JP2014195210A - Broadcast unit, transmission method and broadcast system - Google Patents

Abstract

A technique for efficiently realizing timing synchronization between broadcasting apparatuses is provided.
A first generation unit and a second generation unit generate a plurality of packets to be arranged between acquired frame pulses. The second generation unit 212 includes time difference information between the TOT packet and the reference timing pulse in the TOT packet that is a part of the plurality of packets. The transmission unit 240 transmits the generated plurality of packets to another broadcasting device. The deforming unit 232 deforms some of the generated packets. The transformation unit 232 removes the time difference information from the TOT packet, which is a part of the packet, and inserts error detection data into the TOT packet instead of the time difference information. The broadcast unit 234 broadcasts a plurality of packets obtained by transforming some packets.
[Selection] Figure 3

Description

  The present invention relates to a transmission technique, and more particularly to a broadcasting apparatus, a transmission method, and a broadcasting system that transmit a predetermined signal.

  In the terrestrial digital broadcasting system, MPEG (Moving Picture Coding Experts Group) 2-TS (Transport Stream) is adopted, and OFDM (Orthogonal Frequency Division Multiplexing) is also adopted. Further, in the digital terrestrial broadcasting system, SFN (Single Frequency Network) broadcasting using the same frequency is adopted. In SFN broadcasting, when the transmission distance is different for each transmission path and MPEG2-TS packets are distributed and transmitted to a plurality of transmission stations, the reception characteristics deteriorate when the difference in time at which the radio waves emitted from the transmission stations arrive at the reception point increases. To do. In order to cope with this, the packet indicating the reference time is also multiplexed, and based on this, timing synchronization between transmitting stations is performed (for example, Patent Document 1).

JP 2003-32207 A

  Area one-segment broadcasting (also called one-segment type area broadcasting) uses one-segment broadcasting, which is one of terrestrial digital broadcasting, and is limited to a narrow area with transmission power that is lower than the transmission power used by broadcasters. It is a service that transmits content data. When transmitting signals from a plurality of broadcasting devices in such area one segment broadcasting, timing synchronization between the broadcasting devices is required. In SFN operation in area one-segment broadcasting, installation work for installing a dedicated line is difficult to secure the installation location and financially. For this reason, reference synchronization using a reference signal of another system such as GPS (Global Positioning System) is preferable to a complete synchronization method or a subordinate synchronization method in which data or a clock using a dedicated line is distributed from a master broadcasting device. The reference synchronization is stipulated in the operational guidelines of the terrestrial digital broadcasting standard. In order to synchronize with the GPS 1pps signal, the TS packet of the invalid layer includes the time difference information from the reference time in the TS packet of the invalid layer. Is arranged.

  A broadcasting device for area one segment broadcasting is required to have a cost close to that of consumer equipment and a low running cost. Therefore, it is necessary to transmit MPEG2-TS (hereinafter simply referred to as TS) distributed over the network in a necessary minimum state. Therefore, area one-segment broadcasting uses only TS packets transmitted from a broadcasting device, not a TS remultiplexing format conscious of hierarchical transmission used in full-segment broadcasting and 12-segment broadcasting, which are general terrestrial digital broadcasting. There is no TS packet in the invalid layer. Since there is no invalid layer TS packet, information for synchronizing with the GPS cannot be shared between the broadcasting apparatuses, and timing synchronization is not realized.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a technique capable of efficiently realizing timing synchronization between broadcasting apparatuses.

  In order to solve the above problems, a broadcasting apparatus according to an aspect of the present invention includes an acquisition unit that acquires a reference timing pulse having a predetermined period and a frame pulse having a period different from the period of the reference timing pulse. A generation unit that generates a plurality of TS packets to be arranged between frame pulses acquired by the acquisition unit, a transmission unit that transmits the plurality of TS packets generated by the generation unit to another broadcasting device, and a generation unit A modification unit that transforms a TOT packet among the plurality of TS packets and a broadcast unit that broadcasts a plurality of TS packets including the TOT packet modified by the modification unit as an OFDM signal are provided. The generation unit includes information on a time difference between the TOT packet and the reference timing pulse in a predetermined area of the TOT packet, and the deformation unit removes information on the time difference from the predetermined area of the TOT packet, and instead of the information on the time difference. The error detection data is inserted into a predetermined area of the TOT packet, and the other broadcasting apparatus that has received the plurality of TS packets transmitted by the transmission unit removes the time difference information from the predetermined area of the TOT packet. Instead, error detection data is inserted into a predetermined area of the TOT packet.

  Another embodiment of the present invention is also a broadcasting device. In this apparatus, a reference timing pulse having a predetermined period and a frame pulse having a period different from the period of the reference timing pulse are defined, and a plurality of TS packets arranged between the frame pulses are transmitted through OFDM. A receiving unit that receives signals from other broadcasting devices as a signal, a deforming unit that modifies a TOT packet among a plurality of TS packets received by the receiving unit, and a plurality of TS packets in which the deforming unit modifies the TOT packet as an OFDM signal. And a broadcasting section for broadcasting. The predetermined area of the TOT packet among the plurality of TS packets received by the receiving unit includes information on the time difference between the TOT packet and the reference timing pulse, and the deforming unit displays the information on the time difference from the predetermined area of the TOT packet. In addition to the removal, error detection data is inserted into a predetermined area of the TOT packet instead of the time difference information, and the broadcasting unit broadcasts a plurality of TS packets as OFDM signals according to the time difference information.

  Yet another embodiment of the present invention is a transmission method. This method includes a step of acquiring a reference timing pulse having a predetermined period and a frame pulse having a period different from the period of the reference timing pulse, and a plurality of TS packets to be arranged between the acquired frame pulses. Generating a plurality of TS packets, a step of transmitting a plurality of generated TS packets to another broadcasting device, a step of modifying a TOT packet among the generated plurality of TS packets, and a plurality of TS packets obtained by modifying the TOT packet Broadcasting as an OFDM signal. The generating step includes information on the time difference between the TOT packet and the reference timing pulse in a predetermined region of the TOT packet among the plurality of TS packets, and the step of modifying removes the information on the time difference from the predetermined region of the TOT packet. In addition, the error detection data is inserted into the predetermined area of the TOT packet instead of the time difference information, and the transmission step receives the plurality of TS packets transmitted from the predetermined area of the TOT packet. The information is removed and error detection data is inserted into a predetermined area of the TOT packet instead of the time difference information.

  Yet another embodiment of the present invention is also a transmission method. In this method, a reference timing pulse having a predetermined period and a frame pulse having a period different from the period of the reference timing pulse are defined, and a plurality of TS packets arranged between the frame pulses are transmitted by OFDM. Receiving as a signal from another broadcasting device, transforming a TOT packet among the received TS packets, and broadcasting a plurality of TS packets modified from the TOT packet as OFDM signals. The predetermined region of the TOT packet among the plurality of TS packets received by the receiving step includes information on the time difference between the TOT packet and the reference timing pulse, and the step of modifying the time difference from the predetermined region of the TOT packet In the step of removing information and inserting error detection data into a predetermined area of the TOT packet instead of the time difference information and broadcasting, a plurality of TS packets are broadcast as OFDM signals according to the time difference information.

  Yet another embodiment of the present invention is a broadcasting system. This broadcasting system acquires a reference timing pulse having a predetermined cycle and a frame pulse having a cycle different from the cycle of the reference timing pulse, and a plurality of TS packets to be arranged between the acquired frame pulses. After the generation, the plurality of generated TS packets are transmitted to the slave broadcasting device, and the TOT packet of the generated plurality of TS packets is transformed and broadcast as an OFDM signal, and received from the main broadcasting device A slave broadcast device that transforms the TOT packet of the plurality of TS packets and broadcasts it as an OFDM signal. The main broadcast device includes (1) information on a time difference between the TOT packet and a reference timing pulse in a predetermined area of the TOT packet among a plurality of TS packets for transmission, and (2) a TOT packet for broadcast. The time difference information is removed from the predetermined area, and error detection data is inserted into the predetermined area of the TOT packet in place of the time difference information. The slave broadcasting device (1) obtains the time difference information from the predetermined area of the TOT packet. At the same time, error detection data is inserted into a predetermined area of the TOT packet instead of the time difference information, and (2) a plurality of TS packets are broadcast as OFDM signals according to the time difference information.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, it is possible to efficiently realize timing synchronization between broadcasting apparatuses.

It is a figure which shows the structure of the area one segment broadcast system which concerns on the Example of this invention. FIGS. 2A to 2D are diagrams showing timings in the area one segment broadcasting system of FIG. It is a figure which shows the structure of the main broadcast apparatus of FIG. FIGS. 4A and 4B are diagrams showing a format of a TOT packet generated in the main broadcast apparatus of FIG. It is a figure which shows the structure of the slave broadcasting apparatus of FIG. It is a sequence diagram which shows the broadcast procedure by the area one segment broadcast system of FIG.

  Before describing the present invention specifically, an outline will be given first. An embodiment of the present invention relates to an area one segment broadcasting system for transmitting an OFDM signal including content data in order to realize a content distribution service in area one segment broadcasting. The area one segment broadcasting system includes a plurality of broadcasting devices, and signals broadcast from them are received by a receiving device. In order to improve the reception quality in the receiving device, it is necessary that signals having the same contents are broadcast from a plurality of broadcasting devices and the timings between the broadcasting devices are synchronized. In order to efficiently realize timing synchronization between broadcasting apparatuses, the broadcasting apparatus according to the present embodiment executes the following processing.

  In this embodiment, there are two types of broadcasting devices. One is a broadcast device that receives content data to be broadcast from an AV encoder, broadcasts an OFDM signal including the content data, and transmits the content data to another type of broadcast device (hereinafter referred to as “main broadcast device”). The other is a broadcasting device (hereinafter referred to as a “subordinate broadcasting device”) that receives content data from the main broadcasting device and broadcasts an OFDM signal including the content data, as described above. Here, in order to establish timing synchronization of the broadcasting device, the timing of the slave broadcasting device is synchronized with the timing of the main broadcasting device. The main broadcast device and the sub broadcast device generate a 1 pps pulse synchronized with the GPS timing based on the received signal at the GPS.

  The main broadcast device generates a plurality of MPEG2-TS packets (hereinafter sometimes simply referred to as packets) for storing content data and the like. Among these, TOT (Time Offset Table) packets are arranged at predetermined intervals. Specifically, TOT packets are arranged at intervals of 5 seconds, for example. Time information indicating the current date and time is inserted into the TOT packet. Therefore, in the case of being arranged at intervals of 5 seconds, the inserted time information is also a value every 5 seconds. Also, CRC (Cyclic Redundancy Check) data, which is data for error checking with respect to time information to be inserted, is inserted into the TOT packet. In the embodiment of the present invention, the main broadcast apparatus first stores information on the time difference between the timing of the TOT packet and the 1 pps pulse without storing the CRC data in a predetermined area in which the CRC data is to be stored. The master broadcast device transmits a plurality of packets including such TOT packets to the slave broadcast device. This transmission is performed by other than SFN. When the slave broadcast device receives a plurality of packets, the slave broadcast device extracts the TOT packet and executes timing synchronization with the main broadcast device based on the time difference information stored in the predetermined area. Thereafter, the main broadcast apparatus and the sub broadcast apparatus convert a plurality of packets into OFDM signals and broadcast. At that time, the time difference information is removed from the predetermined area of the TOT packet, and the normal CRC data is stored. This broadcast is made by SFN.

  FIG. 1 shows a configuration of an area one segment broadcasting system 100 according to an embodiment of the present invention. The area one segment broadcasting system 100 includes a main broadcasting device 10, a first GPS module 12, a HUB 14, a PC 16, a first wireless device 18, an AV encoder 20, a slave broadcasting device 30, a second GPS module 32, a second wireless device 34, and a receiving device. 40 is included. Further, an SFN area 50 is formed by the main broadcast device 10 and the sub broadcast device 30. Here, for clarity of explanation, one slave broadcast device 30 is shown, but a plurality of slave broadcast devices 30 may be included in the area one segment broadcast system 100.

  The first GPS module 12 acquires time information and a 1 pps pulse by receiving a signal from a GPS satellite. Since a known technique may be used for these acquisitions, description thereof is omitted here. The 1 pps pulse is a reference timing pulse having a period of 1 second. The first GPS module 12 outputs time information and a 1 pps pulse to the main broadcast device 10. The first GPS module 12 may acquire position information, but the description thereof is omitted here.

  The AV encoder 20 encodes the moving image audio data, multiplexes data broadcasting and SI (Service Information) / PSI (Program Specific Information) with the encoded moving image audio data, and generates a TS. Output to. The PC 16 controls the TS to be output from the AV encoder 20 via the HUB 14. The HUB 14 is connected to the main broadcast device 10, the PC 16, the AV encoder 20, and the first radio device 18, and relays TS, data, control signals, and the like. Communication via the HUB 14 is performed by, for example, IP (Internet Protocol).

  The main broadcast device 10 acquires time information and 1 pps pulse from the first GPS module 12. Also, the main broadcast device 10 acquires a TS from the AV encoder 20 via the HUB 14. The main broadcast device 10 obtains internally generated frame pulses. Here, the frame pulse has a period different from the period of the 1 pps pulse. The period of the frame pulse is, for example, 0.231336 seconds. The main broadcast device 10 generates a plurality of packets to be arranged between frame pulses. Here, some of the plurality of packets are TOT packets. TOT packets are arranged at intervals of 5 seconds, for example. The TOT packet includes information on the time difference between the TOT packet and the 1 pps pulse as well as the current time information as described above.

  The main broadcast device 10 transmits a plurality of packets to the first wireless device 18 via the HUB 14. The first wireless device 18 outputs a plurality of packets to the second wireless device 34. Communication between the first wireless device 18 and the second wireless device 34 is performed by, for example, a wireless LAN (Local Area Network), a wireless (Metropolitan Area Network) wireless WAN (Wide Area Network). The first radio apparatus 18 and the second radio apparatus 34 may communicate via a base station apparatus (not shown). Since the second radio apparatus 34 outputs a plurality of packets to the slave broadcast apparatus 30, the above processing corresponds to transmitting the generated plurality of packets to the slave broadcast apparatus 30.

  The main broadcast device 10 transforms some of the plurality of packets transmitted to the slave broadcast device 30. More specifically, the main broadcast apparatus 10 removes the time difference information from the predetermined area of the TOT packet and inserts CRC data into the predetermined area of the TOT packet instead of the time difference information. The main broadcast device 10 broadcasts the deformed packets to the SFN area 50 as OFDM signals. The main broadcast device 10 broadcasts after delaying the plurality of packets in order to match the transmission timing with the plurality of packets broadcast from the sub broadcast device 30.

  Since the second GPS module 32 executes the same process as the first GPS module 12, the description thereof is omitted here. The slave broadcast device 30 acquires time information and a 1 pps pulse from the second wireless device 34. In addition, the slave broadcast device 30 acquires a plurality of packets from the second wireless device 34. The sub broadcast device 30 transforms some of the plurality of packets received from the main broadcast device 10. More specifically, the slave broadcast device 30 removes time difference information from the TOT packet and inserts CRC data into the TOT packet instead of the time difference information. The slave broadcast device 30 broadcasts a plurality of modified packets to the SFN area 50 according to the time difference information. Note that the clocks of the main broadcast device 10 and the sub broadcast device 30 are based on 1 pps pulse, and the frame pulse is based on 1 pps pulse at a predetermined cycle selected by a TOT detection decoding unit described later among the 1 pps pulses. As a result, a plurality of packets broadcast from the main broadcast device 10 and a plurality of packets broadcast from the sub broadcast device 30 are received by the reception device 40.

  2A to 2D show timings in the area one segment broadcasting system 100. FIG. This modulation mode is MODE3, QPSK (2/3), and GI = 1/8. FIG. 2A shows a 1 pps pulse, which goes high at 1 second intervals. FIG. 2B shows a frame pulse, which goes high at intervals of 0.231336 seconds. FIG. 2C shows a plurality of TS packets arranged between frame pulses. As shown in the figure, 64 TS packets are arranged between adjacent frame pulses. From these relationships, the period in which the phases of the 1 pps pulse and the frame pulse overlap is 28917 seconds. FIG. 2D shows a 1 MHz clock. This is a clock of a period counter that represents the period of 1 pps pulse and frame pulse as an integer. In the ARIB STD-B31 standard, the phase difference of the frame pulse is expressed with respect to the phase of the 1 pps pulse with the resolution of 10 MHz clock. In this embodiment, the phase difference is expressed by using the 1 MHz clock.

  FIG. 3 shows the configuration of the main broadcast device 10. The main broadcast device 10 includes a LAN interface unit 200, a CPU 202, a TOT detection unit 204, a first TS number counting unit 206, a second acquisition unit 208, a clock count unit 210, a second generation unit 212, a first acquisition unit 214, a real time clock. Unit 216, clock generation unit 218, TOT detection decoding unit 220, second TS number counting unit 222, OFDM frame counting unit 224, write address control unit 226, read address control unit 228, buffer memory 230, transformation unit 232, broadcast unit 234 including. The CPU 202 includes a transmission unit 240 and a first generation unit 242.

  The first acquisition unit 214 acquires a 1 pps pulse by receiving a 1 pps pulse from the first GPS module 12. The second acquisition unit 208 acquires a frame pulse. For example, the second acquisition unit 208 generates a frame pulse based on the 1 pps pulse. Since a known technique may be used for generating the frame pulse, the description thereof is omitted here. The LAN interface unit 200 is connected to the HUB 14 and receives a TS from the HUB 14 as an IP packet. Here, the transmission rate of the TS matches the transmission rate of the main broadcast device 10.

  Based on the 1 pps pulse, the real-time clock unit 216 generates an interrupt signal at intervals of 5 seconds from the first GPS module 12 according to the time information. The real time clock unit 216 outputs an interrupt signal to the CPU 202 and the TOT detection decoding unit 220. The real-time clock unit 216 outputs a 1 pps pulse to the CPU 202, the second generation unit 212, and the clock count unit 210.

  The first generation unit 242 receives TS from the LAN interface unit 200 and also receives an interrupt signal from the real-time clock unit 216. The first generation unit 242 multiplexes TOT packets between a plurality of TS packets by an interrupt signal at intervals of 5 seconds. Since the priority of multiplexing is lower than that of the AV stream, the TOT packet is set at an interval of about 5 seconds. In addition, since the time of the TOT packet is based on the standard of the time when the receiving device 40 receives it, the preceding time is inserted when the TOT packet is multiplexed. Therefore, the TOT packet and the 1 pps phase are usually separated to some extent. As a result of such multiplexing, the first generation unit 242 generates a plurality of packets to be arranged between the frame pulses.

  The TOT detection unit 204 detects a TOT packet from the plurality of packets from the first generation unit 242, and outputs the detected timing to the first TS number counting unit 206. The first TS number counting unit 206 receives a detection notification from the TOT detection unit 204 and receives a plurality of packets from the first generation unit 242. Based on these, the first TS number counting unit 206 measures the number of packets between the TOT packet and the frame pulse. This corresponds to the TS number of the phase difference between the TOT packet and the frame pulse.

  The clock count unit 210 receives a 1 pps pulse from the real-time clock unit 216 and receives a frame pulse from the second acquisition unit 208. Based on these, the clock count unit 210 measures the number of clocks between the frame pulse and the 1 pps pulse. A 1 MHz clock is used for this measurement. The second generation unit 212 receives a plurality of packets from the first generation unit 242, the number of packets from the first TS number count unit 206, the number of clocks from the clock count unit 210, and the frame pulse from the second acquisition unit 208. The second generation unit 212 includes a combination of the number of packets and the number of clocks as time difference information in a TOT packet that is a part of a plurality of packets.

  FIGS. 4A to 4B show the format of the TOT packet generated in the main broadcast apparatus 10. FIG. 4A shows the format of a normal TOT packet. The TOT packet is composed of, for example, 188 bytes, and a TS header is arranged in the first 4 bytes. Time information is inserted into the payload, and CRC data for error checking for the time information is inserted into the 32-bit CRC data area.

  FIG. 4B shows the format of the TOT packet generated by the second generation unit 212. In this TOT packet, information on the time difference between the timing of the TOT packet and the 1 pps pulse is inserted in a 32-bit area (predetermined area) in which CRC data is to be inserted in the normal TOT packet. Specifically, the packet number information is inserted into an 11-bit area in a 32-bit area. The 11 bits are set because the maximum value of TS packets specified for TOT packets transmitted at intervals of about 5 seconds is the number of TSs 1384 (in some cases 1383) transmitted in 5 seconds. This is because the number of bits that can represent the value of 1384 is 11 bits. In addition, clock number information is inserted into an 18-bit area of the 32-bit area. The reason for 18 bits is that when the time difference from the frame pulse is designated by the number of clocks for the designated TS, the maximum number of clocks in the frame interval is 231336 clocks, and the number of bits that can represent 231336 is 18 bits. Because.

  The mode information is inserted into the 2-bit area of the 32-bit area. The mode information includes, for example, information indicating whether or not the packet number information and the clock number information are included in the 32-bit area. Is included. The initial value of the frame is inserted into the remaining 1-bit area of the 32-bit area. The initial value of the frame is 1-bit information of TMCC differential demodulation that is inverted every frame. Such a configuration is made possible by using a 1 MHz clock in this embodiment. For example, when the number of clocks is expressed using a 10 MHz clock, 22 bits are required as the clock number information, and the sum of the packet number information and the clock number information becomes larger than 32 bits. Clock number information cannot be included in the TOT packet instead of CRC data.

  The transmission unit 240 outputs the plurality of packets generated by the second generation unit 212 to the LAN interface unit 200. As a result, the plurality of packets are transmitted to the slave broadcasting device 30 via the HUB 14, the first wireless device 18, and the second wireless device 34. The buffer memory 230 stores the plurality of packets from the second generation unit 212 in order to delay the broadcast timing of the plurality of packets according to the transmission delay from the transmission unit 240 to the slave broadcasting device 30. This process will be described in detail. After the TOT detection decoding unit 220 detects the TOT packet, it selects the 1 pps pulse corresponding to the time information described in the TOT packet, that is, immediately after obtaining this time information. The write address control unit 226 sets the address of the buffer memory 230 and stores subsequent packets in order.

  The clock generation unit 218 generates a 1 MHz clock based on the 1 pps pulse. The OFDM frame count unit 224 reads the number of frame clocks from the TOT packet detected by the TOT detection decoding unit 220. The OFDM frame count unit 224 generates an OFDM frame pulse at a position corresponding to the number of clocks described in the TOT packet with reference to the phase of the selected 1 pps pulse. Second TS number counting section 222 counts the number of packets based on the phase of the selected 1 pps pulse and the OFDM frame pulse, and matches the phase of the frame period. The read address control unit 228 reads a plurality of packets from the buffer memory 230 according to the count numbers in the second TS number counting unit 222 and the OFDM frame counting unit 224.

  The deforming unit 232 deforms some of the plurality of packets from the buffer memory 230. Some of the packets to be modified are TOT packets. More specifically, the deforming unit 232 removes the time difference information from the predetermined area of the TOT packet and inserts CRC data into the predetermined area of the TOT packet instead of the time difference information. This corresponds to transforming FIG. 4B to FIG. 4A. The broadcast unit 234 broadcasts a plurality of packets obtained by modifying the TOT packet by the modification unit 232 as OFDM signals.

  The slave broadcast device 30 that has received the plurality of packets transmitted by the transmitter 240 also removes the time difference information from the predetermined area of the TOT packet and inserts CRC data into the predetermined area of the TOT packet instead of the time difference information. To do. The slave broadcast device 30 broadcasts a plurality of packets obtained by modifying the TOT packets as OFDM signals according to the time difference information.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it can be realized by a program loaded in the memory, but here it is realized by their cooperation. Draw functional blocks. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  FIG. 5 shows the configuration of the slave broadcast device 30. The slave broadcast device 30 includes a LAN interface unit 300, a CPU 302, an acquisition unit 314, a real-time clock unit 316, a clock generation unit 318, a TOT detection decoding unit 320, a TS number counting unit 322, an OFDM frame counting unit 324, and a write address control unit 326. , A read address control unit 328, a buffer memory 330, a deformation unit 332, and a broadcast unit 334. The CPU 302 includes a receiving unit 340.

  The receiving unit 340 receives a plurality of packets from the second wireless device 34 via the LAN interface unit 300. This corresponds to receiving a plurality of packets from the main broadcast device 10. As described above, the plurality of packets include the TOT packet, but the format is the same as that in FIG. The buffer memory 330 stores a plurality of packets received by the receiving unit 340. The acquisition unit 314, the real-time clock unit 316, the clock generation unit 318, the TOT detection decoding unit 320, the TS number counting unit 322, the OFDM frame counting unit 324, the write address control unit 326, and the read address control unit 328 are illustrated in FIG. Since it is the same as the acquisition unit 214, the real-time clock unit 216, the clock generation unit 218, the TOT detection decoding unit 220, the second TS number counting unit 222, the OFDM frame counting unit 224, the write address control unit 226, and the read address control unit 228, The description is omitted here.

  Similar to the deforming unit 232, the deforming unit 332 removes time difference information from a predetermined area of the TOT packet among a plurality of packets received by the receiving unit 340, and converts CRC data into the TOT packet information instead of the time difference information. Insert into a predetermined area. As a result, some of the plurality of packets are deformed. The broadcast unit 234 broadcasts a plurality of packets obtained by modifying the TOT packet by the modification unit 232 as OFDM signals. Here, the plurality of packets are broadcast according to the time difference information included in the TOT packet. Therefore, the broadcast timing of the slave broadcast device 30 is synchronized with the broadcast timing of the main broadcast device 10.

  The operation of the area one segment broadcasting system 100 configured as described above will be described. FIG. 6 is a sequence diagram showing a broadcasting procedure by the area one segment broadcasting system 100. The main broadcast device 10 inserts time difference information into a predetermined area of the TOT packet (S10). The main broadcast device 10 transmits a plurality of packets as OFDM signals (S12). The plurality of packets are transmitted from the main broadcast device 10 to the sub broadcast device 30 (S14). The main broadcast device 10 and the sub broadcast device 30 exclude the time difference information from the predetermined area of the TOT packet (S16, S18). The main broadcast device 10 and the sub broadcast device 30 insert CRC data in a predetermined area of the TOT packet (S20, S22). The main broadcast device 10 and the sub broadcast device 30 broadcast a plurality of packets as OFDM signals (S24, S26).

  According to the embodiment of the present invention, since the information on the time difference is included instead of the CRC data in the TOT packet, an instruction regarding synchronization can be transmitted efficiently. In addition, since an instruction regarding synchronization is efficiently transmitted, timing synchronization between broadcasting apparatuses can be efficiently realized. Since the time difference information is transmitted to the slave broadcast device, the timing can be synchronized with the slave broadcast device. Further, since the number of packets and the number of clocks are transmitted as time difference information, the amount of time difference information can be reduced. Also, since the time difference information is removed from the TOT packet and CRC data is inserted instead, the broadcast reception characteristics can be improved. In addition, since time difference information is received from the main broadcast device, timing synchronization with the main broadcast device can be performed efficiently.

  In addition, since the timing synchronization can be realized efficiently, it is possible to construct an SFN that is low cost and has no burden on the network line. In addition, when performing an area broadcast to construct an SFN, information on the time difference based on the clock that can efficiently express the relationship between the 1 pps pulse and the frame pulse selected by the time used as the reference for synchronization is included in the TOT packet, so it is invalid. Therefore, it is not necessary to use the TS remultiplexing format for transmitting the hierarchical layer TS, and the packet transmission efficiency can be improved. Also, when SFN is constructed and broadcast using GPS in area one segment broadcasting, there is no 188-byte RS part of the TS that matches the transmission TS that is transmitted by the broadcasting device for TS distributed over the network line It can be efficiently distributed in a format (a format that is not a broadcast TS). Further, since the information for SFN synchronization is transmitted by replacing the CRC part of the TOT packet, a TS with less waste can be distributed.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In the embodiment of the present invention, the area one segment broadcast system 100 executes one segment broadcast. However, the present invention is not limited to this. For example, these may execute a plurality of segment broadcasts. An example of the plurality of segment broadcasts is a full segment broadcast and a three segment broadcast. According to this modification, the present invention can be applied to various broadcasts.

  10 main broadcasting device, 30 slave broadcasting device, 100 area one segment broadcasting system, 200 LAN interface unit, 202 CPU, 204 TOT detection unit, 206 first TS number counting unit, 208 second acquisition unit, 210 clock counting unit, 212 second 2 generation unit, 214 first acquisition unit, 216 real time clock unit, 218 clock generation unit, 220 TOT detection decoding unit, 222 second TS number count unit, 224 OFDM frame count unit, 226 write address control unit, 228 read address control unit , 230 buffer memory, 232 transformation unit, 234 broadcast unit, 240 transmission unit, 242 first generation unit, 300 LAN interface unit, 302 CPU, 314 acquisition unit, 316 Real-time clock unit, 318 clock generation unit, 320 TOT detection decoding unit, 322 TS number count unit, 324 OFDM frame count unit, 326 write address control unit, 328 read address control unit, 330 buffer memory, 332 transformation unit, 334 broadcast unit 340 Receiver.

Claims (7)

An acquisition unit for acquiring a reference timing pulse having a predetermined period and a frame pulse having a period different from the period of the reference timing pulse;
A generating unit that generates a plurality of TS packets to be arranged between frame pulses acquired by the acquiring unit;
A transmission unit for transmitting a plurality of TS packets generated by the generation unit to another broadcasting device;
A deforming unit for deforming a TOT packet among a plurality of TS packets generated by the generating unit;
A broadcasting unit that broadcasts a plurality of TS packets including the modified TOT packet as an OFDM signal,
The generation unit includes information on a time difference between the TOT packet and a reference timing pulse in a predetermined area of the TOT packet.
The deforming unit removes time difference information from the predetermined area of the TOT packet and inserts error detection data into the predetermined area of the TOT packet instead of the time difference information.
The other broadcasting device that has received the plurality of TS packets transmitted by the transmission unit removes the time difference information from the predetermined area of the TOT packet, and uses error detection data in the predetermined area of the TOT packet instead of the time difference information. A broadcasting apparatus characterized by being inserted.   The generation unit includes a combination of the number of packets between a TOT packet and a frame pulse and the number of clocks between the frame pulse and a reference timing pulse as a time difference information in a predetermined region of the TOT packet. The broadcasting apparatus according to claim 1. A reference timing pulse having a predetermined period and a frame pulse having a period different from the period of the reference timing pulse are defined, and a plurality of TS packets arranged between the frame pulses are used as other OFDM signals as OFDM signals. A receiving unit for receiving from the broadcasting device;
A deforming unit for deforming a TOT packet among a plurality of TS packets received by the receiving unit;
A broadcasting unit that broadcasts a plurality of TS packets obtained by transforming the TOT packet as OFDM signals,
The predetermined area of the TOT packet among the plurality of TS packets received by the reception unit includes information on the time difference between the TOT packet and the reference timing pulse,
The deforming unit removes time difference information from the predetermined area of the TOT packet and inserts error detection data into the predetermined area of the TOT packet instead of the time difference information.
The broadcast unit broadcasts a plurality of TS packets as OFDM signals according to time difference information.   The information of the time difference included in the predetermined area of the TOT packet received by the receiving unit is based on the combination of the number of packets between the TOT packet and the frame pulse and the number of clocks between the frame pulse and the reference timing pulse. The broadcast apparatus according to claim 3, wherein the broadcast apparatus is displayed. Obtaining a reference timing pulse having a predetermined period and a frame pulse having a period different from the period of the reference timing pulse;
Generating a plurality of TS packets to be placed between acquired frame pulses;
Transmitting the generated plurality of TS packets to another broadcasting device;
Transforming a TOT packet among a plurality of generated TS packets;
Broadcasting a plurality of TS packets obtained by modifying the TOT packet as an OFDM signal,
The generating step includes information on a time difference between the TOT packet and the reference timing pulse in a predetermined region of the TOT packet among the plurality of TS packets.
The transforming step removes time difference information from a predetermined area of the TOT packet and inserts error detection data in the predetermined area of the TOT packet instead of the time difference information.
The other broadcasting apparatus that has received the plurality of TS packets transmitted by the transmitting step removes the time difference information from the predetermined area of the TOT packet, and uses error detection data instead of the time difference information in the predetermined area of the TOT packet. A transmission method characterized by being inserted into the network. A reference timing pulse having a predetermined period and a frame pulse having a period different from the period of the reference timing pulse are defined, and a plurality of TS packets arranged between the frame pulses are used as other OFDM signals as OFDM signals. Receiving from a broadcast device;
Transforming a TOT packet of a plurality of received TS packets;
Broadcasting a plurality of TS packets obtained by modifying the TOT packet as an OFDM signal,
The predetermined area of the TOT packet among the plurality of TS packets received by the receiving step includes information on a time difference between the TOT packet and the reference timing pulse,
The transforming step removes time difference information from a predetermined area of the TOT packet and inserts error detection data in the predetermined area of the TOT packet instead of the time difference information.
The transmitting step includes broadcasting a plurality of TS packets as OFDM signals according to time difference information. After acquiring a reference timing pulse having a predetermined period and a frame pulse having a period different from the period of the reference timing pulse, and generating a plurality of TS packets to be arranged between the acquired frame pulses, A master broadcasting device that transmits the generated plurality of TS packets to the slave broadcasting device, and transforms the TOT packet of the generated plurality of TS packets to broadcast as an OFDM signal;
A sub broadcast apparatus that transforms a TOT packet of a plurality of TS packets received from the main broadcast apparatus and broadcasts it as an OFDM signal,
The main broadcast device includes (1) information on a time difference between the TOT packet and a reference timing pulse in a predetermined area of the TOT packet among a plurality of TS packets for transmission, and (2) TOT for broadcast. While removing the time difference information from the predetermined area of the packet, inserting error detection data into the predetermined area of the TOT packet instead of the time difference information,
The slave broadcasting device (1) removes the time difference information from the predetermined area of the TOT packet, inserts error detection data into the predetermined area of the TOT packet instead of the time difference information, and (2) converts it into the time difference information. Accordingly, a broadcasting system that broadcasts a plurality of TS packets as OFDM signals.

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