Patent Description:
With the development of wireless communications technologies, people have become accustomed to connecting different intelligent terminal devices in a wireless manner. As a mature short-range wireless communications technology at present, a Bluetooth technology is widely used in intelligent terminal devices, for example, a connection between a smartphone and a Bluetooth device such as a Bluetooth headset or a Bluetooth speaker through Bluetooth.

Currently, true wireless stereo (true wireless stereo, TWS) Bluetooth headsets are developed rapidly. A TWS headset includes a primary earbud and a secondary earbud. Terminals such as a mobile phone and a tablet may be connected to the primary earbud, and then the primary earbud is connected to the secondary earbud through Bluetooth, to achieve true Bluetooth wireless separation of audio-left and audio-right channels for use. When the two earbuds of the TWS headset are in a charging case, a Bluetooth connection between the two earbuds is first completed when a user opens the charging case for use. Then, the primary earbud is connected to a terminal. When the user opens the charging case again after the TWS headset is used and only one earbud is placed into the charging case, the earbud in the charging case reconnects to the other earbud. If the other earbud is not around the charging case or is lost, the earbud in the charging case reconnects to the terminal only after connecting to the other earbud expires. As a result, the earbud in the charging case takes a long time to reconnect to the terminal and work properly, which is not good for user experience.

<CIT> relates to system comprising wireless earbud and a charging case, the system shows host device interconnected via Bluetooth transceivers BT TX/RX <NUM>/<NUM> to wireless headphones <NUM>; intermediate device <NUM> (e.g., a case for the headphones), headphones are mated with the intermediate device (e.g., stored in a case). Wired input/output <NUM> can be used for charging wireless headphones <NUM> and/or communicating data with intermediate device <NUM>; the processor <NUM> can be configured to communicate with a pair of earplugs 202a, 202b to turn on its radio frequency when the cover is in the open position (e.g., in response to receiving an "open" signal) so that it is ready for use by the user, and Turn off the radio when the lid is in the closed position (for example, in response to receiving a "close" signal) to save its power.

<CIT> relates to a Bluetooth headset charging case system, the charging case system includes a Bluetooth headset and a charging case, and a first GND contact and a first VCHG contact are disposed on the Bluetooth headset; a second GND contact and a second VCHG contact are disposed in the charging case, and when the Bluetooth headset is disposed in the charging case, the first VCHG contact is in contact with the second VCHG contact; and the charging case charges the Bluetooth headset by using the first VCHG contact and the second VCHG contact that are in contact with each other, and the charging case and the Bluetooth headset reuse the first VCHG contact that is in contact with each other to communicate with the second VCHG contact.

This application provides a Bluetooth paging method according to claim <NUM> and a corresponding system according to claim <NUM>. Further embodiments are set out in the dependent claims.

The following clearly describes the technical solutions in embodiments of this application in detail with reference to the accompanying drawings. In descriptions of embodiments of this application, unless otherwise stated, "/" indicates "or". For example, A/B may indicate A or B. The term "and/or" in this specification merely describes an association relationship for describing associated objects, and indicates that three relationships may exist. For example, A and/or B may indicate the following three cases: Only A exists, both A and B exist, and only B exists. In addition, in the descriptions of embodiments of this application, "a plurality of" means two or more.

The terms "first" and "second" mentioned below are merely intended for description, and shall not be understood as an indication or implication of relative importance or implicit indication of a quantity of indicated technical features. Therefore, a feature limited by "first" or "second" may explicitly or implicitly include one or more features. In the descriptions of embodiments of this application, unless otherwise specified, "a plurality of" means two or more.

The following describes a system architecture provided in an embodiment of this application.

<FIG> is a schematic diagram of an architecture of a system <NUM> according to an embodiment of this application. As shown in <FIG>, the system <NUM> may include a terminal <NUM> and a Bluetooth device <NUM>.

The terminal <NUM> may communicate with the Bluetooth device <NUM> by using a Bluetooth technology (including basic rate (basic rate, BR)/enhanced data rate (enhanced data rate, EDR) Bluetooth and Bluetooth low energy (Bluetooth low energy, BLE)). The terminal <NUM> may be a device such as a smartphone, a media player (for example, an MP3 or an MP4), a tablet computer, a personal digital assistant (personal digital assistant, PDA), a television, or a smart watch.

In this embodiment of this application, the Bluetooth device <NUM> may be a true wireless stereo (true wireless stereo, TWS) headset. The Bluetooth device <NUM> includes two earbuds (also referred to as earbuds) respectively worn on a left ear and a right ear of a user. The two earbuds may be placed into a charging case for charging. When the Bluetooth device <NUM> is no longer used, the Bluetooth device <NUM> may be placed into the charging case for charging. The charging case may communicate with the Bluetooth device <NUM>, to implement operations such as forced pairing, power-on/off of the Bluetooth device <NUM>. A charging interface and a communications interface between the Bluetooth device <NUM> and the charging case may exist independently or may be combined together.

<FIG> is a schematic diagram of a structure of a terminal <NUM>.

The terminal <NUM> is used as an example below to describe embodiments in detail. It should be understood that the terminal <NUM> shown in <FIG> is merely an example, and the terminal <NUM> may have more or fewer components than those shown in <FIG>, may combine two or more components, or may have different component configurations. Various components shown in the figure may be implemented in hardware that includes one or more signal processing and/or application-specific integrated circuits, software, or a combination of hardware and software.

The terminal <NUM> may include a processor <NUM>, an external memory interface <NUM>, an internal memory <NUM>, a universal serial bus (universal serial bus, USB) port <NUM>, a charging management module <NUM>, a power management module <NUM>, a battery <NUM>, an antenna <NUM>, an antenna <NUM>, a mobile communications module <NUM>, a wireless communications module <NUM>, an audio module <NUM>, a speaker 170A, a receiver 170B, a microphone 170C, a headset jack 170D, a sensor module <NUM>, a button <NUM>, a motor <NUM>, an indicator <NUM>, a camera <NUM>, a display <NUM>, a subscriber identification module (subscriber identification module, SIM) card interface <NUM>, and the like. The sensor module <NUM> may include a pressure sensor 180A, a gyro sensor 180B, a barometric pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, an optical proximity sensor <NUM>, a fingerprint sensor <NUM>, a temperature sensor 180J, a touch sensor <NUM>, an ambient light sensor <NUM>, a bone conduction sensor <NUM>, and the like.

It may be understood that the structure shown in this embodiment of the present invention does not constitute a specific limitation on the terminal <NUM>. In some other embodiments of this application, the terminal <NUM> may include more or fewer components than those shown in the figure, or combine some components, or split some components, or have different component arrangements. The components shown in the figure may be implemented by hardware, software, or a combination of the software and the hardware.

The processor <NUM> may include one or more processing units. For example, the processor <NUM> may include an application processor (application processor, AP), a modem processor, a graphics processing unit (graphics processing unit, GPU), an image signal processor (image signal processor, ISP), a controller, a memory, a video codec, a digital signal processor (digital signal processor, DSP), a baseband processor, a neural-network processing unit (neural-network processing unit, NPU), and/or the like. Different processing units may be independent devices, or may be integrated into one or more processors.

The controller may be a nerve center and a command center of the terminal <NUM>. The controller may generate an operation control signal based on instruction operation code and a time sequence signal, to complete control of instruction fetching and instruction execution.

A memory may be further disposed in the processor <NUM>, and is configured to store instructions and data. In some embodiments, the memory in the processor <NUM> is a cache. The memory may store instructions or data just used or cyclically used by the processor <NUM>. If the processor <NUM> needs to use the instructions or the data again, the processor <NUM> may directly invoke the instructions or the data from the memory. This avoids repeated access and reduces a waiting time of the processor <NUM>, to improve system efficiency.

The interface may include an inter-integrated circuit (inter-integrated circuit, I2C) interface, an inter-integrated circuit sound (inter-integrated circuit sound, I2S) interface, a pulse code modulation (pulse code modulation, PCM) interface, a universal asynchronous receiver/transmitter (universal asynchronous receiver/transmitter, UART) interface, a mobile industry processor interface (mobile industry processor interface, MIPI), a general-purpose input/output (general-purpose input/output, GPIO) interface, a subscriber identification module (subscriber identification module, SIM) interface, a universal serial bus (universal serial bus, USB) interface, and/or the like.

The I2C interface is a two-way synchronous serial bus, including a serial data line (serial data line, SDA) and a serial clock line (serial clock line, SCL). In some embodiments, the processor <NUM> may include a plurality of groups of I2C buses. The processor <NUM> may be separately coupled to the touch sensor <NUM>, a charger, a flash, the camera <NUM>, and the like through different I2C bus interfaces. For example, the processor <NUM> may be coupled to the touch sensor <NUM> through the I2C interface, so that the processor <NUM> communicates with the touch sensor <NUM> through the I2C bus interface, to implement a touch function of the terminal <NUM>.

The I2S interface may be used for audio communication. In some embodiments, the processor <NUM> may include a plurality of groups of I2S buses. The processor <NUM> may be coupled to the audio module <NUM> through the I2S bus, to implement communication between the processor <NUM> and the audio module <NUM>. In some embodiments, the audio module <NUM> may transfer an audio signal to the wireless communications module <NUM> through the I2S interface, to implement a function of answering a call through a Bluetooth headset.

The PCM interface may also be configured to: perform audio communication, and sample, quantize, and code an analog signal. In some embodiments, the audio module <NUM> may be coupled to the wireless communications module <NUM> through a PCM bus interface. In some embodiments, the audio module <NUM> may alternatively transfer an audio signal to the wireless communications module <NUM> through the PCM interface, to implement a function of answering a call through a Bluetooth headset. Both the I2S interface and the PCM interface may be used for audio communication.

The UART interface is a universal serial data bus, and is used for asynchronous communication. The bus may be a two-way communications bus. The bus converts to-be-transmitted data between serial communication and parallel communication. In some embodiments, the UART interface is usually configured to connect the processor <NUM> to the wireless communications module <NUM>. For example, the processor <NUM> communicates with a Bluetooth module in the wireless communications module <NUM> through the UART interface, to implement a Bluetooth function. In some embodiments, the audio module <NUM> may transfer an audio signal to the wireless communications module <NUM> through the UART interface, to implement a function of playing music through a Bluetooth headset.

The MIPI interface may be configured to connect the processor <NUM> to a peripheral component such as the display <NUM> or the camera <NUM>. The MIPI interface includes a camera serial interface (camera serial interface, CSI), a display serial interface (display serial interface, DSI), and the like. In some embodiments, the processor <NUM> communicates with the camera <NUM> through the CSI interface, to implement a photographing function of the terminal <NUM>. The processor <NUM> communicates with the display <NUM> through the DSI interface, to implement a display function of the terminal <NUM>.

The GPIO interface may be configured by using software. The GPIO interface may be configured as a control signal or a data signal. In some embodiments, the GPIO interface may be configured to connect the processor <NUM> to the camera <NUM>, the display <NUM>, the wireless communications module <NUM>, the audio module <NUM>, the sensor module <NUM>, or the like. The GPIO interface may alternatively be configured as an I2C interface, an I2S interface, a UART interface, an MIPI interface, or the like.

The USB port <NUM> is a port that conforms to USB standard specifications, and may be specifically a mini USB port, a micro USB port, a USB Type-C port, or the like. The USB port <NUM> may be configured to connect to a charger to charge the terminal <NUM>, may be configured to transmit data between the terminal <NUM> and a peripheral device, or may be configured to connect to a headset, to play audio through a headset. The port may be further configured to connect to another terminal such as an AR device.

It may be understood that an interface connection relationship between the modules that is shown in this embodiment of the present invention is merely an example for description, and does not constitute a limitation on the structure of the terminal <NUM>. In some other embodiments of this application, the terminal <NUM> may alternatively use an interface connection manner different from that in the foregoing embodiment, or a combination of a plurality of interface connection manners.

The charging management module <NUM> is configured to receive a charging input from the charger. The charger may be a wireless charger or a wired charger. In some embodiments of wired charging, the charging management module <NUM> may receive a charging input from the wired charger through the USB port <NUM>. In some embodiments of wireless charging, the charging management module <NUM> may receive a wireless charging input by using a wireless charging coil of the terminal <NUM>. When charging the battery <NUM>, the charging management module <NUM> may further supply power to the terminal by using the power management module <NUM>.

The power management module <NUM> is configured to connect the battery <NUM> and the charging management module <NUM> to the processor <NUM>. The power management module <NUM> receives an input of the battery <NUM> and/or the charging management module <NUM>, and supplies power to the processor <NUM>, the internal memory <NUM>, an external memory, the display <NUM>, the camera <NUM>, the wireless communications module <NUM>, and the like. The power management module <NUM> may be further configured to monitor parameters such as a battery capacity, a battery cycle count, and a battery health status (electric leakage or impedance). In some other embodiments, the power management module <NUM> may alternatively be disposed in the processor <NUM>. In some other embodiments, the power management module <NUM> and the charging management module <NUM> may alternatively be disposed in a same device.

A wireless communication function of the terminal <NUM> may be implemented by using the antenna <NUM>, the antenna <NUM>, the mobile communications module <NUM>, the wireless communications module <NUM>, the modem processor, the baseband processor, and the like.

The antenna <NUM> and the antenna <NUM> are configured to: transmit and receive electromagnetic wave signals. Each antenna in the terminal <NUM> may be configured to cover one or more communications frequency bands. Different antennas may further be multiplexed, to improve antenna utilization. For example, the antenna <NUM> may be multiplexed as a diversity antenna in a wireless local area network. In some other embodiments, an antenna may be used in combination with a tuning switch.

The mobile communications module <NUM> can provide a wireless communications solution that is applied to the terminal <NUM> and that includes <NUM>/<NUM>/<NUM>/<NUM> or the like. The mobile communications module <NUM> may include at least one filter, a switch, a power amplifier, a low noise amplifier (low noise amplifier, LNA), and the like. The mobile communications module <NUM> may receive an electromagnetic wave through the antenna <NUM>, perform processing such as filtering and amplification on the received electromagnetic wave, and transmit a processed electromagnetic wave to the modem processor for demodulation. The mobile communications module <NUM> may further amplify a signal modulated by the modem processor, and convert an amplified signal into an electromagnetic wave for radiation through the antenna <NUM>. In some embodiments, at least some functional modules of the mobile communications module <NUM> may be disposed in the processor <NUM>. In some embodiments, at least some functional modules of the mobile communications module <NUM> and at least some modules of the processor <NUM> may be disposed in a same device.

The modem processor may include a modulator and a demodulator. The modulator is configured to modulate a to-be-sent low-frequency baseband signal into a medium-high-frequency signal. The demodulator is configured to demodulate a received electromagnetic wave signal into a low-frequency baseband signal. Then, the demodulator transmits the low-frequency baseband signal obtained through demodulation to the baseband processor for processing. After being processed by the baseband processor, the low-frequency baseband signal is transmitted to the application processor. The application processor outputs a sound signal by using an audio device (which is not limited to the speaker 170A, the receiver 170B, or the like), or displays an image or a video on the display <NUM>. In some embodiments, the modem processor may be an independent component. In some other embodiments, the modem processor may be independent of the processor <NUM>, and is disposed in a same device as the mobile communications module <NUM> or another functional module.

The wireless communications module <NUM> may provide a wireless communications solution that is applied to the terminal <NUM> and that includes a wireless local area network (wireless local area network, WLAN) (for example, a wireless fidelity (wireless fidelity, Wi-Fi) network), Bluetooth (Bluetooth, BT), a global navigation satellite system (global navigation satellite system, GNSS), frequency modulation (frequency modulation, FM), a near field communication (near field communication, NFC) technology, an infrared (infrared, IR) technology, or the like. The wireless communications module <NUM> may be one or more components integrating at least one communication processor module. The wireless communications module <NUM> receives an electromagnetic wave through the antenna <NUM>, performs frequency modulation and filtering processing on an electromagnetic wave signal, and sends a processed signal to the processor <NUM>. The wireless communications module <NUM> may further receive a to-be-sent signal from the processor <NUM>, perform frequency modulation and amplification on the signal, and convert a processed signal into an electromagnetic wave for radiation through the antenna <NUM>.

In some embodiments, in the terminal <NUM>, the antenna <NUM> is coupled to the mobile communications module <NUM>, and the antenna <NUM> is coupled to the wireless communications module <NUM>, so that the terminal <NUM> can communicate with a network and another device by using a wireless communications technology. The wireless communications technology may include a global system for mobile communications (global system for mobile communications, GSM), a general packet radio service (general packet radio service, GPRS), code division multiple access (code division multiple access, CDMA), wideband code division multiple access (wideband code division multiple access, WCDMA), time-division code division multiple access (time-division code division multiple access, TD-CDMA), long term evolution (long term evolution, LTE), BT, a GNSS, a WLAN, NFC, FM, an IR technology, and/or the like. The GNSS may include a global positioning system (global positioning system, GPS), a global navigation satellite system (global navigation satellite system, GLONASS), a BeiDou navigation satellite system (BeiDou navigation satellite system, BDS), a quasi-zenith satellite system (quasi-zenith satellite system, QZSS), and/or a satellite based augmentation system (satellite based augmentation system, SBAS).

The terminal <NUM> implements a display function through the GPU, the display <NUM>, the application processor, and the like. The GPU is a microprocessor for image processing, and is connected to the display <NUM> and the application processor. The GPU is configured to: perform mathematical and geometric calculation, and render an image. The processor <NUM> may include one or more GPUs that execute program instructions to generate or change display information.

The display <NUM> is configured to display an image, a video, and the like. The display <NUM> includes a display panel. The display panel may be a liquid crystal display (liquid crystal display, LCD), an organic light-emitting diode (organic light-emitting diode, OLED), an active-matrix organic light emitting diode (active-matrix organic light emitting diode, AMOLED), a flexible light-emitting diode (flexible light-emitting diode, FLED), a mini-LED, a micro-LED, a micro-OLED, a quantum dot light emitting diode (quantum dot light emitting diode, QLED), or the like. In some embodiments, the terminal <NUM> may include one or N displays <NUM>, where N is a positive integer greater than <NUM>.

The terminal <NUM> can implement a photographing function by using the ISP, the camera <NUM>, the video codec, the GPU, the display <NUM>, the application processor, and the like.

The ISP is configured to process data fed back by the camera <NUM>. For example, during photographing, a shutter is pressed, light is transmitted to a photosensitive element of the camera through a lens, an optical signal is converted into an electrical signal, and the photosensitive element of the camera transmits the electrical signal to the ISP for processing, to convert the electrical signal into a visible image. The ISP may further perform algorithm optimization on noise, brightness, and complexion of the image. The ISP may further optimize parameters such as exposure and a color temperature of a photographing scenario. In some embodiments, the ISP may be disposed in the camera <NUM>.

The camera <NUM> is configured to capture a static image or a video. An optical image of an object is generated through the lens, and is projected onto the photosensitive element. The photosensitive element may be a charge coupled device (charge coupled device, CCD) or a complementary metal-oxide-semiconductor (complementary metal-oxide-semiconductor, CMOS) phototransistor. The photosensitive element converts an optical signal into an electrical signal, and then transmits the electrical signal to the ISP for converting the electrical signal into a digital image signal. The ISP outputs the digital image signal to the DSP for processing. The DSP converts the digital image signal into an image signal in a standard format such as RGB or YUV. In some embodiments, the terminal <NUM> may include one or N cameras <NUM>, where N is a positive integer greater than <NUM>.

The digital signal processor is configured to process a digital signal, and may further process another digital signal in addition to the digital image signal. For example, when the terminal <NUM> selects a frequency, the digital signal processor is configured to perform Fourier transform, and the like on frequency energy.

The video codec is configured to: compress or decompress a digital video. The terminal <NUM> may support one or more video codecs. In this way, the terminal <NUM> can play or record videos in a plurality of coding formats, for example, moving picture experts group (moving picture experts group, MPEG)-<NUM>, MPEG-<NUM>, MPEG-<NUM>, and MPEG-<NUM>.

The NPU is a neural-network (neural-network, NN) computing processor, quickly processes input information by referring to a structure of a biological neural network, for example, by referring to a transfer mode between human brain neurons, and may further continuously perform self-learning. Applications such as intelligent cognition of the terminal <NUM> may be implemented by using the NPU, for example, image recognition, facial recognition, speech recognition, and text understanding.

The external memory interface <NUM> may be configured to be connected to an external storage card such as a micro SD card, to extend a storage capability of the terminal <NUM>. The external storage card communicates with the processor <NUM> through the external memory interface <NUM>, to implement a data storage function. For example, files such as music and videos are stored in the external storage card.

The internal memory <NUM> may be configured to store computer-executable program code. The executable program code includes instructions. The processor <NUM> runs the instructions stored in the internal memory <NUM>, to implement various function applications and data processing of the terminal <NUM>. The internal memory <NUM> may include a program storage area and a data storage area. The program storage area may store an operating system, an application required by at least one function (for example, a sound playing function or an image playing function), and the like. The data storage area may store data (for example, audio data and an address book) created during use of the terminal <NUM>, and the like. In addition, the internal memory <NUM> may include a high-speed random access memory, and may further include a nonvolatile memory, for example, at least one magnetic disk storage device, a flash memory device, or a universal flash storage (universal flash storage, UFS).

The terminal <NUM> may implement audio functions such as music playing and recording through the audio module <NUM>, the speaker 170A, the receiver 170B, the microphone 170C, the headset jack 170D, the application processor, and the like.

The audio module <NUM> is configured to convert digital audio information into an analog audio signal output, and is also configured to convert an analog audio input into a digital audio signal. The audio module <NUM> may be further configured to: code and decode an audio signal. In some embodiments, the audio module <NUM> may be disposed in the processor <NUM>, or some functional modules of the audio module <NUM> are disposed in the processor <NUM>.

The speaker 170A, also referred to as a "horn", is configured to convert an audio electrical signal into a sound signal. The terminal <NUM> may listen to music by using the speaker 170A, or listen to a hands-free call.

The receiver 170B, also referred to as an "earpiece", is configured to convert an audio electrical signal into a sound signal. When a call is answered or audio information is listened to by using the terminal <NUM>, the receiver 170B may be put close to a human ear to listen to a voice.

The microphone 170C, also referred to as a "mike" or a "mic", is configured to convert a sound signal into an electrical signal. When making a call or sending voice information, the user may make a sound near the microphone 170C through the mouth, to enter a sound signal to the microphone 170C. At least one microphone 170C may be disposed in the terminal <NUM>. In some other embodiments, two microphones 170C may be disposed in the terminal <NUM>, to collect a sound signal and further implement a noise reduction function. In some other embodiments, three, four, or more microphones 170C may alternatively be disposed in the terminal <NUM>, to collect a sound signal, reduce noise, further identify a sound source, implement a directional recording function, and the like.

The headset jack 170D is configured to connect to a wired headset. The headset jack 170D may be a USB port <NUM>, or may be a <NUM> open mobile terminal platform (open mobile terminal platform, OMTP) standard interface or a cellular telecommunications industry association of the USA (cellular telecommunications industry association of the USA, CTIA) standard interface.

The pressure sensor 180A is configured to sense a pressure signal, and can convert the pressure signal into an electrical signal. In some embodiments, the pressure sensor 180A may be disposed on the display <NUM>. There are a plurality of types of pressure sensors 180A, such as a resistive pressure sensor, an inductive pressure sensor, and a capacitive pressure sensor. The capacitive pressure sensor may include at least two parallel plates made of conductive materials. When a force is applied to the pressure sensor 180A, capacitance between electrodes changes. The terminal <NUM> determines pressure intensity based on a capacitance change. When a touch operation is performed on the display <NUM>, the terminal <NUM> detects intensity of the touch operation by using the pressure sensor 180A. The terminal <NUM> may also calculate a touch location based on a detection signal of the pressure sensor 180A. In some embodiments, touch operations that are performed at a same touch location but have different touch operation intensity may correspond to different operation instructions. For example, when a touch operation whose touch operation intensity is less than a first pressure threshold is performed on a Messages icon, an instruction for viewing an SMS message is executed. When a touch operation whose touch operation intensity is greater than or equal to a first pressure threshold is performed on a Messages icon, an instruction for creating a new SMS message is executed.

The gyro sensor 180B may be configured to determine a moving posture of the terminal <NUM>. In some embodiments, angular velocities of the terminal <NUM> around three axes (namely, x, y, and z axes) may be determined by using the gyro sensor 180B. The gyro sensor 180B may be configured to perform image stabilization during photographing. For example, when the shutter is pressed, the gyro sensor 180B detects an angle at which the terminal <NUM> jitters, calculates, based on the angle, a distance for which a lens module needs to compensate, and allows the lens to cancel the jitter of the terminal <NUM> through reverse motion, to implement image stabilization. The gyro sensor 180B may be further used in a navigation scenario and a motion-sensing game scenario.

The barometric pressure sensor 180C is configured to measure barometric pressure. In some embodiments, the terminal <NUM> calculates an altitude by using a value of the barometric pressure measured by the barometric pressure sensor 180C, to assist in positioning and navigation.

The magnetic sensor 180D includes a Hall effect sensor. The terminal <NUM> may detect opening and closing of a flip cover by using the magnetic sensor 180D. In some embodiments, when the terminal <NUM> is a clamshell phone, the terminal <NUM> may detect opening and closing of a flip cover based on the magnetic sensor 180D. Further, a feature such as automatic unlocking upon opening of the flip cover is set based on a detected opening or closing state of the flip cover.

The acceleration sensor 180E may detect magnitudes of accelerations in various directions (usually on three axes) of the terminal <NUM>. When the terminal <NUM> is still, a magnitude and a direction of gravity may be detected. The acceleration sensor 180E may be further configured to identify a terminal posture, and is applied to an application such as switching between landscape mode and portrait mode or a pedometer.

The distance sensor 180F is configured to measure a distance. The terminal <NUM> may measure a distance through infrared light or a laser. In some embodiments, in a photographing scenario, the terminal <NUM> may use the distance sensor 180F to measure a distance, to implement fast focusing.

The optical proximity sensor <NUM> may include, for example, a light-emitting diode (LED) and an optical detector such as a photodiode. The light-emitting diode may be an infrared light-emitting diode. The terminal <NUM> emits infrared light by using the light-emitting diode. The terminal <NUM> detects infrared reflected light from a nearby object by using the photodiode. When sufficient reflected light is detected, it may be determined that there is an object near the terminal <NUM>. When insufficient reflected light is detected, the terminal <NUM> may determine that there is no object near the terminal <NUM>. The terminal <NUM> may detect, by using the optical proximity sensor <NUM>, that the terminal <NUM> held by the user is close to an ear for a call, to automatically turn off a screen to save power. The optical proximity sensor <NUM> may also be used in a smart cover mode or a pocket mode to automatically perform screen unlocking or locking.

The ambient light sensor <NUM> is configured to sense ambient light brightness. The terminal <NUM> may adaptively adjust brightness of the display <NUM> based on the sensed ambient light brightness. The ambient light sensor <NUM> may also be configured to automatically adjust white balance during photographing. The ambient light sensor <NUM> may also cooperate with the optical proximity sensor <NUM> to detect whether the terminal <NUM> is in a pocket to prevent a false touch.

The fingerprint sensor <NUM> is configured to collect a fingerprint. The terminal <NUM> may use a feature of the collected fingerprint to implement fingerprint-based unlocking, application lock access, fingerprint-based photographing, fingerprint-based call answering, and the like.

The temperature sensor 180J is configured to detect a temperature. In some embodiments, the terminal <NUM> executes a temperature processing policy by using the temperature detected by the temperature sensor 180J. For example, when the temperature reported by the temperature sensor 180J exceeds a threshold, the terminal <NUM> lowers performance of a processor located near the temperature sensor 180J, to reduce power consumption to implement thermal protection. In some other embodiments, when the temperature is less than another threshold, the terminal <NUM> heats the battery <NUM> to prevent the terminal <NUM> from being shut down abnormally because of a low temperature. In some other embodiments, when the temperature is less than still another threshold, the terminal <NUM> boosts an output voltage of the battery <NUM> to avoid abnormal shutdown caused by a low temperature.

The touch sensor <NUM> is also referred to as a "touch panel". The touch sensor <NUM> may be disposed on the display <NUM>, and the touch sensor <NUM> and the display <NUM> form a touchscreen. The touch sensor <NUM> is configured to detect a touch operation performed on or near the touch sensor <NUM>. The touch sensor may transfer the detected touch operation to the application processor, to determine a type of a touch event. A visual output related to the touch operation may be provided through the display <NUM>. In some other embodiments, the touch sensor <NUM> may also be disposed on a surface of the terminal <NUM> at a location different from that of the display <NUM>.

The bone conduction sensor <NUM> may obtain a vibration signal. In some embodiments, the bone conduction sensor <NUM> may obtain a vibration signal of a vibration bone of a human vocal-cord part. The bone conduction sensor <NUM> may also be in contact with a human pulse, and receive a blood pressure beating signal. In some embodiments, the bone conduction sensor <NUM> may alternatively be disposed in the headset, to constitute a bone conduction headset. The audio module <NUM> may obtain a voice signal through parsing based on the vibration signal that is of the vibration bone of the vocal-cord part and that is obtained by the bone conduction sensor <NUM>, to implement a voice function. The application processor may parse heart rate information based on the blood pressure beating signal obtained by the bone conduction sensor <NUM>, to implement a heart rate detection function.

The button <NUM> includes a power button, a volume button, and the like. The button <NUM> may be a mechanical button, or may be a touch button. The terminal <NUM> may receive a key input, and generate a key signal input related to a user setting and function control of the terminal <NUM>.

The motor <NUM> may generate a vibration prompt. The motor <NUM> may be configured to provide an incoming call vibration prompt or a touch vibration feedback. For example, touch operations performed on different applications (for example, photographing and audio playing) may correspond to different vibration feedback effects. The motor <NUM> may also correspond to different vibration feedback effects for touch operations performed on different areas of the display <NUM>. Different application scenarios (for example, a time reminder, information receiving, an alarm, a game) may also correspond to different vibration feedback effects. A touch vibration feedback effect may be further customized.

The SIM card interface <NUM> is configured to connect to a SIM card. The SIM card may be inserted into the SIM card interface <NUM> or plugged from the SIM card interface <NUM>, to implement contact with or separation from the terminal <NUM>. The terminal <NUM> may support one or N SIM card interfaces, where N is a positive integer greater than <NUM>. The SIM card interface <NUM> can support a nano-SIM card, a micro-SIM card, a SIM card, and the like. A plurality of cards may be simultaneously inserted into a same SIM card interface <NUM>. The plurality of cards may be of a same type or of different types. The SIM card interface <NUM> may be compatible with different types of SIM cards. The SIM card interface <NUM> may be further compatible with an external storage card. The terminal <NUM> interacts with a network through a SIM card, to implement functions such as calling and data communication. In some embodiments, the terminal <NUM> uses an eSIM, that is, an embedded SIM card. The eSIM card may be embedded into the terminal <NUM>, and cannot be separated from the terminal <NUM>.

As shown in <FIG>, an embodiment of this application provides a Bluetooth protocol framework, including but not limited to a host (Host) protocol stack, a host controller interface (Host Controller Interface, HCI), and a controller (controller).

The host protocol stack defines a plurality of profiles (profiles) and core protocols (protocols) in a Bluetooth framework, each profile defines a corresponding message format and application rule, and the profile is a Bluetooth service (Application). To implement interconnection and interworking between different devices on different platforms, a Bluetooth protocol has formulated specifications for various possible and universal application scenarios, for example, an advanced audio distribution profile (advanced audio distribution profile, A2DP) and a hands-free profile (hands-free profile, HFP).

The core protocols include but are not limited to a basic Bluetooth service discover protocol (service discover protocol, SDP), a logical link control and adaptation protocol (logical link control and adaptation protocol, L2CAP), and the like. The core protocol is essential to a Bluetooth protocol stack.

The HCI provides a unified interface for an upper layer protocol to enter a link manager and a unified manner for entering a baseband. There are several transport layers between a host core protocol stack and the controller, and these transport layers are transparent to complete a task of transmitting data. The Bluetooth Special Interest Group (Bluetooth Special Interest Group, SIG) specifies four physical bus manners to connect to hardware, namely, four HCI transport layers: the USB, the RS232, the UART, and the PC card.

The controller defines a bottom-layer hardware part, including a radio frequency (RF), a baseband (BB), and a link manager (LM). An RF layer filters and transmits data bit streams by using microwaves on a <NUM> unlicensed ISM band, and mainly defines conditions that a Bluetooth transceiver needs to meet to work properly on this frequency band. The baseband is responsible for frequency hopping and transmission of Bluetooth data and information frames. The link manager is responsible for connection, establishment, and disconnection of links, and security control. A link manager (Link Manager, LM) layer is a link manager layer protocol of the Bluetooth protocol stack, and is responsible for translating an upper-layer HCI command into an operation acceptable to the baseband, and establishing an asynchronous connection-oriented link (asynchronous connection-oriented link, ACL), a synchronous connection-oriented (synchronous connection-oriented/extended, SCO) link, a working mode that causes the Bluetooth device to enter an energy saving state, and the like. A link control (link control, LC) layer is responsible for responding to upper-layer LM commands during transmission of a batch of data packets (for example, executing LM commands for functions such as establishing a data packet transmission link and maintaining a link).

Some content of the method described in embodiments of this application is implemented by the wireless communications module <NUM> of the terminal <NUM> shown in <FIG> may be specifically performed by a Bluetooth module or a Bluetooth chip.

<FIG> is a schematic diagram of an example of a structure of a Bluetooth device <NUM> according to an embodiment of this application.

It should be understood that the Bluetooth device <NUM> shown in <FIG> is merely an example, and the Bluetooth device <NUM> may have more or fewer components than those shown in <FIG>, may combine two or more components, or may have different component configurations. Various components shown in the figure may be implemented in hardware that includes one or more signal processing and/or application-specific integrated circuits, software, or a combination of hardware and software.

In this embodiment of this application, the Bluetooth device <NUM> may include a first earbud and a second earbud. For structures of both the first earbud and the second earbud, refer to <FIG>.

As shown in <FIG>, the Bluetooth device <NUM> may include a processor <NUM>, a memory <NUM>, a Bluetooth communications module <NUM>, an audio module <NUM>, a power module <NUM>, an input/output interface <NUM>, a sensor <NUM>, and a button <NUM>.

The processor <NUM> may be configured to read and execute computer-readable instructions. In a specific implementation, the processor <NUM> may mainly include a controller, an operator, and a register. The controller is mainly responsible for decoding an instruction, and sends a control signal for an operation corresponding to the instruction. The operator is mainly responsible for storing a register operand, an intermediate operation result, and the like that are temporarily stored during instruction execution. In a specific implementation, a hardware architecture of the processor <NUM> may be an application-specific integrated circuit (ASIC) architecture, an MIPS architecture, an ARM architecture, an NP architecture, or the like.

In some embodiments, the processor <NUM> may be configured to parse a signal received by the Bluetooth communications processing module <NUM>, for example, a pairing mode modification request sent by a terminal <NUM>. The processor <NUM> may be configured to perform a corresponding processing operation based on a parsing result, for example, generate a pairing mode modification response, and the like.

The memory <NUM> is coupled to the processor <NUM>, and is configured to store various software programs and/or a plurality of sets of instructions. In a specific implementation, the memory <NUM> may include a high-speed random access memory, and may further include a nonvolatile memory, for example, one or more magnetic disk storage devices, a flash memory device, or another nonvolatile solid-state storage device. The memory <NUM> may store an operating system, for example, an embedded operating system such as uCOS, VxWorks, or RTLinux. The memory <NUM> may further store a communication program. The communication program may be used to communicate with the terminal <NUM>, one or more servers, or another device.

The Bluetooth communications module <NUM> may include a Bluetooth chip. The Bluetooth device <NUM> may perform pairing with a Bluetooth chip of another electronic device by using the Bluetooth chip and establish a Bluetooth connection, to implement wireless communication and service processing between the Bluetooth device <NUM> and the another device through the Bluetooth connection. Generally, the Bluetooth chip may support BR/EDR Bluetooth and BLE, for example, may receive/send paging (page) information, receive/send a BLE broadcast message, and the like.

In addition, the Bluetooth communications module <NUM> may further include an antenna. The Bluetooth communications module <NUM> receives an electromagnetic wave through the antenna, performs frequency modulation and filtering processing on the electromagnetic wave signal, and sends a processed signal to the processor <NUM>. The Bluetooth communications module <NUM> may further receive a to-be-sent signal from the processor <NUM>, perform frequency modulation and amplification on the signal, and convert the signal into an electromagnetic wave through an antenna for radiation.

The audio module <NUM> may be configured to: manage audio data, and input and output an audio signal of the Bluetooth device <NUM>. For example, the audio module <NUM> may obtain an audio signal from the Bluetooth communications module <NUM>, or transmit an audio signal to the Bluetooth communications module <NUM>, to implement functions such as answering a call, playing audio, enabling/disabling a voice assistant of a terminal connected to the earbud, and receiving/sending voice data of a user through the Bluetooth device <NUM>. The audio module <NUM> may include a speaker (or referred to as an earpiece or a receiver) component configured to output an audio signal, a microphone (or referred to as a mike or a mic), a microphone radio circuit cooperating with the microphone, and the like. The speaker may be configured to: convert an audio electrical signal into a sound signal and play the sound signal. The microphone may be configured to convert a sound signal into an audio electrical signal.

The power module <NUM> may be configured to: provide system power for the Bluetooth device <NUM>, supply power to each module of the Bluetooth device <NUM>, support the Bluetooth device <NUM> in receiving a charging input, and the like. The power module <NUM> may include a power management unit (power management unit, PMU) and a battery. The power management unit may receive an external charging input, provide an electrical signal input by a charging circuit to the battery for charging, and further provide an electrical signal provided by the battery to other modules such as the audio module <NUM> and the Bluetooth communications module <NUM>, to prevent battery overcharging, over-discharging, short circuit, overcurrent, and the like. In some embodiments, the power module <NUM> may further include a wireless charging coil for wirelessly charging the Bluetooth device <NUM>. In addition, the power management unit may be further configured to monitor parameters such as a battery capacity, a battery cycle count, and a battery health status (electric leakage or impedance).

A plurality of input/output interfaces <NUM> may be configured to provide a wired connection for charging or communication between the Bluetooth device <NUM> and a charging case. In some embodiments, the input/output interface may be a USB port. In some other embodiments, the input/output interface <NUM> may be an earbud electrical connector. When the Bluetooth device <NUM> is placed into the charging case, the Bluetooth device <NUM> may charge a battery in the Bluetooth device <NUM> through an electrical connection to the charging case implemented in an earbud connector pogo pin manner. In some embodiments, after the electrical connection is established, the Bluetooth device <NUM> may further perform data communication with the charging case, for example, may receive information such as a pairing instruction, a power-on instruction, and a power-off instruction from the charging case.

In addition, the Bluetooth device <NUM> may further include a sensor <NUM>. For example, the sensor <NUM> may be a distance sensor or an optical proximity sensor, and may be configured to determine whether the Bluetooth device <NUM> is worn by a user. For example, the Bluetooth device <NUM> may detect, by using the distance sensor, whether an object exists near the Bluetooth device <NUM>, to determine whether the Bluetooth device <NUM> is worn by the user. When determining that the Bluetooth device <NUM> is worn, the Bluetooth device <NUM> may turn on a speaker.

For another example, the sensor <NUM> may further include a bone conduction sensor, to form a bone conduction headset. The Bluetooth device <NUM> may obtain a vibration signal of a vibration bone of a human vocal-cord part by using the bone conduction sensor, and obtain a voice signal through parsing, to implement a voice function, thereby receiving voice instructions of the user. The Bluetooth device <NUM> may further perform voice authentication based on the user voice signal obtained by the bone conduction headset, to authenticate a user identity in a service scenario such as a payment transaction.

For another example, the sensor <NUM> may further include: a touch sensor, configured to detect a touch operation of a user; a fingerprint sensor, configured to detect a user fingerprint, identify a user identity, and the like; an ambient light sensor, configured to adaptively adjust some parameters (such as volume) based on sensed luminance of ambient light; and some other sensors.

In some embodiments, the touch sensor may detect a touch operation of the user such as single-tap, double-tap, multi-tap, touch and hold, and heavy press, and may further perform fingerprint recognition for the user, to attempt to authenticate a user identity in a service scenario such as a payment transaction scenario.

It may be understood that, the structure illustrated in this embodiment of this application does not constitute a specific limitation on the Bluetooth device <NUM>, and the Bluetooth device <NUM> may have more or fewer components than those shown in <FIG>, may combine two or more components, or may have different component configurations. For example, an outer surface of the Bluetooth device <NUM> may further include components such as a button <NUM>, an indicator light (which may indicate a battery level, an incoming call/outgoing call, and a pairing mode), and a display (which may prompt the user with related information). The button <NUM> may be a physical button, a touch button (used in cooperation with the touch sensor), or the like, and is configured to trigger operations such as power-on, power-off, pause, play, record, start pairing, and reset.

For example, when the Bluetooth device <NUM> is a TWS headset, the Bluetooth device <NUM> may include an earbud (also referred to as a left earbud) worn on the left ear and an earbud (also referred to as a right earbud) worn on the right ear. The headset may include a housing and an inner part. The inner part is disposed in a cavity formed by the housing. The inner part may include components in modules such as the audio module, the power module, and the Bluetooth communications module shown in <FIG>.

When the Bluetooth device <NUM> is the TWS headset, the user may use the TWS headset in a binaural mode or a monaural mode. In the monaural mode, the user may wear only the left earbud or the right earbud to perform audio services such as music listening or call receiving/making. In the binaural mode, the user may wear the two earbuds to listen to music or perform another audio service. In the binaural mode, the two earbuds include a primary earbud and a secondary earbud. In addition, in a process of using the TWS headset, the primary and secondary roles of the two earbuds may be switched.

In some embodiments, the TWS headset may exchange control information, for example, connection control information or service control information, with the terminal <NUM> through the primary earbud. Therefore, a Bluetooth connection to the terminal <NUM> may be established or broken based on the connection control information, and an operation such as service action control (for example, pause, play, and last song) is performed based on the service control information.

In one case, a Bluetooth connection is established between the primary earbud and the terminal <NUM>, and Bluetooth communication may be performed between the primary earbud and the terminal <NUM> to exchange control information and audio data. A Bluetooth connection is also established between the primary earbud and the secondary earbud, and the primary earbud may notify the secondary earbud to perform status synchronization, for example, establish/break a physical connection or a virtual connection to the terminal <NUM>. The secondary earbud may receive, in a manner such as forwarding of the primary earbud and listening, audio data sent by the terminal <NUM>.

In a listening solution, the Bluetooth connection is established between the terminal <NUM> and the primary earbud, to complete sending of audio data to the primary earbud and complete a service action triggered by the terminal <NUM> and the TWS headset (for example, play, pause, switch to last song, turn up the volume). The Bluetooth connection is established between the two earbuds to complete information synchronization between the two earbuds. The secondary earbud obtains audio data by listening to a Bluetooth link between the primary earbud and the terminal <NUM>.

In a forwarding solution, the Bluetooth connection is established between the terminal <NUM> and the primary earbud to complete sending of audio data to the primary earbud and complete a service action triggered by the terminal <NUM> and the TWS headset. The Bluetooth connection is established between the two earbuds to complete information synchronization between the two earbuds, and the primary earbud forwards audio data to the secondary earbud through a Bluetooth link between the primary earbud and the secondary earbud.

<FIG> is further a schematic diagram of a charging case <NUM> used to accommodate a Bluetooth device <NUM>. In some embodiments, the charging case may include one or more magnets inside, to attract earbuds into a cavity in the charging case. The charging case may include a battery and a plurality of input/output interfaces. After an electrical connection is separately established to earbud electrical connectors in the two earbuds (an earbud <NUM> and an earbud <NUM>), the charging case <NUM> may charge a battery in the earbud by using a battery of the charging case <NUM>.

For a structure of the earbud <NUM> or the earbud <NUM> of the Bluetooth device <NUM>, refer to the schematic diagram of the structure shown in <FIG>.

In some other embodiments, at least one touch control may be disposed on the charging case, and may be configured to trigger a function such as pairing reset of the Bluetooth device <NUM> or charging a wireless earbud. The charging case may be further provided with one or more battery level indicators, to prompt the user with a battery level of the battery in the charging case and a battery level of a battery of each earbud in the charging case.

In some other embodiments, the charging case may further include components such as a processor and a memory. The memory may be configured to store application code, and the processor of the charging case controls the application code to be executed, to implement functions of the charging case. For example, the processor of the charging case executes the application program code stored in the memory to charge the Bluetooth device <NUM> when detecting that the Bluetooth device <NUM> is placed into the charging case.

In addition, a charging interface may be further disposed on the charging case, to charge the battery of the charging case. The charging case may further include a wireless charging coil, configured to wirelessly charge the battery of the charging case. It may be understood that the charging case may further include other components.

In a related technology, an example in which the Bluetooth device <NUM> is a TWS headset is used, and the Bluetooth device <NUM> has two earbuds (including a first earbud and a second earbud). When the Bluetooth device <NUM> works, the two earbuds may be classified into a primary earbud and a secondary earbud. A Bluetooth connection may be established between the primary earbud and the secondary earbud, and the primary earbud may establish a Bluetooth connection to a terminal <NUM>. The primary earbud may send connection information such as a Bluetooth address and a link key of the terminal <NUM> to the secondary earbud. In this way, the secondary earbud may also receive, by using the connection information sent by the primary earbud, data sent by the terminal <NUM> to the primary earbud. In addition, in a process of using the Bluetooth device <NUM>, primary and secondary roles of the two earbuds may be switched. When the Bluetooth device <NUM> is placed into the charging case and the charging case is closed, the Bluetooth connection established between the primary earbud in the Bluetooth device <NUM> and the terminal <NUM> is broken, and the Bluetooth connection between the primary earbud and the secondary earbud is also broken.

Currently, there is the following use scenario of a Bluetooth headset: The Bluetooth device <NUM> established a Bluetooth connection to the terminal <NUM>, and the connection information such as the Bluetooth address and the link key of the terminal <NUM> is stored on the two earbuds in the Bluetooth device <NUM>. When the Bluetooth device <NUM> is placed into the charging case, only one earbud (for example, the first earbud) is placed into the charging case. In this use scenario, when the charging case accommodating only the first earbud is opened again, the first earbud can be configured with only a single Bluetooth reconnection policy. The Bluetooth reconnection policy may be as follows:.

Reconnection policy <NUM>: As shown in <FIG>, when the first earbud detects that the charging case accommodating a single earbud is opened (that is, there is only the first earbud in the charging case), the first earbud may first send a paging request (page request) to the terminal <NUM>, to attempt to reconnect to the terminal <NUM>. In this case, if the terminal <NUM> is not around the first earbud or a Bluetooth function has been disabled and a user has connected the second earbud to another device through Bluetooth, the user needs to use the first earbud as a secondary earbud and connect to the second earbud used as a primary earbud, to receive audio data of the another device by using the first earbud and the second earbud.

However, because the terminal <NUM> is not around the first earbud or the Bluetooth function has been disabled, the terminal <NUM> cannot receive the paging request of the first earbud. Consequently, the first earbud cannot reconnect to the terminal <NUM>. The first earbud sends the paging request to the second earbud only after reconnecting to the terminal <NUM> expires (where for example, the terminal <NUM> is not reconnected to through Bluetooth for more than <NUM>), to attempt to reconnect to the second earbud. After receiving the paging request of the first earbud, the second earbud may return a paging response (page response) to the first earbud, and further establish a Bluetooth connection to the first earbud.

According to the foregoing reconnection policy <NUM>, when the charging case accommodating only the first earbud is opened, it takes a long time for the first earbud to reconnect to the second earbud based on a requirement of the user, affecting user experience.

Reconnection policy <NUM>: As shown in <FIG>, when the first earbud detects that the charging case accommodating a single earbud is opened (that is, there is only the first earbud in the charging case), the first earbud may first send a paging request (page request) to the second earbud, to attempt to reconnect to the second earbud. If the second earbud is lost and is not around the first earbud, the user can only connect the first earbud to the terminal <NUM> separately for use.

However, because the second earbud is not around the first earbud or the second earbud is lost, the first earbud cannot reconnect to the second earbud. Therefore, the first earbud needs to send the paging request to the terminal <NUM> only after reconnecting to the second earbud expires (where for example, the terminal <NUM> is not reconnected to through Bluetooth for more than <NUM>), to attempt to reconnect to the terminal <NUM>. After receiving the paging request of the first earbud, the terminal <NUM> may return a paging response to the first earbud, and further establish a Bluetooth connection to the first earbud.

According to the foregoing reconnection policy <NUM>, when the charging case accommodating only the first earbud is opened, it takes a long time for the first earbud to reconnect to the terminal <NUM> based on a requirement of the user, affecting user experience.

Therefore, an embodiment of this application provides a Bluetooth reconnection method. When a charging case accommodating only a first earbud is opened, the first earbud may determine whether a Bluetooth connection is established to a second earbud when the first earbud is placed into the charging case and the charging case is closed. If the Bluetooth connection is established to the second earbud, the first earbud preferentially reconnects to the second earbud when the charging case is opened. If the Bluetooth connection is not established to the second earbud, the first earbud preferentially reconnects to the terminal <NUM>. In this way, reconnection duration can be reduced, and user experience is improved.

The following describes a Bluetooth reconnection method provided in an embodiment of this application.

<FIG> is a schematic flowchart of a Bluetooth reconnection method according to an embodiment of this application. In this embodiment of this application, a Bluetooth device <NUM> may include a first earbud and a second earbud.

S501: A terminal <NUM> establishes a Bluetooth connection to the Bluetooth device <NUM>.

The Bluetooth device <NUM> includes the first earbud and the second earbud. The first earbud and the second earbud may play primary and secondary roles.

When the terminal <NUM> establishes the Bluetooth connection to the Bluetooth device <NUM>, there may be the following two cases.

When the first earbud is a primary earbud and the second earbud is a secondary earbud, the first earbud may first establish a Bluetooth connection to the second earbud, and then, the first earbud establishes a Bluetooth connection to the terminal <NUM>. The Bluetooth connection includes a BR/EDR Bluetooth connection. After the first earbud establishes the Bluetooth connection to the terminal <NUM> and establishes the Bluetooth connection to the second earbud, the first earbud may store a Bluetooth address (BD_ADDR) of the terminal <NUM>, and the first earbud may send the Bluetooth address of the terminal <NUM> to the second earbud.

When the first earbud is a secondary earbud and the second earbud is a primary earbud, the first earbud may first establish a Bluetooth connection to the second earbud, and then, the second earbud establishes a Bluetooth connection to the terminal <NUM>. After the second earbud establishes the Bluetooth connection to the terminal <NUM>, the second earbud may store a Bluetooth address of the terminal <NUM>, and the second earbud may send the Bluetooth address of the terminal <NUM> to the first earbud.

S502: A charging case receives a case-closed operation of a user.

A physical switch may be disposed on the charging case, and the physical switch may be used to detect whether the charging case is in a closed state. When the user closes the charging case, the physical switch on the charging case is triggered to switch to the closed state. The charging case may detect, through the physical switch, the case-closed operation of the user.

In this embodiment of this application, the charging case may detect the case-closed operation of the user through, but not limited to, the physical switch, and may alternatively detect the case-closed operation of the user through some sensors (such as a magnetic sensor or a proximity sensor). This is not limited herein.

S503: In response to the case-closed operation, the charging case sends a case-closed request to the first earbud.

When the first earbud is placed into the charging case, there is an electrical connection between the first earbud and the charging case. The charging case may send the case-closed request to the first earbud through the electrical connection.

S504: After receiving the case-closed request, the first earbud breaks the Bluetooth connection.

When the first earbud is the primary earbud, and has established the Bluetooth connection to the terminal <NUM> and has also established the Bluetooth connection to the second earbud, after receiving the case-closed request sent by the charging case, the first earbud may break the Bluetooth connection to the terminal <NUM> and the Bluetooth connection to the second earbud.

When the first earbud is the secondary earbud, and has established the Bluetooth connection to the second earbud, after receiving the case-closed request sent by the charging case, the first earbud may break the Bluetooth connection to the second earbud.

S505: The charging case receives a case-opened operation of the user.

The physical switch may be disposed on the charging case, and the physical switch may be used to detect whether the charging case is in an opened state. When the user opens the charging case, the physical switch on the charging case is triggered to switch to the opened state. The charging case may detect, through the physical switch, the case-opened operation of the user.

In this embodiment of this application, the charging case may detect the case-opened operation of the user through, but not limited to, the physical switch, and may alternatively detect the case-opened operation of the user through some sensors (such as a magnetic sensor or a proximity sensor). This is not limited herein.

S506: In response to the case-opened operation, the charging case sends a case-opened request to the first earbud.

The case-opened request may include a quantity of earbuds in the charging case.

S507: After receiving the case-opened request, the first earbud determines whether there is only the first earbud in the charging case.

After the first earbud receives the case-opened request sent by the charging case, the first earbud may determine, based on the case-opened request, whether there is only the first earbud in the charging case.

In a possible case, if there are both the first earbud and the second earbud in the charging case, the first earbud may determine whether the first earbud was paired with the second earbud. If the first earbud was paired with the second earbud, the first earbud and the second earbud preferentially perform Bluetooth reconnection. If the first earbud was not paired with the second earbud, the first earbud sends a paging request to the terminal <NUM>.

There may be the following two implementations in which the first earbud and the second earbud perform Bluetooth reconnection.

Implementation <NUM>: When the first earbud determines that the charging case includes both the first earbud and the second earbud that have been paired, the first earbud may enter a paging (page) state, and the second earbud may enter a paging scan (page scan) state. After entering the page state, the first earbud may send a paging request (page request) to the second earbud. The paging request sent by the first earbud to the second earbud includes a device access code (device access code, DAC) of the second earbud.

After the second earbud enters the page scan state, the second earbud may select, based on a paging hopping sequence (paging hopping sequence), a new monitoring frequency to monitor the device access code of the second earbud at a specific time interval (for example, <NUM>). The paging hopping sequence used by the second earbud is a well-defined periodic sequence, and various frequencies of the paging hopping sequence are evenly distributed on <NUM> frequency channels of <NUM>. Duration of scanning performed by the second earbud on a paging frequency channel may be referred to as a paging scan window (page scan windows), and a size of the paging scan window is fixed. An interval between start time points of two consecutive paging scan windows may be referred to as a paging scan interval (page scan interval), and the paging scan interval is fixed. A value range of the paging scan interval may be <NUM> to <NUM>. The second earbud monitors a device access code of the first earbud in a time period in which a scan window exists.

After receiving the paging request of the first earbud, the second earbud may send a paging response (page response) to the first earbud in a next slot. After receiving the paging response sent by the second earbud, the first earbud may initiate a connection request to the second earbud, and the first earbud and the second earbud recover the Bluetooth connection. In a connected state, the communication parties: the first earbud and the second earbud hop one frequency channel at a specific time interval (for example, <NUM> microseconds).

Implementation <NUM>: When the first earbud determines that the charging case includes both the first earbud and the second earbud that have been paired, the first earbud may enter a page scan state, and the second earbud may enter a page state. After entering the page state, the second earbud may send a paging request to the first earbud. The paging request sent by the second earbud to the first earbud includes a device access code of the first earbud.

After the first earbud enters the page scan state, the first earbud may select, based on a paging hopping sequence, a new monitoring frequency to monitor the device access code of the first earbud at a specific time interval (for example, <NUM>). The paging hopping sequence used by the first earbud is a well-defined periodic sequence, and various frequencies of the paging hopping sequence are evenly distributed on <NUM> frequency channels of <NUM>. Duration of scanning performed by the first earbud on a paging frequency channel may be referred to as a paging scan window (page scan windows), and a size of the paging scan window is fixed. An interval between start time points of two consecutive paging scan windows may be referred to as a paging scan interval (page scan interval), and the paging scan interval is fixed. A value range of the paging scan interval may be <NUM> to <NUM>. The first earbud monitors the paging request of the second earbud in a time period in which a scan window exists.

After receiving the paging request of the second earbud, the first earbud may send a paging response (page response) to the second earbud in a next slot. After receiving the paging response sent by the first earbud, the second earbud may send a connection request to the first earbud, and the first earbud and the second earbud recover the Bluetooth connection. In a connected state, the communication parties: the first earbud and the second earbud hop one frequency channel at a specific time interval (for example, <NUM> microseconds).

In some embodiments, after the first earbud and the second earbud perform Bluetooth reconnection, a primary earbud (for example, the first earbud) in the two earbuds may send a paging request to the terminal <NUM>. If the terminal <NUM> receives the paging request sent by the primary earbud, the terminal <NUM> may send a paging response to the primary earbud. After receiving the paging response sent by the terminal <NUM>, the primary earbud may send a connection request to the terminal <NUM>. Then, the Bluetooth connection between the primary earbud and the terminal <NUM> is recovered. In a state in which the primary earbud and the terminal <NUM> are connected, the primary earbud and the second earbud hop one frequency channel at a specific time interval (for example, <NUM> microseconds).

S508: If there is only the first earbud in the charging case, the first earbud may determine whether a Bluetooth connection to the second earbud is not established when the charging case is closed. If the Bluetooth connection to the second earbud is not established, step S509 is performed. The first earbud sends the paging request to the terminal <NUM>. If the Bluetooth connection to the second earbud is established, step S510 is performed. The first earbud sends the paging request to the second earbud.

In this embodiment of this application, the paging request sent by the first earbud to the second earbud may be referred to as a first paging request. The paging request sent by the first earbud to the terminal may be referred to as a second paging request.

When the charging case is closed, there are the following cases of a Bluetooth connection status of the first earbud.

Both the first earbud and the second earbud work, and the first earphone is the primary earbud. The first earbud has established the Bluetooth connection to the terminal <NUM>. The first earbud has established the Bluetooth connection to the second earbud.

Both the first earbud and the second earbud work, and the first earphone is the secondary earbud. The first earbud has established the Bluetooth connection to the second earbud. The second earbud is the primary earbud, and the second earbud has established the Bluetooth connection to the terminal <NUM>.

Only the first earbud works, and the first earbud has established the Bluetooth connection to the terminal <NUM>.

When the first earbud determines that there is only the first earbud in the charging case, the first earbud may determine, based on historical connection information, whether a Bluetooth connection is established to the second earbud when the charging case is closed.

If the first earbud determines that the Bluetooth connection is established to the second earbud when the charging case is closed, the first earbud may enter the page state when the charging case is opened, and send the paging request to the second earbud based on a Bluetooth address of the second earbud. If receiving the paging request sent by the first earbud, the second earbud may send a slave device paging response (page response) to the first earbud in the next slot. After receiving the paging response sent by the second earbud, the first earbud may initiate the connection request to the second earbud, and the two earbuds may recover the Bluetooth connection. In a connected state, the communication parties: the first earbud and the second earbud hop one frequency channel at a specific time interval (for example, <NUM> microseconds).

In a possible implementation, when the second earbud is not around the first earbud or has no power, the second earbud cannot receive the paging request sent by the first earbud, and does not return a slave device paging response to the first earbud. If the first earbud cannot receive, within preset time (for example, <NUM>), the slave device paging response returned by the second earbud, the first earbud may stop sending the paging request to the second earbud, and send the paging request to the terminal <NUM> based on the Bluetooth address of the terminal <NUM>. After receiving the paging request sent by the first earbud, the terminal <NUM> may return the paging response to the first earbud. After receiving the paging response sent by the terminal <NUM>, the first earbud may initiate a connection to the terminal <NUM>, and the first earbud and the terminal <NUM> may enter a connected state. In the connected state, the communication parties: the first earbud and the terminal <NUM> hop one frequency channel at a specific time interval (for example, <NUM> microseconds). In this case, the Bluetooth connection between the first earbud and the terminal <NUM> is recovered.

If determining that the first earbud does not establish the Bluetooth connection to the second earbud and establishes the Bluetooth connection to only the terminal <NUM> when the charging case is closed, the first earbud may enter the page state, and send the paging request to the terminal <NUM> based on the Bluetooth address of the terminal <NUM>. After receiving the paging request sent by the first earbud, the terminal <NUM> may send the paging response to the first earbud in the next slot. After receiving the paging response sent by the terminal <NUM>, the first earbud may initiate a connection to the terminal <NUM>, and the first earbud and the terminal <NUM> may enter a connected state. In the connected state, the communication parties: the first earbud and the terminal <NUM> hop one frequency channel at a specific time interval (for example, <NUM> microseconds). In this case, the Bluetooth connection between the first earbud and the terminal <NUM> is recovered.

In a possible implementation, when the terminal <NUM> is not around the first earbud or has disabled a Bluetooth function, the terminal <NUM> cannot receive the paging request sent by the first earbud, and does not return the paging response to the first earbud. If the first earbud cannot receive, within preset time (for example, <NUM>), the paging response returned by the terminal <NUM>, the first earbud may stop sending the paging request to the terminal <NUM>, and send the paging request to the second earbud based on the Bluetooth address of the second earbud. After receiving the paging request sent by the first earbud, the second earbud may return the paging response to the first earbud. After receiving the paging response sent by the second earbud, the first earbud may initiate a connection to the second earbud, and the first earbud and the second earbud may enter a connected state. In the connected state, the communication parties: the first earbud and the second earbud hop one frequency channel at a specific time interval (for example, <NUM> microseconds). In this case, the Bluetooth connection between the first earbud and the second earbud is recovered.

In this embodiment of this application, when the charging case is opened, after the first earbud sends the paging request to the second earbud (where the paging request sent to the second earbud may be referred to as the first paging request), if the first earbud does not receive, within first preset time (for example, <NUM> seconds), the paging response sent by the second earbud (where the paging response returned by the second earbud may be referred to as a first paging response), the first earbud may switch to sending the paging request to the terminal (where the paging request sent to the terminal may be referred to as the second paging request). In this way, the first earbud can switch to reconnecting to the terminal in a timely manner when reconnecting to the second earbud expires.

When the charging case is opened, the first earbud sends the paging request to the terminal. If the first earbud does not receive, within second preset time (for example, <NUM> seconds), the paging response (where the paging response returned by the terminal may be referred to as a second paging response) sent by the terminal, the first earbud may switch to sending the paging request to the second earbud. In this way, the first earbud can switch to reconnecting to the second earbud in a timely manner when reconnecting to the terminal expires.

According to the Bluetooth reconnection method provided in this embodiment of this application, when the charging case accommodating only the first earbud is opened, the first earbud may determine whether the first earbud establishes the Bluetooth connection to only the second earbud or establishes the Bluetooth connections to both the second earbud and the terminal <NUM> when the first earbud is placed into the charging case and the charging case is closed. If the first earbud establishes the Bluetooth connection to only the second earbud or establishes the Bluetooth connections to both the second earbud and the terminal <NUM> when the charging case is closed, the first earbud preferentially reconnects to the second earbud. If the first earbud establishes the Bluetooth connection to only the terminal <NUM> when the charging case is closed, the first earbud preferentially reconnects to the terminal <NUM>. In this way, reconnection duration can be reduced, and user experience is improved.

In some application scenarios, the Bluetooth device <NUM> includes the first earbud and the second earbud. When the Bluetooth device <NUM> establishes the Bluetooth connection to the terminal <NUM>, the user may set the Bluetooth device <NUM> to a monaural working mode on the terminal <NUM>. When the Bluetooth device <NUM> is in the monaural working mode, the terminal <NUM> may establish a Bluetooth connection to only one earbud (for example, the first earbud) of the Bluetooth device <NUM>. When the charging case accommodating only the first earbud is opened, the first earbud may determine whether a working mode is the monaural working mode. If the working mode is the monaural working mode, the first earbud may preferentially reconnect to the terminal <NUM> when the charging case is opened. In this way, when the charging case accommodating only one earbud is opened, the earbud in the charging case can quickly reconnect to the terminal <NUM> through Bluetooth, to improve user experience.

<FIG> is a schematic flowchart of a Bluetooth reconnection method according to another embodiment of this application. In this embodiment of this application, the Bluetooth device <NUM> may include a first earbud and a second earbud. The first earbud may be placed into a charging case, and the second earbud is outside the charging case.

S601: The first earbud establishes a Bluetooth connection to the second earbud.

S602: The first earbud establishes a Bluetooth connection to a terminal <NUM>.

When the first earbud is a primary earbud and the second earbud is a secondary earbud, the first earbud may first establish the Bluetooth connection to the second earbud, and then, the first earbud establishes the Bluetooth connection to the terminal <NUM>. The Bluetooth connection includes a BR/EDR Bluetooth connection. After the first earbud establishes the Bluetooth connection to the terminal <NUM> and establishes the Bluetooth connection to the second earbud, the first earbud may store a Bluetooth address (BD_ADDR) of the terminal <NUM>, and the first earbud may send the Bluetooth address of the terminal <NUM> to the second earbud.

S603: The terminal <NUM> receives an operation of setting a monaural mode by a user.

S604: In response to the operation of setting the monaural mode, the terminal <NUM> sends a monaural mode switching request to the first earbud.

For example, as shown in <FIG>, the terminal <NUM> displays an interface <NUM> of a home screen. The interface <NUM> displays a page on which application icons are placed, and the page includes a plurality of application icons (for example, a Weather icon, a Stock icon, a Calculator icon, a Settings icon <NUM>, an Email icon, an Alipay icon, a Facebook icon, a Browser icon, a Gallery icon, a Music icon, a Videos icon, and an App store icon). A page indicator is further displayed below a plurality of application icons, to indicate a position relationship between a currently displayed page and another page. A plurality of tray icons (for example, a Phone icon, a Messages icon, a Contacts icon, and a Camera icon) are below the page indicator. The tray icons remain displayed when the page is switched, and the page may include a plurality of application icons and page indicators. Alternatively, the page indicator may not be a part of the page and may exist independently, and the tray icon is also optional. This is not limited in this embodiment of this application. A status bar <NUM> is displayed above the interface <NUM>. The status bar <NUM> may include one or more signal strength indicators of a mobile communication signal (which may be also referred to as a cellular signal), one or more signal strength indicators of a wireless fidelity (wireless fidelity, Wi-Fi) signal, a battery status indicator, a time indicator, and the like. A navigation bar <NUM> is displayed below the tray icons. The navigation bar <NUM> may include system navigation buttons such as a return button <NUM>, a home screen (Home screen) button <NUM>, and an outgoing call task history button <NUM>. When it is detected that the user clicks the return button <NUM>, the terminal <NUM> may display a previous page of a current page. When it is detected that the user clicks the home screen button <NUM>, the terminal <NUM> may display the home screen. When it is detected that the user clicks the outgoing call task history button <NUM>, the terminal <NUM> may display a task that the user has recently opened. Names of the navigation buttons may alternatively be other names. This is not limited in this application. In addition to a virtual button, each navigation button in the navigation bar <NUM> may be further implemented as a physical button.

The terminal <NUM> may receive an input operation (for example, click) of the user for the setting icon <NUM>, and in response to the input operation for the setting icon <NUM>, the terminal <NUM> may display a setting interface <NUM> shown in <FIG>.

As shown in <FIG>, the setting interface <NUM> displays a wireless and network setting entry, a device connection setting entry <NUM>, an application and notification setting entry, a battery setting entry, a display setting entry, a sound setting entry, a storage setting entry, a security and privacy setting entry, a user and account setting entry, and the like.

The terminal <NUM> may receive an input operation (for example, click) of the user for the device connection entry <NUM>, and in response to the input operation for the device connection entry <NUM>, the terminal <NUM> may display a device connection interface <NUM> shown in <FIG>.

As shown in <FIG>, the device connection interface <NUM> displays a Bluetooth setting entry <NUM>, an NFC setting entry, a Huawei Beam setting entry, a Huawei Share setting entry, a mobile phone projection setting entry, a USB setting entry, a print setting entry, and the like.

The terminal <NUM> may receive an input operation of the user for the Bluetooth setting entry <NUM> on the device connection interface <NUM>, and in response to the input operation for the Bluetooth setting entry <NUM>, the terminal <NUM> may display the Bluetooth setting interface <NUM> shown in <FIG>.

As shown in <FIG>, the Bluetooth setting interface <NUM> displays a Bluetooth switch entry <NUM>, a device name setting entry <NUM>, a received file setting entry <NUM>, a scanning control, and a help control. The Bluetooth switch entry <NUM> displays a Bluetooth switch <NUM>. The Bluetooth switch <NUM> may be used to receive an operation of the user, and trigger the terminal <NUM> to enable/disable a Bluetooth function. When the Bluetooth switch <NUM> is turned on, the terminal <NUM> may display a paired device list <NUM> and an available device list <NUM> on the Bluetooth setting interface <NUM>. One or more paired device options may be displayed in the paired list <NUM> (for example, "HUAWEI Free Buds" device option <NUM> and "HUAWEI AM08" device option). The terminal <NUM> has established a connection to the Bluetooth device <NUM>, and the Bluetooth device <NUM> corresponds to the device option <NUM>. A device name of the Bluetooth device may be "HUAWEI Free Buds". A device setting control <NUM> may be provided on the device option <NUM> corresponding to the Bluetooth device <NUM>.

The terminal <NUM> may receive an input operation (for example, click) of the user for the device setting control <NUM>, and in response to the operation, the terminal <NUM> may display a device setting interface <NUM> shown in <FIG>.

As shown in <FIG>, the setting interface <NUM> of the device setting interface <NUM> includes setting options such as a renaming setting option, a call audio setting option, a media audio setting option, and a monaural mode setting option <NUM>. A switch <NUM> is provided on the monaural mode setting option <NUM>. The switch <NUM> may be used to trigger the Bluetooth device <NUM> to enter a monaural working mode.

The terminal <NUM> may receive an opening operation (for example, click) of the user for the switch <NUM>, and in response to the opening operation, the terminal <NUM> sends a monaural mode switching request to the Bluetooth device <NUM>, to request the Bluetooth device <NUM> to enter the monaural mode.

As shown in <FIG>, after the terminal <NUM> receives the opening operation of the user for the switch <NUM>, the switch <NUM> for the monaural mode may be in an open state.

The first earbud in the Bluetooth device <NUM> serves as the primary earbud and establishes the Bluetooth connection to the terminal <NUM>. Therefore, the monaural mode switching request sent by the terminal <NUM> to the Bluetooth device <NUM> may be specifically that the terminal <NUM> sends the monaural mode switching request to the first earbud.

S605: The first earbud disconnects from the second earbud after receiving the monaural mode switching request.

After receiving the monaural mode switching request of the terminal <NUM>, the first earbud enters the monaural mode, and notifies the second earbud to enter the monaural mode. Then, the first earbud breaks the Bluetooth connection to the second earbud.

In some embodiments, the first earbud is the secondary earbud, the second earbud is the primary earbud, the second earbud establishes the Bluetooth connection to the terminal <NUM>, and the first earbud establishes the Bluetooth connection to the second earbud. After receiving the operation of setting the monaural mode by the user, the terminal <NUM> may send the monaural mode switching request to the second earbud. After receiving the monaural mode switching request sent by the terminal <NUM>, the second earbud may first switch to the monaural mode, and notify the first earbud to switch to the monaural mode. Then, the second earbud disconnects from the first earbud. Because both the first earbud and the second earbud have entered the monaural mode, when Bluetooth reconnection is performed, both the first earbud and the second earbud select to send the paging request to the terminal <NUM>.

S606: The charging case receives a case-closed operation of the user.

When only the first earbud is placed into the charging case, the charging case may receive the case-closed operation of the user. A physical switch may be disposed on the charging case, and the physical switch may be used to detect whether the charging case is in a closed state. When the user closes the charging case, the physical switch on the charging case is triggered to switch to the closed state. The charging case may detect, through the physical switch, the case-closed operation of the user. In this embodiment of this application, the charging case may detect the case-closed operation of the user through, but not limited to, the physical switch, and may alternatively detect the case-closed operation of the user through some sensors (such as a magnetic sensor or a proximity sensor). This is not limited herein.

S607: The charging case sends a case-closed request to the first earbud.

S608: The first earbud breaks the Bluetooth connection to the terminal <NUM>.

After receiving the case-closed request sent by the charging case, the first earbud may send a disconnection request to the terminal <NUM>, to break the Bluetooth connection to the terminal <NUM>.

S609: The charging case receives a case-opened operation of the user.

The physical switch may be disposed on the charging case, and the physical switch may be used to detect whether the charging case is in an opened state. When the user opens the charging case, the physical switch on the charging case is triggered to switch to the opened state. The charging case may detect, through the physical switch, the case-opened operation of the user. In this embodiment of this application, the charging case may detect the case-opened operation of the user through, but not limited to, the physical switch, and may alternatively detect the case-opened operation of the user through some sensors (such as a magnetic sensor or a proximity sensor). This is not limited herein.

S610: The charging case sends a case-opened request to the first earbud.

When the first earbud is placed into the charging case, there is the electrical connection between the first earbud and the charging case. The charging case may send the case-opened request to the first earbud through the electrical connection.

S611: After receiving the case-opened request sent by the terminal <NUM>, the first earbud may determine whether the first earbud is currently in the monaural mode. If the first earbud is currently in the monaural mode, S612 in which the first earbud sends the paging request to the terminal <NUM> is performed. If the first earbud is not in the monaural mode, the first earbud may send the paging request to the second earbud.

Before the first earbud is placed into the charging case, the user has set the two earbuds of the Bluetooth device <NUM> to the monaural working mode on the terminal <NUM>. Therefore, when the first earbud detects that the charging case is opened, the first earbud may send the paging request to the terminal <NUM>.

S613: After receiving the paging request sent by the first earbud, the terminal <NUM> may determine whether the terminal <NUM> is currently connected to the second earbud. If the terminal <NUM> is not currently connected to the second earbud, step S614 in which the terminal <NUM> may send a paging response to the first earbud is performed. If the terminal <NUM> is currently connected to the second earbud, step S615 in which the terminal <NUM> may send a rejection response to the first earbud is performed.

In a possible case, when the charging case is closed, after the first earbud breaks the Bluetooth connection to the terminal <NUM>, because the second earbud has also entered the monaural mode and normally works outside the charging case, the second earbud may enter a page state, and send the paging request to the terminal <NUM> based on the Bluetooth address of the terminal <NUM>. If receiving the paging request sent by the second earbud, the terminal <NUM> may send a paging response (page response) to the second earbud in a next slot. After receiving the paging response sent by the terminal <NUM>, the second earbud may initiate a connection to the terminal <NUM>, and the second earbud and the terminal <NUM> may enter a connected state. In the connected state, the communication parties: the second earbud and the terminal <NUM> hop one frequency channel at a specific time interval (for example, <NUM> microseconds). In this case, the Bluetooth connection between the second earbud and the terminal <NUM> is recovered. In this case, the second earbud has established the Bluetooth connection to the terminal <NUM>, and the second earbud works in the monaural mode. The second earbud rejects the paging request of the first earbud, and the terminal <NUM> cannot establish the Bluetooth connection to the first earbud.

When the terminal <NUM> receives the paging request sent by the first earbud, the terminal <NUM> may determine whether the Bluetooth connection to the second earbud is currently established. If the terminal <NUM> does not currently establish the Bluetooth connection to the second earbud, the terminal <NUM> may send a paging response to the first earbud. After receiving the paging response of the terminal <NUM>, the first earbud may initiate a connection to the terminal <NUM>, and the first earbud and the terminal <NUM> may enter a connected state. In the connected state, the communication parties: the first earbud and the terminal <NUM> hop one frequency channel at a specific time interval (for example, <NUM> microseconds). In this case, the Bluetooth connection between the first earbud and the terminal <NUM> is recovered.

Claim 1:
A Bluetooth paging method, wherein the method is applied to a Bluetooth system (<NUM>), the Bluetooth system comprises a terminal (<NUM>), a first earbud (<NUM>), a second earbud (<NUM>), and a charging case (<NUM>), the charging case (<NUM>) is configured to accommodate the first earbud (<NUM>) and the second earbud (<NUM>), and the method comprises:
establishing, by the first earbud (<NUM>), a first Bluetooth connection with the terminal (<NUM>);
the first earbud (<NUM>) is placed into the charging case (<NUM>), and the charging case (<NUM>) is closed, wherein a second Bluetooth connection between the first earbud (<NUM>) and the second earbud (<NUM>) is not established when the charging case (<NUM>) is closed;
when the charging case (<NUM>) is opened and the charging case (<NUM>) accommodates only the first earbud (<NUM>), sending, by the first earbud (<NUM>), a first paging request to the terminal (<NUM>)