Time-sequenced dynamic key flexible pairing wireless audio transmission system

Abstract

The application relates to the technical field of wireless microphones, and discloses a time sequence dynamic key flexible pairing wireless audio transmission system which is used for realizing the pairing of preset transmitters and receivers; the transmitter comprises a first time sequence key module, a first communication engine and a first key management unit, the receiver comprises a second time sequence key module, a second communication engine and a second key management unit; the first time sequence key module and the second time sequence key module generate a first dynamic key and a second dynamic key based on corresponding RTC clocks of the transmitter and the receiver respectively; the first communication engine and the second communication engine both support a pairing mode; the pairing mode is used for completing the initial time synchronization and key negotiation of the transmitter and the receiver; the first key management unit and the second key management unit store the first dynamic key and the second dynamic key respectively, and both store a time offset calibration value and a dynamic key validity period which are used for compensating for the drift of the corresponding RTC clocks of the transmitter and the receiver.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless microphones, in particular to a timing dynamic key flexible pairing wireless audio transmission system. BACKGROUND

[0002] In the field of wireless audio transmission, 2.4G frequency band is widely used in earphones, microphones and other devices due to its low cost and strong compatibility, but the traditional scheme generally faces two technical bottlenecks: communication interruption caused by different timing of dynamic key and insufficient flexibility of multi-device pairing.

[0003] In the prior art, the pairing scheme based on dynamic key usually tolerates the RTC clock drift of the transmitter and the receiver with a fixed time window (such as ± 30 seconds), but due to the individual differences of the devices (such as crystal oscillator aging and environmental temperature change), the RTC error will accumulate over time (typical error ± 10ppm or more), resulting in frequent timing deviation when switching dynamic key, and ultimately causing packet loss or even disconnection. To solve this problem, some schemes rely on the auxiliary time synchronization of the Bluetooth module or increase a special clock calibration chip, which can improve the synchronization accuracy, but significantly increases the hardware cost and system complexity, which is contrary to the design goal of low-cost wireless audio devices.

[0004] In addition, the traditional pairing process usually adopts one-way key negotiation (such as only the transmitter initiates pairing), and the receiver responds passively, and lacks real-time clock calibration mechanism, which cannot dynamically compensate the RTC drift, resulting in a decrease in the pairing success rate of old devices or devices working for a long time with the use time (the pairing failure rate is more than 20% after 1 year of actual measurement). For professional audio scenes that need to frequently switch pairing objects (such as multi-device cooperation on the stage), this “static pairing” mode cannot meet the flexible adaptation requirements, which has become a common technical pain point in the industry.

[0005] Therefore, there is an urgent need for a system to solve at least one of the above problems. SUMMARY

[0006] The present application provides a timing dynamic key flexible pairing wireless audio transmission system, which aims to realize flexible and secure dynamic pairing without increasing hardware cost and fully utilizing existing 2.4G radio frequency and MCU resources.

[0007] In a first aspect, the present application provides a timing dynamic key flexible pairing wireless audio transmission system for realizing pairing of a preset transmitter and receiver.

[0008] The transmitter comprises a first time key module, a first communication engine and a first key management unit, the receiver comprises a second time key module, a second communication engine and a second key management unit; the first time key module and the second time key module generate a first dynamic key and a second dynamic key respectively based on the corresponding RTC clock of the transmitter and the receiver; the first communication engine and the second communication engine both support a pairing mode; the pairing mode is used to complete the initial time synchronization and key negotiation of the transmitter and the receiver; the first key management unit and the second key management unit respectively store the first dynamic key and the second dynamic key, and both store a time offset calibration value and a dynamic key validity period for compensating the drift of the corresponding RTC clock of the transmitter and the receiver.

[0009] Wherein, after receiving the pairing request, the transmitter and the receiver respectively acquire a first RTC timestamp and a second RTC timestamp of the corresponding RTC clock, and the first time key module and the second time key module respectively calculate the first dynamic key and the second dynamic key according to the corresponding first RTC timestamp and second RTC timestamp; in the pairing mode, the receiver broadcasts a pairing request packet corresponding to the first dynamic key, the transmitter listens to the pairing request packet and completes the key negotiation according to the first dynamic key and the second dynamic key, the time offset calibration value and the dynamic key validity period, and after the key negotiation is passed, the transmitter generates a pairing response packet and broadcasts it to the receiver, completing the pairing of the transmitter and the receiver.

[0010] In some embodiments, the first key management unit and the second key management unit respectively store a preset root key; after the transmitter generates a pairing response packet and broadcasts it to the receiver after the key negotiation is passed, the first key management unit acquires and stores the corresponding second dynamic key and receiver identification information of the receiver, the second key management unit acquires the corresponding first dynamic key and transmitter identification information of the transmitter, completing the pairing of the transmitter and the receiver; and completes the transmission of the preset audio signal according to the root key.

[0011] In some embodiments, the first communication engine and the second communication engine also support a transmission mode, which is used to perform secure transmission of audio data based on a preset encryption algorithm in the transmission mode.

[0012] In some embodiments, the transmission mode is used for radio frequency transmission in a preset frequency band, and the frequency band range corresponding to the preset frequency band is 2400-2483.5 MHz.

[0013] In some embodiments, the receiver is connected with a preset upper terminal; the second dynamic key is generated for the upper terminal and written into the key injection interface corresponding to the second time key module.

[0014] In some embodiments, the second dynamic key is a time-based one-time dynamic key, and the generation of the second dynamic key is based on a HMAC-SHA1 algorithm.

[0015] In some embodiments, the transmitter detects a type of the connected device through a preset compatible mode switching module, and switches to a fixed key protocol matched with an old receiver for communication when determining that the device type is the old receiver.

[0016] In some embodiments, the first and second timing key modules write the first and second key information to the first and second communication engines respectively based on a preset extended instruction set, so as to complete the generation of the pairing request packet and the key negotiation; wherein the extended instruction set includes instruction information for writing keys.

[0017] In some embodiments, the first and second dynamic keys are generated through a preset algorithm based on time synchronization, and the preset algorithm includes a time-based one-time password algorithm.

[0018] In some embodiments, the transmitter and the receiver respectively include first and second user interaction interfaces, and the pairing request is generated when the first and second user interaction interfaces are triggered.

[0019] The application belongs to the technical field of wireless microphones, and particularly relates to a wireless audio transmission system based on a 2.4G frequency band. Unlike existing solutions, the application does not require additional hardware modules (such as a Bluetooth chip), but only realizes low-cost, high-precision time synchronization and key management through software algorithm optimization and system architecture innovation, fundamentally solves the communication interruption problem caused by dynamic key switching, and significantly improves the pairing flexibility and long-term reliability of wireless audio equipment. Through bidirectional timestamp interaction to calculate the time offset calibration value during pairing, the RTC clock drift of the transmitter and the receiver is compensated in real time, the dynamic key generation time is strictly aligned, and the packet loss and disconnection problems caused by asynchronous key switching are completely solved. The pairing mode adopts bidirectional communication negotiation (the receiver broadcasts a pairing request packet, and the transmitter actively responds), which is different from the traditional one-way pairing process, supports multiple receivers to initiate pairing at the same time, and can dynamically adjust the key generation parameters according to the real-time RTC state of the device, so that a single transmitter can be flexibly adapted to 10+ different models of receivers (the traditional scheme only supports 3-5 fixed models), significantly improving the pairing efficiency in a multi-device scenario. Not dependent on the Bluetooth module or the special calibration chip, only through the software-defined time key module + communication engine dual-mode design, the existing 2.4G communication hardware resources are reused, high-precision time synchronization is realized within the range of MCU computing power, and the low-cost mass production demand of consumer-grade devices is met.

[0020] The dynamic key validity period (default: ±30 seconds) stored by the key management unit provides an elastic tolerance window for the time deviation, and in combination with the real-time calibration value updating mechanism, the RTC drift caused by factors such as temperature change (-20℃~60℃) and device aging can be automatically adapted, so that the pairing success rate of the device in extreme environments is improved, which is significantly better than the traditional fixed window scheme.

[0021] In summary, through the system architecture innovation of “bidirectional timestamp calibration + dynamic key negotiation”, the application breaks through the time synchronization bottleneck of traditional 2.4G wireless audio equipment without increasing hardware costs, realizes the technical effects of “high-precision synchronization, low-cost adaptation, and strong environmental adaptation”, and the core creativity lies in deeply integrating the RTC clock management, key generation algorithm, and communication protocol to form a self-calibration dynamic pairing mechanism, which provides a new technical path for the large-scale application of wireless audio equipment.

[0022] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the application. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without creative work based on these drawings are within the scope of the present application.

[0024] Figure 1 is a structural schematic block diagram of a first timing dynamic key flexible pairing wireless audio transmission system provided by an embodiment of the present application;

[0025] Figure 2 is a structural schematic block diagram of a second timing dynamic key flexible pairing wireless audio transmission system provided by an embodiment of the present application;

[0026] Figure 3 is a schematic diagram of an original scheme of a timing dynamic key flexible pairing wireless audio transmission system provided by an embodiment of the present application;

[0027] Figure 4 is a first improved scheme of a timing dynamic key flexible pairing wireless audio transmission system provided by an embodiment of the present application;

[0028] Figure 5 is a second improved scheme of a timing dynamic key flexible pairing wireless audio transmission system provided by an embodiment of the present application.

[0029] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of the present application.

[0031] The flowcharts shown in the drawings are only exemplary, and do not necessarily include all the contents and operations / steps, and do not necessarily be executed in the described order. For example, some operations / steps can be decomposed, combined or partially combined, so that the actual execution order can be changed according to the actual situation.

[0032] It should be understood that, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, the terms "first", "second", etc. are used to distinguish the same items or similar items with basically the same function and role. Those skilled in the art can understand that the terms "first", "second", etc. do not limit the quantity and execution order, and the terms "first", "second", etc. also do not necessarily mean different.

[0033] It should be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and do not intend to limit the present application. As used in the present application specification and the appended claims, unless otherwise clear from the context, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0034] It should also be understood that the term "and / or" used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0035] Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments and features in the embodiments can be combined with each other without conflict.

[0036] In the field of wireless audio transmission, the 2.4G frequency band is widely used in earphones, microphones and other devices due to its low cost and strong compatibility, but traditional schemes generally face two technical bottlenecks: communication interruption caused by dynamic key timing asynchronization and insufficient flexibility of multi-device pairing.

[0037] In the prior art, the pairing scheme based on dynamic keys usually uses a fixed time window (such as ±30 seconds) to tolerate the RTC clock drift of the transmitter and the receiver, but due to individual differences of devices (such as crystal oscillator aging, environmental temperature changes), the RTC error will accumulate over time (typical error ±10ppm or more), resulting in frequent timing deviation when switching dynamic keys, ultimately causing packet loss or even disconnection. To solve this problem, some schemes rely on the Bluetooth module to assist time synchronization, or increase a dedicated clock calibration chip, although it can improve synchronization accuracy, but significantly increases hardware cost and system complexity, which is contrary to the design goal of low-cost wireless audio devices.

[0038] In addition, the traditional pairing process mostly uses one-way key negotiation (such as only the transmitter initiates pairing), and the receiver passively responds, and lacks a real-time clock calibration mechanism, which cannot dynamically compensate for RTC drift, resulting in a decrease in the pairing success rate of old devices or devices that have been working for a long time over time (measured pairing failure rate of more than 20% after 1 year). For professional audio scenes that require frequent switching of pairing objects (such as multi-device collaboration on stage), this "static pairing" mode is difficult to meet the flexible adaptation requirements, and has become a common technical pain point in the industry.

[0039] The present application is directed to the above problems, and proposes a flexible pairing system based on time sequence dynamic key, which calculates time offset calibration value through bidirectional timestamp interaction of the transmitter and the receiver, compensates RTC clock drift in real time, and embeds dynamic key negotiation mechanism in the pairing mode to ensure that both sides maintain time sequence consistency when the dynamic key is switched. Unlike existing solutions, the present application does not require additional hardware modules (such as Bluetooth chips), but only optimizes software algorithms and innovates system architecture to realize low-cost, high-precision time synchronization and key management, fundamentally solving the communication interruption problem caused by dynamic key switching, and significantly improving the pairing flexibility and long-term reliability of wireless audio devices.

[0040] Please refer to Figure 1 The present application provides a time sequence dynamic key flexible pairing wireless audio transmission system for realizing pairing of a preset transmitter 10 and a receiver 20; the transmitter 10 comprises a first time sequence key module 11, a first communication engine 12 and a first key management unit 13, and the receiver 20 comprises a second time sequence key module 21, a second communication engine 22 and a second key management unit 23; the first time sequence key module 11 and the second time sequence key module 21 generate a first dynamic key and a second dynamic key based on corresponding RTC clocks of the transmitter 10 and the receiver 20 respectively; the first communication engine 12 and the second communication engine 22 both support pairing mode; the pairing mode is used to complete initial time synchronization and key negotiation of the transmitter 10 and the receiver 20; the first key management unit 13 and the second key management unit 23 respectively store the first dynamic key and the second dynamic key, and both store a time offset calibration value for compensating RTC clock drift of the transmitter 10 and the receiver 20 and a dynamic key validity period; wherein, after receiving a pairing request, the transmitter 10 and the receiver 20 acquire a first RTC timestamp and a second RTC timestamp of corresponding RTC clocks respectively, and the first time sequence key module 11 and the second time sequence key module 21 calculate the first dynamic key and the second dynamic key respectively according to the corresponding first RTC timestamp and the second RTC timestamp; in the pairing mode, the receiver 20 broadcasts a pairing request packet corresponding to the first dynamic key, the transmitter 10 listens to the pairing request packet and completes key negotiation according to the first dynamic key and the second dynamic key, the time offset calibration value and the dynamic key validity period, the transmitter 10 generates a pairing response packet and broadcasts it to the receiver 20 after the key negotiation is passed, and the pairing of the transmitter 10 and the receiver 20 is completed.

[0041] Specifically, the present application provides a time sequence dynamic key flexible pairing wireless audio transmission system, which realizes high-precision pairing and secure communication without relying on Bluetooth modules through bidirectional time synchronization and dynamic key negotiation mechanism of the transmitter 10 and the receiver 20.

[0042] The first and second time sequence key modules 11 and 21 (transmitter 10 / receiver 20 end) are built-in high-precision RTC clocks (error ≤ ± 10 ppm), based on TOTP (time-based one-time password) or similar time sequence algorithm, and generate dynamic keys (such as updated every 30 seconds) according to the local RTC timestamp. The dynamic key is strongly bound with the timestamp, ensuring that the transmitter 10 and the receiver 20 generate the same key within the synchronized time window, avoiding communication failure caused by inconsistent keys from the source.

[0043] The first and second communication engines 12 and 22 (transmitter 10 / receiver 20 end) support dual-mode operation: pairing mode: through clear transmission control instructions (such as timestamp, key negotiation request), initial time synchronization and key negotiation are completed, laying the foundation for subsequent encrypted communication; transmission mode: using AES-128 encryption algorithm for secure transmission of audio data, ensuring that the link layer data is eavesdropping-proof.

[0044] The first and second key management units 13 and 23 (transmitter 10 / receiver 20 end) store three core parameters: dynamic key: real-time key generated by the time sequence key module, used for encrypting / decrypting audio data; time offset calibration value: calculated through bidirectional timestamp interaction during pairing, compensating for individual differences (such as crystal oscillator drift) of the RTC clocks of the transmitter 10 and the receiver 20; dynamic key validity period: defines the allowed time sequence deviation tolerance window (default ± 30 seconds), ensuring that both parties can still generate valid keys when the RTC slightly drifts.

[0045] Unlike traditional one-way pairing (only the transmitter 10 initiates the request), the system adopts a bidirectional interaction mode of active broadcasting by the receiver 20 and intelligent response by the transmitter 10: time synchronization: during pairing, both parties exchange RTC timestamps, calculate the initial time offset (such as the difference ΔT between the transmitter 10 timestamp T1 and the receiver 20 timestamp T2), and store ΔT as the calibration value, which is automatically compensated when generating dynamic keys (key generation time = local time - ΔT) later; key negotiation: based on the transmitter 10 dynamic key, the receiver 20 dynamic key, the calibration value, and the validity period, the transmitter 10 verifies the consistency of the keys of both parties within the time window, ensuring that only time-synchronized devices complete pairing and eliminating misconnections of cross-time sequence devices.

[0046] In some embodiments, the transmitter 10 / receiver 20 each integrates a low-cost MCU (such as STM32F103), a 2.4G wireless transceiver chip (such as nRF24L01), and a high-precision RTC module (externally connected with a 32.768 kHz crystal oscillator, with an error of ±10 ppm); the dynamic key algorithm uses the TOTP algorithm (HMAC-SHA1), and the key generation formula is: dynamic key = TOTP (key seed, current RTC timestamp, time step 30 seconds), wherein the key seed is generated by negotiation during pairing and stored in the key management unit; the time offset calculation is performed through the bidirectional timestamp interaction formula ΔT = (T2send - T1receive + T1send - T2receive) / 2, so as to eliminate the signal transmission delay and improve the calibration accuracy.

[0047] By pressing the physical pairing button of the transmitter 10 / receiver 20 for 3 seconds, the LED blue light flashes, the device enters the pairing mode, and the communication engine switches to the broadcast / listen state. The second time sequence key module 21 of the receiver 20 acquires the current RTC timestamp T2 and generates the second dynamic key K2; the second communication engine 22 encapsulates the pairing request packet (containing the device ID, T2, and K2 hash value) and broadcasts it to the 2.4G frequency band at an interval of 200 ms for 10 seconds. After the first communication engine 12 of the transmitter 10 receives the request packet, it extracts T2 and K2 hash value, acquires the RTC timestamp T1 of itself, generates the first dynamic key K1, calculates the initial time offset ΔT = T1 - T2, verifies whether K1 and K2 correspond to the same time sequence key within the ΔT ± dynamic key validity period (±30 seconds) window (i.e. K1 = K2 (local time - ΔT)), and if the verification is passed, the next step is entered; if it fails (such as a large time sequence deviation), ΔT is recalculated (with a maximum of 3 retries to avoid invalid power consumption) after waiting for the next request packet. The first communication engine 12 generates a pairing response packet (containing T1, ΔT, key seed, and validity period parameter) and broadcasts it to the receiver 20; after the receiver 20 receives it, it stores ΔT as the time offset calibration value, and in the subsequent generation of the dynamic key, automatically uses the local time - ΔT as the input timestamp to ensure time sequence alignment with the transmitter 10; the dynamic key validity period parameters of the key management units of both parties are updated synchronously (such as the user can customize it to ±15 seconds to ±60 seconds through the APP). The LED indicator light turns to blue constant light, the communication engine switches to the AES-128 encryption mode, and the audio data is encrypted and transmitted based on the synchronized dynamic key; during the transmission process, 1 calibration packet with timestamp (containing the current RTC) is inserted every 10 audio data packets, the ΔT change is monitored in real time, and if the offset exceeds 80% of the validity period (such as ±24 seconds), the calibration value is automatically updated to avoid accumulated errors leading to disconnection.

[0048] Through the bidirectional timestamp calibration mechanism, the timing deviation of the transmitter 10 and the receiver 20 is converted from the ''fixed window tolerance'' of the traditional scheme to ''real-time dynamic compensation'', the actual continuous working 24 hours disconnection times are reduced from 15 times to 0 times, and the packet loss problem during key switching is completely solved (the bit error rate is reduced from 10^-3 level to 10^-6 level). The receiver 20 can actively initiate a pairing request, and a single transmitter 10 can simultaneously respond to the pairing broadcast of 10+ receivers 20 (the traditional scheme only supports 3-5 one-way pairing), which is especially suitable for multi-device rapid networking scenes such as stage performances and conference systems, and the pairing efficiency is improved by 300% (from 5 minutes / group of manual one-by-one pairing to 10 seconds / group of automatic negotiation). Without relying on Bluetooth modules or special clock chips, high-precision synchronization is achieved only through existing 2.4G hardware and algorithm optimization, compatible with mainstream MCU platforms (such as ESP32 and STM32), suitable for mass production of consumer-grade earphones and microphones.

[0049] The dynamic calibration value updating mechanism of the key management unit can automatically adapt to temperature changes (RTC drift compensation efficiency is improved when the temperature is-20 DEG C to 60 DEG C), device aging and other factors, so that the pairing success rate of 3-year-old devices is improved, and the after-sales maintenance cost is significantly reduced.

[0050] TOTP algorithm combined with AES-128 encryption, key update period and time window are dynamically adjustable (minimum 15 seconds), key cracking difficulty is improved by more than 100 times compared with the traditional fixed key scheme, meeting the needs of medical monitoring, radio and television live broadcast and other sensitive data security scenes. In the pairing mode, the negotiation time is reduced, the encryption delay in the transmission mode is reduced, the overall delay is better than the standard of Bluetooth 5.0, and can support instrument monitoring, real-time director and other delay demanding applications.

[0051] The application builds a self-calibration timing synchronization system in the 2.4G wireless transmission architecture through the closed-loop mechanism of ''time stamp bidirectional interaction-dynamic calibration value generation-key negotiation solidification'', converts ''passive tolerance of timing deviation'' in the traditional scheme to ''active compensation of timing difference'', and breaks through the core bottleneck of dynamic key pairing from the system level, which sets a new technical standard for the reliability and flexibility of low-cost wireless audio devices.

[0052] In some embodiments, the first key management unit 13 and the second key management unit 23 respectively store a preset root key; after the transmitter 10 generates a pairing response packet and broadcasts it to the receiver 20 after the key negotiation is passed, the first key management unit 13 acquires and stores the second dynamic key corresponding to the receiver 20 and the receiver 20 identification information, the second key management unit 23 acquires the first dynamic key corresponding to the transmitter 10 and the transmitter 10 identification information, and the pairing of the transmitter 10 and the receiver 20 is completed; and the preset audio signal transmission is completed according to the root key.

[0053] By introducing a root key system on the basis of key negotiation, the mutual authentication dynamic key and identification information of the storage device are stored after pairing is completed, and the root key is used to realize secure transmission of the audio signal. The transmitter 10 / receiver 20 pre-stores the root key (the master key burned when the device is manufactured); after successful pairing, the dynamic key and device ID (such as the MAC address) of the opposite party are stored bidirectionally; during audio transmission, the session key is derived through the root key, forming a double-layer security system of “root key + dynamic key”.

[0054] The root key is pre-configured by writing the same root key (such as a 128-bit AES root key) into the transmitter 10 and the receiver 20 through a secure burning tool during the production stage, and is stored in the secure storage area (tamper-proof Flash) of the key management unit; the root key is only used for identity authentication in the key negotiation stage and does not directly participate in data encryption.

[0055] The pairing response packet generated by the transmitter 10 contains: its own dynamic key K1 (encrypted by the root key); the identification information of the transmitter 10 (such as a 16-bit device ID); and the root key check code (used by the receiver 20 to verify the identity legitimacy).

[0056] Key and identification storage: after receiving the response packet, the receiver 20 decrypts K1 using the local root key, stores it to the second key management unit 23, and records the transmitter 10 ID; the transmitter 10 synchronously stores the K2 and ID of the receiver 20, forming a device pairing list (supporting storage of 5-10 groups of pairing information).

[0057] Audio transmission encryption: when transmitting the audio, the root key is used as a seed to generate a session key (such as an AES-128 session key) in combination with the current dynamic key, and the PCM audio data is block encrypted.

[0058] The root key prevents malicious devices from forging pairing responses, and the dynamic key avoids the risk of key leakage, with a 50-fold increase in cracking difficulty compared to a single key solution; device binding uniqueness: by storing the device ID, it prevents non-paired devices from pretending to access (such as the transmitter 10 only responding to requests from the receiver 20 in the list), which is suitable for professional audio scenarios with high security requirements; the root key is fixed and does not change, and the dynamic key is updated periodically, reducing the power consumption of frequently generating high-strength keys (key derivation time < 50 μs).

[0059] In some embodiments, the first communication engine 12 and the second communication engine 22 also support a transmission mode for securely transmitting audio data based on a preset encryption algorithm in the transmission mode.

[0060] The communication engine supports dual-mode switching, enters the transmission mode (encrypted transmission) after the pairing mode (clear negotiation), and guarantees the security of the audio data based on a preset encryption algorithm (such as AES-128).

[0061] Mode switching logic: Pairing mode: Communication engine works in unencrypted control channel (channel 0x66), transmits control instructions (timestamp, key negotiation package), baud rate set to 250kbps (balance stability and power consumption); transmission mode: After pairing is completed, switch to encrypted channel (channel 0xAA), enable AES-128 encryption module, baud rate is increased to 2Mbps (satisfy 44.1kHz audio transmission bandwidth requirements).

[0062] Encryption process implementation: Transmitter 10 divides audio PCM data into 128-bit data blocks, uses current dynamic key for AES-ECB encryption, and adds 16-bit CRC check code; receiver 20 receives encrypted data, decrypts it through a local dynamic key, and restores the PCM signal after verifying that the CRC is correct.

[0063] Pairing stage plaintext transmission ensures negotiation speed (<200ms), and encrypted transmission in transmission stage prevents audio eavesdropping, balancing security and real-time performance; supports international standard encryption standards such as AES-128, meets CE, FCC, and other certification requirements, and reduces product compliance costs; transmission mode uses frequency hopping technology (combined with 2.4G channel division), combined with encryption processing, to reduce the bit error rate of signals in complex electromagnetic environments.

[0064] In some embodiments, the transmission mode is used for radio frequency transmission in a preset frequency band, and the frequency range corresponding to the preset frequency band is 2400-2483.5MHz.

[0065] The transmission mode explicitly uses the 2.4G ISM frequency band (2400-2483.5MHz), supports globally common license-free radio frequency transmission, and is compatible with mainstream 2.4G wireless chips.

[0066] Frequency band division and channel configuration divide 10 data transmission channels (2402MHz-2480MHz, interval 8MHz), support automatic frequency hopping (AFH) to avoid interference; pairing mode uses channel 2402MHz (public negotiation channel) fixedly, and transmission mode dynamically switches to the optimal channel according to signal strength (scans channel quality every 5 seconds).

[0067] Radio frequency parameter configuration can be transmit power: 0dBm (indoor scene) ~ 10dBm (outdoor extension), supporting software adjustment; receive sensitivity: -95dBm (250kbps) ~ -85dBm (2Mbps), adapting to different transmission distance requirements. Using the 2.4G general frequency band, no additional frequency band license is required, directly entering the mainstream markets in Europe, the United States, Japan, and South Korea; combined with dynamic frequency hopping and frequency band division, effectively avoiding the same frequency interference of Wi-Fi (2.4G), Bluetooth, and other devices, and improving transmission stability in complex environments.

[0068] AsFigure 2 As shown, in some embodiments, the receiver 20 is connected with a preset upper terminal 30; the second dynamic key is generated for the upper terminal 30 and written to the corresponding key injection interface of the second time sequence key module 21.

[0069] The receiver 20 supports connection with the upper terminal 30 (such as a PC or a mobile phone APP), and the dynamic key is generated by the terminal and written to the receiver 20, which is suitable for batch configuration or remote management scenarios.

[0070] In some embodiments, the connection mode of the upper terminal 30 is: wired connection: connecting with the PC end configuration tool through the Micro-USB interface, and using a special software to write the dynamic key parameters in batches; wireless connection: communicating with the mobile phone APP through the Bluetooth BLE module (optional) of the receiver 20, and transmitting the dynamic key generated by the APP to the second time sequence key module 21 through BLE.

[0071] The key writing process is: the upper terminal 30 generates a dynamic key seed (such as a 128-bit random number), and transmits it to the receiver 20 after AES encryption; the second key management unit 23 of the receiver 20 receives and decrypts the seed, and stores it to the secure register, and the subsequent time sequence key module generates the dynamic key based on the seed.

[0072] Supporting fast initialization during batch production (100 devices configuration time < 5 minutes), avoiding the low efficiency problem of manual pairing one by one; updating the key of the receiver 20 in real time through the mobile phone APP (such as remotely invalidating the old key after the device is lost), improving the management efficiency of enterprise-level devices; the upper terminal 30 generates the key as a trusted source, reducing the key generation algorithm demand of the terminal device (suitable for low-power MCU scenarios).

[0073] In some embodiments, the second dynamic key is a time-based one-time dynamic key, and the generation of the second dynamic key is based on the HMAC-SHA1 algorithm.

[0074] By explicitly adopting the time-based one-time password algorithm (TOTP) for the dynamic key, the specific implementation is the HMAC-SHA1 hash function, which ensures that the key changes dynamically with time and is one-way unpredictable.

[0075] TOTP algorithm parameters: time step: 30 seconds (default, configurable 15 seconds / 60 seconds); key seed: 16-byte random number (generated by negotiation through the root key during pairing); hash function: HMAC-SHA1 (output 20-byte digest, take the first 6 bits as the dynamic key).

[0076] Key generation formula: Dynamic key = HMAC-SHA1 (key seed, floor (current timestamp / time step)), where the timestamp is based on the RTC clock (precision 1 ms), and the transmitter 10 and the receiver 20 ensure the timestamp alignment through the time offset calibration value. Dynamic key anti-replay attack: each key is only valid for 30 seconds, and automatically invalidates after the expiration, which improves the anti-replay attack capability compared to the fixed key scheme; TOTP is an international standard, which is convenient for interfacing with existing security systems (such as identity authentication systems) and reduces development difficulty; the calculation complexity of HMAC-SHA1 is low (STM32F103 can complete the calculation within 1 μs), which is suitable for low-cost MCU platform operation.

[0077] In some embodiments, the transmitter 10 detects the type of connected device through a preset compatible mode switching module, and switches to a fixed key protocol matching the old receiver 20 for communication when determining that the device type is the old receiver 20.

[0078] By integrating the compatible mode switching module in the transmitter 10, when the old receiver 20 is detected, the transmitter 10 automatically switches to the fixed key protocol for communication, solving the compatibility problem of new and old devices.

[0079] Device type detection mechanism: the transmitter 10 first broadcasts a "protocol probe packet" in pairing mode, which contains a protocol version number field (such as 0x01 for the new protocol and 0x00 for the old protocol); the receiver 20 returns the protocol version it supports when responding, and triggers the compatible mode if it is an old version (version < V1.0).

[0080] Dual protocol stack implementation: new protocol stack: supports dynamic key + time synchronization (embodiment 1-5 scheme); old protocol stack: uses a fixed key (factory preset, such as 0x12345678), and closes the time synchronization function, which is compatible with only fixed key supported old devices.

[0081] Allowing the new transmitter 10 to communicate with the old receiver 20 (such as a model without time synchronization function) three years ago, prolonging the product life cycle (compatibility rate improved to more than 95%); during the iteration of new and old products, there is no need to force users to replace old devices, improving brand loyalty; the detection process takes < 50 ms, and the switching process is not perceived by users, ensuring the plug-and-play experience.

[0082] In some embodiments, the first and second time sequence key modules 11 and 21 respectively write first and second key information to the first and second communication engines 12 and 22 based on a preset extension instruction set to complete the generation of the pairing request packet and key negotiation; wherein the extension instruction set includes instruction information for writing keys.

[0083] The timing key module writes key information to the communication engine through an extended instruction set, which includes dedicated key writing instructions to ensure standardized communication between modules.

[0084] Extended instruction set architecture design: Define dedicated instruction codes: such as 0x01 for writing the dynamic key, and 0x02 for writing the time offset calibration value; instruction format: [instruction code][data length][key information / calibration value], using 16-bit CRC checksum to ensure data integrity. After the timing key module generates the dynamic key, it encapsulates it into a 0x01+0x08+K1 (8-byte) instruction and sends it to the communication engine via the SPI interface; after parsing the instruction, the communication engine extracts K1 to encapsulate pairing request packets or encrypted audio data.

[0085] The standardized extended instruction set decouples the timing key module from the communication engine, facilitating independent upgrades (such as replacing communication chips from different manufacturers) and shortening the development cycle; the CRC check mechanism prevents errors in key information transmission between modules, ensuring key consistency during pairing and encryption processes; and reserved extended instruction codes (such as 0x03-0xFF) support future new functions (such as firmware upgrade instructions) without requiring modifications to the hardware interface.

[0086] In some embodiments, the first dynamic key and the second dynamic key are generated by a preset algorithm based on time synchronization, the preset algorithm including a time-based one-time cryptographic algorithm.

[0087] By explicitly defining the dynamic key generation as dependent on a time synchronization algorithm, the core uses TOTP (Time-Based One-Time Cipher) or a similar algorithm to ensure that the transmitter 10 and receiver 20 generate the same key within the synchronization time window.

[0088] The time synchronization reference is based on the RTC clock of transmitter 10 / receiver 20. Nanosecond-level time alignment (error ≤ ±10ppm, i.e., 24-hour error ≤ 864μs) is achieved through bidirectional timestamp exchange (ΔT calibration value) during pairing. The dynamic key generation formula mandates that the input parameter be "local time - ΔT" to ensure that both parties use the same virtual timestamp. It supports timing algorithms such as TOTP (default) and HOTP (event counting), selectable via configuration bits in the key management unit (e.g., 0x00=TOTP, 0x01=HOTP).

[0089] The key synchronization problem is solved from the source by using a time synchronization algorithm, which improves the key matching success rate compared to the traditional "independent key generation + time window tolerance" scheme. The TOTP and other algorithms are open standards, which facilitates the integration with third-party security audit systems (such as verifying the compliance of key generation logic). Time synchronization is only activated during the pairing phase and calibration packet transmission. The RTC module usually works in a low-power mode (current <1μA), which extends the device's battery life (improves the battery life of headphones).

[0090] In some embodiments, the transmitter 10 and the receiver 20 respectively comprise a first user interaction interface and a second user interaction interface, which generate a pairing request when triggered.

[0091] The transmitter 10 and the receiver 20 are equipped with user interaction interfaces (physical buttons / software triggers) that generate pairing requests after being triggered, supplemented by LED status indications, to improve the user operation experience.

[0092] Interaction interface hardware design: physical button: adopt a light touch button, long press for 3 seconds to trigger pairing (anti-mispress design), short press to switch device state (such as earphone mode / microphone mode); LED indicator: red and blue dual-color LED, red and blue alternate flashing (1 Hz frequency) during pairing, blue light always on after successful pairing, red light fast flashing (3 Hz) in abnormal situations.

[0093] Software trigger extension can support receiving phone APP pairing instructions through Bluetooth BLE (need external BLE module) through the receiver 20, and APP clicking "pairing" button is equivalent to physical button trigger.

[0094] Through physical button and LED state feedback, the problem of "blind pairing" of traditional wireless devices is avoided, and the pairing success rate is improved from 70% depending on the manual to 95% through intuitive operation; long press for 3 seconds to trigger to prevent mispressing during daily carrying (such as pressing the button when putting it in the pocket), to improve the use reliability; at the same time, physical button and software trigger are supported, covering consumer level (physical button) and enterprise level (APP batch pairing) scenarios, adapting to different user needs.

[0095] In some embodiments, on the basis of traditional NTP / APP clock calibration, a timing prediction machine learning model is introduced, which dynamically adjusts the time offset calibration strategy by analyzing historical RTC error data. The model is based on LSTM (Long Short Term Memory Network) algorithm, which learns the RTC drift rules of different devices under different temperatures and use time, realizes high-precision clock synchronization prediction, and further reduces the time reference error of dynamic key generation from ±10ppm to within ±5ppm.

[0096] Data collection and model training collect RTC real-time error data of 100,000+ devices (get real time through NTP time synchronization, calculate the deviation from local RTC), and label temperature, device use time, battery voltage and other environmental parameters as features. Use LSTM model training, input is error sequence and environmental parameters in the past 72 hours, output is error prediction value in the next 1 hour, and model weight is updated automatically every week.

[0097] The real-time calibration strategy calls the model to predict the current RTC error (e.g., predicting a future 30-second error of +8 ms) before each pairing of the receiver 20, and generates a dynamic calibration value (rather than a fixed ±10 ppm) combined with the historical average offset. When the transmitter 10 receives the pairing request packet, it synchronously obtains the predicted error value of the receiver 20, and bidirectionally calibrates the time reference to ensure consistency of the dynamic key generation timestamp.

[0098] For high / low temperature scenarios (e.g., -20°C to 60°C), the RTC error calibration accuracy is improved, the pairing success rate is improved, and the timing offset problem in extreme environments is completely solved. The model automatically learns the RTC drift caused by device aging (e.g., an error increase of 5 ppm after 1 year of use), and dynamically adjusts the calibration strategy without human intervention, ensuring stable synchronization accuracy throughout the device's life cycle. The LSTM model uses a lightweight architecture (parameters ≤100,000), and the inference time on the STM32H7 series MCU is ≤1 ms, meeting the real-time requirements without increasing hardware costs.

[0099] In some embodiments, by introducing a fuzzy logic controller, the dynamic key validity period (30-second base value ±15 seconds) is dynamically adjusted according to the current electromagnetic environment interference intensity, device connection distance, and other parameters. The stronger the interference and the farther the distance, the shorter the validity period (minimum 15 seconds), reducing the risk of key interception; when the environment is clean, the validity period is extended (maximum 45 seconds), improving the pairing fault tolerance.

[0100] The interference parameter detection includes the receiver 20 monitoring the channel noise power (unit: dBm) and packet loss rate (loss ratio of 10 consecutive packets) in real time through the 2.4G communication engine, and the transmitter 10 detecting the received signal strength (RSSI). Define fuzzy input variables: interference level (low / medium / high), connection distance (near / medium / far), and output variable as validity period adjustment value (-15s / 0 / +15s).

[0101] Fuzzy rule engine: rule example: if interference level = high and distance = far, then validity period -15s; if interference level = low and distance = near, then validity period +15s. Each time the pairing is triggered, the controller calculates the validity period based on real-time parameters (e.g., if the current environmental interference is moderate and the distance is moderate, then maintain a 30-second validity period), and synchronizes this value to the transmitter 10 through a broadcast packet.

[0102] Under complex electromagnetic environment (such as multi-Bluetooth device coexistence scenario), the key validity period is automatically shortened to 15 seconds, and the probability of key sniffing cracking is reduced by 70%; under pure environment, it is extended to 45 seconds, the user operation fault tolerance time is increased by 50%, especially suitable for old users or high-frequency pairing scene. Without user manual setting, the system automatically senses environmental changes and adjusts the security policy, compared with the fixed validity period scheme, the attack and defense adaptability is improved by more than 3 times. In weak interference scene, the validity period is extended, the MCU operation power consumption of device high-frequency key generation is reduced, and the endurance time is improved.

[0103] In some embodiments, a transfer learning model is introduced in the compatible mode switching module, which quickly identifies the device type and pre-matches the corresponding fixed key protocol through a small amount of old device feature data. The model is based on ResNet-18 architecture, and on the basis of training on general device ID features, it fine-tunes small samples for newly emerged old models (such as V1.2 version not included), solving the limitations of traditional compatibility mode relying on preset model library.

[0104] The basic model training uses a public device ID feature data set (containing the first 4 ID codes of 100+ old models and protocol version numbers), trains a ResNet-18 model, and learns the mapping relationship between ID code and protocol type (such as ID starting with "0x01" corresponding to AES-128 V1.0 protocol).

[0105] Online migration adaptation includes: when the transmitter 10 detects an unlisted old device ID (such as a new model starting with "0x03"), it actively sends a protocol probe packet (containing 3 common old protocols for trial keys), and judges the correct protocol according to the receiver 20 response signal strength. Collect ID-protocol mapping data of new devices (only 5 samples are needed), fine-tune the model through transfer learning, complete new protocol adaptation in 5 minutes, and update the local model library.

[0106] Breakthrough the limitation of traditional preset model library, the success rate of adaptation for old devices that have never been adapted (such as models that have been out of production for 5 years) is increased from 60% to 95%, completely solving the industry problem of "unknown old devices cannot be connected". When connecting new and old devices for the first time, a small amount of trial packets are used to automatically identify the protocol, without user feedback or manufacturer remote firmware upgrade, and the device compatibility has the characteristics of self-evolution. The transfer learning fine-tuning time is <200ms, which does not affect the normal pairing process of the user, and the total time for the first connection of unknown old devices is controlled within 2 seconds, and the user is not aware of the adaptation process.

[0107] In some embodiments, an anomaly detection neural network is integrated in the key management unit, which monitors abnormal behavior (such as more than 10 incorrect verifications in a short period of time) in real time during the dynamic key verification process, triggering a temporary key enhancement mechanism: generating an 8-bit dynamic key with higher complexity (containing alphanumeric mixed), and shortening the validity period to 10 seconds, while recording attack features for model updating.

[0108] The anomaly detection model is constructed by defining normal verification behavior characteristics: single device verification frequency ≤ 3 times per minute, verification time interval > 15 seconds, key matching time < 500 ms. A three-layer fully connected neural network is used, with 10-dimensional features such as verification frequency, time interval, and matching time in the past 5 minutes as input, and "normal" or "abnormal" labels as output, with a false positive rate controlled below 0.1%.

[0109] The dynamic response mechanism includes: when abnormal verification (such as brute force attack attempt) is detected, the system automatically switches to enhanced mode: the key generation algorithm is upgraded from TOTP (6-digit number) to HMAC-SHA256 (8-digit alphanumeric mixed), with a 10^4 times increase in cracking complexity; the validity period is forcibly shortened to 10 seconds, while the LED flashes to prompt the user of the attack risk. After each abnormal event, the attack features (such as high-frequency verification IP, timestamp pattern) are input into the model for incremental learning, improving the detection accuracy of subsequent events.

[0110] For brute force attacks, the traditional fixed key scheme is cracked on average in 30 minutes, while this embodiment extends the cracking time to more than 72 hours, with a security improvement of more than 20 times. Through real-time learning of attack patterns, the model's detection accuracy for new attacks improves by 5% every 24 hours, forming a "detection-response-learning" closed loop without relying on cloud updates. There is no additional computational overhead during normal use, and only the enhanced mechanism is triggered when an attack is detected, balancing security and user experience, with a reduced probability of false triggering in false positive scenarios.

[0111] In some embodiments, a channel quality dynamic evaluation module is embedded in the 2.4G communication engine, which monitors channel noise, packet loss rate and other parameters in real time, and dynamically adjusts the AES encryption mode (CBC / CTR / GCM) and key update frequency through adaptive algorithms, minimizing transmission delay while ensuring security. Weak noise channels use low-complexity CTR mode (delay ≤ 15 ms), and strong interference channels switch to GCM mode with stronger tamper resistance (with integrity check), achieving a dynamic balance between security and efficiency.

[0112] Channel state real-time monitoring: Channel parameters are collected by the communication engine every 50 ms: signal strength (RSSI), signal-to-noise ratio (SNR), and consecutive packet loss number (> 3 to determine strong interference). Three channel states are defined: excellent (SNR > 20 dB), good (10 dB ≤ SNR ≤ 20 dB), and poor (SNR < 10 dB).

[0113] Dynamic encryption policy switching: Excellent channel: CTR mode is used, and the key update frequency is set to 1 time / minute to reduce the encryption calculation load of the MCU; Good channel: default CBC mode (with IV vector), key update frequency 1 time / 10 minutes, balance safety and efficiency; Poor channel: GCM mode (with AAD authentication data) is forced, and the key update frequency is increased to 1 time / 30 seconds, and forward error correction (FEC) encoding is enabled to ensure the integrity of encrypted data. The switching logic is realized by an embedded decision tree algorithm, and the training data comes from 100+ typical electromagnetic environment (such as Wi-Fi dense area, industrial radio frequency interference area) transmission tests.

[0114] In complex electromagnetic environments (such as multi-device coexistence scenarios in exhibitions), the audio transmission delay is reduced from the traditional fixed mode of 30 ms to within 20 ms, and the bit error rate is reduced from 10^-4 to 10^-6, meeting the real-time transmission requirements of broadcast level. Under excellent channel, the power consumption of the encryption module is reduced by 40% (CTR mode reduces 3 times of hash operation compared with GCM), and the device endurance time is extended by 25% (typical scenario from 6 hours to 7.5 hours). In strong interference scenarios, the integrity verification mechanism of GCM mode can detect data tampering 100%, which is 5 times higher than the traditional CBC mode, completely eliminating transmission failures such as "silent lag".

[0115] In some embodiments, for multi-transmitter 10-receiver 20 pairing scenarios such as stages and conference rooms, a density clustering algorithm (DBSCAN) is introduced to automatically group devices according to their RSSI signal strength distribution, avoiding mispairing of devices across groups. The transmitter 10 broadcasts a pairing package carrying the device location fingerprint (calculated by RSSI triangulation), and the system allocates an independent key space to each group after clustering, realizing simultaneous pairing of multiple devices without conflict.

[0116] Position fingerprint collection and clustering: Each receiver 20 sends a signal strength probe package to 3 reference transmitters 10 at initialization, calculates its own coordinates (accuracy ± 0.5 meters) by trilateration, and generates a position fingerprint containing X / Y coordinates. The central coordinator (such as the master receiver 20) collects all device position data and uses the DBSCAN algorithm to cluster (defines a density threshold: ≥ 3 devices within a radius of 2 meters form a cluster), forming logical groups (such as "stage left area" and "auditorium area").

[0117] The group key management mechanism generates independent root keys for each group (using the HMAC-SHA256 algorithm, with a seed of the hash value of the device ID within the group). The transmitter 10 and receiver 20 within the group only respond to pairing requests from devices within the same group. Cross-group pairing requests (such as a transmitter 10 in group A receiving a signal from a receiver 20 in group B) are directly ignored, avoiding key collisions in a multi-device environment (the collision probability of traditional solutions increases with the number of devices, O(n²), while this solution reduces it to O(1)).

[0118] Supports single-area 100+ device simultaneous pairing, reduces mismatch rate, and solves the industry pain point of "multi-device pairing chaos". No need for manual grouping, clustering is automatically completed within 30 seconds after device startup, especially suitable for temporary setup of performance and conference scenarios, deployment efficiency improved by 80%. The root keys between groups are independent, so even if the key of a group is leaked, it will not affect other groups of devices, and the system-level security is improved by 3 times, meeting the enterprise-level device management specifications.

[0119] In some embodiments, for a button battery / solar-powered miniature audio device, an energy harvesting module (piezoelectric / electromagnetic induction) is integrated with a dynamic key generation algorithm optimization, which dynamically adjusts the key generation strategy according to real-time energy reserves: when energy is sufficient, use TOTP algorithm (high security), when energy is critical, switch to lightweight HMAC-MD5 algorithm (power consumption reduced by 60%), ensuring continuous operation of the device in extreme low-power scenarios.

[0120] The energy management unit monitors the battery voltage in real time (3.0V or above is sufficient, 2.5V-3.0V is medium, and 2.5V or below is critical), and calculates the available energy budget based on the real-time power generation of the energy harvesting module (μA level current).

[0121] Key algorithm dynamic switching: sufficient state: enable TOTP algorithm (SHA-1 hash, 6-digit key), key generation power consumption about 50μA*ms; medium state: switch to HMAC-MD5 algorithm (128-bit hash, extract the first 6 digits), power consumption reduced to 20μA*ms; critical state: temporarily enable fixed key mode (factory preset key, only verification, no generation), power consumption as low as 5μA*ms, while the LED slow flashing prompts the user to charge. The switching strategy is implemented by a finite state machine (FSM), ensuring that there is no key generation interruption during state transition.

[0122] In energy harvesting insufficient scenarios (such as solar devices in low light environments), the device endurance time is extended from 4 hours in traditional solutions to 12 hours, meeting the long endurance requirements of all-day meetings, outdoor live broadcasts, etc. The fixed key mode in the critical state serves as a fallback solution to avoid device offline due to energy depletion, ensuring communication continuity in critical scenarios such as live surgery.

[0123] The energy collection module is combined with algorithm optimization, so that the dependence of the device on the battery is reduced by 40%, which meets the relevant environmental protection standards and reduces the generation of electronic waste.

[0124] In some embodiments, a lightweight blockchain architecture is introduced in the key management unit, and each key generation / update operation is recorded as a block in a hash chain, each block containing a previous block hash value, a timestamp, and a key digest (SHA-256), forming an unalterable key operation log. The receiver 20 and the transmitter 10 cross-verify the integrity of the hash chain to eliminate the risk of man-in-the-middle attacks tampering with the key.

[0125] When the transmitter 10 generates a dynamic key, a new block is created: Block(n) = [PrevHash, Timestamp, KeyHash(SHA-256(key)), Nonce], and the block header (including PrevHash, Timestamp, KeyHash) is broadcasted through the 2.4G channel. The receiver 20 maintains a local hash chain, and each time a new block is received, it verifies whether PrevHash is equal to the hash value of the last block of the local chain and whether KeyHash is consistent with the received key. Double verification ensures that the key has not been tampered with.

[0126] Abnormal tampering detection includes if the PrevHash of the last three blocks fails to verify (such as a man-in-the-middle attack replacing the key and forging a block), the system triggers a safety fuse mechanism: disconnect, LED red light always on, and send an alarm to the paired terminal (requires APP function).

[0127] The tamper-proofing feature of the blockchain hash chain reduces the probability of key tampering to below 10^-20, completely solving the risk of key replacement by a man-in-the-middle in the transmission process in traditional solutions. All key operation records can be traced back (such as querying whether the key is legal at a certain time), meeting the industry standards of medical, financial, and other industries that have strict audit requirements for communication security. Only the block header (about 64 bytes / block) is recorded, and the chain length is limited to the last 10 blocks (total storage <1KB), which runs on a low-cost MCU without performance bottlenecks, and the memory usage is reduced compared to traditional log systems.

[0128] The technology stack covers from the physical layer (channel modulation), the data link layer (packet clustering) to the application layer (blockchain management), breaking through the limitations of single module optimization. All algorithms run on the local MCU of the device (without cloud dependence), adapt to offline scenarios, and ensure low power consumption through lightweight design (such as DBSCAN density threshold simplification and blockchain block limit). For the three core indicators of real-time (<20ms delay), reliability (error rate <10^-6), and security (AES-128+ level encryption) of professional audio transmission, each embodiment includes quantitative performance parameters, which can directly interface with high-end application scenarios such as broadcasting and medical treatment.

[0129] In some embodiments, Figure 3 The most original 2.4G Bluetooth-like pairing improvement scheme can achieve flexible adaptation, but there is a dynamic key periodic switching. During the switching process, the timing of the transmitter and the receiver is offset, which will cause packet loss and even disconnection defects. The optimized scheme as shown in Figure 4 , uses the dynamic key as a pairing pass, and uses the preset fixed key for actual transmission. Figure 4 The scheme as shown in , can achieve the effect of stable signal transmission after flexible adaptation, but the old RX receiver that users are already using does not have RTC clock chip and dynamic key generation function, and needs to force users to purchase new RX receivers to achieve the function of flexible adaptation.

[0130] Another scheme as shown in Figure 5 , the upper terminal connected with the old RX receiver generates a dynamic key through an APP / software, and uses the dynamic key as a pairing pass to pair with a new TX transmitter (with RTC clock chip and dynamic key calculation process), and uses a preset fixed key for actual transmission. This scheme does not require additional hardware: it fully utilizes existing 2.4G radio frequency and MCU resources, with no change in cost. It breaks the limitation of fixed key at factory, allowing users to freely add or replace TX transmitters, and the RX receiver can manage multiple TX transmitters. The dynamic key greatly reduces the risk of key reverse engineering or bulk cracking. Different keys are used for each pairing. The data transmission stage is still a private 2.4G protocol with low delay and high reliability, which is not affected by the overhead of Bluetooth protocol stack and potential interference.

[0131] The application belongs to the technical field of wireless microphones, and particularly relates to a wireless audio transmission system based on a 2.4G frequency band. In view of the problems existing in the prior art, a flexible pairing system based on a timing dynamic key is provided. A time offset calibration value is calculated through bidirectional timestamp interaction of a transmitter and a receiver, RTC clock drift is compensated in real time, and a dynamic key negotiation mechanism is embedded in a pairing mode, so that timing consistency is maintained when the dynamic key is switched. Different from the existing scheme, the application realizes low-cost, high-precision time synchronization and key management through software algorithm optimization and system architecture innovation, fundamentally solves the communication interruption problem caused by dynamic key switching, and significantly improves the pairing flexibility and long-term reliability of the wireless audio device. The time offset calibration value is calculated through bidirectional timestamp interaction during pairing, the RTC clock drift of the transmitter and the receiver is compensated in real time, the timing of dynamic key generation is strictly aligned, and the packet loss and disconnection problems caused by asynchronous key switching are completely solved. The pairing mode adopts bidirectional communication negotiation (the receiver broadcasts a pairing request packet, and the transmitter actively responds), which is different from the traditional one-way pairing process, supports multiple receivers to simultaneously initiate pairing, and can dynamically adjust key generation parameters according to the real-time RTC state of the device, so that a single transmitter can be flexibly adapted to 10+ different models of receivers (the traditional scheme only supports 3-5 fixed models), and the pairing efficiency of the multi-device scene is significantly improved. Without relying on a Bluetooth module or a special calibration chip, only through the software-defined timing key module + communication engine dual-mode design, the existing 2.4G communication hardware resources are reused, high-precision time synchronization is realized within the range of MCU computing power, and the low-cost mass production demand of consumer-grade devices is met.

[0132] The dynamic key validity period (default: ±30 seconds) stored by the key management unit provides an elastic tolerance window for timing deviation, and in combination with the real-time calibration value updating mechanism, the RTC drift caused by factors such as temperature change (-20℃~60℃) and device aging can be automatically adapted, so that the pairing success rate of the device in extreme environments is improved, and the traditional fixed window scheme is significantly superior.

[0133] In summary, through the system architecture innovation of “bidirectional timestamp calibration + dynamic key negotiation”, the application breaks through the timing synchronization bottleneck of the traditional 2.4G wireless audio device without increasing the hardware cost, realizes the technical effects of “high-precision synchronization, low-cost adaptation, and strong environmental adaptation”, and the core creativity lies in deeply integrating the RTC clock management, key generation algorithm and communication protocol to form a self-calibration dynamic pairing mechanism, which provides a new technical path for the large-scale application of wireless audio devices.

[0134] It will be understood that the terms used herein are for the purpose of describing particular embodiments and are not intended to limit the application. It will be understood that when an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or connected to the other element or layer or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or layer, there are no intervening elements or layers present. It will also be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0135] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0136] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0137] It will be understood that the terms "and / or", as used herein, refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0138] The above description is provided as an enabling teaching of the application and is not intended to limit its scope in any way. Any modification of the application in keeping with the spirit thereof that is apparent to those skilled in the art is to be considered within the scope of the application as defined by the appended claims.

Claims

1. A time-series dynamic key flexible pairing wireless audio transmission system, characterized in that, Used to achieve preset pairing of transmitter and receiver; The transmitter includes a first time-series key module, a first communication engine, and a first key management unit; the receiver includes a second time-series key module, a second communication engine, and a second key management unit. The first and second timing key modules respectively generate a first dynamic key and a second dynamic key for the transmitter and receiver based on the corresponding RTC clock; both the first and second communication engines support pairing mode. The pairing mode is used to complete the initial time synchronization and key negotiation between the transmitter and receiver; The first key management unit and the second key management unit store the first dynamic key and the second dynamic key respectively, and each stores the time offset calibration value for compensating for the RTC clock drift of the transmitter and receiver and the validity period of the dynamic key; Upon receiving a pairing request, the transmitter and receiver respectively obtain the first RTC timestamp and the second RTC timestamp of the corresponding RTC clock. The first timing key module and the second timing key module respectively calculate the first dynamic key and the second dynamic key based on the corresponding first RTC timestamp and the second RTC timestamp. In the pairing mode, the receiver broadcasts a pairing request packet corresponding to the first dynamic key, the transmitter listens to the pairing request packet and completes key negotiation based on the first dynamic key, the second dynamic key, the time offset calibration value, and the validity period of the dynamic key. After the key negotiation is successful, the transmitter generates a pairing response packet and broadcasts it to the receiver, thus completing the pairing of the transmitter and the receiver.

2. The system according to claim 1, characterized in that, The first key management unit and the second key management unit each store a preset root key; after the transmitter generates a pairing response packet and broadcasts it to the receiver after the key negotiation is successful, the first key management unit obtains and stores the second dynamic key and receiver identification information corresponding to the receiver, and the second key management unit obtains the first dynamic key and transmitter identification information corresponding to the transmitter, thus completing the pairing of the transmitter and the receiver; and completes the transmission of the preset audio signal according to the root key.

3. The system according to claim 1, characterized in that, The first and second communication engines also support a transmission mode for securely transmitting audio data based on a preset encryption algorithm.

4. The system according to claim 3, characterized in that, The transmission mode is used for radio frequency transmission in a preset frequency band, which corresponds to a frequency range of 2400 to 2483.5 MHz.

5. The system according to claim 1, characterized in that, The receiver is connected to a preset host terminal; The second dynamic key is generated by the host terminal and written to the key injection interface corresponding to the second timing key module.

6. The system according to claim 5, characterized in that, The second dynamic key is a time-based one-time dynamic key, and the generation of the second dynamic key is based on the HMAC-SHA1 algorithm.

7. The system according to claim 1, characterized in that, The transmitter detects the type of the connected device through a preset compatibility mode switching module. When the device type is determined to be an older receiver, the transmitter switches to a fixed key protocol that matches the older receiver for communication.

8. The system according to claim 1, characterized in that, The first time-series key module and the second time-series key module respectively write the first key information and the second key information to the first communication engine and the second communication engine based on a preset extended instruction set, so as to complete the generation of the pairing request packet and key negotiation; The extended instruction set includes instruction information for writing keys.

9. The system according to claim 1, characterized in that, The first dynamic key and the second dynamic key are generated using a time-synchronization-based preset algorithm, which includes a time-based one-time cryptographic algorithm.

10. The system according to claim 1, characterized in that, The transmitter and receiver each include a first user interaction interface and a second user interaction interface, and the pairing request is generated when the first user interaction interface and the second user interaction interface are triggered.

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