WO2008067388A1 - Gestion de tampon adaptative pour un système de connectivité sans fil - Google Patents

Gestion de tampon adaptative pour un système de connectivité sans fil Download PDF

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Publication number
WO2008067388A1
WO2008067388A1 PCT/US2007/085775 US2007085775W WO2008067388A1 WO 2008067388 A1 WO2008067388 A1 WO 2008067388A1 US 2007085775 W US2007085775 W US 2007085775W WO 2008067388 A1 WO2008067388 A1 WO 2008067388A1
Authority
WO
WIPO (PCT)
Prior art keywords
audio
buffering device
buffer circuit
data
buffer
Prior art date
Application number
PCT/US2007/085775
Other languages
English (en)
Inventor
David T. Dembinski
Prabin Pradhan
Timothy J. Schnobel
Original Assignee
Johnson Controls Technology Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Johnson Controls Technology Company filed Critical Johnson Controls Technology Company
Publication of WO2008067388A1 publication Critical patent/WO2008067388A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/24—Traffic characterised by specific attributes, e.g. priority or QoS
    • H04L47/2416—Real-time traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/25—Flow control; Congestion control with rate being modified by the source upon detecting a change of network conditions
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/29—Flow control; Congestion control using a combination of thresholds
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/30—Flow control; Congestion control in combination with information about buffer occupancy at either end or at transit nodes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control

Definitions

  • Bandwidth utilization limitations can occur when attempting to connect a device in a shared bandwidth application.
  • shared bandwidth applications i.e., Wi-Fi, Bluetooth, etc.
  • An exemplary shared bandwidth application is Bluetooth.
  • a Bluetooth-enabled device which is streaming audio from another Bluetooth-enabled device will need the audio data to be buffered.
  • a hands-free module HFM
  • it may search and connect simultaneously to a Bluetooth-enabled phone for telephony services and to a Bluetooth-enabled audio device for streaming audio.
  • Attempting to connect to a Bluetooth device may require a high Bluetooth bandwidth, therefore, the HFM may not be able to connect to the phone for telephony services while streaming audio from the audio device.
  • inconvenience may be observed in a shared bandwidth application.
  • inconvenience may be observed in a Bluetooth application as follows:
  • the connection may not be able to be re-established until the audio is paused. During this time, the user may not be able to accept incoming calls or make outgoing calls from the HFM;
  • One embodiment of the disclosure relates to an audio buffering device including an application interface, an audio player interface, a buffer circuit, and a control circuit.
  • the control circuit increases a data rate transfer to the buffer circuit based on a streaming data status.
  • an audio buffering device including an application interface, an audio player interface, a buffer circuit, a control circuit, and a silence detection algorithm, such as, a zero crossing detection circuit.
  • the zero crossing detection circuit detects a track change and decreases an audio data based on a detected track change.
  • the control circuit increases a data rate transfer to the buffer circuit based on a streaming data status.
  • an audio buffering device including an application interface, an audio player interface, a buffer circuit, a control circuit, and a silence detection algorithm, such as, a zero crossing detection circuit.
  • the zero crossing detection circuit detects a track change and is configured to increase or decrease an audio data based on a detected track change.
  • the control circuit increases a data rate transfer to the buffer circuit based on a streaming data status and the control circuit transfers data to the buffer circuit based on a buffer circuit capacity.
  • the audio buffering device further includes a transport layer in communication with an application based on the buffer circuit reaching a first predetermined value and wherein a polling rate for streaming data is modified based on at least one of an application status, the buffer circuit reaching the first predetermined value, and the buffer circuit reaching a second predetermined value.
  • FIG. 1 is a schematic diagram illustrating a system for connecting an audio device with a hands-free module, according to one exemplary embodiment.
  • FIG. 2 is a process flow diagram illustrating method for managing an audio buffer of the system of FIG. 1, according to an exemplary embodiment.
  • FIG. 3 is a schematic diagram illustrating page scan time periods in the system of FIG. 1, according to an exemplary embodiment.
  • an adaptively managed data buffer will be used to provide a continuous stream of data from one device source to the hands-free module. This will prevent the end user from noticing a data gap due to bandwidth sharing by multiple bandwidth sharing devices.
  • the buffer will increase or decrease in size as the baseband utilization requirements increase or decrease.
  • shared bandwidth applications e.g., Bluetooth
  • the shared bandwidth applications can be wireless or wired applications.
  • Bluetooth baseband bandwidth is a limited resource, and in scatternet applications, high bandwidth use can cause one or more of the shared bandwidth devices to have unreliable connections due to bandwidth starvation.
  • an adaptive audio buffering strategy may allow the hands-free module (HFM) to establish a Bluetooth or other wireless connection with one wireless device while streaming data with another wireless device to prevent bandwidth starvation.
  • the buffering strategy may allow the HFM to connect to a phone while streaming audio.
  • software for the Bluetooth application and the streaming audio player application in the HFM may be modified.
  • a system 10 that includes an audio path in a HFM 12 capable of playing streaming audio.
  • a Bluetooth application software 14 interfaces with a Bluetooth hardware 16 for communication with an audio device 18.
  • the interfaces is through baseband communication via a universal asynchronous receiver/transmitter (UART).
  • Bluetooth profile functionality and device management may be implemented in Bluetooth software 14.
  • Bluetooth software 14 may poll encoded audio data from audio device 18, decode the audio data, and store the data in an audio buffer 20.
  • Device 18 can be embodied as a cellular phone, wireless phone, iPod, MPG player, laptop, PDA, smartphone, or other device that can communicate audio data.
  • Bluetooth application software 22 may allocate bandwidth for different services, based on its state, for simultaneous connection to multiple devices, according to an exemplary embodiment. This may allow HFM 12 to provide a high quality of service while multiple devices are connected. Table I shows an exemplary bandwidth allocation for an audio service and a phone service.
  • the customer application software (not shown in Figure. 1 ) may stop searching for an audio device.
  • the customer application software (not shown in Figure. 1 ) may stop searching for a phone.
  • a streaming audio player software 24 may be configured to read pulse-code modulation (PCM) data from audio buffer 20 and play it through an audio driver 26 to an audio Codec 28, according to an exemplary embodiment.
  • PCM pulse-code modulation
  • streaming audio player software 24 may read between 1 and 1,048,576 bytes from audio buffer 20 at a time and play stereo audio at a frequency of between 16kHz and 48kHz.
  • streaming audio player software 24 may read between 1 and 1 ,024 bytes from audio buffer 20 at a time and play stereo audio at a frequency of between 44kHz and 48kHz.
  • streaming audio player software 24 may read 882 bytes from audio buffer 20 at a time at a frequency of 48KHz.
  • the Bluetooth bandwidth may not allow HFM 12 to connect to a phone while simultaneously streaming audio.
  • the connection process, or paging, to the remote device may consume all the Bluetooth bandwidth. Since the current system may allocate a relatively high Bluetooth bandwidth during streaming audio, the system may not have sufficient bandwidth to page the phone. In order to successfully page the phone while streaming audio, the allocated bandwidth for the audio service may be reduced. Once the bandwidth is reduced, the system may not be able to poll sufficient audio data at the rate of audio being played, thus creating a buffer under-run condition and distorting audio.
  • the Bluetooth application may increase the polling rate to retrieve as much audio data as possible from the remote device to increase audio buffer 20 in HFM 12.
  • the streaming audio player software 24 may increase audio buffer 20 by slowing down the playback and adding silence when the audio file changes. Once audio buffer 20 reaches the maximum page size, it decreases the bandwidth and performs a page operation on the phone. During this time, the Bluetooth application may not be able to poll any audio data, however streaming audio player software 24 may play buffered audio data. This strategy may reduce audio disruption during playback. If the phone is not connected and page timeout occurs, audio buffer 20 will be increased by the streaming audio player and the Bluetooth application by increasing the polling rate. Once the phone is connected, audio buffer 20 will be managed normally by setting the nominal Bluetooth bandwidth as shown in Table I, and playing the audio at a normal frequency.
  • HFM 12 may be able to re-connect to the phone without disrupting streaming audio. This may allow the user to make a phone call or receive an incoming call from HFM 12 while streaming audio. Additionally, if the user starts streaming audio before the phone is connected to HFM 12, the Bluetooth connection to the phone may be able to establish without disrupting the audio. The user may then be able to accept an incoming call and may be able to make an outging call from HFM 12. Further, the user may not need to take action to compensate for a Bluetooth bandwidth constraint that may cause difficulties connecting to the phone while streaming audio.
  • the system starts with a request to connect to a phone (step 100).
  • the system determines whether there is audio streaming from a music device (step 102). If there is no audio streaming from a music device, then the system operates by following the normal connection process (step 118). If there is audio streaming from a music device, then the system increases audio buffer 20 by increasing Bluetooth polling rate and using DSP technique in streaming audio player software 24 (step 104).
  • the system determines whether audio buffer 20 is at maximum capacity (step 106). If audio buffer 20 is not at maximum capacity, then the system moves back to step 104 (step 106). If the system determines that audio buffer 20 is at maximum capacity, then the system decreases Bluetooth bandwidth for music service (step 108).
  • the system then in step 110 pages phone or page scan for a predetermined time period (i.e., 1 microsecond, 10 microseconds, 100 microseconds, 1 second, 10 seconds, 60 seconds, etc.).
  • the system determines whether the phone connection is completed (step 112). If the phone connection is completed, then the system sets normal Bluetooth bandwidth and runs streaming audio player software 24 (step 116). If the phone connection is not completed, then the system increases Bluetooth bandwidth for music service (step 114) and moves back to step 104.
  • the phone and music device can be any device that is employed in a shared bandwidth application.
  • a page synchronization timeout 40 may be a factor for end-to-end delay, audio buffer 20 size, and/or connection time.
  • HFM 12 may be set to about 5 seconds for page synchronization timeout 40. If a page scan window 42 is equal to a page scan interval 44 then the system continues scanning. According to various exemplary embodiments, page scan interval 44 may be between 0 and 10 seconds. According to another embodiment, page scan interval 44 may be 1.28 seconds.
  • One page scan interval 44 may be sufficient to page from the master Bluetooth address, however, due to page hops that depend on the Bluetooth native clock and the slave Bluetooth address, the system may use more than one page scan interval 44.
  • Table II shows a range of page synchronization operations based on page scan intervals 44, according to one exemplary embodiment.
  • page synchronization timeout 40 may be set to about 5 seconds to allow between 3 and 4 operations to achieve synchronized paging. If the page synchronization timeout 40 is changed to about 3.84 seconds, the system may allow between 2 and 3 operations to synchronize the paging. Audio buffer 20 size may be dependent on page synchronization timeout 40 because audio buffer 20 may hold enough audio data to play audio until page synchronization timeout 40 occurs. The following exemplary calculation may be done in a shared bandwidth system (i.e., Bluetooth) with a 5 second page synchronization timeout 40.
  • a shared bandwidth system i.e., Bluetooth
  • audio buffer 20 may be:
  • Audio buffer 20 may be protected for over-run condition.
  • One second of audio data may be sufficient for this over-run condition:
  • Audio Buffer Size Max. Buffer Required for Page Timeout + Buffer for over-run condition
  • the following exemplary calculation may be done for page synchronization timeout 40 of 3.84 seconds.
  • the shared bandwidth application i.e., Bluetooth
  • Table III shows the size of audio buffer 20 that may be filled prior to paging remote devices.
  • SBC sub-band control
  • L2CAP Logical Link Control and Adaptation Protocol
  • CP Content Protection Header
  • SBC Frame 115 bytes
  • Each SBC frame contains an MPLH
  • Max. decoder supported bit rate -> 512 Kbits/sec. -> 64 Kbytes/sec. Total number of SBC frames in 1 second without any header:
  • the following table illustrates various qualities of the system when L2CAP is not performing fragmentation.
  • the following table illustrates various qualities of the system when L2CAP is performing fragmentation.
  • the decoder of the audio sink may support multiple bitpool values that do not result in the system exceeding the maximum bit rate.
  • this profile may limit the available maximum bit rate to 320kb/s for mono and 512kb/s for two-channel modes.
  • the maximum bandwidth is 345 Kbits/sec.
  • ACL packets in the baseband specification have a maximum asymmetric bandwidth of 723.2 Kbits/sec.
  • the audio data in audio buffer 20 may be increased in order to let the shared bandwidth application (i.e., Bluetooth) page a phone without disrupting audio quality. Similarly, the audio data in audio buffer 20 may be decreased once the connection to the phone is established in order to decrease end-to-end delay.
  • the shared bandwidth application i.e., Bluetooth
  • the shared bandwidth system may use a zero- crossing silence detection algorithm to detect silence during track change and add more silence to increase the audio data in audio buffer 20. Similarly, the shared bandwidth system may remove silence during a track change from the audio playback to decrease the audio data in audio buffer 20.
  • the system may decrease the playback frequency a few kHz less than the streaming frequency to increase the audio data in audio buffer 20. Similarly, the system may increase the playback frequency a few kHz more than the streaming frequency to decrease the audio data in audio buffer 20.
  • the following example calculation shows a duration used to increase audio size in audio buffer 20 for a 5 second page synchronization timeout 40 while streaming at 48kHz, and playback at 46kHz.
  • Table VIII illustrates further examples of time intervals it may take to increase audio buffer 20 size for paging.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un dispositif de tamponnement audio comprenant une interface d'application, une interface de lecteur audio, un circuit tampon et un circuit de commande. Le circuit de commande augmente un transfert de débit de données vers le circuit tampon d'après un état de données de transmission en continu.
PCT/US2007/085775 2006-11-29 2007-11-28 Gestion de tampon adaptative pour un système de connectivité sans fil WO2008067388A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US86147906P 2006-11-29 2006-11-29
US60/861,479 2006-11-29

Publications (1)

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WO2008067388A1 true WO2008067388A1 (fr) 2008-06-05

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8611337B2 (en) 2009-03-31 2013-12-17 Adobe Systems Incorporated Adaptive subscriber buffering policy with persistent delay detection for live audio streams
US20210076435A1 (en) * 2019-09-11 2021-03-11 Samsung Electronics Co., Ltd. Electronic device for receiving data packet in bluetooth network environment and method thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1370101A1 (fr) * 2002-06-04 2003-12-10 Telefonaktiebolaget L M Ericsson (Publ) Méthode pour traiter des connexions multiples dans un terminal
EP1450514A1 (fr) * 2003-02-18 2004-08-25 Matsushita Electric Industrial Co., Ltd. Contrôle de débit par un serveur dans un environnement multimédia de transmission continue de données
EP1469659A1 (fr) * 2003-04-16 2004-10-20 Nokia Corporation Un terminal radio à courte distance pour les flux de données et pour des services en temps réel

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1370101A1 (fr) * 2002-06-04 2003-12-10 Telefonaktiebolaget L M Ericsson (Publ) Méthode pour traiter des connexions multiples dans un terminal
EP1450514A1 (fr) * 2003-02-18 2004-08-25 Matsushita Electric Industrial Co., Ltd. Contrôle de débit par un serveur dans un environnement multimédia de transmission continue de données
EP1469659A1 (fr) * 2003-04-16 2004-10-20 Nokia Corporation Un terminal radio à courte distance pour les flux de données et pour des services en temps réel

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8611337B2 (en) 2009-03-31 2013-12-17 Adobe Systems Incorporated Adaptive subscriber buffering policy with persistent delay detection for live audio streams
US20210076435A1 (en) * 2019-09-11 2021-03-11 Samsung Electronics Co., Ltd. Electronic device for receiving data packet in bluetooth network environment and method thereof
US11582815B2 (en) * 2019-09-11 2023-02-14 Samsung Electronics Co., Ltd. Electronic device for receiving data packet in Bluetooth network environment and method thereof

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