JP2018078555A - Re-multiplexer, transmitter, receiver, chip, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the head position of a packet to be identified without adding a region indicating the head position to a packet for a low latency channel (Lch).SOLUTION: A re-multiplexer 20 includes: a packetizing unit 203 for capsulating package data for hierarchy and package data for low latency into respective variable-length first packets; a frame construction unit 206 for constructing frames by the layer obtained by making the first packet of the package data for hierarchy into a frame; symbol construction units 208 and 209 for constructing symbols from the first packet of the package data for low latency; and a transmission unit 212 for re-multiplexing the frames by the layer and the symbols and transmitting them as a second packet. The packetizing unit 203 stores a fixed value in the head of the first packets.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an OFDM transmission / reception system for transmitting a plurality of layers of data by OFDM (Orthogonal Frequency Division Multiplexing), and a remultiplexing device and a transmission device for remultiplexing the multiplexed layers of data , A receiving device, a chip, and a program.

  ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) is adopted as a current transmission system for digital terrestrial broadcasting in Japan (Non-Patent Document 1). In ISDB-T, the frequency band (about 6 MHz) of one channel is divided into 13 bands (segments). In order to provide services with different image quality and noise tolerance in the same channel, hierarchical transmission is performed in which different segments are allocated in the frequency band of one channel. In hierarchical transmission, the A layer, B layer,...

  Specifically, in the current ISDB-T, the frequency band of one channel is divided into 13 segments, the central one segment is used for A-layer transmission, and so-called one-segment broadcasting for mobile reception terminals is provided. Using 12 segments for B-layer transmission, it provides high-definition high-definition broadcasting for fixed receiving terminals.

  In recent years, the practical use of ultra-high-definition video called 8K Super Hi-Vision has been promoted, and the transmission system for next-generation terrestrial digital broadcasting corresponding to this has been studied.

  FIG. 20 shows main transmission parameters of provisional specifications for ISDB-T and next-generation digital terrestrial broadcasting. In the next-generation terrestrial digital broadcasting, for example, the signal bandwidth is increased from 5.57 MHz to 5.83 MHz, and the transmission capacity is increased by increasing the number of FFT points by 2 to 4 times. Further, it has been studied to increase the number of segments from 13 to 35, use the central 1 to 9 segments for A-layer transmission, and use the remaining segments for B-layer transmission. By controlling the number of segments, the bit rate of each layer can be finely adjusted, and flexibility can be improved.

  Furthermore, in next-generation terrestrial digital broadcasting, it is considered to transmit highly urgent data with a lower delay than the A layer and the B layer. In this specification, a channel transmitted with a low delay is referred to as “Lch”. Specifically, in the remultiplexing apparatus on the transmission side, the processing of the A layer and the B layer requires a delay of one frame or more because it constitutes a frame. On the other hand, Lch processing is performed at a symbol period, and a packet input to the remultiplexing apparatus is assigned to a symbol to be transmitted immediately and transmitted quickly, thereby realizing low-delay transmission.

“Transmission system for digital terrestrial television broadcasting” standard, ARIB STD-B31, Japan Radio Industry Association

  In the remultiplexing device, the input Lch packet is quickly transmitted to the transmitting device, and the transmission capacity is not reduced. Therefore, in addition to arithmetic processing such as LDPC encoding processing, the head position of the packet is set. It is desirable to omit the process of adding the designated area.

  An object of the present invention made in view of such circumstances is to provide a remultiplexing device, a transmitting device, and a remultiplexing device capable of specifying the leading position of the packet without adding a region indicating the leading position to the Lch packet. To provide a receiving device, a chip, and a program.

  In order to solve the above problems, a remultiplexing apparatus according to the present invention is a remultiplexing apparatus that remultiplexes a plurality of multiplexed layer package data and multiplexed low delay package data. A packetizing unit that encapsulates the package data for hierarchy and the low-latency package data into variable-length first packets, and a frame that constitutes a frame by hierarchy that frames the first packet of the package data for hierarchy A configuration unit, a symbol configuration unit that configures a symbol from the first packet of the low-latency package data, and a transmission unit that remultiplexes the frame by frame and the symbol and transmits the second packet as a second packet, The packetizing unit stores a fixed value at the head of the header area of the first packet.

  In order to solve the above problems, a transmission apparatus according to the present invention is transmitted from a remultiplexing apparatus that remultiplexes a plurality of multiplexed layer package data and multiplexed low-delay package data. A transmission device that receives the second packet and generates and transmits an OFDM signal, the input interface unit generating a hierarchical frame and a low delay frame from the second packet, the hierarchical frame and the low frame A modulation unit that arranges a delay frame at a predetermined position to form an OFDM frame and transmits an OFDM signal, and the second packet includes a variable-length first packet, A fixed value is stored at the head of the header area.

  In order to solve the above problem, a receiving apparatus according to the present invention is a receiving apparatus that receives an OFDM signal including a plurality of multiplexed hierarchical data and multiplexed low-delay data, and the OFDM A demodulation unit that demodulates a signal and generates the layer data and the low-delay data; and an output interface unit that specifies and outputs a variable-length packet from the layer data and the low-delay data, respectively. The output interface unit combines the low-delay data, searches for a fixed value, and identifies the fixed value as the head of the variable-length packet.

  In order to solve the above-described problem, the chip according to the present invention is mounted on a remultiplexing device that remultiplexes a plurality of multiplexed package data for a hierarchy and multiplexed low-latency package data. A packetizing unit that encapsulates the package data for the hierarchy and the package data for low delay into variable-length first packets, and a frame for each hierarchy in which the first packet of the package data for hierarchy is framed A frame configuration unit that configures a symbol, a symbol configuration unit that configures a symbol from the first packet of the low-latency package data, a transmission unit that remultiplexes the frame-by-layer frame and the symbol and transmits the second packet as a second packet, And the packetizer stores a fixed value at the beginning of the header area of the first packet. .

  In order to solve the above problem, a chip according to the present invention is transmitted from a remultiplexing device that remultiplexes a plurality of multiplexed layer package data and multiplexed low delay package data. A chip mounted on a transmitting device that receives a second packet and generates and transmits an OFDM signal, the input interface unit generating a layer-specific frame and a low-delay frame from the second packet; A modulation unit configured to arrange an OFDM frame by arranging a frame and the low-delay frame at a predetermined position and transmit an OFDM signal, and the second packet includes a variable-length first packet, A fixed value is stored at the head of the header area of the first packet.

  In order to solve the above problems, a chip according to the present invention is a chip mounted on a receiving apparatus that receives an OFDM signal including a plurality of multiplexed hierarchical data and multiplexed low delay data. A demodulator that demodulates the OFDM signal and generates the layer data and the low delay data, and an output interface unit that specifies and outputs a variable-length packet from the layer data and the low delay data, respectively. The output interface unit combines the low-delay data, searches for a fixed value, and identifies the fixed value as the head of the variable-length packet.

  In order to solve the above problems, a program according to the present invention causes a computer to function as the remultiplexing device.

  According to the present invention, it is possible to specify the start position of the packet without adding an area indicating the start position of the Lch packet to the low delay frame.

It is a figure which shows the structural example of the OFDM transmission / reception system which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the remultiplexing apparatus which concerns on one Embodiment of this invention. It is a figure which shows the structural example of a TLV (Type Length Value) packet. It is a figure which shows the structural example of a FEC (Forward Error Correction) block. It is a figure which shows the structural example of the flame | frame according to a hierarchy. It is a figure which shows the example of the division | segmentation of the flame | frame according to the hierarchy by the XMI (eXtensible Modulation Interface) packetization part of the remultiplexing apparatus which concerns on one Embodiment of this invention. It is a figure which shows the structural example of a XMI packet. It is a figure explaining the output of the XMI packet by the XMI packet transmission scheduler part of the remultiplexing apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating the other structural example of the staff XMI packet by the XMI packet transmission scheduler part of the remultiplexing apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of the value stored in the data unit classification of the XMI packet shown in FIG. It is a figure which shows the structural example of the transmitter which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the input interface part of the transmitter which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the modulation | alteration part of the transmitter which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the receiver which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the demodulation part of the receiver which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the output interface part of the receiver which concerns on one Embodiment of this invention. It is a flowchart which shows the operation example of the remultiplexing apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the operation example of the transmitter which concerns on one Embodiment of this invention. It is a flowchart which shows the operation example of the receiver which concerns on one Embodiment of this invention. It is a figure which shows the comparison of the main transmission parameters of the provisional specification of ISDB-T and the next generation digital terrestrial broadcasting.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In each figure, the same code | symbol has shown the same or equivalent component.

  FIG. 1 is a diagram illustrating a configuration example of an OFDM transmission / reception system 1 according to an embodiment of the present invention. The OFDM transmission / reception system 1 according to the present embodiment performs hierarchical transmission in which data of a plurality of layers and Lch data are transmitted through one channel. In the following, it is assumed that data of two layers of A layer data and B layer data is transmitted, but the number of layers is not limited to two layers.

  The OFDM transmission / reception system 1 illustrated in FIG. 1 includes a multiplexing device 10 (10a to 10c), a remultiplexing device 20, and a transmission device 30 on the transmission side. In addition, the receiving side includes a receiving device 40 and a demultiplexing device 50.

  The multiplexing device 10a is provided corresponding to the A layer, multiplexes the input video / audio signal for the A layer and the subtitle signal, and has a packet (MMT (MPEG Media Transport)) in a predetermined format (for example, MMT (MPEG Media Transport)). Packetized into MMTP (MMT Protocol) packets) and output as an A-layer package. More specifically, the transmission path between the multiplexer 10 and the remultiplexer 20 is an IP (Internet Protocol) transmission path, and the multiplexer 10 stores the MMTP packet in the IP packet and remultiplexes it. Output to the device 20. Therefore, hereinafter, a packet output from the multiplexing device 10 to the remultiplexing device 20 may be referred to as an MMTP / IP packet.

  Multiplexer 10b and multiplexer 10c are provided corresponding to the B layer and the Lch, respectively, and the corresponding B layer or Lch video / audio signal and caption signal are input. Each of the multiplexing apparatuses 10b and 10c, like the multiplexing apparatus 10a, multiplexes the input video / audio signal and subtitle signal, packetizes them into MMTP packets, and remultiplexes them as B layer packages and Lch packages. Output to the device 20.

  The remultiplexer 20 includes a plurality of layer package data (A layer package and B layer package) multiplexed by the multiplexers 10a and 10b, and a low delay package multiplexed by the multiplexer 10c. Data (Lch package) is remultiplexed and output to the transmitter 30. More specifically, the remultiplexing device 20 generates XMI packets from the MMTP packets output from the multiplexing devices 10 a, 10 b, and 10 c, remultiplexes them into one system, and outputs them to the transmission device 30. In the current ISDB-T, the packet output from the remultiplexing device to the transmission device is a TS (Transport Stream) packet.

  The transmission device 30 configures an OFDM frame using the XMI packet output from the remultiplexing device 20, and transmits the OFDM signal from the transmission antenna.

  The receiving device 40 receives the OFDM signal transmitted by the transmitting device 30, decodes the received OFDM signal into an MMTP / IP packet, and outputs the MMTP / IP packet to the demultiplexing device 50.

  The demultiplexer 50 separates the MMTP / IP packet output from the receiver 40 into a video / audio signal and a caption signal, and outputs the separated signal.

  Hereinafter, the configurations of the remultiplexing device 20, the transmission device 30, and the reception device 40 will be described. Note that the configurations of the multiplexing device 10 and the demultiplexing device 50 are well known to those skilled in the art and are not directly related to the present invention, and thus description thereof is omitted.

(Remultiplexer)
FIG. 2 is a diagram illustrating a configuration example of the remultiplexing apparatus 20. 2 includes packet filters 201a, 201b, and 201c, IP header compression units 202a, 202b, 202c, and 202d, TLV packetization units (packetization units) 203a, 203b, 203c, and 203d. FIFO (First in, First Out) buffers 204a, 204b, 204c, 204d, FEC block configuration units 205a, 205b, hierarchical frame configuration units (frame configuration units) 206a, 206b, and XMI packetization units 207a, 207b An L0 symbol configuration unit (symbol configuration unit) 208, an L1 symbol configuration unit (symbol configuration unit) 209, a synchronization control XMI packet configuration unit 210, a stuff XMI packet configuration unit 211, and an XMI packet transmission scheduler unit (transmission) Part) 212.

  The packet filter 201a, the IP header compression unit 202a, the TLV packetization unit 203a, the FIFO buffer 204a, the FEC block configuration unit 205a, the hierarchical frame configuration unit 206a, and the XMI packetization unit 207a are provided corresponding to the A layer. Yes.

  The packet filter 201a receives the A layer package from the multiplexing device 10a as an MMTP packet (MMTP / IP packet). The packet filter 201a transmits based on the source IP address, destination IP address, protocol type of the input MMTP / IP packet, the source port number of the UDP (User Datagram Protocol) header, the destination port number, and the like. The packet is selected (packet filtering), and the selected MMTP / IP packet is output to the IP header compression unit 202a.

  The IP header compression unit 202a compresses the IP header of the MMTP / IP packet output from the packet filter 201a as necessary, and outputs the result to the TLV packetization unit 203a.

  The TLV packetization unit 203a encapsulates the MMTP / IP packet output from the IP header compression unit 202a into a variable-length TLV packet (first packet) to generate a TLV packet.

  FIG. 3 is a diagram illustrating a configuration example of a TLV packet. In the following, the numbers given to each field (area) indicate an example of the number of bits in each field. As shown in FIG. 3, the TLV packet includes a reserved area, a packet type area, a data length area, and a data area. The reserved area, the packet type area, and the data length area are header areas.

  A fixed value (for example, 0x7F) is stored in the reserved area at the head of the header area. In the present invention, the head position of the TLV packet of the Lch data is specified using a fixed value stored in the reserved area as will be described later.

  The packet type area indicates the packet type (for example, IPv4, IPv6, etc.) of the TLV packet.

  The data length area indicates the size of data stored in the data area.

  In the data area, the IP packet output from the IP header compression unit 202a or the MMTP / IP packet compressed with the IP header is stored.

  Referring to FIG. 2 again, the TLV packetization unit 203a outputs the generated TLV packet to the FIFO buffer 204a.

  The FIFO buffer 204a stores the TLV packet output from the TLV packetization unit 203a, and outputs the stored TLV packet to the FEC block configuration unit 205a in the order of storage.

  The FEC block configuration unit 205a configures an FEC block at a constant cycle from the TLV packet output from the FIFO buffer 204a.

  FIG. 4 is a diagram illustrating a configuration example of the FEC block. As shown in FIG. 4, the FEC block includes an FEC block header area, a main signal area, a BCH parity area, a stuff bit area, and an LDPC parity area. Although FIG. 4 shows one main signal area and one BCH parity area, there are cases where each is divided into a plurality.

  The main signal area stores the TLV packet output from the FIFO buffer 204a.

  The FEC block header area (start TLV indication area) indicates the start position of the first TLV packet stored in the main signal area, specifically, the position of the start byte of the first TLV packet stored in the main signal area. Information indicating the number of bytes from the head of the main signal area is stored.

  Bit “1” is stored in all of the BCH parity area, the stuff bit area, and the LDPC parity area.

  Note that three types of FEC block sizes are set according to the code length (Short, Middle, Long) of LDPC encoding performed by the transmission apparatus 30. The sizes of the main signal area, the BCH parity area, the stuff bit area, and the LDPC parity area are determined according to the coding rate.

  The FEC block configuration unit 205a concatenates the TLV packets output from the FIFO buffer 204a in the output order and stores them in the main signal area, and sets the value of the head TLV instruction area for each FEC block. Note that when the TLV packet to be stored in the main signal area does not exist in the FIFO buffer 204a, the FEC block configuration unit 205a stores the null type TLV packet in the main signal area.

  Referring to FIG. 2 again, the FEC block configuration unit 205a outputs the configured FEC block to the hierarchical frame configuration unit 206a.

  The frame-by-layer configuration unit 206a forms a frame by layer by framing the FEC block output from the FEC block configuration unit 205a.

  FIG. 5 is a diagram illustrating a configuration example of a frame by layer. As shown in FIG. 5, the hierarchical frame includes a frame header area and an FEC block area.

  In the FEC block area, a concatenation of FEC blocks output from the FEC block configuration unit 205a and a fragment of the FEC block are stored. Note that the size of the layer-specific frame is determined according to the modulation scheme, FFT size, guard interval ratio, pilot signal ratio, and number of segments.

  The frame header area includes an FEC block pointer having a predetermined number of bits (19 bits in FIG. 5), and bit “1” is stored in the remaining area. Since the FEC block area can be stored across FEC blocks, the FEC block pointer indicates the start bit of the first FEC block including the start of the FEC block stored in the hierarchical frame from the start position of the FEC block area. Indicates the position in bits.

  The hierarchical frame configuration unit 206a concatenates the FEC blocks output from the FEC block configuration unit 205a in the output order, stores the FEC blocks in the FEC block area, and calculates the FEC block pointer from the position of the FEC block stored in the FEC block area. Stored in the frame header.

  Referring again to FIG. 2, the layer-specific frame configuration unit 206a outputs the configured layer-specific frame to the XMI packetization unit 207a.

  The packet filter 201b, the IP header compression unit 202b, the TLV packetization unit 203b, the FIFO buffer 204b, the FEC block configuration unit 205b, the hierarchical frame configuration unit 206b, and the XMI packetization unit 207b are provided corresponding to the B layer. Yes. Since the configuration corresponding to the A layer and the configuration corresponding to the B layer are the same, the description of the configuration corresponding to the B layer is omitted.

  The packet filter 201c, the IP header compression units 202c and 202d, the TLV packetization units 203c and 203d, the FIFO buffers 204c and 204d, the L0 symbol configuration unit 208, and the L1 symbol configuration unit 209 are provided corresponding to the Lch.

  The packet filter 201c receives an Lch MMTP / IP packet from the multiplexer 10c. The packet filter 201c selects a packet to be transmitted based on a source IP address, a destination IP address, a protocol type, a source port number in a UDP header, a destination port number, etc. (packet filtering) The selected MMTP / IP packet is output to the IP header compression unit 202c or the IP header compression unit 202d.

  The IP header compression unit 202c compresses the IP header of the MMTP / IP packet output from the packet filter 201c as necessary, and outputs the result to the TLV packetization unit 203c. The IP header compression unit 202d compresses the IP header of the MMTP / IP packet output from the packet filter 201c as necessary, and outputs the result to the TLV packetization unit 203d.

  The TLV packetization unit 203c encapsulates the MMTP / IP packet output from the IP header compression unit 202c into a TLV packet, generates a TLV packet, and outputs the TLV packet to the FIFO buffer 204c. The TLV packetization unit 203d encapsulates the MMTP / IP packet output from the IP header compression unit 202d into a TLV packet, generates a TLV packet, and outputs the TLV packet to the FIFO buffer 204d.

  The FIFO buffer 204c stores the TLV packet output from the TLV packetization unit 203c, and outputs the stored TLV packets to the L0 symbol configuration unit 208 in the order of storage. The FIFO buffer 204d stores the TLV packet output from the TLV packetization unit 203d, and outputs the stored TLV packets to the L1 symbol configuration unit 209 in the storage order.

  For example, the L0 symbol is transmitted in 9 segments for partial reception, and the L1 symbol is transmitted in the other 24 or 26 segments. Therefore, packet filtering by the packet filter 201c is also performed according to such allocation.

  When the number of segments is N, the number of bits of L0 and L1 symbols per OFDM frame is 4 × N bits for 8K FFT, 8 × N bits for 16K FFT, and 16 × N bits for 32K FFT. That is, when 9 segments are allocated to the L0 symbol and 24 segments are allocated to the L1 symbol, in the case of 16K FFT, the L0 symbol per OFDM frame is 72 bits and the L1 symbol is 192 bits. The L0 symbol configuration unit 208 allocates each byte of the TLV packet output from the FIFO buffer 204c to the L0 symbol having such a size in MSB (Most Significant Bit) first to form an L0 symbol, and the XMI packet transmission scheduler unit 212 Output to. Similarly, the L1 symbol configuration unit 209 allocates each byte of the TLV packet output from the FIFO buffer 204d to the L1 symbol having such a size MSB first to configure the L1 symbol, and sends it to the XMI packet transmission scheduler unit 212. Output. Here, the MSB first means that the most significant bit of each byte constituting the TLV packet is a bit string starting from the top.

  The XMI packetization unit 207a configures an XMI packet from the layer-by-layer frame output from the layer-by-layer frame configuration unit 206a.

  FIG. 6 is a diagram illustrating an example of division of frames by layer by the XMI packetization unit 207a. As shown in FIG. 6, the XMI packetizing unit 207a divides the hierarchical frame into a predetermined size (10448 bits in FIG. 6) to form a data unit.

  FIG. 7 is a diagram illustrating a configuration example of the XMI packet output from the remultiplexing apparatus 20. The XMI packet has a header area and a data unit area. As shown in FIG. 7, the header area of the XMI packet has an IPv4 header, a UDP header, a header of an MMTP packet (MMTP header), and an XMI header. Synchronization control information or data units are stored in the data unit area of the XMI packet. When the number of bits is less than the predetermined number, stuff bits are added. For the XMI packet in which the data unit is stored in the data unit area, a channel information area for storing the L0 symbol and the L1 symbol is provided in the data unit area, but the description is omitted in FIG.

  The IPv4 header has the same configuration as the IPv4 header part defined in Part 3 of ARIB STD-B32. The UDP header has the same configuration as the UDP header part defined in Part 3 of ARIB STD-B32. The MMTP packet has the same configuration as the MMTP packet defined in ARIB STD-B60, except that the XMI packet is stored in the payload area.

  The payload area (MMTP payload) of the MMTP packet stores the XMI header and below. The MMTP header stores information indicating the data type of data stored in the MMTP payload, information for identifying the type of data stored in the MMTP payload, and the like.

  As shown in FIG. 7, the XMI header includes an L0 head symbol flag, an L0 symbol start flag, an L1 head symbol flag, an L1 symbol start flag, a frame number, a data unit type, a sequence number, and CRC_32. Data unit length.

  The L0 head symbol flag indicates whether or not the L0 symbol stored in this XMI packet is the first symbol of the OFDM frame. The L1 head symbol flag indicates that the L1 symbol stored in this XMI packet is the first symbol of the OFDM frame. Whether or not.

  The L0 symbol start flag indicates whether or not the L0 symbol of this XMI packet is stored together with information indicating the size thereof, and the L1 symbol start flag is information indicating the size of the L1 symbol of this XMI packet. Whether it is stored together.

  The frame number indicates the number of the frame to which the data unit stored in the XMI packet belongs.

  The data unit type indicates whether the data stored in the data unit area of the XMI packet is synchronization control information, whether it is a data unit, or whether it is a stuff bit. The value of the data unit type is, for example, “0” when the data unit area stored in the XMI packet is synchronization control information. Further, for example, when hierarchical transmission from the A layer to the C layer is performed, the value of the data unit type is stored in the data unit area of the XMI packet in the data unit of the hierarchical layer of the A layer. Is “1”, “2” if the data unit is a data unit of a B-level hierarchical frame, and “3” if the data unit is a data unit of a C-level hierarchical frame. The value of the data unit type is “4” or “15” when the data unit area of the XMI packet is stuff bits. “5” to “14” are reserved areas.

  The sequence number indicates the order of XMI packets in the OFDM frame.

  In CRC_32, CRC (Cyclic Redundancy Check) is written in accordance with ITU-T recommendation H222.0. The data unit length indicates the size of the data unit in the XMI packet.

  The XMI packetizing unit 207a stores the data unit in the data unit area of the XMI packet. As shown in FIG. 6, the last data unit may be smaller than a predetermined size (in FIG. 6, less than 10448 bits). In this case, the XMI packetizing unit 207a adds a predetermined bit (stuff bit) to a data unit that does not satisfy the predetermined size to obtain a predetermined size, and stores it in the data unit area.

  The synchronization control XMI packet configuration unit 210 is an XMI that stores synchronization control information indicating transmission control information such as transmission parameters for the transmission apparatus 30 to configure an OFDM frame, transmission timing of the OFDM frame, and TMCC information in the data unit area. A packet (synchronization control XMI packet) is configured and output to the XMI packet transmission scheduler unit 212. The synchronization control XMI packet configuration unit 210 adds stuff bits to the synchronization control information to a predetermined size and stores it in the data unit area when the synchronization control information does not satisfy the predetermined size for dividing the frame by layer. To do.

  The stuff XMI packet configuration unit 211 configures an XMI packet (stuff XMI packet) in which only stuff bits having the same size as the data unit are stored in the data unit area, and outputs the XMI packet to the XMI packet transmission scheduler unit 212. The stuff XMI packet is used to keep the number of XMI packets output per second from the remultiplexing device 20 even when the modulation method and the coding rate are different.

  By indicating the size of the data unit in the XMI packet by the data unit length of the XMI header, the size of the data unit can be specified even when stuff bits are added.

  The synchronization control XMI packet configuration unit 210 sets a value corresponding to the synchronization control XMI packet, for example, “0” in the data unit type of the XMI header when configuring the XMI packet. When configuring the XMI packet, the XMI packetizing unit 207a sets a value corresponding to the XMI packet in the A layer, for example, “1” in the data unit type of the XMI header. When configuring the XMI packet, the XMI packetizing unit 207b sets a value corresponding to the BMI layer XMI packet, for example, ‘2’, in the data unit type of the XMI header. The stuff XMI packet configuration unit 211 sets a value corresponding to the stuff XMI packet, for example, “15” in the data unit type of the XMI header when the XMI packet is configured. By doing so, it is possible to specify the type of object to be stored in the XMI packet.

  The XMI packet transmission scheduler unit 212 includes an A layer XMI packet output from the XMI packetization unit 207a, a B layer XMI packet output from the XMI packetization unit 207b, an L0 symbol and an L1 symbol output from the L0 symbol configuration unit 208 The L1 symbol output from the configuration unit 209, the synchronization control XMI packet output from the synchronization control XMI packet configuration unit 210, and the stuff XMI packet output from the stuff XMI packet configuration unit 211 are re-multiplexed to generate an XMI packet (second Packet) to the transmitting device 30.

  FIG. 8 is a diagram for explaining the output of the XMI packet by the XMI packet transmission scheduler unit 212. The XMI packet transmission scheduler unit 212 outputs one synchronization control XMI packet at the beginning of the OFDM frame. Subsequently, the XMI packet transmission scheduler unit 212 outputs XMI packets (A layer XMI packet and B layer XMI packet) of each layer. When all the XMI packets of each layer are output, the XMI packet transmission scheduler unit 212 outputs the stuff XMI packets so that the number of XMI packets constituting the OFDM frame becomes a constant number. Note that the XMI packet transmission scheduler unit 212 may output at least one stuff XMI packet, for example, to indicate the end of the output of the XMI packet in the OFDM frame.

  Here, as shown in FIG. 8, in order to store the L0 symbol and the L1 symbol in the data unit area of the A layer XMI packet and the B layer XMI packet (XMI packet that transmits the data unit), a predetermined number of bytes. (For example, 4 bytes) of channel information areas (L0 symbol storage area and L1 symbol storage area) are provided.

  When the L0 symbol is output from the L0 symbol configuration unit 208, the XMI packet transmission scheduler unit 212 promptly (with low delay) inputs the L0 symbol into the L0 symbol storage area of the XMI packet that transmits the data unit. Assign and output to the transmitter 30. In addition, when the L1 symbol is output from the L1 symbol configuration unit 209, the XMI packet transmission scheduler unit 212 promptly transmits the input L1 symbol (low delay) to the L1 symbol storage area of the XMI packet that transmits the data unit. And output to the transmitter 30. In this way, Lch data can be output to the transmission device 30 with low delay. When there is no Lch TLV packet, the XMI packet transmission scheduler unit 212 stores null in the channel information area.

  As described above, for example, in 8K FFT, the number of bits of the L0 symbol and the L1 symbol is 4 × N bits. Here, when N is an odd number, the number of bits is not a multiple of 8 (byte alignment cannot be obtained). For this reason, one byte cannot be configured and cannot be stored in the XMI packet. In this case, byte alignment is performed by combining consecutive LCH symbols (L0 symbol, L1 symbol) or adding a null to the end of the LCH symbol, and a channel information area (L0 symbol storage area and L1 symbol storage area). The null added for byte alignment is removed by the modulation unit 32 described later.

  FIG. 8 shows an example in which the stuff XMI packet is not provided with channel information areas (L0 symbol storage area and L1 symbol storage area) for storing L0 symbols and L1 symbols. In this case, during the period in which the stuff XMI packet is output, the L0 symbol and the L1 symbol cannot be output to the transmission device 13, which is a cause of impairing the feature of low LCH delay.

  Therefore, as shown in FIG. 9, the stuff XMI packet may also be provided with an L0 symbol storage area and an L1 symbol storage area for storing the L0 symbol and the L1 symbol. In this case, the stuff XMI packet configuration unit 211 has a stuff XMI packet (third packet) that includes an L0 symbol storage area and an L1 symbol storage area, and a stuff XMI packet storage area that does not include an L0 symbol storage area and an L1 symbol storage area. An XMI packet (fourth packet) is generated and output to the XMI packet transmission scheduler unit 212. Hereinafter, the stuff XMI packet including the L0 symbol storage area and the L1 symbol storage area is referred to as L0 / L1 symbol data. In the L0 / L1 symbol data, dummy data for stuffing is subsequently stored in the L0 symbol storage area and the L1 symbol storage area to form a fixed-length XMI packet.

  When the L0 symbol is input from the L0 symbol configuration unit 208, the XMI packet transmission scheduler unit 212 promptly sends the input L0 symbol to the L0 symbol storage area of the XMI packet or L0 / L1 symbol data transmitting the data unit. (With low delay) and output to the transmitter 13. Further, when the L1 symbol is input from the L1 symbol configuration unit 209, the XMI packet transmission scheduler unit 212 receives the input L1 symbol in the L1 symbol storage area of the XMI packet or L0 / L1 symbol data that transmits the data unit. Are assigned promptly (with low delay) and output to the transmitter 13. In this way, LCH data can be output to the transmission device 13 with low delay even during the stuff XMI packet transmission period. FIG. 9 shows an example in which one stuff XMI packet not including the L0 symbol storage area and the L1 symbol storage area is output. However, the present invention is not limited to this, and the L0 symbol storage area is not limited thereto. In addition, two or more stuff XMI packets that do not include the L1 symbol storage area may be output or may not be output.

  When a stuff XMI packet (L0 / L1 symbol data) having an L0 symbol storage area and an L1 symbol storage area is provided, in L0 / L1 symbol data, the value of the data unit type in the XMI packet is shown in FIG. As shown, “4” is set, and “5” to “14” are reserved areas. That is, the value of the data unit type in the XMI packet indicates that the XMI packet is stored in the XMI packet (first packet), the synchronization control XMI packet (second packet), the L0 symbol storage area, and the L1 symbol in each layer. The stuff XMI packet (third packet) having the area for use, the stuff XMI packet (fourth packet) not having the L0 symbol storage area, and the L1 symbol storage area.

(Transmitter)
Next, a configuration example of the transmission device 30 will be described with reference to FIG. A transmission device 30 illustrated in FIG. 11 includes an input interface unit 31 and a modulation unit 32.

  The input interface unit 31 receives the XMI packet output from the remultiplexing device 20 and concatenates the layer data and the Lch data (low delay data), respectively, to connect the A layer frame, the B layer frame, and the Lch frame (low channel). (Delay frame) is generated and output to the modulation unit 32. As described above, the XMI packet includes a variable-length TLV packet, and a fixed value is stored at the head of the header area of the TLV packet.

  The modulation unit 32 configures an OFDM frame from the frame output from the input interface unit 31 based on the transmission parameter included in the synchronization control information, and transmits the OFDM signal from the transmission antenna 33.

  FIG. 12 is a diagram illustrating a configuration example of the input interface unit 31. The input interface unit 31 shown in FIG. 12 includes an XMI packet receiving unit 311, an A layer frame generating unit 312a, a B layer frame generating unit 312b, an Lch frame generating unit 312c, and a control information / TMCC information generating unit 313. Prepare.

  The XMI packet receiving unit 311 receives the XMI packet output from the remultiplexing apparatus 20, outputs the A layer XMI packet to the A layer frame generation unit 312a, and outputs the B layer XMI packet to the B layer frame generation unit 312b. Output to. The XMI packet receiving unit 311 also outputs the A layer XMI packet and the B layer XMI packet to the Lch frame generation unit 312c. Further, the XMI packet receiving unit 311 outputs the synchronization control XMI packet including the synchronization control information to the control information / TMCC information generating unit 313.

  As described above, in the XMI header of the XMI packet, whether the data unit area of the XMI packet is the synchronization control information, whether it is the data unit of the A layer or the B layer, the staff A data unit type indicating whether it is a bit or not is included. The XMI packet receiving unit 311 can identify the type of each XMI packet by referring to the value of the data unit type and output it to an appropriate output destination.

  The A layer frame generation unit 312 a concatenates the data units included in the A layer XMI packet output from the XMI packet reception unit 311, generates an A layer frame, and outputs the frame to the modulation unit 32. The B layer frame generation unit 312 b concatenates the data units included in the B layer XMI packet output from the XMI packet reception unit 311, generates a B layer frame, and outputs the frame to the modulation unit 32.

  The Lch frame generation unit 312 c concatenates the L0 symbol and the L1 symbol included in the XMI packet output from the XMI packet reception unit 311, generates an Lch frame, and outputs the Lch frame to the modulation unit 32.

  The control information / TMCC information generation unit 313 indicates control information indicating various information for configuring an OFDM frame, and transmission parameters from the synchronization control information included in the synchronization control XMI packet output from the XMI packet reception unit 311. TMCC information is generated and output to the modulation unit 32.

  FIG. 13 is a diagram illustrating a configuration example of the modulation unit 32. 13 includes an A layer processing unit 321a, a B layer processing unit 321b, an Lch processing unit 321c, a TMCC signal generation unit 322, a layer synthesis unit 323, a framing unit 324, and an IFFT ( An Inversed Fast Fourier Transform) unit 325 and an output unit 326 are provided.

  The A layer processing unit 321a performs frame header separation, FEC block conversion, energy spreading, BCH coding, LDPC coding, bit interleaving, frame header coding, frame processing on the A layer frame input from the input interface unit 31. Predetermined processing such as header insertion and mapping is performed to generate a carrier symbol, which is output to the layer synthesis unit 323.

  The B layer processing unit 321 b performs predetermined processing on the B layer frame input from the input interface unit 31 in the same manner as the A layer processing unit 321 a to generate a carrier symbol, and outputs the carrier symbol to the layer combining unit 323.

  The Lch processing unit 321c performs predetermined processing such as error correction coding, differential reference addition, and DBPSK (Differential Binary Phase Shift Keying) modulation on the Lch frame input from the input interface unit 31. The carrier symbol is output to framing section 324.

  The TMCC signal generation unit 322 generates a TMCC signal based on the control information / TMCC information input from the input interface unit 31 and outputs the TMCC signal to the framing unit 324.

  The layer combining unit 323 combines the layer A carrier symbol output from the layer A processing unit 321a and the layer B carrier symbol output from the layer B processing unit 321b, and transmits the data segment in one OFDM frame. Is generated and output to the framing unit 324.

  The framing unit 324 outputs the layer A and B layer carrier symbols output from the layer combining unit 323, the L channel carrier symbols output from the Lch processing unit 321c, and the TMCC signal generation unit 322. The TMCC signal and a pilot signal (not shown) are arranged at a predetermined carrier and symbol position, thereby forming an OFDM frame and outputting it to the IFFT unit 325.

  IFFT section 325 performs an inverse Fourier transform process such as IFFT on the OFDM frame output from framing section 324, converts the frequency domain signal to a time domain signal, and outputs the result to output section 326.

  The output unit 326 performs processing such as guard interval addition, quadrature modulation, digital-analog conversion, and power amplification in order to transmit the signal output from the IFFT unit 325.

(Receiver)
Next, a configuration example of the receiving device will be described with reference to FIG. 14 includes a demodulator 41 and an output interface unit 42.

  The demodulation unit 41 receives the OFDM signal transmitted from the transmission device 30 via the reception antenna 43 and demodulates it. The received OFDM signal includes A layer, B layer, and Lch carrier symbols.

  The demodulator 41 performs processing for returning the processing performed by the transmission device 30 to the A layer, B layer, and Lch carrier symbols after the Fourier transform processing. For example, when the interleaving process and the energy spreading process are performed only on the data of the A layer and the B layer in the transmission device 30, the demodulator 41 performs the processing on the data of the A layer and the B layer. Deinterleaving processing and energy despreading processing are performed, and these processing is not performed on Lch data. Further, when different error correction coding processes are performed in the A layer, the B layer, and the Lch, an error correction decoding process corresponding to each is performed.

  FIG. 15 is a diagram illustrating a configuration example of the demodulation unit 41. 15 includes an input unit 411, an FFT (Fast Fourier Transform) unit 412, an equalization unit 413, a layer division unit 414, an A layer FEC block conversion unit 415a, and a B layer FEC block conversion. Unit 415b, layer A decoding unit 416a, layer B decoding unit 416b, and Lch demodulation unit 417.

  The input unit 411 receives the OFDM signal transmitted from the transmission device 30 via the reception antenna 43, performs processes such as analog-digital conversion, quadrature modulation, and guard interval removal, and outputs the result to the FFT unit 412.

  The FFT unit 412 performs a Fourier transform process such as FFT on the signal output from the input unit 411, converts the signal in the time domain into a signal in the frequency domain, and outputs the signal to the equalization unit 413 and the Lch demodulation unit 417. .

  The equalization unit 413 extracts a pilot signal from the signal output from the FFT unit 412 and estimates the propagation path characteristic. Then, an equalization coefficient is calculated, and equalization processing is performed on the signal output from the FFT unit 412. For example, a zero forcing standard is used for equalization.

  The layer division unit 414 divides the signal output from the equalization unit 413 into a layer A carrier symbol and a layer B carrier symbol, and outputs the layer A carrier symbol to the layer A FEC block conversion unit 415a. The layer carrier symbol is output to the B layer FEC block conversion unit 415b.

  The A layer FEC block conversion unit 415a calculates the LLR (log likelihood ratio) of the carrier symbol of the A layer output from the layer dividing unit 414, generates an LDPC block by dividing the code into each LDPC code length, and generates the A layer It outputs to the decoding part 416a. The B layer FEC block converting unit 415b calculates the LLR of the B layer carrier symbol output from the layer dividing unit 414, generates an LDPC block for each LDPC code length, and outputs the LDPC block to the B layer decoding unit 416b. .

  The A layer decoding unit 416a performs LDPC decoding using the LLR output from the A layer FEC block conversion unit 415a, performs BCH decoding, and outputs the decoded A layer bit data to the output interface unit 42. The B layer decoding unit 416b performs LDPC decoding using the LLR output from the B layer FEC block conversion unit 415b, performs BCH decoding, and outputs the decoded B layer bit data to the output interface unit 42.

  The Lch demodulator 417 extracts an Lch carrier from the signal output from the FFT unit 412, performs DBPSK demodulation, and demodulates the Lch signal. Then, error correction of the Lch signal is performed, and the decoded Lch bit data is output to the output interface unit 42.

  The output interface unit 42 specifies and outputs each variable-length TLV packet from the A layer bit data, the B layer bit data, and the Lch bit data.

  FIG. 16 is a diagram illustrating a configuration example of the output interface unit 42. The output interface unit 42 illustrated in FIG. 16 includes bit byte conversion units 421a, 421b, and 421c, TLV (Types Length Value) packet separation units 422a, 422b, and 422c, IP header decompression units 423a, 423b, and 423c, and Eth− IF (Ethernet (registered trademark) interface) 424a and 424b.

  The bit byte conversion unit 421a converts the A layer bit data input from the demodulation unit 41 into byte data, and outputs the A layer byte data to the TLV packet separation unit 422a. The bit byte conversion unit 421b converts the B layer bit data input from the demodulation unit 41 into byte data, and outputs the B layer byte data to the TLV packet separation unit 422b. The bit byte conversion unit 421c converts the Lch bit data input from the demodulation unit 41 into byte data, and outputs the Lch byte data to the TLV packet separation unit 422c.

  The TLV packet separation unit 422a is the main signal region of the FEC block in which the syndrome becomes zero as a result of error correction decoding by the demodulation unit 41 for the A layer byte data output from the bit byte conversion unit 421a (see FIG. 4). Join. Then, an individual TLV packet is identified from the FEC block header area (first TLV indication area) of the FEC block and the data length area (see FIG. 3) of the TLV packet, and is output as an IPv4 packet. However, when a part of the TLV packet is transmitted in the FEC block in which the syndrome is not zero, the TLV packet is discarded. A null type TLV packet is also discarded. The TLV packet separation unit 422b performs the same processing on the B layer byte data output from the bit byte conversion unit 421b.

  For Lch data, no FEC block is generated in the transmission device 30 in order to shorten the delay time and not to reduce the transmission capacity. Therefore, there is no area that indicates the head position of the TLV packet. Therefore, in the present invention, the start position of the Lch data packet is specified using a fixed value stored in the start reserved area (see FIG. 3) of the header area of the TLV packet.

  Specifically, the TLV packet separation unit 422c combines the Lch byte data output from the bit byte conversion unit 421c and uses the combined data as data on the stream. From this, a fixed value (reserved area) that is the first byte of the TLV packet is searched. In this embodiment, the value of the reserved area is a fixed value of 0x7F. 1 byte (packet type area) immediately after the reserved area is skipped, 2 bytes (data length area) immediately after that are read, and it is confirmed that 1 byte offset by this size is 0x7F. By repeating this operation one or more times (for example, three times), the head of the TLV packet is identified, and the TLV packet is identified from the data on the stream as a structure having a packet type area, a data length area, and a data area. ,Output.

  The TLV packet transmitted in the A layer, the TLV packet transmitted in the B layer, and the TLV packet transmitted in the Lch are output from the same Ethernet port (Eth-IF 424a), but these are the UDP destination port numbers. Distinguish by. When outputting from the Ethernet port, the IPv4 packet interval is adjusted and output so that the TLV packet transmitted in the OFDM frame is output in the OFDM frame time.

  There are five types of TLV packets: IPv4 packets, IPv6 packets, header-compressed IP packets, transmission control signal packets, and null packets. When the TLV packet is an IPv4 packet or an IPv6 packet, the IP header decompression unit 423a extracts each IP packet from the data area of the TLV packet and outputs it to the Eth-IF 424b. If the TLV packet is an IP packet with header compression, the compressed IP header is restored, the IP packet at the time of transmission is restored, and the packet is output to the Eth-IF 424b as an IPv4 packet or an IPv6 packet. If the TLV packet is a transmission control signal packet or a null packet, it is discarded. When outputting these IP packets, the interval between the IP packets is adjusted and output so that the IP packet transmitted in the OFDM frame is output in the OFDM frame time. The IP header decompression units 423b and 423c perform the same processing.

  Next, main operations of the remultiplexing device 20, the transmission device 30, and the reception device 40 according to the present embodiment will be described.

  FIG. 17 is a flowchart showing main operations of the remultiplexing apparatus 20. The remultiplexing apparatus 20 uses the TLV packetization units 203a, 203b, 203c, and 203d to encapsulate each layer data and Lch data into variable-length TLV packets (step S11). At that time, a fixed value is stored at the head of the header area of the TLV packet.

  After that, the remultiplexing apparatus 20 configures the A layer frame obtained by framing the TLV packet of the A layer package by the layer-specific frame configuration unit 206a, and the layer-by-layer frame configuration unit 206b frames the TLV packet of the B layer package. The converted B layer frame is configured (step S12).

  Also, the remultiplexing apparatus 20 configures a symbol from the LLV package TLV packet by the L0 symbol configuration unit 208 and the L1 symbol configuration unit 209 (step S13).

  Thereafter, the XMI packet transmission scheduler 212 re-multiplexes the layer-specific frame generated in step S12 and the symbol generated in step S13 to generate an XMI packet (step S14).

  FIG. 18 is a flowchart showing main operations of the transmission apparatus 30. The transmission device 30 receives the XMI packet transmitted from the remultiplexing device 20 by the XMI packet reception unit 311 of the input interface unit 31 (step S21). The XMI packet includes a variable-length TLV packet, and a fixed value is stored in the reserved area at the head of the header area of the TLV packet.

  Thereafter, the transmitting apparatus 30 generates an A layer frame by the A layer frame generation unit 312a of the input interface unit 31, and generates a B layer frame by the B layer frame generation unit 312b (step S22).

  In addition, the transmitter 30 generates an Lch symbol by the Lch processing unit 321c of the modulation unit 32 (step S23).

  Thereafter, the transmitter 30 configures an OFDM frame from the A layer frame, the B layer frame, and the Lch symbol by the modulation unit 32, and transmits the OFDM signal (step S24).

  FIG. 19 is a flowchart showing main operations of the receiving apparatus 40. The receiving device 40 receives the OFDM signal transmitted from the transmitting device 30 by the demodulator 41 (step S31).

  Thereafter, the receiving apparatus 40 demodulates the OFDM signal by the demodulator 41 to generate A layer data and B layer data (step S32). Further, Lch data is generated by the demodulator 41 (step S33).

  After that, the receiving device 40 identifies each TLV packet from the hierarchical data generated in step S32 by the TLV packet separation units 422a and 422b of the output interface unit 42 (step S34). Further, the TLV packet separation unit 422c of the output interface unit 42 identifies the TLV packet by identifying the fixed value as the head of the TLV packet from the Lch data generated in step S33 (step S34).

  In the present embodiment, the configurations and operations of the remultiplexing device 20, the transmitting device 30, and the receiving device 40 have been described. A method for multiplexing, a method for configuring and transmitting an OFDM signal from a packet output from the remultiplexing device 20, and a method for receiving an OFDM signal transmitted from the transmitting device 30 may be used.

  Further, although not particularly mentioned in the embodiment, a program for causing a computer to execute each process performed by the remultiplexing device 20, the transmission device 30, and the reception device 40 may be provided. The program may be recorded on a computer readable medium. If a computer-readable medium is used, it can be installed on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, but may be a recording medium such as a CD-ROM or a DVD-ROM.

  Or the chip | tip mounted in the remultiplex apparatus 20, the transmission apparatus 30, and the receiving apparatus 40 may be provided. This chip includes a memory that stores a program for executing each process performed by the remultiplexing device 20, the transmission device 30, and the reception device 40, and a processor that executes the program stored in the memory.

  Although the above embodiment has been described as a representative example, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, it is possible to combine a plurality of constituent blocks described in the configuration diagram of the embodiment into one, or to divide one constituent block.

DESCRIPTION OF SYMBOLS 1 OFDM transmission / reception system 10a, 10b, 10c Multiplexer 20 Remultiplexer 30 Transmitter 31 Input interface unit 32 Modulator 33 Transmit antenna 40 Receiver 41 Demodulator 42 Output interface 43 Receive antenna 50 Demultiplexer 201a, 201b , 201c Packet filter 202a, 202b, 202c, 202d IP header compression unit 203a, 203b, 203c, 203d TLV packetization unit (packetization unit)
204a, 204b, 204c, 204d FIFO buffer 205a, 205b FEC block configuration unit 206a, 206b Hierarchical frame configuration unit 207a, 207b XMI packetization unit 208 L0 symbol configuration unit 209 L1 symbol configuration unit 210 Synchronization control XMI packet configuration unit 211 Staff XMI packet configuration unit 212 XMI packet transmission scheduler unit (transmission unit)
311 XMI packet reception unit 312a A layer frame generation unit 312b B layer frame generation unit 312c Lch frame generation unit 313 Control information / TMCC information generation unit 321a A layer processing unit 321b B layer processing unit 321c Lch processing unit 322 TMCC signal generation unit 323 Layer synthesis unit 324 Frame conversion unit 325 IFFT unit 326 Output unit 411 Input unit 412 FFT unit 413 Equalization unit 414 Layer division unit 415a A layer FEC block conversion unit 415b B layer FEC block conversion unit 416a A layer decoding unit 416b B layer decoding Unit 417 Lch demodulation unit 421a, 421b, 421c bit byte conversion unit 422a, 422b, 422c TLV packet separation unit 423a, 423b, 423c IP header decompression unit 424a, 424b Eth IF

Claims (7)

A remultiplexing device for remultiplexing a plurality of multiplexed package data for layers and multiplexed low-latency package data,
A packetizing unit for encapsulating the package data for hierarchy and the package data for low delay into variable-length first packets,
A frame configuration unit that configures a frame by layer in which the first packet of the layer package data is framed;
A symbol constituting unit constituting a symbol from the first packet of the low-latency package data;
A transmission unit that re-multiplexes the hierarchical frame and the symbol and transmits the second packet as a second packet;
The packetizing unit stores a fixed value at the head of the header area of the first packet. Transmission of receiving a second packet transmitted from a remultiplexing apparatus that remultiplexes a plurality of multiplexed package data for a hierarchy and multiplexed low-latency package data, and generates and transmits an OFDM signal A device,
An input interface unit for generating a layer-specific frame and a low-delay frame from the second packet;
A modulation unit that arranges the hierarchical frame and the low-delay frame at predetermined positions to form an OFDM frame, and transmits an OFDM signal;
The transmission apparatus, wherein the second packet includes a variable-length first packet, and a fixed value is stored at the head of the header area of the first packet. A receiving apparatus for receiving an OFDM signal including a plurality of multiplexed layer data and multiplexed low delay data,
A demodulator that demodulates the OFDM signal and generates the hierarchical data and the low-delay data;
An output interface unit that identifies and outputs a variable-length packet from the hierarchical data and the low-delay data, and
The output interface unit combines the low-delay data, searches for a fixed value, and identifies the fixed value as a head of the variable-length packet. A chip mounted on a remultiplexing device for remultiplexing a plurality of multiplexed package data for a hierarchy and multiplexed low-latency package data;
A packetizing unit for encapsulating the package data for hierarchy and the package data for low delay into variable-length first packets,
A frame configuration unit that configures a frame by layer in which the first packet of the layer package data is framed;
A symbol constituting unit constituting a symbol from the first packet of the low-latency package data;
A transmission unit that re-multiplexes the hierarchical frame and the symbol and transmits the second packet as a second packet;
The chip, wherein the packetization unit stores a fixed value at the head of the header area of the first packet. Transmission of receiving a second packet transmitted from a remultiplexing apparatus that remultiplexes a plurality of multiplexed package data for a hierarchy and multiplexed low-latency package data, and generates and transmits an OFDM signal A chip mounted on the device,
An input interface unit for generating a layer-specific frame and a low-delay frame from the second packet;
A modulation unit that arranges the hierarchical frame and the low-delay frame at predetermined positions to form an OFDM frame, and transmits an OFDM signal;
The chip, wherein the second packet includes a variable-length first packet, and a fixed value is stored at the head of the header area of the first packet. A chip mounted on a receiving apparatus that receives an OFDM signal including a plurality of multiplexed hierarchical data and multiplexed low delay data,
A demodulator that demodulates the OFDM signal and generates the hierarchical data and the low-delay data;
An output interface unit that identifies and outputs a variable-length packet from the hierarchical data and the low-delay data, and
The output interface unit combines the low-delay data, searches for a fixed value, and identifies the fixed value as the head of the variable-length packet. A program for causing a computer to function as the remultiplexing device according to claim 1.

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