JP7307613B2 - Transmission server, transmission device, reception device and program - Google Patents

Description

TECHNICAL FIELD The present invention relates to the technical fields of satellite broadcasting, terrestrial broadcasting, fixed communication and mobile communication, and in particular, a transmission server, a transmission device and a reception device relating to digital broadcasting that enable data transmission by linking broadcasting and communication. , as well as programs.

In digital transmission systems for satellite broadcasting and terrestrial broadcasting, a multilevel modulation system is often used so that more information can be transmitted in the frequency bandwidth available for each service. In order to increase the frequency utilization efficiency, it is effective to increase the number of bits (modulation order) assigned to one symbol of the modulated signal. Limited by the Shannon limit. Satellite digital broadcasting is an example of a form of information transmission using a satellite transmission line.

In digital broadcasting systems for satellite broadcasting and terrestrial broadcasting, an error correction code is used as a technique for improving transmission performance under white noise. For example, in satellite digital broadcasting currently in use, information correction is performed in a receiver using an error correction code. By adding a redundant signal called a parity bit to the information to be sent, it is possible to control the signal redundancy (encoding rate) and improve resistance to noise.

Error correction codes and modulation schemes are closely related, and the theoretical upper limit of frequency utilization efficiency with respect to the signal-to-noise ratio is called the Shannon limit. LDPC (Low Density Parity Check) code was proposed by Gallagher in 1962 as one of the powerful error correction codes having performance approaching the Shannon limit (see, for example, Non-Patent Document 1).

ARIB STD-B44 (hereinafter referred to as "advanced satellite broadcasting system"), which defines the transmission system for 4K/8K Super Hi-Vision satellite broadcasting, which is the next-generation broadcasting service, specifies the utilization efficiency of the signal-to-noise ratio. An LDPC (Low Density Parity Check) code, which is a powerful error correction code having performance approaching the theoretical upper limit of the Shannon limit, is used (see, for example, Non-Patent Document 2).

An LDPC code is a linear code defined by a very sparse parity check matrix H (parity check matrix elements consist of 0s and 1s and the number of 1s is very small).

The LDPC code is a powerful error-correcting code that can obtain transmission characteristics approaching the Shannon limit by increasing the code length and using an appropriate parity check matrix. LDPC codes are also adopted in ARIB STD-B44 (hereinafter referred to as an advanced satellite broadcasting system; see Non-Patent Document 2, for example), which defines the transmission system of . Combining multilevel modulation with powerful error correction codes such as LDPC codes has enabled transmission with higher frequency utilization efficiency.

Taking the advanced satellite broadcasting system as an example, the code length of the LDPC code in this system is composed of Forward Error Correction (FEC) frames and is 44880 bits. It has been shown that the performance is within about 1 dB from the theoretical upper limit of the frequency utilization efficiency with respect to the signal-to-noise ratio when .

In the advanced satellite broadcasting system, the LDPC coding rate is 41/120 (≈ 1/3), 49/120 (≈ 2/5), 61/120 (≈ 1/2), 73/120 (≈ 3/5), 81/120 (≈ 2/3), 89/120 (≈ 3/4), 93/120 (≈ 7/9), 97/120 (≈ 4/5), 101/120 (≈ 5/6), 105/120 (≈7/8), and 109/120 (≈9/10).

Furthermore, in recent years, in addition to the current 2K broadcasting service by satellite/terrestrial broadcasting and 4K/8K Super Hi-Vision by satellite broadcasting, the provision of 4K/8K Super Hi-Vision by terrestrial broadcasting is expected.

Here, focusing on the 12 GHz band used for satellite broadcasting, the available frequencies are tight, and the frequency bandwidth is sufficient for the transmission of next-generation content that exceeds the transmission capacity of 4K/8K high-definition services. It is difficult to secure Under such circumstances, the 21 GHz band distributed to Japan as a frequency band for satellite broadcasting (BSS) by ITU-R is attracting attention. Since this frequency band has a wide band of 600 MHz, AR (Augmented Reality) can be considered as a next-generation content transmission service that exceeds the transmission capacity of 4K/8K high-definition services, as well as 2K or 4K/8K Super Hi-Vision. ), VR (Virtual Reality), stereoscopic television, and other large-capacity transmission applications.

However, in digital satellite broadcasting, the transmission conditions deteriorate due to rainfall, and in digital terrestrial broadcasting, fading. In particular, in the case of transmission in the 21 GHz band, it is assumed that the effect of rainfall attenuation will be about three times as large as the dB value in the 12 GHz band.

On the other hand, recently, it has become possible to provide a service that links broadcasting and communication, such as transmitting a broadcast program from a transmitting side to a receiving device via an IP (Internet Protocol) network.

However, a general IP network is assumed to be an erasure channel (PEC: Packet Erasure Channel) in which information is lost due to some failure such as line congestion.

R. G. Gallager, “Low-Density Parity-Check Codes,” in Research Monograph series Cambridge, MIT Press, December 1963. "Transmission system for advanced wideband satellite digital broadcasting (ISDB-S3) Standard ARIB STD-B44 Version 2.1", [online], revised on March 25, 2016, ARIB, [searched on June 12, 2001] , Internet <URL: https://www.arib.or.jp/kikaku/kikaku_hoso/std-b44.html> Suzuki et al., “Design of LDPC Code for Advanced BS Digital Broadcasting”, Journal of The Institute of Image Information and Television Engineers, Institute of Image Information and Television Engineers, Image Information Media vol.62, No.12, December 1, 2008, pp.1997 -2004

As mentioned above, in recent years, not only 2K or 4K/8K Super Hi-Vision, but also large-capacity AR, VR, 3D TV, etc., are considered as next-generation content transmission services that exceed the transmission capacity of 4K/8K high-definition services. Transmission services are expected.

On the other hand, satellite digital broadcasting suffers from attenuation due to rainfall, terrestrial digital broadcasting suffers from fading, and digital broadcasting suffers from the problem that transmission conditions deteriorate to such an extent that the signal cannot be recovered only by error correction codes.

Therefore, there is a demand for a technique that enables large-capacity transmission services for broadcast programs and compensates for poor reception due to deterioration of transmission conditions related to broadcast transmission lines.

Therefore, it is conceivable to apply a technique for linking broadcasting and communication, such as transmitting a broadcast program from the transmitting side to a receiving device via an IP network. It is necessary to adopt a technique that takes into consideration that it is a path (PEC).

In particular, in future satellite broadcasting, based on the scarcity of frequencies for satellite broadcasting in the 12 GHz band, the transmission equipment will use the broadcasting transmission line of the 21 GHz band satellite frequency that enables large-capacity transmission, and will adopt an advanced satellite broadcasting system. The transmission data of the broadcast program is transmitted to the receiving device in a highly resistant manner to white noise using an error correction code (LDPC code) that is processed in an error correction frame with a constant code length like is assumed. In this case, in order to use IP transmission to compensate for poor reception on the receiving side due to rain attenuation on the broadcast transmission line, it is necessary to establish a high affinity between broadcasting and IP transmission, and to use IP packets generated in the IP network. A transmission server is desired that transmits the transmission data of the broadcast program to the receiving device using the IP network so as to compensate for the loss of the broadcast program. In addition, the receiver needs to be devised to accurately restore the broadcast program based on the data received via the broadcast transmission line and IP network.

Therefore, in view of the above-mentioned problems, the object of the present invention is to enable large-capacity transmission of broadcast programs by linking broadcasting and communication in a highly compatible manner, and to prevent deterioration of transmission conditions related to broadcast transmission lines. It is an object of the present invention to provide a transmission server, a transmission device and a reception device relating to digital broadcasting, and a program, which enable data transmission by compensating for poor reception on the receiving side and packet loss on an IP network.

Further, the transmission server of the present invention is a transmission server that receives transmission data of a broadcast program in the form of variable-length packets, transforms them into IP packets, and transmits the IP packets to a receiving device. Store transmission data of broadcast programs in the form of variable-length packets in the order of input, add a sequence header indicating the packet order to the head of each variable-length packet, and rearrange a predetermined number of variable-length packets in the order of input. and a variable-length packet sorting means for regularly rearranging variable-length packets, and among the predetermined number of variable-length packets after regular rearrangement, transmission/reception of variable-length packets of packet lengths that have vacancies when the longest packet length is used as a reference. stuffing bit adding means for adding stuffing bits having a known pattern between them ; and stuffing bit adding means for adding stuffing bits having a known pattern between them; Error-correcting frames, including headers, based on the same coding method as the error-correcting coding method processed by error-correcting frames with a constant code length used in the transmitting device, and at a coding rate independent of the transmitting device. and error correction encoding means for performing error correction encoding processing, and removing the stuffing bits after the error correction encoding processing, and adding the variable length packet including the sequence header and the error correction encoding processing. stuffing bit removing means for extracting the information of the parity bit area obtained in the length direction of the variable -length packet; IP packet generation means for sequentially converting information into IP packets and transmitting the information to a receiving device capable of receiving transmission data from the transmitting device via an IP network.

Further, in the transmission server of the present invention, the variable-length packet sorting means sorts the predetermined number of variable-length packets in the order of input so that addition of the stuffing bit can be predicted by the receiving device. It is characterized in that it is performed in descending order or ascending order based on.

Further, in the transmission server of the present invention, the error correction encoding method used in the transmission device includes an LDPC code, the error correction encoding means is based on the same processing as the LDPC code, and is different from the transmission device It is characterized in that an error correction frame is formed with independent coding rates and error correction coding is performed.

Furthermore, a transmission device of the present invention is a transmission device relating to digital broadcasting, and is characterized by including the transmission server of the present invention inside the device.

Further, the receiving apparatus of the present invention receives IP packets related to the broadcast program from the transmission server of the present invention via the IP network, refers to the sequence header, and retrieves the error correction frame used by the transmission server. IP packet receiving means for sequentially extracting a predetermined number of IP packets for reconstruction, and the sequence header, variable length packets, and parity bits as encoded data sequentially stored from the predetermined number of IP packets. stuffing bit addition means for extracting information, predicting and adding stuffing bits used in the transmission server from the regularity of arrangement of each variable-length packet, and encoding to which the stuffing bits are added After reconstructing the error correction frame used in the transmission server for the data, performing likelihood determination, performing decoding processing according to the coding rate corresponding to the error correction encoding processing in the transmission server, and performing error correction decoding a stuffing bit removing means for removing the stuffing bits from the error-correction-decoded data to extract an error-corrected variable-length packet; and referring to the sequence header. Then, the regular rearrangement by the transmission server is reversed, rearranged so as to restore the variable-length packets of the transmission data, and the sequence header added to each variable-length packet is deleted to extract the received data. Variable-length packet sorting means, reception data obtained by broadcast reception obtained from the transmitting device via a broadcast transmission line, and reception data via an IP network obtained from the variable-length packet sorting means can be switched or synthesized and reproduced. receiving data switching/synthesizing means for outputting to the outside.

Further, in the receiving device of the present invention, the error correction decoding means is a predetermined type that is used in common with decoding processing of an error correction coding system related to broadcast reception obtained from the transmitting device via a broadcast transmission line. The decoding process is performed according to the coding rate by referring to the parity check matrix table corresponding to the coding rate.

Also, the program of the present invention constitutes a program for causing a computer to function as the transmission server of the present invention.

Moreover, the program of the present invention constitutes a program for causing a computer to function as the receiving device of the present invention.

According to the present invention, it is possible to transmit a large amount of broadcast programs by linking broadcasting and IP transmission in a highly compatible manner. Data can be transmitted by compensating for packet loss.

1 is a block diagram showing a schematic configuration of a transmission system including a transmission server, a transmission device and a reception device according to one embodiment of the present invention; FIG. 1 is a block diagram showing a schematic configuration of a transmission server and a transmission device according to one embodiment of the present invention; FIG. 1 is a block diagram showing a schematic configuration of a receiver according to one embodiment of the present invention; FIG. 1 is a block diagram showing a schematic configuration of a transmission system including a transmission server, a transmission device and a reception device for advanced wideband satellite digital broadcasting of 21 GHz band satellite frequency according to one embodiment of the present invention; FIG. 4(a) and 4(b) are explanatory diagrams of processing of a variable-length packet sorting unit and a stuffing bit adding unit, respectively, in the transmission server according to one embodiment of the present invention; FIG. 4(a) and 4(b) are explanatory diagrams of each process of an error correction encoder, a stuffing bit remover, and an IP packet generator in the transmission server of one embodiment according to the present invention, respectively; FIG. 4(a) and 4(b) are explanatory diagrams of respective processes of an IP packet receiving section, a stuffing bit adding section, and an error correction decoding section in the receiving apparatus according to one embodiment of the present invention; FIG. 4(a) and 4(b) are explanatory diagrams of respective processes of a stuffing bit removing section and a variable length packet sorting section in the receiving apparatus according to one embodiment of the present invention; FIG.

[Transmission system]
FIG. 1 is a block diagram showing a schematic configuration of a transmission system 1 including a transmission server 6, transmission devices 2 and 3, and a reception device 5 according to one embodiment of the present invention. A transmission system 1 shown in FIG.

The transmission device 2 generates encoded data by applying an error correction encoding process to the transmission data of the broadcast program using an error correction frame having a constant code length and adding an error correction code parity. This device digitally modulates converted data by a predetermined modulation method to generate a modulated wave signal, and radiates radio waves related to digital broadcasting via a satellite broadcasting transmission line including a broadcasting satellite 4 via a transmitting antenna 2a. For example, the transmitting device 2 may be a transmitting device for advanced wideband satellite digital broadcasting operating on the 21 GHz band satellite frequency.

The transmission device 3 generates encoded data by applying an error correction encoding process to the transmission data of the broadcast program using an error correction frame having a constant code length and adding an error correction code parity. This device digitally modulates converted data by a predetermined modulation method to generate a modulated wave signal, and radiates radio waves related to digital broadcasting via a terrestrial broadcasting transmission line via a transmitting antenna 3a. For example, the transmission device 3 can be a transmission device for next-generation digital terrestrial broadcasting that uses error correction coding processing in error correction frames with a fixed code length.

The transmission data of the broadcast program input to the transmission device 2 is input as fixed-length TS packets in the broadcast TS (Transport Stream), variable-length TS packets, TLV (Type-Length-Value) It is input in the form of variable-length packets such as packets, MMTP (MPEG Media Transport Protocol) packets based on MPEG2-TS, and IP packets. However, since the variable-length packet may have a fixed length, the transmission device 2 is configured so that transmission data can be input in the form of a variable-length packet.

The transmission server 6 adds a sequence header indicating the packet order to the transmission data (variable length packet) of the same broadcast program as that transmitted from the transmission device 2 (or the transmission device 3), and encodes the error correction coding code. By regularly rearranging a predetermined number of variable-length packets that depend on the conversion rate, stuffing bits consisting of a known pattern between transmission and reception (between transmission device 2 (or transmission device 3) and reception device 5) is predictable on the receiving device 5 side, based on the same encoding method as the error correction encoding method used in the transmitting device 2 (or transmitting device 3) in the direction orthogonal to the length direction of the variable-length packet , and the function of performing error correction coding processing at a coding rate independent of the transmission device 2 (or transmission device 3) related to broadcasting, and the function of removing the stuffing bit and changing the information after the error correction coding The computer has a function of sequentially converting long packets into IP packets in the length direction and transmitting the IP packets to the receiving device 5 via the IP network 8 .

The receiving device 5 receives and demodulates the modulated wave signal radiated from the transmitting device 2 via the receiving antenna 5a, reconstructs the error correction frame constituting the code length of the error correction code, and corrects the error in the transmitting device 2. A function to generate and reproduce reception data by performing decoding processing corresponding to the correction encoding processing, and a function to receive and demodulate a modulated wave signal emitted from the transmission device 3 via the reception antenna 5b and demodulate it. This device has a function of reconstructing an error correction frame constituting the code length of a correction code, performing decoding processing corresponding to the error correction coding processing in the transmission device 3, and generating reception data.

In addition to receiving the broadcast from the transmission device 2 (or the transmission device 3), the reception device 5 receives IP packets related to the broadcast program from the transmission server 6 via the IP network 8, and constructs an error correction frame. Extract the sequence header, variable-length packets, and parity bit information as stored encoded data sequentially from a predetermined number of IP packets for , a function of predicting and adding stuffing bits consisting of a known pattern between the transmission server 6 side and the corresponding transmission and reception, a function of performing error correction decoding corresponding to the error correction encoding in the transmission server 6, and a receiving side after error correction decoding A function of removing the stuffing bits added in , and reordering the regular sorting by the transmission server 6 based on the information of the sequence header, and extracting the received data from the variable- length packet after the sorting. It has a function of switching between data received by broadcast reception and data received via the IP network 8, or synthesizing the data and outputting the data externally in a reproducible manner.

Although the transmission system 1 illustrated in FIG. 1 has been described as including the transmission device 2 and the transmission device 3, only one of the transmission device 2 and the transmission device 3 may be provided. Also, in the transmission system 1 illustrated in FIG. may be

Hereinafter, more specifically, the transmitting device 2 (or transmitting device 3), the transmitting server 6, and the receiving device 5 will be described in order.

[Transmitter]
FIG. 2 is a block diagram showing a schematic configuration of the transmission server 6 and transmission device 2 (or transmission device 3) of one embodiment according to the present invention. It should be noted that the transmitting device 2 (or transmitting device 3) shown in FIG. 2 shows only main components related to the present invention, and description of other components such as energy diffusion processing is omitted.

The transmission device 2 and the transmission device 3 employ an error correction coding process and a modulation method suitable for each broadcasting transmission line (satellite broadcasting transmission line or terrestrial broadcasting transmission line). A comprehensive description will be given assuming that the correction coding unit 21 and the modulation unit 22 are provided.

The error correction coding unit 21 generates coded data by performing error correction coding processing in which error correction frames having a constant code length are used for transmission data of a broadcast program and adding error correction code parity. , is an encoder that outputs to the modulation unit 22 . Here, the error correction coding process can be any process as long as it is an error correction frame with a constant code length, but is preferably specified by the advanced wideband satellite digital broadcasting transmission system (ISDB-S3). , a concatenated code of an LDPC code as an inner code and a BCH code as an outer code is used, and a predetermined type of LDPC coding rate can be set.

The modulation unit 22 digitally modulates the encoded data obtained from the error correction encoding unit 21 using a predetermined modulation method to generate a modulated wave signal, and radiates radio waves related to digital broadcasting via a broadcasting transmission line.

Transmission data of broadcast programs can be input to the transmission device 2 (or transmission device 3) in the form of variable-length packets, as described above. MMTP packets based on MPEG2-TS described in B31 and used in terrestrial digital broadcasting, and TLV packets described in ARIB STD-B44 and used in advanced broadband satellite digital broadcasting when transmitted via satellite broadcasting transmission lines or in the form of MMTP packets or IP packets.

[Outgoing server]
The transmission server 6 shown in FIG. 2 includes a variable-length packet sorting unit 61 , a stuffing bit adding unit 62 , an error correction coding unit 63 , a stuffing bit removing unit 64 and an IP packet generating unit 65 .

The variable-length packet sorting unit 61 accumulates transmission data of the same broadcast program as that transmitted from the transmission device 2 (or transmission device 3) in the form of variable-length packets in the order of input, and puts a packet at the head of each variable-length packet. By adding a sequence header indicating the order and determining the number of packets to be arranged corresponding to the coding rate of the error correction coding in the error correction coding unit 63 in the subsequent stage, a predetermined number of packets depending on the coding rate of the error correction coding number of variable-length packets in input order.

The sequence header added to each variable-length packet includes at least a sequence number indicating the input order of each variable-length packet in the transmission data of the broadcast program, preferably information on the coding rate of error correction coding, and information identifying which broadcast program the packet is a variable length packet. Here, the information about the coding rate of error correction coding and the information identifying which broadcast program the variable-length packet belongs to may be omitted if they are predetermined between transmission and reception. From the sequence number, it is possible to identify which variable length packet is the transmission data of the broadcast program.

Then, the variable-length packet sorting unit 61 regularly sorts the predetermined number of variable-length packets in the input order (for example, sorts the variable-length packets in descending order or ascending order based on the packet length), and sequentially sorts the variable length packets. , to the stuffing bit adding unit 62 . In addition, when there are a plurality of variable-length packets of the same packet length, the variable-length packet sorting unit 61 arranges them in a predetermined order between transmission and reception, which is chronologically leading (or trailing). change.

The stuffing bit adding unit 62 applies a known pattern between transmission and reception to variable -length packets of packet lengths that have vacancies when the longest packet length is used as a reference among the predetermined number of variable-length packets after regular rearrangement. (bits of all “0” or “1” or a regular bit pattern of “0” and “1”) are added and output to the error correction coding unit 63 .

The error correction coding unit 63 encodes the predetermined number of variable-length packets to which the stuffing bits are added, in a direction orthogonal to the length direction of the variable-length packets, including the sequence header. Based on the same encoding method as the error correction encoding method used in the error correction encoding unit 21 in 3), the error correction frame is generated at an encoding rate independent of the transmission device 2 (or transmission device 3) related to broadcasting. Then, error correction coding processing is performed (that is, parity bits for error correction coding are added in accordance with the coding rate), and output to stuffing bit removal section 64 .

The stuffing bit removing unit 64 removes the stuffing bits added by the stuffing bit adding unit 62 after the error correction coding processing, and removes the variable length packet including the sequence header and the parity added by the processing of the error correction coding unit 63. The information of the bit area is extracted in the length direction of the variable-length packet and output to the IP packet generator 65 .

The IP packet generator 65 transmits the variable-length packet including the extracted sequence header in the length direction to the variable-length receiver 5 . When handling TLV packets or MMTP packets as variable-length packets, individual TLV packets or MMTP packets can be stored in one IP packet. Also, TLV packets can be stored in a form in which an MMTP packet header is added within one IP packet.

[Receiving device]
FIG. 3 is a block diagram showing a schematic configuration of the receiver 5 of one embodiment according to the present invention. The receiving device 5 includes a demodulation unit 51, an error correction decoding unit 52, a check matrix table storage unit 53, an IP packet reception unit 54, a stuffing bit addition unit 55, an error correction decoding unit 56, a stuffing bit removal unit 57, A variable-length packet sorting unit 58 and a received data switching/synthesizing unit 59 are provided.

The demodulator 51 receives and demodulates the modulated wave signal radiated from the transmitting device 2 (or the transmitting device 3) via the broadcasting transmission line (satellite broadcasting transmission line or terrestrial broadcasting transmission line), and obtains The resulting encoded data is output to the error correction decoding unit 52 .

The error correction decoding unit 52 reconstructs an error correction frame corresponding to the error correction encoding unit 21 on the transmission device 2 (or transmission device 3) side of the encoded data obtained from the demodulation unit 51, and converts the LLR (Log-likelihood ratio; logarithmic likelihood ratio), performs likelihood determination of each bit “0” and “1”, refers to parity check matrix table storage unit 53, and performs error correction coding processing in transmission device 2 (or transmission device 3) Decoding processing based on a parity check matrix table corresponding to the coding rate corresponding to .

The parity check matrix table storage unit 53 stores a parity check matrix table indicating linear code decoding information according to the coding rate of the error correction code. The error correction decoding unit 52 and the error correction decoding unit 56, which will be described later, may have different coding rates, but this parity check matrix table is shared and used as one corresponding to a predetermined type of coding rate. , thereby improving the efficiency of implementation. For example, when using an LDPC code as a common error correction code for the error correction decoding units 52 and 56, the error correction decoding unit 52 and the error correction decoding unit 56 described later share a parity check matrix table corresponding to the coding rate. can be used as

The IP packet receiving unit 54 receives IP packets related to the broadcast program from the transmission server 6 via the IP network 8, accumulates them in the order of the packet sequence number based on the header information of the IP packets, and stores the IP packets described in the sequence header. A predetermined number of IP packets for reconstructing the error correction frame used in the transmission server 6 are sequentially extracted by referring to the sequence number, and output to the stuffing bit addition unit 55 . Here, the IP packet receiver 54 allows some IP packets to be lost in the IP network 8 . From the sequence number, it is possible to identify which variable length packet is the transmission data of the broadcast program.

The stuffing bit addition unit 55 sequentially extracts the sequence header, the variable-length packet, and the parity bit information as the stored encoded data from the predetermined number of IP packets, and extracts the sequence of each variable-length packet. (As described above, on the transmission server 6 side, for example, the sequence of variable-length packets has regularity in descending or ascending order based on the packet length), the stuffing bits used in the transmission server 6 are predicted. , and output to the error correction decoding unit 56 . Here, the stuffing bit adding unit 55 predicts and adds the stuffing bits including the lost IP packet.

The error correction decoding unit 56 reconstructs the error correction frame used in the transmission server 6 for the encoded data to which the stuffing bit is added by the stuffing bit addition unit 55, and converts each bit "0" based on the LLR. and "1" likelihood determination, refer to the parity check matrix table storage unit 53, perform decoding processing based on the parity check matrix table according to the coding rate corresponding to the error correction encoding processing in the transmission server 6, and The corrected and decoded data is generated and output to the stuffing bit removal unit 57 .

The stuffing bit removing unit 57 removes the stuffing bits added by the stuffing bit adding unit 55 from the data after error correction decoding, extracts the variable length packets after error correction, and the variable length packet sorting unit 58 extracts the error corrected variable length packets. output to

Based on the sequence number described in the sequence header added to each variable-length packet, the variable-length packet sorting unit 58 restores the regular sorting performed by the variable-length packet sorting unit 61 on the transmission server 6 side and transmits the packets. It rearranges the data so as to restore the variable-length packets, deletes the sequence header added to each variable-length packet, extracts the received data, and outputs it to the received data switching/combining unit 59 . In addition, when there are a plurality of variable-length packets of the same packet length, the variable-length packet sorting unit 58 arranges them in a predetermined order between transmission and reception, which is chronologically leading (or trailing). change.

The received data switching/synthesizing unit 59 switches or synthesizes the received data obtained from the error correction decoding unit 52 via the broadcast transmission line by the broadcast reception and the received data via the IP network 8 obtained from the variable-length packet sorting unit 58. and output it externally so that it can be played back. For example, the received data switching/synthesizing unit 59 mainly outputs the received data obtained by receiving the broadcast, and when the reception quality related to the broadcast reception (for example, the reception quality based on the modulation error ratio) is equal to or less than a predetermined value, the IP It is possible to switch to data received via the network 8 or to switch according to user designation of the receiving device 5 . Furthermore, the received data switching/combining unit 59 uses the likelihood determination after the processing of the error correction decoding unit 52 and the likelihood determination after the processing of the error correction decoding unit 56, etc. Each posterior likelihood value (or evaluation value ), and based on the comparison of each posterior likelihood value (or evaluation value), bits with low likelihood in the data received by broadcast reception are converted to the likelihood in the data received via the IP network 8. It is possible to synthesize by replacing bits with high values.

<Example>
A more specific embodiment in which the transmission system 1 is configured for advanced wideband satellite digital broadcasting operating on the 21 GHz band satellite frequency will be described below.

FIG. 4 is a block diagram showing a schematic configuration of a transmission system 1 including a transmission server 6, a transmission device 2 and a reception device 5 according to one embodiment of the present invention. The same reference numerals are given to the same constituent elements for explanation.

In the transmission system 1 of one embodiment shown in FIG. 4, the transmission device 2 is an embodiment in which advanced wideband satellite digital broadcasting described in ARIB STD-B44 is taken as an example. On the other hand, the transmission server 6 in the present embodiment may be a concatenated code of LDPC code and BCH code, but from the viewpoint of transmission efficiency and reduction of processing related to error correction, LDPC described in ARIB STD-B44 Only the code is used as the error correction encoding process.

That is, the transmitting apparatus 2 shown in FIG. 4 uses a concatenated code of an LDPC code as an inner code and a BCH code as an outer code, and uses a predetermined type of LDPC coding rate described in ARIB STD-B44. shall be configurable.

The error correction frame described in ARIB STD-B44 is treated as a fixed slot with a code length of 44880 bits, and the transmitting device 2, when the LDPC coding rate is 61/120 (≈ 1/2), slot header: 176 bits (fixed), transmission data allocation length: 22440 bits (variable according to LDPC coding rate), BCH code parity length: 192 bits (fixed), stuff bit: 6 bits (fixed), and LDPC code parity Length: 22066 bits (variable according to the coding rate of LDPC).

On the other hand, the transmission server 6 shown in FIG. 4 uses only the LDPC code for the error correction coding process, but can set a predetermined type of LDPC coding rate described in ARIB STD-B44.

In other words, the transmission server 6 also transmits all bits except the LDPC code parity length when setting the LDPC coding rate in the same manner as in advanced wideband satellite digital broadcasting with a fixed error correction frame with a code length of 44880 bits. It can be the information length used for data allocation, ie, for example, when the LDPC coding rate is 61/120, the information length is 22814 bits. Since the code length is fixed at 44880 bits in both the transmission device 2 and the transmission server 6, the allocation length of transmission data and the LDPC code parity length are naturally determined when the LDPC coding rate is determined.

Therefore, the transmission device 2 illustrated in FIG. 4 is configured in the same manner as in FIG. 2 described above, and uses LDPC code and BCH code processing for transmission data of a broadcast program with a code length of 44880 bits and a constant error correction frame. Error-correcting coding processing using a concatenated code is performed to generate coded data, and the coded data is digitally modulated by a predetermined modulation method to generate a modulated wave signal, which is transmitted to a broadcasting satellite 4 via a transmitting antenna 2a. Radio waves related to digital broadcasting are emitted via satellite broadcasting transmission lines including

The transmission server 6 illustrated in FIG. 4 is configured in the same manner as in FIG. By regularly rearranging a predetermined number of variable-length packets that depend on the coding rate of correction coding, stuffing bits having a pattern known between transmission and reception can be predicted and added on the receiving device 5 side. Then, the transmission server 6 performs error correction coding (LDPC coding) processing in a direction orthogonal to the length direction of the variable-length packet at a coding rate independent of the transmission device 2 related to broadcasting, and the stuffing bit is removed, and the information after the error correction coding is converted into IP packets sequentially in the length direction of the variable-length packet and transmitted to the receiver 5 via the IP network 8 .

The receiving device 5 illustrated in FIG. 4 is configured in the same manner as in FIG. 3 described above, receives and demodulates the modulated wave signal emitted from the transmitting device 2 via the receiving antenna 5a, and determines the code length of the error correction code. is reconstructed, and decoding processing corresponding to the error correction encoding processing in the transmitting device 2 is performed to generate reception data.

In addition to receiving the broadcast from the transmission device 2, the reception device 5 illustrated in FIG. The sequence header, variable length packets, and parity bit information are extracted as stored encoded data sequentially from a predetermined number of IP packets. Then, the receiving device 5 predicts and adds stuffing bits having a known pattern between the transmission server 6 side and the corresponding transmission/reception based on the regularity of arrangement of each variable-length packet, and performs error correction coding in the transmission server 6. Perform error correction decoding corresponding to Finally, the receiving device 5 removes the stuffing bits added by the receiving side after the error correction decoding, restores the regular rearrangement by the transmission server 6 based on the sequence header information, and restores the sequence header. Received data is extracted from the variable-length packets after the deletion and rearrangement, and the data received by broadcast reception and the data received via the IP network 8 are switched or combined, and output to the outside in a reproducible manner.

(Operation of transmission server 6)
Hereinafter, specific operations of the transmission server 6 in this embodiment will be described with reference to FIGS. 5 and 6. FIG. 5(a) and 5(b) are explanatory diagrams of each process of the variable length packet sorting section 61 and the stuffing bit adding section 62 in the transmission server 6 of one embodiment according to the present invention, respectively. 6(a) and 6(b) are explanatory diagrams of each process of the error correction coding unit 63, the stuffing bit removal unit 64, and the IP packet generation unit 65 in the transmission server 6 of one embodiment according to the present invention, respectively. is.

First, as shown in FIG. 5A, the variable-length packet sorting unit 61 in the transmission server 6 accumulates the transmission data of the same broadcast program as that transmitted from the transmission device 2 in the form of variable-length packets in the order of input. , a 2-byte sequence header is added to the beginning of each variable-length packet. The sequence header added to each variable-length packet includes at least a sequence number indicating the input order of each variable-length packet (in the illustrated example, exemplified as "1" to "22814"), preferably for error correction. It contains information about the coding rate of coding and information identifying which broadcast program the variable-length packet belongs to. Here, the information about the coding rate of error correction coding and the information identifying which broadcast program the variable-length packet belongs to may be omitted if they are predetermined between transmission and reception. From the sequence number, it is possible to identify which variable length packet is the transmission data of the broadcast program.

Furthermore, as shown in FIG. 5(a), the variable-length packet sorting unit 61 sets the coding rate of the error correction coding in the subsequent error correction coding unit 63 (in the illustrated example, the LDPC coding rate of 61/120 ), a predetermined number of variable -length packets that depend on the coding rate of error correction coding (information obtained by excluding the LDPC code parity length of 22066 bits from the code length of 44880 bits in the horizontal direction in the figure Determine the number of packets 22814) corresponding to the length 22814 bits.

Subsequently, as shown in FIG. 5(b), the variable-length packet sorting unit 61 sorts packets in descending order based on the packet length, as shown in FIG. 5(b-1), or ), the variable-length packets to which the sequence headers are added are regularly rearranged by rearranging in ascending order based on the packet length. That is, in the preferred example shown in FIG. 5B, the variable-length packet sorting unit 61 rearranges the variable-length packets, which are information lengths, according to the packet lengths in a stepwise left-justified or right-justified manner.

As an example of rearranging individual variable-length packets, the maximum packet length of the variable-length packets may be set to 1000 bytes, and the variable size of the variable-length packets may be of a fixed type. For example, 50-byte steps, ie, 300, 350, 400, . If the number of packets is 1800 for both and the number of packets for the variable length packet of 300 bytes is 1214, the number of packets corresponding to the information length of 22814 bits with the coding rate of 61/120 is 22814.

Next, as shown in FIG. 5B, the stuffing bit addition unit 62 in the transmission server 6 adds the longest packet length (for example, 1000 bytes) among the predetermined number of variable length packets after regular rearrangement. variable-length packet is the longest)), a known pattern between transmission and reception (bits of all “0” or “1”, or bits of “0” and “1”) Add stuffing bits consisting of regular bit patterns).

Subsequently, as shown in FIG. 6(a) (FIG. 6(a-1) is an example of sorting in descending order, FIG. 6(a-2) is an example of sorting in ascending order), error correction coding in the transmission server 6 The unit 63 performs LDPC processing on the predetermined number of variable-length packets (the number of packets corresponding to the information length is 22814) to which stuffing bits are added, in a direction orthogonal to the length direction of the variable-length packets, including the sequence header. LDPC encoding processing is performed with a block size of a fixed length of 44880 bits using a parity check matrix corresponding to the encoding rate. In this example, the error correction coding unit 63 is based on the same processing as the LDPC code used in the error correction coding unit 21 in the transmission device 2, and is independent of the transmission device 2 related to broadcasting. A correction frame is formed, LDPC encoding is performed, and 22066 parity bits of the LDPC code are added when the LDPC encoding rate is 61/120, for example.

In general, when the maximum size of the packet length of the variable-length packet to be encoded is N bytes, the error correction encoder 63 includes a 2-byte sequence header and LDPC encoding processing is performed (N+2)×8 times in the direction. For this reason, for example, when the coding rate is 61/120 and the maximum size of the packet length of the variable-length packet to be encoded is 1000 bytes, (1000+2)×8=8016 in the direction orthogonal to the length direction of the variable-length packet. LDPC encoding is performed twice. At this time, the total number of parity bit areas generated by LDPC encoding is 22066×(1002×8) bits.

Subsequently, as shown in FIG. 6(b) (FIG. 6(b-1) is an example of sorting in descending order, and FIG. 6(b-2) is an example of sorting in ascending order), the stuffing bit removing unit in the transmission server 6 64 removes the stuffing bits added by the stuffing bit adding unit 62 after the error correction encoding processing by the error correction encoding unit 63, and converts the information of the variable length packet including the sequence header and the parity bit area into the variable length packet. Extract along the length of

Finally, as shown in FIG. 6(b) (FIG. 6(b-1) is an example of sorting in descending order, FIG. 6(b-2) is an example of sorting in ascending order), the IP packet generator in the transmission server 6 65 sequentially converts the information of the variable-length packet including the sequence header extracted in the length direction of the variable- length packet and the information of the parity bit area into IP packets and transmits them to the receiver 5 via the IP network 8 .

(Operation of receiving device)
A specific operation of the receiver 5 in this embodiment will be described below with reference to FIGS. 7 and 8. FIG. 7(a) and 7(b) are explanatory diagrams of respective processes of the IP packet receiving section 54, the stuffing bit adding section 55, and the error correction decoding section 56 in the receiving device 5 of one embodiment according to the present invention. 8(a) and 8(b) are explanatory diagrams of the processing of the stuffing bit removing section 57 and the variable length packet sorting section 58, respectively, in the receiving device 5 according to one embodiment of the present invention.

First, the receiving device 5 in this embodiment operates in the same manner as described in ARIB STD-B44 for receiving broadcast programs, and the demodulator 51 emits radio waves from the transmitting device 2 via the receiving antenna 5a. The modulated wave signal is received and demodulated, the error correction decoding section 52 reconstructs the error correction frame constituting the code length of the error correction code, and the error correction coding processing of the error correction coding section 21 in the transmission device 2 is performed. is performed to generate received data.

On the other hand, the receiving device 5 in this embodiment can receive IP packets related to the broadcast program via the IP network 8 .

First, as shown in FIG. 7(a) (FIG. 7(a-1) is an example of sorting in descending order, FIG. 7(a-2) is an example of sorting in ascending order), the receiver 5 IP packet receiving unit 54 receives IP packets related to the broadcast program from transmission server 6 via IP network 8, and configures error correction frames in error correction decoding unit 56 based on the header information of the IP packets. is divided in order by the predetermined number of packets, and output to stuffing bit adding section 55 . Here, the IP packet transmitted from the transmission server 6 may be lost or discarded on the IP network 8. As shown in FIG. It is not always possible to receive all of the IP packets received, and some of the IP packets may be lost when they are input. Allowed.

Subsequently, as shown in FIG. 7(b), the stuffing bit addition unit 55 in the receiving device 5 sequentially stores IP packets starting with a predetermined number of packets for forming an error correction frame. As encoded data, the sequence header, variable-length packets, and parity bit information are extracted, and from the regularity of the arrangement of each variable-length packet (Fig. FIG. 7(b-2) is an example of sorting in ascending order, and stuffing bits having a known pattern between the transmission server 6 side and the corresponding transmission/reception are predicted and added. Here, the stuffing bit adding unit 55 predicts and adds the stuffing bits including the lost IP packet.

Subsequently, as shown in FIG. 7(b) (FIG. 7(b-1) is an example of sorting in descending order, FIG. 7(b-2) is an example of sorting in ascending order), the receiving device The error correction decoding unit 56 in 5 corresponds to the error correction encoding unit 63 on the transmission server 6 side in the direction orthogonal to the length direction of the variable-length packet for the encoded data obtained from the stuffing bit addition unit 55. The error correction frame is reconstructed, likelihood determination is performed, decoding processing is performed based on the parity check matrix table corresponding to the coding rate corresponding to the error correction encoding processing of the LDPC code in the transmission server 6, and error correction decoding is performed. Generate later data.

In this way, the addition of stuffing bits by the stuffing bit addition unit 55 and the LDPC decoding processing in the direction orthogonal to the length direction of the variable-length packet by the error correction decoding unit 56, the lost IP on the IP network 8 The bit part of the packet can be compensated with known stuffing bits with high likelihood, and compared to the case where rearrangement and stuffing bits are not added, LDPC decoding performance can be improved due to the increase in known information. As a result, the lost IP packet can be restored.

Subsequently, as shown in FIG. 8(a) (FIG. 8(a-1) is an example of sorting in descending order, FIG. 8(a-2) is an example of sorting in ascending order), the receiving device A stuffing bit removing unit 57 in 5 removes the stuffing bits added by the stuffing bit adding unit 55 from the data after error correction decoding, and extracts an error-corrected variable-length packet.

Subsequently, as shown in FIG. 8(b), the variable-length packet sorting unit 58 in the receiving device 5 adds a sequence number (in the illustrated example, "1 ” to “22814”), the regular sorting by the variable-length packet sorting unit 61 on the transmission server 6 side is reversed, that is, the sorting is performed so as to restore the variable-length packets of the transmission data. , removes the sequence header added to each variable-length packet, extracts the received data, and outputs it to the received data switching/synthesizing unit 59 . In addition, when there are a plurality of variable-length packets of the same packet length, the variable-length packet sorting unit 58 arranges them in a predetermined order between transmission and reception, which is chronologically leading (or trailing). change.

Finally, the received data switching/synthesizing unit 59 in the receiving device 5 combines the received data obtained from the error correction decoding unit 52 via the broadcast transmission line by the broadcast reception and the received data via the IP network 8 obtained from the variable length packet sorting unit 58 The received data is switched or combined and output externally in a reproducible manner.

(supplement)
By the way, in the above-described embodiment, the variable-length packet sorting unit 61 regularly sorts the predetermined number of variable -length packets in the input order. are all the same packet length, add a sequence header that indicates the packet order without performing the rearrangement, and simply extract a predetermined number of variable-length packets in the order of input, in order of precedence in chronological order. (or it is also possible to make them in descending order). That is, since the predetermined number of variable-length packets in the input order all have the same packet length, the processing of the stuffing bit addition unit 62 can be omitted. Further, when the processing of the stuffing bit adding unit 62 is omitted, the processing of the stuffing bit removing unit 64 can also be omitted. Then, the IP packet generator 65 sequentially transmits IP packets composed of data after error correction processing to the receiving device 5 as described above.

In this case, the receiver 5 extracts the predetermined number of variable-length packets by referring to the sequence header among the IP packets sequentially received by the IP packet receiver 54, and omits the processing of the stuffing bit adder 55. and output to the error correction decoding unit 56. At this time, the error correction decoding unit 56 performs error correction decoding processing on the predetermined number of variable length packets. output to Then, the variable-length packet sorting unit 58 outputs the predetermined number of variable-length packets to the reception data switching/synthesizing unit 59 in the order in which they are arranged.

Therefore, when the predetermined number of variable-length packets to be processed all have the same packet length, the processing related to addition and removal of stuffing bits can be omitted. Furthermore, it is known in advance that all IP packets constituting transmission data of a broadcast program transmitted between the transmission server 6 and the reception device 5 have the same packet length, and are used for error correction codes. If the coding rate is also known, the processing related to the addition of the sequence header by the transmission server 6 and the removal of the sequence header by the reception device 5 can also be omitted.

As described above, the transmission server 6 according to the embodiment of the present invention inputs the transmission data of the broadcast program to be transmitted via the broadcast transmission line by the transmission device 2 (or the transmission device 3) in the form of variable-length packets, Based on the same encoding method as the error correction encoding method that processes error correction frames with a constant code length used in the transmission device 2 (or transmission device 3), and independent of the transmission device 2 (or transmission device 3) Error correction coding processing is performed at the coding rate, IP packetization is performed, and the IP packet is transmitted to the receiving device 5 via the IP network 8 .

In addition, the transmission server 6 adds a sequence header indicating the order of the packets to the input variable-length packets, and regularly rearranges the predetermined number of variable-length packets that depend on the coding rate of the error correction coding. Descending order or ascending order), stuffing bits are added in a predictable manner on the receiving device 5 side, error correction coding is performed in a direction orthogonal to the length direction of the variable-length packet, and the stuffing bits are removed. The information after the error correction coding is converted into IP packets sequentially in the length direction of the variable-length packet and transmitted to the receiver 5 via the IP network 8 .

In particular, in the transmitting device 2, based on the scarcity of frequencies for satellite broadcasting in the 12 GHz band, a broadcasting transmission path of the 21 GHz band satellite frequency that enables large-capacity transmission is used, and a certain code like an advanced satellite broadcasting system is used. It is assumed that transmission data of a broadcast program is transmitted to the receiving device 5 using an LDPC code of length 44880 bits. In such a case, the transmission server 6 according to one embodiment of the present invention applies the same processing as the LDPC code in the transmission device 2 to the transmission data transmitted via the IP network 8, and Error correction coding is performed at a coding rate independent of that of device 3).

Therefore, even if the transmission data of a broadcast program requires a large amount of transmission data, it can be transmitted. By using an error correction coding method that is common between broadcasting and IP transmission, the affinity between broadcasting and IP transmission is high. Furthermore, it is possible to compensate for loss of IP packets occurring in the IP network 8 while compensating for poor reception on the receiving device 5 side due to deterioration of transmission conditions related to the broadcast transmission path.

Then, the receiving device 5 according to one embodiment of the present invention receives IP packets related to the broadcast program from the transmission server 6 via the IP network 8 separately from the broadcast reception from the transmission device 2 (or the transmission device 3). , the sequence header, variable-length packets, and parity bit information are extracted as stored encoded data in order from a predetermined number of IP packets for forming an error correction frame. Subsequently, the receiving device 5 predicts and adds stuffing bits corresponding to the transmission server 6 side from the regularity of arrangement of each variable-length packet, and performs error correction decoding corresponding to the error correction encoding in the transmission server 6. conduct. Then, the receiving device 5 removes the stuffing bits added by the receiving side after the error correction decoding, and performs rearrangement to reverse the regular rearrangement by the transmission server 6 based on the information of the sequence header. Received data is extracted from the rearranged variable-length packets, and the data received by broadcast reception and the data received via the IP network 8 are switched or combined, and output externally in a reproducible manner.

Therefore, the receiving device 5 according to one embodiment of the present invention, aside from receiving the broadcast, removes the stuffing bits that act to improve the accuracy of error correction from the data received from the transmission server 6. In spite of this, it is possible to easily predict and add continuous stuffing bits without division, so that error correction decoding corresponding to the transmission side can be performed.

As a result, the receiving device 5 according to the embodiment of the present invention can receive the IP packet related to the broadcast program lost in the IP network 8, compared to the form of receiving the IP packet subjected to error correction processing without using stuffing bits. The decoding performance of received data from packets can be improved. Therefore, the receiving apparatus according to the present invention can efficiently perform the Moreover, it is possible to restore broadcast program data with high accuracy.

A program for causing each means of the computer functioning as the transmission server 6 to function can be preferably used for the above-described one embodiment and one example. Further, an IP packet receiving unit 54, a stuffing bit adding unit 55, an error correction decoding unit 56, a stuffing bit removing unit 57, a variable length packet sorting unit 58, and a receiving A program for causing each means of the data switching/synthesizing section 59 to function by a computer can be preferably used. Specifically, a control unit for controlling each means can be configured by a central processing unit (CPU) in a computer, and at least a storage unit for appropriately storing programs required to operate each means It can be configured with one memory. That is, by causing the CPU of such a computer to execute the program, the functions of the above-described means can be realized. Further, a program for realizing the function of each means can be stored in a predetermined area of the aforementioned storage section (memory). Such a storage unit can be configured with a RAM or ROM inside the device, or can be configured with an external storage device (eg, hard disk). Also, such a program can be made up of a part of software (stored in a ROM or an external storage device) on an OS used in a computer. Furthermore, a program for causing such a computer to function as each means can be recorded in a computer-readable recording medium. Moreover, each of the means described above can be configured as a part of hardware or software, and can be realized by combining them.

Although the above embodiments have been described as representative examples, it will be apparent to those skilled in the art that many modifications and substitutions may be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as limited by the above-described embodiment and example, but only by the scope of the claims.

According to the present invention, it is possible to configure a transmission system that enables a service of large-capacity transmission of broadcast programs and enables data transmission by compensating for poor reception due to deterioration of transmission conditions related to broadcast transmission paths. It is useful for large-capacity transmission of broadcast programs.

1 Transmission system 2 Transmission device for satellite broadcasting transmission line 2a Transmission antenna for satellite broadcasting transmission line 3 Transmission device for terrestrial broadcasting transmission line 3a Transmission antenna for terrestrial broadcasting transmission line 4 Broadcasting satellite 5 Receiving device 5a Satellite broadcasting transmission line 5b Receiving antenna for terrestrial broadcasting transmission line 6 Transmission server 8 IP network 21 Error correction coding unit 22 Modulation unit 51 Demodulation unit 52 Error correction decoding unit 53 Check matrix table storage unit 54 IP packet reception unit 55 Stack Finging bit addition unit 56 Error correction decoding unit 57 Stuffing bit removal unit 58 Variable length packet sorting unit 59 Received data switching/combining unit 61 Variable length packet sorting unit 62 Stuffing bit addition unit 63 Error correction coding unit 64 Stuffing bit removal Unit 65 IP packet generation unit

Claims (8)

A transmission server that inputs transmission data of a broadcast program in the form of variable-length packets, converts the IP packets into IP packets, and transmits the IP packets to a receiving device,
Broadcast program transmission data to be transmitted via a broadcast transmission path by a transmission device is stored in the form of variable-length packets in the order of input, and a sequence header indicating the packet order is added to the head of each variable-length packet to determine the order of input. variable-length packet sorting means for regularly sorting a predetermined number of variable-length packets;
Among the predetermined number of variable-length packets after regular rearrangement, stuffing bits having a known pattern between transmission and reception are added to variable-length packets with packet lengths that are empty when the longest packet length is used as a reference. stuffing bit adding means;
An error correction frame having a constant code length, including the sequence header, used in the transmitting device for the predetermined number of variable length packets to which the stuffing bits are added, in a direction orthogonal to the length direction of the variable length packets. Error correction encoding means for performing error correction encoding processing by configuring an error correction frame based on the same encoding method as the error correction encoding method processed in and at a coding rate independent of the transmitting device;
The stuffing bits are removed after the error correction coding process, and the variable length packet including the sequence header and the information of the parity bit area added by the error correction coding process are extracted in the length direction of the variable length packet. stuffing bit removal means;
The variable-length packet including the sequence header extracted in the length direction of the variable- length packet and the information of the parity bit area are sequentially IP-packetized so that the transmission data from the transmission device can be received via the IP network. IP packet generation means for transmission to a receiving device;
A transmission server comprising: The variable-length packet sorting means sorts the predetermined number of variable-length packets in the input order in descending order or ascending order based on the packet length so that addition of the stuffing bit can be predicted on the receiving device side. The transmission server according to claim 1 , characterized by: The error correction coding scheme used in the transmitting device includes an LDPC code,
The error correction coding means is based on the same processing as the LDPC code and performs error correction coding processing by configuring an error correction frame at a coding rate independent of the transmission device, 3. Transmission server according to claim 1 or 2 . A transmission device for digital broadcasting,
4. A transmission device comprising the transmission server according to any one of claims 1 to 3 inside the device. An IP packet relating to the broadcast program is received via an IP network from the transmission server according to any one of claims 1 to 3 , and the error correction frame used by the transmission server is referenced by referring to the sequence header. IP packet receiving means for sequentially extracting a predetermined number of IP packets for reconstructing the
From the predetermined number of IP packets, the sequence header, variable length packets, and parity bit information are sequentially extracted as the stored encoded data, and from the regularity of the arrangement of the variable length packets, the transmission server stuffing bit adding means for predicting and adding used stuffing bits;
The error correction frame used by the transmission server is reconstructed for the encoded data to which the stuffing bits have been added, likelihood determination is performed, and the encoding rate corresponding to the error correction encoding processing in the transmission server is set. error correction decoding means for generating data after error correction decoding by performing decoding processing according to the
Stuffing bit removal means for removing the stuffing bits from data after error correction decoding and extracting an error-corrected variable-length packet;
By referring to the sequence header, the regular sorting by the transmission server is reversed, and sorting is performed so as to restore the variable length packets of the transmission data, and the sequence header added to each variable length packet is deleted. variable length packet alignment means for extracting received data by
Switching between data received by broadcast reception obtained from the transmitting device via a broadcast transmission path and data received via an IP network obtained from the variable-length packet sorting means , or switching received data for combining and outputting to the outside in a reproducible manner / synthesis means;
A receiving device comprising: The error correction decoding means is a parity check matrix corresponding to a predetermined type of coding rate, which is used in common with decoding processing of an error correction coding system related to broadcast reception obtained from the transmission device via a broadcast transmission line. 6. The receiving apparatus according to claim 5 , wherein said table is referred to and said decoding process is performed according to said coding rate. A program for causing a computer to function as the transmission server according to any one of claims 1 to 3 . A program for causing a computer to function as the receiving device according to claim 5 or 6 .

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