JP2023161477A - Transmitting device, receiving device, and program - Google Patents

Abstract

To improve frequency usage efficiency in a distribution system.SOLUTION: A transmitting device 30 includes an LDPC encoding unit 38 that performs LDPC encoding on packets containing emergency information and generates fixed-length LDPC codes, a combining unit 39 that generates a combined packet in which packets containing general-purpose information are combined with a plurality of LDPC codes, and an OFDM frame configuration unit 40 that allocates the combined packet to an LLch carrier that is a subcarrier for an LLch.SELECTED DRAWING: Figure 5

Description

The present invention relates to a transmitting device, a receiving device, and a program.

In advanced terrestrial broadcasting systems, a low-delay transmission channel called LLch (Low Latency channel) is being considered. Specifically, subcarriers (LLch carriers) whose modulation method is DBPSK (Differential Binary Phase Shift Keying) without time interleaving processing are randomly arranged within the signal band. This subcarrier has low delay and high noise tolerance compared to data transmission such as video and audio. Therefore, it is suitable for transmitting highly urgent and important information such as emergency earthquake early warnings, and is designed to match the data length of earthquake motion warning information specified by ISDB-T (Integrated Services Digital Broadcasting-Terrestrial). Low-Density Parity-Check) code (see, for example, Patent Document 1 and Non-Patent Document 1).

JP2021-93727A

Asakura et al., “A study of low-latency, high-tolerance transmission for the advancement of terrestrial broadcasting,” IEICE technical research report, RCS2021-167, November 2021

Unlike main line data such as video and audio, LLch aligns the beginning of the LDPC code with the beginning of the OFDM (Orthogonal Frequency Division Multiplexing) frame, and synchronizes the code by OFDM frame synchronization in order to perform as low-latency processing as possible for the transmission of emergency information. The method is to take the following. Therefore, surplus bits smaller than 1LDPC code occur. Conventionally, these extra bits were filled in as nulls, and could not be used effectively.

An object of the present invention, which has been made in view of the above circumstances, is to provide a transmitting device, a receiving device, and a program that can improve frequency usage efficiency in a distribution system.

In order to solve the above problems, a transmitting device according to an embodiment is a transmitting device that transmits transmission data using LLch, the transmission data includes emergency information and general-purpose information, and the transmission device includes packets containing the emergency information. an LDPC encoding unit that performs LDPC encoding on a plurality of LDPC codes to generate a fixed-length LDPC code; a combining unit that generates a combined packet in which a plurality of the LDPC codes are combined with a packet containing the general-purpose information; An OFDM frame configuration unit that allocates to an LLch carrier that is a subcarrier for LLch.

Furthermore, in one embodiment, the OFDM frame configuring unit may include a LLch carrier symbol of a packet including the general-purpose information in a surplus area when a plurality of LLch carrier symbols of the LDPC code are allocated to the LLch carrier in one OFDM frame. may be assigned.

Further, in one embodiment, the size of the packet containing the general information may be determined based on transmission parameters.

Moreover, in order to solve the above-mentioned problem, a receiving device according to one embodiment is a receiving device that receives transmission data using LLch, and the transmission data includes emergency information and general-purpose information, and includes LLch carrier symbols. an LLch demodulator that generates a combined packet in which a plurality of LDPC codes obtained by LDPC encoding the packet containing the emergency information and the packet containing the general-purpose information are combined by demodulating with a predetermined modulation method; The information determining unit extracts a packet including the LDPC code and the general-purpose information from a packet, and the LDPC decoding unit performs LDPC decoding on the LDPC code.

Further, in one embodiment, the information determining unit may determine the LDPC code and the general-purpose information based on the number of LDPC codes of the packet containing the emergency information.

Furthermore, in one embodiment, the number of LDPC codes of the packet including the emergency information may be determined based on transmission parameters.

Further, a program according to an embodiment causes a computer to function as the transmitting device.

Further, a program according to an embodiment causes a computer to function as the receiving device.

According to the present invention, it is possible to improve frequency usage efficiency in a distribution system.

FIG. 1 is a block diagram illustrating a configuration example of a distribution system according to an embodiment. FIG. 3 is a diagram showing an example of the structure of a TLV packet and an LDPC code of LLch data. FIG. 2 is a block diagram illustrating a configuration example of an LLch packet generation unit according to an embodiment. FIG. 3 is a diagram illustrating an example of general-purpose data TLV packet size for each transmission parameter. FIG. 1 is a block diagram illustrating a configuration example of a transmitting device according to an embodiment. FIG. 1 is a block diagram illustrating a configuration example of a receiving device according to an embodiment. FIG. 2 is a block diagram illustrating a configuration example of an information determining unit according to an embodiment. FIG. 3 is a diagram illustrating an example of general-purpose data TLV packet positions for each transmission parameter.

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

(Distribution system)
FIG. 1 is a block 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 multiplexing device 10 (10a to 10c), a remultiplexing device 20, a transmitting device 30, and a receiving device 50. In FIG. 1, data in three layers, A layer, B layer, and C layer, is transmitted, but the number of layers in layer transmission is not limited to three layers.

Furthermore, the distribution system 1 provides a low-latency transmission channel (LLch) that does not perform processing such as time interleaving, so that data can be transmitted with low delay. Conventionally, only emergency information such as earthquake information was handled as LLch data, but the present invention also handles general-purpose information. The general-purpose information may be any information, for example, information used by a broadcaster to control a relay station, such as relay station delay time settings.

Each of the multiplexing devices 10 multiplexes externally input content signals for each layer (video/audio signals and subtitle signals), packetizes them into packets in a predetermined format, and sends each layer data to the re-multiplexing device 20. Output.

The remultiplexing device 20 remultiplexes each layer data and LLch data input from each multiplexing device 10 into one system, and outputs the remultiplexed data to the transmitting device 30. The packets output by the remultiplexing device 20 may be in TLV (Type Length Value)/IP packet format, or may be in other packet formats such as XMI (eXtensible Modulator Interface) packet format. In this embodiment, an example of the TLV/IP packet format will be explained.

FIG. 2 is a diagram showing an example of the structure of the TLV packet and LDPC code of LLch data. The TLV header includes a reserved area, a packet type, and a data length. The packet type indicates a packet type that specifies whether the TLV packet is IPv4, IPv6, compressed IP, or the like. The data length indicates the size of data stored in the payload. For the reserved area, for example, all bits may be set to "1". For the specifications of TLV packets, please refer to the following reference documents, for example.
References: Radio Industries Association, “Video coding, audio coding and multiplexing methods in digital broadcasting”, ARIB STD-B32 v3.11, July 2018

Byte alignment is added to make the TLV packet a multiple of 8 bits. Conventionally, the 7-bit byte alignment is fixed to, for example, "1111111". However, since the byte alignment bits are redundant bits, a part of the conventional 7-bit byte alignment can be used as a transmission data type signal. Therefore, in this embodiment, a part of the byte alignment is used as a transmission data type signal.

In this way, by setting the total of the transmission data type signal and the byte alignment bit to 7 bits, it is possible to make the length the same as the conventional TLV packet. In addition, by utilizing surplus bits that were not used for transmission (byte alignment bits), it becomes possible to transmit additional information bits without changing the data length or coding rate, improving transmission efficiency. .

Since n bits (3 bits in FIG. 2) are used as a transmission data type signal, the remaining (7-n) bits are used for byte alignment. The payload indicates emergency information or general-purpose information. In the example shown in FIG. 2, the emergency information is classified into earthquake information (earthquake early warning EEW), disaster information, and emergency information. Since LLch has a limited transmission capacity, it is not possible to transmit all information at once. Therefore, it is necessary to determine the transmission data type based on the transmission data type signal for each transmitted packet. Since general-purpose information is not information that requires immediacy, the data to be sent can be divided and sent multiple times.

Hereinafter, among the LLch packets, a TLV packet containing emergency information will be referred to as an "emergency data TLV packet", and a TLV packet containing general-purpose information will be referred to as a "general-purpose data TLV packet". The emergency data TLV packet is the same as the conventional LLch packet. The size of the emergency data TLV packet (urgent data TLV packet size) is a fixed length of 18 bytes (=144 bits). On the other hand, the size of a general-purpose data TLV packet (general-purpose data TLV packet size) is not a fixed length.

The remultiplexer 20 includes an LLch packet generator 21 . The LLch packet generation unit 21 converts emergency data and general-purpose data into TLV/IP packets. The LLch packet generation unit 21 may be located within the remultiplexing device 20 installed in the broadcasting station or the base station, or may be located within the transmitting device 30 installed at each transmitting station.

FIG. 3 is a block diagram showing a configuration example of the LLch packet generation section 21. As shown in FIG. The LLch packet generation unit 21 shown in FIG. 3 includes an error detection and correction encoding unit 211, a TLV/IP packetization unit 212, a general-purpose data size storage unit 213, and a general-purpose data size acquisition unit 214.

The error detection and correction encoding unit 211 adds an error detection code or performs error correction encoding on general-purpose data indicating general-purpose information, and outputs the data to the TLV/IP packetization unit 212 . A CRC code may be used as the error detection code. The error correction code may be an error correction code defined algebraically on GF(2), such as a Hamming code or a BCH code, or may be used as an AL (Application Layer)-FEC.

The general-purpose data size storage unit 213 stores general-purpose data TLV packet sizes for each transmission parameter (frequency bandwidth mode, partial reception flag, FFT (Fast Fourier Transform) size, etc.). That is, the general-purpose data TLV packet size is determined based on transmission parameters.

FIG. 4 is a diagram showing an example of general-purpose data TLV packet size for each transmission parameter. The general-purpose data size storage unit 213 stores the correspondence between transmission parameters and general-purpose data TLV packet sizes (in bytes), as shown in FIG.

The general-purpose data size acquisition unit 214 grasps the transmission parameter from the control information, acquires the general-purpose data TLV packet size corresponding to the transmission parameter from the general-purpose data size storage unit 213, and outputs it to the TLV/IP packetization unit 212. . For example, if the transmission parameters are frequency bandwidth normal mode, partial reception band with partial reception, and FFT size 8k, according to FIG. 4, the general data TLV packet size is 85 bytes.

For emergency data, the TLV/IP packetization unit 212 outputs an emergency data TLV packet that is packetized into a 144-bit TLV packet, as in the conventional case. Furthermore, the TLV/IP packetization unit 212 divides the general-purpose data encoded by the error detection and correction encoding unit 211 into TLV/IP packet sizes that can be embedded in the surplus area of the LLch, and packetizes the general-purpose data. A general-purpose data TLV packet is output. At this time, the size of the general-purpose data TLV packet is determined based on the general-purpose data TLV packet size input from the general-purpose data size acquisition unit 214.

As a modification, the general-purpose data may be input to the transmitting device 30 instead of the remultiplexing device 20. In that case, the general-purpose data TLV packet is generated by the transmitting device 30 rather than the remultiplexing device 20 through similar processing.

(transmission device)
Next, a transmitting device 30 according to an embodiment of the present invention will be described. The transmitting device 30 is a device that transmits transmission data including emergency information and general-purpose information using LLch. The transmitter 30 modulates the TLV/IP packet input from the transmitter remultiplexer 20 to configure an OFDM frame, and transmits an OFDM signal via an antenna. The transmitter 30 may be configured with dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array), a processor, or a combination of both. It's okay.

FIG. 5 is a block diagram showing a configuration example of the transmitting device 30 when the number of layers is three. The transmitting device 30 shown in FIG. It includes a determining section 37, an LDPC encoding section 38, a combining section 39, an OFDM frame configuration section 40, and an OFDM modulation section 41. Furthermore, the layer processing section 32 includes an error correction encoding section 321, a bit interleaving section 322, and a mapping section 323.

The layer separation unit 31 receives TLV/IP packets from the remultiplexer 20, separates packets belonging to each layer, and distributes them to each layer processing unit 32. Further, the LLch packet is output to the information determining section 37. Furthermore, the layer separation section 31 outputs synchronization control information to the pilot signal generation section 35 and the TMCC signal generation section 36.

The error correction encoding unit 321 performs error correction encoding (for example, LDPC encoding) on the signal input from the layer separation unit 31 to generate an encoded signal, so that transmission errors can be corrected on the receiving side of the OFDM signal. do. Then, the error correction encoding section 321 outputs the generated encoded signal to the bit interleaving section 322.

In order to improve the performance of the error correction code, the bit interleaving unit 322 generates bit data by interleaving the encoded signal inputted from the error correction encoding unit 321 in units of bits. Then, the bit interleaving unit 322 outputs the generated bit data to the mapping unit 323.

The mapping section 323 maps the bit data input from the bit interleaving section 322 onto the IQ plane, and generates carrier symbols subjected to carrier modulation according to the modulation method. Then, the mapping section 323 outputs the generated carrier symbol to the hierarchical combining section 33.

The layer synthesis section 33 synthesizes the carrier symbols input from the mapping section 323 of each layer, and outputs the synthesized carrier symbols to the time/frequency interleaving section 34.

The time/frequency interleaving unit 34 rearranges the order of carrier symbols input from the hierarchical combining unit 33 in the time direction and frequency direction to generate an interleaved signal subjected to interleaving processing. Then, the time/frequency interleaving unit 34 outputs the generated interleaved signal to the OFDM frame configuration unit 40.

Pilot signal generation section 35 generates pilot signals (SP signal and CP signal) from the synchronization control information input from layer separation section 31 and outputs them to OFDM frame configuration section 40 .

The TMCC signal generation unit 36 generates a TMCC signal from the synchronization control information input from the layer separation unit 31 and outputs it to the OFDM frame configuration unit 40.

The information determining unit 37 determines whether the LLch packet input from the layer separating unit 31 is an emergency data TLV packet or a general data TLV packet by referring to the transmission data type signal included in the TLV packet. Then, the information determining unit 37 outputs the emergency data TLV packet to the LDPC encoding unit 38 and outputs the general data TLV packet to the combining unit 39.

Note that the transmitting device 30 may not include the information determination unit 37, but may allocate a dedicated ID to the general-purpose data TLV packet, and have the layer separation unit 31 separate the emergency data TLV packet and the general-purpose data TLV packet. .

The LDPC encoding unit 38 performs LDPC encoding on the emergency data TLV packet, generates an LDPC code of fixed length (as shown in FIG. 2, the code length is 1224 bits and the information length is 144 bits), and the combining unit Output to 39.

The combining unit 39 generates a combined packet by combining the general-purpose data TLV packet input from the information determining unit 37 after (for example, immediately after) the plurality of LDPC codes input from the LDPC encoding unit 38, and generates a combined packet by combining the general-purpose data TLV packet input from the information determining unit 37. Output to 40.

OFDM frame configuration section 40 inserts the pilot signal input from pilot signal generation section 35 and the TMCC signal input from TMCC signal generation section 36 into the interleaved signal input from time/frequency interleaving section 34 . Further, the OFDM frame configuration unit 40 allocates the combined packet input from the combination unit 39 to an LLch carrier that is a subcarrier for LLch, and modulates it using a predetermined modulation method (for example, DBPSK) to configure an OFDM frame. Then, the OFDM frame configuration section 40 outputs the generated OFDM frame to the OFDM modulation section 41.

The OFDM frame configuration unit 40 allocates the combined packet input from the combination unit 39 to an LLch carrier. More specifically, the OFDM frame configuration unit 40 assigns the LLch carrier symbol of the general-purpose data TLV packet to the surplus area when a plurality of LLch carrier symbols of the LDPC code of the emergency data TLV packet are allocated to the LLch carrier in one OFDM frame. assign.

OFDM modulation section 41 performs OFDM modulation processing on the OFDM frame input from OFDM frame configuration section 40 to generate an OFDM signal, and transmits the generated OFDM signal to receiving device 50 . More specifically, the OFDM modulation unit 41 performs IFFT (Inverse Fast Fourier Transform) processing on the OFDM symbols of the OFDM frame input from the OFDM frame configuration unit 40 to obtain a time domain effective symbol signal. generate. Then, the OFDM modulator 41 inserts a guard interval at the beginning of the effective symbol signal, and then performs orthogonal modulation processing and D/A conversion processing to generate an OFDM signal.

(Receiving device)
Next, a receiving device 50 according to an embodiment of the present invention will be described. The receiving device 50 is a device that receives transmission data including emergency information and general-purpose information using the LLch. Receiving device 50 receives an OFDM signal from transmitting device 30 via an antenna. The receiving device 50 may be configured with dedicated hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array), a processor, or a combination of both. It's okay.

FIG. 6 is a block diagram showing a configuration example of a receiving device when the number of layers is three. The receiving device shown in FIG. 6 includes an OFDM demodulation section 51, a pilot signal detection section 52, a propagation path estimation section 53, an equalization section 54, a time/frequency deinterleaving section 55, and a likelihood ratio calculation section 56. , a bit deinterleaving unit 57, an error correction decoding unit 58, an LLch demodulation unit 59, an information discrimination unit 60, an LDPC decoding unit 61, an error detection and correction decoding unit 62, and an output I/F 63.

The OFDM demodulation unit 51 receives the OFDM signal transmitted from the transmitting device 30, and performs OFDM demodulation processing on the received signal. More specifically, the OFDM demodulation section 51 performs A/D conversion processing and orthogonal demodulation processing on the received OFDM signal, removes guard intervals, and extracts effective symbol signals. Then, OFDM demodulation section 51 performs FFT (Fast Fourier Transform) processing on the effective symbol signal to generate a complex baseband signal, and outputs it to pilot signal detection section 52 . Further, OFDM demodulation section 51 outputs each layer data of the complex baseband signal to equalization section 54 and outputs the LLch carrier symbol to LLch demodulation section 59.

Pilot signal detection section 52 detects a pilot signal included in the complex baseband signal input from OFDM demodulation section 51 and outputs it to propagation path estimation section 53.

The propagation path estimation section 53 estimates a propagation path response based on the pilot signal input from the pilot signal detection section 52 and outputs the estimation result to the equalization section 54.

The equalization unit 54 uses the estimation result of the propagation path response to perform equalization processing to correct the propagation path distortion of the signal input from the OFDM demodulation unit 51 to reproduce carrier symbols, and the time/frequency deinterleaving unit 55 Output to.

The time/frequency deinterleaving unit 55 performs deinterleaving processing on the carrier symbols input from the equalization unit 54 in the time direction and the frequency direction, and outputs the result to the likelihood ratio calculation unit 56. This deinterleaving process is a process of returning data rearranged by the time/frequency interleaving unit 34 of the transmitting device 30 to its original order.

The likelihood ratio calculation unit 56 calculates the LLR (Log Likelihood Ratio) of each transmitted bit from the data input from the time/frequency deinterleaving unit 55 and outputs it to the bit deinterleaving unit 57. .

The bit deinterleaving unit 57 performs deinterleaving processing in the bit direction on the LLR corresponding to each bit input from the likelihood ratio calculation unit 56 to generate a bit deinterleaving signal. This deinterleaving process is a process of returning data rearranged by the bit interleaving unit 322 of the transmitting device 30 to its original order.

The error correction decoding unit 58 uses the LLR input from the bit deinterleaving unit 57 to decode the estimated value of the transmitted bit by a known method (for example, the sum-product decoding method).

The LLch demodulation section 59 generates a combined packet by demodulating the LLch carrier symbol using a predetermined modulation method (eg, DBPSK), and outputs the combined packet to the information determination section 60 . Here, the combined packet is a packet (general-purpose data) in which a plurality of LDPC codes (urgent data) obtained by LDPC encoding an emergency data TLV packet and a general-purpose data TLV packet are combined. Each LDPC code is of fixed length.

The information determining unit 60 extracts emergency data and general-purpose data from the combined packet input from the LLch demodulating unit 59 based on information indicating the position of the general-purpose data TLV packet.

FIG. 7 is a block diagram showing a configuration example of the information determining section 60. As shown in FIG. The information determination section 60 shown in FIG. 7 includes a switching section 601, a general-purpose data position storage section 602, and a general-purpose data position acquisition section 603.

The general-purpose data position storage unit 602 stores general-purpose data TLV packet positions for each transmission parameter (frequency bandwidth mode, partial reception flag, FFT size, etc.). That is, the general data TLV packet position is determined based on the transmission parameters.

FIG. 8 is a diagram showing an example of general-purpose data TLV packet positions for each transmission parameter. The general-purpose data position storage unit 602 stores the correspondence between transmission parameters and general-purpose data TLV packet positions as shown in FIG. When the general-purpose data TLV packet is combined immediately after the LDPC code of the emergency data TLV packet, the position of the general-purpose data TLV packet can be set to the number of LDPC codes of the emergency data TLV packet, as shown in FIG.

The general-purpose data position acquisition unit 603 grasps the transmission parameter from the control information, acquires the general-purpose data TLV packet position corresponding to the transmission parameter from the general-purpose data position storage unit 602, and outputs it to the switching unit 601. For example, when the transmission parameters are a frequency bandwidth normal mode, a partial reception band with partial reception, and an FFT size of 8k, the number of LDPC codes for emergency data is 6 according to FIG. 8 . As shown in Figure 2, if the size of the LDPC code of the emergency data TLV packet is 1224 bits, the LLch is arranged from the beginning in the OFDM frame, so up to 1224 x 6 bits are emergency data, and the next bit is general-purpose data. It turns out that it is data.

The switching unit 601 discriminates between emergency data and general-purpose data based on the general-purpose data TLV packet position input from the general-purpose data position acquisition unit 603, outputs the urgent data to the LDPC decoding unit 61, and performs error detection and correction on the general-purpose data. It is output to the decoding section 62. When the general-purpose data TLV packet position is the number of LDPC codes of the emergency data TLV packet, the switching unit 601 counts the number of input bits of the combined packet and discriminates between emergency data and general-purpose data.

The LDPC decoding unit 61 performs LDPC decoding on the emergency data input from the switching unit 601 to generate an emergency data TLV packet, and outputs it to the output I/F 63.

The error detection/correction decoding unit 62 performs error correction or error detection on the general-purpose data (binary data) input from the switching unit 601 and outputs it to the output I/F 63 . Note that if an error is detected, the error detection and correction decoding unit 62 discards the data and does not output it.

The output I/F 63 switches each layer data inputted from the error correction decoding unit 58, the emergency data TLV packet inputted from the LDPC decoding unit 61, and the general-purpose data TLV packet inputted from the error detection and correction decoding unit 62, and outputs the external data. Output to.

In this way, the distribution system 1 can transmit general-purpose information in addition to emergency information using the LLch. Furthermore, the transmitting device 30 performs LDPC encoding on the emergency data TLV packet, converts it into a fixed-length LDPC encoder, and combines the general-purpose data TLV packet with the plurality of LDPC codes, thereby improving the frequency usage efficiency in the distribution system 1. It becomes possible to do so. For example, it becomes possible to allocate the LLch carrier symbol of a general-purpose data TLV packet to a surplus area that has not been used in the past. Note that since the service uses gaps in the broadcasting service, the broadcasting service itself will not be affected.

(program)
In order to function as the above-described transmitting device 30 and receiving device 50, it is also possible to use a computer that can execute program instructions, respectively. Here, the computer may be a general-purpose computer, a dedicated computer, a workstation, a PC (Personal Computer), an electronic notepad, or the like. Program instructions may be program code, code segments, etc. to perform necessary tasks.

The computer includes a processor, a storage section, an input section, an output section, and a communication interface. Processors include CPUs (Central Processing Units), MPUs (Micro Processing Units), GPUs (Graphics Processing Units), DSPs (Digital Signal Processors), and SoCs (System on a Chip). may be configured. The processor controls each of the above components and performs various calculation processes by reading and executing programs from the storage unit. Note that at least a part of these processing contents may be realized by hardware.

The program may be recorded on a computer readable recording medium. Using such a recording medium, it is possible to install a program on a computer. Here, the recording medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a CD-ROM, a DVD-ROM, a USB (Universal Serial Bus) memory, or the like. Further, this program may be downloaded from an external device via a network.

For example, a program for functioning as the transmitting device 30 includes the steps of performing LDPC encoding on an emergency data TLV packet to generate a fixed-length LDPC code, and combining a plurality of LDPC codes with a packet containing general-purpose information. A computer is caused to execute the steps of generating a packet and allocating the combined packet to an LLch carrier.

For example, a program for functioning as the receiving device 50 combines a plurality of LDPC codes obtained by LDPC-encoding an emergency data TLV packet and a general-purpose data TLV packet by demodulating LLch carrier symbols using a predetermined modulation method. The computer executes the following steps: generating a combined packet based on the combined packet; extracting an LDPC code and general-purpose data TLV packet from the combined packet; and performing LDPC decoding on the LDPC code.

Furthermore, the above-described transmitting device 30 and receiving device 50 may each be configured with one or more semiconductor chips. This semiconductor chip may be equipped with a CPU that executes a program that describes processing contents for realizing each function of the transmitting device 30 and the receiving device 50.

Although the embodiments described above have been described as representative 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 invention. Therefore, the present invention should not be construed as being limited to 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 integrate a plurality of configuration blocks described in the configuration diagram of the embodiment, or to divide one configuration block.

1 Distribution system 10 Multiplexing device 20 Re-multiplexing device 21 LLch packet generation section 30 Transmission device 31 Layer separation section 32 Layer processing section 33 Layer synthesis section 34 Time/frequency interleaving section 35 Pilot signal generation section 36 TMCC signal generation section 37 Information Discrimination unit 38 LDPC encoding unit 39 Combining unit 40 OFDM frame configuration unit 41 OFDM modulation unit 50 Receiving device 51 OFDM demodulation unit 52 Pilot signal detection unit 53 Channel estimation unit 54 Equalization unit 55 Time/frequency deinterleaving unit 56 Likelihood Ratio calculation unit 57 Bit deinterleaving unit 58 Error correction decoding unit 59 LLch demodulation unit 60 Information discrimination unit 61 LDPC decoding unit 62 Error detection and correction decoding unit 63 Output I/F
211 Error detection and correction encoding unit 212 TLV/IP packetization unit 213 General-purpose data size storage unit 214 General-purpose data size acquisition unit 321 Error correction encoding unit 322 Bit interleaving unit 323 Mapping unit 601 Switching unit 602 General-purpose data position storage unit 603 General-purpose Data position acquisition part

Claims (8)

A transmitting device that transmits transmission data using LLch,
The transmitted data includes emergency information and general information,
an LDPC encoding unit that performs LDPC encoding on the packet containing the emergency information to generate a fixed-length LDPC code;
a combining unit that generates a combined packet in which a plurality of the LDPC codes and a packet containing the general-purpose information are combined;
an OFDM frame configuration unit that allocates the combined packet to an LLch carrier that is a subcarrier for LLch;
A transmitting device comprising: According to claim 1, the OFDM frame configuration unit allocates the LLch carrier symbol of the packet containing the general-purpose information to a surplus area when a plurality of LLch carrier symbols of the LDPC code are allocated to the LLch carrier in one OFDM frame. Transmitting device as described. The transmitting device according to claim 2, wherein the size of the packet containing the general-purpose information is determined based on transmission parameters. A receiving device that receives transmission data using LLch,
The transmitted data includes emergency information and general-purpose information,
an LLch demodulator that generates a combined packet in which a plurality of LDPC codes obtained by LDPC encoding the packet containing the emergency information and the packet containing the general-purpose information are combined by demodulating the LLch carrier symbol using a predetermined modulation method; and,
an information determining unit that extracts a packet including the LDPC code and the general-purpose information from the combined packet;
an LDPC decoding unit that performs LDPC decoding on the LDPC code;
A receiving device comprising: The receiving device according to claim 4, wherein the information determining unit determines the LDPC code and the general-purpose information based on the number of LDPC codes of the packet containing the emergency information. The receiving device according to claim 5, wherein the number of LDPC codes of the packet containing the emergency information is determined based on transmission parameters. A program for causing a computer to function as the transmitting device according to any one of claims 1 to 3. A program for causing a computer to function as the receiving device according to claim 4.

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