Method and protocol for conference minutes synchronization based on bluetooth low energy

Abstract

The present application relates to the technical field of conference minutes synchronization, and particularly relates to a conference minutes synchronization method and protocol based on Bluetooth low energy, which adds a metadata header containing a conference ID, a total data length, a size after compression, a CRC32 check value and a timestamp to compressed conference minutes data, intelligently packages the data according to a BLE MTU, and includes a packet sequence number, a total packet number, a payload and a CRC16 check value in each package; the data is sent by GATT in a sliding window, an ACK / NACK is replied by a receiver, and a timeout retransmission is supported; a breakpoint is saved when a connection is interrupted, and subsequent data is transmitted after reconnection; a state is pushed by BLE Notify, and a transmission progress is synchronously displayed on a hardware LCD and a mobile phone APP. The present application solves the problems of the existing Bluetooth low energy adaptation portable device, easy package loss of large-capacity conference minutes data transmission, no breakpoint continuation, lack of progress feedback, weak encryption capability, and unsynchronized transmission progress between a hardware device and a mobile phone APP.

Description

Technical Field

[0001] This invention relates to the field of meeting minutes synchronization technology, specifically to a meeting minutes synchronization method and protocol based on Bluetooth Low Energy. Background Technology

[0002] Bluetooth Low Energy (BLE) technology: BLE is a low-power wireless communication technology introduced in Bluetooth 4.0. It operates in the 2.4GHz ISM band, uses GFSK modulation, has a typical transmission distance of 10-100 meters, and a typical data rate of 125kbps-2Mbps.

[0003] Bluetooth Low Energy (BLE) technology boasts advantages such as low power consumption and low cost, making it ideal for battery-powered portable devices. However, BLE presents the following technical challenges when transferring large files:

[0004] (1) Packet loss problem: BLE's MTU is usually limited to 20-512 bytes. Meeting minutes data (including transcribed text, AI analysis results, and metadata) often exceeds 100KB, and can even reach several MB. BLE connection is unstable, and packet transmission is prone to loss.

[0005] (2) No interruption resume problem: The existing BLE transmission scheme lacks an interruption resume mechanism. After the connection is interrupted, the transmission needs to start from the beginning, which is inefficient.

[0006] (3) Lack of progress feedback: Users cannot perceive the transmission status, do not know whether the transmission is in progress or how much has been completed, which can easily cause anxiety and repetitive operations.

[0007] (4) Security issues: The meeting content involves trade secrets and needs to be transmitted in encrypted form. Existing BLE transmission mostly uses plaintext or simple encryption, which poses a high risk of data leakage.

[0008] (5) Poor hardware and software coordination: The transmission progress cannot be displayed on the hardware device and the mobile APP at the same time, and there is a lack of a unified status synchronization mechanism.

[0009] The present invention aims to solve the above-mentioned technical problems and provide an optimized transmission protocol suitable for specific scenarios of meeting minutes. Summary of the Invention

[0010] The technical problem this invention aims to solve is that existing Bluetooth Low Energy compatible portable devices are prone to packet loss when transmitting large amounts of meeting minutes data, lack interrupted transmission, lack progress feedback, have weak encryption capabilities, and the hardware device and mobile APP cannot synchronize the transmission progress.

[0011] To address the aforementioned issues, the technical solution adopted in this invention is a Bluetooth Low Energy-based meeting minutes synchronization method and protocol, comprising five core steps: data encapsulation, intelligent packet segmentation, reliable transmission, breakpoint resumption, and state synchronization, as detailed below:

[0012] I. Data Encapsulation Steps

[0013] The meeting minutes data is compressed and a metadata header containing the meeting ID, total data length, compressed size, CRC32 checksum, and timestamp is added to form encapsulated data.

[0014] Furthermore, the data encapsulation step specifically includes: serializing the transcribed text of the meeting minutes, AI analysis results, and metadata into JSON, and then compressing them using the GZIP algorithm, achieving a compression rate of 50%-60%. The metadata header also includes version information for protocol compatibility management.

[0015] II. Intelligent Subcontracting Steps

[0016] Based on BLEMTU's dynamic calculation of packet size, the encapsulated data is intelligently divided into packets, with each data packet containing a packet sequence number, total number of packets, data payload, and packet-level CRC16 check value.

[0017] Furthermore, the intelligent packet segmentation step is as follows: the default data packet payload is 185 bytes, with 20 bytes reserved for the header space. The total number of packets is the compressed data size divided by 185 bytes and then rounded up. The format of each data packet is as follows: bytes 0-1 are the packet sequence number (big-endian, 2 bytes), bytes 2-3 are the total number of packets (big-endian, 2 bytes), bytes 4-188 are the data payload (185 bytes, padded with zeros if necessary), and bytes 189-190 are the CRC16 checksum (CCITT standard, 2 bytes).

[0018] III. Reliable Transmission Steps

[0019] A sliding window mechanism is used to send data packets one packet at a time via BLEGATTCharacteristic. After receiving the data packet, the receiver replies with ACK or NACK confirmation information, and the sender performs timeout retransmission control based on the confirmation information.

[0020] Furthermore, the sliding window mechanism has a window size of 4 packets, and the sender can continuously send a maximum of 4 packets before waiting for the receiver's ACK confirmation. The timeout for retransmission is 100ms, and the maximum number of retransmissions is 3. If no ACK is received after 3 retransmissions, the packet transmission is marked as failed.

[0021] Furthermore, the transmission process is managed by a state machine, with the state transitions being as follows: IDLE (idle), CONNECTING (connecting), HANDSHAKING (handshaking), TRANSFERRING (transmitting), VERIFYING (verifying), and COMPLETE (complete).

[0022] Furthermore, the BLEGATTCharacteristic includes: meeting minutes synchronization service UUID 0xFFE0, data writing feature UUID 0xFFE1, control command feature UUID 0xFFE2, status notification feature UUID 0xFFE3, and device information query feature UUID 0xFFE4. The control commands include the START command to start transmission, the RESUME command to resume interrupted transmission, the CANCEL command to cancel transmission, and the VERIFY command to verify integrity.

[0023] IV. Steps for resuming interrupted downloads

[0024] When the transmission connection is interrupted, the receiver saves the sequence number of the last received packet as the breakpoint location to non-volatile storage. After the connection is re-established, the receiver sends a breakpoint resume request to the sender. After verifying the validity of the breakpoint, the sender continues to transmit the remaining data packets from the breakpoint location.

[0025] Furthermore, the breakpoint validity verification for the resume transmission includes: verifying whether the meeting ID matches, whether the data version is consistent, and whether the timestamp is within its validity period. After successful verification, the sender continues transmission from the next packet after the breakpoint sequence number.

[0026] V. State Synchronization Steps

[0027] During transmission, the transmission status is pushed in real time through the BLENotify feature, so that the transmission progress can be displayed synchronously on the LCD screen of the hardware device and the mobile APP.

[0028] Furthermore, the real-time push of transmission status via the BLENotify feature specifically means that the status update frequency is once every 5% of the transmission progress or once per second, and the status information includes the current transmission progress percentage, the number of packets transmitted, the total number of packets, and the transmission status.

[0029] Furthermore, the present invention also includes a security encryption step: end-to-end encryption of transmitted data is performed using the AES-128-GCM algorithm, the encryption key is exchanged via out-of-band (OOB) during pairing, and a different session key is generated for each connection.

[0030] The advantages of this invention compared to the prior art are:

[0031] 1. Significantly improved transmission reliability

[0032] This invention constructs a complete reliable transmission protocol through packet-level CRC16 checksum, ACK / NACK confirmation mechanism, and timeout retransmission strategy. The transmission success rate is increased from approximately 85% in standard BLE to over 99.5%, effectively solving the problem of packet loss in BLE packet transmission. The sliding window mechanism ensures reliability while also considering transmission throughput, balancing transmission efficiency and retransmission costs.

[0033] 2. Supports resume download after interruption, improving transmission efficiency.

[0034] This invention achieves breakpoint resumption functionality in BLE transmission by using a mechanism where the receiver saves the breakpoint location and reconnects to resume transmission. For meeting minutes data of 100KB or even several MB, there is no need to start transmission from the beginning after a connection interruption, significantly reducing the amount of data transmitted repeatedly and greatly improving transmission efficiency, making it particularly suitable for scenarios with unstable BLE connections.

[0035] 3. Real-time progress feedback enhances user experience.

[0036] This invention utilizes the BLENotify feature to push transmission status in real time, allowing users to monitor the transmission progress and status at any time, avoiding anxiety and repetitive operations caused by not being aware of the transmission status. The design of simultaneous display on the hardware LCD and the mobile app allows users to check the transmission status independently of their phones, making it more convenient to use.

[0037] 4. End-to-end encryption ensures data security.

[0038] This invention employs the AES-128-GCM algorithm for end-to-end encryption, with keys exchanged via out-of-band (OOB) communication. Each connection uses a different session key, effectively ensuring the secure transmission of business secrets such as meeting minutes and preventing the risk of data leakage.

[0039] 5. Low power consumption optimization, suitable for portable devices

[0040] This invention is designed based on BLE low-power technology. The sliding window mechanism and intelligent timeout retransmission strategy effectively control power consumption while ensuring transmission reliability, making it ideal for battery-powered portable conferencing devices. Transmitting 150KB of data takes only about 20 seconds, achieving efficient transmission while maintaining low power consumption.

[0041] 6. Optimization for meeting minutes scenarios

[0042] This invention designs a specialized packetization strategy and compression scheme for the large text data characteristics of meeting minutes, achieving a GZIP compression rate of 50%-60%, effectively reducing the amount of data transmitted. The metadata header includes information such as the meeting ID and timestamp, facilitating the management and retrieval of meeting minutes and better suiting the practical application scenarios of meeting minutes synchronization. Attached Figure Description

[0043] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0044] Figure 1 This is a diagram of the BLE meeting minutes synchronization system architecture in the Bluetooth Low Energy-based meeting minutes synchronization method and protocol of this invention.

[0045] Figure 2 This is a schematic diagram of the data packet format in the Bluetooth Low Energy-based meeting minutes synchronization method and protocol of the present invention.

[0046] Figure 3 This is a transmission state machine diagram of the Bluetooth Low Energy-based meeting minutes synchronization method and protocol of the present invention.

[0047] Figure 4 This is a timing diagram of the breakpoint resumption transmission in the Bluetooth Low Energy-based meeting minutes synchronization method and protocol of this invention.

[0048] Figure 5 This is a diagram of the GATT service structure in the Bluetooth Low Energy-based meeting minutes synchronization method and protocol of this invention.

[0049] Figure 6 This is an event system architecture diagram of the Bluetooth Low Energy-based meeting minutes synchronization method and protocol of the present invention.

[0050] Figure 7 This is a schematic diagram of the sliding window mechanism in the Bluetooth Low Energy-based meeting minutes synchronization method and protocol of the present invention.

[0051] Figure 8 This is a flowchart illustrating the secure encrypted transmission process in the Bluetooth Low Energy-based meeting minutes synchronization method and protocol of this invention. Detailed Implementation

[0052] 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.

[0053] The following describes, with reference to the accompanying drawings, a method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy according to an embodiment of the present invention.

[0054] Combined with appendix Figure 1-8This invention relates to a Bluetooth Low Energy (BLE) meeting minutes synchronization method and protocol. Its overall system architecture comprises six core components: a data encapsulation module, an intelligent packet segmentation module, a reliable transmission module, a breakpoint resumption module, a status synchronization module, and a security encryption module. These modules work collaboratively to achieve reliable, efficient, and secure transmission of meeting minutes data in a BLE environment. This system is built upon the standard BLEGATT protocol stack, requiring no modification to the underlying Bluetooth hardware structure, and improves transmission performance through application-layer protocol optimization.

[0055] The data encapsulation module is responsible for standardizing and encapsulating the raw meeting minutes data. Meeting minutes data includes various types of content such as transcribed text, AI analysis results, and metadata. The data encapsulation module first performs JSON serialization on these data types to form structured data in a unified format. After serialization, the data encapsulation module uses the GZIP algorithm to compress the structured data, achieving high compression efficiency for text-based meeting minutes data. After compression, the data encapsulation module adds a metadata header to the front end of the compressed data. The metadata header includes the meeting ID, total data length, compressed size, CRC32 checksum, timestamp, and version information. The meeting ID uniquely identifies the minutes data of a single meeting; the total data length and compressed size are used for data verification and reassembly at the receiving end; the CRC32 checksum is used for overall data integrity verification; the timestamp is used to verify the validity of resuming interrupted transmissions; and the version information is used for protocol compatibility management.

[0056] The intelligent packet segmentation module is responsible for dynamically calculating packet size based on BLEMTU and completing data packet segmentation. Due to the MTU limitation of the BLE protocol, large data volumes must be split into multiple data packets for transmission. The intelligent packet segmentation module first obtains the MTU value of the current BLE connection, and dynamically calculates the effective payload length of each data packet based on the MTU value, maximizing the data volume of a single packet while ensuring that it does not exceed the MTU limit. Each data packet contains four parts: packet sequence number, total number of packets, data payload, and packet-level CRC16 checksum. The packet sequence number is used to identify the sequential position of the data packets, facilitating the receiving end to reassemble the data in order. The total number of packets informs the receiving end of the total number of data packets transmitted, helping the receiving end to judge the transmission progress. The data payload carries the actual encapsulated data content. The packet-level CRC16 checksum is calculated using the CCITT standard and is used for integrity verification of single-packet data, ensuring that each data packet is not corrupted during transmission.

[0057] The reliable transmission module is responsible for implementing a reliable data packet sending and acknowledgment mechanism. It employs a sliding window mechanism to control the sending pace of data packets. Data packets within a sending window can be sent continuously, and when the window is full, it waits for acknowledgment from the receiver. This sliding window mechanism improves transmission throughput while ensuring transmission reliability, balancing transmission efficiency and retransmission costs. Upon receiving each data packet, the receiver first performs a CRC16 check. If the check passes, it replies with an ACK confirmation; otherwise, it replies with a NACK negative confirmation. Upon receiving an ACK confirmation, the sender removes the corresponding data packet from the sending window and continues sending subsequent data packets. The sender has a timeout retransmission mechanism. If an ACK confirmation for the corresponding data packet is not received within a specified time, a retransmission is triggered. A maximum number of retransmissions is set; exceeding this limit indicates a transmission failure. The reliable transmission module also includes a state machine management mechanism. The transmission process is divided into multiple state stages, each flowing according to preset rules to ensure the orderly and controllable transmission process.

[0058] The breakpoint resumption module is responsible for resuming transmission after a connection interruption. This module sets up a non-volatile storage area on the receiving end to store breakpoint information. During transmission, the receiving end updates the sequence number of the last received packet in real time. When the connection is unexpectedly interrupted, the receiving end writes the sequence number of the last received packet, the meeting ID, and the timestamp into the non-volatile storage area as a breakpoint record. After re-establishing the BLE connection, the receiving end reads the breakpoint record and sends a breakpoint resumption request to the sender, carrying the breakpoint location information. Upon receiving the resumption request, the sender verifies the breakpoint validity, checking if the meeting ID matches, the data version is consistent, and the timestamp is valid. If verification is successful, the sender continues transmitting the remaining data packets starting from the packet after the breakpoint sequence number, without having to start transmission from the beginning. This breakpoint resumption mechanism effectively reduces the amount of duplicate data transmission caused by connection interruptions, significantly improving transmission efficiency in unstable connection environments.

[0059] The status synchronization module is responsible for real-time display of transmission status. It utilizes the BLENotify feature to push transmission status information, including the current transmission progress percentage, number of packets transmitted, total number of packets, and transmission status. Status updates employ a dual-trigger mechanism: pushing updates at fixed time intervals and based on progress percentage milestones, ensuring users are promptly informed of transmission status changes. The module supports both a hardware device LCD screen and a mobile app, with progress information updated synchronously on both devices. The hardware LCD display allows users to view the transmission status independently of their phones, while the mobile app provides richer interactive features. This dual-terminal synchronous display mechanism enhances user convenience in various usage scenarios.

[0060] The security encryption module is responsible for ensuring the security of transmitted data. It employs the AES-128-GCM algorithm for end-to-end encryption of transmitted data, simultaneously protecting data confidentiality and integrity. Encryption keys are exchanged via out-of-band (OOB) communication during the pairing process, avoiding the risk of plaintext key transmission over the BLE link. A unique session key is generated for each connection establishment, with different keys used for different connections, reducing the impact of key leakage. The security encryption module performs encryption before data transmission and decryption after data reception; the encryption and decryption processes are transparent to upper-layer applications.

[0061] The BLEGATT service definition of this invention includes a main service and multiple feature values. The main service is a meeting minutes synchronization service, used to carry all functions related to meeting minutes synchronization. The data writing feature is used to transmit the actual data packet content, with the sender writing data to the receiver. The control command feature is used to transmit control commands, supporting bidirectional communication, and is used to transmit control commands such as start, resume, cancel, and verification. The status notification feature is used to push transmission status information, using a Notify method where the server actively pushes information to the client. The device information query feature is used to query basic device information, supporting client-side reading. The above GATT service and feature value definitions are implemented within the standard BLE protocol framework, compatible with mainstream Bluetooth chips and operating systems.

[0062] The working principle of this application is as follows: This invention is based on a Bluetooth Low Energy (BLE) meeting minutes synchronization method and protocol. Its working principle lies in optimizing the application layer protocol to build a reliable transmission system for meeting minutes scenarios based on the standard BLEGATT protocol. The data encapsulation module reduces the amount of transmitted data and provides a basis for integrity verification through compression and metadata header processing. The intelligent packet segmentation module dynamically adjusts the packet size according to the MTU, maximizing transmission efficiency within protocol limitations, while achieving traceability and integrity verification of single packets through packet sequence numbers and packet-level verification. The reliable transmission module achieves high-success-rate data transmission under low power consumption conditions through a sliding window mechanism and ACK / NACK confirmation mechanism, and the timeout retransmission mechanism further ensures transmission reliability in unstable connection environments. The breakpoint resumption module saves the breakpoint position through non-volatile storage and, combined with the validity verification mechanism, enables rapid resumption of transmission after connection interruption, avoiding the time and power waste caused by repeated transmissions. The status synchronization module utilizes the BLENotify feature to achieve real-time push of status information, and the dual-terminal synchronous display mechanism meets the user needs of different usage scenarios. The security encryption module ensures the secure transmission of sensitive data such as meeting minutes through end-to-end encryption and an OOB key exchange mechanism. These modules work together to address various challenges related to reliability, efficiency, user experience, and security when transmitting large volumes of meeting minutes using BLE, achieving low-power, highly reliable, and highly efficient synchronous transmission of meeting minutes.

[0063] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art, inspired by this description, design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy, characterized in that: Includes the following steps: The meeting minutes data is compressed and a metadata header containing the meeting ID, total data length, compressed size, CRC32 checksum, and timestamp is added to form encapsulated data. Based on BLEMTU's dynamic calculation of packet size, the encapsulated data is intelligently divided into packets, each data packet containing a packet sequence number, total number of packets, data payload, and packet-level CRC16 check value; A sliding window mechanism is used to send data packets one packet at a time via BLEGATTCharacteristic. After receiving the data packet, the receiver replies with ACK or NACK confirmation information, and the sender performs timeout retransmission control based on the confirmation information. When the transmission connection is interrupted, the receiver saves the sequence number of the last received packet as the breakpoint location to non-volatile storage. After the connection is re-established, the receiver sends a breakpoint resume request to the sender. After verifying the validity of the breakpoint, the sender continues to transmit the remaining data packets from the breakpoint location. During transmission, the transmission status is pushed in real time through the BLENotify feature, so that the transmission progress can be displayed synchronously on the LCD screen of the hardware device and the mobile APP.

2. The method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy as described in claim 1, characterized in that: The specific steps of compressing the meeting minutes data include: serializing the transcribed text of the meeting minutes, AI analysis results, and metadata into JSON, and then compressing them using the GZIP algorithm, with a compression rate of 50%-60%.

3. The method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy as described in claim 1, characterized in that: The specific method for dynamically calculating the packet size based on BLEMTU is as follows: the default data packet payload is 185 bytes, with 20 bytes of header space reserved. The total number of packets is the compressed data size divided by 185 bytes and then rounded up. The format of each data packet is as follows: bytes 0-1 are the packet sequence number, bytes 2-3 are the total number of packets, bytes 4-188 are the data payload, and bytes 189-190 are the CRC16 check value.

4. The method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy as described in claim 1, characterized in that: The sliding window mechanism has a window size of 4 packets. The sender can send a maximum of 4 packets of data consecutively and then wait for the receiver's ACK confirmation. The timeout for retransmission is 100ms, and the maximum number of retransmissions is 3. If no ACK is received after more than 3 retransmissions, the packet transmission is marked as failed.

5. The method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy according to claim 1, characterized in that: The breakpoint validity verification for the breakpoint resume transmission includes: verifying whether the meeting ID matches, whether the data version is consistent, and whether the timestamp is within the validity period; after the verification is successful, the sender continues transmission from the next packet after the breakpoint sequence number.

6. The method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy according to claim 1, characterized in that: The real-time push of transmission status via the BLENotify feature specifically means that the status update frequency is once every 5% of the transmission progress or once per second. The status information includes the current transmission progress percentage, the number of packets transmitted, the total number of packets, and the transmission status.

7. The method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy according to claim 1, characterized in that: It also includes security encryption steps: the AES-128-GCM algorithm is used to encrypt the transmitted data end-to-end, the encryption key is exchanged in an out-of-band manner during pairing, and a different session key is generated for each connection.

8. The method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy according to claim 1, characterized in that: The BLEGATTCharacteristic includes: meeting minutes synchronization service UUID 0xFFE0, data writing feature UUID 0xFFE1, control command feature UUID 0xFFE2, status notification feature UUID 0xFFE3, and device information query feature UUID 0xFFE4; the control commands include START to start transmission, RESUME to resume interrupted transmission, CANCEL to cancel transmission, and VERIFY to verify integrity.

9. The method and protocol for synchronizing meeting minutes based on Bluetooth Low Energy according to claim 1, characterized in that: The transmission process is managed by a state machine, and the state transitions are as follows: IDLE (idle), CONNECTING (connecting), HANDSHAKING (handshaking), TRANSFERRING (transmitting), VERIFYING (verifying), and COMPLETE (complete).

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