EP2160861A2 - Method of multiplexing transmission frame of digital broadcasting signal, apparatus for multiplexing transmission frame, and transmitting apparatus - Google Patents

Method of multiplexing transmission frame of digital broadcasting signal, apparatus for multiplexing transmission frame, and transmitting apparatus

Info

Publication number
EP2160861A2
EP2160861A2 EP08766459A EP08766459A EP2160861A2 EP 2160861 A2 EP2160861 A2 EP 2160861A2 EP 08766459 A EP08766459 A EP 08766459A EP 08766459 A EP08766459 A EP 08766459A EP 2160861 A2 EP2160861 A2 EP 2160861A2
Authority
EP
European Patent Office
Prior art keywords
service
time data
frame
time
buffer
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP08766459A
Other languages
German (de)
French (fr)
Other versions
EP2160861A4 (en
Inventor
Joung Il Yun
Gwang Soon Lee
Kwang-Yong Kim
Young Su Kim
Kyu Tae Yang
Jae-Hwui Bae
Seomee Choi
Ju Yeun Kim
Jae Hyun Seo
Jong Soo Lim
Soo In Lee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Electronics and Telecommunications Research Institute ETRI
Original Assignee
Electronics and Telecommunications Research Institute ETRI
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 Electronics and Telecommunications Research Institute ETRI filed Critical Electronics and Telecommunications Research Institute ETRI
Publication of EP2160861A2 publication Critical patent/EP2160861A2/en
Publication of EP2160861A4 publication Critical patent/EP2160861A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H60/00—Arrangements for broadcast applications with a direct linking to broadcast information or broadcast space-time; Broadcast-related systems
    • H04H60/02—Arrangements for generating broadcast information; Arrangements for generating broadcast-related information with a direct linking to broadcast information or to broadcast space-time; Arrangements for simultaneous generation of broadcast information and broadcast-related information
    • H04H60/07—Arrangements for generating broadcast information; Arrangements for generating broadcast-related information with a direct linking to broadcast information or to broadcast space-time; Arrangements for simultaneous generation of broadcast information and broadcast-related information characterised by processes or methods for the generation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/02—Speed or phase control by the received code signals, the signals containing no special synchronisation information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/04—Speed or phase control by synchronisation signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
    • H04N21/236—Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary stream
    • H04N21/23602—Multiplexing isochronously with the video sync, e.g. according to bit-parallel or bit-serial interface formats, as SDI
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
    • H04N21/236—Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary stream
    • H04N21/23614—Multiplexing of additional data and video streams
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/65—Arrangements characterised by transmission systems for broadcast
    • H04H20/67—Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency

Definitions

  • the present invention relates to a method of multiplexing a transmission frame of a digital broadcasting signal, an apparatus for multiplexing a transmission frame, and a transmitting apparatus.
  • the present invention relates to a method of multiplexing a transmission frame of a digital broadcasting signal, an apparatus for multiplexing a transmission frame, and a transmitting apparatus, which can send a transmission frame for each of a plurality of ensembles including service streams for the same service at the same point of time in terrestrial digital multimedia broadcasting (DMB).
  • DMB terrestrial digital multimedia broadcasting
  • Terrestrial digital multimedia broadcasting is a multimedia service that provides stereo quality in the compact disc (CD) range and image quality in the video range through a very high-frequency band having a bandwidth of approximately 1.5 MHz in mobile communication.
  • a transmitting apparatus multiplexes service streams on each of a plurality of different services into an ensemble, and transmits a transmission frame in the ensemble basis. Then, the transmission frame is modulated by a coded orthogonal frequency division multiplexing (COFDM) encoder and sent as a DMB broadcasting signal.
  • COFDM coded orthogonal frequency division multiplexing
  • the transmitting apparatus transmits a plurality of transmission frames including a plurality of service streams, which are generated in regard to any service
  • a receiving apparatus needs to receive all of the plurality of transmission frames including the service frames for the corresponding service so as to provide the service to the users.
  • the receiving apparatus needs to include a large- capacity buffer, which can store a plurality of transmission frames.
  • it takes a lot of time for the receiving apparatus to decode a plurality of service streams, which are multiplexed into a plurality of transmission frames.
  • the present invention has been made in an effort to provide a method of multiplexing a transmission frame, an apparatus for multiplexing a transmission frame, and a transmitting apparatus, having an advantage of sending a transmission frame for each of a plurality of ensembles including service streams for the same service at the same point of time.
  • An exemplary embodiment of the invention provides an apparatus for multiplexing a frame.
  • the apparatus includes: a first buffer that stores a first service stream transmitted from the outside; a second buffer that stores a second service stream transmitted from the outside; a time comparator that compares first service time data about the first service stream with second service time data about the second service stream; a first frame generator that outputs a first frame including the first service stream output from the first buffer; a second frame generator that outputs a second frame including the second service stream output from the second buffer; and a time stamp generator that generates first sending time data to be constructed in a time stamp field of the first frame and second sending time data to be constructed in a time stamp field of the second frame.
  • the time stamp generator may generate the first sending time data and the second sending time data as the same data.
  • the first sending time data may be used to determine a point of time to send the first frame
  • the second sending time data may be used to determine a point of time to send the second frame.
  • the time comparator may synchronize a point of time at which the first buffer outputs the first service stream with a point of time at which the second buffer outputs the second service stream.
  • the apparatus may further include a global positioning system (GPS) receiver that receives a standard time for generating the first sending time data and the second sending time data from at least one satellite.
  • GPS global positioning system
  • the apparatus may further include a first buffer output controller that controls the output of the first service stream according to a sequence of the first service time data and the second service time data, and a second buffer output controller that controls the output of the second service stream according to the sequence.
  • the apparatus may further include a first time information extractor that recognizes the first service time data from the first service stream, and a second time information extractor that recognizes the second service time data from the second service stream.
  • Another embodiment of the present invention provides a method of multiplexing a frame.
  • the method includes: storing, in a first buffer and a second buffer, a plurality of service streams including a first service stream and a second service stream; detecting service time data of each of the plurality of service streams; comparing a plurality of service time data corresponding to the plurality of service streams with each other; generating a first frame including the first service stream; generating a second frame including the second service stream; and, if first service time data corresponding to the first service stream stored in the first buffer is identical to second service time data corresponding to the second service stream stored in the second buffer, generating first sending time data to be constructed in a time stamp field of the first frame and second sending time data to be constructed in a time stamp field of the second frame as the same data.
  • the method may further include, if the first service time data and the second service time data are identical to each other, outputting the first service stream and the second service stream at the same point of time.
  • the method may further include setting a time at which the first service stream is maintained in the first buffer and a time at which the second service stream is maintained in the second buffer, such that the first service stream and the second service stream are output at the same point of time.
  • the method may further include, if the first service time data and the second service time data are identical to each other, generating the first frame and the second frame at the same point of time.
  • the method may further include outputting a plurality of frames corresponding to the plurality of service streams according to a sequence of the plurality of service time data.
  • Still another embodiment of the present invention provides a transmitting apparatus.
  • the transmitting apparatus includes: a first transmitter that receives a first frame from the outside, and sends the first frame according to first sending time data in a time stamp field of the first frame; and a second transmitter that receives a second frame from the outside, and sends the second frame according to second sending time data in a time stamp field of the second frame.
  • the first transmitter and the second transmitter may be independently driven.
  • a point of time at which the first transmitter sends the first frame may be identical to a point of time at which the second transmitter sends the second frame.
  • the transmitting apparatus may further include a GPS receiver that receives a standard time for recognizing the first sending time data and the second sending time data from at least one satellite.
  • the first transmitter and the second transmitter may send signals with the same modulation frequency.
  • the first transmitter and the second transmitter may send signals with different modulation frequencies.
  • FIG. 1 is a block diagram showing a digital multimedia broadcasting (DMB) transmission system according to an exemplary embodiment of the present invention.
  • DMB digital multimedia broadcasting
  • FIG. 2 is a diagram schematically showing the hierarchical structure of an ensemble transport interface (ETI) according to an exemplary embodiment of the present invention.
  • ETI ensemble transport interface
  • FIG. 3 is a diagram showing the structure of a frame corresponding to a logical interface (LI) layer of an ensemble transport interface (ETI).
  • LI logical interface
  • EI ensemble transport interface
  • FIG. 4 is a diagram schematically showing a DMB system for constructing a single frequency network (SFN).
  • SFN single frequency network
  • FIG. 5 is a flowchart illustrating a method of multiplexing a frame according to an exemplary embodiment of the present invention.
  • FIG. 6 is a block diagram showing an apparatus for multiplexing a frame according to an exemplary embodiment of the present invention.
  • FIG. 7 is a diagram showing a frame synchronization transmitting apparatus according to an exemplary embodiment of the present invention. Mode for the Invention
  • a method of multiplexing a frame of a digital broadcasting signal, an apparatus for multiplexing a frame, and a transmitting apparatus according to an exemplary embodiment of the present invention will now be described in detail with reference to the accompanying drawings.
  • a terrestrial DMB according to an exemplary embodiment of the present invention multiplexes each of the service streams for video, audio, or data services to an ensemble, and modulates and sends a transmission frame of the ensemble.
  • FIG. 1 is a block diagram showing a DMB transmission system according to an exemplary embodiment of the present invention.
  • a DMB transmission system includes a video service encoder
  • an audio service encoder 120 an audio service encoder 120, a data service encoder 130, an apparatus for multiplexing an ensemble (hereinafter, also referred to as “ensemble multiplexing apparatus” or “frame multiplexing apparatus”) 200, and a transmitting apparatus 300.
  • ensemble multiplexing apparatus an apparatus for multiplexing an ensemble
  • transmitting apparatus 300 an apparatus for transmitting an ensemble
  • the video service encoder 110 provides a video service
  • Each of the video service encoder 110, the audio service encoder 120, and the data service encoder 130 is operated by a service provider. Each encoder converts a service into service streams, and transmits the service streams to the ensemble multiplexing apparatus 200 through a network.
  • the ensemble multiplexing apparatus 200 is operated by an ensemble provider.
  • the ensemble multiplexing apparatus 200 receives the service streams through the network, and multiplexes the service streams for the service to generate an ensemble.
  • the ensemble multiplexing apparatus 200 transmits an ensemble transport interface (ETI) frame of the ensemble (hereinafter, simply referred to as "ETI frame") to a plurality of transmitting apparatuses.
  • ETI ensemble transport interface
  • the transmitting apparatus 300 is operated by a transmission network provider.
  • the transmitting apparatus 300 modulates the ETI frame transmitted from the ensemble multiplexing apparatus 200 through the network and sends the modulated transmission frame to the individual terminals according to a coded orthogonal frequency division multiplexing (COFDM) scheme.
  • COFDM coded orthogonal frequency division multiplexing
  • the transmitting apparatuses 300 can send the transmission frames at the same point of time.
  • the transmission frames that are sent at the same point of time may be sent through a single frequency network (SFN), which uses the same modulation frequency, or a multiplex frequency network, which uses different modulation frequencies.
  • SFN single frequency network
  • FIG. 2 is a diagram schematically showing the hierarchical structure of an ensemble transport interface (ETI) according to an exemplary embodiment of the present invention.
  • ETI ensemble transport interface
  • the ETI frame which is the output signal of the ensemble multiplexing apparatus 200, is an interface, which is the base of the DMB transmission network.
  • the hierarchical structure of the ETI is defined by three layers including a logical interface (LI) layer, a network independent (NI) layer, and a network adaptation (NA) layer.
  • LI logical interface
  • NI network independent
  • NA network adaptation
  • the LI layer which is a primitive logical structure, defines primitive information for generating an ensemble. That is, the LI layer is an interface that constructs service streams for services in the fields, such as audio, video, and data, which are provided to the users.
  • the NI layer which is a physical interface layer for LI mapping, includes a primitive interface of the ETI-related equipment. That is, the NI layer is an interface that allows the frame generated in the LI layer to be transmitted to a transmitter within a comparatively short distance, or allows the frame to be transmitted to a transmitter through a transmission network having a comparatively low transmission error.
  • the NA layer is an error-free physical interface layer for the use in an error-prone network environment, compared with the NI layer.
  • the NA layer has a structure that is mapped to the LI layer. That is, the NA layer is an interface that allows the frame generated in the LI layer to be transmitted to the transmitter when an error is prone to occur in a path to a transmitter due to a comparatively long distance or a comparatively high transmission error.
  • ETI NI, G.703
  • ETI NI, V.11
  • ETI NA, G.704
  • NI, G.703 ETI (NI, G.703)
  • NI, V.11 ETI (NI, V.11)
  • NA, G.704 ETI
  • NI, G.703 is used as a main interface between the equipment that transmits the ensembles. This is a standard input interface of a COFDM modulator.
  • FIG. 3 is a diagram showing the structure of a frame corresponding to a logical interface (LI) layer of an ensemble transport interface (ETI).
  • LI logical interface
  • EI ensemble transport interface
  • the frame (hereinafter referred to as "ETI frame") corresponding to the LI layer of the ETI is largely divided into a status (STAT) field and a logical interface data (LIDATA) field.
  • the STAT field includes an error status (ERR) field.
  • the LIDATA field includes a frame characterization (FC) field, a stream characterization (STC) field, an end-of-header (EOH) field, a main stream (MST) field, an end-of-frame (EOF) field, and a time stamp (TIST) field.
  • the FC field includes a frame count (FCT) field, a fast information channel (FIC) flag (hereinafter referred to as "FICF”) field, a number-of-streams (NST) field, a frame phase (FP) field, a mode (MID) field, and a frame length (FL) field.
  • FCT frame count
  • FICF fast information channel
  • NST number-of-streams
  • FP frame phase
  • MID mode
  • FL frame length
  • the STC field includes a plurality of sub-channel stream characterization (SSTC) fields.
  • Each of the SSTC fields includes a sub-channel identification (SCID) field, a start address (SAD) field, a protection level (TPL) field, and a stream length (STL) field.
  • SCID sub-channel identification
  • SAD start address
  • TPL protection level
  • STL stream length
  • the EOH field includes a multiplex network signaling channel (MNSC) field and a header CRC (CRCh) field.
  • MNSC multiplex network signaling channel
  • CRCh header CRC
  • the MST includes a plurality of fast information channel (FIC) and a plurality of streams.
  • FIC fast information channel
  • each stream of the MST are used to transmit service streams from each service encoder. That is, the MST is a main part of the frame that constructs data to broadcast.
  • the EOF field includes a cyclic redundancy check (CRC) field and a reserved (Rfu) field.
  • CRC cyclic redundancy check
  • Rfu reserved
  • the TIST field constructs data (hereinafter referred to as "sending time data”) about a time at which each transmitting apparatus sends the corresponding transmission frame.
  • the TIST field is used to construct a single frequency network (hereinafter, referred to as "SFN").
  • the sending time data to be constructed in the TIST field is determined in consideration of a time (hereinafter referred to as "delay time”) for which the transmission frame is transmitted from the ensemble multiplexing apparatus 200 to each transmitting apparatus.
  • FIG. 4 is a diagram schematically showing a digital multimedia broadcasting (DMB) system for constructing a single frequency network (SFN).
  • the single frequency network (SFN) means a network that is constituted from a plurality of transmitting apparatuses that send the same broadcasting with the same frequency. That is, a plurality of transmitting apparatuses correspondingly send the same transmission frame to the receiving apparatuses at the same point of time with the same modulation frequency.
  • the ETI frames generated by the ensemble multiplexing apparatus 410 are correspondingly transmitted to a first transmitting apparatus 421, a second transmitting apparatus 422, and a third transmitting apparatus 423 through a first path Rl, a second path R2, and a third path R3.
  • first delay time a time (hereinafter referred to as "first delay time") for which the transmission frame is transmitted from the ensemble multiplexing apparatus 410 to the first transmitting apparatus 421 through the first path Rl
  • second delay time a time (hereinafter referred to as "second delay time") for which the transmission frame is transmitted to the second transmitting apparatus 422 through the second path R2
  • third delay time a time (hereinafter referred to as "third delay time") for which the transmission frame is transmitted to the third transmitting apparatus 423 through the third path R3 are different from each other.
  • first transmitting apparatus 421, the second transmitting apparatus 422, and the third transmitting apparatus 423 send the same transmission frames at the same point of time can appropriate broadcasting be provided.
  • a point of time to send the transmission frame is determined in consideration of the first delay time, the second delay time, and the third delay time.
  • Data (hereinafter referred to as "sending time data") about the determined point of time to send the transmission frame is stored in the TIST field of the transmission frame.
  • each of the transmitting apparatuses 421, 422, and 423 sends the transmission frame at a point of time corresponding to the sending time data, which is constructed in the TIST field of the transmission frame. Accordingly, a plurality of transmitting apparatuses can send the same transmission frames at the same point of time according to the frame sending time data.
  • the ensemble multiplexing apparatus 410 generates a plurality of service streams for the service, and multiplexes a plurality of service streams to a plurality of different transmission frames.
  • the receiving apparatus receives a plurality of transmission frames including service streams for the same service at the comparatively same point of time, a load when the receiving apparatus receives a plurality of transmission frames can be reduced.
  • FIG. 5 is a flowchart illustrating a method of multiplexing a frame according to an exemplary embodiment of the present invention.
  • the ensemble multiplexing apparatus 410 receives a plurality of service streams for a service from a network (S510). Then, the plurality of service streams are correspondingly stored in the buffers.
  • the ensemble multiplexing apparatus 410 extracts time information ("service time data" in FIG. 5) (hereinafter referred to as "service time data”) from the plurality of received service streams (S520).
  • service time data may be set to a time at which the corresponding service stream is serviced to each receiving apparatus or a time at which the service stream is generated.
  • the ensemble multiplexing apparatus 410 compares the service time data of the service streams, and searches the same service time data (S530).
  • S530 service time data
  • the ensemble multiplexing apparatus 410 generates a first ETI frame including the first service stream and a second ETI frame including the second service stream (S540).
  • the ensemble multiplexing apparatus 410 may output the first service stream and the second service stream at the same point of time, thereby simultaneously generating the first transmission frame including the first service stream and the second transmission frame including the second service stream.
  • the ensemble multiplexing apparatus 410 generates sending time data of the first ETI frame (hereinafter referred to as "first sending time data") in consideration of a delay time between the ensemble multiplexing apparatus 410 and each of the plurality of transmitting apparatuses 421, 422, and 423, and constructs the first sending time data in the TIST field of the first ETI frame.
  • the ensemble multiplexing apparatus 410 generates sending time data of the second ETI frame (hereinafter referred to as "second sending time data”) in consideration of the delay time, and constructs the second sending time data in the TIST field of the second ETI frame.
  • first ETI frame and the second ETI frame include the service frames having the same service time data, the first sending time data and the second sending time data are set to be identical to each other (S550).
  • the transmitting apparatus receives a plurality of ETI frames from the ensemble multiplexing apparatus, and extracts the sending time data constructed in the TIST field of each of the plurality of ETI frames. Next, the transmitting apparatus sequentially sends the plurality of transmission frames according to the sending time data of the transmission frames. In this case, the transmitting apparatus sends the first transmission frame and the second transmission frame having the same sending time data at the same point of time (S560).
  • a frame multiplexing apparatus includes: a plurality of buffers that temporarily store a plurality of service streams, which are received through different networks; a plurality of time information extractors that extract service time data from the individual service streams stored in the buffers; and a plurality of frame generators that generate ETI frames including at least one service stream output from the buffers according to a sequence of the service time data. In this case, the plurality of frame generators independently generate the ETI frames.
  • FIG. 6 is a block diagram showing a frame multiplexing apparatus according to an exemplary embodiment of the present invention. In FIG. 6, a frame multiplexing apparatus, which includes two buffers, two time information extractors that extract the service time data of the service streams stored in the buffers, and two frame generators, is shown.
  • the frame multiplexing apparatus includes a first buffer 611, a second buffer 612, a first time information extractor 621, a second time information extractor 622, a time comparator 630, a first buffer output controller 641, a second buffer output controller 642, a first frame generator 651, a second frame generator 652, a time stamp (TIST) generator 660, and a global positioning system (GPS) receiver 670.
  • the first buffer 611 temporarily stores the first service stream S610 received through the network
  • the second buffer 612 temporarily stores the second service stream S620 received through the network.
  • the first service stream S610 and the second service stream S620 are multiplexed to different ensembles.
  • the first time information extractor 621 outputs service time data of the first service stream S610 (hereinafter referred to as "first service time data") stored in the first buffer 611.
  • the second time information extractor 622 outputs service time data of the second service stream S620 (hereinafter referred to as "second service time data") stored in the second buffer 612.
  • the first time information extractor 621 and the second time information extractor 622 extract the first service time data and the second service time data at the same position of the first buffer 611 and the second buffer 621, respectively.
  • the time comparator 630 compares the first service time data with the second service time data. In this case, the time comparator 630 determines the points of time at which the first service stream and the second service stream are correspondingly output from the buffers, according to the sequence of the first service time data and the second service time data.
  • the time comparator 630 sets a time (hereinafter referred to as "first buffer output delay time") for which the first service stream S610 is temporarily stored in the first buffer 611 and a time (hereinafter referred to as "second buffer output delay time”) for which the second service stream S620 is temporarily stored in the second buffer 612, such that the second service stream S620 is output earlier than the first service stream S610.
  • the second buffer output delay time is smaller than the first buffer output delay time so that the first service stream and the second service stream having the same service time data are correspondingly output from the buffers later.
  • outputting the second service stream from the second buffer may be continuously performed and outputting the first service stream from the first buffer may be hold until a second service stream having the same service time data as the first service stream is received.
  • the time comparator 630 sets such that the first buffer output delay time is smaller than the second buffer output delay time. That is, the time comparator 630 sets the first buffer output delay time and the second buffer output delay time such that the first service stream S610 is output earlier than the second service stream S620. Accordingly, the first service stream and the second service stream having the same service time data are correspondingly output from the buffers later.
  • the time comparator 630 sets the first buffer output delay time and the second buffer output delay time such that the first buffer output delay time is the same as the second buffer output delay time. That is, the first service stream S610 is output from the first buffer 611 at the same time the second service stream S620 is output from the second buffer 612.
  • the first buffer output controller 641 controls the output of the first service stream
  • the second buffer output controller 642 controls the output of the second service stream S620 from the second buffer 612 according to the second buffer output delay time.
  • the first buffer output controller 641 and the second buffer output controller 642 are independently driven.
  • a point of time at which the first service stream S610 is output and a point of time at which the second service stream S620 is output may be identical to or different from each other.
  • the first frame generator 651 generates the first ETI frame including the first service stream S610 output to the first buffer 611 under the control of the first buffer output controller 641, and outputs the generated first ETI frame to the network.
  • the second frame generator 652 generates the second ETI frame including the second service stream S620 output from the second buffer 612 under the control of the second buffer output controller 642, and outputs the generated second ETI frame to the network.
  • the first frame generator 651 and the second frame generator 652 are independently driven.
  • the time stamp (TIST) generator 660 generates the first sending time data and the second sending time data using the standard time.
  • the first sending time data generated in the above-described manner is supplied to the first frame generator 651 and con- structed in the TIST field of the first ETI frame.
  • the second sending time data is supplied to the second frame generator 652 and constructed in the TIST field of the second ETI frame.
  • the first sending time data and the second sending time data are generated in consideration of the time (delay time) for which the transmission frame is transmitted from the ensemble multiplexing apparatus to the each transmitting apparatus.
  • the standard time can be obtained by a global positioning system
  • GPS Globalstar
  • GPS receiver 670 which acquires information about accurate time from at least three satellites.
  • FIG. 6 a case where the standard time is obtained using the GPS receiver has been illustrated.
  • the present invention is not limited thereto. Any method may be applied to the present invention insofar as it can obtain the standard time.
  • a transmitting apparatus includes a plurality of RF signal transmitters.
  • FIG. 7 is a diagram showing a transmitting apparatus according to an exemplary embodiment of the present invention.
  • a frame synchronization transmitting apparatus which only includes two RF transmitters for receiving two different transmission frames, is shown.
  • RF means radio frequency.
  • the frame synchronization transmitting apparatus includes a first
  • RF signal transmitter 711 a second RF signal transmitter 712, and a GPS receiver 720.
  • the first RF signal transmitter 711 and the second RF signal transmitter 712 individually receive different ETI frames. Then, each transmitter checks the TIST field of the received ETI frame and determines the sending time of the transmission frame.
  • the GPS receiver 720 is used to obtain the standard time for recognizing the frame sending time data, which is constructed in the TIST field of the received ETI frame.
  • the operation of the frame synchronization transmitting apparatus shown in FIG. 7 will be described below.
  • the first RF transmitter 711 receives the first ETI frame, which is transmitted from the ensemble multiplexing apparatus shown in FIG. 6, and sends the first transmission frame according to the frame sending time data, which is recognized using the TIST field of the first ETI frame and the standard time obtained by the GPS receiver 720.
  • the second RF transmitter 712 receives the second ETI frame, which is transmitted from the ensemble multiplexing apparatus, and sends the second transmission frame according to the frame sending time data, which is recognized using the TIST field of the second ETI frame and the standard time obtained by the GPS receiver 720.
  • the first RF transmitter 711 and the second RF transmitter 712 send the first transmission frame and the second transmission frame at the same point of time, respectively.
  • the first RF signal transmitter 711 and the second RF signal transmitter 712 may send the terrestrial DMB signals with different modulation frequencies.
  • the first RF signal transmitter 711 and the second RF signal transmitter 712 may be provided in an RF signal transmitter (not shown).
  • the RF signal transmitter (not shown) may send signals having the same TIST field value among the RF signals having the same frequency bandwidth at the same point of time by a transmitting method such as layered modulation.
  • a plurality of ETI frames including a plurality of service streams for any service can be simultaneously sent, without constructing an additional field so as to send two or more transmission frames at the same point of time. Accordingly, the receiving apparatus receives a plurality of transmission frames including service streams for the same service at substantially the same point of time. Therefore, a large-capacity buffer does not need to be provided, and it does not take a lot of time to decode the service.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Multimedia (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

In a terrestrial DMB, a transmitting apparatus multiplexes a plurality of service streams generated for any service to a plurality of ensembles. In this case, the same sending time data is constructed in a time stamp field of each frame for each of a plurality of ensembles. With this configuration, a plurality of transmitting apparatuses can send a plurality of transmission frames including service streams for the same service at the same point of time, and thus receiving apparatuses can actually receive a plurality of transmission frames at the same point of time.

Description

Description
METHOD OF MULTIPLEXING TRANSMISSION FRAME OF DIGITAL BROADCASTING SIGNAL, APPARATUS FOR MULTIPLEXING TRANSMISSION FRAME, AND TRANSMITTING
APPARATUS Technical Field
[1] The present invention relates to a method of multiplexing a transmission frame of a digital broadcasting signal, an apparatus for multiplexing a transmission frame, and a transmitting apparatus. In particular, the present invention relates to a method of multiplexing a transmission frame of a digital broadcasting signal, an apparatus for multiplexing a transmission frame, and a transmitting apparatus, which can send a transmission frame for each of a plurality of ensembles including service streams for the same service at the same point of time in terrestrial digital multimedia broadcasting (DMB).
[2] The present invention was supported by the IT R&D program of MIC/IITA
[2006-S-017-02, Development of Technology for Advancement of Terrestrial DMB
Transmission].
Background Art
[3] Terrestrial digital multimedia broadcasting (DMB) is a multimedia service that provides stereo quality in the compact disc (CD) range and image quality in the video range through a very high-frequency band having a bandwidth of approximately 1.5 MHz in mobile communication.
[4] In general, according to the terrestrial DMB system, a transmitting apparatus multiplexes service streams on each of a plurality of different services into an ensemble, and transmits a transmission frame in the ensemble basis. Then, the transmission frame is modulated by a coded orthogonal frequency division multiplexing (COFDM) encoder and sent as a DMB broadcasting signal.
[5] Meanwhile, when the transmitting apparatus transmits a plurality of transmission frames including a plurality of service streams, which are generated in regard to any service, a receiving apparatus needs to receive all of the plurality of transmission frames including the service frames for the corresponding service so as to provide the service to the users. Accordingly, the receiving apparatus needs to include a large- capacity buffer, which can store a plurality of transmission frames. In addition, it takes a lot of time for the receiving apparatus to decode a plurality of service streams, which are multiplexed into a plurality of transmission frames. [6] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. Disclosure of Invention Technical Problem
[7] The present invention has been made in an effort to provide a method of multiplexing a transmission frame, an apparatus for multiplexing a transmission frame, and a transmitting apparatus, having an advantage of sending a transmission frame for each of a plurality of ensembles including service streams for the same service at the same point of time. Technical Solution
[8] An exemplary embodiment of the invention provides an apparatus for multiplexing a frame. The apparatus includes: a first buffer that stores a first service stream transmitted from the outside; a second buffer that stores a second service stream transmitted from the outside; a time comparator that compares first service time data about the first service stream with second service time data about the second service stream; a first frame generator that outputs a first frame including the first service stream output from the first buffer; a second frame generator that outputs a second frame including the second service stream output from the second buffer; and a time stamp generator that generates first sending time data to be constructed in a time stamp field of the first frame and second sending time data to be constructed in a time stamp field of the second frame. In this case, if the first service time data and the second service time data are identical to each other, the time stamp generator may generate the first sending time data and the second sending time data as the same data.
[9] The first sending time data may be used to determine a point of time to send the first frame, and the second sending time data may be used to determine a point of time to send the second frame.
[10] If the first service time data and the second service time data are identical to each other, the time comparator may synchronize a point of time at which the first buffer outputs the first service stream with a point of time at which the second buffer outputs the second service stream.
[11] The apparatus may further include a global positioning system (GPS) receiver that receives a standard time for generating the first sending time data and the second sending time data from at least one satellite. The apparatus may further include a first buffer output controller that controls the output of the first service stream according to a sequence of the first service time data and the second service time data, and a second buffer output controller that controls the output of the second service stream according to the sequence. The apparatus may further include a first time information extractor that recognizes the first service time data from the first service stream, and a second time information extractor that recognizes the second service time data from the second service stream.
[12] Another embodiment of the present invention provides a method of multiplexing a frame. The method includes: storing, in a first buffer and a second buffer, a plurality of service streams including a first service stream and a second service stream; detecting service time data of each of the plurality of service streams; comparing a plurality of service time data corresponding to the plurality of service streams with each other; generating a first frame including the first service stream; generating a second frame including the second service stream; and, if first service time data corresponding to the first service stream stored in the first buffer is identical to second service time data corresponding to the second service stream stored in the second buffer, generating first sending time data to be constructed in a time stamp field of the first frame and second sending time data to be constructed in a time stamp field of the second frame as the same data.
[13] The method may further include, if the first service time data and the second service time data are identical to each other, outputting the first service stream and the second service stream at the same point of time.
[14] The method may further include setting a time at which the first service stream is maintained in the first buffer and a time at which the second service stream is maintained in the second buffer, such that the first service stream and the second service stream are output at the same point of time.
[15] The method may further include, if the first service time data and the second service time data are identical to each other, generating the first frame and the second frame at the same point of time. The method may further include outputting a plurality of frames corresponding to the plurality of service streams according to a sequence of the plurality of service time data.
[16] Still another embodiment of the present invention provides a transmitting apparatus.
The transmitting apparatus includes: a first transmitter that receives a first frame from the outside, and sends the first frame according to first sending time data in a time stamp field of the first frame; and a second transmitter that receives a second frame from the outside, and sends the second frame according to second sending time data in a time stamp field of the second frame. In this case, the first transmitter and the second transmitter may be independently driven.
[17] If the first sending time data and the second sending time data are identical to each other, a point of time at which the first transmitter sends the first frame may be identical to a point of time at which the second transmitter sends the second frame. The transmitting apparatus may further include a GPS receiver that receives a standard time for recognizing the first sending time data and the second sending time data from at least one satellite.
[18] The first transmitter and the second transmitter may send signals with the same modulation frequency. The first transmitter and the second transmitter may send signals with different modulation frequencies.
Advantageous Effects
[19] According to the embodiments of the present invention, although an additional field is not provided in the transmission frame, a plurality of transmission frames including service streams for the same service can be sent synchronously. Therefore, a service having such a small capacity to not be multiplexed to a single ensemble can be provided, without providing a large-capacity buffer in a receiving apparatus, and comparatively increasing a time required for decoding a plurality of service streams. Brief Description of the Drawings
[20] FIG. 1 is a block diagram showing a digital multimedia broadcasting (DMB) transmission system according to an exemplary embodiment of the present invention.
[21] FIG. 2 is a diagram schematically showing the hierarchical structure of an ensemble transport interface (ETI) according to an exemplary embodiment of the present invention.
[22] FIG. 3 is a diagram showing the structure of a frame corresponding to a logical interface (LI) layer of an ensemble transport interface (ETI).
[23] FIG. 4 is a diagram schematically showing a DMB system for constructing a single frequency network (SFN).
[24] FIG. 5 is a flowchart illustrating a method of multiplexing a frame according to an exemplary embodiment of the present invention.
[25] FIG. 6 is a block diagram showing an apparatus for multiplexing a frame according to an exemplary embodiment of the present invention.
[26] FIG. 7 is a diagram showing a frame synchronization transmitting apparatus according to an exemplary embodiment of the present invention. Mode for the Invention
[27] In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.
[28] In addition, unless explicitly described to the contrary, the word "comprise" and variations, such as "comprises" or "comprising", will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. The term "section", "-er (-or)", or "module" used herein mean a unit that processes at least one function or operation. This can be implemented by hardware, software, or a combination thereof.
[29] A method of multiplexing a frame of a digital broadcasting signal, an apparatus for multiplexing a frame, and a transmitting apparatus according to an exemplary embodiment of the present invention will now be described in detail with reference to the accompanying drawings. A terrestrial DMB according to an exemplary embodiment of the present invention multiplexes each of the service streams for video, audio, or data services to an ensemble, and modulates and sends a transmission frame of the ensemble.
[30] FIG. 1 is a block diagram showing a DMB transmission system according to an exemplary embodiment of the present invention.
[31] As shown in FIG. 1, a DMB transmission system includes a video service encoder
110, an audio service encoder 120, a data service encoder 130, an apparatus for multiplexing an ensemble (hereinafter, also referred to as "ensemble multiplexing apparatus" or "frame multiplexing apparatus") 200, and a transmitting apparatus 300.
[32] The video service encoder 110 provides a video service, the audio service encoder
120 provides an audio service, and the data service encoder 130 provides a data service. Each of the video service encoder 110, the audio service encoder 120, and the data service encoder 130 is operated by a service provider. Each encoder converts a service into service streams, and transmits the service streams to the ensemble multiplexing apparatus 200 through a network.
[33] The ensemble multiplexing apparatus 200 is operated by an ensemble provider. The ensemble multiplexing apparatus 200 receives the service streams through the network, and multiplexes the service streams for the service to generate an ensemble. In addition, the ensemble multiplexing apparatus 200 transmits an ensemble transport interface (ETI) frame of the ensemble (hereinafter, simply referred to as "ETI frame") to a plurality of transmitting apparatuses.
[34] The transmitting apparatus 300 is operated by a transmission network provider. The transmitting apparatus 300 modulates the ETI frame transmitted from the ensemble multiplexing apparatus 200 through the network and sends the modulated transmission frame to the individual terminals according to a coded orthogonal frequency division multiplexing (COFDM) scheme. At this time, the transmitting apparatuses 300 can send the transmission frames at the same point of time. The transmission frames that are sent at the same point of time may be sent through a single frequency network (SFN), which uses the same modulation frequency, or a multiplex frequency network, which uses different modulation frequencies.
[35] FIG. 2 is a diagram schematically showing the hierarchical structure of an ensemble transport interface (ETI) according to an exemplary embodiment of the present invention.
[36] As shown in FIG. 2, the ETI frame, which is the output signal of the ensemble multiplexing apparatus 200, is an interface, which is the base of the DMB transmission network.
[37] The hierarchical structure of the ETI is defined by three layers including a logical interface (LI) layer, a network independent (NI) layer, and a network adaptation (NA) layer.
[38] The LI layer, which is a primitive logical structure, defines primitive information for generating an ensemble. That is, the LI layer is an interface that constructs service streams for services in the fields, such as audio, video, and data, which are provided to the users.
[39] The NI layer, which is a physical interface layer for LI mapping, includes a primitive interface of the ETI-related equipment. That is, the NI layer is an interface that allows the frame generated in the LI layer to be transmitted to a transmitter within a comparatively short distance, or allows the frame to be transmitted to a transmitter through a transmission network having a comparatively low transmission error.
[40] The NA layer is an error-free physical interface layer for the use in an error-prone network environment, compared with the NI layer. The NA layer has a structure that is mapped to the LI layer. That is, the NA layer is an interface that allows the frame generated in the LI layer to be transmitted to the transmitter when an error is prone to occur in a path to a transmitter due to a comparatively long distance or a comparatively high transmission error.
[41] Various interfaces, such as ETI (NI, G.703), ETI (NI, V.11), ETI (NA, G.704), and the like, may be used according to the forms of interface signals to be used. Of these, ETI (NI, G.703) is used as a main interface between the equipment that transmits the ensembles. This is a standard input interface of a COFDM modulator.
[42] FIG. 3 is a diagram showing the structure of a frame corresponding to a logical interface (LI) layer of an ensemble transport interface (ETI).
[43] As shown in FIG. 3, the frame (hereinafter referred to as "ETI frame") corresponding to the LI layer of the ETI is largely divided into a status (STAT) field and a logical interface data (LIDATA) field. The STAT field includes an error status (ERR) field. The LIDATA field includes a frame characterization (FC) field, a stream characterization (STC) field, an end-of-header (EOH) field, a main stream (MST) field, an end-of-frame (EOF) field, and a time stamp (TIST) field.
[44] The FC field includes a frame count (FCT) field, a fast information channel (FIC) flag (hereinafter referred to as "FICF") field, a number-of-streams (NST) field, a frame phase (FP) field, a mode (MID) field, and a frame length (FL) field.
[45] The STC field includes a plurality of sub-channel stream characterization (SSTC) fields. Each of the SSTC fields includes a sub-channel identification (SCID) field, a start address (SAD) field, a protection level (TPL) field, and a stream length (STL) field.
[46] The EOH field includes a multiplex network signaling channel (MNSC) field and a header CRC (CRCh) field.
[47] The MST includes a plurality of fast information channel (FIC) and a plurality of streams. In this case, the FIC and each stream of the MST are used to transmit service streams from each service encoder. That is, the MST is a main part of the frame that constructs data to broadcast.
[48] The EOF field includes a cyclic redundancy check (CRC) field and a reserved (Rfu) field.
[49] The TIST field constructs data (hereinafter referred to as "sending time data") about a time at which each transmitting apparatus sends the corresponding transmission frame. The TIST field is used to construct a single frequency network (hereinafter, referred to as "SFN"). Here, the sending time data to be constructed in the TIST field is determined in consideration of a time (hereinafter referred to as "delay time") for which the transmission frame is transmitted from the ensemble multiplexing apparatus 200 to each transmitting apparatus.
[50] FIG. 4 is a diagram schematically showing a digital multimedia broadcasting (DMB) system for constructing a single frequency network (SFN). The single frequency network (SFN) means a network that is constituted from a plurality of transmitting apparatuses that send the same broadcasting with the same frequency. That is, a plurality of transmitting apparatuses correspondingly send the same transmission frame to the receiving apparatuses at the same point of time with the same modulation frequency.
[51] As shown in FIG. 4, the ETI frames generated by the ensemble multiplexing apparatus 410 are correspondingly transmitted to a first transmitting apparatus 421, a second transmitting apparatus 422, and a third transmitting apparatus 423 through a first path Rl, a second path R2, and a third path R3.
[52] In this case, a time (hereinafter referred to as "first delay time") for which the transmission frame is transmitted from the ensemble multiplexing apparatus 410 to the first transmitting apparatus 421 through the first path Rl, a time (hereinafter referred to as "second delay time") for which the transmission frame is transmitted to the second transmitting apparatus 422 through the second path R2, and a time (hereinafter referred to as "third delay time") for which the transmission frame is transmitted to the third transmitting apparatus 423 through the third path R3 are different from each other. However, only when the first transmitting apparatus 421, the second transmitting apparatus 422, and the third transmitting apparatus 423 send the same transmission frames at the same point of time can appropriate broadcasting be provided. Accordingly, a point of time to send the transmission frame is determined in consideration of the first delay time, the second delay time, and the third delay time. Data (hereinafter referred to as "sending time data") about the determined point of time to send the transmission frame is stored in the TIST field of the transmission frame.
[53] If the ETI frame is transmitted from the ensemble multiplexing apparatus 410, each of the transmitting apparatuses 421, 422, and 423 sends the transmission frame at a point of time corresponding to the sending time data, which is constructed in the TIST field of the transmission frame. Accordingly, a plurality of transmitting apparatuses can send the same transmission frames at the same point of time according to the frame sending time data.
[54] Meanwhile, in the case of a service that cannot be multiplexed to a single ensemble, the ensemble multiplexing apparatus 410 generates a plurality of service streams for the service, and multiplexes a plurality of service streams to a plurality of different transmission frames. In this case, if the receiving apparatus receives a plurality of transmission frames including service streams for the same service at the comparatively same point of time, a load when the receiving apparatus receives a plurality of transmission frames can be reduced.
[55] Hereinafter, a method and apparatus for multiplexing a frame in a terrestrial DMB system according to an exemplary embodiment of the present invention, which sends two or more transmission frames at the same point of time, will be described.
[56] FIG. 5 is a flowchart illustrating a method of multiplexing a frame according to an exemplary embodiment of the present invention.
[57] As shown in FIG. 5, first, the ensemble multiplexing apparatus 410 receives a plurality of service streams for a service from a network (S510). Then, the plurality of service streams are correspondingly stored in the buffers.
[58] The ensemble multiplexing apparatus 410 extracts time information ("service time data" in FIG. 5) (hereinafter referred to as "service time data") from the plurality of received service streams (S520). In this case, the service time data may be set to a time at which the corresponding service stream is serviced to each receiving apparatus or a time at which the service stream is generated.
[59] Next, the ensemble multiplexing apparatus 410 compares the service time data of the service streams, and searches the same service time data (S530). In the following description, for convenience of explanation, it is assumed that a first service stream and a second service stream that have the same service time data and cannot be multiplexed to a single ensemble are searched.
[60] Next, in regard to the first service stream and the second service stream having the same service time data, the ensemble multiplexing apparatus 410 generates a first ETI frame including the first service stream and a second ETI frame including the second service stream (S540). In this case, the ensemble multiplexing apparatus 410 may output the first service stream and the second service stream at the same point of time, thereby simultaneously generating the first transmission frame including the first service stream and the second transmission frame including the second service stream.
[61] Next, the ensemble multiplexing apparatus 410 generates sending time data of the first ETI frame (hereinafter referred to as "first sending time data") in consideration of a delay time between the ensemble multiplexing apparatus 410 and each of the plurality of transmitting apparatuses 421, 422, and 423, and constructs the first sending time data in the TIST field of the first ETI frame. Next, the ensemble multiplexing apparatus 410 generates sending time data of the second ETI frame (hereinafter referred to as "second sending time data") in consideration of the delay time, and constructs the second sending time data in the TIST field of the second ETI frame. In this case, since the first ETI frame and the second ETI frame include the service frames having the same service time data, the first sending time data and the second sending time data are set to be identical to each other (S550).
[62] The transmitting apparatus receives a plurality of ETI frames from the ensemble multiplexing apparatus, and extracts the sending time data constructed in the TIST field of each of the plurality of ETI frames. Next, the transmitting apparatus sequentially sends the plurality of transmission frames according to the sending time data of the transmission frames. In this case, the transmitting apparatus sends the first transmission frame and the second transmission frame having the same sending time data at the same point of time (S560).
[63] Hereinafter, a frame multiplexing apparatus, which constructs the same sending time data in the TIST field of each of two or more ETI frames including different service streams for the same service, will be described.
[64] A frame multiplexing apparatus according to an exemplary embodiment of the present invention includes: a plurality of buffers that temporarily store a plurality of service streams, which are received through different networks; a plurality of time information extractors that extract service time data from the individual service streams stored in the buffers; and a plurality of frame generators that generate ETI frames including at least one service stream output from the buffers according to a sequence of the service time data. In this case, the plurality of frame generators independently generate the ETI frames. [65] FIG. 6 is a block diagram showing a frame multiplexing apparatus according to an exemplary embodiment of the present invention. In FIG. 6, a frame multiplexing apparatus, which includes two buffers, two time information extractors that extract the service time data of the service streams stored in the buffers, and two frame generators, is shown.
[66] The frame multiplexing apparatus according to an exemplary embodiment of the present invention includes a first buffer 611, a second buffer 612, a first time information extractor 621, a second time information extractor 622, a time comparator 630, a first buffer output controller 641, a second buffer output controller 642, a first frame generator 651, a second frame generator 652, a time stamp (TIST) generator 660, and a global positioning system (GPS) receiver 670.
[67] The first buffer 611 temporarily stores the first service stream S610 received through the network, and the second buffer 612 temporarily stores the second service stream S620 received through the network. In this case, it is assumed that the first service stream S610 and the second service stream S620 are multiplexed to different ensembles.
[68] The first time information extractor 621 outputs service time data of the first service stream S610 (hereinafter referred to as "first service time data") stored in the first buffer 611. The second time information extractor 622 outputs service time data of the second service stream S620 (hereinafter referred to as "second service time data") stored in the second buffer 612. In this case, the first time information extractor 621 and the second time information extractor 622 extract the first service time data and the second service time data at the same position of the first buffer 611 and the second buffer 621, respectively.
[69] The time comparator 630 compares the first service time data with the second service time data. In this case, the time comparator 630 determines the points of time at which the first service stream and the second service stream are correspondingly output from the buffers, according to the sequence of the first service time data and the second service time data.
[70] That is, if the first service time data is earlier than the second service time data, the second service stream S620 is output from the second buffer 612 earlier than the first service stream S610 from the first buffer 611. Specifically, the time comparator 630 sets a time (hereinafter referred to as "first buffer output delay time") for which the first service stream S610 is temporarily stored in the first buffer 611 and a time (hereinafter referred to as "second buffer output delay time") for which the second service stream S620 is temporarily stored in the second buffer 612, such that the second service stream S620 is output earlier than the first service stream S610. In this case, the second buffer output delay time is smaller than the first buffer output delay time so that the first service stream and the second service stream having the same service time data are correspondingly output from the buffers later. For example, according to the first and second buffer output delay times, outputting the second service stream from the second buffer may be continuously performed and outputting the first service stream from the first buffer may be hold until a second service stream having the same service time data as the first service stream is received.
[71] Meanwhile, if the second service time data is earlier than the first service time data, the time comparator 630 sets such that the first buffer output delay time is smaller than the second buffer output delay time. That is, the time comparator 630 sets the first buffer output delay time and the second buffer output delay time such that the first service stream S610 is output earlier than the second service stream S620. Accordingly, the first service stream and the second service stream having the same service time data are correspondingly output from the buffers later.
[72] If the first service time data and the second service time data are identical to each other, the time comparator 630 sets the first buffer output delay time and the second buffer output delay time such that the first buffer output delay time is the same as the second buffer output delay time. That is, the first service stream S610 is output from the first buffer 611 at the same time the second service stream S620 is output from the second buffer 612.
[73] The first buffer output controller 641 controls the output of the first service stream
S610 from the first buffer 611 according to the first buffer output delay time. The second buffer output controller 642 controls the output of the second service stream S620 from the second buffer 612 according to the second buffer output delay time. In this case, the first buffer output controller 641 and the second buffer output controller 642 are independently driven. A point of time at which the first service stream S610 is output and a point of time at which the second service stream S620 is output may be identical to or different from each other.
[74] The first frame generator 651 generates the first ETI frame including the first service stream S610 output to the first buffer 611 under the control of the first buffer output controller 641, and outputs the generated first ETI frame to the network. The second frame generator 652 generates the second ETI frame including the second service stream S620 output from the second buffer 612 under the control of the second buffer output controller 642, and outputs the generated second ETI frame to the network. In this case, the first frame generator 651 and the second frame generator 652 are independently driven.
[75] The time stamp (TIST) generator 660 generates the first sending time data and the second sending time data using the standard time. The first sending time data generated in the above-described manner is supplied to the first frame generator 651 and con- structed in the TIST field of the first ETI frame. The second sending time data is supplied to the second frame generator 652 and constructed in the TIST field of the second ETI frame. Here, the first sending time data and the second sending time data are generated in consideration of the time (delay time) for which the transmission frame is transmitted from the ensemble multiplexing apparatus to the each transmitting apparatus.
[76] As shown in FIG. 6, the standard time can be obtained by a global positioning system
(GPS) receiver 670, which acquires information about accurate time from at least three satellites. In FIG. 6, a case where the standard time is obtained using the GPS receiver has been illustrated. However, the present invention is not limited thereto. Any method may be applied to the present invention insofar as it can obtain the standard time.
[77] As described above, according to the frame multiplexing apparatus, with regard to a plurality of ETI frames including a plurality of service streams for any service, the same sending time data is constructed in the TIST field of each of the plurality of ETI frames. Accordingly, the transmitting apparatus checks the frame sending time data constructed in the TIST field of the ETI frame transmitted from the ensemble multiplexing apparatus, and sends the transmission frame. Hereinafter, a transmitting apparatus that can send two or more transmission frames will be described. A transmitting apparatus according to an exemplary embodiment of the present invention includes a plurality of RF signal transmitters.
[78] FIG. 7 is a diagram showing a transmitting apparatus according to an exemplary embodiment of the present invention. In FIG. 7, a frame synchronization transmitting apparatus, which only includes two RF transmitters for receiving two different transmission frames, is shown. Here, the term "RF" means radio frequency.
[79] As shown in FIG. 7, the frame synchronization transmitting apparatus includes a first
RF signal transmitter 711, a second RF signal transmitter 712, and a GPS receiver 720.
[80] The first RF signal transmitter 711 and the second RF signal transmitter 712 individually receive different ETI frames. Then, each transmitter checks the TIST field of the received ETI frame and determines the sending time of the transmission frame.
[81] The GPS receiver 720 is used to obtain the standard time for recognizing the frame sending time data, which is constructed in the TIST field of the received ETI frame.
[82] The operation of the frame synchronization transmitting apparatus shown in FIG. 7 will be described below. The first RF transmitter 711 receives the first ETI frame, which is transmitted from the ensemble multiplexing apparatus shown in FIG. 6, and sends the first transmission frame according to the frame sending time data, which is recognized using the TIST field of the first ETI frame and the standard time obtained by the GPS receiver 720. The second RF transmitter 712 receives the second ETI frame, which is transmitted from the ensemble multiplexing apparatus, and sends the second transmission frame according to the frame sending time data, which is recognized using the TIST field of the second ETI frame and the standard time obtained by the GPS receiver 720.
[83] In this case, when the same frame sending time data is constructed in the TIST field of the first ETI frame and the TIST field of the second ETI frame, the first RF transmitter 711 and the second RF transmitter 712 send the first transmission frame and the second transmission frame at the same point of time, respectively.
[84] Since the first RF signal transmitter 711 and the second RF signal transmitter 712 are independently driven, they may send the terrestrial DMB signals with different modulation frequencies. Though not shown in FIG. 7, the first RF signal transmitter 711 and the second RF signal transmitter 712 may be provided in an RF signal transmitter (not shown). In this case, the RF signal transmitter (not shown) may send signals having the same TIST field value among the RF signals having the same frequency bandwidth at the same point of time by a transmitting method such as layered modulation.
[85] As described above, according to the embodiment of the present invention, a plurality of ETI frames including a plurality of service streams for any service can be simultaneously sent, without constructing an additional field so as to send two or more transmission frames at the same point of time. Accordingly, the receiving apparatus receives a plurality of transmission frames including service streams for the same service at substantially the same point of time. Therefore, a large-capacity buffer does not need to be provided, and it does not take a lot of time to decode the service.
[86] The embodiment of the present invention described above is not only implemented by the method and apparatus, but may be implemented by a program for executing the functions corresponding to the configuration of the exemplary embodiment of the present invention or a recording medium having the program recorded thereon. These implementations can be realized by the ordinarily skilled person in the art from the description of the above-described exemplary embodiment.
[87] While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

Claims
[1] An apparatus for multiplexing a frame, the apparatus comprising: a first buffer that stores a first service stream transmitted from the outside; a second buffer that stores a second service stream transmitted from the outside; a time comparator that compares first service time data about the first service stream with second service time data about the second service stream; a first frame generator that outputs a first frame including the first service stream output from the first buffer; a second frame generator that outputs a second frame including the second service stream output from the second buffer; and a time stamp generator that generates first sending time data to be constructed in a time stamp field of the first frame and second sending time data to be constructed in a time stamp field of the second frame, wherein, if the first service time data and the second service time data are identical to each other, the time stamp generator generates the first sending time data and the second sending time data as the same data.
[2] The apparatus of claim 1, wherein the first sending time data is used to determine a point of time to send the first frame, and the second sending time data is used to determined a point of time to send the second frame.
[3] The apparatus of claim 1, wherein, if the first service time data and the second service time data are identical to each other, the time comparator synchronizes a point of time at which the first buffer outputs the first service stream with a point of time at which the second buffer outputs the second service stream.
[4] The apparatus of claim 1, further comprising a global positioning system (GPS) receiver that receives a standard time for generating the first sending time data and the second sending time data from at least one satellite.
[5] The apparatus of claim 1, further comprising: a first buffer output controller that controls the output of the first service stream according to a sequence of the first service time data and the second service time data; and a second buffer output controller that controls the output of the second service stream according to the sequence.
[6] The apparatus of claim 1, further comprising: a first time information extractor that recognizes the first service time data from the first service stream; and a second time information extractor that recognizes the second service time data from the second service stream.
[7] A method of multiplexing frames, the method comprising: storing, in a first buffer and a second buffer, a plurality of service streams including a first service stream and a second service stream from the outside; detecting service time data of each of the plurality of service streams; comparing a plurality of service time data corresponding to the plurality of service streams with each other; generating a first frame including the first service stream; generating a second frame including the second service stream; and if first service time data corresponding to the first service stream stored in the first buffer is identical to second service time data corresponding to the second service stream stored in the second buffer, generating first sending time data to be constructed in a time stamp field of the first frame and second sending time data to be constructed in a time stamp field of the second frame as the same data.
[8] The method of claim 7, further comprising, if the first service time data and the second service time data are identical to each other, outputting the first service stream and the second service stream at the same point of time.
[9] The method of claim 8, further comprising setting a time at which the first service stream is maintained in the first buffer and a time at which the second service stream is maintained in the second buffer, such that the first service stream and the second service stream are output at the same point of time.
[10] The method of claim 7, further comprising, if the first service time data and the second service time data are identical to each other, generating the first frame and the second frame at the same point of time.
[11] The method of claim 9, further comprising outputting a plurality of frames corresponding to the plurality of service streams according to a sequence of the plurality of service time data.
[12] A transmitting apparatus, comprising: a first transmitter that receives a first frame from the outside, and sends the first frame according to first sending time data in a time stamp field of the first frame; and a second transmitter that receives a second frame from the outside, and sends the second frame according to second sending time data in a time stamp field of the second frame, wherein the first transmitter and the second transmitter are independently driven.
[13] The transmitting apparatus of claim 12, wherein, if the first sending time data and the second sending time data are identical to each other, a point of time at which the first transmitter sends the first frame is identical to a point of time at which the second transmitter sends the second frame. [14] The transmitting apparatus of claim 12, further comprising a GPS receiver that receives a standard time for recognizing the first sending time data and the second sending time data from at least one satellite. [15] The transmitting apparatus of claim 12, wherein the first transmitter and the second transmitter send signals with different modulation frequencies. [16] The transmitting apparatus of claim 12, wherein the first transmitter and the second transmitter send signals with the same modulation frequency by a transmitting method such as layered modulation.
EP08766459.5A 2007-06-20 2008-06-19 DIGITAL BROADCASTING SIGNAL TRANSMISSION FRAME MULTIPLEXING METHOD, TRANSMISSION FRAME MULTIPLEXING APPARATUS, AND TRANSMITTING APPARATUS Withdrawn EP2160861A4 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
KR20070060329 2007-06-20
KR1020070108780A KR101382613B1 (en) 2007-06-20 2007-10-29 Method of multiplexing transmission frame, apparatus of multiplexing transmission frame and transmission apparatus for digital broadcasting signal
PCT/KR2008/003499 WO2008156326A2 (en) 2007-06-20 2008-06-19 Method of multiplexing transmission frame of digital broadcasting signal, apparatus for multiplexing transmission frame, and transmitting apparatus

Publications (2)

Publication Number Publication Date
EP2160861A2 true EP2160861A2 (en) 2010-03-10
EP2160861A4 EP2160861A4 (en) 2013-05-01

Family

ID=40370099

Family Applications (1)

Application Number Title Priority Date Filing Date
EP08766459.5A Withdrawn EP2160861A4 (en) 2007-06-20 2008-06-19 DIGITAL BROADCASTING SIGNAL TRANSMISSION FRAME MULTIPLEXING METHOD, TRANSMISSION FRAME MULTIPLEXING APPARATUS, AND TRANSMITTING APPARATUS

Country Status (4)

Country Link
EP (1) EP2160861A4 (en)
KR (1) KR101382613B1 (en)
CN (1) CN101715637B (en)
WO (1) WO2008156326A2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102215499B (en) * 2010-04-01 2013-08-14 鼎桥通信技术有限公司 Method for determining occurrence time of measurement event

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100233937B1 (en) * 1996-10-17 1999-12-15 이계철 Video and audio synchronization method using timestamp compensation and mpeg-2 encoder
SE0201008D0 (en) * 2002-04-03 2002-04-03 Teracom Ab A method and a system for synchronizing digital data streams
KR100646851B1 (en) * 2004-11-03 2006-11-23 한국전자통신연구원 Terrestrial digital multimedia broadcasting transmission / reception system for synchronization of audio / video services and data services
WO2006126852A1 (en) * 2005-05-26 2006-11-30 Electronics And Telecommunications Research Institute Method and apparatus for synchronizing data service with video service in digital multimedia broadcasting
KR100713665B1 (en) * 2005-07-18 2007-05-02 주식회사 쏠리테크 Terrestrial DMB Broadcasting System and Method Using Satellite Path and Frame Composition Method therefor
CN100589370C (en) * 2006-09-15 2010-02-10 中兴通讯股份有限公司 A Synchronous Transmission Method of a Mobile Multimedia Broadcast Transmission System

Also Published As

Publication number Publication date
KR101382613B1 (en) 2014-04-07
CN101715637B (en) 2013-04-03
CN101715637A (en) 2010-05-26
WO2008156326A2 (en) 2008-12-24
WO2008156326A3 (en) 2009-02-26
EP2160861A4 (en) 2013-05-01
KR20080112072A (en) 2008-12-24

Similar Documents

Publication Publication Date Title
US10938511B2 (en) Apparatus for transmitting broadcast signal, apparatus for receiving broadcast signal, method for transmitting broadcast signal and method for receiving broadcast signal
US11516556B2 (en) Apparatus for transmitting broadcast signal, apparatus for receiving broadcast signal, method for transmitting broadcast signal and method for receiving broadcast signal
JP7120369B2 (en) Transmission device and transmission method
US11032200B2 (en) Apparatus for transmitting broadcast signal, apparatus for receiving broadcast signal, method for transmitting broadcast signal and method for receiving broadcast signal
US11601210B2 (en) Broadcasting signal transmission apparatus, broadcasting signal receiving apparatus, broadcasting signal transmission method and broadcasting signal receiving method
US10728306B2 (en) Apparatus for transmitting broadcast signal, apparatus for receiving broadcast signal, method for transmitting broadcast signal and method for receiving broadcast signal
US10903922B2 (en) Apparatus for transmitting broadcast signal, apparatus for receiving broadcast signal, method for transmitting broadcast signal and method for receiving broadcast signal
US20210084092A1 (en) Apparatus and method for transmitting or receiving broadcast signal
US10681426B2 (en) Apparatus for transmitting broadcast signal, apparatus for receiving broadcast signal, method for transmitting broadcast signal and method for receiving broadcast signal
CA2918693A1 (en) Method and apparatus for transmitting a broadcast signal
US10237630B2 (en) Method and system for transmitting satellite signals and receiver thereof
US10721505B2 (en) Broadcast signal transmission apparatus, broadcast signal reception apparatus, broadcast signal transmission method, and broadcast signal reception method
KR100941758B1 (en) Frame Multiplexing Method and Apparatus for Digital Multimedia Broadcasting
EP2160861A2 (en) Method of multiplexing transmission frame of digital broadcasting signal, apparatus for multiplexing transmission frame, and transmitting apparatus
WO2009020302A2 (en) System and method for digital multimedia broadcasting
KR20160108071A (en) Apparatus and method for transmitting and receiving digital radio broadcating service

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20100120

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA MK RS

DAX Request for extension of the european patent (deleted)
A4 Supplementary search report drawn up and despatched

Effective date: 20130404

RIC1 Information provided on ipc code assigned before grant

Ipc: H04H 60/07 20080101ALI20130327BHEP

Ipc: H04H 60/06 20080101ALI20130327BHEP

Ipc: H04L 7/02 20060101AFI20130327BHEP

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20160304