Patent Description:
With rapid development of mobile communications technologies, portable devices such as mobile phones and tablet computers have become necessities in people's daily life, and a Bluetooth technology has become a standard configuration for these portable devices.

Listening to Bluetooth music based on a Bluetooth technology is one of the most valuable applications of Bluetooth. The advanced audio distribution profile (A2DP) is used for an application to implement a function of playing the Bluetooth music. Based on a conventional Bluetooth technology, audio data is transmitted by using an asynchronous connection-oriented logical transport (ACL) connection between devices, and currently, a Bluetooth device can provide a maximum physical rate of <NUM> megabits per second (Mb/s).

However, limited by a physical rate in a current Bluetooth specification, Bluetooth audio is transmitted in a lossy compression mode with a relatively high compression ratio, and transmission of higher-definition audio data cannot be supported.

<CIT> discloses an radio transmitting apparatus includes a first initial phase value setting circuit that sets, in the first modulator, an initial value of the phase of the first modulated signal, which is a value at the start of the modulation according to the first modulation scheme.

<CIT> provides a terminal adapted to transmit audio data via Bluetooth to a device.

Embodiments of this application provide an audio data transmission method and apparatus, to increase an audio bit rate, thereby supporting transmission of higher-definition audio data.

According to a first aspect, an embodiment of this application provides an audio data transmission method. The method includes:
encapsulating, based on a physical layer frame header, a protocol data unit PDU including audio data, to obtain an audio data packet, where the physical layer frame header is modulated by using a first digital modulation scheme, the PDU is modulated by using a second digital modulation scheme, a value of a symbol rate of the first digital modulation scheme is equal to a value of a bit rate of the first digital modulation scheme, and a value of a symbol rate of the second digital modulation scheme is less than the value of the bit rate of the second digital modulation scheme; and sending the audio data packet on a Bluetooth low energy BLE physical channel at the bit rate of the second digital modulation scheme, wherein a bandwidth of the BLE physical channel is <NUM> or <NUM>.

In the foregoing method, the physical layer frame header is modulated by using the first digital modulation scheme, and the PDU is modulated by using the second digital modulation scheme. Because the physical layer frame header and the PDU are modulated by using two different modulation schemes, the symbol rate of the modulation scheme for the PDU is lower than the bit rate of the second digital modulation scheme, that is, a same symbol can carry more bits, thereby increasing an audio data transmission rate. Therefore, transmission of high-definition audio data can be supported.

In a possible design, the method further includes: generating a modulation scheme identifier of the BLE physical channel; based on the modulation scheme identifier, determining that the physical layer frame header uses the first digital modulation scheme, and determining that the PDU uses the second digital modulation scheme; and sending the modulation scheme identifier.

In the foregoing method, the modulation scheme used by the physical layer frame header and the modulation scheme used by the PDU can be determined based on the modulation scheme identifier. In this way, a receiving device can demodulate the PDU based on the determined modulation scheme. In a possible design, the bit rate of the second digital modulation scheme is N times the symbol rate of the second digital modulation scheme, where N is an integer greater than <NUM>.

In the foregoing method, high-definition audio data can be transmitted on the BLE physical channel at the bit rate based on the PDU that is modulated by using the second digital modulation scheme.

In a possible design, the PDU includes a control layer frame header and a payload payload; the payload is used to carry the audio data; and the control layer frame header includes indication information used to indicate a length of the audio data.

In the foregoing method, the receiving device can verify, based on the indication information for the length of the audio data in the control layer frame header, whether the received audio data is complete.

In a possible design, when a bandwidth of the BLE physical channel is <NUM>, and the physical channel having the bandwidth of <NUM> is formed by combining two adjacent physical channels each having a bandwidth of <NUM>.

In the foregoing method, the audio data can be transmitted at different bit rates by using bandwidths of different physical channels.

In a possible design, the first digital modulation scheme includes Gaussian frequency-shift keying GFSK, and the second digital modulation scheme includes differential quadrature phase shift keying DQPSK or <NUM>-differential phase shift keying 8DPSK.

In the foregoing method, the first digital modulation scheme is the GFSK, and the second digital modulation scheme is the DQPSK or the 8DPSK. In this way, compatibility between a BLE mode and an EDR mode is implemented, and power consumption can be reduced while the audio data is transmitted at a high speed.

In a possible design, a modulation factor of the GFSK ranges from <NUM> to <NUM>.

In the foregoing method, the modulation factor of the GFSK falls within the range from <NUM> to <NUM>, so that an original hardware device can be used, thereby saving hardware resources.

In a possible design, the method further includes: querying a codec codec parameter by using the logical link control and adaptation protocol L2CAP, where the codec parameter includes a coding parameter of the audio data; and encoding original audio data based on the coding parameter, to obtain the audio data.

In the foregoing method, the coding parameter is queried by using the L2CAP, and the original audio data is encoded, to ensure normal audio play.

According to a second aspect, an embodiment of this application provides an audio data transmission method. The method includes: receiving an audio data packet on a Bluetooth low energy BLE physical channel, where the audio data packet includes a physical layer frame header and a protocol data unit PDU; and demodulating the physical layer frame header by using a first digital modulation scheme, and demodulating the PDU by using a second digital modulation scheme, to obtain audio data, where a value of a symbol rate of the first digital modulation scheme is equal to a value of a bit rate of the first digital modulation scheme, and a value of a symbol rate of the second digital modulation scheme is less than the value of the bit rate of the second digital modulation scheme; wherein a bandwidth of the BLE physical channel is <NUM> or <NUM>, and audio data packet is transmitted at the bit rate of the second digital modulation scheme.

In the foregoing method, the audio data packet is received on the BLE physical channel, the physical layer frame header is demodulated by using the first digital modulation scheme, and the PDU is demodulated by using the second digital modulation scheme. The symbol rate of the modulation scheme for the PDU of the received audio data packet is lower than the bit rate of the second digital modulation scheme, that is, a same symbol can carry more bits, thereby increasing an audio data transmission rate, and supporting transmission of high-definition audio data.

In a possible design, the method further includes: receiving a modulation scheme identifier of the BLE physical channel; and determining, based on the modulation scheme identifier, that the physical layer frame header uses the first digital modulation scheme, and determining, based on the modulation scheme identifier, that the PDU uses the second digital modulation scheme.

In the foregoing method, the first digital modulation scheme and the second digital modulation scheme can be determined based on the modulation scheme identifier, and then the audio data can be successfully demodulated.

In a possible design, the bit rate of the second digital modulation scheme is N times the symbol rate of the second digital modulation scheme, where N is an integer greater than <NUM>.

In a possible design, after the obtaining audio data, the method further includes: returning an acknowledgement message to a sending device, where the acknowledgement message is used to indicate a receiving status of the audio data.

In the foregoing method, the acknowledgement message is returned to the sending device, to notify the sending device whether a receiving device receives the audio data.

According to a third aspect, an embodiment of this application provides an audio data transmission apparatus. The apparatus includes a baseband processor and a transmitter; the baseband processor encapsulates, based on a physical layer frame header, a protocol data unit PDU including audio data, to obtain an audio data packet, where the physical layer frame header is modulated by using a first digital modulation scheme, the PDU is modulated by using a second digital modulation scheme, a value of a symbol rate of the first digital modulation scheme is equal to a value of a bit rate of the first digital modulation scheme, and a value of a symbol rate of the second digital modulation scheme is less than the value of the bit rate of the second digital modulation scheme; and the transmitter sends the audio data packet on a Bluetooth low energy BLE physical channel at the bit rate of the second digital modulation scheme, wherein a bandwidth of the BLE physical channel is <NUM> or <NUM>.

For the foregoing apparatus, the physical layer frame header is modulated by using the first digital modulation scheme, and the PDU is modulated by using the second digital modulation scheme. Because the physical layer frame header and the PDU are modulated by using two different modulation schemes, the symbol rate of the modulation scheme for the PDU is lower than the bit rate of the second digital modulation scheme, that is, a same symbol can carry more bits, thereby increasing an audio data transmission rate. Therefore, transmission of high-definition audio data can be supported.

In a possible design, the apparatus further includes an audio codec codec, configured to generate a modulation scheme identifier of the BLE physical channel; the baseband processor is configured to: based on the modulation scheme identifier, determine that the physical layer frame header uses the first digital modulation scheme, and determine that the PDU uses the second digital modulation scheme; and the transmitter is configured to send the modulation scheme identifier.

According to a fourth aspect, an embodiment of this application provides an audio data transmission apparatus. The apparatus includes a receiver and a baseband processing module; the receiver is configured to receive an audio data packet on a Bluetooth low energy BLE physical channel, where the audio data packet includes a physical layer frame header and a protocol data unit PDU; and the baseband processing module is configured to: demodulate the physical layer frame header by using a first digital modulation scheme, and demodulate the PDU by using a second digital modulation scheme to obtain audio data, where a value of a symbol rate of the first digital modulation scheme is equal to a value of a bit rate, and a value of a symbol rate of the second digital modulation scheme is less than the value of the bit rate; wherein a bandwidth of the BLE physical channel is <NUM> or <NUM>, and audio data packet is transmitted at the bit rate of the second digital modulation scheme.

In the foregoing apparatus, the audio data packet is received on the BLE physical channel, the physical layer frame header is demodulated by using the first digital modulation scheme, and the PDU is demodulated by using the second digital modulation scheme. The symbol rate of the modulation scheme for the PDU is lower than the bit rate, that is, a same symbol can carry more bits, thereby increasing an audio data transmission rate, and supporting transmission of high-definition audio data.

Further "embodiments" mentioned in the following description which are not covered by the appended claims are to be seen as illustrative examples for a better understanding of the invention.

<FIG> is an overall framework diagram of a typical Bluetooth system according to an embodiment of this application. As shown in the figure, the Bluetooth system includes a Bluetooth host and a Bluetooth module. The Bluetooth host exchanges data with the Bluetooth module through a host controller interface (HCL) under control of an application program and a higher layer protocol. The Bluetooth host exchanges data with another Bluetooth system by using a host controller, a link manager (LinkManager), Bluetooth audio, baseband and link control, and radio frequency in the Bluetooth module.

<FIG> is an overall schematic structural diagram of a Bluetooth system according to an embodiment of this application. The Bluetooth system includes an audio source device <NUM>, a Bluetooth controller <NUM>, an audio receiving device <NUM>, and a Bluetooth controller <NUM>. The audio source device <NUM> sends audio data to the audio receiving device <NUM> by using the Bluetooth controller <NUM> and the Bluetooth controller <NUM>.

A sending device includes the audio source device <NUM> and the Bluetooth controller <NUM>. A receiving device includes the audio receiving device <NUM> and the Bluetooth controller <NUM>. In this embodiment of this application, an example in which the sending device sends audio data to the receiving device is used for description. It should be understood that the receiving device may also send audio data to the sending device by using a same technical solution.

In an optional case, a structure of the audio source device <NUM> is the same as a structure of the audio receiving device <NUM>. The structure of the audio source device is used as an example for description below. The audio source device <NUM> includes a Bluetooth host protocol stack module <NUM>, an audio encoding module <NUM>, and a serial communication module <NUM>.

When transmitting audio data, the Bluetooth host protocol stack module <NUM> may negotiate an audio encoding related parameter with the audio receiving device <NUM> by using the audio encoding module <NUM>. Further, the Bluetooth host protocol stack module <NUM> may transmit the audio data by using the serial communication module <NUM>.

For example, the Bluetooth controller <NUM> includes a pulse code modulation module <NUM>, a serial communication module <NUM>, an ACL and audio connection management module <NUM>, a Bluetooth baseband module <NUM>, and a radio frequency module <NUM>.

The pulse code modulation module <NUM> transmits an encoder parameter to the ACL and audio connection management module <NUM>. The serial communication module <NUM> transmits the audio data to the ACL and audio connection management module <NUM>. The ACL and audio connection management module <NUM> transmits data to the Bluetooth controller <NUM> by using the Bluetooth baseband module <NUM> and the radio frequency module <NUM>.

For a structure and a function of the Bluetooth controller <NUM> of the receiving device, refer to descriptions of the Bluetooth controller <NUM>, and details are not described herein again.

An audio data transmission method provided in an embodiment of this application is described below with reference to <FIG> and <FIG>. The audio data transmission method specifically includes the following steps.

S1: Create an asynchronous connection-oriented logical transport (Asynchronous Connection-oriented logical transport, ACL) connection.

For example, the audio source device creates an ACL connection to the audio receiving device <NUM> by using the Bluetooth host protocol stack module <NUM>. The ACL connection may be a conventional Bluetooth ACL connection or a BLE ACL connection.

Further, the audio source device negotiates a codec parameter for the audio source device and the audio receiving device by using the logical link control and adaptation protocol (L2CAP) layer protocol.

S2: The ACL connection is in a low energy state.

For example, when no audio is played or audio play is temporarily stopped, the ACL connection is in the low energy state with a short duty cycle.

In an example, when no audio is played or audio play is temporarily stopped, a breathing mode is used, where the breathing mode is implemented by updating a connection parameter to set a long-interval connection mode. In the breathing mode, a quantity of slots for sending data by the sending device is reduced, and a quantity of slots listened to by the receiving device is correspondingly reduced, to save power.

S3: The sending device creates an audio connection to the receiving device.

The sending device creates the audio connection to the receiving device, for transmission of high-definition audio data.

For example, the audio data is transmitted by the audio source device <NUM> to the Bluetooth controller <NUM> through a host controller interface (HCI) or an inter-integrated circuit sound bus (I2S) interface after the audio source device <NUM> performs compression coding (lossy or lossless) on audio pulse code modulation (PCM) data at an application layer.

Referring to <FIG>, after the serial communication module <NUM> receives the audio data from the HCI interface, the serial communication module <NUM> transmits the audio data to the ACL and audio connection management module <NUM>, or after the pulse code modulation module <NUM> receives the audio data from the audio encoding module <NUM>, the pulse code modulation module <NUM> transmits the audio data to the ACL and audio connection management module <NUM>. The ACL and audio connection management module <NUM> encapsulates the audio data, to generate the PDU.

For example, the PDU includes a control layer frame header and a payload. The payload is used to carry the audio data. It should be understood that the audio data carried in the payload may include audio data obtained by encoding original audio data, and optionally, the audio data may alternatively include audio data on which encryption and integrity check are performed.

For example, <FIG> is a schematic diagram of a PDU data format according to an embodiment of this application. In an optional case, if a payload is encrypted for transmission, MIC is an integrity check bit of encrypted data; or if a payload is not encrypted for transmission, there is no MIC field.

For example, <FIG> is a schematic structural diagram of a PDU control layer frame header according to an embodiment of this application. The header includes a next sequence number (NESN) field, a sequence number (SN) field, and a more data (MD) field that are used to perform transmission with a peer device. A transmission mechanism of a BLE ACL packet is reused in this embodiment. A length of the NESN field is <NUM> bit; a length of the SN field is <NUM> bit; a length of the MD field is <NUM> bit; and a length of a reserved for future use (RFU) field is <NUM> bits. For example, the header includes indication information used to indicate a length of a payload. For example, in <FIG>, the length indication information is represented by Length, and optionally, a length of Length is <NUM> bits, and a valid value ranges from <NUM> to <NUM>.

Referring to <FIG>, the Bluetooth baseband module <NUM> encapsulates the PDU based on a time sequence parameter negotiated by the ACL and audio connection management module <NUM>. For example, the time sequence parameter includes a maximum transmission length of the PDU, a minimum transmission interval of the PDU, a maximum transmission interval of the PDU, and a connection anchor time of the PDU. The connection anchor time of the PDU is a time point after a start point location of a currently transmitted message. For example, the PDU is encapsulated based on a physical layer frame header, that is, one physical layer frame header is added before the PDU. In an optional case, the physical layer frame header is modulated by using a GFSK modulation scheme having a modulation factor ranging from <NUM> to <NUM>. The physical layer frame header may use a <NUM>/<NUM> frame header of the GFSK. For example, the encapsulated PDU may be referred to as an audio data packet. <FIG> is a schematic structural diagram of a physical frame of an audio data packet according to an embodiment of this application.

Some fields in the physical frame are described below.

<FIG> is a schematic diagram of a preamble format according to an embodiment of this application.

A time of the preamble is always <NUM> microseconds. A preamble of a high-definition <NUM> channel includes <NUM> bits, and a preamble of a high-definition <NUM> channel includes <NUM> bits. A bit format "<NUM>" or "<NUM>" is determined based on the first bit "<NUM>" or "<NUM>" of an access address.

In an example, if the first bit of the access address is <NUM>, the preamble starts with "<NUM>"; or if the first bit of the access address is <NUM>, the preamble starts with "<NUM>".

(<NUM>) Referring to <FIG>, the access address includes <NUM> bits, and a format in the Bluetooth BLE protocol is reused.

(<NUM>) Referring to <FIG>, a trailer of the GFSK includes <NUM> all-zero bits.

(<NUM>) Referring to <FIG>, a guard time is an interval calculated from the last trailer bit of the GFSK to the first bit of a DPSK synchronization word (sync word).

In an example, the guard time may be <NUM> microseconds; however, considering an actual fluctuation, the guard time is allowed to change within +/- <NUM> microsecond. Values of the guard time may all be <NUM>, or may be in a repeated form such as <NUM>.

(<NUM>) Referring to <FIG>, a sync word of a DQPSK modulation scheme is <NUM> symbols and follows an EDR DQPSK design in a Bluetooth protocol: The first symbol is any phase (reference), and bits of the last <NUM> symbols are <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, -<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

A sync word of an 8DPSK modulation scheme is <NUM> symbols and follows an EDR 8DPSK design in a Bluetooth protocol: The first symbol is a reference, and bits of the last <NUM> symbols are <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

(<NUM>) Referring to <FIG>, a CRC design follows a CRC structure of a BLE PDU, that is, a CRC includes a total of <NUM> bits. An LFSR function is X24 + X10 + X9 + X6 + X4 + X3 + X + <NUM>.

(<NUM>) Referring to <FIG>, a trailer of the DPSK is all-zero bits of two symbols.

A trailer bit of a DQPSK modulation scheme is {<NUM>, <NUM>}, and a trailer bit of a D8PSK modulation scheme is {<NUM>, <NUM>}.

The radio frequency module <NUM> sends, to a radio frequency module <NUM>, the PDU including the audio data.

The radio frequency module <NUM> receives data from an air interface, and then transmits the data to a Bluetooth baseband module <NUM> for demodulation, and then transmits the data to an ACL and audio connection management module <NUM>.

The ACL and audio connection management module <NUM> is responsible for extracting the audio data and buffering the audio data, and transmitting the audio data to a serial communication module <NUM> or a pulse code modulation module <NUM>.

S9: The audio receiving device <NUM> receives the audio data.

The serial communication module <NUM> or the pulse code modulation module <NUM> transmits the audio data to an audio codec module <NUM> or a serial communication module <NUM>.

S10: A Bluetooth host protocol stack module <NUM> receives the audio data.

The audio codec module <NUM> or the serial communication module <NUM> transmits the audio data to the Bluetooth host protocol stack module <NUM>.

The Bluetooth host protocol stack module <NUM> decodes the audio data and transmits the audio data to an audio application. The audio application can play the audio data through an audio interface of the audio receiving device <NUM>.

In an optional case, the audio receiving device <NUM> returns an acknowledgement message to the audio source device <NUM>, where the acknowledgement message is used to indicate a receiving status of the audio data. In an example, the acknowledgement message may be a BLE empty packet. Because the empty packet uses the GFSK modulation scheme, an anti-interference capability is strong, thereby facilitating receiving by the audio source device <NUM>.

For example, <FIG> is a schematic flowchart of negotiating an audio codec parameter according to an embodiment of this application. The negotiation may specifically include the following steps.

<NUM>: An audio source device sends a GET_AUDIO_CODEC_CAPACITY_REQ message.

After an ACL connection is established between a sending device and a receiving device, the sending device may query an audio codec codec parameter of the receiving device; and correspondingly, the receiving device may also query a codec parameter of the sending device.

<FIG> is a schematic flowchart of querying an audio codec capability according to an embodiment of this application. An audio codec capability is queried based on a logical link control and adaptation protocol (L2CAP) channel.

Before the sending device transmits audio data to the receiving device, an audio source device <NUM> queries a codec parameter by using a Bluetooth controller of a sending device <NUM>, a Bluetooth controller <NUM> of the receiving device, and an audio receiving device <NUM>.

First, the audio source device <NUM> sends the GET_AUDIO_CODEC_CAPACITY_REQ message by using the Bluetooth controller <NUM> of the sending device, the Bluetooth controller <NUM> of the receiving device, and the audio receiving device <NUM>, to learn of a codec index. The codec index includes an identifier of the codec parameter. In an example, the codec index includes a codec <NUM> and a codec <NUM>.

Table <NUM> shows an example format of the GET_AUDIO_CODEC_CAPACITY_REQ message provided in this embodiment of this application.

In Table <NUM>, a valid range of the session identifier may be <NUM> to <NUM>.

The command identifier of the message is GET_AUDIO_CODEC_CAPACITY_REQ, and has a value of <NUM>.

The codec index starts from <NUM>. For example, when the codec index is 0xff, all codec capabilities are returned.

<NUM>: The audio receiving device <NUM> sends GET_AUDIO_CODEC_CAPACITY_RSP.

Then the audio receiving device <NUM> sends the GET_AUDIO_CODEC_CAPACITY_RSP by using the Bluetooth controller <NUM> of the receiving device, the Bluetooth controller <NUM> of the sending device, and the audio source device <NUM>, to respond to codec capability query request information, so that the audio source device <NUM> learns of a codec parameter. In an example, the codec index includes a codec <NUM> and a codec <NUM>, and the GET_AUDIO_CODEC_CAPACITY_RSP message includes a codec parameter with <NUM> and a codec parameter with <NUM>.

Table <NUM> shows an example format of the GET_AUDIO_CODEC_CAPACITY_RSP provided in this embodiment of this application.

The command identifier is GET_AUDIO_CODEC_CAPACITY_RSP, and has a value of <NUM>.

Table <NUM> shows an example of a data structure of a codec parameter provided in this embodiment of this application.

It should be understood that the message formats shown in Table <NUM> to Table <NUM> are merely examples for description in the embodiments of this application, and are not intended to limit a message format. The values and the ranges of the parameters provided in the tables are also optional. Neither a message format nor a parameter value is limited in this application.

For example, based on the obtained codec capability, the audio source device configures specific codec codec parameters, for example, a negotiated encoding type for transmitting audio data between the audio source device and the audio receiving device, a transmission mode, a sampling rate, and an audio channel, to ensure that the audio source device and the audio receiving device use consistent codec parameters.

<FIG> is a schematic flowchart of configuring an audio codec according to an embodiment of this application. The audio codec configuration procedure specifically includes the following steps.

<NUM>: An audio source device <NUM> sends an AUDIO_CONFIG_CODEC_REQ message.

First, the audio source device <NUM> sends the AUDIO_CONFIG_CODEC_REQ message by using a Bluetooth controller <NUM> of a sending device, a Bluetooth controller <NUM> of a receiving device, and an audio receiving device <NUM>, to select a codec parameter based on a codec index. In an example, if the codec index includes a codec <NUM> and a codec <NUM>, a codec parameter with <NUM> and a codec parameter with <NUM> may be returned in the GET_AUDIO_CODEC_CAPACITY_RSP message.

Table <NUM> shows an example format of the AUDIO_CONFIG_CODEC_REQ message provided in this embodiment of this application.

In Table <NUM>, the session identifier starts from <NUM>, and is used to distinguish between different requests.

The command identifier is AUDIO_CONFIG_CODEC_REQ, and has a value of <NUM>.

A valid value of the codec index starts from <NUM>. For example, the codec index may be selected from a codec list returned in the GET_AUDIO_CODEC_CAPACITY_RSP message shown in Table <NUM>.

<NUM>: The audio receiving device <NUM> sends an AUDIO_CONFIG_CODEC_CFM message.

Then the audio receiving device <NUM> sends the AUDIO_CONFIG_CODEC _CFM message to the audio source device <NUM> by using the Bluetooth controller <NUM> of the receiving device and the Bluetooth controller <NUM> of the sending device, to notify the audio source device <NUM> of a configuration status of a codec parameter. In an example, if the configuration status is <NUM>, it indicates that the codec parameter is successfully configured; or if the configuration status is not <NUM>, it indicates that the codec parameter is unsuccessfully configured.

Table <NUM> shows an example format of the AUDIO_CONFIG_CODEC_CFM message provided in this embodiment of this application.

In Table <NUM>, the session identifier starts from <NUM>, and corresponds to a session identifier of the received AUDIO_CONFIG_CODEC_REQ message.

The command identifier is AUDIO_CONFIG_CODEC_CFM, and has a value of <NUM>.

For the configuration status, <NUM> indicates a success, and another value indicates an error.

For example, for ease of understanding of a process of creating an audio connection, namely, S3, <FIG> is a signaling flowchart of a method for creating an audio connection according to an embodiment of this application.

<NUM>: An audio source device <NUM> sends a Setup audio stream command to a Bluetooth controller <NUM>.

It should be understood that, before the audio source device sends data to an audio receiving device, an audio connection needs to be created. In this embodiment of this application, a data transmission rate of a physical channel for transmitting an audio stream includes <NUM> Mb/s, <NUM> Mb/s, <NUM> Mb/s, or <NUM> Mb/s. Therefore, in a process of creating an audio connection, a physical channel for transmitting an audio stream needs to be determined.

For example, the audio source device <NUM> sends the Setup audio stream command to the Bluetooth controller <NUM>, to notify the audio receiving device of a physical channel on which the audio stream is transmitted. In an example, <NUM> indicates a physical channel at a rate of <NUM> Mb/s; <NUM> indicates a physical channel at a rate of <NUM> Mb/s; <NUM> indicates a physical channel at a rate of <NUM> Mb/s; and <NUM> indicates a physical channel at a rate of <NUM> Mb/s. The physical channel for transmitting the audio stream can be learned of by using a number.

For example, Table <NUM> shows a format of the Setup audio stream command provided in this embodiment of this application. Phy type may be used to identify the physical channel for transmitting the audio stream.

<NUM>: The Bluetooth controller <NUM> sends a Setup audio command Complete Event message to the audio source device <NUM>.

For example, the Bluetooth controller <NUM> notifies, based on the Setup audio command Complete Event message, the audio source device <NUM> of a result of executing the Setup audio stream command. Optionally, the Bluetooth controller <NUM> allocates an audio connection identifier to a current audio stream by using the Setup audio command Complete Event message.

For example, Table <NUM> shows a format of the Setup audio command Complete Event message provided in this embodiment of this application.

In an optional case, when a "status" of the Setup audio command Complete Event message returned by the Bluetooth controller to the audio source device is <NUM>, it indicates that an audio stream setup command is successfully executed; or optionally, when a "status" is <NUM>, it indicates that an audio stream setup command parameter is invalid.

<NUM>: The audio source device <NUM> sends an Enable audio stream command to the Bluetooth controller <NUM>.

For example, the Enable audio stream command is used to enable or disable an audio stream command, that is, whether the audio source device agrees or disagrees to transmit the current audio stream by using an audio connection identifier that is allocated by using a Setup audio command Complete Event.

For example, Table <NUM> shows an example format of the Enable audio stream command provided in this embodiment of this application.

For example, when "enable" in the Enable audio stream command is <NUM>, it indicates that the audio source device disagrees to transmit the current audio stream by using the allocated audio connection identifier; or optionally, when "enable" in the Enable audio stream command is <NUM>, it indicates that the audio source device agrees to transmit the current audio stream by using the allocated audio connection identifier.

<NUM>: The Bluetooth controller <NUM> sends an Enable audio stream command Status message to the audio source device <NUM>.

The Enable audio stream command Status message is used to return a status after the Enable audio stream command is executed, that is, notify the audio source device of whether the Enable audio stream command is successfully executed.

For the Enable audio stream command Status message, for example, Table <NUM> shows a format of the Enable audio stream command Status message provided in this embodiment of this application.

<NUM>: The Bluetooth controller <NUM> sends an AUDIO_CONNECTION_REQ message to the Bluetooth controller <NUM>, to request to set up an audio connection between the sending device and the receiving device.

For example, Table <NUM> shows a format of the AUDIO_CONNECTION_REQ message provided in this embodiment of this application.

<NUM>: The Bluetooth controller <NUM> sends an Audio stream req event message to the audio receiving device <NUM>, to notify the audio receiving device <NUM> that there is an audio connection request.

For example, Table <NUM> shows a format of the Audio stream req event message provided in this embodiment of this application.

<NUM>: The audio receiving device <NUM> sends an Audio stream accept command message to the Bluetooth controller <NUM>, so that the audio receiving device <NUM> instructs the Bluetooth controller <NUM> to accept the audio connection request.

For example, Table <NUM> shows a format of the Audio stream accept command message provided in this embodiment of this application.

For example, the Audio stream accept command message carries an audio connection identifier. Optionally, the audio connection identifier may be any integer ranging from <NUM> to <NUM>, and an audio connection on which a current audio data stream is transmitted is determined by using the audio connection identifier.

<NUM>: The Bluetooth controller <NUM> sends an AUDIO_CONNECTION_RSP message to the Bluetooth controller <NUM>. For example, the AUDIO_CONNECTION_RSP message may be an ACL control PDU message, and is used to return a message status to the Bluetooth controller <NUM> by using a parameter. In an example, when the parameter is <NUM>, the returned message status is "accepting the AUDIO_CONNECTION_REQ message"; or when the parameter is <NUM>, the returned message status is "invalid parameter"; or when the parameter is <NUM>, the returned message status is "system busy"; or when the parameter is <NUM>, the returned message status is "insufficient resources".

For example, Table <NUM> shows a format of the AUDIO_CONNECTION_RSP message provided in this embodiment of this application.

<NUM>: The Bluetooth controller <NUM> sends an AUDIO_CONNECTION_CONFIRM message to the Bluetooth controller <NUM>, to indicate that the audio connection request can be accepted.

For example, Table <NUM> shows a format of the AUDIO_CONNECTION_CONFIRM message provided in this embodiment of this application.

<NUM>: The Bluetooth controller <NUM> sends an Audio connection ready event message to the audio receiving device <NUM>.

The Bluetooth controller <NUM> notifies, based on the Audio connection ready event message, the audio source device <NUM> that the audio connection is already established, or the Bluetooth controller <NUM> may notify, based on the Audio connection ready event message, the audio receiving device <NUM> that the audio connection is already established; and then the audio data can be transmitted between the audio source device <NUM> and the audio receiving device <NUM>.

For example, Table <NUM> shows a message structure of the Audio connection ready event event provided in this embodiment of this application.

<NUM>: The audio source device <NUM> sends audio stream data to the Bluetooth controller <NUM>.

The audio data is transmitted by the audio source device <NUM> to the Bluetooth controller <NUM> through a host controller interface (HCI) or an inter-integrated circuit sound bus (I2S) interface after the audio source device <NUM> performs compression coding (lossy or lossless) on audio pulse code modulation (PCM) data at an application layer.

<NUM>: The Bluetooth controller <NUM> sends LL_AUDIO_DATA to the Bluetooth controller <NUM>.

The Bluetooth controller <NUM> sends, to the Bluetooth controller <NUM>, a PDU including the audio data.

Modulation of the audio data is described below with reference to <FIG>.

<FIG> is a schematic diagram of distribution of audio transmission channels according to an embodiment of this application.

A Bluetooth basic rate (BR) and an EDR mode are based on a bandwidth of <NUM>, channel center frequencies are <NUM>, <NUM>, <NUM>,. , <NUM>, and <NUM>, and there are a total of <NUM> channels.

BLE is based on a bandwidth of <NUM>, channel center frequencies are <NUM>, <NUM>, <NUM>,. , <NUM>, and <NUM>, and there are a total of <NUM> channels.

In this embodiment of this application, there are two bandwidths for high-definition audio transmission: <NUM> and <NUM>. For coexistence of Bluetooth channels and to reduce interference between existing Bluetooth channels, in a high-definition <NUM> mode, same BLE <NUM> physical channels are distributed, while in a high-definition <NUM> mode, BLE <NUM> physical channels are aggregated to combine two adjacent <NUM> physical channels into a <NUM> physical channel, where a center frequency of the <NUM> physical channel is equal to an average value of center frequencies of the two adjacent <NUM> physical channels. There are a total of <NUM> channels for the high-definition <NUM> mode, and this conforms to an access requirement for at least <NUM> channels for a frequency hopping system in many countries.

In an optional case, voice transmission in a Bluetooth protocol is performed in the EDR mode, a frame header is modulated by using a GFSK scheme having a modulation factor of <NUM>, a payload is modulated by using DQPSK or 8DPSK, and a symbol rate is <NUM>. A bit rate of the DQPSK is twice the symbol rate, namely, <NUM> Mbps; and a bit rate of the 8DPSK is three times the symbol rate, namely, <NUM> Mbps. It should be understood that, in this embodiment of this application, the symbol rate may also be referred to as a modulation rate, or the bit rate may also be referred to as a data transmission rate.

A feature of EDR is to increase a data transmission rate of a Bluetooth technology to <NUM> Mbps. In addition to achieving more stable audio stream transmission and lower power consumption, an advantage of a bandwidth can be fully used to connect a plurality of Bluetooth devices.

BLE is a low-cost, short-range, interoperable, and robust wireless technology. The BLE uses many intelligent means to minimize power consumption. Specifically, a variable connection time interval may be used, and the interval may be set to several milliseconds to several seconds based on a specific application. In addition, because the BLE uses a very fast connection method, a power-saving state can be maintained usually. In this case, two ends of a link only know that a peer end is still connected. The link is enabled only when necessary, and then the link is disabled in a shortest possible time.

In this embodiment of this application, the PDU including the audio data may be encapsulated based on a physical layer frame header, to obtain an audio data packet. The physical layer frame header is modulated by using a first digital modulation scheme, and the PDU is modulated by using a second digital modulation scheme. A value of a modulation rate of the first digital modulation scheme is equal to a value of a data transmission rate, and a value of a modulation rate of the second digital modulation scheme is less than the value of the data transmission rate. In this way, the audio data packet can be sent at the data transmission rate on a BLE physical channel. It should be understood that a modulation rate of a modulation scheme is a symbol rate in a unit of hertz Hz, a data transmission rate is a bit rate in a unit of bps, and there is usually a proportional relationship between a value of the modulation rate of the modulation scheme and a value of the data transmission rate. For example, one symbol in the GFSK modulation scheme carries one information bit, and therefore, a modulation rate (symbol rate) of the GFSK modulation scheme is equal to the data transmission rate (bit rate); one symbol in the DQPSK modulation scheme carries two information bits, and therefore, a modulation rate (symbol rate) of a <NUM>*DQPSK modulation scheme is equal to the data transmission rate (bit rate); and one symbol in the 8DPSK modulation scheme carries three information bits, and therefore, a modulation rate (symbol rate) of a <NUM>*DQPSK modulation scheme is equal to the data transmission rate (bit rate). It should be understood that, because the unit of the modulation rate is different from that of the data transmission rate, the foregoing proportional relationship indicates a proportion between the values, regardless of the unit.

There are three modulation methods for a digital signal: amplitude modulation, frequency modulation, and phase modulation. Other various modulation methods are improved combinations of the three methods. GMSK is an improvement of minimum shift keying (MSK), and is to insert a Gaussian low-pass pre-modulation filter before an MSK modulator to increase spectrum utilization and improve communication quality.

In an example, the modulation scheme for the frame header may be the GFSK. In addition, when the modulation factor of the GFSK is equal to a modulation factor of GFSK in the BLE, an original hardware device can be used, without a need to update a device, thereby saving hardware resources. The modulation factor of the GFSK in the BLE ranges from <NUM> to <NUM>, that is, the modulation factor of the GFSK in the BLE is greater than or equal to <NUM>, and less than or equal to <NUM>.

In this embodiment of this application, the audio data may be transmitted based on the EDR mode. For combination with a Bluetooth BLE mode, the modulation factor of the GFSK of the physical layer frame header is equal to the modulation factor of the GFSK in the BLE. That is, the physical layer frame header uses the GFSK scheme having a modulation factor ranging from <NUM> to <NUM>, and the payload uses the DQPSK or the 8DPSK.

In this embodiment of this application, the modulation scheme for the physical layer frame header is referred to as the first digital modulation scheme, and the modulation scheme for the payload is referred to as the second digital modulation scheme. A relationship between the first digital modulation scheme and the second digital modulation scheme and the data transmission rate may be: The value of the modulation rate of the first digital modulation scheme is equal to the value of the data transmission rate, and the value of the modulation rate of the second digital modulation scheme is less than the value of the data transmission rate.

The physical layer frame header is modulated by using the first digital modulation scheme, and the PDU is modulated by using the second digital modulation scheme. Because the physical layer frame header and the PDU are modulated by using two different modulation schemes, the modulation rate of the physical layer frame header is different from the modulation rate of the PDU, and the modulation rate of the modulation scheme for the PDU is lower than the data transmission rate, that is, a same symbol can carry more bits, thereby increasing an audio data transmission rate. Therefore, transmission of high-definition audio data can be supported.

In an example, the data transmission rate is N times the modulation rate of the second digital modulation scheme, where N is an integer greater than <NUM>.

In this embodiment of this application, the modulation scheme that can be used by the physical layer frame header is the GFSK, and the modulation scheme that can be used by the payload is the DQPSK or the 8DPSK.

For the GFSK modulation scheme, the data transmission rate is equal to the modulation rate of the GFSK.

For the DQPSK modulation scheme, the data transmission rate is twice the modulation rate of the DQPSK.

For the 8DPSK modulation scheme, the data transmission rate is three times the modulation rate of the 8DPSK.

In this embodiment of this application, a modulation rate of a high-definition <NUM> mode is <NUM>, a data transmission rate of GFSK in the high-definition <NUM> mode is <NUM>, a data transmission rate of DQPSK in the high-definition <NUM> mode is twice the modulation rate, namely, <NUM> Mbps, and a data transmission rate of 8DPSK is three times the modulation rate, namely, <NUM> Mbps.

A modulation rate of a high-definition <NUM> mode is <NUM>, a data transmission rate of GFSK in the high-definition <NUM> mode is <NUM>, a data transmission rate of DQPSK in the high-definition <NUM> mode is twice the modulation rate, namely, <NUM> Mbps, and a data transmission rate of 8DPSK is three times the modulation rate, namely, <NUM> Mbps.

It can be learned from the foregoing content that, in the high-definition <NUM> mode, a highest data transmission rate is <NUM> Mbps; and in the high-definition <NUM> mode, a highest data transmission rate is <NUM> Mbps.

Apparently, based on the technical solution in this embodiment of this application, the value of the data transmission rate is greater than <NUM> Mb/s. In this way, transmission of high-definition audio data can be supported.

Table <NUM> shows a correspondence between a Bluetooth voice and a bit rate. It can be learned from content in Table <NUM> that, in this embodiment of this application, the audio data can be transmitted on a physical channel having a bandwidth of <NUM> or a bandwidth of <NUM> based on the EDR mode. The frame header may be modulated by using the GFSK having a modulation factor that is equal to a BLE modulation factor. The payload is modulated by using the DQPSK or the 8DPSK. In this way, the audio data can be transmitted in the EDR mode on the BLE channel.

After receiving the acknowledgement message, the audio source device may end the audio connection. The audio data is transmitted to the audio receiving device <NUM> by using the audio source device <NUM>, the Bluetooth controller <NUM>, and the Bluetooth controller <NUM>.

<FIG> is a schematic flowchart of ending an audio connection according to an embodiment of this application.

<NUM>: An audio source device <NUM> sends an Enable audio stream command to a Bluetooth controller <NUM>.

The audio source device <NUM> sends the Enable audio stream command to the Bluetooth controller <NUM>, to apply to the Bluetooth controller <NUM> for ending an audio connection.

For example, for a message format of the Enable audio stream command provided in this embodiment of this application, refer to Table <NUM>, where an enable parameter is <NUM>, and <NUM> indicates ending an audio connection.

The Bluetooth controller <NUM> sends the Enable audio stream command Status message to the audio source device <NUM>, to return, to the audio source device <NUM>, a status after the Enable audio stream command is executed.

For example, for a message format of the Enable audio stream command Status message provided in this embodiment of this application, refer to Table <NUM>.

<NUM>: The Bluetooth controller <NUM> sends an AUDIO_DISCONNECT_REQ message to a Bluetooth controller <NUM>.

The Bluetooth controller <NUM> sends the AUDIO_DISCONNECT_REQ message to the Bluetooth controller <NUM>, to determine that an identifier for ending the audio connection is required.

For example, for a format of the AUDIO_DISCONNECT_REQ message provided in this embodiment of this application, refer to Table <NUM>.

<NUM>: The Bluetooth controller <NUM> sends an AUDIO_DISCONNECT_CFM message to the Bluetooth controller <NUM>.

The Bluetooth controller <NUM> sends the AUDIO_DISCONNECT_CFM message to the Bluetooth controller <NUM>, to determine that the identifier for ending the audio connection is required.

For example, for a format of the AUDIO_DISCONNECT_CFM message provided in this embodiment of this application, refer to Table <NUM>.

<NUM>: The Bluetooth controller <NUM> sends an Audio stream disconnected event event to the audio receiving device <NUM> by using the audio source device <NUM> and the Bluetooth controller <NUM>.

The Bluetooth controller <NUM> sends the Audio stream disconnected event event to the audio source device <NUM>, and the Bluetooth controller <NUM> sends the Audio stream disconnected event to the audio receiving device <NUM>, to notify whether the audio connection is successfully ended.

For example, for a format of the Audio stream disconnected event event provided in this embodiment of this application, refer to Table <NUM>.

So far, in this embodiment of this application, an audio codec parameter is first negotiated, and then the audio codec parameter is configured. After the audio connection is created, the audio source device <NUM> transmits audio with the audio receiving device <NUM> by using the Bluetooth controller <NUM> and the Bluetooth controller <NUM>. Finally, the audio connection is ended.

<FIG> is a schematic flowchart of an audio data transmission method according to an embodiment of this application. This embodiment of this application is performed by a sending device. The audio data transmission method specifically includes the following steps.

S1301: Encapsulate, based on a physical layer frame header, a PDU including audio data, to obtain an audio data packet, where the physical layer frame header is modulated by using a first digital modulation scheme, the PDU is modulated by using a second digital modulation scheme, a value of a modulation rate of the first digital modulation scheme is equal to a value of a data transmission rate, and a value of a modulation rate of the second digital modulation scheme is less than the value of the data transmission rate.

The sending device needs to send the audio data to a receiving device. The sending device modulates the frame header based on the first digital modulation scheme. In an example, a modulation scheme for a data signal may be GFSK.

For combination with a Bluetooth BLE mode, the frame header may use a GFSK scheme having a modulation factor ranging from <NUM> to <NUM>. The PDU is used to carry the audio data, and the PDU is modulated by using the second digital modulation scheme. In an example, the PDU may be modulated by using DQPSK or 8DPSK.

S1302: Send the audio data packet on a BLE physical channel at the data transmission rate.

The sending device can send the audio data packet on the BLE physical channel. In this way, the receiving device can receive the encapsulated PDU on the BLE physical channel.

In this embodiment of this application, the physical layer frame header is modulated by using the first digital modulation scheme, and the PDU is modulated by using the second digital modulation scheme. Because the physical layer frame header and the PDU are modulated by using two different modulation schemes, the modulation rate of the modulation scheme for the PDU is lower than the data transmission rate, that is, a same symbol can carry more bits, thereby increasing an audio data transmission rate. Therefore, transmission of high-definition audio data can be supported.

In an embodiment of this application, a codec generates a modulation scheme identifier of the BLE physical channel, so that based on the modulation scheme identifier, it can be determined that the physical layer frame header uses the first digital modulation scheme and the PDU uses the second digital modulation scheme; and sends the modulation scheme identifier. The modulation scheme used by the physical layer frame header and the modulation scheme used by the PDU can be determined based on the modulation scheme identifier. In this way, the sending device can modulate the physical layer frame header and the PDU by using the determined modulation schemes.

In an embodiment of this application, the data transmission rate is N times the modulation rate of the second digital modulation scheme. High-definition audio data can be transmitted on the BLE physical channel at the data transmission rate based on the PDU that is modulated by using the second digital modulation scheme. In an embodiment of this application, the control layer frame header includes indication information used to indicate a length of the audio data. In this way, the receiving device can verify, based on the indication information for the audio data in the control layer frame header, whether the received audio data is complete.

In an embodiment of this application, a bandwidth of the BLE physical channel is <NUM>; or a bandwidth of the BLE physical channel is <NUM>, and the physical channel having the bandwidth of <NUM> is formed by combining two adjacent physical channels each having a bandwidth of <NUM>. In this embodiment of this application, the audio data can be transmitted at different transmission rates by using different bandwidths.

In an embodiment of this application, the first digital modulation scheme includes the GFSK, and the second digital modulation scheme includes the DQPSK or the 8DPSK. In this way, compatibility between a BLE mode and an EDR mode is implemented, and power consumption can be reduced while the audio data is transmitted at a high speed.

In an embodiment of this application, a modulation factor of the GFSK ranges from <NUM> to <NUM>, so that an original hardware device can be used to implement the technical solution in this embodiment of this application, thereby saving hardware resources.

In an embodiment of this application, a codec codec parameter may be queried by using the L2CAP, and the codec parameter includes a coding parameter of the audio data; and original audio data is encoded based on the coding parameter, to obtain the audio data. Optionally, the audio data may be audio data on which a process such as encryption or integrity check is performed.

In an example, if the codec parameter has an index of <NUM> and is indicated by <NUM>, it indicates that the coding parameter supports a sampling rate <NUM> of <NUM> bits; or if the codec parameter has an index of <NUM> and is indicated by <NUM>, it indicates that the coding parameter supports a sampling rate <NUM> of <NUM> bits.

In this embodiment of this application, the coding parameter is queried by using the L2CAP, and the original audio data is encoded, to ensure normal audio play.

<FIG> is a schematic flowchart of an audio data transmission method according to another embodiment of the present application. This embodiment of this application may be performed by a receiving device. The audio data transmission method specifically includes the following steps.

S1401: Receive an audio data packet on a BLE physical channel, where the audio data packet includes a physical layer frame header and a PDU.

The receiving device may receive, on the BLE physical channel, the audio data packet sent by a sending device, where a bandwidth of the BLE physical channel is <NUM> or <NUM>.

S1402: Demodulate the physical layer frame header by using a first digital modulation scheme, and demodulate the PDU by using a second digital modulation scheme, to obtain audio data, where a value of a modulation rate of the first digital modulation scheme is equal to a value of a data transmission rate, and a value of a modulation rate of the second digital modulation scheme is less than the value of the data transmission rate.

The receiving device demodulates the physical layer frame header of the audio data packet by using the first digital modulation scheme, and demodulates the PDU of the audio data packet by using the second digital modulation scheme, to obtain the audio data.

In an example, the physical layer frame header is modulated based on GFSK, that is, the physical layer frame header of the audio data packet may be demodulated by using the GFSK.

The PDU of the audio data packet is demodulated by using the second digital modulation scheme, to obtain the audio data. In an example, the second digital modulation scheme is DQPSK or 8DPSK, and the PDU of the audio data packet is demodulated by using the DQPSK or the 8DPSK, to obtain the audio data.

In this embodiment of this application, the audio data packet is received on the BLE physical channel, the physical layer frame header is demodulated by using the first digital modulation scheme, and the PDU is demodulated by using the second digital modulation scheme. The modulation rate of the modulation scheme for the PDU is lower than the data transmission rate, that is, a same symbol can carry more bits, thereby increasing an audio data transmission rate, and supporting transmission of high-definition audio data. In an embodiment of this application, the receiving device may receive a modulation scheme identifier of the BLE physical channel. In this way, the receiving device may learn, based on the modulation scheme identifier, that the physical layer frame header uses the first digital modulation scheme and the PDU uses the second digital modulation scheme, to successfully demodulate the audio data.

In an embodiment of this application, when the receiving device receives or does not receive the audio data, an acknowledgement message needs to be returned to the sending device, where the acknowledgement message is used to indicate a receiving status of the audio data. For example, the receiving status of the audio data includes that the audio data is already received and/or the audio data is not received.

In an example, a BLE empty packet may be used, that is, the BLE empty packet is returned to the sending device, to indicate the receiving status of the audio data. Because the BLE empty packet uses a GFSK modulation scheme, an anti-interference capability is strong, thereby facilitating receiving by the sending device.

<FIG> is a schematic structural diagram of an audio data transmission device according to an embodiment of this application. The audio data transmission device corresponds to the audio data transmission method in <FIG>. The audio data transmission device in <FIG> specifically includes an audio source device <NUM>, a baseband processor <NUM>, and a transmitter <NUM>.

An audio source device <NUM> sends audio data to a baseband processor <NUM>; the baseband processor <NUM> encapsulates a PDU of the audio data; and then the transmitter <NUM> sends an audio data packet.

The audio source device <NUM> sends the audio data to the baseband processor.

The baseband processor <NUM> encapsulates, based on a physical layer frame header, the PDU including the audio data, to obtain the audio data packet, where a physical layer frame header is modulated by using a first digital modulation scheme, the PDU is modulated by using a second digital modulation scheme, a value of a modulation rate of the first digital modulation scheme is equal to a value of a data transmission rate, and a value of a modulation rate of the second digital modulation scheme is less than the value of the data transmission rate.

The transmitter <NUM> sends the audio data packet on a BLE physical channel at the data transmission rate.

For example, the audio source device <NUM> may be a power amplifier, a multimedia console, a digital audio mixer, an audio sampling card, a synthesizer, or the like.

In this embodiment of this application, the data transmission rate may be N times the modulation rate of the second digital modulation scheme, where N is an integer greater than <NUM>.

In this embodiment of this application, the PDU includes a control layer frame header and a payload; the payload is used to carry the audio data; and the control layer frame header includes indication information used to indicate a length of the audio data.

In this embodiment of this application, a bandwidth of the BLE physical channel is <NUM>; or a bandwidth of the BLE physical channel is <NUM>, and the physical channel having the bandwidth of <NUM> is formed by combining two adjacent physical channels each having a bandwidth of <NUM>.

In this embodiment of this application, the first digital modulation scheme may include GFSK, and the second digital modulation scheme may include DQPSK or 8DPSK.

In this embodiment of this application, a modulation factor of the GFSK ranges from <NUM> to <NUM>, that is, the modulation factor of the GFSK is greater than or equal to <NUM>, and less than or equal to <NUM>.

In this embodiment of this application, the audio source device <NUM> further includes an audio codec <NUM>. The audio codec <NUM> is configured to generate a modulation scheme identifier of the BLE physical channel. The baseband processor <NUM> may determine, based on the modulation scheme identifier, the modulation scheme used by the PDU. In this way, the baseband processor <NUM> of an audio sending device can modulate the physical layer frame header and the PDU by using the determined modulation schemes. Further, the transmitter <NUM> sends the modulation scheme identifier of the physical channel to a receiving device, so that the receiving device can demodulate the physical layer frame header and the PDU by using corresponding modulation schemes.

In this embodiment of this application, the audio codec <NUM> queries a codec parameter by using the L2CAP, where the codec parameter includes a coding parameter of the audio data. Further, the codec <NUM> encodes original audio data based on the coding parameter, to obtain the audio data. The coding parameter is queried by using the L2CAP, and the original audio data is encoded, to ensure normal audio play.

<FIG> is a schematic structural diagram of a receiving device according to an embodiment of this application, where an audio data transmission device corresponds to the audio data transmission method in <FIG>.

The audio data transmission device in <FIG> specifically includes a receiver <NUM>, a baseband processor <NUM>, and an audio receiving device <NUM>.

The receiver <NUM> receives an audio data packet on a BLE physical channel; the baseband processor <NUM> demodulates the audio data packet, to obtain audio data; and the audio receiving device <NUM> receives the audio data sent by the baseband processor <NUM>.

The receiver <NUM> receives the audio data packet on the BLE physical channel, where the audio data packet includes a physical layer frame header and a PDU.

The baseband processor <NUM> demodulates the physical layer frame header by using a first digital modulation scheme, and demodulates the PDU by using a second digital modulation scheme, to obtain audio data carried in a payload, where a value of a modulation rate of the first digital modulation scheme is equal to a value of a data transmission rate, and a value of a modulation rate of the second digital modulation scheme is less than the value of the data transmission rate.

The audio receiving device <NUM> receives the audio data from the baseband processor <NUM>.

In this embodiment of this application, the audio data packet is received on the BLE physical channel, the physical layer frame header is demodulated by using the first digital modulation scheme, and the PDU is demodulated by using the second digital modulation scheme. The modulation rate of the modulation scheme for the PDU is lower than the data transmission rate, that is, a same symbol can carry more bits, thereby increasing an audio data transmission rate, and supporting transmission of high-definition audio data. In an embodiment of this application, the audio receiving device <NUM> further includes an audio codec <NUM>.

The receiver <NUM> is configured to receive a modulation scheme identifier of the BLE physical channel.

The audio codec <NUM> is configured to: determine, based on the modulation scheme identifier, that the physical layer frame header uses the first digital modulation scheme, and determine, based on the modulation scheme identifier, that the PDU uses the second digital modulation scheme.

In this way, the first digital modulation scheme and the second digital modulation scheme can be determined based on the modulation scheme identifier, and then the audio data can be successfully demodulated.

In an embodiment of this application, a data transmission rate is N times the modulation rate of the second digital modulation scheme, where N is an integer greater than <NUM>.

In an embodiment of this application, when the receiver <NUM> receives or does not receive the audio data, an acknowledgement message needs to be returned to the sending device, where the acknowledgement message is used to indicate a receiving status of the audio data. For example, the receiving status of the audio data includes that the audio data is already received and/or the audio data is not received.

In an example, a BLE empty packet is used, that is, the BLE empty packet is returned to the sending device, to indicate the receiving status of the audio data. Because the BLE empty packet uses the GFSK modulation scheme, an anti-interference capability is strong, thereby facilitating receiving by the sending device.

<FIG> is an example diagram of a hardware architecture for transmitting audio data according to an embodiment of this application. As shown in <FIG>, a computing device <NUM> includes an input device <NUM>, an input interface <NUM>, a processor <NUM>, a memory <NUM>, an output interface <NUM>, and an output device <NUM>.

The input interface <NUM>, the processor <NUM>, the memory <NUM>, and the output interface <NUM> are connected to each other by using a bus <NUM>. The input device <NUM> and the output device <NUM> are connected to the bus <NUM> by respectively using the input interface <NUM> and the output interface <NUM>, to connect to another component of the computing device <NUM>.

Specifically, the input device <NUM> receives external input information, and transmits the input information to the processor <NUM> by using the input interface <NUM>. The processor <NUM> processes the input information according to a computer executable instruction stored in the memory <NUM>, to generate output information, temporarily or permanently stores the output information in the memory <NUM>, and then transmits the output information to the output device <NUM> through the output interface <NUM>. The output device <NUM> outputs the output information to the outside of the computing device <NUM> for use by a user.

The computing device <NUM> may perform the steps in the foregoing audio data transmission method in this application.

The processor <NUM> may be one or more central processing units (CPU). When the processor <NUM> or the processor <NUM> is one CPU, the CPU may be a single-core CPU or a multi-core CPU.

The memory <NUM> may be but is not limited to one or more of a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a compact disc read-only memory (CD-ROM), a hard disk, and the like. The memory <NUM> is configured to store program code.

All or some of the foregoing embodiments may be implemented by using software, hardware, firmware, or any combination thereof. When some or all of the foregoing embodiments are implemented in a form of a computer program product, the computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedure or functions according to the embodiments of this application are all or partially generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable apparatuses. The computer instructions may be stored in a computer-readable storage medium or may be transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, a computer, a server, or a data center to another website, computer, server, or data center in a wired (for example, a coaxial cable, an optical fiber, or a digital subscriber line (DSL)) or wireless (for example, infrared, radio, or microwave) manner. The computer-readable storage medium may be any usable medium accessible by a computer, or a data storage device, such as a server or a data center, integrating one or more usable media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, or a magnetic tape), an optical medium (for example, a DVD), a semiconductor medium (for example, a solid-state drive (SSD)), or the like.

Claim 1:
An audio data transmission method, wherein the method comprises:
encapsulating, by a baseband processor (<NUM>), based on a physical layer frame header, a protocol data unit, PDU, comprising audio data, to obtain an audio data packet, wherein the physical layer frame header is modulated by using a first digital modulation scheme, the PDU is modulated by using a second digital modulation scheme, a value of a symbol rate of the first digital modulation scheme is equal to a value of a bit rate of the first digital modulation scheme, and a value of a symbol rate of the second digital modulation scheme is less than a value of a bit rate of the second digital modulation scheme; and
characterized in that:
sending, by a transmitter (<NUM>), the audio data packet on a Bluetooth low energy, BLE, physical channel at the bit rate of the second digital modulation scheme, wherein a bandwidth of the BLE physical channel is <NUM> or <NUM>.