JP2022071760A - Content transmission signal generation device, ofdm frame generation device and program - Google Patents

Abstract

To improve the transmission efficiency of content data.SOLUTION: A content transmission signal generation device 100 includes: a TLV generation unit 106 which generates a TLV packet; an OFDM frame configuration information generation unit 107 which generates FEC block byte offset information and TLV storage byte offset information; a synchronous control packet configuration unit 103 which generates a synchronous control packet including the FEC block byte offset information; a byte offset addition unit 108 which adds the TLV storage byte offset information to the TLV packet; a hierarchy synthesis unit 109 which synthesizes a packet of each hierarchy being input from the byte offset addition unit 108 to generate a data packet; and an insertion unit 110 which generates a content transmission signal in which a sequence number is inserted to the data packet and the synchronous control packet.SELECTED DRAWING: Figure 2

Description

The present invention relates to a content transmission signal generator, an OFDM (Orthogonal Frequency Division Multiplexing) frame generator, and a program.

In next-generation terrestrial digital broadcasting (hereinafter referred to as "next-generation terrestrial digital broadcasting"), an IP (Internet Protocol) format packet (hereinafter, "XMI") is used as a content transmission line from a performance station to a broadcasting station (transmission station). It has been studied to be transmitted by an IP line using "packet" (see, for example, Patent Document 1). "XMI" is an abbreviation for eXtensible Modulator Interface.

Japanese Unexamined Patent Publication No. 2018-78551

In the next-generation terrestrial digital experiment using XMI packets, the transmission rate of XMI when transmitting video / audio data (content data) of about 30 Mbps with SISO (Single Input Single Output) is about 50 Mbps, and MIMO (MIMO). Multiple Input Multiple Output) requires a transmission band of about 100 Mbps when transmitting content data of about 60 Mbps. That is, about 40% of the XMI packet rate will be discarded at the broadcasting station. In addition, the maximum transmission rate of STL (Studio to Transmitter Link) / TTL (Transmitter to Transmitter Link) for transmitting the content transmission signal of the current terrestrial digital broadcasting from the performance station to the broadcasting station is about 40 Mbps with the current parameter. Therefore, it is impossible to transmit the content data of the next-generation terrestrial digital broadcasting as an XMI packet using the existing STL transmitter.

An object of the present invention made in view of such circumstances is to provide a content transmission signal generation device, an OFDM frame generation device, and a program capable of improving the transmission efficiency of content data.

The content transmission signal generation device according to one embodiment is a content transmission signal generation device that transmits a content transmission signal to an OFDM frame generation device, and encapsulates a packet of a content signal for each layer into a variable length TLV packet. The TLV conversion unit that generates the TLV packet, the FEC block byte offset information indicating the byte offset from the beginning of the OFDM frame of the FEC block in the OFDM frame configured by the OFDM frame generator, and the storage location of the TLV packet in the FEC block. The OFDM frame configuration information generation unit that generates the TLV storage byte offset information indicating the above, the synchronization control packet configuration unit that generates the synchronization control packet including the FEC block byte offset information, and the TLV storage byte offset for the TLV packet. A byte offset addition unit that adds information, a layer synthesis unit that synthesizes packets of each layer input from the byte offset addition unit to generate a data packet, and a sequence number for the data packet and the synchronization control packet. It includes an insertion unit that generates an inserted content transmission signal.

Further, in one embodiment, the insertion unit further inserts a delivery time stamp indicating the transmission time of the synchronization control packet from the content transmission signal generation device into the synchronization control packet, and inserts the delivery time stamp into the data packet. Further, a delivery time stamp indicating the transmission time of the data packet from the content transmission signal generation device may be inserted.

Further, in one embodiment, the insertion unit further inserts a first delivery time stamp indicating the transmission time of the synchronization control packet from the content transmission signal generation device into the synchronization control packet, and the data packet. Further, a second delivery time stamp indicating the difference between the transmission times of the data packet and the synchronization control packet from the content transmission signal generation device may be inserted.

Further, in one embodiment, the insertion unit may further insert packet type information for determining whether the data packet is a synchronization control packet or a data packet into the data packet and the synchronization control packet.

Further, in one embodiment, the packet of the content signal according to the layer may be an MMTP / IP packet in which an MMTP packet, which is an MMT format packet, is stored in an IP packet.

Further, the OFDM frame generation device according to the embodiment is an OFDM frame generation device that receives the content transmission signal from the content transmission signal generation device, prepares an FEC block area, and is based on the TLV storage byte offset information. Then, based on the FEC block byte offset information and the TLV mapping unit that maps the TLV packet to the FEC block area, the FEC block that concatenates the TLV packet and stores it in the main signal area is formed for one OFDM frame. A block forming unit, a data processing unit that performs error correction coding processing and interleaving processing on the FEC block, and a TMCC signal and a pilot signal are inserted into the data processed by the data processing unit to form an OFDM frame. It includes an OFDM frame component.

Further, the program according to the embodiment causes the computer to function as the content transmission signal generation device.

Further, the program according to the embodiment causes the computer to function as the OFDM frame generation device.

According to the present invention, it is possible to improve the transmission efficiency of content data.

It is a block diagram which shows the structural example of the distribution system which concerns on one Embodiment of this invention. It is a block diagram which shows the structural example of the content transmission signal generation apparatus which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the TLV packet generated by the content transmission signal generation apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the operation example of the content transmission signal generation apparatus which concerns on one Embodiment of this invention. It is a figure which shows the packet structure of the conventional XMI packet. It is a figure which shows the conventional FEC block and OFDM frame. It is a figure which shows the packet composition example of the content transmission signal generated by the transmission signal generation apparatus which concerns on one Embodiment of this invention. It is a figure which shows the example which makes the content transmission signal generated by the transmission signal generation apparatus which concerns on one Embodiment of this invention a fixed length. It is a block diagram which shows the structural example of the OFDM frame generation apparatus which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the FEC block generated by the OFDM frame generation apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the operation example of the OFDM frame generation of the OFDM frame generation apparatus which concerns on one Embodiment of this invention.

Hereinafter, one embodiment will be described in detail with reference to the drawings.

(Distribution system)
FIG. 1 is a diagram showing a configuration example of a distribution system 1 according to an embodiment of the present invention. The distribution system 1 shown in FIG. 1 includes a performance station 10 and a broadcasting station 20. The playing place 10 includes a multiplexing device 11 (11a to 11c), a remultiplexing device 12, and an STL transmitter 13. The broadcasting station 20 includes an STL receiver 21, a packet monitoring device 22, a traffic smoother 23, a modulation device 24, and a transmitter 25. The performance station 10 and the broadcasting station 20 are connected to each other via a content transmission line 30 as a network.

The multiplexing device 11a multiplexes the content signals (video / audio signals and subtitle signals) for the A layer input from the outside, packetizes them into packets of a predetermined format, and makes the remultiplexing device 12 as a package for the A layer. Output. In the present embodiment, the multiplexing device 11 generates an MMTP (MMT Protocol) packet, which is an MMT (MPEG Media Transport) format packet.

Similarly, the multiplexing device 11b multiplexes the content signal for the B layer input from the outside, packets it into a packet of a predetermined format, and outputs it to the remultiplexing device 12 as a package for the B layer. The multiplexing device 11c multiplexes the content signal for the C layer input from the outside, packets it into a packet of a predetermined format, and outputs it to the remultiplexing device 12 as a package for the C layer.

The transmission line between the multiplexing device 11 and the remultiplexing device 12 is an IP (Internet Protocol) transmission line. For example, the multiplexing device 11 stores an MMTP packet in an IP packet and remultiplexes it as an MMTP / IP packet. Output to the conversion device 12.

The remultiplexing device 12 remultiplexes the plurality of hierarchical package data multiplexed by the multiplexing devices 11a, 11b, 11c into one system and outputs the data to the STL transmitter 13.

The STL transmitter 13 transmits the content transmission signal to the broadcasting station 20 via the content transmission line 30.

The STL receiver 21 receives the content transmission signal from the performance center 10 via the content transmission line 30.

The packet monitoring device 22 monitors the transmission delay of the packet to stabilize broadcasting. For example, the packet monitoring device 22 monitors the time stamp of the packet. This time stamp functions as a time stamp indicating a transmission time that is a reference for the time when the traffic smoother 23 should transmit the packet. The broadcasting station 20 does not necessarily have to include the packet monitoring device 22.

The traffic smoother 23 outputs packets at regular intervals with accurate time stamps. For example, the traffic smoother 23 corrects a packet time stamp using time information acquired from an external GPS (Global Positioning System) server, PTP (Precision Time Protocol) server, NTP (Network Time Protocol) server, or the like. .. Then, the traffic smoother 23 outputs the time-stamped packet to the modulation device 24 at the transmission time indicated by the corrected time stamp. The traffic smoother 23 does not have to be a dedicated device and may be in the form of computer software. Further, the packet monitoring device 22 may include a traffic smoother 23. The broadcasting station 20 does not necessarily have to include the traffic smoother 23.

The modulation device 24 modulates the time-stamped packet input from the traffic smoother 23 and outputs it to the transmitter 25.

The transmitter 25 generates a broadcast wave corresponding to the packet input from the modulation device 24 and transmits the broadcast wave to the outside of the broadcast station 20 via the antenna.

(Content transmission signal generator)
Next, the content transmission signal generation device 100 according to the embodiment of the present invention will be described. The content transmission signal generation device 100 is incorporated into the remultiplexing device 12 or the equipment associated with the function of the remultiplexing device 12. The content transmission signal generation device 100 does not have to be dedicated hardware, and may be in the form of computer software.

In the conventional content transmission signal generation device (remultiplexing device), a TLV packet is generated, an FEC block and an OFDM frame are configured from the TLV packet, and the OFDM frame is divided into XMI packets. On the other hand, the content transmission signal generation device 100 generates a TLV packet and then generates a content transmission signal without generating an FEC block. The content transmission signal generation device 100 generates a content transmission signal and transmits it to an OFDM frame generation device described later.

FIG. 2 is a block diagram showing a configuration example of the content transmission signal generation device 100. The content transmission signal generation device 100 shown in FIG. 2 includes a frame time generation unit 101, a TMCC (Transmission Multiplexing Configuration Control) generation unit 102, a synchronization control packet configuration unit 103, a layer separation unit 104, and an IP header compression unit 105. A TLV (Type Length Value) conversion unit 106, an OFDM frame configuration information generation unit 107, a byte offset addition unit 108, a layer composition unit 109, and an insertion unit 110 are provided.

The frame time generation unit 101 generates frame cycle information indicating the period of the OFDM frame and time information indicating the time based on PTP (Precision Time Protocol) / NTP (Network Time Protocol) input from the outside. Then, the frame time generation unit 101 outputs the frame cycle information to the synchronization control packet configuration unit 103, and outputs the time information to the insertion unit 110. The time information is shown in, for example, NTP (Network Time Protocol) format.

The TMCC generation unit 102 generates TMCC information based on setting information (parameters of the modulation device 24, delay control information of the relay station, etc.) input from the outside, and outputs the TMCC information to the synchronization control packet configuration unit 103.

The synchronization control packet configuration unit 103 is an OFDM frame start instruction (OFDM frame start instruction) which is information indicating the start point of the OFDM frame from the TMCC information generated by the TMCC generation unit 102 and the frame period information obtained from the frame time generation unit 101. For example, 1 OFDM cycle flag information) is generated and output to the OFDM frame configuration information generation unit 107.

Further, the synchronization control packet configuration unit 103 generates a synchronization control packet storing the synchronization control information of the OFDM frame and outputs the synchronization control packet to the insertion unit 110. The synchronization control packet includes FEC block byte offset information obtained from the OFDM frame configuration information generation unit 107. The details of the synchronization control packet will be described later.

The layer separation unit 104 inputs an MMTP / IP packet of the content signal output from a transmission facility such as a master of the playing room 10, performs layer separation according to the packet type, and outputs the MMTP / IP packet to the IP header compression unit 105. In the present embodiment, the layer separation unit 104 is divided into three layers, A layer, B layer, and C layer.

The IP header compression unit 105 compresses the IP header of the MMTP / IP packet input from the layer separation unit 104 as necessary, and outputs the MMTP / IP packet to the TLV conversion unit 106.

The TLV conversion unit 106 encapsulates the packet input from the IP header compression unit 105 into a variable length TLV (Type Length Value) packet to generate a TLV packet, and outputs the TLV packet to the byte offset addition unit 108. Further, the TLV conversion unit 106 outputs the packet length information of the TLV packet to the OFDM frame configuration information generation unit 107.

FIG. 3 is a diagram showing a configuration example of a TLV packet. In the following, the numbers attached to each field 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, a data length, and a data area. The packet type indicates the type of TLV packet. Depending on the packet type, it is possible to specify whether the data is in the A layer, the B layer, or the C layer. The data length indicates the size of the data stored in the data area. The TLV conversion unit 106 stores the IP packet input from the IP header compression unit 105 in the data area. As for the reserved area, for example, all the bits may be set to "1".

The OFDM frame configuration information generation unit 107 is based on the transmission mode, GI (Guard interval) ratio, TMCC information, etc. obtained from the setting information, and the OFDM frame start instruction input from the synchronization control packet configuration unit 103. FEC block byte offset information (for example, 3-byte information) indicating the byte offset from the beginning of the OFDM frame of the FEC block in the OFDM frame composed of 20 is generated and output to the synchronization control packet configuration unit 103. The FEC block byte offset information may be information indicating a byte offset from the beginning of the OFDM frame of the FEC block when the OFDM frame is not straddled.

Further, the OFDM frame configuration information generation unit 107 is based on the code length and coding rate (coding setting information) obtained from the setting information and the packet length information of the TLV packet obtained from the TLV conversion unit 106. , Obtains information on the length of the LDPC parity section and the FEC block length, generates TLV storage byte offset information (for example, 3-byte information) indicating the storage location of the TLV packet in the FEC block, and outputs it to the byte offset addition section 108. do.

The byte offset addition unit 108 adds the TLV storage byte offset information input from the OFDM frame configuration information generation unit 107 to the TLV packet input from the TLV conversion unit 106, and outputs the TLV storage byte offset information to the layer synthesis unit 109.

The layer synthesizing unit 109 synthesizes the packets of each layer input from the byte offset addition unit 108 to generate a data packet, and outputs the data packet to the insertion unit 110. The details of the data packet will be described later.

The insertion unit 110 outputs a content transmission signal in which a sequence number and packet type information are inserted to the outside of the content transmission signal generation device 100 with respect to the synchronization control packet input from the synchronization control packet configuration unit 103. The packet type information is information for determining whether the packet is a synchronization control packet in which synchronization control information is stored or a data packet in which data is stored. The insertion unit 110 further inserts a delivery time stamp (first delivery time stamp) indicating the transmission time of the synchronization control packet from the content transmission signal generation device 100 into the synchronization control packet input from the synchronization control packet configuration unit 103. You may.

Further, the insertion unit 110 outputs the content transmission signal in which the sequence number and the packet type information are inserted to the data packet input from the layer synthesis unit 109 to the outside of the content transmission signal generation device 100. The insertion unit 110 transmits one synchronization control packet at the beginning every 1 OFDM time, and then transmits a plurality of data packets. The insertion unit 110 may further insert a delivery time stamp (first delivery time stamp) indicating the transmission time of the data packet from the content transmission signal generation device 100 into the data packet input from the layer synthesis unit 109. .. Alternatively, the insertion unit 110 further sets the transmission time of the synchronization control packet from the content transmission signal generation device 100 and the transmission time of the data packet from the content transmission signal generation device 100 for the data packet input from the layer synthesis unit 109. A delivery time stamp (second delivery time stamp) indicating the difference after the decimal point of is may be inserted.

Next, the operation of the content transmission signal generation device 100 will be described with reference to FIG. FIG. 4 is a flowchart showing an operation example of the content transmission signal generation device 100.

In step S101, PTP / NTP is input and frame period information and time information are generated.

In step S102, setting information is input and TMCC information is generated.

In step S103, an OFDM frame start instruction is generated.

In step S104, the MMTP / IP packet of the content signal is input and layer separation is performed.

In step S105, the IP header is compressed for the MMTP / IP packet.

In step S106, a TLV packet is generated.

In step S107, FEC block byte offset information is generated based on the OFDM frame start instruction generated in step S103 and the packet length of the TLV packet generated in step S106.

In step S108, a synchronization control packet is configured.

In step S109, TLV storage byte offset information is added to the TLV packet to form a data packet.

In step S110, sequence numbers are inserted into and output to the synchronization control packet configured in step S108 and the data packet configured in step S109, respectively. Further, the packet type information and the delivery time stamp may be inserted into the synchronization control packet and the data packet, respectively.

FIG. 5 shows a packet configuration of a conventional XMI packet for comparison with the present invention. The conventional XMI packet includes an IPv4 header, a UDP header, a MMTP packet header (MMTP header), and an XMI header as headers. The conventional XMI packets include an XMI packet in which the data area shown in FIG. 5A contains synchronization control information, an XMI packet in which only data is contained in the data area shown in FIG. 5B, and FIG. There are four types: an XMI packet in which the data area shown in (c) contains data and stuff bits, and an XMI packet in which the data area shown in FIG. 5 (d) is composed of stuff bits.

As shown in FIG. 5, in order to maintain a fixed length of an XMI packet, stuffing is performed by adding a stuff bit to a data unit that is less than the synchronization control information or the packet length. Further, when the data does not exist, the staff bit is sent as shown in FIG. 5 (d) so that the rate becomes constant. However, in this configuration, since the parity area of the FEC block is filled with nulls, useless packets are sent to the line, and there is a risk of an increase in the transmission rate and packet loss in the line.

FIG. 6 is a diagram showing a conventional FEC block and an OFDM frame. Here, an example of a coding rate of 7/16 and a code length of Middle is shown. In this case, the LDPC parity occupies 9/16 (4860 bytes) of the 8640 bytes of the FEC block, which is a wasteful signal.

Therefore, FIG. 7 shows a packet configuration example of the content transmission signal according to the embodiment of the present invention. 7 (a) shows a synchronization control packet of the content transmission signal, FIG. 7 (b) shows the first example of the data packet of the content transmission signal, and FIG. 7 (c) shows the content transmission signal. A second example of a data packet is shown.

The synchronization control packet and the data packet include an IPv4 header, a UDP header, packet type information, a reserved area, a sequence number, and a delivery time stamp. The packet type information, the sequence number, and the delivery time stamp are inserted by the insertion unit 110. The packet type information and the sequence number are included in the XMI header in the conventional XMI packet.

The synchronization control packet shown in FIG. 7A includes synchronization control information. The synchronization control information includes FEC block byte offset information indicating a byte offset from the beginning of the OFDM frame of the FEC block generated by the OFDM frame configuration information generation unit 107. This makes it possible to configure the FEC block on the broadcasting station 20 side that has received the content transmission signal. Further, the synchronization control information includes TMCC information, time information indicating a time when the next OFDM frame should be transmitted, and the like.

Further, the data packets shown in FIGS. 7 (b) and 7 (c) are the TLV storage byte offset information generated by the byte offset addition unit 108, the synchronization signal, and the TLV packet (TLV converted) generated by the TLV conversion unit 106. Data), including. By transmitting the input IP packet in the TLV format without stuffing the data packet to a fixed length, it is possible to streamline the packet. By placing the TLV storage byte offset information before the TLV packet and obtaining the byte offset information from the beginning of the OFDM frame, it is possible to know the beginning of the OFDM frame.

The plurality of broadcasting stations 20 can form FEC blocks and OFDM frames by receiving synchronization control packets and data packets. Further, it is possible to guarantee the generation of the same waveform at the timing for realizing SFN (Single Frequency Network).

As shown in FIG. 8, the content transmission signal may be stuffed to the end of the packet to have a fixed length. Further, when the actual data does not exist, the constant rate may be obtained by filling the TLV storage byte offset or less with the stuff bits. Further, if the modulation device 24 is to recognize at what byte of the packet the TLV starts, the TLV synchronization signal (for example, 0x7f) does not have to be transmitted. The number of bytes shown in FIG. 8 is an example. For example, in the case of the above-mentioned first delivery time stamp, the delivery time stamp may be stored in the upper 4 bytes above the decimal point and stored in the lower 4 bytes after the decimal point, and may be stored in the lower 4 bytes of the above-mentioned second delivery time stamp. In that case, only the decimal point may be stored in 4 bytes.

(OFDM frame generator)
Next, the OFDM frame generation device 200 according to the embodiment of the present invention will be described. The OFDM frame generation device 200 is incorporated in the STL receiver 21, the packet monitoring device 22, the traffic smoother 23, or the modulation device 24. The OFDM frame generator 200 does not have to be dedicated hardware and may be in the form of computer software.

The OFDM frame generation device 200 receives the content transmission signal from the content transmission signal generation device 100 and generates an OFDM frame.

FIG. 9 is a block diagram showing a configuration example of the OFDM frame generation device 200. The OFDM frame generation device 200 shown in FIG. 9 includes a packet filter unit 201, a layer separation unit 202, a TLV mapping unit 203, an FEC block forming unit 204, an energy diffusion unit 205, an error correction coding unit 206, and an error correction coding unit 206. The bit interleaving unit 207, the mapping unit 208, the layer synthesis unit 209, the frame header addition unit 210, the time / frequency interleaving unit 211, the TMCC analysis unit 212, the LLch modulation unit 213, and the pilot signal generation unit 214. , An OFDM frame configuration unit 215 and an OFDM transmission processing unit 216.

The packet filter unit 201 removes the IPv4 header and the UDP header of the content transmission signal (synchronization control packet and data packet) received from the content transmission signal generation device 100, and outputs the content transmission signal to the layer separation unit 202.

The layer separation unit 202 separates packets belonging to each layer and distributes them to the processing system of each layer. Further, the channel data (for example, Earthquake Early Warning) transmitted with a lower delay (Low Latency) as compared with each layer is output to the LLch modulation unit 213. Further, the layer separation unit 202 outputs the synchronization control information included in the synchronization control packet to the TMCC analysis unit 212.

The TLV mapping unit 203 prepares an FEC block area, maps the TLV packet to the FEC block area based on the TLV storage byte offset information included in the data packet, and outputs the TLV packet to the FEC block forming unit 204.

The FEC block forming unit 204 forms an FEC block stored in the main signal area by concatenating TLV packets based on the FEC block byte offset information included in the synchronization control packet for one OFDM frame, and outputs the FEC block to the energy spreading unit 205. ..

FIG. 10 is a diagram showing a configuration example of the FEC block. As shown in FIG. 10, the FEC block includes an FEC block header, a main signal area, a BCH parity area, and an LDPC parity area.

The FEC block header is information indicating the position of the head of the first TLV packet stored in the main signal area of the FEC block by the number of bytes from the head of the FEC block excluding the FEC block header.

Three types of sizes of the FEC block are set according to the code length (Short, Middle, Long) of LDPC (Low Density Parity Check) coding performed by the transmitter 25. Further, the sizes of the main signal area, the stuff bit area, and the LDPC parity area are determined according to the coding rate. The BCH parity region is determined according to the code length.

The energy diffusion unit 205 performs energy diffusion processing on the FEC block input from the FEC block forming unit 204, and outputs the energy diffusion unit to the error correction coding unit 206.

The error correction coding unit 206 performs error correction coding (LDPC coding in this embodiment) of the signal input from the energy diffusion unit 205 in order to enable the receiving side to correct the transmission error, and generates a coded signal. do. Then, the error correction coding unit 206 outputs the generated coded signal to the bit interleaving unit 207.

The bit interleaving unit 207 generates bit data by interleaving the coded signal input from the error correction coding unit 206 bit by bit in order to improve the performance of the error correction code. Then, the bit interleaving unit 207 outputs the generated bit data to the mapping unit 208.

The mapping unit 208 maps the bit data input from the bit interleaving unit 207 to the IQ plane, and generates a carrier symbol with carrier modulation according to the modulation method. Then, the mapping unit 208 outputs the generated carrier symbol to the layer synthesis unit 209.

The layer synthesizing unit 209 synthesizes carrier symbols input from the mapping unit 208 of each layer and outputs them to the frame header addition unit 210.

The frame header addition unit 210 adds a frame header to the carrier symbol input from the layer composition unit 209, and outputs the frame header to the time / frequency interleave unit 211.

The time / frequency interleaving unit 211 rearranges the order of the carrier symbols input from the frame header addition unit 210 in the time direction and the frequency direction to generate an interleaved signal. Then, the time / frequency interleaving unit 211 outputs the generated interleaving signal to the OFDM frame component unit 215.

The TMCC analysis unit 212 generates a TMCC signal from the synchronization control information input from the layer separation unit 202 and outputs the TMCC signal to the OFDM frame configuration unit 215.

The LLch modulation unit 213 modulates the data input from the layer separation unit 202 by a predetermined modulation method (for example, DBPSK) to generate a symbol, and outputs the symbol to the OFDM frame configuration unit 215.

The pilot signal generation unit 214 generates a pilot signal (SP signal and CP signal) and outputs the pilot signal to the OFDM frame configuration unit 215.

The OFDM frame configuration unit 215 uses the interleave signal input from the time / frequency interleave unit 211, the TMCC signal input from the TMCC analysis unit 212, the symbol input from the LLch modulation unit 213, and the pilot signal input from the pilot signal generation unit 214. Is inserted to form an OFDM frame. Then, the OFDM frame configuration unit 215 outputs the generated OFDM frame to the OFDM transmission processing unit 216.

The OFDM transmission processing unit 216 performs OFDM modulation processing on the OFDM frame input from the OFDM frame configuration unit 215 to generate an OFDM signal, and transmits the generated OFDM signal to the receiving device. More specifically, the OFDM transmission processing unit 216 performs IFFT (Inverse Fast Fourier Transform) processing on the OFDM symbol of the OFDM frame input from the OFDM frame configuration unit 215 to be an effective symbol in the time region. Generate a signal. Then, the OFDM transmission processing unit 216 inserts a guard section at the beginning of the effective symbol signal, and then performs quadrature modulation processing and D / A conversion processing to generate an OFDM signal.

Next, the operation of OFDM frame generation of the OFDM frame generator 200 will be described with reference to FIG. FIG. 11 is a flowchart showing an operation example of OFDM frame generation of the OFDM frame generation device 200.

In step S201, the TLV packet is input and the generation of the OFDM frame is started based on the TMCC information.

In step S202, the generation of the FEC block is started. That is, an FEC block area is prepared.

In step S203, the TLV packet is mapped based on the TLV storage byte offset information included in the data packet.

In step S204, it is determined whether or not the configuration of the FEC block area is completed. If the configuration of the FEC block area is not completed, the process returns to step S203, and if the configuration of the FEC block area is completed, the process proceeds to step S205.

In step S205, it is determined whether or not the configuration of the OFDM frame is completed. That is, it is determined whether or not the FEC block area corresponding to the capacity of 1 OFDM frame is filled with TLV packets. If the configuration of the OFDM frame is not completed, the process is returned to step S202, and if the configuration of the FEC block area is completed, the process is returned to step S201 to configure a new OFDM frame.

(program)
It is also possible to use a computer capable of executing program instructions in order to function as the content transmission signal generation device 100 or the OFDM frame generation device 200. The computer stores a program describing the processing contents that realize each function of the content transmission signal generation device 100 or the OFDM frame generation device 200 in the storage unit of the computer, and the processor of the computer reads and executes this program. do. Some of these processing contents may be realized by hardware. Here, the computer may be a general-purpose computer, a dedicated computer, a workstation, a PC (Personal Computer), an electronic notepad, or the like. The program instruction may be a program code, a code segment, or the like for executing a necessary task. The processor may be a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), or the like.

The program may also be recorded on a computer-readable recording medium. Using such a recording medium, it is possible to install the program on the computer. Here, the recording medium on which the program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, but may be, for example, a recording medium such as a CD-ROM or a DVD-ROM. The program can also be provided by download over the network.

As described above, in the present invention, the content is transmitted in a slim packet configuration, and the FEC block and the OFDM frame are generated on the broadcasting station 20 (OFDM frame generator 200) side, so that the transmission rate is set to video. It is possible to transmit at a rate close to the data capacity of the original audio data. Therefore, it is possible to transmit the content data of the next-generation terrestrial digital broadcasting by using the same transmission parameters as the existing STL transmitter and STL receiver.

Further, by putting a delivery time stamp on the synchronization control packet and transmitting the difference time after the decimal point on all the data packets, it is possible to generate and synchronize the clock with reference to the absolute time. Then, it is possible to configure an OFDM frame having the same waveform that can be SFN constructed in the broadcasting station 20 (OFDM frame generator 200).

Further, since the content transmission signal has a sequence number in the header portion of the packet, it is possible to apply a conventional error correction technique such as Pro-MPEG.

Although the above embodiments have been described as typical examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present invention. Therefore, the invention should not be construed as limiting by the embodiments described above, and various modifications or modifications can be made without departing from the claims. For example, it is possible to integrate a plurality of constituent blocks described in the configuration diagram of the embodiment or to divide one constituent block. Further, instead of executing the plurality of steps described in the flowchart of the embodiment in chronological order according to the description, the steps are executed in parallel or in a different order according to the processing capacity of the device that executes each step, or as necessary. It may be executed.

1 Distribution system 10 Performance station 11 Multiplexing device 12 Remultiplexing device 13 STL transmitter 20 Broadcasting station 21 STL receiver 22 Packet monitoring device 23 Traffic smoother 24 Modulator 25 Transmitter 30 Content transmission line 100 Content transmission signal generator 101 Frame time generation unit 102 TMCC generation unit 103 Synchronization control packet configuration unit 104 Layer separation unit 105 IP header compression unit 106 TLV conversion unit 107 OFDM frame configuration information generation unit 108 byte offset addition unit 109 Layer composition unit 110 Insertion unit 200 OFDM frame generation Device 201 Packet filter part 202 Hierarchical separation part 203 TLV mapping part 204 FEC block forming part 205 Energy diffusion part 206 Error correction coding part 207 Bit interleaving part 208 Mapping part 209 Hierarchy synthesis part 210 Frame header addition part 211 Time / frequency interleaving part 212 TMCC analysis unit 213 LLch modulation unit 214 Pilot signal generation unit 215 OFDM frame configuration unit 216 OFDM transmission processing unit

Claims (8)

A content transmission signal generator that transmits a content transmission signal to an OFDM frame generator.
A TLV conversion unit that encapsulates a packet of a content signal for each layer into a variable-length TLV packet to generate a TLV packet, and
Generates FEC block byte offset information indicating the byte offset from the beginning of the OFDM frame of the FEC block in the OFDM frame configured by the OFDM frame generator, and TLV stored byte offset information indicating the storage location of the TLV packet in the FEC block. The OFDM frame configuration information generator and
A synchronization control packet component that generates a synchronization control packet including the FEC block byte offset information, and
A byte offset addition unit that adds the TLV storage byte offset information to the TLV packet,
A layer synthesizing unit that synthesizes packets of each layer input from the byte offset addition unit to generate a data packet, and a layer synthesizing unit.
An insertion unit that generates a content transmission signal in which a sequence number is inserted into the data packet and the synchronization control packet, and an insertion unit.
A content transmission signal generator. The insertion part is
Further, a delivery time stamp indicating the transmission time of the synchronization control packet from the content transmission signal generator is inserted into the synchronization control packet.
The content transmission signal generation device according to claim 1, further comprising a delivery time stamp indicating the transmission time of the data packet from the content transmission signal generation device to the data packet. The insertion part is
Further, a first delivery time stamp indicating the transmission time of the synchronization control packet from the content transmission signal generator is inserted into the synchronization control packet.
The content transmission signal generation according to claim 1, further comprising a second delivery time stamp indicating the difference in transmission time between the data packet and the synchronization control packet from the content transmission signal generator. Device. The insertion unit further inserts packet type information for determining whether the packet is a synchronization control packet or a data packet into the data packet and the synchronization control packet, according to any one of claims 1 to 3. The described content transmission signal generator. The content transmission signal generation device according to any one of claims 1 to 4, wherein the packet of the content signal according to the layer is an MMTP / IP packet in which an MMTP packet, which is an MMT format packet, is stored in an IP packet. .. An OFDM frame generator that receives the content transmission signal from the content transmission signal generator according to any one of claims 1 to 5.
A TLV mapping unit that prepares an FEC block area and maps the TLV packet to the FEC block area based on the TLV storage byte offset information.
Based on the FEC block byte offset information, the FEC block forming unit that concatenates the TLV packets and forms the FEC block stored in the main signal region for one OFDM frame, and the FEC block forming unit.
A data processing unit that performs error correction coding processing and interleaving processing on the FEC block, and
An OFDM frame component unit that inserts a TMCC signal and a pilot signal into the data processed by the data processing unit to form an OFDM frame, and an OFDM frame component unit.
An OFDM frame generator. A program for causing a computer to function as the content transmission signal generator according to any one of claims 1 to 5. A program for operating a computer as the OFDM frame generator according to claim 6.

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