JP4113743B2 - Parity check method and broadcast distribution network system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a parity check method and a broadcast distribution network system for achieving both reliability and scalability in a broadcast distribution network system using broadcasting and IP multicast.
[0002]
[Prior art]
In recent years, broadband communication has made it possible to use always-on connections, lower charges, and flat-rate services so that large-capacity content such as movies can be used. In addition, the possibility of broadcast-type broadcast communications has become a reality through broadbandization, and streaming such as playback while receiving content, and even partial live distribution is now possible.
[0003]
As broadcast delivery services using broadband, a relay network method using a cache / buffering technique, a content delivery dedicated network method, and an IP multicast method using a broadcast digital communication network are being studied.
[0004]
In the relay network method, a huge server is prepared and content is distributed from there to each user terminal via the Internet. However, there is a limit to the capacity of the server, and when access to the server is concentrated, a heavy load is placed on the network. There are problems such as adding.
[0005]
In addition, the content distribution dedicated network method is a method in which a number of edge servers are arranged on a CDN (content delivery network) prepared by a content distributor and the contents are distributed from each edge server to each user terminal. There are problems such as the cost of distributed arrangement of the server and the fact that the edge server is arranged mainly in a large city and the use in the region is not promoted.
[0006]
The IP multicast method uses IP (Internet Protocol) as a protocol to transmit one data from a distribution source to many routers over the Internet, and copies the data received by each router to each user terminal. Because a broadcast digital communication network is used, large-scale broadcast distribution is possible, but communication between routers is not possible simply by receiving data from the distribution source, and transmission at each router The problem is that the bandwidth is not uniform and must be adjusted to the narrowest bandwidth when delivering to all routers, and if the received data is missing when complemented through the network, the network will be overloaded. There is a point. Further, since it is difficult to ensure reliability by retransmission in a broadcast digital communication network, an error correction code is added to transmission data (contents and the like) in advance to ensure reliability. However, when this broadcast digital communication is used, it is difficult to achieve both the reliability of communication and the scalability of communication scale.
[0007]
[Problems to be solved by the invention]
Thus, IP multicast is advantageous for large-scale broadcast distribution using broadband, but some of the problems can be solved by performing transmission to the provider using radio waves. In other words, content is transmitted from the transmission source by radio waves, and this is received by a number of routers connected to the Internet and distributed to the user terminals, so that the problem between routers and the problem of transmission bandwidth can be solved. Although it can be ensured, if the response to the case where the received data is missing is performed through the network, there still remains a problem that a great load is applied to the network. In the case of large-scale broadcast delivery, ensuring scalability is a very important issue, but as the scale increases, it becomes more difficult to ensure the reliability of complementing received data.
[0008]
The present invention solves such a conventional problem, and a first object thereof is to provide a parity check method and a broadcast distribution network system capable of achieving both reliability and scalability in IP multicast. It is.
[0009]
The second object of the present invention is to make the scalability of the entire Internet level and the reliability secured in the current Internet compatible in the broadcast digital communication.
[0010]
A third object of the present invention is to ensure reliability without adding an error correction code to transmission data in advance, and to uniformly improve the data transfer capacity in the broadcast digital communication band.
[0014]
[Means for Solving the Problems]
  The broadcast distribution network system of the present invention includes:
A transmitting station that transmits content data by radio waves, a plurality of receiving sites connected to a network that receive the radio waves, and a user terminal that receives the content data from the receiving site, wherein the transmitting station transmits the transmission data Content dataThe givenEncoding using a parity check method, and the receiving site receives the received content dataThe givenDecode using parity check methodAt the same time, when all of the receiving sites fail to receive the content data, the receiving site with the fastest line speed receives the complementary data from the transmitting station through the network and transmits it to the other receiving sites.It is characterized by this. By adopting such a configuration, when data is lost, it can be restored with a high probability, and both reliability and scalability can be achieved.Also, for example, if all receiving sites are temporarily unable to receive due to radio interference, the fastest receiving site immediately goes to the transmitting station to collect the data and distributes the data to each receiving site. Therefore, network congestion in the event of a deficiency in the network can be avoided, and both system reliability and scalability can be achieved.
[0015]
Also, the broadcast distribution network system of the present invention includes a transmitting station that transmits content data by radio waves, a plurality of receiving sites that are connected to each other to receive the radio waves, and a user that receives the content data from the receiving sites. A receiving site that has failed to receive content data from the transmitting station, and receives a portion of the data that has failed to be received from another receiving site that has successfully received the content data. Is. With such a configuration, when data is lost, the data can be easily complemented, and both system reliability and scalability can be achieved.
[0016]
Also, the broadcast distribution network system of the present invention includes a transmitting station that transmits content data by radio waves, a plurality of receiving sites that are connected to each other to receive the radio waves, and a user that receives the content data from the receiving sites. A receiving site connected to the network and instructing each receiving site to specify a receiving site as a connection destination, and the receiving site that failed to receive content data from the transmitting station The data of the part that has failed to be received is received from the receiving site of the connection destination instructed by the support server. With such a configuration, when data is lost, the data can be easily complemented, and both system reliability and scalability can be achieved.
[0017]
The broadcast distribution network system of the present invention is characterized in that each receiving site notifies its own line speed information or communication performance to other receiving sites. With this configuration, each receiving site can select several receiving sites with high line speeds from the line speed information received from other receiving sites, and receive missing data from them. Since restoration can be performed quickly, the reliability and scalability of the system can be further improved.
[0018]
Also, in the broadcast distribution network system of the present invention, the transmitting station encodes the content data to be transmitted using the parity check method described above, and a receiving site capable of receiving complementary data from other receiving sites, The content data received from the transmitting station is decoded using the parity check method described above. By performing such parity check and mutual complementation of missing data, if data is missing, it can be restored with a high probability and data can be easily complemented. And scalability can be achieved.
[0019]
Further, in the broadcast distribution network system of the present invention, when all of the receiving sites fail to receive the content data, the receiving site with the fastest line speed receives complementary data from the transmitting station through the network, It is characterized by transmitting to another receiving site. With this configuration, for example, if all receiving sites are temporarily unavailable due to radio interference, the fastest receiving site immediately goes to the transmitting station to collect the data and receives the data. Since it is distributed to the site, it is possible to avoid network congestion when data is lost, and to achieve both system reliability and scalability.
[0020]
In the broadcast distribution network system of the present invention, the destination information is added to the supplementary data so that the receiving site having the fastest line speed transfers the supplementary data from another receiving site to another receiving site. It is characterized by being attached. With this configuration, complementary data can be transferred to all receiving sites in a shorter time.
[0021]
The present invention is a program in which the parity check method described above is described in a form usable by a computer, and the present invention can be easily implemented at all receiving sites.
[0022]
Further, the present invention is a recording medium in which the above-described program is recorded in a computer-readable form, and the present invention can be easily implemented at all receiving sites.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 shows an example of a data configuration for explaining the parity check method according to Embodiment 1 of the present invention, and here shows a case where data to be transmitted is composed of 12 data blocks (packets). . In FIG. 1, parity blocks P1, P2, P3, and P4 are arranged at predetermined positions on a diagonal line from the upper right corner to the lower left corner in a grid having the same number of rows and columns of 4 rows and 4 columns. Data blocks D1 to D12 are arranged in order from left to right in each row from the first row to the lower row, and each parity block P1 to P4 arranged at a predetermined position is data in the row and column to which the respective parity block belongs. The parity check is set for the block. That is, the redundancy code for the data blocks D1, D2, D3, D6, D9, and D12 is stored in P1, and the redundancy code for the data blocks D3, D4, D5, D6, D8, and D11 is stored in P2. P3 stores redundancy codes for data blocks D2, D5, D7, D8, D9, and D10, and P4 stores redundancy codes for data blocks D1, D4, D7, D10, D11, and D12. Has been. As a result, each data block is subjected to a parity check twice by different parity blocks. All blocks are the same size, and it is assumed that other data will not enter, that the data is correct, and that when there is no data, it can be recognized that it has been lost, and the parity is calculated by XOR. It shall be. The transmission data is encoded according to the above rules.
[0024]
Next, decoding when receiving transmission data encoded in this way will be described. First, an example where data restoration is successful will be described.
Case 1: When reception of the data block D7 fails, as shown in FIG. 2, since the redundancy codes for the data blocks D1, D4, D7, D10, D11, and D12 are stored in P4, D7 is set. By calculating D1, D4, D10, D11, and D12 excluding D7, D7 can be restored.
Case 2: If reception of the parity block P2 fails, the data itself is not lost and is ignored.
Case 3: When reception of the data blocks D5, D9, and D11 fails, as shown in FIG. 3, D11 is first restored from P4 and D1, D4, D7, D10, and D12, and then P1 and D1, D9 is restored from D2, D3, D6, and D12, and then D5 is restored from P2, D3, D4, D6, D8, and D11.
Case 4: If reception of the data blocks D1, D2, D3, and P1 fails, as shown in FIG. 4, D11 is first restored from P4 and D4, D7, D10, D11, and D12, and then P3 and D2 is restored from D5, D7, D8, D9, and D10, and then D3 is restored from P2, D4, D5, D6, D8, and D11. P1 is ignored because the data itself is not lost.
[0025]
Next, an example when data restoration fails will be described.
Case 1: If more data blocks than the number of parity blocks are lost, they cannot be restored.
Case 2: Since each data block is always a component of two parity blocks, if two data blocks that are components of the same two parity blocks are lost, for example, as shown in FIG. If D5 and D8 are lost, neither P2 nor P3 can be restored.
Case 3: When other parity blocks cannot be restored and two or more data blocks that are components of a certain parity block are lost, for example, as shown in FIG. 6, D8 that is a component of P3 If two of D9 and D9, two of D8 and D11 that are constituent elements of P2, and two of D9 and D12 that are constituent elements of P1 are lost, they cannot be restored.
Case 4: When two parity blocks having a data block as a constituent element are lost at the same time and the data block is lost, for example, as shown in FIG. 7, D7 which is a constituent element of P3 and P4 is lost. If P3 and P4 are lost at the same time, they cannot be restored.
[0026]
As described above, according to the parity check method in the first embodiment, the data blocks are arranged in a grid having the same number of rows and columns so that one data block becomes a component of two different parity blocks. Therefore, the lost data can be recovered with a high probability except in special cases. Further, by arranging the data constituting each data block as shown in FIG. 1, that is, D1 to D12 in FIG. 1 are arranged as individual data, and one data block is configured as a whole. In this case, two-stage parity check can be performed on the data and the data block that is a set of the data, and more accurate data restoration can be performed.
[0027]
In the first embodiment, a 4-by-4 grid structure is used. However, if the number of rows and columns is the same, the number is arbitrary. In either case, the number of parity blocks is the same as the number of rows and columns. Become.
[0028]
(Embodiment 2)
Next, a broadcast distribution network system according to Embodiment 2 of the present invention will be described with reference to FIG. In FIG. 8, a transmitting station 1 operated or outsourced by a content distributor has an Internet router 2 connected to the Internet 10 as a wide area network, a transmitting device 3 for transmitting content data, and an antenna 4 for transmitting radio waves. The transmission device 3 includes a redundant encoder 5. The redundant encoder 5 performs error correction coding on transmission data by executing the parity check method described in the first embodiment. The transmitting station 1 corresponds to a facility capable of transmitting data by a method such as terrestrial digital broadcasting or digital satellite broadcasting. The receiving site 20 that receives content data from the transmitting station 1 and distributes it to the user receives a receiving device 22 that receives the radio wave from the transmitting station 1 via the antenna 21 and a relay that distributes the received content data to the user terminal 30. A computer 23 and an Internet router 24 connected to the Internet 10 are provided. The receiving site 20 includes a plurality of receiving sites, for example, about 100 to 10000000, which are arranged with a predetermined zone configuration within the range where the radio waves of the transmitting station 1 can reach. A redundancy decoder 25 is provided for performing error correction decoding on received data by executing the parity check method described above. The user terminal 30 is connected to a plurality of terminals 31 (personal computers) receiving distribution of content data from the relay computer 23 through the LAN 32. Instead of this LAN, another dedicated line or the Internet 10 may be used, or a CDN may be used.
[0029]
Next, the operation of the broadcast distribution network system in the second embodiment will be described. Content data is simultaneously delivered from the transmitting station 1 to each receiving site 20 according to an address (eg, IP address) by a broadcast delivery method (for example, IP multicast), and each reception received in a peer-to-peer connection via the Internet 10 The site 20 distributes the received content data to the user terminals 30 belonging to each receiving site 20. The content data transmitted from the transmitting station 1 is transmitted from the transmitting device 3 through the antenna 4 as a packet error-corrected and encoded by the redundancy encoder 5 according to the method described in the first embodiment. The receiving device 22 of the receiving site 20 that has received this radio wave through the antenna 21 is similarly error-corrected and decoded by the redundancy decoder 25 by the method described in the first embodiment, and passed to the relay computer 23. The relay computer 23 distributes content data to each terminal 31 of the user terminal 30 via the LAN 32.
[0030]
As described above, according to the second embodiment, the content data transmitted from the transmitting station 1 is subjected to highly efficient error correction coding by the redundant encoder 5, and the content data received at the receiving site 20 is made redundant. Since highly efficient error correction decoding is performed by the decoder 25, a broadcast delivery method based on a low-reliability and low-load protocol called UDP is used, and wireless communication with more errors than terrestrial wired communication is used. Reliability can be ensured, and reliability can be improved while ensuring scalability by combining broadcast delivery methods such as radio and IP multicast.
[0031]
(Embodiment 3)
Next, a third embodiment of the present invention will be described. FIG. 9 shows the configuration of the broadcast distribution network system in the third embodiment. The third embodiment is different from the second embodiment shown in FIG. 8 in that the transmission device 3 of the transmission station 1 includes a normal encoder, and the reception device 22 of the reception site 20 also includes a normal decoder. And that the relay computer 23 includes the complementary data transmission / reception unit 26, and other configurations are the same as those shown in FIG.
[0032]
In the third embodiment, when the restoration of content data from the transmitting station 1 by the decoder of the receiving device 22 partially fails at each receiving site 20, the relay computer 23 is the minimum necessary for restoring the data. The data is calculated, about 10 receiving sites are obtained from the addresses with random numbers, and the complementary data transmitting / receiving unit 26 requests transmission of missing data to one of the addresses via the Internet 10. When there are some missing data, it is divided into a plurality of addresses or requested in duplicate. If the receiving site 20 that has received the request has successfully received the missing data portion, the receiving site 20 sends the missing data to the complementary data transmitting / receiving unit 26 of the receiving site 20 that sent the request via the Internet 10. If reception has failed, notify that fact. The relay computer 23 that has received the transmission of the complementary data embeds the received data in the missing portion and transmits it to the user terminal 30. Even if the receiving site 20 that has received the request does not hold the missing data at that time, if the missing data is acquired later, the data is transmitted. In addition, each receiving site 20 that has received the request responds by adding its own line speed information or communication performance status when responding.
[0033]
As described above, according to the third embodiment, even when the transmitting station 1 and the receiving site 20 perform error correction using a normal encoder / decoder, the receiving sites 20 complement each other with missing portion data. Therefore, reliability can be improved while ensuring scalability by combining broadcast delivery methods such as radio and IP multicast. In addition, each receiving site 20 can know which receiving site is performing peer-to-peer communication well by exchanging its own line speed information and communication status, and select a good communication partner. Can communicate.
[0034]
(Embodiment 4)
Next, a fourth embodiment of the present invention will be described. In the third embodiment, when the number of receiving sites 20 is small, each receiving site 20 is peer-to-peer-connected, and therefore, by transmitting the missing data individually to the other receiving sites 20 by the above method. However, if the number of receiving sites 20 is large, it may take too long. Therefore, when the number of receiving sites 20 is large, the method of the fourth embodiment is used. FIG. 10 shows the configuration of the broadcast distribution network system according to the fourth embodiment of the present invention, which has a configuration in which an interconnection support server 40 is added to the configuration shown in FIG. The interconnection support server 40 includes an Internet router 41 and a server computer 42 connected to the Internet 10.
[0035]
In the fourth embodiment, each receiving site 20 first notifies the interconnection support server 40 of its own address and the communication band connected to the Internet 10, that is, the line speed. The addresses and communication bands are stored in the server computer 42 as a list, and the addresses of a plurality of connection destination receiving sites 20 having good compatibility are designated for each receiving site 20 from the communication band and the like. The complementary data transmitting / receiving unit 26 of each receiving site 20 stores the addresses of a plurality of connection destination receiving sites 20 received from the interconnection support server 40. When the restoration of the content data received from the transmitting station 1 partially fails at each receiving site 20, the relay computer 23 at each receiving site 20 calculates what is the minimum data necessary for restoring the data, The transmission of the missing data is requested to the connection destination address stored in the complementary data transmitting / receiving unit 26 through the Internet 10. When there are some missing data, the request is divided into a plurality of connection destination addresses or duplicated. If the receiving site 20 that has received the request has successfully received the missing data portion, the receiving site 20 sends the missing data to the complementary data transmitting / receiving unit 26 of the receiving site 20 that sent the request via the Internet 10. The received relay computer 23 embeds the received data in the missing part and transmits it to the user terminal 30. If the receiving site 20 that has received the request has failed to receive the missing data portion, the receiving site 20 that has issued the request is notified. The receiving site 20 that has received the missing data and successfully restored the data reports the fact to the interconnection support server 40. The interconnection support server 40 can dynamically change the designation of the connection destination receiving site by collecting the successful results of such mutual complementation.
[0036]
As described above, according to the fourth embodiment, even when the transmitting station 1 and the receiving site 20 perform error correction using a normal encoder and decoder, the compatibility indicated by each receiving site 20 to the interconnection support server 40. Since the supplemental data of the missing part is requested from the receiving site having a good connection destination, the missing data can be complemented efficiently. In the fourth embodiment, the interconnection support server 40 is an independent server connected to the Internet 10. However, the interconnection support server 40 may be provided in the transmission station 1.
[0037]
(Embodiment 5)
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, as shown in FIG. 11, the second embodiment shown in FIG. 8 and the third embodiment shown in FIG. 9 are combined. That is, in each receiving site 20, when the restoration of the content data by the redundancy decoder 25 partially fails, the complementary data transmitting / receiving unit 26 of the receiving device site 20 transmits the data of the missing part to another receiving site. 20 is requested through the Internet 10. If the receiving site 20 that has received the request has successfully received the missing data portion, the receiving site 20 sends the missing data to the complementary data transmitting / receiving unit 26 of the receiving site 20 that sent the request via the Internet 10. The received relay computer 23 embeds the received data in the missing part and transmits it to the user terminal 30.
[0038]
By combining such data restoration by the redundancy decoder 25 and data mutual complementation by the complementary data transmission / reception unit 26, it is possible to efficiently restore data that cannot be restored by the redundancy decoder 25 alone.
Case 1: When the data D1, D2, D3, P1, and D4 are lost among the content data received from the transmitting station 1, D2 is first restored from P3 by the redundancy decoder as shown in FIG. Next, D4 is restored by mutual complementation, then D1 is restored from P4 by the redundancy decoder, and D3 is restored from P2 by the redundancy decoder.
Case 2: In the content data received from the transmitting station 1, as shown in FIG. 13, when data D5 and D8 are lost, D5 is first restored by mutual complementing, and then D8 is restored by the redundancy decoder. Restore from P2.
Case 3: If the data D8, D9, D11, and D12 are lost among the content data received from the transmitting station 1, as shown in FIG. 14, D8 is first restored by mutual complement, and then D9 is restored. The redundancy decoder restores P3, then D11 is restored from P2 by the redundancy decoder, and D12 is restored from P4 by the redundancy decoder.
Case 4: Among the content data received from the transmitting station 1, as shown in FIG. 15, when data D7, P3, and P4 are lost, D7 is first restored by mutual complement, and P3 and P4 are parity. ignore.
[0039]
As described above, according to the fifth embodiment, by combining data restoration by the redundancy decoder 25 and data mutual complementation by the complementary data transmitting / receiving unit 26, data restoration that cannot be restored only by the redundancy decoder 25 is performed. Can also be performed efficiently. Compared to the case where data reliability is ensured only by parity check from the beginning, the data in the transmitted data is restored by first restoring the data by parity check and restoring the missing part by mutual complement. The amount of data that can be transmitted can be increased by increasing the proportion of the portion. In addition, as a result of increasing the reliability, the time required for data transmission can be shortened as compared with the conventional carousel transfer method or the like.
[0040]
(Embodiment 6)
Next, a sixth embodiment of the present invention will be described. In the fifth embodiment, as shown in FIG. 16, the second embodiment shown in FIG. 8 and the fourth embodiment shown in FIG. 10 are combined. That is, in each receiving site 20, when the restoration of the content data by the redundancy decoder 25 partially fails, the complementary data transmitting / receiving unit 26 of the receiving device site 20 receives the receiving site 20 instructed by the interconnection support server 40. The transmission of the data of the missing part is requested through the Internet 10. If the receiving site 20 that has received the request has successfully received the missing data portion, the receiving site 20 sends the missing data to the complementary data transmitting / receiving unit 26 of the receiving site 20 that sent the request via the Internet 10. The received relay computer 23 embeds the received data in the missing part and transmits it to the user terminal 30.
[0041]
As described above, according to the sixth embodiment, by combining data restoration by the redundancy decoder 25 and data mutual complementation by the complementary data transmitting / receiving unit 26, data restoration that cannot be restored only by the redundancy decoder 25 is performed. Can also be performed efficiently. In addition, since each receiving site 20 requests complementary data for the missing part from the receiving site of the compatible connection instructed by the interconnection support server 40, the missing data can be efficiently supplemented. it can.
[0042]
(Embodiment 7)
Next, a seventh embodiment of the present invention will be described. In the above-described third embodiment, when a request for complementary data is made to another receiving site 20 but cannot be received from any receiving site 20, for example, transmission troubles or weather conditions of the transmitting station 1 The seventh embodiment is suitable when radio wave interference occurs and all the receiving sites 20 temporarily cannot receive radio waves from the transmitting station 1. Each receiving site 20 acquires the line speed information of the other receiving site 20 from the communication results with the other receiving sites 20, and the receiving site 20 with the fastest line speed is selected as the emergency receiving site from the speed information. The If a simultaneous multiple generation wave failure occurs, first try to mutually complement the data as in the third embodiment, and if it is unsuccessful and recognizes that it is a simultaneous multiple generation wave failure, it will be selected in advance. The emergency reception site supplementary data transmission / reception unit 26 that has been sent goes to the transmission device 3 of the transmission station 1 via the Internet 10 to retrieve the supplementary data, and distributes the acquired missing data to the other reception sites 20.
[0043]
As described above, according to the seventh embodiment, even when all receiving sites 20 have received reception failures all at once, the receiving site with the fastest line speed goes through the Internet 10 to obtain complementary data from the transmitting station. Therefore, it is possible to restore the complementary data as quickly as possible without avoiding concentration of access and placing a heavy load on the network. Note that the supplementary data from the emergency receiving site is not sent to all receiving sites, but sent to a receiving site and forwarded from that receiving site to another receiving site. If the supplementary data is sent with the distribution destination list attached, transmission to all receiving sites can be completed in a shorter time. Further, by dividing the data to be transmitted and transmitting it to each receiving site and assembling it at the receiving site, the transmission to all receiving sites can be completed in a shorter time. The receiving site that has received the supplemental data reports the fact to the receiving site of the transmission destination after the reception is completed.
[0044]
(Embodiment 8)
Next, an eighth embodiment of the present invention will be described. Although the eighth embodiment is a system including the interconnection support server 40 as in the fourth and sixth embodiments, the supplementary data is requested to the other receiving sites 20 in the system. First, it is applied to the case where reception is not possible from any receiving site 20 due to simultaneous multiple power generation wave failures or the like. Based on the line speed information acquired from each receiving site 20, the interconnection support server 40 selects the receiving site 20 having the fastest line speed in advance and designates the receiving site as the emergency receiving site, and the distribution destination receiving site is selected. Pass the address. When a simultaneous multi-generation wave failure occurs, first, as in the above-described fourth or sixth embodiment, the simultaneous multi-generation wave failure is attempted by attempting to complement each other either spontaneously or according to an instruction from the interconnection support server 40. And that is notified to the interconnection support server 40. Upon receiving the notification, the interconnection support server 40 instructs the emergency receiving site designated in advance to go to the transmitting device 3 of the transmitting station 1 via the Internet 10 to obtain complementary data. As a result, the supplementary data transmitting / receiving unit 26 of the emergency receiving site goes to the transmitting station 1 to collect the missing data, and distributes the acquired missing data to the necessary receiving site 20 based on the distribution destination list received in advance.
[0045]
In the eighth embodiment, the emergency receiving site may receive the distribution destination list from the transmitting station 1 instead of from the interconnection support server 40. Further, the supplementary data is transmitted from the emergency receiving site, not to all the receiving sites in the distribution destination list, as in the seventh embodiment, but to the receiving site and from the receiving site. A delivery destination list including transfer information may be created so as to be sent to another receiving site. Also, the data to be transmitted may be divided and transmitted to each receiving site, and assembled at the received receiving site. The receiving site that has received the supplemental data reports the fact to the destination receiving site after the reception is completed, and the emergency receiving site that is the final destination sends the supplementary data transfer result to the interconnection support server 40. Report.
[0046]
As described above, according to the eighth embodiment, even when all the reception sites 20 cause reception failures at the same time, the reception site with the fastest line speed goes through the Internet 10 to obtain complementary data from the transmission station. Therefore, it is possible to restore the complementary data as quickly as possible without avoiding concentration of access and placing a heavy load on the network.
[0047]
In the second to eighth embodiments, the transmitting station 1 transmits the terrestrial broadcasting radio wave. However, the broadcasting radio wave may be transmitted using a satellite. It may be sent to a network capable of broadcast distribution via a LAN or a small network. Further, although the Internet 10 is used as a network, other networks such as a hot spot, a local limited network such as a LAN may be used.
[0048]
【The invention's effect】
As described above, according to the parity check method of the present invention, each data block constituting the data block sequence is a component of two different parity blocks. Therefore, when one data block is lost, Even when data cannot be restored with a parity block, data can be restored with the other parity block, and data can be restored with high efficiency as a whole.
For this reason, since only the time and bandwidth for sending data once are required, it is possible to save the use of the broadcast digital communication network.
[0049]
Also, the broadcast distribution network system of the present invention receives content data from a transmitting station that transmits content data by radio waves, a plurality of receiving sites that are connected to the network that receive radio waves from the transmitting station, and a receiving site. Another receiving site that has a user terminal and has received the content data successfully when the receiving site corrects the content data to be transmitted using the parity check method described above or fails to receive the content data from the transmitting station. From the receiving site specified by the interconnection support server connected to the same network, the receiving site that failed to receive the data of the part that failed to receive the content data or received the supplementary data Or all of the receiving sites receive content data In case of failure, the receiving site with the fastest line speed receives supplementary data from the transmitting station through the network and transmits it to other receiving sites. Reliability can be ensured even if a delivery method and wireless communication are combined, and both reliability and scalability can be achieved.
[Brief description of the drawings]
FIG. 1 is a data configuration diagram for explaining a parity check method according to Embodiment 1 of the present invention;
FIG. 2 is a data configuration diagram illustrating a method for restoring missing data by a parity check method according to the first embodiment of the present invention.
FIG. 3 is a data configuration diagram illustrating a method for restoring missing data by the parity check method according to the first embodiment of the present invention.
FIG. 4 is a data configuration diagram illustrating a method for restoring missing data by a parity check method according to the first embodiment of the present invention.
FIG. 5 is a data configuration diagram illustrating a method for restoring missing data by the parity check method according to the first embodiment of the present invention.
FIG. 6 is a data configuration diagram illustrating a method for restoring missing data by the parity check method according to the first embodiment of the present invention.
FIG. 7 is a data configuration diagram illustrating a method for restoring missing data by a parity check method according to the first embodiment of the present invention.
FIG. 8 is a system configuration diagram of a broadcast distribution network system according to a second embodiment of the present invention.
FIG. 9 is a system configuration diagram of a broadcast distribution network system according to a third embodiment of the present invention.
FIG. 10 is a system configuration diagram of a broadcast distribution network system according to a fourth embodiment of the present invention.
FIG. 11 is a system configuration diagram of a broadcast distribution network system according to a fifth embodiment of the present invention.
FIG. 12 is a data configuration diagram for explaining a method for restoring missing data by mutual complementation between a redundant decoder and a receiving site according to the fifth embodiment of the present invention.
FIG. 13 is a data configuration diagram for explaining a method for restoring missing data by mutual complementation between a redundant decoder and a receiving site according to the fifth embodiment of the present invention.
FIG. 14 is a data configuration diagram for explaining a method for restoring missing data by mutual complementation between a redundant decoder and a receiving site according to the fifth embodiment of the present invention.
FIG. 15 is a data configuration diagram for explaining a method for restoring missing data by mutual complementation between a redundant decoder and a receiving site according to the fifth embodiment of the present invention.
FIG. 16 is a system configuration diagram of a broadcast distribution network system according to a sixth embodiment of the present invention.
[Explanation of symbols]
1 Transmitting station
2 Internet router
3 Transmitter
4 Antenna
5 Redundant encoder
10 Internet
20 Receiving site
21 Antenna
22 Receiver
23 Relay computer
24 Internet router
25 Redundant decoder
26 Complementary data transmitter / receiver
30 User terminal
31 terminals
32 LAN
40 Interconnection support server
41 Internet router
42 Server computer

Claims (6)

A transmitting station for transmitting content data by radio waves, a plurality of receiving sites connected to each other for receiving the radio waves, and a user terminal for receiving the content data from the receiving site,
The transmitting station sets the content data to be transmitted in a grid having the same number of rows and columns in the vertical and horizontal directions, with each of the squares on the diagonal line from the upper corner to the lower corner being a predetermined position of the parity block, and the upper row. Data blocks are arranged in order in each row from the first row to the lower row, and each parity block arranged at the predetermined position performs a parity check on the data blocks in the row and column to which the respective parity block belongs. A redundant encoder that encodes using a check method, and
The receiving site sets the received content data in a grid having the same number of rows and columns in the vertical and horizontal directions, with each of the squares on the diagonal line from the upper corner to the lower corner being a predetermined position of the parity block. Data blocks are arranged in order in each row from the first row to the lower row, and each parity block arranged at the predetermined position performs a parity check on the data blocks in the row and column to which the respective parity block belongs. broadcasting network system, wherein and this with a redundant decoder you decode by using the check method. The reception site includes a complementary data transmission / reception unit that receives and supplements the data of the failed missing part from another reception site when the restoration of content data by the redundancy decoder partially fails. The broadcast distribution network system according to claim 1. An interconnection support server connected to the network and instructing each receiving site to connect to a receiving site;
When the restoration of the content data by the redundancy decoder partially fails, the complementary data transmitting / receiving unit receives the data of the failed missing part from the connection destination receiving site designated by the interconnection support server. The broadcast distribution network system according to claim 1 or 2, wherein the broadcast distribution network system is supplemented . The reception site, when the content data restoration by the redundancy decoder has partially failed, the data of the failed missing part could not be received from other reception sites,
Broadcasting network system according to any one of claims 1 to 3, characterized in that the fastest receiving site line speed is complemented by receiving data of the defective portion from the transmitting station via the network. Claims the fastest reception site line speed, as further transfers data in the defect portion to the other receive sites from other receiving site, characterized in that to attach the distribution destination information to the data of the lost portion Item 5. The broadcast distribution network system according to item 4 . Each receiving site notifies its own line speed information or communication performance to another receiving site or the interconnection support server, and the receiving site or the interconnection support server connects the line based on the line speed information or communication performance. broadcasting network system according to any one of claims 3 to 5, characterized in that selects the fastest reception site speed.

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