KR20070098077A - System and method for transmitting-receiving multicaannel audio data using bluetooth - Google Patents

Abstract

A system and method for transmitting and receiving wireless multichannel audio data using Bluetooth are provided to secure a bandwidth for large capacity multichannel audio signals by transmitting multichannel digital audio data using an ACL(Asynchronous Connectionless) link capable of transmitting and receiving non-voice data, not an SCO(Synchronous Connection-Oriented) link having a limited bandwidth. A multichannel audio transmitting/receiving system using Bluetooth consists of a transmitting unit(200) and a receiving unit(100). The transmitting unit(200) comprises a multichannel audio decoder(210), a serial audio signal input part(220), an audio signal extractor(230), a Bluetooth transmitter(240), and a Bluetooth module(250). The multichannel audio decoder(210) receives a multichannel digital audio signal through an S/PDIF port from a signal source(100) and decodes it into serial audio data. The serial audio signal input part(220) receives the serial audio data from the multichannel audio decoder(210). The audio signal extractor(230) extracts digital audio data from the serial audio data. The Bluetooth transmitter(240) receives the extracted digital audio data from the audio signal extractor(230) and carries Bluetooth stacks with the digital audio data to the receiving unit(100) through the Bluetooth module(250).

Description

Wireless multi-channel audio transmission and reception system and method using Bluetooth {SYSTEM AND METHOD FOR TRANSMITTING-RECEIVING MULTICAANNEL AUDIO DATA USING BLUETOOTH}

1 is a Bluetooth stack structure diagram for explaining a conventional Bluetooth audio transmission system.

2 is a block diagram showing a wireless multi-channel audio transmission and reception system using Bluetooth to which the present invention is applied.

3 is a flowchart illustrating a wireless multi-channel audio transmission and reception method using Bluetooth according to the present invention.

The present invention relates to a wireless multi-channel audio transmission and reception system and method using Bluetooth, and more particularly, to transmit and receive a large amount of multi-channel audio data among digital audio data at a smooth speed in transmitting and receiving wireless audio signals through short-range Bluetooth communication. The present invention relates to a wireless multi-channel audio transmission and reception system and method using Bluetooth to enable a multi-channel audio device to be a Bluetooth device.

Recently, as the home theater function has emerged to the general public, the audio portion of the image media has gained a great deal of attention.

For example, among the digital audio signal formats, sounds for AC-3, PCM, and MPEG are mainly combined with DVD players. That is, DVD titles compress audio in such a digital audio signal format, and most of these DVD titles are produced in a 5.1-channel multichannel audio format.

There are 8 multichannel audio formats (<1 + 1: ch1, ch2>, <1/0: C>, <2/0: L, R>, <3/0: L, C, R>, < 2/1: L, R, S>, <3/1: L, C, R, S>, <2/2: L, R, SL, SR>, <3/2: L, C, R, SL, SR>).

On the other hand, Blue Tooth, a new technology that has been in the spotlight recently, is a technology that will open the network era of digital devices such as mobile phones, personal digital assistants (PDAs), personal computers (PCs), and televisions and set-top boxes. It is attracting attention as a protagonist to bring new vitality.

Bluetooth is a standard that can transmit and receive data at high speed without using physical cables by using 2.4GHz frequency hopping method between various electronic devices within a short range (10 to 100 meters). Currently, in order to transmit and receive data between mobile terminals or between a mobile terminal and a desktop personal computer, a physical cable suitable for each mobile terminal standard must be connected, and a program corresponding thereto must be executed.

The commercialization of Bluetooth enables wireless high-speed data transmission and reception between Bluetooth-enabled personal digital assistants, notebooks, desktop personal computers, printers, digital cameras, and other Post-PCs, enabling complete wireless networking within short distances. Can be realized.

In practice, Bluetooth is a short-range data transmission / reception protocol, and the maximum speed that can be physically transmitted is 721 Kbit / sec, but protocol layers such as Host Controller Interface (HCI), Logical Link Control and Adaptation Protocol (L2CAP), and RFCOMM that are higher in the Bluetooth stack structure. In case of passing through, the transmission speed is lower than this due to header processing and packet retransmission for each layer.

1 shows a general stack structure of such a Bluetooth.

Referring to FIG. 1, in an audio data transmission / reception link of a Bluetooth system, a synchronous circuit-oriented link (SOC link), which is usually used for a voice audio signal, is used. By providing a point-to-point connection, that is, a synchronous method, transmission and reception of voice data or voice and non-voice data is possible.

This SOC link enables 64Kbit / sec communication in both directions.

However, since the amount of data of the above-described digital audio signal format is multi-channel audio format is larger than the general single channel audio signal, the bandwidth is not enough to transmit to the Bluetooth audio receiver through the existing SOC link. There is a shortage and there is a big problem in transmission speed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its object is to enable multi-channel audio to be transmitted and received at a smooth speed in a large amount of digital audio data in wireless audio transmission and reception through short-range Bluetooth communication. The present invention provides a wireless multi-channel audio transmission and reception system and method using Bluetooth to enable a device to be a Bluetooth device.

Wireless multi-channel audio transmission and reception system using Bluetooth according to an aspect of the present invention for achieving the above object, in a wireless multi-channel audio transmission and reception system using Bluetooth for transmitting and receiving audio signals via a Bluetooth interface, which is output from a signal source A multichannel audio decoder for receiving a multichannel digital audio signal and decoding the serial audio data; An audio signal extraction unit for extracting digital audio data for transmission from serial audio data transmitted from the multichannel audio decoder; A Bluetooth transmitter and module configured to receive digital audio data for transmission extracted by the audio signal extractor and to transmit the extracted data to asynchronous ACL link using a respective L2CAP stack; A Bluetooth receiver and module for receiving data transmitted from the Bluetooth transmitter and module and extracting digital audio data using an internal L2CAP stack; A serial audio signal output unit configured to receive the extracted digital audio data and to reconstruct and output the serial audio data; An audio processor which decodes serial audio data output through the serial audio signal output unit into digital audio data separated for each channel; And multi-channel processing means for receiving the decoded digital audio data for each channel, converting the digital audio data into an analog audio source, mixing each channel, and outputting the mixed audio channel to an audio output device. Characterized in that it comprises a.

Preferably, the digital audio signal of the signal source input to the multichannel audio decoder is S / PDIF (Sony / Philips Digital Interface) data format capable of processing the multichannel digital audio signal.

More preferably, the multi-channel audio decoder receives a digital audio signal by S / PDIF and analyzes the frequency, and analyzes the type and the number of channels based on the analyzed frequency and separates the signal according to the number of channels. The digital audio signal is output in a 12S (Inter-IC Sound) audio format, which is an audio format of serial audio data.

More preferably, the serial audio signal output unit may output digital audio data received and transmitted by the Bluetooth receiver and the module in a 12S (Inter-IC Sound) audio format, which is an audio format of serial audio data.

Wireless multi-channel audio transmission and reception method using Bluetooth according to another aspect of the present invention for achieving the above object, in a wireless multi-channel audio transmission and reception method using Bluetooth for transmitting and receiving audio signals between the transmitting device and the receiving device via a Bluetooth interface (a) receiving a multi-channel digital audio signal output from a digital signal source through a transmitting device, decoding the serial audio data, and extracting digital audio data for transmission from the decoded serial audio data; (b) connecting the transmitter and the receiver to an asynchronous ACL link and transmitting the extracted digital audio data to an asynchronous ACL link using an L2CAP stack; (c) receiving data transmitted from the transmitter through a receiver, extracting digital audio data using an internal L2CAP stack of the receiver, and reconstructing the extracted digital audio data into serial audio data. step; And (d) decoding the serial audio data into digital audio data separated for each channel, converting the decoded digital audio data into an analog audio source, and mixing and outputting each channel to an audio output device. Characterized in that it comprises a.

Preferably, in step (a), the digital audio signal input from the digital signal source is a S / PDIF (Sony / Philips Digital Interface) data format capable of processing a multichannel digital audio signal.

More preferably, in the step (a), the digital audio signal is received from the digital signal source by S / PDIF and the frequency is analyzed, and the type and the number of channels are analyzed based on the analyzed frequency. The method may further include outputting a digital audio signal separated according to the number of channels in a 12S (Inter-IC Sound) audio format, which is an audio format of serial audio data.

More preferably, the step (c) converts the digital audio data extracted using the internal L2CAP stack of the receiver into an 12-S (Inter-IC Sound) audio format, which is an audio format of serial audio data. It characterized in that it further comprises a process.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, the present invention provides a Bluetooth device which enables a multi-channel audio device to be a Bluetooth device by transmitting and receiving a wireless audio signal through short-range Bluetooth communication so that multi-channel audio data of digital audio data can be transmitted and received at a smooth speed. Although a wireless multi-channel audio transmission and reception system and method will be described as a preferred embodiment, the technical idea of the present invention is not limited thereto, but may be variously modified and modified by those skilled in the art.

In the embodiment of the present invention described below, the Bluetooth receiver is described as an example of the multi-channel Bluetooth headphones installed in the 6-channel headphones, but the present invention is not limited thereto, and is applicable to various multi-channel audio output devices. Of course it can.

2 is a block diagram illustrating a multi-channel audio transmission and reception system using Bluetooth according to the present invention.

As shown in FIG. 2, the multi-channel audio transmission / reception system to which the present invention is applied includes a transmitter 200 and the transmitter for transmitting the multi-channel digital audio data output from the signal source 100 through short-range Bluetooth communication. The receiver 300 is configured to receive the multi-channel digital audio data transmitted from the 200 and transmit the multi-channel dedicated headset 400.

The signal source 100 is a S / S multi-channel digital audio signal of the digital audio signal source 100 that is a device for outputting a multi-channel digital audio signal, such as a DVD player, a PC sound card, a video game machine, a portable multimedia player (PMP), etc. Output through the optical output port 120 in the PDIF data format.

Here, S / PDIF (Sony / Philips Digital Interface) is a digital output standard made by Sony and Philips among the digital output methods, and enables the digital audio signal to be processed in multiple channels.

The transmitter 200 includes a multi-channel audio decoder 210, a serial audio signal input unit 220, an audio signal extractor 230, a Bluetooth transmitter 240, and a Bluetooth module 250.

The multichannel audio decoder 210 receives a multichannel digital audio signal output from the signal source 100 in an S / PDIF data format through an S / PDIF port and decodes the serial audio data into serial audio data. Will print.

That is, the multi-channel audio decoder 130 receives a digital audio signal by S / PDIF and analyzes its frequency (48Khz, 44.1Khz, 32Khz, etc.) and based on the analyzed frequency, the type of the audio signal ( It analyzes the number of channels (AC-3, PCM, MPEG-1 Layer-2, etc.) and the number of channels and outputs the digital audio signal separated according to the number of channels in 12S (Inter-IC Sound) audio format, which is an audio format of serial audio data.

At this time, the 12S is a serial bus design for digital audio devices and technologies such as CD player, DSP, digital TV sound, etc. In the 12S design, audio data is processed separately from a clock signal. This separation of data and clock signals eliminates the need for jitter-preventing devices because no errors related to jitter-inducing time occur.

The 12S bus is composed of three serial bus lines, one line for time division multiplexed data channels, one word select line, and one clock line.

The serial audio signal input unit 220 is a 12S bus interface for receiving serial audio data output from the multichannel audio decoder 210 to a 12S bus.

The audio signal extractor 230 extracts digital audio data to be transmitted through a Bluetooth wireless communication method from the serial audio data input through the serial audio signal input unit 220.

The Bluetooth transmitter 240 receives the audio signal extracted from the audio signal extractor 230 and loads the extracted digital audio data into each Bluetooth stack to be described later through the Bluetooth module 250. ) Will be sent to the target.

At this time, the Bluetooth transmission unit 240 does not use the SCO link (see Fig. 1) of the limited bandwidth to send the existing voice data, the digital audio data of the corresponding multi-channel by using the ACL link that can transmit and receive non-voice data To send.

Here, the conventional SCO link (Synchronous Connection-Oriented link) is a link used for voice transmission between the transmission and reception, while the ACL link (Asynchronous Connection-Less link) is mainly non-voice A link used to transmit and receive burst data.

In this regard, the internal protocol configurations of the Bluetooth transmitter 240 and the Bluetooth module 250 are as follows.

The baseband of the Bluetooth stack performs a paging procedure for synchronizing transmission hopping frequencies and clocks of different devices, where Bluetooth transmits a frequency hopping spectrum in which packet data is time-divided. Because of the spreading scheme, these protocol stacks use Inquiry and Paging to synchronize the Bluetooth device's hopping frequency and clock. This baseband provides two physical access methods, an SCO link primarily responsible for voice transmission and an ACL link associated with the present invention primarily responsible for data communication.

The Link Manager Protocol of the Bluetooth stack establishes a link between Bluetooth devices. This protocol controls the generation, exchange, and check of links and encryption keys and the packet size of the baseband.

The Service Discovery Protocol (SDP) of the Bluetooth stack is a profile for identifying currently valid services, and provides an important role in providing a service for determining the use of Bluetooth in advance.

Logical link control and adaptation protocol (L2CAP) of the Bluetooth stack is a protocol located above the baseband, and is responsible for multi-communication functions, data division and combination, and group abstraction for the upper protocol stack. Provide service. L2CAP allows higher-level protocols and applications to send and receive L2CAP packet data up to 64K bytes in length.

The HCI layer and the HCI transport layer of the Bluetooth stack shown in the figure are host controller interfaces, which represent standardized interfaces for accessing and controlling the baseband, link manager and hardware included in the host controller. The protocol prescribes a procedure for accessing hardware, and the Bluetooth Universal Transport Manager manages the Bluetooth stack described above.

In this case, the audio signal is transmitted to the Bluetooth module 250 using the L2CAP and HCI protocols, which are Bluetooth protocols, and the Bluetooth transmitter 240 and the Bluetooth module 250 are connected to the USB interface. It is preferable to be connected to.

That is, in the above-described Bluetooth connection, the Bluetooth transmitter 240 and the Bluetooth module 250 of the transmitter 200 do not use the conventional synchronous SCO link when transmitting the digital audio signal of the multichannel, The L2CAP stack transmits the digital audio signal of the corresponding multi-channel to the Bluetooth module 310 and the Bluetooth receiver 320 of the receiver 300 through an asynchronous ACL link.

The receiver 300 includes a Bluetooth module 310, a Bluetooth receiver 320, a serial audio signal output unit 330, an audio processor 340, a multichannel DAC 350, a mixer, and an amplifier 360. It is composed.

In this case, the Bluetooth module 310 and the Bluetooth receiver 320 of the receiver 300 have the same configuration as the Bluetooth transmitter 240 and the Bluetooth module 250 of the transmitter 200 described above.

Here, the Bluetooth receiver 320 extracts the received multichannel digital audio data using an internal L2CAP stack.

The serial audio signal output unit 330 is a 12S bus interface for reconstructing and outputting the extracted digital audio data into serial audio data according to the 12S bus interface.

The audio processor 340 decodes the serial audio data output through the serial audio signal output unit 330 into digital audio data separated for each channel according to a multi channel using a dedicated audio DSP.

The multichannel DAC 350 and the mixer and amplifier unit 360 are multichannel processing means for converting the digital audio signal into a reproducible multichannel analog audio signal.

More specifically, the multichannel DAC 350 converts the multichannel digital audio data decoded for each channel through the audio processor 340 into an analog audio source through an internal digital analog convertor (DAC).

The mixer and amplifier unit 360 mixes each channel and amplifies a corresponding signal for each channel so that each channel can produce an appropriate home theater effect for the multichannel headphones with respect to the analog audio source converted for each channel. The multichannel output headset 400 is transferred to the multichannel output headset 400.

The wireless multi-channel audio transmission / reception method using Bluetooth according to the present invention having the above-described configuration will be described with reference to FIG. 3.

First, the optical output port 120 is inputted in the S / PDIF data format from the digital audio signal source 100 that is a multi-channel digital audio signal output device such as a DVD player, a PC sound card, a video game machine, a portable multimedia player (PMP), or the like. The multi-channel digital audio signal output through the input is received (S10).

Then, the multi-channel digital audio signal output from the signal source 100 in the S / PDIF data format is decoded through the multi-channel audio decoder 210, and 12S (the audio format of the serial audio data) is decoded. Inter-IC Sound) is converted into an audio format (S12).

Next, the serial audio data output from the multi-channel audio decoder 210 to the 12S bus is received through the serial audio signal input unit 220, and the Bluetooth wireless communication is performed on the corresponding audio data through the audio signal extractor 230. Digital audio data to be transmitted is extracted in the manner (S14).

Then, the Bluetooth transmitter 240 and the Bluetooth module 250 receiving the extracted digital audio data are connected to the piconet through the L2CAP and the HCI protocol and the internal protocol stack to receive the receiver as an asynchronous ACL link. The extracted digital audio data is transmitted at step 300 (S16).

On the receiver side, the Bluetooth module 310 and the Bluetooth receiver 320 of the receiver 300 receive the digital audio signal transmitted from the transmitter 200 via the piconet via an ACL link (S18).

Then, the Bluetooth receiver 320 extracts the digital audio data from the data received through the ACL link using an internal L2CAP stack (S20).

Next, in a state in which the extracted digital audio data is reconstructed into serial audio data for the 12S bus interface and output, the audio processor 340 separates each channel according to multiple channels using a dedicated audio DSP. The decoded digital audio data is decoded (S22).

Thereafter, the digital audio data of the multichannel decoded for each channel is converted into an analog audio source (S24), and each channel has an appropriate home theater effect on the multichannel headphones for the analog audio source converted for each channel. Mixing each channel so as to amplify and amplify the corresponding signal for each channel to transfer to the multi-channel dedicated output headset 400 (S26), it is possible to smoothly use the multi-channel audio signal through wireless Bluetooth.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited to drawing.

As described above, the wireless multi-channel audio transmission and reception system and method using Bluetooth according to the present invention transmits and receives a large amount of multi-channel audio data among digital audio data at a smooth speed in transmitting and receiving wireless audio signals through short-range Bluetooth communication. This allows the multichannel audio device to be a Bluetooth device.

In particular, the digital audio data of the corresponding multi-channel is transmitted by using the ACL link that can transmit / receive non-voice data without using the SCO link having a limited bandwidth for transmitting existing voice data. It also has the effect of securing bandwidth and guaranteeing an improved audio signal transmission rate compared to the ACL link.

Claims (8)

In a wireless multi-channel audio transmission and reception system using Bluetooth for transmitting and receiving audio signals through a Bluetooth interface, A multichannel audio decoder for receiving a multichannel digital audio signal output from a signal source and decoding the serial audio data; An audio signal extraction unit for extracting digital audio data for transmission from serial audio data transmitted from the multichannel audio decoder; A Bluetooth transmitter and module configured to receive digital audio data for transmission extracted by the audio signal extractor and to transmit the extracted data to asynchronous ACL link using a respective L2CAP stack; A Bluetooth receiver and module for receiving data transmitted from the Bluetooth transmitter and module and extracting digital audio data using an internal L2CAP stack; A serial audio signal output unit configured to receive the extracted digital audio data and to reconstruct and output the serial audio data; An audio processor which decodes serial audio data output through the serial audio signal output unit into digital audio data separated for each channel; And Multi-channel processing means for receiving the decoded digital audio data separated for each channel, converting the digital audio data into an analog audio source, mixing each channel, and outputting the mixed audio channel to an audio output device; Wireless multi-channel audio transmission and reception system using Bluetooth, comprising a. The method of claim 1, The digital audio signal of a signal source input to the multichannel audio decoder is a S / PDIF (Sony / Philips Digital Interface) data format capable of processing a multichannel digital audio signal. . The method of claim 2, The multi-channel audio decoder receives a digital audio signal by S / PDIF and analyzes the frequency thereof. The multi-channel audio decoder analyzes the type and the number of channels of the audio signal based on the analyzed frequency. A wireless multi-channel audio transmission / reception system using Bluetooth, characterized in that for outputting in 12S (Inter-IC Sound) audio format which is an audio format of serial audio data. The method of claim 3, wherein The serial audio signal output unit outputs digital audio data received and transmitted by the Bluetooth receiver and the module in a 12S (Inter-IC Sound) audio format, which is an audio format of serial audio data. Audio transmission and reception system. In the wireless multi-channel audio transmission and reception method using Bluetooth for transmitting and receiving audio signals between the transmitting device and the receiving device through a Bluetooth interface, (a) receiving a multi-channel digital audio signal output from a digital signal source through a transmitting device, decoding the serial audio data, and extracting digital audio data for transmission from the decoded serial audio data; (b) connecting the transmitter and the receiver with an asynchronous ACL link and transmitting the extracted digital audio data to an asynchronous ACL link using an L2CAP stack; (c) receiving data transmitted from the transmitter through a receiver, extracting digital audio data using an internal L2CAP stack of the receiver, and reconstructing the extracted digital audio data into serial audio data. step; And (d) decoding the serial audio data into digital audio data separated for each channel, converting the decoded digital audio data into an analog audio source, mixing each channel, and outputting the mixed audio data to an audio output device; Wireless multi-channel audio transmission and reception method using a Bluetooth comprising a. The method of claim 5, In the step (a), the digital audio signal input from the digital signal source is a wireless multi-channel audio using Bluetooth, characterized in that the S / PDIF (Sony / Philips Digital Interface) data format capable of processing the multi-channel digital audio signal How to send and receive. The method of claim 6, In the step (a), the digital audio signal is received from the digital signal source by S / PDIF and the frequency is analyzed. The type and the number of channels are analyzed based on the analyzed frequency and separated according to the number of channels. And outputting the digital audio signal in a 12S (Inter-IC Sound) audio format, which is an audio format of serial audio data. The method of claim 7, wherein The step (c) further includes converting the digital audio data extracted using the internal L2CAP stack of the receiver into an 12-s (Inter-IC Sound) audio format, which is an audio format of serial audio data. Wireless multi-channel audio transmission and reception method using a Bluetooth.

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