A true wireless stereo lossless audio transmission system and method based on ultra-wideband

Abstract

The application belongs to the technical field of wireless communication, and discloses a true wireless stereo sound transmission system and method based on ultra-wideband (UWB). The system uses UWB technology to realize high-bandwidth and low-delay lossless audio transmission, and solves the problems of traditional Bluetooth technology in sound quality, synchronization accuracy and anti-interference capability. The transmission method in the system includes lossless audio encoding and decoding, bandwidth adaptation, binaural independent transmission and precise synchronization, adaptive frequency hopping anti-interference and power consumption optimization. The high-bandwidth characteristic of UWB technology supports 24bit / 48kHz and above lossless audio transmission, the end-to-end delay is less than 10ms, the left and right ear synchronization error is less than 10us, and the power consumption is reduced through hierarchical wakeup and non-continuous transmission mechanism. The application is suitable for high sound quality, low delay true wireless stereo sound transmission scene, and has excellent anti-interference capability and low power consumption characteristics.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a true wireless stereo lossless audio transmission system and method based on ultra-wideband. Background Technology

[0002] Bluetooth audio transmission is a common audio transmission method. However, Bluetooth audio transmission often uses lossy encoding such as SBC / AAC / LDAC, which cannot support lossless audio transmission. At the same time, it is also limited in bandwidth. The most advanced Bluetooth technology can achieve a data rate of 990 lbps, but it is difficult to meet the data rate requirements of lossless audio transmission. In the master-slave architecture, the synchronization of the left and right earbuds in Bluetooth relies on protocol stack optimization, which is susceptible to environmental interference, causing sound field shift and resulting in low synchronization accuracy. Bluetooth is also congested in the 2.4 GHz band and is susceptible to interference from devices such as Wi-Fi and microwave ovens.

[0003] UWB technology is a high-bandwidth, low-latency, and highly interference-resistant technology that enables lossless audio transmission. However, applying UWB technology to audio transmission presents the following challenges: UWB is traditionally used in positioning scenarios, and continuous transmission of high-bandwidth audio requires power optimization; precise time synchronization and independent data transmission between the left and right earbuds are necessary; and the high bitrate of lossless audio requires optimization of encoding and decoding.

[0004] To address the above problems, this invention proposes a true wireless stereo lossless audio transmission system and method based on ultra-wideband. Summary of the Invention

[0005] The present invention aims to provide a true wireless stereo lossless audio transmission system and method based on ultra-wideband, so as to solve the problems of existing Bluetooth technology in terms of high sound quality, low latency and anti-interference capability.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A true wireless stereo lossless audio transmission method based on ultra-wideband (UWB) includes lossless audio encoding / decoding and broadband adaptation: the lossless audio encoding uses one of the lossless compression algorithms ADPCM, WAV, FLAC, and SCL6, combined with the high bandwidth characteristics of UWB to achieve lossless transmission; the bandwidth adaptation adjusts the encoding bitrate in real time according to the UWB channel quality, supporting ultra-high-definition lossless modes (greater than 10Mbps, supporting video transmission; greater than 2Mbps and less than 10Mbps, supporting lossless audio transmission; less than 1Mbps, supporting high-definition voice dialogue).

[0008] Binaural independent transmission and precise synchronization: Binaural transmission means that the audio device simultaneously sends independent audio streams to the left and right earbuds; precise synchronization is a synchronization mechanism based on UWB timestamps, which uses UWB's nanosecond-level timestamps to align the data packets of the left and right ears, achieving a synchronization error of <10us.

[0009] Adaptive frame hopping and anti-interference: Adaptive frame hopping dynamically selects UWB sub-bands to avoid interference from the Wi-Fi 6E band; it ensures transmission stability through a real-time frequency hopping strategy based on channel state information.

[0010] Power consumption optimization includes a graded wake-up mechanism and a discontinuous transmission mechanism. The graded wake-up mechanism wakes up the UWB RF module only before the audio data arrives. The discontinuous transmission mechanism utilizes the pulse characteristics of UWB to reduce average power consumption through burst transmission.

[0011] Furthermore, the steps to achieve independent binaural transmission and precise synchronization are as follows:

[0012] S1, The audio source device broadcasts a UWB synchronization beacon, which includes a global clock reference;

[0013] S2. After receiving the beacon, the left and right earbuds calibrate the local clock, with a local clock error of <100ns;

[0014] S3: Audio data is transmitted in a time-division manner, with the left and right earbuds independently parsing the audio stream based on timestamps.

[0015] Furthermore, the anti-interference methods are as follows: dynamic spectrum sensing, where the UWB receiver monitors the channel interference energy in real time and triggers frequency hopping to an idle sub-band; and forward error correction, which uses Reed-solomon coding to correct burst errors.

[0016] Furthermore, the power consumption optimization method is as follows: data prefetch buffering, the earbud UWB module wakes up once every 100ms, receives 1 second of audio data in batches and then enters sleep mode; earbud collaboration, the main earbud forwards time synchronization information to the secondary earbud through near-field magnetic induction, reducing the number of UWB activations.

[0017] A true wireless stereo lossless audio transmission system based on ultra-wideband is characterized in that the transmitting end and receiving end in the system adopt the above-mentioned audio transmission method.

[0018] Furthermore, the system's hardware audio source device integrates a UWB transmitter module, including one of the Qorvo DW3000, NXPSR150, and SPARK SR1020.

[0019] Furthermore, the transport layer in the software protocol stack of this system adopts a custom protocol frame structure, including a timestamp field, an audio data block, and a CRC check. The timestamp field is 67 bits and is used for binaural synchronization; the audio data block is 512 bytes and is used to encapsulate the FLAC encoded audio data; the CRC check is 32 bits and is used for cyclic redundancy check.

[0020] The beneficial effects of the technical solution are as follows: The method of the present invention, based on ultra-wideband technology, can effectively improve the audio quality of transmission, support lossless audio transmission, support lossless audio transmission of 24bit / 48kHz and above, and achieve a signal-to-noise ratio >120dB; When using the method of the present invention for audio transmission, the end-to-end transmission delay is <10ms, which is a significant improvement compared to the typical value of 20ms for existing Bluetooth LEAudio technology; The transmission method of the present invention has strong anti-interference capability, and the bit error rate is <1e-6 in Wi-Fi dense environments. Attached Figure Description

[0021] Figure 1 This is a transmission architecture diagram of the lossless UWB transmission system of the present invention;

[0022] Figure 2 This is a protocol stack control diagram in the lossless UWB transmission system of the present invention;

[0023] Figure 3 This is a diagram illustrating the transmission method strategy in the lossless UWB transmission system of the present invention. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0025] A true wireless stereo lossless audio transmission system based on ultra-wideband (UWB). In this system's hardware, the audio source device acts as the transmitter. This device integrates a UWB transmitter module compliant with the FiRa specification and IEEE 802.15.4z standard, such as the Qorvo DW3000, which supports multi-channel audio output. Figure 1 The above is a transmission architecture diagram of the transmission system of the present invention;

[0026] In this system, the TWS earbuds serve as the receiver, containing a UWB receiver module, a dedicated audio DSP chip, and a low-power microcontroller. The UWB receiver module is compatible with the IEEE 802.15.4z standard. The dedicated audio DSP chip is a Cirrus Logic CS47L35, used for real-time lossless decoding. The low-power microcontroller is a Nordic nRF5340, used to manage the UWB protocol stack.

[0027] like Figure 2The above is a protocol stack control diagram of the system of the present invention:

[0028] The physical layer of the software protocol stack in this system adopts the HRP (High Rate Pulse) UWB mode, supporting a data rate of 6.8 Mbps. Its electromagnetic wave frequency range is the 3.1-10.6 GHz ultra-high frequency band, achieving nanometer-level synchronization accuracy.

[0029] The transport layer of the software protocol stack in this system adopts a custom protocol frame structure, including a timestamp field, an audio data block, and a CRC checksum. The timestamp field is 64 bits and is used for binaural synchronization; the audio data block is 512 bytes and is used to encapsulate FLAC-encoded audio data; the CRC checksum is 32 bits and is used for 32-bit cyclic redundancy check.

[0030] The application layer of this system supports a compatible interface for LDAC / LHDC high-definition audio encoding formats.

[0031] The system employs the ADPCM lossless compression algorithm for lossless audio encoding, which, combined with the high bandwidth characteristics of UWB, enables lossless transmission. Bandwidth adaptation adjusts the encoding bitrate in real time based on the UWB channel quality. A bitrate greater than 10 Mbps supports video transmission; greater than 2 Mbps and less than 10 Mbps supports lossless audio transmission; and less than 1 Mbps supports high-definition voice communication.

[0032] like Figure 3 The above is a strategy diagram of the audio transmission method in the system of the present invention;

[0033] In this system, both the audio source device transmitter and the TWS earbud receiver use the following method for audio transmission: independent transmission and precise synchronization of both ears are used during audio transmission: S1, the audio source device broadcasts a UWB synchronization beacon, which includes a global clock reference; S2, after receiving the beacon, the left and right earbuds calibrate their local clocks, with a local clock error of <100ns; S3, audio data is transmitted in a time-division manner, and the left and right earbuds independently parse the audio stream according to the timestamp.

[0034] The anti-interference methods used in this system are: dynamic spectrum sensing, where the UWB receiver monitors the channel interference energy in real time and triggers frequency hopping to an idle sub-band; and forward error correction, which uses Reed-solomon coding to correct burst errors.

[0035] The power consumption optimization method adopted in this system is as follows: data prefetch buffer, the earbud UWB module wakes up once every 100ms, and enters sleep mode after receiving 1 second of audio data in batches; earbud collaboration, the main earbud forwards time synchronization information to the secondary earbud through near-field magnetic induction, reducing the number of UWB activations.

[0036] The system was tested and verified by transmitting audio from an audio source and receiving it with TWS earbuds. The sound quality was verified using an APx555 audio analyzer, and the THD+N was found to be <0.0005%. The delay error of the left and right channels was measured using an oscilloscope, and the delay error was found to be <15µs.

[0037] The results above show that the system using the method of the present invention for audio transmission can achieve high-quality lossless audio transmission, effectively reduce end-to-end transmission delay, and also has strong anti-interference capabilities.

[0038] The above descriptions are merely embodiments of the present invention, and common technical solutions or characteristics known in the schemes are not described in detail here. For those skilled in the art, various modifications and improvements can be made without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for true wireless stereo lossless audio transmission based on ultra-wideband, characterized in that, Includes lossless audio encoding / decoding and broadband adaptation: Lossless audio encoding uses one of the lossless compression algorithms ADPCM, WAV, FLAC, and SCL6, combined with the high bandwidth characteristics of UWB to achieve lossless transmission; bandwidth adaptation adjusts the encoding bitrate in real time according to the UWB channel quality: greater than 10Mbps, supports video transmission; greater than 2Mbps and less than 10Mbps, supports lossless audio transmission; less than 1Mbps, supports high-definition voice dialogue; Binaural independent transmission and precise synchronization: Binaural transmission involves the audio device simultaneously sending independent audio streams to the left and right earbuds; precise synchronization is a synchronization mechanism based on UWB timestamps, utilizing UWB's nanosecond-level timestamps to align the data packets of the left and right earbuds, achieving a synchronization error of <10µs; the implementation steps of the binaural independent transmission and precise synchronization are as follows: S1, the audio source device broadcasts a UWB synchronization beacon, including a global clock reference; S2, after receiving the beacon, the left and right earbuds calibrate their local clocks, with a local clock error of <100ns; S3, audio data is transmitted in a time-division manner, with the left and right earbuds independently parsing the audio stream according to the timestamp; Adaptive frame hopping and anti-interference: Adaptive frame hopping dynamically selects UWB sub-bands to avoid interference from the Wi-Fi 6E band; a real-time frequency hopping strategy based on channel state information ensures transmission stability; the anti-interference method specifically includes: dynamic spectrum sensing, where the UWB receiver monitors channel interference energy in real time and triggers frequency hopping to an idle sub-band; and forward error correction, using Reed-solomon coding to correct burst errors. Power consumption optimization includes a tiered wake-up mechanism and a discontinuous transmission mechanism. The tiered wake-up mechanism wakes up the UWB RF module only before the audio data arrives. The discontinuous transmission mechanism utilizes the pulse characteristics of UWB to reduce average power consumption through burst transmission. The power consumption optimization method is as follows: data prefetch buffer, the earphone UWB module wakes up once every 100ms, and enters sleep mode after receiving 1 second of audio data in batches. Earbud collaboration: the primary earbud forwards time synchronization information to the secondary earbud via near-field magnetic induction, reducing the number of UWB activations.

2. A true wireless stereo lossless audio transmission system based on ultra-wideband, characterized in that, The transmitting and receiving ends in this system employ the audio transmission method described in claim 1.

3. The true wireless stereo lossless audio transmission system based on ultra-wideband as described in claim 2, characterized in that: The system's hardware audio source device integrates a UWB transmitter module, including one of the Qorvo DW3000, NXP SR150, or SPARKSR1020.

4. The true wireless stereo lossless audio transmission system based on ultra-wideband according to claim 2, characterized in that: The transport layer in the software protocol stack of this system adopts a custom protocol frame structure, including a timestamp field, an audio data block, and a CRC check. The timestamp field is 67 bits and is used for binaural synchronization; the audio data block is 512 bytes and is used to encapsulate FLAC encoded audio data. The CRC check is 32 bits, used for cyclic redundancy check.

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