WO2008141341A9 - Method and apparatus for wireless hdmi clock regeneration - Google Patents

Method and apparatus for wireless hdmi clock regeneration Download PDF

Info

Publication number
WO2008141341A9
WO2008141341A9 PCT/US2008/066512 US2008066512W WO2008141341A9 WO 2008141341 A9 WO2008141341 A9 WO 2008141341A9 US 2008066512 W US2008066512 W US 2008066512W WO 2008141341 A9 WO2008141341 A9 WO 2008141341A9
Authority
WO
WIPO (PCT)
Prior art keywords
frames
clock
source clock
clock frames
source
Prior art date
Application number
PCT/US2008/066512
Other languages
French (fr)
Other versions
WO2008141341A1 (en
Inventor
Sai C Manapragada
Alvin Dale Kluesing
Original Assignee
Picongen Wireless Inc
Sai C Manapragada
Alvin Dale Kluesing
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 Picongen Wireless Inc, Sai C Manapragada, Alvin Dale Kluesing filed Critical Picongen Wireless Inc
Priority to EP08770669.3A priority Critical patent/EP2183873A4/en
Publication of WO2008141341A1 publication Critical patent/WO2008141341A1/en
Publication of WO2008141341A9 publication Critical patent/WO2008141341A9/en

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/23Processing of content or additional data; Elementary server operations; Server middleware
    • H04N21/242Synchronization processes, e.g. processing of PCR [Program Clock References]
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/28Timers or timing mechanisms used in protocols
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/43Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
    • H04N21/4302Content synchronisation processes, e.g. decoder synchronisation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/80Responding to QoS
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00Arrangements for synchronising receiver with transmitter
    • H04L7/0008Synchronisation information channels, e.g. clock distribution lines

Definitions

  • the present application relates to multi-media networks, more particularly, to wirelessly transmission of a clock line for multimedia data distribution.
  • the content of the distribution includes, but not limited to, high-definition video, digital sound, satellite TV, cable TV, high speed data, games, etc.
  • HD high definition
  • the High-Definition Multimedia Interface (HDMI) specification allows transfer of uncompressed HD signals between devices via a cable. While consumer electronics makers are beginning to offer HDMI-compatible equipment, there is not yet a suitable wireless (e.g., radio frequency) technology that is capable of transmitting uncompressed HD video signals.
  • Wi-Fi enabled device such as a PC, game console, cell phone, MP3 player or a PGA can connect to the internet when within range of a wireless network that is connected to the Internet.
  • Wi-Fi hotspot (Access Point) can be as little as a single room with wireless-opaque walls or as much as many square miles covered by overlapping access points.
  • Routers which incorporate a DSL or cable modem and a Wi-Fi access point are often used in homes and other premises, and provide Internet access and inter-networking to all devices connected via wireless or by cable into them. Devices supporting Wi-Fi can also be connected in ad-hoc mode for client-to- client connections without a router.
  • Wi-Fi devices use unlicensed spectrum to provide access to a network, ameliorating the trouble of obtaining FCC license.
  • Wi-Fi allows LANs to be deployed without cabling for client devices, dramatically reducing the costs of network deployment and expansion.
  • a current typical Wi-Fi adapter operates at a maximum raw data rate of 54
  • the current Wi-Fi system with 54 Mbit/s capacity, is powerless to transmit high definition video, audio and other multimedia.
  • Band technology can offer up to 5Gbit/s, its range usually is within 10 meters, and often is Line of Sight.
  • HD video is first compressed before transmitting to the wireless medium. Compression of the HD video is attractive because the overall required communication bandwidth and power can be significantly reduced, relative to transmission of the original, uncompressed video. However, with each compression and subsequent decompression of the video, some video information can be lost and the picture quality is degraded.
  • Wireless transmission of HDMI video/audio is key to operate a high quality home entertainment network.
  • Conventional HDMI cable contains multiple wired connections for data transfer including 1 wired line for CLOCK.
  • This wire provides the source HDMI clock from a source, such as an HD DVD player to the destination HDMI clock, such as an HDMI plasma TV. This signal is required to synchronize the data for transfer and HDMI encryption.
  • the HDMI cable connected between the source (e. g. DVD player) and the destination (e. g. TV) provides this CLOCK line.
  • the CLOCK line is missing.
  • data are transmitted as data packets.
  • the access nodes obtain the data through a common IP multicast or broadcast group over an IP multicast network.
  • Packets for the multicast or broadcast may arrive at the access nodes with differing delays due to non-synchronous nature of IP multicast or broadcast forwarding. Packets may also be non-synchronous because packets may be lost along the multicast forwarding path.
  • This application discloses a novel system, device, and methods for providing a wireless clock line.
  • an HDMI source clock is transmitted to Wireless Clock Transmitter (WCT) which transmits information regarding the source clock in relation to a reference radio frequency such as Wi-Fi Beacon or a GPS signal.
  • WCT Wireless Clock Transmitter
  • a Wireless Clock Receiver (WCR) receives the transmitted clock reference and the information about the source clock and sends a replicated source Clock signal to a HDMI sink.
  • WCT and WCR periodically synchronize and re-synchronize between each other at request or automatically.
  • the request for synchronization can come from the Wireless Clock Receiver.
  • the system also does automatic re- synchronization periodically.
  • Wi-Fi Beacon is used as wireless reference; in another embodiment, a local GPS (Global Positioning System) is used as a wireless reference.
  • GPS Global Positioning System
  • the smallest time difference between the source clock frame and the wireless reference clock frame is calculated and transmitted to a receiver, and such difference is used to estimate source clock frame on the receiver.
  • Subsequent Phase Tracking is done by using Phase Lock Loop, and is used to replicate the source clock frame in the receiver's local clock system.
  • the estimated source clock frame is replicated by taking into account the initial phase difference and is replicated at the starting time of the next local clock phase.
  • FIG. 1 schematically shows an example of Picon macronetwork.
  • FIG. 2 depicts an example architecture of a Picon wireless multimedia gateway.
  • FIG. 3 depicts an example architecture of a Picon wireless multimedia adapter.
  • FIG. 4 depicts an example clock channel in a multi-streaming transmitting unit in a Picon system.
  • FIG. 5 depicts an example clock channel in a multi-streaming receiving unit in a Picon system.
  • FIG. 6 shows an example functional process of a wireless clock control system.
  • FIG. 7 shows a working process of a wireless clock control transmitter.
  • FIG. 8 shows a working process of a wireless clock control receiver.
  • FIG. 9 shows an operation process for transceiving a wireless clock control to a sink using Wi-Fi beacon clock frame.
  • FIG. 10 shows an operation process for transceiving a wireless clock control to a sink using local GPS clock frame.
  • High Definition (HD) signals are typically transmitted from one system to another using cables carrying DVI (Digital Video Interface) or HDMI (High Definition Multimedia Interface) signals.
  • DVI/HDMI signals are conveyed using a signaling scheme known as Transition Minimized Differential Signaling (TMDS).
  • TMDS Transition Minimized Differential Signaling
  • video, audio, and control data are carried as a series of 24-bit words on three TMDS data channels with a separate TMDS channel for carrying clock information.
  • DVI/HDMI systems may include a separate bi-directional channel known as the Display Data Channel (DDC) for exchanging configuration and status information between a source and a sink, including information needed in support of High-Bandwidth Digital Content Protection (HDCP) encryption and decryption.
  • DDC Display Data Channel
  • HDMI an optional Consumer Electronic Control (CEC) protocol provides high-level control functions between audiovisual products.
  • CEC Consumer Electronic Control
  • the Picon wireless home network comprises Picon Media Server and Picon Receiver that can seamlessly and securely integrate into the conventional audio-video cable system and provides about 10x improvement in data throughput over standard Wi-Fi technology, thus enables consumers to stream high quality wireless video, digital audio and high speed data applications across multiple rooms in home and in office without the stress of cabling.
  • the Picon system also provides an architecture to wirelessly transmit clock channels for data synchronization and for seamless integration into the conventional system.
  • a Picon system is compatible with existing wireless technology and High Definition Multimedia Interface (HDMI), IEEE 802.11, Multiple-in Multiple out (MIMO), standard Wi-Fi physical (PHY) and Media Access Control (MAC) layer, and existing IP protocols, extremely high bandwidth applications such as Voice IP (VOIP), streaming audio and video content (including high definition), multicast applications, and also supports convergent networks, and ad hoc networks.
  • HDMI High Definition Multimedia Interface
  • MIMO Multiple-in Multiple out
  • PHY Wi-Fi physical
  • MAC Media Access Control
  • IP protocols extremely high bandwidth applications
  • VOIP Voice IP
  • streaming audio and video content including high definition
  • multicast applications and also supports convergent networks, and ad hoc networks.
  • video, audio, and related information data signals are digitally encoded into a packetized data stream using a number of algorithms, including error protection and correction.
  • a micro-controller may be included to control the overall operation, including selection of parameters, the set-up and control of components, channel selection, viewer access to different programming packages, blocking certain channels, packet loss prevention and other functions.
  • the compression and de-compression of packetized data streams may be accomplished according to the Motion Picture Expert Group (MPEG) various standards and HDMI standards and specifications.
  • MPEG Motion Picture Expert Group
  • FIG. 1 is a network diagram illustrating an example wireless communication network 100 according to an embodiment of the present disclosure.
  • the wireless network 100 comprises a plurality of devices including device 111, 113, 115, 117, 119, 121, 123, 125, 127, 129 etc.
  • Each of the devices can be any of a variety of multimedia and/or wireless devices, including a DVD player, digital audio systems, analog or digital TV, camcorder, digital camera, printer, scanner, fax machine, copy machine, graphics processor, cell phone, personal digital assistant ("PDA”), personal computer (“PC”), laptop computer, PC card, special purpose equipment, access point, router, switch, base station controller, game machine, Wi-Fi phone, security camera, set top box, GPS, or any combination of these and other devices configured to process and handle large amount of data.
  • the transmission of data from the access nodes to the mobile stations can be over one of a variety of wireless technologies, such as IEEE 802.11, 802.16, CDMA, OFDM, UMTS, HSDPA, etc.
  • the networks can include CDMA, GSM, CDMA2000, W-CDMA, UMTS, WiFi, WiMAX and other known and developing networks.
  • the access nodes conform to IEEE 802.11, 802.16 and WiMAX standards.
  • Picon media server 102 and receiver 104 these media display devices, regardless of whether they were originally capable of wireless communication, will gain the capacity to communicate to other devices in the network wirelessly. These devices become not only the data receivers, but also data providers, when the communication is configured to be bi-directional. Other data sources can, as indicated by such as 101, 103, 105, 107, 109, be for any of a variety of cable TV, satellite system, gaming stations, broadband Internet, IPTVs etc., provided by outside service providers, including audio, video data, or application data or the combination thereof.
  • the communication with these data sources can be configured to be either uni-directional or bidirectional, that any of the above mentioned devices can send data to those service systems through the Picon media server/receiver wirelessly.
  • the communication between the Picon media server and receiver may be configured to be bidirectional as well.
  • High rate digital data come into the network through wire or satellite dish, via conventional connections such as satellite set-top box 101, gaming stations 103, cable TV set-top box 105, DSL modem 107, IPTV set-top box 109 etc.
  • the high rate digital data are transmitted to Picon Media Server 102 through wire for data processing into lower rate digital data stream. Processed data are then wirelessly transmitted to Picon Receiver 104 which is connected with individual display devices, such as, devices 111, 113, 115, 117, 119, 121, 123, 125, 127, 129.
  • Picon Receiver 104 upon receiving the wirelessly transmitted lower rate data stream, recovers and restores the lower rate data streams into the original high rate data stream and then sends them to the respective corresponding play or display device.
  • the wireless transmission may be based on Wi-Fi protocol (IEEE 802.11 or other protocol transmission protocols, such as Third Generation Partnership Project (3 GPP) 2G and 3 G Code Division Multiple Access (CDMA) technologies, using IP or IP secure protocols.
  • Wi-Fi protocol IEEE 802.11
  • 3 GPP Third Generation Partnership Project
  • CDMA Code Division Multiple Access
  • the network 100 could be any of a variety of network types and topologies and employ any of a variety of types of protocols.
  • the illustrated embodiment will be described as an IEEE 802.11 compliant.
  • the high data rate content streams from one or more data sources can either be encrypted or unencrypted; compressed or uncompressed.
  • the Picon media server 102 can include other switches and routers to direct the input data steams to the correct processing port.
  • FIG. 2 shows an example of transmitting of a wireless clock line in a Picon Wireless Multimedia Gateway.
  • the PHY layer of a Picon transmitter includes one or more Wireless Multimedia Gateways that comprises both multi- streaming and multi-channelling mechanism.
  • Multi-streaming mechanism comprises plurality of parallel Wi-Fi like multiplexing units which splits a single datastream into plurality of low rate (LR) bitstreams and distributes them among plurality of channels.
  • the splitting of the original high rate data stream 201 for example of a high definition video, can be implemented using the Multiple-input and multiple-output (MIMO) technology as specified in IEEE 802. Hn.
  • MIMO Multiple-input and multiple-output
  • each data type is processed by data-type specific processing unit, such as processing unit for DDC/CEC processing, composite video processing, component video processing, S-video processing, data/VoIP processing, etc.; and each of the sub-streams can be further processed in parallel in a processing unit that formats the sub-streams into packets with header information for the receiver(s) and be transmitted through one or more antennas in parallel.
  • data-type specific processing unit such as processing unit for DDC/CEC processing, composite video processing, component video processing, S-video processing, data/VoIP processing, etc.
  • each of the sub-streams can be further processed in parallel in a processing unit that formats the sub-streams into packets with header information for the receiver(s) and be transmitted through one or more antennas in parallel.
  • the number of antennas and the use of a specific antenna may be dynamically controlled by a controlling module that disperses, prioritizes, and schedules the transmission of each sub-stream.
  • a wireless clock line is transmitted as 203 for periodical data synchronization.
  • Figure 3 shows an example of receiving of a clock line in a Picon Wireless
  • the PHY layer of a Picon receiver includes one or more
  • Wireless Multimedia Adapters that comprises multiple parallel Wi-Fi adapter-like units 301 which can further have more than two low-rate receiving channels, each of which are linked to one or multiple antennas to receive data packets originally transmitted from HDMI source or other high data rate sources, and receiving channels for ordinarily compressed data.
  • Each of the received sub-streams of packets is further processed in a processing unit that de-formats the packets and checks for errors based on the header information.
  • Such sub-streams of packets may be further congregated in a multiplex converter to be outputted at high data rate (301), or can be outputted to the sink at a modified or a similar or the same data rate (305) as that of the original data streams.
  • a wireless clock line is received on a channel separate from other channels or on the same channels as the data channels and are processed and separately sent to a destination (303).
  • the Pico receiver can connect to devices using various external or internal interconnects such as PCI, miniPCI, USB, Cardbus and PC Card, or cable or digital TV connectors.
  • the output data of a Picon receiver can be directly sent to a display device.
  • the output digital data may first be converted into analog signal by a digital to analog converter before sending to a display device.
  • the application layer of the Picon transmitter includes a pre-processing module and a control module.
  • the pre-processing module can perform pre-processing of the audio/video such as partitioning of encrypted and compressed data.
  • the control module provides a standard way to exchange data stream information. Before a connection begins, the control module negotiates the data formats to be used, and when the need for the connection is completed, the control commands are used to stop the connection.
  • the transmission and receiving of the wireless signals are controlled by the control module which dynamically allocates channels based on performance statistics. In one embodiment, it monitors and analyzes the performance of each channel and allocates the channels dynamically based on their performances as well as the configuration criteria. For example, if one of the channels shows degradation in performance, that channel will be replaced with a more robust channel to avoid further packet losses. This way, the packets are first stored in a frame buffer and they are scheduled and classified dynamically before they are transmitted.
  • the control module dynamically maps communication channels and timeslots in a network so that multiple channels can be reused simultaneously throughout the network during the same timeslot in a fashion that does not create collisions.
  • the Picon media server serving as a central server first determines the network topology of its wireless communication network in order to identify its client nodes or client devices and the discrete link a node or client has. Timeslots for transmission of packets between server and a particular node device are then identified and a separate channel is assigned. The various timeslots and communication channels are dynamically mapped across the network to maximize throughput and then queued up packets are transmitted over the various channels during the various timeslots in accordance with the dynamically changing mapping.
  • the control module directs the data stream to the correct processing module 400 for multi-plexing and multi- streaming.
  • a single input datastream is split into plurality of sub-streams (409) by distributing the datastream on plurality of parallel processing units, which are further processed and packed for proper transmission (units 401 and 403), and are transmitted by application layer and PHY layer via multiple-channels.
  • a wireless source clock and reference are processed and transmitted (411 and 413).
  • the Picon receiver 500 receives the wireless transmitted digital signals 509 from the transmitter by multiple antennas and channels 503 and conducts the reverse-processing to re-assemble signals received through its multiple channels to a single stream shown as 515 and to the original format or according to the configuration by processing unit 505 and multiplex unit 507.
  • the mechanism of packet loss prevention is applied by dynamic channel assignment during the transmission to improve performance and efficiency.
  • channel X and antenna 511 are dedicated to receive the wirelessly transmitted source clock and reference clock information which are further processed and synchronized before being sent to a destination sink (513).
  • One embodiment of the structure of a Picon processing layer can further contain an add/drop multiplexer module which dynamically communicates with the FHY layer of fiber backhaul and the control unit and router unit; the control unit communicates with multiplexer, router/buffer/firewall/QoS and also the transceivers which includes encryption processor, Wi-Fi like chipset and set of radio frequency components and antennas.
  • an add/drop multiplexer module which dynamically communicates with the FHY layer of fiber backhaul and the control unit and router unit; the control unit communicates with multiplexer, router/buffer/firewall/QoS and also the transceivers which includes encryption processor, Wi-Fi like chipset and set of radio frequency components and antennas.
  • Transition Minimized Differential Signaling (TMDS) protocol can be used for signal integration and congregation of the packets.
  • video, audio, and control data are carried as a series of 24-bit words on three TMDS data channels with a separate TMDS channel for carrying clock information.
  • DVI/HDMI systems may include a separate bi-directional channel known as the Display Data Channel (DDC) for exchanging configuration and status information between a source and a sink, including information needed in support of High-Bandwidth Digital Content Protection (HDCP) encryption and decryption.
  • HDMI an optional Consumer Electronic Control (CEC) protocol provides high-level control functions between audiovisual products.
  • the source HDMI clock is first obtained from a HDMI source, for example, a DVD player, by the transmitter.
  • the transmitter then acts as a "proxy” for the destination, for example, a TV. So as far as the DVD player is concerned, it “thinks” it is indeed connected to the TV.
  • the receiver acts as the "proxy” for the source (DVD player). So as far as the TV is concerned, it “thinks” it is connected to the DVD player. So, the CLOCK information is obtained from the DVD player by the transmitter, and the TV can obtain the CLOCK information from the receiver.
  • a wireless host periodically transmits a beacon frame over one or more radio frequency (RF) channels.
  • Each beacon frame provides information about the host, including a service set identifier to identify a specific wireless network, a carrier frequency, and the beacon interval, which specifies the amount of time between beacon transmissions.
  • a wireless device that receives a beacon frame can use the information in the beacon frame to determine whether to associate with the host.
  • Figure 6 depicts the general process for transmitting a CLOCK reference.
  • An HDMI source clock 602 is transmitted (step 601) to Wireless Clock Transmitter (WCT) 604, which transmits information regarding the source clock in relation to a reference radio frequency such as Wi-Fi Beacon or a GPS signal (step 603).
  • WCT Wireless Clock Transmitter
  • Wireless Clock Receiver (WCR) 606 receives the transmitted clock reference and information about the source clock (at step 605) and sends a replicated source Clock signal to HDMI sink 608.
  • WCT and WCR periodically synchronize (step 607) and re-synchronize (step 611) between each other.
  • the request for synchronization can come from the Wireless Clock Receiver.
  • the system also does automatic re-synchronization (step 611).
  • a replicated source clock signal based on the local clock information is sent to a destination sink (step 609)
  • FIGS 7 and 8 show an example process of how the clock reference is transmitted in accordance with this disclosure.
  • the clock transmitter first obtains a wireless clock reference (WCR), such as Wi-Fi beacon or local GPS clock (step 701).
  • WCR wireless clock reference
  • SCR source clock reference
  • the transmitter After calculating the clock difference (WrlsClkErr) between the SCR and the WCR (step 705), the transmitter transmits the WrlsClkErr and the WCR to the receiver (step 707).
  • the receiver receives the WCR and the WrlsClkErr (step 801) and calculates the SCR using WCR and WrlsClkErr (step 803) and Using its local clock as the base (step 805), the receiver replicates the SCR by adding the local clock phase and sends the replicated SCR to the sink (step 805).
  • FIG. 9 shows an example of using Wi-Fi beacon as the wireless clock reference (WCR) in transmitting and receiving a source clock line.
  • Wi-Fi beacon 901 is transmitted at 10 kHz and the HDMI source clock 903 is transmitted at 50 mHz
  • the closest clock error (WlrsClkErr) between 901 and 903 is then calculated as p (913) which is transmitted to a receiver by the wireless clock transmitter.
  • the Wi-Fi beacon clock frames arrive as 907 and the WlrsClkErr value p is also received.
  • the original Wi-Fi beacon frames are estimated as 917.
  • the source clock reference (SCR) frames 911 are then estimated using source clock frequency information and by adding p to the estimated Wi-Fi beacon 917 clock frames.
  • Initial Phase Difference 919 is calculated (and recalculated during re-synchronization) which is done by using Subsequent Phase Tracking via using Phase Lock Loop.
  • FIG. 10 shows an example of using GPS as the wireless clock reference (WCR) where the GPS clock frames are derived from the local GPS receiver module.
  • the derived GPS clock frames 1001 at the transmitter side are used to calculate the clock error WlrsClkErr p (1013) between the HDMI source clock frames 1003 and the GPS clock frames 1001.
  • the closest clock error p between 1001 and 1003 is transmitted to a receiver.
  • the GPS clock frames 1007 are received and derived in the same way as 1001 from the local GPS receiver module.
  • the source clock reference (SCR) clock frames 1009 are estimated using source clock frequency information and by adding WlrsClkErr value p to GPS Clock frames 1007.
  • the Initial Phase Difference 1011 is calculated (and recalculated in re-synchronization) which is done by using Subsequent Phase Tracking via using Phase Lock Loop.
  • the estimated SCR 1009 is then replicated by taking into account the initial phase difference 1011 with the local clock frames and is replicated at the starting of the next local clock phase by shifting the start of the SCR clock frames with Initial Phase Difference 919.
  • Replicated SCR 1015 frames are then sent to a destination sink.
  • the Source Clock Signal is sent to the Sink when the data (10 bits in HDMI for example) is ready to be clocked out to the Sink.
  • the transmission of data to the Sink from the Wireless Clock Receiver is adjusted based on the time at which the Replicated Source Clock Signal is sent to the Sink. So instead of sending the clock when data is ready, the data is made ready when the clock occurs. There may or may not be a periodic transmission from the WCR to the Sink.
  • the program is stored on a computer accessible storage medium at a transmitter which is a part of or attached to a station, for example, a device coordinator or devices as shown in FIG. 1.
  • the program can be stored in other system locations so long as it can perform the transmitting procedure according to embodiments of the invention.
  • the storage medium may comprise any of a variety of technologies for storing information.
  • the storage medium comprises a random access memory (RAM), hard disks, floppy disks, digital video devices, compact discs, video discs, and/or other optical storage mediums, etc.
  • at least one of the device coordinator and devices comprises a processor configured to or programmed to perform the transmitting procedure.
  • the program may be stored in the processor or a memory of the coordinator and/or the devices.
  • the processor may have a configuration based on Intel Corporation's family of microprocessors, such as the Pentium family and Microsoft Corporation's Windows operating systems such as Windows 95, Windows 98, Windows 2000 or Windows NT.
  • the processor is implemented with a variety of computer platforms using a single chip or multi-chip microprocessors, digital signal processors, embedded microprocessors, microcontrollers, etc.
  • the processor is implemented with a wide range of operating systems such as Unix, Linux, Microsoft DOS, Microsoft Windows 2000/9x/ME/XP, Macintosh OS, OS/2 and the like.
  • the transmitting procedure can be implemented with an embedded software.
  • a method for synchronizing wireless data comprising actions of: receiving first source clock frames of a datastream and receiving the clock frames of a Wi-Fi beacon by a transmitter; calculating the clock difference between said Wi-Fi beacon clock frames and said first source clock frames; and transmitting said clock difference wirelessly; receiving said Wi-Fi beacon clock frames by a receiver; and obtaining the timestamp of said received Wi-Fi beacon clock frames and further comprising actions of: receiving said clock difference by the receiver; and constructing second source clock frames using said received clock difference and said timestamp; actions of: calculating an Initial Phase Difference between the local clock frames of the receiver and said second source clock frames; constructing third source clock frames using said Initial Phase Difference and said second source clock frames; and sending said third source clock frames to a destination player.
  • a method for wirelessly transmitting HDMI datastream comprising actions of: multiplexing a HDMI datastream into plurality of channels of data substreams; obtaining first source clock frame information of said HDMI datastream; calculating the clock difference between said first source clock frames and the clock frames of a Wi-Fi beacon; and transmitting wirelessly said data substreams and said clock difference to a receiver to which said Wi-Fi beacon is also available; and further comprising: receiving said plurality of channels of data substreams by said receiver; processing said data substreams to make them ready for output; receiving said clock difference by said receiver; receiving the clock frames of said Wi-Fi beacon by said receiver; constructing a second Wi-Fi beacon reference clock frames using the timestamps of said received Wi-Fi beacon reference clock frames; constructing second source clock frames using said second Wi-Fi beacon reference clock frames and said clock difference; and further comprising: calculating the Initial Phase Difference between the local clock frames of the receiver and said second source clock frames; constructing third source clock frames using said Initial
  • a wireless system for wirelessly transmitting a digital datastream comprising: a wireless transmitter which includes a processing unit that in operation multiplexes a digital datastream into plurality of channels of data substreams, obtains first source clock frames of said digital datastream and the clock frames of a Wi-Fi beacon, and calculates the clock difference between said first source clock frames and the clock frames of said Wi-Fi beacon; and a radio frequency unit which in operation transmits wirelessly said data substreams and said clock difference to a receiver; and a wireless receiver which includes a radio frequency unit that in operation receives said Wi-Fi beacon clock frames and receives said clock difference; and a processing unit which in operation obtains the timestamp of the clock frames of said Wi-Fi beacon, and constructs second source clock frames using said clock difference and said timestamp and said first source clock; wherein said processing unit of said receiver further in operation calculates an Initial Phase Difference between the local clock frames of the receiver and said second source clock frames, constructs third source clock frames using
  • the implementation of the processing units and transmission of wireless signals comply with any existing standards and protocols.
  • any existing standards and protocols for example, not only the IEEE 802.1 In, but also other IEEE 802.11 series; the 2G/3G standards and protocols; Multimedia encoding and decoding comply with HDMI and ISO/IEC MPEG-I and MPEG-2, MPEG-4 standards, high definition DVD (HD-DVD) standard and multimedia messaging service (MMS standard from 3GPP); the ITU-T H.261/3/4 standards; Audio Video Standard (AVS) in China.
  • the control system may be designed as a personal device, communicates via the cellular communication system.

Abstract

Methods and systems for operating a wireless clock system for multimedia datastream transmission and display. Source clock frames are compared with a reference clock frames and the clock difference are transmitted to a wireless clock receiver which also receives the same reference clock frames. Source clock frames are re-constructed using the reference clock frames, clock difference information and the receiver's local clock system.

Description

Method and Apparatus for Wireless Clock Regeneration
METHOD AND APPARATUS FOR WIRELESS CLOCK REGENERATION CROSS-REFERENCE TO OTHER APPLICATION
[001] Priority is claimed from US Provisional Application 60/933,905 filed on June 11, 2007, and also US Provisional Application 60/930,051 filed on May 14, 2007, and US Provisional Application 60/933,901 filed on June 11, 2007, all of which are hereby incorporated by reference. This application may be related to the present application, or may merely have some drawings and/or disclosure in common.
BACKGROUND
[002] The present application relates to multi-media networks, more particularly, to wirelessly transmission of a clock line for multimedia data distribution. The content of the distribution includes, but not limited to, high-definition video, digital sound, satellite TV, cable TV, high speed data, games, etc. [003] Note that the points discussed below may reflect the hindsight gained from the disclosed inventions, and are not necessarily admitted to be prior art. [004] With the proliferation of high quality video, an increasing number of electronic devices, such as consumer electronic devices, utilize high definition (HD) video which can require multi-Gbps (bits per second) in bandwidth for transmission. The High-Definition Multimedia Interface (HDMI) specification allows transfer of uncompressed HD signals between devices via a cable. While consumer electronics makers are beginning to offer HDMI-compatible equipment, there is not yet a suitable wireless (e.g., radio frequency) technology that is capable of transmitting uncompressed HD video signals.
[005] The introduction of consumer friendly Wi-Fi technology has let home and office users create wireless local networks and connect two or more computers wirelessly to each other and a faster Internet line. This way there is no more poking holes in walls or tripping over Ethernet cables. People can access the internet anywhere in home and in office. The Wi-Fi technology is rapidly gaining acceptance as an alternative to a wired local area network (LAN). [006] A Wi-Fi enabled device such as a PC, game console, cell phone, MP3 player or a PGA can connect to the internet when within range of a wireless network that is connected to the Internet. The area covered by a Wi-Fi hotspot (Access Point) can be as little as a single room with wireless-opaque walls or as much as many square miles covered by overlapping access points. [007] Routers which incorporate a DSL or cable modem and a Wi-Fi access point are often used in homes and other premises, and provide Internet access and inter-networking to all devices connected via wireless or by cable into them. Devices supporting Wi-Fi can also be connected in ad-hoc mode for client-to- client connections without a router.
[008] Wi-Fi devices use unlicensed spectrum to provide access to a network, ameliorating the trouble of obtaining FCC license.
[009] In short, Wi-Fi allows LANs to be deployed without cabling for client devices, dramatically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.
[0010] However, current Wi-Fi technology has significant operational limitations as well as severe shortcomings in spectrum assignments.
[0011] A current typical Wi-Fi adapter operates at a maximum raw data rate of 54
Mbit/s, and suffers sometimes severe channel interferences and collisions.
[0012] Given that the current high definition multimedia are transmitted as 1-10
Gbit/s, the current Wi-Fi system, with 54 Mbit/s capacity, is powerless to transmit high definition video, audio and other multimedia. Although current Ultra Wide
Band technology can offer up to 5Gbit/s, its range usually is within 10 meters, and often is Line of Sight.
[0013] In most wireless communications, HD video is first compressed before transmitting to the wireless medium. Compression of the HD video is attractive because the overall required communication bandwidth and power can be significantly reduced, relative to transmission of the original, uncompressed video. However, with each compression and subsequent decompression of the video, some video information can be lost and the picture quality is degraded.
Wireless transmission of HDMI video/audio is key to operate a high quality home entertainment network.
[0014] Conventional HDMI cable contains multiple wired connections for data transfer including 1 wired line for CLOCK. This wire provides the source HDMI clock from a source, such as an HD DVD player to the destination HDMI clock, such as an HDMI plasma TV. This signal is required to synchronize the data for transfer and HDMI encryption. The HDMI cable connected between the source (e. g. DVD player) and the destination (e. g. TV) provides this CLOCK line. However, for a wireless system, where the DVD player is now connected to a wireless transmitter and the TV is connected to a wireless receiver, the CLOCK line is missing.
[0015] In most wireless system, data are transmitted as data packets. The access nodes obtain the data through a common IP multicast or broadcast group over an IP multicast network. Packets for the multicast or broadcast may arrive at the access nodes with differing delays due to non-synchronous nature of IP multicast or broadcast forwarding. Packets may also be non-synchronous because packets may be lost along the multicast forwarding path.
SUMMARY
[0016] This application discloses a novel system, device, and methods for providing a wireless clock line.
[0017] In one embodiment, an HDMI source clock is transmitted to Wireless Clock Transmitter (WCT) which transmits information regarding the source clock in relation to a reference radio frequency such as Wi-Fi Beacon or a GPS signal. A Wireless Clock Receiver (WCR) receives the transmitted clock reference and the information about the source clock and sends a replicated source Clock signal to a HDMI sink. WCT and WCR periodically synchronize and re-synchronize between each other at request or automatically.
[0018] In another embodiment, the request for synchronization can come from the Wireless Clock Receiver. Depending on the preset conditions, such as jitter thresholds, reset of configuration, etc, the system also does automatic re- synchronization periodically.
[0019] In one embodiment, Wi-Fi Beacon is used as wireless reference; in another embodiment, a local GPS (Global Positioning System) is used as a wireless reference.
[0020] In one embodiment, the smallest time difference between the source clock frame and the wireless reference clock frame is calculated and transmitted to a receiver, and such difference is used to estimate source clock frame on the receiver.
[0021] In one embodiment, Subsequent Phase Tracking is done by using Phase Lock Loop, and is used to replicate the source clock frame in the receiver's local clock system. The estimated source clock frame is replicated by taking into account the initial phase difference and is replicated at the starting time of the next local clock phase.
[0022] The disclosed innovations, in various embodiments, provide one or more of at least the following advantages:
[0023] Seamless integration of the wireless media transmission system with the existing media display and cable system;
[0024] Easy clock calculation and easy data synchronization between the transmitting system and the receiving system;
[0025] Reliable and flexible;
[0026] Economical and highly efficient.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The disclosed inventions will be described with reference to the accompanying drawings, which show important sample embodiments of the invention and which are incorporated in the specification hereof by reference, wherein:
[0028] FIG. 1 schematically shows an example of Picon macronetwork.
[0029] FIG. 2 depicts an example architecture of a Picon wireless multimedia gateway.
[0030] FIG. 3 depicts an example architecture of a Picon wireless multimedia adapter.
[0031] FIG. 4 depicts an example clock channel in a multi-streaming transmitting unit in a Picon system.
[0032] FIG. 5 depicts an example clock channel in a multi-streaming receiving unit in a Picon system.
[0033] FIG. 6 shows an example functional process of a wireless clock control system.
[0034] FIG. 7 shows a working process of a wireless clock control transmitter.
[0035] FIG. 8 shows a working process of a wireless clock control receiver.
[0036] FIG. 9 shows an operation process for transceiving a wireless clock control to a sink using Wi-Fi beacon clock frame.
[0037] FIG. 10 shows an operation process for transceiving a wireless clock control to a sink using local GPS clock frame. DETAILED DESCRIPTION OF SAMPLE EMBODIMENTS
[0038] The numerous innovative teachings of the present application will be described with particular reference to presently preferred embodiments (by way of example, and not of limitation).
[0039] High Definition (HD) signals are typically transmitted from one system to another using cables carrying DVI (Digital Video Interface) or HDMI (High Definition Multimedia Interface) signals. Conventionally, DVI/HDMI signals are conveyed using a signaling scheme known as Transition Minimized Differential Signaling (TMDS). In TMDS, video, audio, and control data are carried as a series of 24-bit words on three TMDS data channels with a separate TMDS channel for carrying clock information. Additionally, DVI/HDMI systems may include a separate bi-directional channel known as the Display Data Channel (DDC) for exchanging configuration and status information between a source and a sink, including information needed in support of High-Bandwidth Digital Content Protection (HDCP) encryption and decryption. In HDMI, an optional Consumer Electronic Control (CEC) protocol provides high-level control functions between audiovisual products.
[0040] The Picon wireless home network comprises Picon Media Server and Picon Receiver that can seamlessly and securely integrate into the conventional audio-video cable system and provides about 10x improvement in data throughput over standard Wi-Fi technology, thus enables consumers to stream high quality wireless video, digital audio and high speed data applications across multiple rooms in home and in office without the stress of cabling. In order to wirelessly transmit the multimedia information, the Picon system also provides an architecture to wirelessly transmit clock channels for data synchronization and for seamless integration into the conventional system.
[0041] A Picon system is compatible with existing wireless technology and High Definition Multimedia Interface (HDMI), IEEE 802.11, Multiple-in Multiple out (MIMO), standard Wi-Fi physical (PHY) and Media Access Control (MAC) layer, and existing IP protocols, extremely high bandwidth applications such as Voice IP (VOIP), streaming audio and video content (including high definition), multicast applications, and also supports convergent networks, and ad hoc networks.
[0042] On transmission, video, audio, and related information data signals are digitally encoded into a packetized data stream using a number of algorithms, including error protection and correction. A micro-controller may be included to control the overall operation, including selection of parameters, the set-up and control of components, channel selection, viewer access to different programming packages, blocking certain channels, packet loss prevention and other functions. The compression and de-compression of packetized data streams may be accomplished according to the Motion Picture Expert Group (MPEG) various standards and HDMI standards and specifications.
[0043] Figure 1 is a network diagram illustrating an example wireless communication network 100 according to an embodiment of the present disclosure. In the illustrated embodiment, the wireless network 100 comprises a plurality of devices including device 111, 113, 115, 117, 119, 121, 123, 125, 127, 129 etc. Each of the devices can be any of a variety of multimedia and/or wireless devices, including a DVD player, digital audio systems, analog or digital TV, camcorder, digital camera, printer, scanner, fax machine, copy machine, graphics processor, cell phone, personal digital assistant ("PDA"), personal computer ("PC"), laptop computer, PC card, special purpose equipment, access point, router, switch, base station controller, game machine, Wi-Fi phone, security camera, set top box, GPS, or any combination of these and other devices configured to process and handle large amount of data. The transmission of data from the access nodes to the mobile stations can be over one of a variety of wireless technologies, such as IEEE 802.11, 802.16, CDMA, OFDM, UMTS, HSDPA, etc. The networks can include CDMA, GSM, CDMA2000, W-CDMA, UMTS, WiFi, WiMAX and other known and developing networks. In the context of the invention as described below, the access nodes conform to IEEE 802.11, 802.16 and WiMAX standards.
[0044] With the aid of the Picon system, as shown in this embodiment, including Picon media server 102 and receiver 104, these media display devices, regardless of whether they were originally capable of wireless communication, will gain the capacity to communicate to other devices in the network wirelessly. These devices become not only the data receivers, but also data providers, when the communication is configured to be bi-directional. Other data sources can, as indicated by such as 101, 103, 105, 107, 109, be for any of a variety of cable TV, satellite system, gaming stations, broadband Internet, IPTVs etc., provided by outside service providers, including audio, video data, or application data or the combination thereof. Depending on the service providers, the communication with these data sources can be configured to be either uni-directional or bidirectional, that any of the above mentioned devices can send data to those service systems through the Picon media server/receiver wirelessly. The communication between the Picon media server and receiver may be configured to be bidirectional as well.
[0045] High rate digital data come into the network through wire or satellite dish, via conventional connections such as satellite set-top box 101, gaming stations 103, cable TV set-top box 105, DSL modem 107, IPTV set-top box 109 etc. The high rate digital data are transmitted to Picon Media Server 102 through wire for data processing into lower rate digital data stream. Processed data are then wirelessly transmitted to Picon Receiver 104 which is connected with individual display devices, such as, devices 111, 113, 115, 117, 119, 121, 123, 125, 127, 129. Picon Receiver 104, upon receiving the wirelessly transmitted lower rate data stream, recovers and restores the lower rate data streams into the original high rate data stream and then sends them to the respective corresponding play or display device. The wireless transmission may be based on Wi-Fi protocol (IEEE 802.11 or other protocol transmission protocols, such as Third Generation Partnership Project (3 GPP) 2G and 3 G Code Division Multiple Access (CDMA) technologies, using IP or IP secure protocols.
[0046] In the illustrated embodiment, the network 100 could be any of a variety of network types and topologies and employ any of a variety of types of protocols. For the sake of providing a straightforward description, the illustrated embodiment will be described as an IEEE 802.11 compliant. [0047] In one embodiment, the high data rate content streams from one or more data sources can either be encrypted or unencrypted; compressed or uncompressed. Before directly passing the data stream for processing, the Picon media server 102 can include other switches and routers to direct the input data steams to the correct processing port.
[0048] Figure 2 shows an example of transmitting of a wireless clock line in a Picon Wireless Multimedia Gateway. The PHY layer of a Picon transmitter includes one or more Wireless Multimedia Gateways that comprises both multi- streaming and multi-channelling mechanism. Multi-streaming mechanism comprises plurality of parallel Wi-Fi like multiplexing units which splits a single datastream into plurality of low rate (LR) bitstreams and distributes them among plurality of channels. The splitting of the original high rate data stream 201, for example of a high definition video, can be implemented using the Multiple-input and multiple-output (MIMO) technology as specified in IEEE 802. Hn. For multi-channeling mechanism (205), each data type is processed by data-type specific processing unit, such as processing unit for DDC/CEC processing, composite video processing, component video processing, S-video processing, data/VoIP processing, etc.; and each of the sub-streams can be further processed in parallel in a processing unit that formats the sub-streams into packets with header information for the receiver(s) and be transmitted through one or more antennas in parallel. The number of antennas and the use of a specific antenna may be dynamically controlled by a controlling module that disperses, prioritizes, and schedules the transmission of each sub-stream.
[0049] A wireless clock line is transmitted as 203 for periodical data synchronization.
[0050] Figure 3 shows an example of receiving of a clock line in a Picon Wireless
Multimedia Adapter. The PHY layer of a Picon receiver includes one or more
Wireless Multimedia Adapters that comprises multiple parallel Wi-Fi adapter-like units 301 which can further have more than two low-rate receiving channels, each of which are linked to one or multiple antennas to receive data packets originally transmitted from HDMI source or other high data rate sources, and receiving channels for ordinarily compressed data. Each of the received sub-streams of packets is further processed in a processing unit that de-formats the packets and checks for errors based on the header information. Such sub-streams of packets, depending the required criteria, may be further congregated in a multiplex converter to be outputted at high data rate (301), or can be outputted to the sink at a modified or a similar or the same data rate (305) as that of the original data streams.
[0051] A wireless clock line is received on a channel separate from other channels or on the same channels as the data channels and are processed and separately sent to a destination (303).
[0052] The Pico receiver can connect to devices using various external or internal interconnects such as PCI, miniPCI, USB, Cardbus and PC Card, or cable or digital TV connectors. The output data of a Picon receiver can be directly sent to a display device. For the signals that are originally analog, the output digital data may first be converted into analog signal by a digital to analog converter before sending to a display device.
[0053] In one embodiment, the application layer of the Picon transmitter includes a pre-processing module and a control module. The pre-processing module can perform pre-processing of the audio/video such as partitioning of encrypted and compressed data. The control module provides a standard way to exchange data stream information. Before a connection begins, the control module negotiates the data formats to be used, and when the need for the connection is completed, the control commands are used to stop the connection.
[0054] The transmission and receiving of the wireless signals are controlled by the control module which dynamically allocates channels based on performance statistics. In one embodiment, it monitors and analyzes the performance of each channel and allocates the channels dynamically based on their performances as well as the configuration criteria. For example, if one of the channels shows degradation in performance, that channel will be replaced with a more robust channel to avoid further packet losses. This way, the packets are first stored in a frame buffer and they are scheduled and classified dynamically before they are transmitted.
[0055] The control module dynamically maps communication channels and timeslots in a network so that multiple channels can be reused simultaneously throughout the network during the same timeslot in a fashion that does not create collisions. [0056] For example, the Picon media server serving as a central server first determines the network topology of its wireless communication network in order to identify its client nodes or client devices and the discrete link a node or client has. Timeslots for transmission of packets between server and a particular node device are then identified and a separate channel is assigned. The various timeslots and communication channels are dynamically mapped across the network to maximize throughput and then queued up packets are transmitted over the various channels during the various timeslots in accordance with the dynamically changing mapping. The dynamically changing mapping allows maximum flexibility for spikes in throughput by individual nodes and also accounts for efficient ingress and egress of nodes in the wireless network. [0057] For a HDMI video stream, as shown in FIG. 4, the control module directs the data stream to the correct processing module 400 for multi-plexing and multi- streaming. A single input datastream is split into plurality of sub-streams (409) by distributing the datastream on plurality of parallel processing units, which are further processed and packed for proper transmission (units 401 and 403), and are transmitted by application layer and PHY layer via multiple-channels. In the mean time, a wireless source clock and reference are processed and transmitted (411 and 413).
[0058] In FIG. 5, the Picon receiver 500 receives the wireless transmitted digital signals 509 from the transmitter by multiple antennas and channels 503 and conducts the reverse-processing to re-assemble signals received through its multiple channels to a single stream shown as 515 and to the original format or according to the configuration by processing unit 505 and multiplex unit 507. The mechanism of packet loss prevention is applied by dynamic channel assignment during the transmission to improve performance and efficiency. Although separate channels and antennas may not be required for clock information transmission, in FIG. 5, channel X and antenna 511 are dedicated to receive the wirelessly transmitted source clock and reference clock information which are further processed and synchronized before being sent to a destination sink (513). [0059] One embodiment of the structure of a Picon processing layer can further contain an add/drop multiplexer module which dynamically communicates with the FHY layer of fiber backhaul and the control unit and router unit; the control unit communicates with multiplexer, router/buffer/firewall/QoS and also the transceivers which includes encryption processor, Wi-Fi like chipset and set of radio frequency components and antennas.
[0060] Transition Minimized Differential Signaling (TMDS) protocol can be used for signal integration and congregation of the packets. In TMDS, video, audio, and control data are carried as a series of 24-bit words on three TMDS data channels with a separate TMDS channel for carrying clock information. Additionally, DVI/HDMI systems may include a separate bi-directional channel known as the Display Data Channel (DDC) for exchanging configuration and status information between a source and a sink, including information needed in support of High-Bandwidth Digital Content Protection (HDCP) encryption and decryption. In HDMI, an optional Consumer Electronic Control (CEC) protocol provides high-level control functions between audiovisual products. Wireless Clock Synchronization Mechanism
[0061] In a Picon system, the source HDMI clock is first obtained from a HDMI source, for example, a DVD player, by the transmitter. The transmitter then acts as a "proxy" for the destination, for example, a TV. So as far as the DVD player is concerned, it "thinks" it is indeed connected to the TV. Similarly on the receiver end, the receiver acts as the "proxy" for the source (DVD player). So as far as the TV is concerned, it "thinks" it is connected to the DVD player. So, the CLOCK information is obtained from the DVD player by the transmitter, and the TV can obtain the CLOCK information from the receiver. Since different receivers may receive the source information at a different time due to difference in distance and difference in processing time, to regenerate the original CLOCK information, in other words to synchronize the transmitter clock with the receiver clock, a reference CLOCK which is available at both the transmitter and the receiver is needed.
[0062] In a wireless communication system, a wireless host periodically transmits a beacon frame over one or more radio frequency (RF) channels. Each beacon frame provides information about the host, including a service set identifier to identify a specific wireless network, a carrier frequency, and the beacon interval, which specifies the amount of time between beacon transmissions. A wireless device that receives a beacon frame can use the information in the beacon frame to determine whether to associate with the host. [0063] Figure 6 depicts the general process for transmitting a CLOCK reference. An HDMI source clock 602 is transmitted (step 601) to Wireless Clock Transmitter (WCT) 604, which transmits information regarding the source clock in relation to a reference radio frequency such as Wi-Fi Beacon or a GPS signal (step 603). Wireless Clock Receiver (WCR) 606 receives the transmitted clock reference and information about the source clock (at step 605) and sends a replicated source Clock signal to HDMI sink 608. WCT and WCR periodically synchronize (step 607) and re-synchronize (step 611) between each other. The request for synchronization can come from the Wireless Clock Receiver. Depending on the preset conditions, such as jitter thresholds, reset of configuration, etc, the system also does automatic re-synchronization (step 611). A replicated source clock signal based on the local clock information is sent to a destination sink (step 609)
[0064] Figures 7 and 8 show an example process of how the clock reference is transmitted in accordance with this disclosure. The clock transmitter first obtains a wireless clock reference (WCR), such as Wi-Fi beacon or local GPS clock (step 701). The transmitter then uses its local clock as a base, obtains the source clock reference (SCR) (step 703). After calculating the clock difference (WrlsClkErr) between the SCR and the WCR (step 705), the transmitter transmits the WrlsClkErr and the WCR to the receiver (step 707).
[0065] At the receiver side, shown in FIG. 8, the receiver receives the WCR and the WrlsClkErr (step 801) and calculates the SCR using WCR and WrlsClkErr (step 803) and Using its local clock as the base (step 805), the receiver replicates the SCR by adding the local clock phase and sends the replicated SCR to the sink (step 805).
[0066] Figure 9 shows an example of using Wi-Fi beacon as the wireless clock reference (WCR) in transmitting and receiving a source clock line. In the figure, assuming the Wi-Fi beacon 901 is transmitted at 10 kHz and the HDMI source clock 903 is transmitted at 50 mHz, the closest clock error (WlrsClkErr) between 901 and 903 is then calculated as p (913) which is transmitted to a receiver by the wireless clock transmitter.
[0067] At the receiver, the Wi-Fi beacon clock frames arrive as 907 and the WlrsClkErr value p is also received. Using the timestamp in the clock frames and the arrived 907, the original Wi-Fi beacon frames are estimated as 917. The source clock reference (SCR) frames 911 are then estimated using source clock frequency information and by adding p to the estimated Wi-Fi beacon 917 clock frames. Using receiver's local clock frames 905 as base, Initial Phase Difference 919 is calculated (and recalculated during re-synchronization) which is done by using Subsequent Phase Tracking via using Phase Lock Loop. The estimated SCR 911 frames are then replicated by taking into account the initial phase difference 919 and are replicated at the starting time of the next local clock phase by shifting the start of the SCR clock frames with Initial Phase Difference 919. The replicated SCR 909 clock frames are then sent to a destination sink. [0068] Figure 10 shows an example of using GPS as the wireless clock reference (WCR) where the GPS clock frames are derived from the local GPS receiver module. The derived GPS clock frames 1001 at the transmitter side are used to calculate the clock error WlrsClkErr p (1013) between the HDMI source clock frames 1003 and the GPS clock frames 1001. The closest clock error p between 1001 and 1003 is transmitted to a receiver.
[0069] At the receiver side, the GPS clock frames 1007 are received and derived in the same way as 1001 from the local GPS receiver module. Then, the source clock reference (SCR) clock frames 1009 are estimated using source clock frequency information and by adding WlrsClkErr value p to GPS Clock frames 1007. Using receiver's local clock frames 1005 as the base, and the Initial Phase Difference 1011 is calculated (and recalculated in re-synchronization) which is done by using Subsequent Phase Tracking via using Phase Lock Loop. The estimated SCR 1009 is then replicated by taking into account the initial phase difference 1011 with the local clock frames and is replicated at the starting of the next local clock phase by shifting the start of the SCR clock frames with Initial Phase Difference 919. Replicated SCR 1015 frames are then sent to a destination sink.
[0070] In a wired connection, the Source Clock Signal is sent to the Sink when the data (10 bits in HDMI for example) is ready to be clocked out to the Sink. In case of the wireless connection, the transmission of data to the Sink from the Wireless Clock Receiver is adjusted based on the time at which the Replicated Source Clock Signal is sent to the Sink. So instead of sending the clock when data is ready, the data is made ready when the clock occurs. There may or may not be a periodic transmission from the WCR to the Sink. [0071] In one embodiment of the invention, the program is stored on a computer accessible storage medium at a transmitter which is a part of or attached to a station, for example, a device coordinator or devices as shown in FIG. 1. In another embodiment, the program can be stored in other system locations so long as it can perform the transmitting procedure according to embodiments of the invention. The storage medium may comprise any of a variety of technologies for storing information. In one embodiment, the storage medium comprises a random access memory (RAM), hard disks, floppy disks, digital video devices, compact discs, video discs, and/or other optical storage mediums, etc. [0072] In another embodiment, at least one of the device coordinator and devices comprises a processor configured to or programmed to perform the transmitting procedure. The program may be stored in the processor or a memory of the coordinator and/or the devices. In various embodiments, the processor may have a configuration based on Intel Corporation's family of microprocessors, such as the Pentium family and Microsoft Corporation's Windows operating systems such as Windows 95, Windows 98, Windows 2000 or Windows NT. In one embodiment, the processor is implemented with a variety of computer platforms using a single chip or multi-chip microprocessors, digital signal processors, embedded microprocessors, microcontrollers, etc. In another embodiment, the processor is implemented with a wide range of operating systems such as Unix, Linux, Microsoft DOS, Microsoft Windows 2000/9x/ME/XP, Macintosh OS, OS/2 and the like. In another embodiment, the transmitting procedure can be implemented with an embedded software. Depending on the embodiments, additional states may be added, others removed, or the order of the states changes. [0073] According to various embodiments, there is provided: a method for synchronizing wireless data, comprising actions of: receiving first source clock frames of a datastream and receiving the clock frames of a Wi-Fi beacon by a transmitter; calculating the clock difference between said Wi-Fi beacon clock frames and said first source clock frames; and transmitting said clock difference wirelessly; receiving said Wi-Fi beacon clock frames by a receiver; and obtaining the timestamp of said received Wi-Fi beacon clock frames and further comprising actions of: receiving said clock difference by the receiver; and constructing second source clock frames using said received clock difference and said timestamp; actions of: calculating an Initial Phase Difference between the local clock frames of the receiver and said second source clock frames; constructing third source clock frames using said Initial Phase Difference and said second source clock frames; and sending said third source clock frames to a destination player.
[0074] According to various embodiments, there is provided: a method for wirelessly transmitting HDMI datastream, comprising actions of: multiplexing a HDMI datastream into plurality of channels of data substreams; obtaining first source clock frame information of said HDMI datastream; calculating the clock difference between said first source clock frames and the clock frames of a Wi-Fi beacon; and transmitting wirelessly said data substreams and said clock difference to a receiver to which said Wi-Fi beacon is also available; and further comprising: receiving said plurality of channels of data substreams by said receiver; processing said data substreams to make them ready for output; receiving said clock difference by said receiver; receiving the clock frames of said Wi-Fi beacon by said receiver; constructing a second Wi-Fi beacon reference clock frames using the timestamps of said received Wi-Fi beacon reference clock frames; constructing second source clock frames using said second Wi-Fi beacon reference clock frames and said clock difference; and further comprising: calculating the Initial Phase Difference between the local clock frames of the receiver and said second source clock frames; constructing third source clock frames using said Initial Phase Difference and said second source clock frames and; making said datastream ready for output before said third source clock frames start.
[0075] According to various embodiments, there is provided: a wireless system for wirelessly transmitting a digital datastream, comprising: a wireless transmitter which includes a processing unit that in operation multiplexes a digital datastream into plurality of channels of data substreams, obtains first source clock frames of said digital datastream and the clock frames of a Wi-Fi beacon, and calculates the clock difference between said first source clock frames and the clock frames of said Wi-Fi beacon; and a radio frequency unit which in operation transmits wirelessly said data substreams and said clock difference to a receiver; and a wireless receiver which includes a radio frequency unit that in operation receives said Wi-Fi beacon clock frames and receives said clock difference; and a processing unit which in operation obtains the timestamp of the clock frames of said Wi-Fi beacon, and constructs second source clock frames using said clock difference and said timestamp and said first source clock; wherein said processing unit of said receiver further in operation calculates an Initial Phase Difference between the local clock frames of the receiver and said second source clock frames, constructs third source clock frames using said Initial Phase Difference and said local clock frames, makes said datastream ready for output before said third source clock frames start and outputs said datastream and said third source clock frames simultaneously to a player; wherein said datastream includes one or the combination of high definition video streams, high definition audio streams, digital video signals, digital gaming data, internet content, IPTV signals, and satellite signals; wherein said processing unit of said receiver further in operation synchronizes said third source clock frames with said first source clock frames periodically; wherein said processing unit of said receiver further in operation synchronizes said third source clock frames with said first source clock frames at request; wherein said processing unit of said receiver further in operation synchronizes said third source clock frames with said first source clock frames automatically when a pre-set jitter threshold is reached.
Modifications and Variations
[0076] As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and varied over a tremendous range of applications, and accordingly the scope of patented subject matter is not limited by any of the specific exemplary teachings given. It is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
[0077] It is contemplated and considered that the implementation of the processing units and transmission of wireless signals comply with any existing standards and protocols. For example, not only the IEEE 802.1 In, but also other IEEE 802.11 series; the 2G/3G standards and protocols; Multimedia encoding and decoding comply with HDMI and ISO/IEC MPEG-I and MPEG-2, MPEG-4 standards, high definition DVD (HD-DVD) standard and multimedia messaging service (MMS standard from 3GPP); the ITU-T H.261/3/4 standards; Audio Video Standard (AVS) in China.
[0078] The control system may be designed as a personal device, communicates via the cellular communication system.
[0079] None of the description in the present application should be read as implying that any particular element, step, or function is an essential element which must be included in the claim scope: THE SCOPE OF PATENTED SUBJECT MATTER IS DEFINED ONLY BY THE ALLOWED CLAIMS. Moreover, none of these claims are intended to invoke paragraph six of 35 USC section 112 unless the exact words "means for" are followed by a participle. [0080] The claims as filed are intended to be as comprehensive as possible, and NO subject matter is intentionally relinquished, dedicated, or abandoned.

Claims

CLAIMS What is claimed is:
1. A method for synchronizing wireless data, comprising actions of: receiving first source clock frames of a datastream and receiving the clock frames of a Wi-Fi beacon by a transmitter; calculating the clock difference between said Wi-Fi beacon clock frames and said first source clock frames; and transmitting said clock difference wirelessly.
2. The method of Claim 1, further comprising: receiving said Wi-Fi beacon clock frames by a receiver; and obtaining the timestamp of said received Wi-Fi beacon clock frames.
3. The method of Claim 2, further comprising actions of: receiving said clock difference by the receiver; and constructing second source clock frames using said received clock difference and said timestamp.
4. The method of Claim 3, further comprising actions of: calculating an Initial Phase Difference between the local clock frames of the receiver and said second source clock frames; constructing third source clock frames using said Initial Phase Difference and said second source clock frames; and sending said third source clock frames to a destination player.
5. The method of Claim 4, further comprising actions of: synchronizing said third source clock frames with said first source clock frames periodically.
6. The method of Claim 4, further comprising actions of: synchronizing said third source clock frames with said first source clock frames at request.
7. The method of Claim 4, further comprising actions of: synchronizing said third source clock frames with said first source clock frames automatically when a pre-set jitter threshold is reached.
8. The method of Claim 4, further comprising actions of: making said datastream ready for output when said third source clock occurs; and sending said datastream to said destination player simultaneously when said third source clock frames are sent to said player.
9. The method of Claim 4, wherein said datasteam is one of or the combination of high definition video stream, high definition audio stream, digital gaming datastream, internet content, IPTV signals, digital satellite signals, and 2G/3G digital cellular signals.
10. A method for synchronizing wireless HDMI datastream, comprising: receiving first source clock frames of an HDMI datastream and receiving the clock frames of a Wi-Fi beacon by a wireless transmitter; calculating the clock difference between said Wi-Fi beacon clock frames and said first source clock frames; and transmitting said clock difference wirelessly.
11. The method of Claim 10, further comprising: receiving the clock frames of said Wi-Fi beacon by a receiver; and obtaining the timestamp of said received Wi-Fi beacon clock frames.
12. The method of Claim 11, further comprising: receiving said clock difference by the receiver; and constructing second source clock frames using said clock difference and said timestamp.
13. The method of Claim 12, further comprising: calculating an Initial Phase Difference between the local clock frames of the receiver and said second source clock frames; constructing third source clock frames using said second source clock frames and said Initial Phase Difference; and sending said third source clock frames to a display.
14. The method of Claim 13, further comprising actions of: synchronizing said third source clock frames with said first source clock frames periodically.
15. The method of Claim 13, further comprising actions of: synchronizing said third source clock frames with said first source clock frames at request.
16. The method of Claim 13, further comprising actions of: synchronizing said third source clock frames with said first source clock frames automatically as a pre-set jitter threshold is reached.
17. The method of Claim 13, further comprising actions of: making said HDMI datastream ready for output when said third source clock occurs; and sending said HDMI datastream to said display simultaneously as said third source clock frames are sent to said display.
18. A method for wirelessly transmitting HDMI datastream, comprising actions of: multiplexing a HDMI datastream into plurality of channels of data substreams; obtaining first source clock frame information of said HDMI datastream; calculating the clock difference between said first source clock frames and the clock frames of a Wi-Fi beacon; and transmitting wirelessly said data substreams and said clock difference to a receiver to which said Wi-Fi beacon is also available.
19. The method of Claim 18, further comprising: receiving said plurality of channels of data substreams by said receiver; processing said data substreams to make them ready for output; receiving said clock difference by said receiver; receiving the clock frames of said Wi-Fi beacon by said receiver; constructing a second Wi-Fi beacon reference clock frames using the timestamps of said received Wi-Fi beacon reference clock frames; constructing second source clock frames using said second Wi-Fi beacon reference clock frames and said clock difference;
20. The method of Claim 19, further comprising: calculating the Initial Phase Difference between the local clock frames of the receiver and said second source clock frames; constructing third source clock frames using said Initial Phase Difference and said second source clock frames and ; making said datastream ready for output before said third source clock frames start; and outputting said datastream and said third source clock frames simultaneously.
21. The method of Claim 20, further comprising actions of: synchronizing said third source clock frames with said first source clock periodically.
22. The method of Claim 20, further comprising actions of: synchronizing said third source clock frames with said source clock frames at request.
23. The method of Claim 20, further comprising actions of: synchronizing said third source clock frames with said source clock frames automatically as a pre-set jitter threshold is reached.
24. A wireless transmitter, comprising: a processing unit which in operation respectively receives first source clock frames of a datastream and receives the clock frame of a Wi-Fi beacon; and calculates the clock difference between the clock frames of said Wi-Fi beacon and said first source clock frames; and a radio frequency unit which transmits said clock difference.
25. The wireless transmitter of Claim 24, wherein said processing unit further in operation processes said datastream into plurality of channels of data packets; and dynamically allocates transmitting channels for said data packets for wireless transmitting.
26. The wireless transmitter of Claim 25, wherein said data packets are IP data packets.
27. The wireless transmitter of Claim 24, wherein said radio frequency unit complies with IEEE 802.1 In standards.
28. The wireless transmitter of Claim 24, wherein said radio frequency unit is implemented in accordance with the 3GPP standards.
29. The wireless transmitter of Claim 24, wherein said datastream includes one or the combination of high definition video streams, high definition audio streams, digital video signals, digital gaming data, internet content, IPTV signals, and satellite signals.
30. A wireless receiver, comprising: a radio frequency unit which in operation receives the clock frames of a Wi-Fi beacon and the clock difference between first source clock frames of a datastream and the clock frames of said Wi-Fi beacon which is transmitted from a wireless transmitter; and a processing unit which in operation obtains the timestamp of the clock frames of said Wi-Fi beacon, and constructs second source clock frames using said clock difference and said timestamp.
31. The wireless receiver of Claim 30, wherein said processing unit further in operation calculates an Initial Phase Difference between the local clock frames of the receiver and said first source clock frames; constructs third source clock frames using said second source clock frames and said Initial Phase Difference; and sends said third source clock frames to a destination player.
32. The wireless receiver of Claim 30, wherein said processing unit further in operation synchronizes said third source clock frames with said first source clock frames periodically.
33. The wireless receiver of Claim 30, wherein said processing unit further in operation processes said datasteam, and makes it ready for output before sending said third source clock frames to the player.
34. A wireless system for wirelessly transmitting a digital datastream, comprising: a wireless transmitter which includes a processing unit that in operation multiplexes a digital datastream into plurality of channels of data substreams, obtains first source clock frames of said digital datastream and the clock frames of a Wi-Fi beacon, and calculates the clock difference between said first source clock frames and the clock frames of said Wi-Fi beacon; and a radio frequency unit which in operation transmits wirelessly said data substreams and said clock difference to a receiver; and a wireless receiver which includes a radio frequency unit that in operation receives said Wi-Fi beacon clock frames and receives said clock difference; and a processing unit which in operation obtains the timestamp of the clock frames of said Wi-Fi beacon, and constructs second source clock frames using said clock difference and said timestamp and said first source clock.
35. The wireless system of Claim 34, wherein said processing unit of said receiver further in operation calculates an Initial Phase Difference between the local clock frames of the receiver and said second source clock frames, constructs third source clock frames using said Initial Phase Difference and said local clock frames, makes said datastream ready for output before said third source clock frames start and outputs said datastream and said third source clock frames simultaneously to a player.
36. The wireless system of Claim 34, wherein said datastream includes one or the combination of high definition video streams, high definition audio streams, digital video signals, digital gaming data, internet content, IPTV signals, and satellite signals.
37. The wireless system of Claim 34, wherein said processing unit of said receiver further in operation synchronizes said third source clock frames with said first source clock frames periodically.
38. The wireless system of Claim 34, wherein said processing unit of said receiver further in operation synchronizes said third source clock frames with said first source clock frames at request.
39. The wireless system of Claim 34, wherein said processing unit of said receiver further in operation synchronizes said third source clock frames with said first source clock frames automatically when a pre-set jitter threshold is reached.
40. A computer program containing medium, comprising: computer-readable material that contains computer operating instructions to convert a device into a wireless clock transmitter described in Claim 24.
41. The computer program containing medium of Claim 40, further comprising: computer-readable material that contains computer operating instructions to convert a device into a wireless clock transmitter described in Claim
25.
42. The computer program containing medium of Claim 40, further comprising: computer-readable material that contains computer operating instructions to convert a device into a wireless clock receiver described in Claim 30.
43. The computer program containing medium of Claim 40, further comprising: computer-readable material that contains computer operating instructions to convert a device into a wireless clock receiver described in Claim 31.
44. A computer program containing medium, comprising: computer-readable material that contains computer operating instructions to convert a device into a wireless system described in Claim 34.
45. A method for synchronizing wireless data, comprising actions of: receiving first source clock frame information of a datastream and receiving the clock frame of a wireless reference by a transmitter; calculating the clock difference between said wireless reference clock frames and said first source clock frames; and transmitting said clock difference wirelessly.
46. The method of Claim 45, further comprising: receiving the clock frames of said wireless reference by a receiver; and obtaining the timestamp of said received wireless reference clock frames.
47. The method of Claim 46, further comprising actions of: receiving said clock difference by the receiver; and constructing second source clock frames using received said clock difference and said timestamp.
48. The method of Claim 47, further comprising actions of: calculating an Initial Phase Difference between the local clock frames of the receiver and said second source clock frames; constructing third source clock frames using said Initial Phase Difference and said second source clock frames; and sending said third source clock frames to a destination player.
49. The method of Claim 48, further comprising actions of: synchronizing said third source clock frames with said first source clock frames periodically.
50. The method of Claim 48, further comprising actions of: synchronizing said third source clock frames with said first source clock frames at request.
51. The method of Claim 48, further comprising actions of: synchronizing said third source clock frames with said first source clock frames automatically when a pre-set jitter threshold is reached.
52. The method of Claim 48, further comprising actions of: making said datastream ready for output when said third source clock occurs; and sending said datastream to said destination player simultaneously when said third source clock frames are sent to said player.
53. The method of Claim 48, wherein said datasteam is one of or the combination of high definition video stream, high definition audio stream, digital gaming datastream, internet content, IPTV signals, digital satellite signals, and 2G/3G digital cellular signals.
54. A method of transmitting a signal in multiple channels, comprising: decomposing a first signal into multiple paralleled packet streams, and transmitting said packet streams over a Wi-Fi link which has an associated Wi-Fi beacon; and receiving said packet streams, and combining said packet streams to reproduce said first signal; wherein said decomposing and combining actions are mutually synchronized by using timing information from said Wi-Fi beacon.
55. The method of Claim 54, further comprising actions of: calculating the clock difference between the timing information of said Wi-Fi beacon and the clock frames of said first signal; and transmitting said clock difference wirelessly.
56. The method of Claim 55, further comprising: receiving said Wi-Fi beacon by a receiver; and obtaining the timestamp of said Wi-Fi beacon.
57. The method of Claim 56, further comprising actions of: receiving said clock difference by the receiver; and constructing second source clock frames using said received clock difference and said timestamp.
58. The method of Claim 57, further comprising actions of: calculating an Initial Phase Difference between the local clock frames of the receiver and said second source clock frames; constructing third source clock frames using said Initial Phase Difference and said second source clock frames; and sending said third source clock frames to a destination player.
59. The method of Claim 58, further comprising actions of: synchronizing said third source clock frames with the clock frames of said first signal periodically.
60. The method of Claim 58, further comprising actions of: synchronizing said third source clock frames with the clock frames of said first signal at request.
61. The method of Claim 58, further comprising actions of: synchronizing said third source clock frames with the clock frames of said first signal automatically when a pre-set jitter threshold is reached.
62. The method of Claim 58, further comprising actions of: making said packet stream ready for output when said third source clock occurs; and sending said packet stream to said destination player simultaneously when said third source clock frames are sent to said player.
63. The method of Claim 58, wherein said first signal is one of or the combination of high definition video stream, high definition audio stream, digital gaming datastream, internet content, IPTV signals, digital satellite signals, and 2G/3G digital cellular signals.
PCT/US2008/066512 2007-05-14 2008-06-11 Method and apparatus for wireless hdmi clock regeneration WO2008141341A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP08770669.3A EP2183873A4 (en) 2007-05-14 2008-06-11 Method and apparatus for wireless hdmi clock regeneration

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US93005107P 2007-05-14 2007-05-14
US60/930,051 2007-05-14
US93390107P 2007-06-11 2007-06-11
US93390507P 2007-06-11 2007-06-11
US60/933,905 2007-06-11
US60/933,901 2007-06-11

Publications (2)

Publication Number Publication Date
WO2008141341A1 WO2008141341A1 (en) 2008-11-20
WO2008141341A9 true WO2008141341A9 (en) 2009-01-08

Family

ID=40002660

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2008/066512 WO2008141341A1 (en) 2007-05-14 2008-06-11 Method and apparatus for wireless hdmi clock regeneration

Country Status (2)

Country Link
EP (1) EP2183873A4 (en)
WO (1) WO2008141341A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8671302B2 (en) 2007-05-14 2014-03-11 Picongen Wireless, Inc. Method and apparatus for wireless clock regeneration
US9451313B2 (en) * 2011-06-29 2016-09-20 Harman International Industries, Incorporated Network media adapter
JP6616064B2 (en) * 2013-07-25 2019-12-04 パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカ Transmission method and reception method

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7003062B1 (en) * 2001-02-14 2006-02-21 Cisco Systems Canada Co. Method and system for distribution of clock and frame synchronization information
US7120092B2 (en) * 2002-03-07 2006-10-10 Koninklijke Philips Electronics N. V. System and method for performing clock synchronization of nodes connected via a wireless local area network
US7151945B2 (en) * 2002-03-29 2006-12-19 Cisco Systems Wireless Networking (Australia) Pty Limited Method and apparatus for clock synchronization in a wireless network
KR100539230B1 (en) * 2003-02-26 2005-12-27 삼성전자주식회사 Physical layer unit providing for transmitting and receiving signals of several protocols, wireless Local Area Network system by the unit and wireless Local Area Network method
US7388857B2 (en) * 2004-04-12 2008-06-17 Samsung Electronics Co., Ltd. Method and system for synchronizing two end terminals using beacon synchronization with multiple channels in a wireless local area network
US7668243B2 (en) * 2004-05-18 2010-02-23 Texas Instruments Incorporated Audio and video clock synchronization in a wireless network

Also Published As

Publication number Publication date
WO2008141341A1 (en) 2008-11-20
EP2183873A4 (en) 2015-09-02
EP2183873A1 (en) 2010-05-12

Similar Documents

Publication Publication Date Title
US9191906B2 (en) Method and apparatus for wireless clock regeneration
US8875193B2 (en) Wireless multimedia system
US8284739B2 (en) Method and apparatus for affiliating a wireless device with a wireless local area network
US7623540B2 (en) Method and apparatus for channel allocation in a wireless local area network (WLAN)
RU2370907C2 (en) Method and device for conversion of mpeg transport stream into ip-packets for broadcasting in wlan
US20090002556A1 (en) Method and Apparatus for Packet Insertion by Estimation
US20060224763A1 (en) Switching and simultaneous usage of 802.11a and 802.11g technologies for video streaming
US20070028273A1 (en) Wireless satellite transverser with secured wireless infrastructure/ad-hoc modes
EP2683102B1 (en) Device and Method for transmitting samples of a digital baseband signal
US20080178243A1 (en) Multimedia client/server system with audio synchronization and methods for use therewith
US20100238836A1 (en) Method and system for timely delivery of multimedia content via a femtocell
US7653058B2 (en) Optical network for bi-directional wireless communication
Pilz et al. Professional live audio production: A highly synchronized use case for 5G URLLC systems
JP4563375B2 (en) Digital video synchronization method and apparatus using beacon packets
EP2183873A1 (en) Method and apparatus for wireless hdmi clock regeneration
NL2018130B1 (en) System and method for delivering video content
KR20100135154A (en) Method of messages exchanging and transmitting devices and receving devices
JP2016225744A (en) Radio communication system and method
CN111448818A (en) System and method for unlicensed spectrum transmission
KR20080113325A (en) Apparatus of transmitting real time moving picture using wireless multiple access, apparatus of receiving real time moving picture using wireless multiple access, apparatus of transmitting/receiving real time moving picture using wireless multiple access and method thereof
KR20080051091A (en) System and method for wireless communication of uncompressed media data packet synchronization

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08770669

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

REEP Request for entry into the european phase

Ref document number: 2008770669

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 2008770669

Country of ref document: EP