame based on a preset dual-frequency redundancy strategy includes:

[0033] The gateway is configured with two fixed synchronization frequencies, and during the synchronization period of each communication cycle, it alternately uses these two synchronization frequencies to send a synchronization guide frame containing the working channel number of the next communication cycle.

[0034] When the terminal device detects a power failure and restart or fails to receive a beacon frame for two consecutive communication cycles, it enters a synchronous reception state and listens alternately on the two synchronous frequency points.

[0035] After capturing the synchronization guide frame, the terminal device parses out the working channel number for the next communication cycle and immediately switches to that working channel to wait for the beacon frame.

[0036] Preferably, the method further includes:

[0037] Configure the radio frequency protocol stack parameters of the repeater to keep them mirrored with the frequency hopping architecture and beacon format of the gateway;

[0038] The repeater receives uplink and downlink data frames at the physical layer and performs data relay based on a transparent forwarding mechanism without parsing the application layer payload.

[0039] The gateway records device ownership relationships through a logical management layer and centrally controls the data routing transmitted via the repeater.

[0040] A star communication system for building IoT based on time-series isolation, applicable to the aforementioned star communication method for building IoT based on time-series isolation, includes:

[0041] A communication time axis construction module is used to construct a communication time axis for radio frequency communication, divide the communication time axis into multiple consecutive communication cycles, and generate time domain segmentation configuration information for each communication cycle; wherein, the time domain segmentation configuration information defines a beacon time period, a control time period, a reporting time period, and a synchronization time period arranged in sequence, and defines the mutual exclusion activation logic between the control time period and the reporting time period;

[0042] The frequency band prediction and allocation module is used to acquire the spectrum interference characteristic data of the current building environment, and combine it with the preset building wall penetration attenuation model to perform signal-to-noise ratio prediction analysis on the spectrum interference characteristic data to generate a future period frequency band allocation list.

[0043] The beacon encapsulation broadcast module is used to encapsulate the future period frequency band allocation list into a beacon frame and broadcast it through the gateway during the beacon period;

[0044] The time-period mutual exclusion control module is used to monitor the downlink command queue of the gateway in real time, generate a time-period control flag bit according to the status of the downlink command queue, write the time-period control flag bit into the beacon frame, instruct the terminal device to activate the control time period and forcibly block the reporting time period, so as to realize the exclusive use of channel resources by the control command;

[0045] The uplink avoidance reporting module is used to activate the reporting period when the time period control flag indicates that the control period is invalid; during the reporting period, it acquires the real-time signal strength value of the current working channel, compares the real-time signal strength value with the building interference threshold, and generates a channel occupancy decision result; and performs random avoidance or data transmission operation according to the channel occupancy decision result.

[0046] The dual-frequency synchronization guidance module is used to generate a synchronization guidance frame based on a preset dual-frequency redundancy strategy during the synchronization period; when the terminal device is detected to be out of contact, the synchronization guidance frame is used to guide the terminal device to the working channel specified in the future period frequency band allocation list.

[0047] The relay transparent forwarding module is used to configure the radio frequency protocol stack parameters of the repeater to keep them mirrored with the gateway, and to receive uplink and downlink data frames at the physical layer. Without parsing the application layer payload, it performs data relay based on the transparent forwarding mechanism.

[0048] Compared with the prior art, the beneficial effects of the present invention are:

[0049] (1) This invention constructs a communication timeline based on strict time-series isolation. By sending a time-series control flag in the beacon frame, the terminal device is forced to lock the reporting function during the control period, thereby realizing exclusive access of the channel resources by the control command. This mechanism eliminates the interference of the uplink data stream on the downlink control command, reduces the uncontrollable delay in the prior art to deterministic time-slot transmission, and effectively solves the pain point of low control success rate under high concurrency in the prior art.

[0050] (2) This invention introduces a building wall penetration attenuation model and signal-to-noise ratio prediction analysis; the system does not passively switch after encountering interference, but actively calculates and selects the working channel with the best expected signal-to-noise ratio in the next two cycles based on the floor topology difference and the current spectrum interference characteristics; this active spectrum strategy improves the signal penetration ability of the floor and walls, and ensures the stability of the communication link in cross-floor and complex obstruction environments.

[0051] (3) The present invention adopts a dual strategy of centralized scheduling + random avoidance. On the gateway side, the time period is uniformly scheduled through beacons; on the terminal side, a random avoidance window and interference threshold judgment are introduced during the reporting time period. This mechanism effectively disperses the data storm generated by concurrent reporting, reduces the probability of data packet collision in the air, and can maintain a high uplink throughput and access success rate even when the equipment is deployed at high density.

[0052] (4) This invention designs a dual-frequency redundant synchronous guidance mechanism. When the terminal device experiences a power outage and restart or loses connection, it can quickly find the network by polling two fixed synchronous frequencies, thus avoiding long-term offline time caused by single-point failure. At the same time, combined with the optional transparent forwarding mechanism of the repeater, the signal coverage range is extended while maintaining the consistency of the timing architecture, thus solving the communication dead zone problem in large buildings. Attached Figure Description

[0053] Figure 1 This is a schematic flowchart of the overall method in one embodiment of the present invention;

[0054] Figure 2 This is a schematic diagram of the overall system architecture in one embodiment of the present invention.

[0055] In the diagram: 1. Communication timeline construction module; 2. Frequency band prediction and allocation module; 3. Beacon encapsulation and broadcast module; 4. Time period mutual exclusion control module; 5. Uplink avoidance and reporting module; 6. Dual-frequency synchronization guidance module; 7. Relay transparent forwarding module. Detailed Implementation

[0056] 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.

[0057] Example 1, please refer to Figure 1 This invention provides a technical solution: a star communication method for building IoT based on time-series isolation, comprising:

[0058] S1. Construct the communication time axis for radio frequency communication, divide the communication time axis into multiple consecutive communication cycles, and generate time-domain segmentation configuration information for each communication cycle; wherein, the time-domain segmentation configuration information defines the beacon time period, control time period, reporting time period and synchronization time period arranged in sequence, and defines the mutual exclusion activation logic between the control time period and the reporting time period.

[0059] S2. Obtain the spectrum interference characteristic data of the current building environment, and combine it with the preset building wall penetration attenuation model to perform signal-to-noise ratio prediction analysis on the spectrum interference characteristic data, and generate a future periodic frequency band allocation list.

[0060] S3. Encapsulate the future period frequency band allocation list into the beacon frame and broadcast it through the gateway during the beacon period;

[0061] S4. Monitor the downlink command queue of the gateway in real time, generate a time period control flag based on the status of the downlink command queue, and write the time period control flag into the beacon frame to instruct the terminal device to activate the control time period and forcibly block the reporting time period, so as to realize the exclusive use of channel resources by the control command.

[0062] S5. When the time period control flag indicates that the control time period is invalid, activate the reporting time period; during the reporting time period, obtain the real-time signal strength value of the current working channel, compare the real-time signal strength value with the building interference threshold, and generate a channel occupancy decision result; perform random avoidance or data transmission operation according to the channel occupancy decision result.

[0063] S6. During the synchronization period, a synchronization guidance frame is generated based on a preset dual-frequency redundancy strategy. When the terminal device is detected to be out of contact, the terminal device is guided to the working channel specified in the future period frequency band allocation list through the synchronization guidance frame.

[0064] It should be noted that the communication timeline in this embodiment is the core synchronization reference of the system. In a typical building application scenario, the total duration of a single communication cycle is set to 410ms. The specific time-domain segmentation configuration is as follows: beacon period (10ms), control period (70ms), reporting period (210ms), and synchronization period (120ms). The so-called mutual exclusion activation logic refers to the gateway dynamically scheduling the radio frequency state of the terminal through a specific flag bit Flag in the beacon frame. When Flag=1 (control priority mode), all terminal devices must forcibly shut down their transmitting circuits and only maintain the receiving state to wait for the gateway's instructions, thereby eliminating the interference of uplink data on downlink control commands at the physical layer. When Flag=0 (normal mode), the terminal device is allowed to enter the reporting period to compete for transmission. This mechanism solves the problem of large control command latency in traditional Zigbee or LoRaWAN in concurrent scenarios.

[0065] In an optional embodiment, signal-to-noise ratio prediction analysis is performed on spectral interference characteristic data to generate a future periodic frequency band allocation list, including:

[0066] After the synchronization period ends, a full-band scan of all working channels is triggered to obtain the interference power spectral density of each channel.

[0067] The building wall penetration attenuation model is invoked to calculate the penetration loss value based on the floor topology difference between the terminal device and the gateway;

[0068] Based on the interference power spectral density and penetration loss value, the expected received signal-to-noise ratio of each channel in the next communication cycle and the next communication cycle after that is calculated.

[0069] The two channels with the highest expected received signal-to-noise ratio are selected as the first working channel number and the second working channel number, respectively, to form a future periodic frequency band allocation list.

[0070] It should be noted that this system employs refined frequency band planning, dividing the 433MHz band into 24 working channels (channel spacing 125kHz); the building wall penetration attenuation model typically uses the following empirical formula:

[0071] ;

[0072] in, The reference path loss is the signal loss value measured at a nearby reference point. The path loss index reflects the degree of influence of the environment on signal attenuation. It is usually taken as 2.0 to 3.0 in a building line-of-sight environment and 3.0 to 5.0 in a non-line-of-sight environment with obstructions. This refers to the straight-line geometric distance between the transmitter and receiver, i.e., the straight-line geometric distance between the gateway and the terminal device. This is the floor penetration factor (usually taken as 15dB-20dB). The difference between the gateway and the terminal is the floor level; the system does not only select the cleanest channel at present, but also predicts the signal-to-noise ratio of the next cycle and the cycle after that; the purpose of selecting two channels to put in the allocation list is to provide redundancy: the terminal device first selects the first working channel, and if the first channel suddenly experiences severe interference that causes the beacon to be lost, the terminal can immediately try to switch to the second working channel without having to re-enter the long synchronization search process.

[0073] In an optional embodiment, the downlink command queue of the gateway is monitored in real time, and a time period control flag is generated based on the status of the downlink command queue, including:

[0074] Determine if there are any pending commands in the downlink command queue;

[0075] If present, the control valid bit in the beacon frame will be set, and command time slots will be allocated during the control period;

[0076] Send control commands within the command time slot and start the cross-cycle retransmission counter;

[0077] Monitor whether an acknowledgment frame is received from the terminal device within a preset time.

[0078] If not received, the instruction is retransmitted during the control period of the next communication cycle, and the cross-cycle retransmission counter is incremented until an acknowledgment frame is received or the counter reaches the maximum retransmission threshold.

[0079] The maximum retransmission threshold is set to 32 times to ensure the reliability of instruction delivery in complex building environments.

[0080] It should be noted that this embodiment has made in-depth optimizations to the reliability of control commands. Specifically, the system subdivides the 70ms control period into seven 10ms command slots, allowing the gateway to issue a maximum of seven commands at a time to avoid channel congestion. At the same time, based on the MCU processing speed and RF transceiver switching time, the preset confirmation waiting time is set to an optimal value of 5ms. In the cross-cycle retransmission mechanism, the gateway keeps the frame sequence number of the command unchanged when retransmitting, but updates the cycle sequence number, so that the terminal device can accurately identify the retransmitted frame and prevent repeated execution due to ACK loss. In addition, considering that there may be strong motor interference in the building, such as elevator starting, which lasts for several seconds, the system sets the maximum retransmission threshold to 32 times (approximately 13 seconds). This setting can effectively cover most instantaneous interference cycles and ensure that critical control commands are delivered.

[0081] In an optional embodiment, a random avoidance or data transmission operation is performed based on the channel occupancy decision result to generate an uplink data feedback stream, including:

[0082] After entering the reporting period, a random avoidance window is started, and the real-time signal strength value of the current working channel is continuously monitored within the window;

[0083] If the monitored real-time signal strength value exceeds the building interference threshold, it is determined that the channel is occupied, the current reporting opportunity is abandoned and the channel enters a dormant state until the next reporting slot restarts and randomly avoids interference.

[0084] If the monitored real-time signal strength value is lower than the building interference threshold, the channel is determined to be idle, an uplink data frame is immediately sent, and an acknowledgment waiting timer is started.

[0085] If no feedback is received before the confirmation waiting timer expires, the number of failures is recorded and the above monitoring steps are repeated in the next reporting slot until the message is successfully sent or the maximum number of retries is reached.

[0086] It should be noted that the duration of the random avoidance window is randomly generated between 1ms and 25ms, which can effectively disperse the concurrent collisions caused by hundreds of terminals being woken up at the same time; giving up the current reporting opportunity is an aggressive energy-saving strategy: once channel congestion is detected, the device does not continue to listen, but directly goes to sleep to the next time slot to maximize battery life; the building interference threshold is specifically set to -85dBm in this embodiment, which is the key dividing line for distinguishing effective signals from background noise / adjacent channel interference.

[0087] In an optional embodiment, the building interference threshold is preset through the following calibration steps:

[0088] Multiple test terminal devices were deployed in the target building environment to measure the statistical mapping relationship between data packet reception rate and signal strength value under interference-free and congestion conditions.

[0089] Obtain the signal strength value corresponding to the data packet reception rate dropping to a preset percentage threshold;

[0090] Set the corresponding signal strength value as the building interference threshold.

[0091] It should be noted that in actual testing, we found that when the ambient noise floor is higher than -85dBm, the bit error rate of FSK modulation and demodulation packets will rise sharply from 0.1% to more than 1% (i.e., the preset percentage threshold). Therefore, locking the threshold at -85dBm can filter out most of the background noise without causing insufficient channel utilization due to an excessively low threshold.

[0092] In an optional embodiment, generating a synchronization guidance frame based on a preset dual-frequency redundancy strategy includes:

[0093] The gateway is configured with two fixed synchronization frequencies, and during the synchronization period of each communication cycle, it alternately uses these two synchronization frequencies to send a synchronization guide frame containing the working channel number of the next communication cycle.

[0094] When the terminal device detects a power failure and restart or fails to receive a beacon frame for two consecutive communication cycles, it enters the synchronous reception state and listens alternately on two synchronous frequency points.

[0095] After capturing the synchronization guide frame, the terminal device parses out the working channel number for the next communication cycle and immediately switches to that working channel to wait for the beacon frame.

[0096] It should be noted that the system has two dedicated synchronization frequencies preset, such as 433.00MHz and 436.10MHz, located at the beginning and end of the frequency band respectively, to obtain the maximum frequency diversity gain. Alternating use means that the gateway uses 433.00MHz to send synchronization frames in period N and 436.10MHz in period N+1. This ensures that even if a frequency is subject to continuous single-frequency interference, the terminal device can find the network again through the other frequency within two periods (about 0.8 seconds), which greatly improves the system's self-healing capability.

[0097] In an optional embodiment, the method further includes:

[0098] Configure the repeater's radio frequency protocol stack parameters to ensure they mirror the gateway's frequency hopping architecture and beacon format;

[0099] The repeater receives uplink and downlink data frames at the physical layer and performs data relay based on a transparent forwarding mechanism without parsing the application layer payload.

[0100] The gateway records device ownership relationships through a logical management layer and centrally controls the routing of data transmitted via repeaters.

[0101] It should be noted that the repeater in this embodiment differs from traditional network layer routing devices. It operates at the physical link layer; mirror consistency means that the repeater has the exact same frequency hopping schedule and beacon transmission logic as the gateway; the transparent forwarding mechanism means that after receiving the RF signal, the repeater only performs cyclic redundancy check, without decrypting or parsing specific application layer instructions, such as turning a light on or off, and directly remodulates and transmits the RF signal in the corresponding time slot; this design results in extremely low processing latency for the repeater and eliminates the need to store a large number of device keys, ensuring system security and low cost. The gateway determines whether to use the repeater to reach terminals in blind spots by recording the topology relationship between device IDs and repeaters.

[0102] Example 2, please refer to Figure 2 This invention provides a technical solution: a star communication system for building IoT based on time-series isolation, applicable to the aforementioned star communication method for building IoT based on time-series isolation, comprising:

[0103] The communication time axis construction module 1 is used to construct the communication time axis of radio frequency communication, divide the communication time axis into multiple consecutive communication cycles, and generate time domain segmentation configuration information for each communication cycle; wherein, the time domain segmentation configuration information defines the beacon time period, control time period, reporting time period and synchronization time period arranged in sequence, and defines the mutual exclusion activation logic of the control time period and the reporting time period.

[0104] The frequency band prediction and allocation module 2 is used to acquire the spectrum interference characteristic data of the current building environment, and combine it with the preset building wall penetration attenuation model to perform signal-to-noise ratio prediction analysis on the spectrum interference characteristic data to generate a future period frequency band allocation list.

[0105] Beacon Encapsulation Broadcast Module 3 is used to encapsulate the future periodic frequency band allocation list into beacon frames and broadcast them through the gateway during the beacon period;

[0106] The time period mutual exclusion control module 4 is used to monitor the downlink command queue of the gateway in real time, generate a time period control flag bit according to the status of the downlink command queue, write the time period control flag bit into the beacon frame, instruct the terminal device to activate the control time period and forcibly block the reporting time period, so as to realize the exclusive use of channel resources by the control command;

[0107] The uplink avoidance reporting module 5 is used to activate the reporting period when the time period control flag indicates that the control period is invalid; during the reporting period, it obtains the real-time signal strength value of the current working channel, compares the real-time signal strength value with the building interference threshold, and generates a channel occupancy decision result; and performs random avoidance or data transmission operation according to the channel occupancy decision result.

[0108] The dual-frequency synchronization guidance module 6 is used to generate a synchronization guidance frame based on a preset dual-frequency redundancy strategy during the synchronization period; when the terminal device is detected to be out of contact, the synchronization guidance frame guides the terminal device to the working channel specified in the future period frequency band allocation list.

[0109] The relay transparent forwarding module 7 is used to configure the radio frequency protocol stack parameters of the repeater to keep them mirrored with the gateway, and to receive uplink and downlink data frames at the physical layer. Without parsing the application layer payload, it performs data relay based on the transparent forwarding mechanism.

[0110] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A star communication method for building IoT based on time-series isolation, characterized in that, The method is applied to a communication system including a gateway, terminal equipment, and repeaters, including: A communication timeline for radio frequency communication is constructed, the communication timeline is divided into multiple consecutive communication cycles, and time-domain segmentation configuration information for each communication cycle is generated; wherein, the time-domain segmentation configuration information defines a beacon time period, a control time period, a reporting time period, and a synchronization time period arranged in sequence, and defines the mutual exclusion activation logic between the control time period and the reporting time period; Acquire the spectral interference characteristic data of the current building environment, and combine it with the preset building wall penetration attenuation model to perform signal-to-noise ratio prediction analysis on the spectral interference characteristic data, and generate a future periodic frequency band allocation list. The future period frequency band allocation list is encapsulated into a beacon frame and broadcast through the gateway during the beacon period; The downlink command queue of the gateway is monitored in real time, and a time period control flag is generated according to the status of the downlink command queue. The time period control flag is written into the beacon frame to instruct the terminal device to activate the control time period and forcibly block the reporting time period, so as to realize the exclusive use of channel resources by the control command. When the time period control flag indicates that the control time period is invalid, the reporting time period is activated; during the reporting time period, the real-time signal strength value of the current working channel is obtained, the real-time signal strength value is compared with the building interference threshold, and a channel occupancy decision result is generated; random avoidance or data transmission operation is performed according to the channel occupancy decision result. During the synchronization period, a synchronization guidance frame is generated based on a preset dual-frequency redundancy strategy; when the terminal device is detected to be out of contact, the terminal device is guided to the working channel specified in the future period frequency band allocation list through the synchronization guidance frame.

2. The star-shaped communication method for building IoT based on time-series isolation according to claim 1, characterized in that, The signal-to-noise ratio (SNR) prediction analysis is performed on the spectral interference characteristic data to generate a future periodic frequency band allocation list, including: After the synchronization period ends, a full-band scan of all working channels is triggered to obtain the interference power spectral density of each channel. The building wall penetration attenuation model is invoked to calculate the penetration loss value based on the floor topology difference between the terminal device and the gateway; Based on the interference power spectral density and the penetration loss value, calculate the expected received signal-to-noise ratio of each channel in the next communication cycle and the communication cycle after that; The two channels with the highest expected received signal-to-noise ratio are selected as the first working channel number and the second working channel number, respectively, to form the future periodic frequency band allocation list.

3. The star-shaped communication method for building IoT based on time-series isolation according to claim 1, characterized in that, Real-time monitoring of the downlink command queue of the gateway, and generation of time-period control flags based on the status of the downlink command queue, including: Determine whether there are any instructions to be sent in the downlink instruction queue; If present, the control valid bit in the beacon frame is set, and a command time slot is allocated during the control period; Send control commands within the command time slot and start the cross-cycle retransmission counter; Monitor whether an acknowledgment frame is received from the terminal device within a preset time. If not received, the instruction is retransmitted during the control period of the next communication cycle, and the cross-cycle retransmission counter is incremented until an acknowledgment frame is received or the counter reaches the maximum retransmission threshold. The maximum retransmission threshold is set to 32 times to ensure the reliability of instruction delivery in complex building environments.

4. The star-shaped communication method for building IoT based on time-series isolation according to claim 1, characterized in that, Based on the channel occupancy decision result, perform random avoidance or data transmission operations to generate an uplink data feedback stream, including: After entering the reporting period, a random avoidance window is started, and the real-time signal strength value of the current working channel is continuously monitored within the window; If the monitored real-time signal strength value exceeds the building interference threshold, it is determined that the channel is occupied, the current reporting opportunity is abandoned and the channel enters a sleep state until the next reporting slot restarts random avoidance. If the monitored real-time signal strength value is lower than the building interference threshold, the channel is determined to be idle, an uplink data frame is immediately sent, and an acknowledgment waiting timer is started. If no feedback is received before the confirmation waiting timer expires, the number of failures is recorded and the above monitoring steps are repeated in the next reporting slot until the transmission is successful or the maximum number of retries is reached.

5. The star-shaped communication method for building IoT based on time-series isolation according to claim 1, characterized in that, The building interference threshold is preset through the following calibration steps: Multiple test terminal devices were deployed in the target building environment to measure the statistical mapping relationship between data packet reception rate and signal strength value under interference-free and congestion conditions. Obtain the signal strength value corresponding to the data packet reception rate dropping to a preset percentage threshold; The corresponding signal strength value is set as the building interference threshold.

6. The star-shaped communication method for building IoT based on time-series isolation according to claim 1, characterized in that, A synchronization guide frame is generated based on a preset dual-frequency redundancy strategy, including: The gateway is configured with two fixed synchronization frequencies, and during the synchronization period of each communication cycle, it alternately uses these two synchronization frequencies to send a synchronization guide frame containing the working channel number of the next communication cycle. When the terminal device detects a power failure and restart or fails to receive a beacon frame for two consecutive communication cycles, it enters a synchronous reception state and listens alternately on the two synchronous frequency points. After capturing the synchronization guide frame, the terminal device parses out the working channel number for the next communication cycle and immediately switches to that working channel to wait for the beacon frame.

7. A star communication method for building IoT based on time-series isolation according to claim 1, characterized in that, The method further includes: Configure the radio frequency protocol stack parameters of the repeater to keep them mirrored with the frequency hopping architecture and beacon format of the gateway; The repeater receives uplink and downlink data frames at the physical layer and performs data relay based on a transparent forwarding mechanism without parsing the application layer payload. The gateway records device ownership relationships through a logical management layer and centrally controls the data routing transmitted via the repeater.

8. A star communication system for building IoT based on time-series isolation, applicable to the star communication method for building IoT based on time-series isolation as described in any one of claims 1-7, characterized in that, include: A communication time axis construction module is used to construct a communication time axis for radio frequency communication, divide the communication time axis into multiple consecutive communication cycles, and generate time domain segmentation configuration information for each communication cycle; wherein, the time domain segmentation configuration information defines a beacon time period, a control time period, a reporting time period, and a synchronization time period arranged in sequence, and defines the mutual exclusion activation logic between the control time period and the reporting time period; The frequency band prediction and allocation module is used to acquire the spectrum interference characteristic data of the current building environment, and combine it with the preset building wall penetration attenuation model to perform signal-to-noise ratio prediction analysis on the spectrum interference characteristic data to generate a future period frequency band allocation list. The beacon encapsulation broadcast module is used to encapsulate the future period frequency band allocation list into a beacon frame and broadcast it through the gateway during the beacon period; The time-period mutual exclusion control module is used to monitor the downlink command queue of the gateway in real time, generate a time-period control flag bit according to the status of the downlink command queue, write the time-period control flag bit into the beacon frame, instruct the terminal device to activate the control time period and forcibly block the reporting time period, so as to realize the exclusive use of channel resources by the control command; The uplink avoidance reporting module is used to activate the reporting period when the time period control flag indicates that the control period is invalid; during the reporting period, it acquires the real-time signal strength value of the current working channel, compares the real-time signal strength value with the building interference threshold, and generates a channel occupancy decision result; and performs random avoidance or data transmission operation according to the channel occupancy decision result. The dual-frequency synchronization guidance module is used to generate a synchronization guidance frame based on a preset dual-frequency redundancy strategy during the synchronization period; when the terminal device is detected to be out of contact, the synchronization guidance frame is used to guide the terminal device to the working channel specified in the future period frequency band allocation list. The relay transparent forwarding module is used to configure the radio frequency protocol stack parameters of the repeater to keep them mirrored with the gateway, and to receive uplink and downlink data frames at the physical layer. Without parsing the application layer payload, it performs data relay based on the transparent forwarding mechanism.

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