JP5011239B2 - Broadcast packet generator, data supplement server, receiving terminal, and program thereof - Google Patents

Description

  The present invention relates to a technology of a digital broadcasting system in which a receiving terminal that receives a file distributed via a broadcast transmission path of digital broadcasting acquires unacquired data in the file from a data supplement server via a communication line, in particular. The present invention relates to a technique that takes into account the data size of information transmitted through a broadcast transmission path and a communication line.

  In the field of communications, information is transmitted using IP (Internet Protocol) packets in communication lines represented by the Internet. In communication lines, for example, considering an Ethernet (registered trademark) MTU (Maximum Transfer Unit) and considering that packet loss occurs, an IP packet has a size of 1.5 KB or less. It is common to transmit. One reason for this is that in Ethernet (registered trademark), the size that can be stored in a MAC frame without dividing a packet to be transmitted is 1500 bytes.

  For example, when an IP packet is transmitted using UDP (User Datagram Protocol), an IPv4 / UDP packet 801 shown in FIG. 11A includes an IPv4 header (IPv4 Header) 811 and a UDP header (UDP) in the header portion 810. Header) 812, and data portion (payload) 820 stores data 821. 11B includes an IPv6 header (IPv6 Header) 911, a UDP header (UDP Header) 912, an extension header (IPv6_extension_header) 913, and data. Data 921 is stored in the part (payload) 920.

  On the other hand, in the field of broadcasting, a TLV (Type-Length-Value) multiplexing method has been proposed as a new BS digital broadcasting (advanced satellite digital broadcasting) broadcasting method after 2011 when BS analog broadcasting ends. By using this, it becomes possible to transmit IP packets not only on communication lines but also on broadcast transmission paths (see Non-Patent Document 1 and Non-Patent Document 2). Since it is not necessary to perform path control using information on the IP header and the UDP header on the broadcast transmission path, the IP header and the UDP header can be compressed (see Non-Patent Document 2). In general, the transmission quality of satellite broadcasting is high, and pseudo error-free transmission is possible in a state where a reception C / N (Carrier to Noise Ratio) can be ensured (see Non-Patent Document 3).

  When considering the MTU for an IP packet to be transmitted on the broadcast transmission path, the IP packet no longer passes through the wide-area communication line network on the broadcast transmission path, so the range for considering the MTU is received from the tuner unit to be demodulated. The range is up to the application. For this reason, the size of the IP packet to be transmitted through the broadcast transmission path can be increased.

  According to the standards and standard specifications (TS: Technical Specification) for mobile terminals, after content is distributed over a one-way but broadcast-type broadcast line, some content may be lost or a transmission path error may occur. A protocol for ensuring the integrity of content by requesting a generated defect portion using a communication line is shown.

  For example, the IP datacast in DVB-H (Digital Video Broadcasting-Handheld: one of mobile television standards) adopted by ETSI (European Telecommunications Standards Institute) (Non-patented) Reference 4). In addition, MBMS (Multimedia Broadcast / Multicast Service) indicating a content distribution service for mobile terminals in 3GPP (3rd Generation Partnership Project: standardization project of third generation mobile communication system) corresponds to this (see Non-Patent Document 5).

  Either DVB-H or MBMS broadcasts IP packets via a broadcast transmission path, but may be intended for mobile terminals and transmission quality is not as good as that for fixed terminals. Therefore, the size of the IP packet multiplexed on the broadcast transmission path is small. For example, in DVB-H, the size of the IP packet multiplexed on the broadcast transmission path is 512 bytes (see Non-Patent Document 6).

Also, a technique is known in which a digital broadcast receiving apparatus as a fixed terminal acquires unacquired data using a communication line when data received from a broadcast system via a broadcast transmission path is missing ( (See Patent Document 1). In this technology, a module (file) to be transmitted by broadcasting is divided into DDB (Download Data Block) having a constant size and then incorporated into a DSM-CC (Digital Storage Media-Command and Control) section by a data carousel. Is transmitting. The section includes DII (Download Info Indication) for reproducing the module from the DDB. In DII, URL information to the server of the broadcasting system, the size of the module transmitted from the broadcasting system, and the number of DDBs constituting the module are described. As a result, the digital broadcast receiving apparatus calculates the range of the unacquired data in the module, and uses the calculated byte range data (for example, 50 bytes of data in the range of 1200 to 1250 bytes) using the communication line. To request. Note that the technique described in Patent Document 1 does not consider the size of information transmitted through each transmission path.
JP 2002-118812 (paragraphs 0070-0071, FIG. 9) Shuichi Aoki, Satoshi Nishimura, Katsunori Aoki, Takeshi Kimura, “A Study on IP Packet Transmission Method in Advanced BS Digital Broadcasting”, Video Information Media Society, 2007 Winter Conference, Section 3 Broadcasting Technology 3-3, Dec. 2007 Radio Industry Association Multiplexing Working Group, “Advanced Satellite Digital Broadcasting Multiplexing System Report Draft (Technical Conditions)”, Ministry of Internal Affairs and Communications Information and Communications Council, June 17, 2008 Edited by the Institute of Image Information and Television Engineers, supervised by Yoshizumi Eto and Toshinobu Kaneko, "Error-correcting codes and their applications", Ohm, 1996 ETSI TS 102 472, “DVB; IP Datacast over DVB-H: Content Delivery Protocols”, (2006-12) 3GPP TS 26.346, “Multimedia Broadcast / Multicast Service (MBMS); Protocols and codecs” ETSI TS 102 591, “DVB; IP Datacast over DVB-H: Content Delivery Protocols (CDP) Implementation Guidelines”, (2007-10)

  Similar to conventional DVB-H and MBMS, a download application that broadcasts contents (files) on a satellite transmission line and supplements only information that has been lost due to a transmission line error using a communication line, for example. A method of performing for a fixed terminal using broadcasting is considered. In advanced satellite digital broadcasting, IP packets can be transmitted without being divided by using the TLV multiplexing method. For this reason, if the packet format on the communication line and the packet format on the broadcast transmission path are exactly the same, when a part of the content is lost or a loss occurs due to a transmission path error, Unlike the technique described in Document 1, it is not necessary to use information such as the byte position from the beginning of the file and the missing size, and the missing portion can be easily complemented on a packet basis using a communication line.

  Non-Patent Document 1 describes that according to the TLV multiplexing method, the overhead of header information added for each packet becomes smaller as the payload size is larger in packet transmission. That is, the larger the payload size, the more efficient transmission becomes possible. However, the larger the payload size, the larger the information lost when a packet is lost. For this reason, it is necessary to determine the payload size of the packet to be transmitted in consideration of the quality of the transmission path to be used. For example, the transmission path quality of the satellite transmission path is close to pseudo error free, and the payload size of the IP packet to be transmitted through the satellite transmission path can be increased.

  However, in the conventional technology, when complementing in units of packets using a communication line, the size of the packet transmitted on the broadcast transmission path is treated as being equal to the bucket size used on the communication line. Therefore, for a download application that can complement a file received from a broadcast transmission line using a communication line, the size of the IP packet to be transmitted on the broadcast transmission line is limited by the MTU of the communication line. Only a payload size of about 5 KB can be used. In other words, if a satellite transmission path with high transmission path quality is used, it is possible to increase the payload size of an IP packet to be transmitted by broadcasting. There is a problem that only IP packets of a size limited by the MTU of the communication line can be transmitted, and the transmission efficiency of IP packets to be transmitted by broadcasting is lowered.

  The present invention has been made in view of the above problems, and a broadcast transmission path in a digital broadcasting system that supplements missing data in a receiving terminal that has received a file transmitted through the broadcast transmission path using a communication line. An object of the present invention is to provide a technology capable of efficiently transmitting IP packets.

  The present invention was devised to achieve the above-mentioned object. First, the broadcast packet generation device according to claim 1 is provided as an IP packet for each file fragment obtained by dividing a file via a broadcast transmission path. A broadcast packet generation device that generates a broadcast IP packet to be distributed, and a receiving terminal that has received a file transmitted as the broadcast IP packet communicates an unacquired file fragment in the received file from a data supplement server The broadcast packet generation device in a digital broadcast system that ensures the integrity of a file received via the broadcast transmission path by acquiring via a line, comprising: a file dividing means; and a broadcast packet generation means. It was set as the structure provided.

  According to such a configuration, the broadcast packet generation device uses the file dividing unit to determine the size of the data stored in the data portion of the packet in which the file fragment size is transmitted from the data complementing server to the receiving terminal for each file. The file is divided so as to be larger and to have a prescribed size obtained by multiplying the size by a predetermined integer value. The broadcast packet generation device stores the specific information for specifying the file fragment in the header portion and also stores the file fragment in the data portion by the broadcast packet generation means for downloading the file. An IP packet is generated.

  Also, the broadcast packet generation device according to claim 2 is the broadcast packet generation device according to claim 1, wherein the specific information for specifying the file fragment includes an identifier of a file including the file fragment, The download header has a block number indicating a position in the file of a block composed of a plurality of file fragments including the file fragment, and a sequence number indicating the position of the file fragment in the block.

  According to such a configuration, the broadcast packet generation apparatus divides a file into a plurality of blocks and designates a file fragment in a unit of the second hierarchy obtained by further dividing the block. As compared with the case where the file fragment is specified in the above, it is possible to quickly identify the target file fragment in the entire file from the specific information identifying the file fragment.

  Further, the data supplement server according to claim 3 is a specification for specifying the file fragment including the file fragment of the specified size generated by the broadcast packet generation device according to claim 1 or 2 in a data part. A complementary IP packet for complementing the broadcast IP packet is received via a communication line for a receiving terminal that has received a file transmitted as a broadcast IP packet including information in a header portion via a broadcast transmission path. The data supplement server to be transmitted to the receiving terminal includes a supplement request IP packet receiving means, a complement IP packet generating means, and a complement IP packet transmitting means.

  According to this configuration, the data complementing server receives the complement request IP packet including the specific information for identifying the unacquired file fragment in the file from the receiving terminal by the complement request IP packet receiving unit. Then, the data complementing server uses the complementing IP packet generating means to determine the unacquired file fragment as a predetermined integer value that defines the prescribed size based on the specific information that identifies the unacquired file fragment. A specification for dividing the partial file fragment into equal data sizes, adding division order information indicating the position in the file fragment to the divided partial file fragment, and identifying the file fragment to complement the file fragment The complementary IP packet is generated in which the information and the division order information are stored in the header portion and the partial file fragment is stored in the data portion. The data complementing server transmits the complementing IP packet to the receiving terminal by the complementing IP packet transmitting unit.

  According to a fourth aspect of the present invention, there is provided the data complementing server according to the third aspect, further comprising a file information storage unit and a division number determining unit.

  According to such a configuration, the data complementing server stores the prescribed size of the file fragment included in the file for each file transmitted via the broadcast transmission path in the file information storage unit. Then, the data complementing server determines the number of unacquired file fragments from the file information storage unit based on the specific information for identifying the unacquired file fragment included in the complement request IP packet by the division number determining unit. A prescribed size is extracted, and a predetermined integer value that defines the extracted prescribed size is determined as the division number of the file fragment. Then, the data complementing server divides the unacquired file fragment by the determined number of divisions by the complementing IP packet generation unit.

  In addition, the receiving terminal according to claim 5 includes identification information for specifying the file fragment including the file fragment of the specified size generated by the broadcast packet generation device according to claim 1 or 2 in a data portion. And a plurality of unacquired file fragments in the received file from the data complementing server according to claim 3. A receiving terminal that obtains as a complementary IP packet via a communication line, a broadcast receiving means, a loss determining means, a complementary request IP packet generating means, a complementary request IP packet transmitting means, and a complementary IP The packet receiving means, the complementary file fragment construction means, and the file restoration means are provided.

  According to this configuration, the receiving terminal receives the broadcast IP packet by the broadcast receiving means. Then, when the receiving terminal restores the file by connecting the file fragments included in each received broadcast IP packet based on the information of the header part of the received broadcast IP packet by the loss determination unit Determine whether a file fragment is missing. Then, when the file fragment is missing by the complement request IP packet generating means, the receiving terminal uses the header of the broadcast IP packet corresponding to the file fragment as specific information for identifying the unacquired file fragment. The complement request IP packet including the information stored in the section is generated. The receiving terminal transmits the generated complement request IP packet to the data complement server by the complement request IP packet transmitting means. Then, the receiving terminal receives the complementary IP packet from the data complementing server by the complementing IP packet receiving means by a predetermined integer number that defines a prescribed size of the file fragment per one complementing request IP packet. Receive. Then, the receiving terminal connects the partial file fragments in order based on the division order information included in the received complementary IP packets by the complementary file fragment constructing unit, and the unacquired file Build fragments. Then, the receiving terminal connects the constructed file fragment to the missing position in the file where the file fragment is missing by the file repair means.

  The broadcast packet generation program according to claim 6, wherein the broadcast packet generation device generates a broadcast IP packet that is distributed as an IP packet via a broadcast transmission path for each file fragment obtained by dividing a file; A file received via the broadcast transmission path by a receiving terminal that has received a file transmitted as a broadcast IP packet by acquiring an unacquired file fragment in the received file from a data supplement server via a communication line In the digital broadcasting system that ensures the integrity of the broadcast, the computer constituting the broadcast packet generation device is caused to function as a file dividing unit and a broadcast packet generation unit in order to generate the broadcast IP packet.

  According to such a configuration, the broadcast packet generation program uses the file dividing unit to determine the size of the data stored in the data part of the packet in which the size of the file fragment is transmitted from the data complementing server to the receiving terminal for each file. The file is divided so as to be larger and to have a prescribed size obtained by multiplying the size by a predetermined integer value. The broadcast packet generation program stores the specific information for specifying the file fragment in the header portion and the file fragment in the data portion for downloading the file by the broadcast packet generation means. An IP packet is generated.

  According to a seventh aspect of the present invention, there is provided a data supplement program for specifying a file fragment including a file fragment of the specified size generated by the broadcast packet generating device according to the first or second aspect in a data portion. A complementary IP packet for complementing the broadcast IP packet is received via a communication line for a receiving terminal that has received a file transmitted as a broadcast IP packet including information in a header portion via a broadcast transmission path. In order to transmit to the receiving terminal, the computer is caused to function as a complement request IP packet receiving means, a complement IP packet generating means, and a complement IP packet transmitting means.

  According to this configuration, the data complementing program receives the complement request IP packet including the specific information for identifying the unacquired file fragment in the file from the receiving terminal by the complement request IP packet receiving unit. Then, the data complementing program uses the complementing IP packet generation means based on the specific information for identifying the unacquired file fragment to set the unacquired file fragment to a predetermined number of integer values defining the specified size. A specification for dividing the partial file fragment into equal data sizes, adding division order information indicating the position in the file fragment to the divided partial file fragment, and identifying the file fragment to complement the file fragment The complementary IP packet is generated in which the information and the division order information are stored in the header portion and the partial file fragment is stored in the data portion. The data complementing program transmits the complementing IP packet to the receiving terminal by the complementing IP packet transmitting unit.

  The file receiving program according to claim 8 is a specification for specifying the file fragment including the file fragment of the specified size generated by the broadcast packet generating device according to claim 1 or 2 in a data portion. 5. A file transmitted as a broadcast IP packet including information in a header portion is received via a broadcast transmission path, and unacquired file fragments in the received file are received from the data complementing server according to claim 3 or 4. In order to obtain a plurality of complementary IP packets via a communication line, a computer of a receiving terminal having broadcast receiving means for receiving the broadcast IP packet includes a loss determination means, a complementary request IP packet generating means, a complementary Functions as request IP packet transmission means, complementary IP packet reception means, complementary file fragment construction means, and file repair means It was decided to.

  According to such a configuration, the file reception program connects the file fragments included in each received broadcast IP packet based on the information of the header part of the received broadcast IP packet by the loss determination unit, and When restoring the file, it is determined whether or not the file fragment is missing. Then, when the file fragment is missing by the complement request IP packet generation means, the file reception program uses the broadcast IP packet corresponding to the file fragment as identification information for identifying the unacquired file fragment. A complement request IP packet including information stored in the header portion is generated. Then, the file reception program transmits the generated supplement request IP packet to the data supplement server by the supplement request IP packet transmitting means. Then, the file receiving program receives, from the data complementing server, the complementing IP packet receiving means by the number of the predetermined integer value that defines a prescribed size of the file fragment per one complementing request IP packet. Receive the packet. Then, the file reception program sequentially connects the partial file fragments based on the division order information included in the received complementary IP packets by the complementary file fragment construction unit, and the unacquired Build a file fragment. Then, the file receiving program connects the constructed file fragment to the missing position in the file where the file fragment is missing by the file repairing means.

  According to the broadcast packet generation device according to claim 1 or the broadcast packet generation program according to claim 6, the size of the file fragment when the file fragment constituting the file is transmitted as an IP packet from the broadcast transmission path. Is generated larger than the size of the data transmitted from the communication line and an integral multiple thereof, so that the file can be efficiently transmitted from the broadcast transmission path.

  According to the broadcast packet generation device of the second aspect, the target file fragment can be quickly specified in the entire file from the specification information for specifying the file fragment.

  According to the data complementing server according to claim 3 or the data complementing program according to claim 7, an unacquired file fragment requested from the receiving terminal is stored in a predetermined number of integers based on the prescribed size. The data is divided into partial file fragments having a uniform data size, and a complementary IP packet including division order information is transmitted to the receiving terminal via the communication line. Therefore, even if a file fragment efficiently transmitted as a broadcast IP packet from the broadcast transmission path in the file received by the receiving terminal is lost, data to be complemented can be easily generated and transmitted from the communication line. Can do.

  According to the data complementing server of claim 4, even if unacquired file fragments are requested in files having different file fragment sizes, data is supplemented each time in response to those requests. Can do. Therefore, it is possible to complement unacquired data in a file having a data size suitable for the type of video content, music content, etc. constituting the file with a single device.

  According to the receiving terminal according to claim 5 or the file receiving program according to claim 8, when missing data occurs in a file received as a broadcast IP packet transmitted on a broadcast transmission path, it is insufficient. Two or more integer complementing IP packets are acquired from the communication line for each broadcasting IP packet. Accordingly, it is possible to efficiently transfer a broadcast IP packet from a broadcast transmission path in which a file fragment having a data size larger than the MTU of the communication line and an integral multiple of the MTU is normally stored while ensuring data complementation from the communication line in preparation for an emergency. Can receive well.

  Hereinafter, the best mode (hereinafter referred to as “embodiment”) for implementing a broadcast packet generation device, a data supplement server, and a receiving terminal of the present invention will be described in detail with reference to the drawings.

[Outline of Advanced Satellite Digital Broadcasting System]
(Configuration of advanced satellite digital broadcasting system)
First, the configuration of the advanced satellite digital broadcasting system will be described with reference to FIGS. 1 to 3 as appropriate. FIG. 1 is a configuration diagram schematically showing an advanced satellite digital broadcasting system including a file transmission device, a data complementing server, and a receiving terminal according to an embodiment of the present invention. FIG. 2 is a sequence diagram showing an operation of complementing data loss when it occurs in the advanced satellite digital broadcasting system, and FIG. 3 is an explanatory diagram of data loss and the state of complementation.

  As shown in FIG. 1, the advanced satellite digital broadcast system 1 includes a file transmission device (broadcast packet generation device) 11, a transmission device 12, and a data complementing server 13 on the content provider 10 side. The receiving terminal 21 is provided on the person 20 side. Although illustration is omitted, it is assumed that there are a plurality of viewers 20 and receiving terminals 21.

  The file transmission device (broadcast packet generation device) 11 generates a broadcast IP packet 50 distributed via the broadcast transmission path 30 for each data unit (file fragment) obtained by dividing the content (file) to be broadcast. Is.

  The transmission device 12 distributes the broadcast IP packet 50 stored as content (file) in the file transmission device 11 via the broadcast transmission path 30. In the present embodiment, the broadcast transmission path 30 is a satellite broadcast transmission path via the artificial satellite 31, and is a new BS digital broadcast (advanced satellite digital broadcast) transmission path that can multiplex IP packets as TLVs. (See Non-Patent Documents 1 and 2).

  When the data complementing server 13 receives the complement requesting IP packet 60 from the receiving terminal 21 via the communication line 40, the data complementing server 13 replaces an unacquired data unit (file fragment) in the file received by the receiving terminal 21 with the complementing IP. The packet 70 is transmitted via the communication line 40. In FIG. 1, only one data supplement server 13 is illustrated, but the number of servers is not limited.

  As described above, there are two types of IP packets distributed by the content provider 10, that is, the broadcast IP packet 50 and the complementary IP packet 70. The payload size of the broadcast IP packet 50 is larger than the payload size of the complementary IP packet 70 and is an integral multiple thereof. In FIG. 1, as an example, the payload size of the broadcast IP packet 50 is three times the payload size of the complementary IP packet 70. That is, when one broadcast IP packet 50 is missed in the receiving terminal 21, the data supplement server 13 supplements the data corresponding to one broadcast IP packet 50, so that three supplement IP packets 70a. , 70 b, 70 c are transmitted to the receiving terminal 21 via the communication line 40. If not particularly distinguished, it is referred to as a complementary IP packet 70.

  The receiving terminal 21 is configured to be able to use both the broadcast transmission path 30 and the communication line 40. The receiving terminal 21 is notified in advance of information necessary for receiving the broadcast IP packet 50 and information necessary for receiving the complementary IP packet 70 in the form of a program guide or the like. Here, the information necessary for receiving the broadcast IP packet 50 includes, for example, a program name, content identification information (file ID), distribution start time, distribution end time, broadcast channel, distributed group address, and the like. including. The information necessary for receiving the complementing IP packet 70 is information for requesting supplementation of missing information when the content (file) cannot be completely received only by receiving the broadcast. A list of data complementing servers 13 is included. In this list, the URL of the data complementing server 13 and the type of file to be complemented can be described.

(Processing flow in advanced satellite digital broadcasting system)
A processing flow in the advanced satellite digital broadcasting system shown in FIG. 1 will be described with reference to FIG. First, the file sending device 11 divides the content (file) to generate the broadcast IP packet 50 (step S1). The file sending device 11 stores the generated broadcast IP packet 50 and outputs it to the sending device 12 at a predetermined timing. Then, the transmission device 12 transmits the acquired broadcast IP packet 50 to the reception terminal 21 via the broadcast transmission path 30.

  The receiving terminal 21 configures the file by sequentially connecting data units (file fragments) included in the received broadcast IP packet 50. For example, if no transmission path error occurs, the receiving terminal 21 can receive the file correctly and completely. However, when a transmission path error occurs, the broadcast IP packet 50 in which the error is detected is discarded and does not reach the receiving application. Therefore, some data units constituting the file are lost, and part or all of the file cannot be constructed. For example, the file 80 shown in FIG. 3A is composed entirely of data areas 81, 82, 83, and after missing data units are complemented by receiving the broadcast again, the data area 82 is further stored. The defect remains. In the data area 82, as shown in FIG. 3B, the data unit group 84 is missing. In such a case, the receiving terminal 21 generates a complement request IP packet 60 indicating which data unit of which file is requested to be complemented (step S2).

  The receiving terminal 21 transmits the generated supplement request IP packet 60 to the data supplement server 13 via the communication line 40. When the data complementing server 13 obtains the complement request IP packet 60, the number of divisions indicating how much the broadcast IP packet 50 that is missing from the received file is sent in order to complement the requested data unit. Is determined (step S3). Further, in order to complement the requested data unit, the data complementing server 13 acquires the broadcast IP packet 50 from the file sending apparatus 11 storing the broadcast IP packet 50, and divides the data unit. Then, the complementary IP packets 70a, 70b, and 70c are generated (step S4). For example, as shown in FIG. 3B, one missing broadcast IP packet 50 is supplemented by three complementary IP packets 70a, 70b, and 70c. Then, the data complementing server 13 transmits the generated complementing IP packets 70 a, 70 b, 70 c to the receiving terminal 21 via the communication line 40.

  The receiving terminal 21 constructs a complementary file fragment (complementary fragment) in which data units of the same size included in the payloads of the received complementary IP packets 70a, 70b, and 70c are connected (step S5). Then, the receiving terminal 21 repairs the file in which the transmission path error has occurred by sequentially inserting the complementary fragments into the corresponding data area 82 of the missing data unit group 84 (step S6). As a result, as shown in FIG. 3C, each data unit (file fragment) is normally recorded in the data area 82, and the entire file can be normally configured.

[Configuration of each device of advanced satellite digital broadcasting system]
FIG. 4 is a block diagram schematically illustrating the configuration of the file transmission device and the data complementing server according to the embodiment of the present invention, and FIG. 5 schematically illustrates the configuration of the receiving terminal according to the embodiment of the present invention. It is a block diagram.

(File sending device)
The file transmission device (broadcast packet generation device) 11 includes an arithmetic device such as a CPU, a storage device such as a memory and a hard disk, an input device that detects input of information from the outside such as a mouse and a keyboard, and various external devices. It comprises an interface device that transmits and receives information, a computer that includes a display device such as an LCD (Liquid Crystal Display), and a program that is installed in the computer.

The file sending device 11 is realized by the hardware device and software cooperating to control the hardware resources described above by a program. As shown in FIG. Means 112, broadcast packet generation means 113, and file storage means 114 are provided.
The file input means 111 is a predetermined input interface for inputting content (file) to be broadcasted from the outside.

  The file dividing means 112 has a data unit (file fragment) size larger for each file than the data size stored in the data portion of the packet (complementary IP packet 70) transmitted from the data complementing server 13 to the receiving terminal 21. In addition, the file is divided so as to have a prescribed size obtained by multiplying the size by a predetermined integer value.

  The broadcast packet generation means 113 stores specific information for specifying a data unit (file fragment) in the header portion and downloads the data unit (file fragment) in the data portion in order to download a file in the receiving terminal 21. An IP packet 50 is generated. In the present embodiment, the broadcast IP packet 50 includes a download header as specific information in the header portion. The download header includes an identifier of a file in which the data unit of the data part is included, and a block number and a sequence number to which the data unit belongs. Here, the block number indicates the position in the file of the block including a plurality of data units, and the sequence number indicates the position of the data unit in the block. The broadcast IP packet 50 includes, for example, an IP header and a UDP header in addition to a download header in the header portion.

  The file accumulating unit 114 accumulates the broadcast IP packet 50 generated by the broadcast packet generating unit 113 as content (file) to be transmitted to the receiving terminal 21, and is configured by, for example, a general hard disk or the like. The

  Here, a specific example of the structure of the broadcast IP packet will be described with reference to FIGS. FIG. 6 is a diagram illustrating the structure of a broadcast IP packet, and FIG. 7 is a diagram illustrating the structure of a download header. As shown in FIG. 6A, the file (content) 301 is divided into a number of data units (Du: file fragments) 401. Among these, a predetermined number of data units (Du: file fragments) 401 form a block. For example, the file (content) 301 includes a plurality of (for example, K) blocks.

  As shown in FIG. 6B, a download header 421 is added to the data unit (file fragment) 401. As shown in FIG. 7, the download header 421 includes a total of 8 fields including a Transport File ID (file identifier) 501, a Block Number (block number) 502, and a Sequence Number (sequence number) 503 as a plurality of fields. A byte header. A Transport File ID (file identifier) 501 indicates which file is a divided data unit. In FIG. 7, if the block number 502 and the sequence number 503 are a total of 4 bytes, the number of bits in each field may be arbitrary.

  Thus, in the receiving terminal 21 that receives the broadcast IP packet 50 including the download header 421 in the header portion, the individual data unit 401 stored in the data portion of the broadcast IP packet 50 is changed to the block number 502 and the block. The sequence number 503 can be specified. In FIG. 6B, the download header 421 arranged on the right side of the data unit 401 is arranged above the data unit 401 as being layered in a stack form in FIG.

  In the present embodiment, the file transmission device 11 generates and transmits the broadcast IP packet 50A shown in FIG. The broadcast IP packet 50A has a format in which a download header 421 is added to the data unit 401, and an IP header and a UDP header 441 (hereinafter referred to as IP / UDP header 441) are added. Although the illustration of the IP / UDP header is omitted in FIG. 7, the IP / UDP header 441 in FIG. 7 is arranged on the upper layer of the download header 421.

  In the present embodiment, since the broadcast transmission path 30 is used as a transmission path for advanced satellite digital broadcasting, it is not necessary to perform path control using information in the IP / UDP header 441 on such a broadcast transmission path 30. For this reason, the IP / UDP header 441 can be compressed by the method disclosed in Non-Patent Document 2 and the like. In this case, the file sending device 11 may generate and send the broadcast IP packet 50B shown in FIG. The broadcast IP packet 50B shown in FIG. 6D has a format in which a download header 421 is added to the data unit 401 and a compressed header 461 obtained by compressing the IP / UDP header is added. Hereinafter, the broadcast IP packet 50A and the broadcast IP packet 50B are referred to as a broadcast IP packet 50 unless otherwise distinguished.

(Transmitter)
The transmission device 12 includes a computer including an arithmetic device such as a CPU, a storage device such as a memory and a hard disk, and an interface device that transmits and receives various types of information to and from the outside, a program installed in the computer, and the computer And a digital broadcast transmitter connected to. The transmission device 12 transmits the broadcast IP packet acquired from the file transmission device 11 by a broadcast wave via the broadcast transmission path 30 when the file transmission start time comes.

(Data supplement server)
The data complementing server 13 is installed in a computer including a computing device such as a CPU, a storage device such as a memory and a hard disk, an input / output interface for transmitting and receiving various information to and from the outside, and a communication interface device. Program. The file sending device 11 is realized by the hardware device and software cooperating to control the hardware resources described above by a program. As shown in FIG. Complement request IP packet receiving means 132, division number determining means 133, complement IP packet generating means 134, and complement IP packet transmitting means 135 are provided.

  The file information storage unit 131 stores, for each file transmitted through the broadcast transmission path 30, a specified size of a data unit (file fragment) included in the file, for example, a general memory or a hard disk Etc.

  The complement request IP packet receiving means 132 receives the complement request IP packet 60 including specific information for identifying an unacquired data unit (file fragment) in the received file from the receiving terminal 21 via the communication line 40. To do. In the present embodiment, specific information for specifying an unacquired data unit is used as information in the download header 421. That is, the information specifying the unacquired data unit is Transport File ID 501, Block Number 502, and Sequence Number 503 shown in FIG.

  The division number determining unit 133 extracts the specified size of the unacquired data unit from the file information storage unit 131 based on the information of the download header 421 included in the complement request IP packet 60 received from the receiving terminal 21. A predetermined integer value that defines the extracted specified size is determined as the division number of the data unit. That is, the division number determining unit 133 defines the data unit size when the file of Transport File ID that specifies the missing data unit requested by the complement request IP packet 60 is transmitted from the transmission device 12 via the broadcast transmission path 30. Is extracted and the number of divisions is determined.

  Based on the information of the download header 421 included in the complementary request IP packet 60 received from the receiving terminal 21, the complementary IP packet generating unit 134 sets the unacquired data unit to a predetermined integer value that defines a specified size. The supplemental IP packet 70 is generated by dividing into partial file fragments (part of the requested data unit) having an equal number of data and packetizing. In this embodiment, the complementary IP packet generation unit divides an unacquired data unit by the number of divisions determined by the division number determination unit 133. Further, the complementary IP packet generation unit 134 assigns division order information indicating the position in the requested data unit to the divided partial file fragment (part of the requested data unit). The complementary IP packet transmitting unit 135 transmits the generated complementary IP packet to the receiving terminal 21 via the communication line 40.

  As shown in FIG. 8, the complementary IP packet 70 generated by the complementary IP packet generating means 134 includes a part 601 (partial file fragment) of the generated data unit in the data part, and the header part. A repair header 621 (repair header) is included. Although the illustration of the IP / UDP header is omitted in FIG. 8, the IP / UDP header 441 is arranged in the upper layer of the repair header 621 in FIG. 8.

  The repair header 621 includes identification information for specifying an unacquired file fragment and division order information. Specific information for specifying an unacquired file fragment is information of the download header 421. The division order information is information indicating the position of the partial file fragment in the unacquired file fragment. Specifically, the repair header 621 shown in FIG. 8 is a total 12-byte header including Transport File ID 501, Block Number 502, Sequence Number 503, suffix 641, and Reserved 642 as fields.

  Transport File ID 501, Block Number 502, and Sequence Number 503 are the same as the fields of the download header 421 shown in FIG. The suffix field 641 is a field in which division order information is described. The Reserved field 642 is an extended area for the future. In FIG. 8, if the suffix 641 and the reserved 642 are 4 bytes in total, the number of bits in each field may be arbitrary. Here, a specific example of the division order information in the suffix field 641 when the number of divisions is 3 is shown in FIG.

  As shown in FIG. 9A, it is assumed that the size of the data unit (file fragment) of the broadcast IP packet 50 on the broadcast transmission path 30 is “4032 bytes”. In this case, as shown in FIG. 9B, the size of the data unit of the complementary IP packet 70 on the communication line 40 (part of the data unit of the broadcast IP packet 50, that is, the partial file fragment) is “1344”. Byte ". At this time, in order to indicate the block number and sequence number of the data unit of the broadcast IP packet 50 before division, repair headers 621a, 621b, and 621c are added for each packet. The data units 601a, 601b, and 601c (each part of the original data unit) as partial file fragments obtained by dividing the data unit (file fragment) of the broadcast IP packet 50 are divided into three equal parts and added to the repair header 621a. , 621b and 621c have the same block number and sequence number.

  Furthermore, “suffix = 1” is assigned to the repair header 621a added to the data unit 601a (a part of the original data unit) of the first complementary IP packet. Further, “suffix = 2” is assigned to the repair header 621b added to the data unit 601b (a part of the original data unit) of the second complementing IP packet. Similarly, “suffix = 3” is assigned to the repair header 621c added to the data unit 601c (a part of the original data unit) of the third complementing IP packet. In FIG. 9, the IP / UDP header is not shown in each packet.

(Receiving terminal)
The receiving terminal 21 includes a computer including an arithmetic device such as a CPU, a storage device such as a memory and a hard disk, an input device such as a remote controller, and a communication interface device that transmits and receives various types of information to and from the outside. It consists of an installed program, a tuner that receives digital broadcasts, and a television monitor such as an LCD.

  The receiving terminal 21 is realized by the above hardware resources being controlled by a program through the cooperation of the hardware device and software. As shown in FIG. 5, the broadcast receiving means 211, the file restoring means, 212, loss determination means 213, file storage means 214, complement request IP packet generation means 215, complement request IP packet transmission means 216, complement IP packet reception means 217, complement fragment construction means 218, , A file restoration unit 219, a reproduction unit 220, an operation unit 221, and an output display unit 222.

  The broadcast receiving means 211 is composed of, for example, a tuner, and receives a broadcast IP packet 50 transmitted via the broadcast transmission path 30 as data constituting a content (file). The received broadcast IP packet 50 is output to the file restoration unit 212. The broadcast receiving unit 211 receives the broadcast IP packet 50 transmitted through the broadcast transmission path 30 at a time notified in advance by a program guide or the like.

  The file restoration unit 212 identifies a file to be restored by the Transport File ID 501 of the download header 421 (see FIG. 7) of each broadcast IP packet 50 received by the broadcast reception unit 211. Further, the file restoration unit 212 reconstructs the content (file) as it is by sequentially connecting the data units 401 constituting the target file based on the block number 502 and the sequence number 503 of the download header 421. (Restore). Data obtained by concatenating the data units 401 in order is output to the defect determination unit 213.

  Based on the information in the header part of the received broadcast IP packet 50, the defect determination means 213 concatenates the data units (file fragments) included in each received broadcast IP packet 50 and configures the file as it was. At this time, it is determined whether or not the data unit 401 (file fragment) is missing. This missing discriminating means 213 determines that the broadcast IP packet 50 is not included in the file specified by the Transport File ID 501 of the download header 421 when a numerical value is missing among consecutive integer values of the Sequence Number 503 for each Block Number 502. It is determined that the data unit 401 has been lost. For example, if a packet with a sequence number “2” is lost among packets having consecutive integer values from “1” to “3”, the data unit 401 stored in the corresponding packet is lost. Will be.

  When the data unit 401 is missing, the loss determination unit 213 outputs information of the download header 421 of the corresponding broadcast IP packet 50 to the complement request IP packet generation unit 215. If the data unit 401 is not missing, the missing discrimination means 213 stores the file configured as it is in the file storage means 214. If the data unit 401 is not missing, the missing discrimination means 213 may output the original file to the output display unit 222 via the playback means 220.

  The file accumulating unit 214 accumulates files originally configured, and is composed of, for example, a general hard disk. The file accumulating unit 214 accumulates the files that have been completely and accurately restored by the file restoring unit 212, and accumulates the files supplemented with the missing data by the processing of the file restoring unit 219.

  When the data unit (file fragment) is missing, the complement request IP packet generation unit 215 uses the header of the broadcast IP packet 50 corresponding to the data unit as information for specifying the unacquired data unit. The complement request IP packet 60 including the stored information is generated. In the present embodiment, the complement request IP packet generation unit 215 generates the complement request IP packet 60 when the missing data unit 401 is complemented by receiving the broadcast again and further missing data remains. The generated complement request IP packet 60 is output to the complement request IP packet transmission means 216. The generated complement request IP packet 60 includes, in the header portion, information of the download header 421 of the broadcast IP packet 50 to be complemented, the IP / UDP header having the data complement server 13 as the destination and the receiving terminal 21 as the source. Including. The complement request IP packet 60 includes a message requesting complementation in the data portion.

  The complement request IP packet transmitting means 216 is constituted by a communication interface, for example, and transmits the complement request IP packet 60 generated by the complement request IP packet generating means 215 to the data supplement server 13 via the communication line 40. It is.

  Complementary IP packet receiving means 217 is composed of, for example, a communication interface, and is a predetermined integer value that defines a prescribed size of a data unit (file fragment) per one supplementary request IP packet 60 transmitted to data supplement server 13. As many as (for example, three) complementary IP packets 70 are received from the data complementing server 13 via the communication line 40. The received complementary IP packet 70 is output to the complementary fragment constructing means 218.

  The values of the fields (Transport File ID 501, Block Number 502, and Sequence Number 503) corresponding to the repair header 621 of the complementing IP packet 70 are the values of the fields of the download header 421 included in the complementing request IP packet 60. There are as many complementary IP packets 70 that are all the same as a predetermined integer value (for example, three) that defines the specified size of the requested data unit.

  Complementary fragment constructing means (complementary file fragment constructing means) 218 includes each repair header 621 included in the repair header 621 of a predetermined integer number (for example, three) of complementary IP packets 70 received by the complementary IP packet receiving means 217. Based on the division order information (number) in the suffix field 641, a part 601 (partial file fragment) of the data unit stored in each complementary IP packet 70 is concatenated, and the unacquired data unit 401 is used as a complementary fragment. To build. At this time, the complementary fragment constructing means 218 concatenates a part 601 (partial file fragment) of the data unit in the order of the number in the suffix field 641 to form a data unit having the same sequence number 503. Similarly, a part 601 (partial file fragment) of a data unit whose sequence number 503 is another value is also concatenated. When complementing the target file identified by the same Transport File ID 501 in the unit of the block number 502, the data units 401 in which the block number 502 has the same value and the sequence number 503 continues are connected. To make a complementary fragment. The constructed complementary fragment is output to the file repair means 219.

  The file repair means 219 connects the complementary fragment (data unit) constructed by the complementary fragment construction means 218 to the missing position in the unrestored file. This file restoration means 219 inserts the data unit 401 of the block number 502 and the sequence number 503 of the same target Transport File ID 501 into the missing part of the unrestored file received on the broadcast transmission path 30. As described with reference to FIG. 3B and FIG. 3C, these complementary fragments are data in which a deficiency remains after complementing a deficient data unit by receiving a broadcast again. Connected to region 82. The file to which the complementary fragments are connected is stored in the file storage unit 214.

  The playback unit 220 plays back the content (file) stored in the file storage unit 214 or the content (file) acquired in real time by reception based on an instruction from the operation unit 221 such as a remote controller, and the LCD monitor Or the like on the output display unit 222.

  The receiving terminal 21 uses the file reconstructing unit 212 to connect the broadcast IP packets 50 in order and reconstruct the file as it is. It is also possible to configure such that complementation is requested sequentially every time a missing data unit group is found. In this case, the receiving terminal 21 sequentially repairs the file by the file repair unit 219, so the processing result of the file repair unit 219 is output to the defect determination unit 213. Then, a series of complementing processes are repeated until it is determined by the missing determination means 213 that there is no missing data unit. Even with such a configuration, the integrity of the received file can be ensured.

[Specific examples of IP packets for broadcasting]
As the communication line 40, for example, Ethernet (registered trademark) is used. In Ethernet (registered trademark), the size that can be stored in a MAC frame without dividing a packet to be transmitted is 1500 bytes. Here, assuming that the IPv6 / UDP packet 901 shown in FIG. 11B is transmitted as the broadcast IP packet 50A, in order to secure a data size as large as possible in the data portion 920 (payload), an extension header 913 is used. No (0 bytes). Since the size of the IPv6 header 911 is 40 bytes and the size of the UDP header 912 is 8 bytes, when using Ethernet (registered trademark), the maximum size of the UDP payload (data portion 920) is 1452 bytes. Furthermore, in this embodiment, in order to generate the complementing IP packet 70 in the data complementing server 13, it is necessary to add a 12-byte repair header 621 to the UDP payload. Therefore, 12 bytes further from the maximum size of the UDP payload. Is deducted. As a result, the maximum size that can be transmitted as a part 601 of the data unit stored in the data portion of the complementary IP packet 70 is 1440 bytes. Hereinafter, three examples of the packets constituting the file are shown in order.

(First example: file that is a set of TS with time stamp)
FIG. 10 is a diagram illustrating an example of a broadcast IP packet generated by the file transmission apparatus according to the embodiment of the present invention. In this example, the file generated by the file transmission device 11 is content configured by a TS (Timestamped Transport Stream) with a time stamp. As shown in FIG. 10A, the TS with a time stamp is a set of TS packets 700 with a time stamp of a total of 192 bytes, in which a 4-byte time stamp 720 is added to each 188-byte TS packet 710. The TS with time stamp is defined in “Radio Industry Association,“ Data Broadcast Coding and Transmission System in Digital Broadcasting ”, First Volume, ARIB STD-B.24, 1999”.

  As described above, the maximum size that can be transmitted as the part 601 of the data unit stored in the data part of the complementary IP packet 70 as the IPv6 / UDP packet 901 is 1440 bytes. If eight TS packets 700 with a time stamp of 192 bytes are combined, it becomes 1536 bytes, which exceeds the maximum size that can be transmitted through the communication line 40. Therefore, when a TS with a time stamp is transmitted using the communication line 40, seven time-stamped TS packets 700 are stored in one IP packet and transmitted. In the present embodiment, as an example, the payload size of the broadcast IP packet 50 is three times the payload size of the complementary IP packet 70. For this reason, the size of the data unit 401 stored in the data part of the broadcast IP packet 50 generated by the file sending device 11 and transmitted from the file sending device 11 to the receiving terminal 21 via the broadcast transmission path 30 is represented by ( 192 × 7) × 3 = 4032 bytes. The packet size at this time is schematically shown in FIG.

  10B, reference numerals 601a, 601b, and 601c denote data units (payloads) stored in the data portion (payload) of the complementing IP packet 70 transmitted from the data complementing server 13 to the receiving terminal 21 via the communication line 40. A partial file fragment, a part of the data unit 401). The size of each data unit 601a, 601b, 601c is (192 × 7) = 1344 bytes. In FIG. 10B, a broadcast header IP packet 50A is configured by adding a download header 421 and an IP / UDP header 441 to the data unit 401.

  In this embodiment, for convenience, as shown in FIG. 10C, one block 51 is configured by 65536 broadcast IP packets 50A, and the sequence number in the block is “0 to 65535”. In FIG. 10D, the file 301 is composed of K blocks 51 and the block numbers are “0 to K−1”.

(Second example: file that is a set of TS)
In this example, the file generated by the file sending device 11 is assumed to be content composed of TS (Transport Stream). TS is a set of 188-byte TS packets 710. If eight 188-byte TS packets 710 are combined, it becomes 1504 bytes, which exceeds the maximum size (1440 bytes) that can be transmitted through the communication line 40. Therefore, when TS is transmitted using the communication line 40, seven TS packets 710 are stored in one IP packet and transmitted.

  In the present embodiment, as an example, the payload size of the broadcast IP packet 50 is three times the payload size of the complementary IP packet 70. For this reason, the size of the data unit 401 stored in the data part of the broadcast IP packet 50 generated by the file sending device 11 and transmitted from the file sending device 11 to the receiving terminal 21 via the broadcast transmission path 30 is represented by ( 188 × 7) × 3 = 3948 bytes. In this case, the size of the partial file fragment (part of the data unit) stored in the data portion (payload) of the complementary IP packet 70 is (188 × 7) = 1316 bytes.

(Third example: Files that can be divided into arbitrary sizes)
In this example, the file generated by the file sending device 11 is a file that can be divided into arbitrary sizes. Therefore, when a file that can be divided into an arbitrary size is transmitted through the communication line 40, a file fragment (part 601 of the data unit) of the maximum size (1440 bytes) that can be transmitted through the communication line 40 is stored and transmitted. Further, in the present embodiment, as an example, the payload size of the broadcast IP packet 50 is three times the payload size of the complementary IP packet 70, and therefore the data stored in the data portion of the broadcast IP packet 50 The size of the unit 401 is (1440) × 3 = 4320 bytes.

  According to the present embodiment, the file sending device 11 uses the complementary IP in which the payload size of the broadcast IP packet 50 transmitted through the broadcast transmission path 30 is transmitted from the data supplement server 13 to the receiving terminal 21 through the communication line 40. The broadcast IP packet 50 is generated so as to be larger than the payload size of the packet 70 and an integral multiple thereof. Further, since the data complementing server 13 adds the division order information to the suffix field of the repair header 621 of the plurality of complementing IP packets 70, the receiving terminal 21 that has received the plurality of complementing IP packets 70 is described in the suffix field. By connecting the partial file fragments using the divided order information, the same data unit 401 (complementary fragment) as that transmitted on the broadcast transmission path 30 can be configured. Therefore, the receiving terminal 21 can easily perform complementation by inserting the connected complementing fragment into the missing position. At this time, the missing position can be specified by a download header 421 such as a sequence number added to the broadcast IP packet 50 transmitted through the broadcast transmission path 30. For this reason, it is not necessary to use low-level information such as the byte position of missing information as in the prior art.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment. For example, in the present embodiment, as an example, the payload size of the broadcast IP packet 50 is three times the payload size of the complementary IP packet 70, but is not limited to this. It may be an integer multiple of 4 or more. Table 1 shows an example. For example, in the example of transmitting a file that is a set of 192-byte TTSs as the broadcast IP packet 50, 9408 bytes (1344 × 7), 16128 bytes (1344 × 12), or the like may be used. These sizes should be determined in consideration of the processing capability of the receiving terminal 21 or the network environment from the tuner unit to the receiving application.

  Further, in this embodiment, the complementary IP packet 70 is added with the repair header 621, and then added with the IP / UDP header 441 and transmitted using UDP. However, in addition to UDP, TCP (Transmission Control) It is also possible to respond with Protocol. In this case, after the repair header 621 is added, a response is made as a packet with the TCP header and the IP header added.

  In the present embodiment, the broadcast transmission path 30 is described as an advanced BS transmission path. However, the present invention is not limited to this, and can be used for distribution on a general broadcast transmission path. As a method for transmitting an IP packet using a broadcast transmission path, MPE (Multi Protocol Encapsulation, ETSI EN 301 192), ULE (Unidirectional Lightweight Encapsulation, RFC 4326), and the like are known. Even when these are used, the present invention can be applied. However, in MPE, the upper limit size of an IP packet is 4 KB.

  Moreover, although the data complementing server 13 of this embodiment is provided with the file information storage means 131 and the division | segmentation number determination means 133, these components are not essential. For example, if the content provider 10 fixes the broadcast IP packet 50 transmitted through the broadcast transmission path 30 to a common data size (for example, 4032 bytes) for each content (file), the number of divisions is constant (for example, 3) That is why. When configured in this way, the data complementing server does not need to determine the number of divisions every time it is requested from the receiving terminal 21. In the case where the file information storage unit 131 and the division number determination unit 133 are provided, for example, in the broadcast IP packet 50, the music content has a payload length of 4032 (= 1344 × 3) bytes, video The content has an effect that the broadcast IP packet 50 changed according to the type of the content (file) such as a payload length of 16128 (= 1344 × 12) bytes can be complemented by one data complementing server 13.

It is a block diagram which shows typically the advanced satellite digital broadcasting system containing the file transmission apparatus which concerns on embodiment of this invention, a data supplement server, and a receiving terminal. It is a sequence diagram which shows the operation | movement which complements the data loss occurrence in the advanced satellite digital broadcasting system shown in FIG. It is explanatory drawing of the mode of the data loss in the advanced satellite digital broadcasting system shown in FIG. 1, and the complement. It is a block diagram which shows typically the structure of the file transmission apparatus and data complement server which concern on embodiment of this invention. It is a block diagram which shows typically the structure of the receiving terminal which concerns on embodiment of this invention. It is a figure which shows the structure of the IP packet for a broadcast produced | generated with the file transmission apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the download header added to a data unit in the file transmission apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the repair header added to a data unit in the data complementing server which concerns on embodiment of this invention. It is a figure which shows an example of the IP packet for a broadcast produced | generated with the file transmission apparatus which concerns on embodiment of this invention, and the IP packet for a complementation produced | generated in the data supplement server which concerns on embodiment of this invention. It is a figure which shows an example of the broadcast IP packet produced | generated with the file transmission apparatus which concerns on embodiment of this invention. It is a figure which shows the general structure of an IP packet.

Explanation of symbols

1 Advanced Satellite Digital Broadcasting System 11 File Sending Device (Broadcast Packet Generator)
DESCRIPTION OF SYMBOLS 111 File input means 112 File division means 113 Broadcast packet generation means 114 File storage means 12 Transmission apparatus 13 Data complement server 131 File information storage means 132 Supplement request IP packet reception means 133 Division number determination means 134 Complement IP packet generation means 135 Complementary IP packet transmitting means 21 Receiving terminal 211 Broadcast receiving means 212 File restoration means 213 Loss determination means 214 File storage means 215 Complementation request IP packet generation means 216 Complementation request IP packet transmission means 217 Complementary IP packet reception means 218 Complementary fragment construction means 219 File restoration means 220 Reproduction means 221 Operation part 222 Output display part 30 Broadcast transmission path 31 Artificial satellite 40 Communication line

Claims (8)

A broadcast packet generation device that generates a broadcast IP packet that is distributed via a broadcast transmission path as an IP packet for each file fragment obtained by dividing a file, and a receiving terminal that receives the file transmitted as the broadcast IP packet. The broadcast packet generation in the digital broadcasting system that ensures the integrity of the file received through the broadcast transmission path by acquiring the unacquired file fragment in the received file from the data supplement server via the communication line A device,
For each file, the size of the file fragment is larger than the size of data stored in the data portion of the packet transmitted from the data complementing server to the receiving terminal, and becomes a prescribed size obtained by multiplying the size by a predetermined integer value. File dividing means for dividing the file into
Broadcast packet generating means for generating the broadcast IP packet storing the specific information for specifying the file fragment in order to download the file in the header portion and storing the file fragment in the data portion;
A broadcast packet generation apparatus comprising: Specific information for specifying the file fragment is:
An identifier of a file including the file fragment, a block number indicating a position in the file of a block made up of a plurality of file fragments including the file fragment, and a sequence number indicating a position of the file fragment in the block The broadcast packet generation apparatus according to claim 1, wherein the broadcast packet generation apparatus has a download header. The broadcast packet generating apparatus according to claim 1 or 2 is transmitted as a broadcast IP packet including the specified-size file fragment in a data portion and specifying information identifying the file fragment in a header portion. A data complementing server that transmits a complementing IP packet for complementing the broadcast IP packet to the receiving terminal via a communication line for a receiving terminal that has received the file to be received via the broadcast transmission path,
Complementation request IP packet receiving means for receiving, from the reception terminal, a complementation request IP packet including specific information for identifying an unacquired file fragment in the file;
Based on the specific information for identifying the unacquired file fragment, the unacquired file fragment is divided into partial file fragments of a uniform integer number of data having a predetermined integer value defining the specified size, and the divided The division order information indicating the position in the file fragment is given to the partial file fragment, the specific information for specifying the file fragment and the division order information are stored in the header part to complement the file fragment, and A complementary IP packet generating means for generating the complementary IP packet in which the partial file fragment is stored in the data portion;
Complementary IP packet transmitting means for transmitting the complementary IP packet to the receiving terminal;
A data complementing server comprising: For each file transmitted through the broadcast transmission path, file information storage means for storing a prescribed size of the file fragment included in the file;
Based on the specific information specifying the unacquired file fragment included in the complement request IP packet, the specified size of the unacquired file fragment is extracted from the file information storage means, and the extracted specified size is defined Division number determining means for determining the predetermined integer value as the division number of the file fragment,
The data complementing server according to claim 3, wherein the complementing IP packet generating unit divides the unacquired file fragment by the determined number of divisions. The broadcast packet generating apparatus according to claim 1 or 2 is transmitted as a broadcast IP packet including the specified-size file fragment in a data portion and specifying information identifying the file fragment in a header portion. File is received via a broadcast transmission path, and unacquired file fragments in the received file are acquired from the data complementing server according to claim 3 or 4 as a plurality of complementing IP packets via a communication line. A receiving terminal,
Broadcast receiving means for receiving the broadcast IP packet;
Based on information in the header part of the received broadcast IP packet, it is determined whether the file fragment is missing when the file fragment included in each received broadcast IP packet is connected to restore the file. Deficiency determination means,
When the file fragment is missing, a complementary request IP packet including information stored in the header portion of the broadcast IP packet corresponding to the file fragment is generated as specific information for identifying an unacquired file fragment. A complementary request IP packet generating means for performing,
A complement request IP packet transmitting means for transmitting the generated complement request IP packet to the data complement server;
Complementary IP packet receiving means for receiving, from the data complementing server, the complementing IP packets by a predetermined integer value that defines a prescribed size of the file fragment per one complementing request IP packet;
Complementary file fragment constructing means for constructing the unacquired file fragment by concatenating the partial file fragments in order based on the respective division order information included in each received supplementary IP packet;
A file repairing means for linking the constructed file fragment to a missing position in a file in which the file fragment is missing;
A receiving terminal comprising: A broadcast packet generation device that generates a broadcast IP packet that is distributed via a broadcast transmission path as an IP packet for each file fragment obtained by dividing a file, and a receiving terminal that receives the file transmitted as the broadcast IP packet. In the digital broadcasting system for ensuring the integrity of the file received via the broadcast transmission path by acquiring the unacquired file fragment in the received file from the data complementing server via the communication line, the broadcast IP In order to generate a packet, a computer constituting the broadcast packet generation device,
For each file, the size of the file fragment is larger than the size of data stored in the data portion of the packet transmitted from the data complementing server to the receiving terminal, and becomes a prescribed size obtained by multiplying the size by a predetermined integer value. File dividing means for dividing the file into
Broadcast packet generation means for generating the broadcast IP packet storing the specific information for specifying the file fragment in order to download the file in the header portion and storing the file fragment in the data portion;
A broadcast packet generation program characterized in that it functions as: The broadcast packet generating apparatus according to claim 1 or 2 is transmitted as a broadcast IP packet including the specified-size file fragment in a data portion and specifying information identifying the file fragment in a header portion. In order to transmit a complementary IP packet for complementing the broadcast IP packet to the receiving terminal via a communication line for a receiving terminal that has received the file to be received via the broadcast transmission path,
Complementation request IP packet receiving means for receiving, from the reception terminal, a complementation request IP packet including specific information for identifying an unacquired file fragment in the file;
Based on the specific information for identifying the unacquired file fragment, the unacquired file fragment is divided into partial file fragments of a uniform integer number of data having a predetermined integer value defining the specified size, and the divided The division order information indicating the position in the file fragment is given to the partial file fragment, the specific information for specifying the file fragment and the division order information are stored in the header part to complement the file fragment, and A complementary IP packet generation means for generating the complementary IP packet in which the partial file fragment is stored in the data portion;
Complementary IP packet transmitting means for transmitting the complementary IP packet to the receiving terminal;
Data complementing program characterized by functioning as The broadcast packet generating apparatus according to claim 1 or 2 is transmitted as a broadcast IP packet including the specified-size file fragment in a data portion and specifying information identifying the file fragment in a header portion. File is received via a broadcast transmission path, and unacquired file fragments in the received file are acquired from the data complementing server according to claim 3 or 4 as a plurality of complementing IP packets via a communication line. In order to do so, a computer of a receiving terminal provided with broadcast receiving means for receiving the broadcast IP packet,
Based on information in the header part of the received broadcast IP packet, it is determined whether the file fragment is missing when the file fragment included in each received broadcast IP packet is connected to restore the file. Deficiency discrimination means,
When the file fragment is missing, a complementary request IP packet including information stored in the header portion of the broadcast IP packet corresponding to the file fragment is generated as specific information for identifying an unacquired file fragment. Complement request IP packet generation means
A complement request IP packet transmitting means for transmitting the generated complement request IP packet to the data complement server;
Complementary IP packet receiving means for receiving, from the data complementing server, the complementing IP packets by a predetermined integer value that defines the prescribed size of the file fragment per one complementing request IP packet;
Complementary file fragment constructing means for constructing the unacquired file fragment by concatenating the partial file fragments in order based on the respective division order information included in the received complementary IP packets.
A file repairing means for linking the constructed file fragment to a missing position in a file in which the file fragment is missing;
A file receiving program characterized by functioning as:

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