JP4797088B2 - Transmission / reception system and transmission / reception method - Google Patents

Description

  The present invention relates to a technology of a digital broadcasting service with different transport stream multiplexing systems in satellite or terrestrial digital broadcasting such as CS and BS.

  Regarding digital transmission of CATV, the Television Society Technical Report (vol. 19, No. 42) published on September 21, 1995, pages 19 to 24, “Telecommunication Technology Council Provisional System Digital Cable Television Broadcasting” It is shown in "Transmission experiment". According to this report, a data stream of a format called a transport stream (hereinafter referred to as TS) in which digital data such as an image compressed by a digital image compression technique called MPPEG 2 (MPEG2) is multiplexed is obtained. It is subjected to signal processing such as error correction, modulated by a digital modulation technique called 64QAM (64-value quadrature amplitude modulation), and transmitted to a CATV transmission line with a transmission capacity of about 30 Mbps.

  Also, CS digital broadcasting is a multi-channel digitized video distribution method used as an input for digital CATV. Regarding the broadcasting, a paper “Nearly 70” was published on page 149 of the Nikkei Electronics September 2, 1996 issue. As described in "Japan's first digital satellite broadcasting that realizes multi-channel", a single TS that is packet-multiplexed with multiple digitally compressed (MPEG2) programs and data, scrambled, and corrected and encoded is QPSK. Transmit with digital modulation. A remultiplexing apparatus that remultiplexes digital data composed of a plurality of bit streams such as a digital broadcasting service using a single TS is disclosed in Japanese Patent Laid-Open No. 10-41909. According to this publication, it is shown that a single TS is composed of 188-byte TS packets, and that the TS packet is composed of 184-byte packet data and a 4-byte packet header. By re-editing and transmitting the program control information and the like, it is possible to simultaneously receive TSs from a plurality of broadcasters at the receiving terminal.

  On the other hand, in the newly planned BS digital broadcasting, a plurality of digitized broadcasts are transmitted to one transmission channel of the conventional BS analog broadcast, and not only the conventional standard television broadcast but also the high-definition television broadcast. Is also planned to be transmitted. The transmission of BS digital broadcasting is described in “BS Digital Broadcasting System and Equipment” on pages 24 to 31 of the Journal of the Video Media Society (vol. 52 No. 11 1998) in November 1998. In BS digital broadcasting, using a transmission capacity of about 60 Mbps, multiple modulation systems can be used in one repeater, and multiple TSs can be transmitted by providing a frame configuration for video, audio, data, etc. Enable and send new data formats. In this data format, a transmission multiplex control signal (hereinafter referred to as a TMCC signal) is used for transmission of control information in a modulation scheme within a frame and a configuration of a plurality of TSs. The TMCC signal is divided and transmitted frame by frame (= 48 slots, 1 slot = 204 bytes) before the main signal using the synchronization signal portion of the TS from the Ministry of Posts and Telecommunications Order No. 57, and 1 superframe (= 8 frames). ) As a period. The structure is shown in Ministry of Posts and Telecommunications Notification No. 260, the transmission mode / slot information is used for selecting the digital demodulation means, and the relative TS / slot information and the relative TS / TSID correspondence are the selection of the ID (TSID) of the desired TS. Used for output. In addition, there are transmission / reception control information such as a change instruction number and emergency information, and an extended information area.

  In the above-mentioned conventional digital CATV technology, transmission and reception of a plurality of TS transmissions planned for BS digital broadcasting are not taken into consideration. Therefore, the Technical Report of the Institute of Image Information and Television Engineers published on July 27, 1999 (vol. 23, No. 48), “Proposal for Multiple Cable-Multiple MPEG-TS Multiplexing System” on pages 7 to 12 and “Multi-MPEG-TS Cable TV Transmission Experiment” on pages 13 to 18 of the same report. Proposals have been made. In these reports, a TSMF header is proposed in which N 188-byte TS packets are collected to form a multiplexed frame, and in-frame TS arrangement information is described in the first packet. With this proposal, it is possible to efficiently transmit a plurality of BS digital broadcast TS signals to a cable television.

Japanese Patent Laid-Open No. 10-41909

ITEJ Technical Report (vol.19, No.42) Nikkei Electronics September 2nd, 1996, page 149, "Japan's first digital satellite broadcasting that realizes nearly 70 channels" Journal of the Video Media Society of November 1998 (vol. 52 No. 11 1998) ITE Technical Report (vol.23, No.48)

  In the above-described prior art, for example, in a receiving apparatus that receives a broadcasting service by a single TS that retransmits CS digital broadcasting through a CATV transmission path, a plurality of TSs that retransmit a plurality of TSs such as a newly planned BS digital broadcasting. The transmission system is not supported, and it is impossible to receive the BS digital broadcast CATV retransmission service.

  In addition, although a CATV retransmission transmission method corresponding to a plurality of TSs such as BS digital broadcasting is shown, in the case where a single CS digital broadcasting TS and a plurality of BS digital broadcasting TSs are serviced together in CATV. The handling method of the receiving device has not been considered.

  The problem of the present invention is that when a CS digital broadcast having a single transport stream and a BS digital broadcast having a plurality of transport streams are mixed and transmitted to a CATV transmission line, a single TS and a plurality of TSs are transmitted. An object of the present invention is to provide a receiving apparatus that can handle both transmission methods.

  In order to solve the above-mentioned problem, a digital retransmission broadcast of a cable television which selects digital data in a transport stream format from the digital broadcast and transmits the digital data in accordance with a digital transmission data rate of the cable television, wherein the transport stream A plurality of transport stream (hereinafter referred to as a plurality of TS) transmission method means for transmitting a plurality of digital data in a format and a single transmission for multiplexing and transmitting the digital data in the transport stream format in one transport stream A receiver for a cable television, which includes a transport stream (hereinafter referred to as a single TS) transmission method means, and receives a digital retransmission broadcast of a cable television in which the plurality of TSs and the single TS are mixedly transmitted. In the multiple TS transmission method, TS comprises means for detecting the presence or absence of a frame header packet including multiple information and the plurality TS transmission scheme as the single TS transmission method and the determination cable TV receiver including a determination means for performing.

  According to the present invention, it is possible to provide a receiving apparatus that contributes to providing a CATV broadcast service in which a plurality of TSs and a single TS are mixed in a CATV digital broadcast service.

It is a block diagram which shows the structural example of the digital broadcast re-transmission service of the cable television which is one Embodiment of this invention. It is a figure which shows the structural example of single TS and multiple TS of one Embodiment of this invention. It is a figure which shows the example of a frame structure of multiple TS of one Embodiment of this invention. It is a figure which shows the structural example of the frame header of multiple TS of one Embodiment of this invention. It is a block diagram which shows the structural example of the receiver of one Embodiment of this invention. It is a figure which shows the example of a processing flow which discriminate | determines multiple TS and single TS in the receiver of one Embodiment of this invention.

  Embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a system configuration diagram in a case where a plurality of TSs and a single TS transmission system of a cable television according to an embodiment of the present invention are mixedly transmitted. In FIG. 1, 100 is a center station equipment, 101 is a BS digital receiving antenna, 102 is a BS digital signal transmission cable, 103 to 106 are BS tuners for stations, 107 and 108 are TS multiplexers, 109, 110 and 118 are QAM modulations 111, CS digital receiving antenna, 112 CS digital signal transmission cable, 113 to 116 CS tuner for station, 117 program multiplexer, 119 mixer, 120 CATV transmission path, 121 CATV subscriber home , 122 is a receiving device, and 123 is a TV monitor. According to the present embodiment, the BS digital broadcast service is received by the BS digital receiving antenna 101 at the CATV center station, and is distributed to the BS tuners 103 to 106 for the station by the transmission cable 102. The station BS tuners 103 to 106 extract one designated TS from among a plurality of TSs multiplexed and input the TSs to the TS multiplexers 107 and 108. The TS multiplexers 107 and 108 re-multiplex the transport stream input from the station BS tuners 103 to 106 and perform speed conversion so as to match the CATV transmission speed. In addition, when a plurality of TSs to be described later have a frame configuration, a frame header packet including slot allocation information is inserted and output to the QAM modulators 109 and 110. The QAM modulators 109 and 110 modulate a plurality of input TSs into multilevel digital modulation and a predetermined carrier frequency.

  On the other hand, the CS digital broadcast received by the CS digital receiving antenna 111 is distributed to the station CS tuners 113 to 116 by the transmission cable 112. The station CS tuners 113 to 116 select a program to be retransmitted, and output a transport stream packet of the selected program to the program multiplexer 117. The program multiplexing device 117 multiplexes the input transport stream packets to generate one transport stream. Further, the packet ID is replaced as necessary, and the speed is converted to match the CATV transmission speed. A program-multiplexed single TS is input to a QAM modulator 118, where it is modulated into multilevel digital modulation and a predetermined carrier frequency. The modulated CS digital retransmission signal and the BS digital retransmission signal described above are frequency-multiplexed by the mixer 119 and output to the CATV transmission line 120. At the subscriber home 121 connected to the CATV transmission path 120, the receiving device 122 receives the CATV broadcast, selects the serviced program, and views the playback screen on the TV monitor 123 or the like.

  In this embodiment, the CATV retransmission of BS digital broadcasting is shown in two lines, and the CATV retransmission of CS digital broadcasting is shown in one line, but this number varies depending on the service contents. Also, the number of TS remultiplexes for BS digital broadcasts and the number of program remultiplexes for CS digital broadcasts are not limited. Further, the present invention includes a method in which a terrestrial digital broadcast scheduled to be broadcast in the future is received by the center station and retransmitted by CATV.

  FIG. 2 shows a configuration example of a transport stream of a single TS and a plurality of TSs. FIG. 6A shows the configuration of a single TS 201 in the case of CS digital retransmission, and transport stream packets of programs 1 to 4 (202 to 205) selected by the CS tuners for stations 113 to 116 are time axes. It is multiplexed. The arrangement of transport stream packets is not regular, but depends on the information amount of each program to be multiplexed. FIG. 6B shows the structure of a plurality of TSs 209 in the case of BS digital retransmission, in which the transport streams (TS1 and TS2 (210, 211) in the example in the figure) extracted by the station BS tuners 103 to 106 are time axes. It is multiplexed. In addition, the arrangement of TSs is allocated to slots according to the information amount of each TS and the frame configuration described later.

  FIG. 3 is a frame configuration diagram showing a frame configuration of a plurality of TS transport stream packets. In a plurality of TSs, a frame header packet 301 in units of 188 bytes and n packets constitute one frame, and each TS is allocated according to the amount of data in the n packets. The payload area of the frame header packet 301 includes packet allocation information, TS_ID of the allocated transport stream, TS reception status, and the like. A conceptual diagram of the frame header packet 301 is shown in FIG.

  The frame header packet 301 has a 4-byte TS packet header 402 followed by a payload 405 area. The payload 405 includes the above-described slot assignment information, TS_ID, TS reception status, and the like, and is transmitted. The value of 47H is written in the area of the sync byte 403 at the head of the TS packet header 402, and the head of the TS packet is detected by searching for this value. The TS packet header 402 includes a packet ID 404 area, and a unique packet ID (hereinafter referred to as PID) value is assigned to the frame header packet 301. By searching the PID of the frame header packet 301, the frame header packet 301 can be detected from the transport stream in which a plurality of TSs are multiplexed. The frame header packet 301 is generated and added by the TS multiplexers 107 and 108.

  FIG. 5 is a block diagram illustrating an internal configuration of the receiving device 122 according to the embodiment of this invention. In the figure, 502 is an RF input terminal, 503 is a tuner, 504 is a QAM demodulator, 505 is a TS separator, 506 is a demultiplexer, 507 is an MPEG decoder, 508 is a video signal DAC, 509 is a video signal NTSC converter, 510 is a CPU, 511 is a bus line, 512 is an audio signal DAC, 513 is a high-definition video output terminal, 514 is an NTSC video output terminal, and 515 is an audio output terminal. The frequency-multiplexed CATV signal is input from the transmission line 120 to the tuner 503 via the RF input terminal 502. The tuner 503 selects the frequency, and then the QAM demodulator 504 demodulates the digital modulated wave. The demodulated digital signal is input to the TS separator 505. In the case of a plurality of TSs in this TS separation unit 505, one designated transport stream is selected and output. In the case of a single TS, through output is performed as it is. The TS separation unit 505 determines a plurality of TSs and a single TS, which is a feature of the present invention, and notifies the CPU 510 that controls the receiving device 122. This determination of multiple TSs and single TSs is performed, for example, when initialization is performed when the receiving device 122 is turned on or when the channel selection frequency is changed. The output of the TS separation unit 505 is input to the demultiplexer 506, and information related to the program selected by the viewer or the like is filtered from the transport stream, and the video signal or audio signal digitally compressed to the MPEG system Is input to the MPEG decoder 507. The MPEG decoder 507 decompresses the digitally compressed video signal or audio signal, the video signal is output to the high-speed video signal DAC 508 and the NTSC converter 509, and the audio signal is output to the audio signal DAC 512. The video signal DAC 508 converts the input digital video signal into an analog high-definition video signal and outputs it to the high-definition video output terminal 513. The NTSC converter 509 down-converts the digital video signal, converts it to an NTSC video signal, and outputs it to the NTSC video output terminal 514. The audio signal DAC 512 converts the audio signal from a digital signal to an analog signal and outputs it to the audio output terminal 515. By connecting a TV monitor 123 or the like to these output terminals, the viewer can watch the program. Each of these blocks is connected to the CPU 510 by a bus line 511, and a series of controls are performed by the CPU 510.

  Next, an embodiment of a method for discriminating between a plurality of TSs and a single TS of the TS separator 505, which is a feature of the present invention, will be described.

  FIG. 6 is a processing flow for explaining an example of a method for discriminating between a plurality of TSs and a single TS in the TS separation unit 505. First, at 601 all loop counters are cleared to zero. Next, at 602, a sync byte value 47H indicating the head of the transport stream packet is detected. When 47H is detected, one transport stream packet is skipped at 603, and it is determined at 604 whether the value is 47H again. If the determination result is NO (N in the figure) at 604, it is determined that it is not the top of the transport stream packet, and the process returns to the top of the process 601 again. If the determination is YES (Y in the figure), it is determined at 605 whether the counter 1 has looped a predetermined number of times (N1 times). If the number of loops has not reached N1 (N), the counter 1 is incremented by one at 606 and the process returns to the top of 603. When the counter 1 matches N1 (Y), the process proceeds to 607, and the PID of the transport stream packet is acquired. By detecting 47H which is the head of the transport stream packet continuously N1 times by the above processing, the head of the packet can be selected from the continuous transport stream. Note that the value of the loop count N1 is an arbitrary value. Increasing the value improves the reliability of packet head detection, but 3 to 5 times is appropriate because the processing time becomes longer. After acquiring the PID of the transport stream packet in 607, it is determined whether or not the acquired PID is a frame header PID of a plurality of TSs in 608. If the PID is not the frame header PID (N), the loop counter 2 is incremented by 1 at 609. Next, at 610, it is determined whether or not the number of loops of the counter 2 has reached N2. The value of N2 is set to be equal to or greater than the number of packets for one frame constituting a plurality of TSs. If the counter 2 has not reached the number of times N2 (N), at 611, one transport stream packet is skipped, and the process returns to the beginning of 607 to obtain the next PID. When the counter 2 reaches the number N2 (Y), the process proceeds to 619 and the frame header packet 301 included in the plurality of TSs does not exist in the transport stream packet, so that it is determined as a single TS, and the CPU 510 is notified. Do. As a means for notifying the CPU 510, a method using a general-purpose I / O port or a method of transmitting data using the bus line 511 can be considered. If it matches with the frame header PID at 608 (Y), the counter 3 is incremented by 1 at 612, one frame is skipped at 613, and the PID is acquired again at 614. Next, it is determined whether or not the PID acquired in 615 matches the frame header PID. If it does not match the frame header PID (N), the counter 2 and the counter 3 are cleared at 616 and the process returns to the top of 607. If it matches with the frame header PID (Y), it is determined at 617 whether or not the counter 3 matches the loop count N3. When the value of the counter 3 does not match N3 (N), the process returns to the top of 612. When the value of the counter 3 coincides with N3 (Y), it is determined as a plurality of TSs in 618, and the CPU 510 is notified. This notification method is the same as that in the case of notifying the single TS described above. The number of loops N3 is an arbitrary value, but if this value is increased, the processing time becomes longer, so a value of 2 to 5 is appropriate.

  By performing the above-described processing in the TS separation unit 505, even if a plurality of TSs and a single TS are mixedly transmitted on the CATV transmission line, the reception device 122 appropriately receives the signals corresponding to the plurality of TSs and the single TS. Can be performed.

  DESCRIPTION OF SYMBOLS 100 ... Center station equipment, 101 ... BS digital receiving antenna, 102 ... Transmission cable, 103-106 ... BS tuner for station, 107, 108 ... TS multiplexer, 109, 110, 118 ... QAM modulator, 111 ... CS digital reception Antenna, 112 ... Transmission cable, 113-116 ... CS tuner for station, 117 ... Program multiplexer, 119 ... Mixer, 120 ... CATV transmission path, 121 ... CATV subscriber's house, 122 ... Receiver, 123 ... TV monitor, 201 ... single TS, 209 ... multiple TS, 301 ... frame header packet, 402 ... TS packet header, 403 ... sync byte, 404 ... packet ID, 405 ... payload, 502 ... RF input terminal, 503 ... tuner, 504 ... QAM Demodulator, 505 ... TS separator, 506 ... demultiplexer, 5 7 ... MPEG decoder, 508 ... video signal DAC, 509 ... NTSC converter, 510 ... CPU, 511 ... bus line, 512 ... audio signal DAC, 513 ... high definition video output terminal, 514 ... NTSC video output terminal, 515 ... audio Output terminal.

Claims (5)

  A transmission device for transmitting a signal in which a plurality of transport streams in which a plurality of transport streams are multiplexed and transmitted and a single transport stream in which digital data is multiplexed in one transport stream;
  Receiving means for receiving a signal transmitted from the transmitting apparatus; demodulating means for demodulating the signal received by the receiving means; and whether the signal demodulated by the demodulating means is a plurality of transport streams or a single transport A receiving apparatus comprising: a separating unit that determines whether the stream is a stream and, in the case of a plurality of transport streams, separates one transport stream included in the plurality of transport streams;
  A transmission / reception system comprising:   The transmission / reception system according to claim 1,
  The receiving apparatus includes decoding means for decoding digital data of a transport stream separated by the separation means or digital data of a single transport stream included in a signal demodulated by the demodulation means. Sending and receiving system. The transmission / reception system according to claim 2,
The transmission / reception system, wherein the receiving device comprises analog conversion means for converting the digital data decoded by the decoding means into analog data.   A transmission step of transmitting a signal in which a plurality of transport streams in which a plurality of transport streams are multiplexed and transmitted and a single transport stream in which digital data is multiplexed in one transport stream;
  A receiving step for receiving the signal transmitted in the transmitting step;
  A demodulation step for demodulating the signal received in the reception step;
  It is determined whether the signal demodulated in the demodulation step is a plurality of transport streams or a single transport stream, and in the case of a plurality of transport streams, one transport stream included in the plurality of transport streams is separated. And a separation step.   Receiving means for receiving digital data transmitted by a cable in which a single transport stream and a plurality of transport streams are mixed;
  Demodulating means for demodulating QAM digital data received by the receiving means;
  Discriminating means for discriminating between the plurality of transport streams and the single transport stream by detecting the presence or absence of a frame header packet of the plurality of transport streams included in the digital data demodulated by the demodulating means;
  When the discriminating means discriminates a single transport stream, it is output as it is. When the discriminating means discriminates a plurality of transport streams, the digital data of one designated transport stream is separated and separated. And a transport stream separating means for outputting the transport stream.

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