JP4605479B2 - Transmission device and transmission method, reception device and reception method, transmission / reception system, and transmission / reception method - Google Patents

Description

  The present invention relates to a transmission device and a transmission method, a reception device and a reception method, and a transmission / reception system and a transmission / reception method. In particular, for example, when distributing data to a large number of databases in a distributed database, The present invention relates to a transmission device and a transmission method, a reception device and a reception method, a transmission / reception system, and a transmission / reception method suitable for distributing data by multicast and for distributing other data to an unspecified number.

  Various methods have been proposed as a data distribution method. For example, the current Internet is based on TCP / IP (Transmission Control Protocol / Internet Protocol) such as HTTP (Hyper Text Transfer Protocol). Protocol is adopted. In TCP / IP, a call is made from a receiving side receiving data distribution to a data transmitting side, and a connection is established between the transmitting side and the receiving side every time data is transmitted / received. Since it is established, highly reliable data distribution can be performed. However, on the other hand, the load on the transmission side and the network increases, and it may be difficult to perform efficient data distribution.

  In other words, if the number of terminals that receive data increases and access to the server that provides data is concentrated, a large load is placed on the server and the network. It sometimes took time.

  Therefore, a method has been proposed in which data is distributed using, for example, a satellite line or a CATV network capable of simultaneous broadcasting over a wide area. In this case, the load on the server and the network is not affected by the increase in the number of terminals.

  By the way, when data is distributed using a satellite line or the like, on the receiving side, the desired data is broadcast on which channel (in the case of a satellite line, which transponder, which frequency band), and when it is broadcast. Since it is not known whether it will be received or not, it is necessary to constantly monitor all channels, which increases the burden on the receiving side.

  The present invention has been made in view of such a situation, and makes it possible to perform efficient data distribution while suppressing an increase in burden on the receiving side.

A receiving apparatus according to an aspect of the present invention includes: a receiving unit that receives content data of a broadcast program repeatedly transmitted by a data carousel method; and an event message for receiving the content data; storage means for storing the content data, contained in the event message received by the receiving means, detecting means for detecting the broadcast schedule information for receiving the content data, the reception start time of the content data Determining means for determining with reference to a broadcast time included in the broadcast schedule information detected by the detection means; and a time at which the broadcast time included in the broadcast schedule information is referenced is received by the receiving means The event included in the event message If it has passed the expiration date of the message, and a discarding means for discarding the event message.

A receiving method according to one aspect of the present invention includes: a receiving step for receiving content data of a broadcast program repeatedly transmitted in a data carousel method; and an event message for receiving the content data; a storage step of storing the content data, said included in the event message received in the receiving step, a detection step of detecting the broadcast schedule information for receiving the content data, the reception start time of the content data A determination step for determining with reference to the broadcast time included in the broadcast schedule information detected in the detection step, and a time at which the broadcast time included in the broadcast schedule information is referred to is received in the reception step The event menu Included in the message if, has passed the expiration date of the event message, and a waste step of discarding the event message.

In one aspect of the present invention, content data of a broadcast program repeatedly transmitted by a data carousel method and an event message for receiving the content data are received, the received content data is stored, and the received event contained in the message, the broadcast schedule information necessary for reception of the content data is detected, the reception start time of the content data, the broadcast time included in the detected broadcast schedule information is determined referenced, included in the broadcast schedule information time at which the broadcasting time has been references are included in the received event message, if you have passed the expiration date of the event message, event messages Ru is discarded.

According to the receiving apparatus and receiving method of the present invention, it is possible to update the content, easily and efficiently.

  FIG. 1 shows a data distribution system to which the present invention is applied (in this specification, a system means a logical collection of a plurality of devices, and whether or not the devices of each configuration are in the same casing. The example of a structure of one Embodiment is shown.

  The information providers A to C have databases 1a to 1c in which various data are stored. The databases 1a to 1c include, for example, traffic information, weather information, stock price information, and other data that changes in real time, data that does not change in real time, text data, image data, audio data, computers, etc. Everything such as a program (including data in a format provided by a point cast and data constituting a home page provided by the WWW (World Wide Web)) can be stored. Here, for example, a piece of information (for example, one file) such as traffic information and weather information is hereinafter referred to as contents or an object as appropriate.

  When an object (content) stored in the databases 1a to 1c is updated, that is, an object stored in the databases 1a to 1c is changed, an object is newly registered there, or there When the stored object is deleted, update object information for updating the object is transmitted to the server 2 constituting the broadcasting station, and the server 3 updates the database 3 based on the update object information. The

  Here, as updated object information, when an object is changed, for example, when the object after the change is registered, or when a new object is registered, for example, when the new object is deleted For example, a deletion command for the object is transmitted from the databases 1a to 1c to the server 2, respectively. In this case, the updated object information is equal to the changed object when the object is changed, and is equal to the new object when a new object is registered.

  When the server 2 updates the registered contents of the database 3 based on the updated object information, the updated object information is transmitted to at least two-way communication such as an analog public network, ISDN (Integrated Services Digital Network), the Internet, or the like. The data is transmitted to the mirror server 7 via a communication network 6 or a dedicated line which is a possible network. The mirror server 7 receives the update object information from the server 2 and updates the database 8 based on the update object information. Accordingly, the registration contents of the databases 3 and 8 are always the same.

  Furthermore, when the registered contents of the database 3 are updated, the server 2 adds data for adding an identifier for identifying an object to be updated by the updated object information to the updated object information (hereinafter referred to as a subject as appropriate). (Update data) is generated. That is, an identifier for identifying each object is associated with the object stored in the database 3, and the identifier of the object updated by the updated object information is added to the updated object information, so that the subject Is generated.

  The server 2 also generates data for acquiring the subject. That is, as will be described later, the subject may be transmitted from the server 2 via the broadcast network 4, and in this case, in order to acquire the subject, the time and channel at which the subject is broadcast are required. In addition, as will be described later, the subject is associated with a URL (Uniform Resorce Locator) or the like and may be managed by the server 2 or the mirror server 7. In this case, the URL is necessary to obtain the subject. It becomes. Therefore, in the server 2, such information is generated as data for acquiring the subject.

  Furthermore, the server 2 adds data (hereinafter referred to as “event” as appropriate) (notification data) to which the identifier of the object updated by the subject acquired based on the data is added to the data for acquiring the subject (notification data) Is generated. Here, since the generation of the subject is performed when the update of the object occurs, the event for acquiring the subject is the data for acquiring the subject and the data for notifying the update of the object at the same time. It can be said that.

  When a subject and an event for acquiring the subject are generated in the server 2, these are in accordance with a predetermined transmission schedule, for example, a satellite line, a CATV network, a terrestrial wave, and the like. Via a broadcast network 4, which is a one-way (or two-way) network capable of simultaneous broadcasting to users, for example, to a receiving terminal 5 made up of, for example, an IRD (Integrated Receiver and Decoder) or STB (Set Top Box). Sent to.

  That is, when a subject is generated and an event for acquisition (an event to which the same identifier as the subject is added) is generated, basically, the event is first transmitted via the broadcast network 4. Sent. Further, in the event transmitted in this way, when there is a description of the broadcast time or channel of the subject, the subject is transmitted via the broadcast network 4 at that broadcast time. Sent.

  Here, in the server 2, for example, a subject transmission schedule is established (broadcast time, broadcast channel, etc. are determined), and the broadcast time, broadcast channel, etc. of the subject are described in the event according to the transmission schedule. Is done. Then, a transmission schedule for the event is established.

  When a subject is associated with, for example, a URL and is managed by the server 2 or the mirror server 7, an event including the URL is generated and transmitted via the broadcast network 4. That is, when the subject is managed by the server 2 or the mirror server 7, an event including a URL having the IP address of the server 2 or the mirror server 7 as a domain name is generated and transmitted.

  The event transmitted (distributed) via the broadcast network 4 as described above is received by the user receiving terminal 5. In the receiving terminal 5, the received event is selected for an object desired by the user, and a subject is acquired based on the selected event.

  That is, for example, when an event includes a subject broadcast time and channel, the server 2 transmits the subject via the broadcast network 4 at the broadcast time at the broadcast time as described above. Therefore, the receiving terminal 5 receives the subject transmitted in this way.

  For example, when the URL associated with the subject is included in the event, the receiving terminal 5 accesses the server corresponding to the domain name of the URL via the communication network 6, Request and receive a subject.

  Specifically, if the server corresponding to the domain name of the URL included in the event is, for example, the server 2, the subject is under the management of the server 2. The server 2 is accessed via and the subject is acquired.

  In addition, if the server corresponding to the domain name of the URL included in the event is, for example, the mirror server 7, the subject is under the control of the mirror server 7. To access the mirror server 7 and obtain a subject.

  After receiving the subject as described above, the receiving terminal 5 updates the object stored in the receiving terminal 5 based on the subject.

  The subject is transmitted from the server 2 via the broadcast network 4 and may be placed under the management of the server 2 or the mirror server 7. Furthermore, in the embodiment of FIG. 1, only one mirror server 7 is shown, but a plurality of mirror servers that perform the same processing as the mirror server 7 can be provided on the communication network 6, and in this case The subject can be under the management of the plurality of mirror servers. Further, the subject may be transmitted from the server 2 via the broadcast network 4 not only at a certain time of a certain channel but also at a plurality of channels or at a plurality of times.

  As described above, when there are a plurality of methods for acquiring a subject, information about each of the plurality of methods (broadcast time, broadcast channel, URL, etc.) is included in the event. Whether the subject is acquired by the method is determined by the receiving terminal 5. That is, for example, when an event includes a plurality of times for transmitting a subject via the broadcast network 4, the receiving terminal 5 receives, for example, a subject broadcast at a time closest to the current time. Thus, the subject is acquired. Further, for example, when an event includes a plurality of URLs, the server closest to the receiving terminal 5 is selected, and the subject is selected from the server via the communication network 6. A subject is acquired by making a request. Furthermore, for example, when the event includes a time for transmitting a subject via the broadcast network 4 and a URL, for example, when the line state of the broadcast network 4 is poor (S / N (Signal / Noise)) When the password is low, the subject is acquired based on the URL as described above. In addition, which method the subject is acquired by may be determined based on the operation of the user of the receiving terminal 5 or the like.

  According to the data distribution system as described above, an event in which a subject acquisition method is described is distributed via the broadcast network 4, and the subject is acquired based on the event at the receiving terminal 5, and the object is updated. Thus, efficient data distribution can be performed while suppressing an increase in the load on the receiving terminal 5.

  That is, generally, a subject has a large amount of data including updated object information for object update (especially object change and new registration), and the subject is generated corresponding to the object update. I don't know if it happens. Therefore, if only such a subject that occurs irregularly and has a large amount of data is transmitted as early as possible through the broadcast network 4, the server 2 uses the currently available channel, A subject needs to be sent. However, in this case, the receiving terminal 5 needs to wait for a subject that does not know when and in which channel the data is transmitted, which increases the burden.

  In contrast, since an event includes a description of how to obtain a subject, the amount of data is generally much less than that of a subject that includes updated object information, and thus, for example, for a narrowband channel. Furthermore, it is possible to transmit at a fixed time. Therefore, in this case, the receiving terminal 5 has only to receive an event in the channel (further, it is transmitted at a fixed time), and the load is much higher than when waiting for transmission of a subject. Get smaller.

  Furthermore, in the present embodiment, since the event is transmitted via the broadcast network 4 that can broadcast simultaneously over a wide area, the increase in the number of receiving terminals 5 causes the load on the server 2 and the broadcast network 4 to increase. It will not affect

  In the present embodiment, the subject is provided not only via the communication network 6 but also via the broadcast network 4, so that the server 2 and the mirror server 7 can obtain the subject. Access is rarely concentrated, thus enabling efficient distribution of subjects.

  The broadcast network 4 and the communication network 6 do not have to be physically separate networks. That is, when the broadcast network 4 is configured by, for example, a CATV network, the CATV network can also be used as the communication network 6. Further, in the case where data distribution by the broadcast network 4 is performed by, for example, IP (Internet Protocol) multicast using the Internet or the like, the communication network 6 can also be configured by the Internet.

  Furthermore, the transmission of data (events and subjects) from the server 2 to the receiving terminal 5 is performed, for example, by scrambled, so that only specific users (users with a receiving contract) can receive the data. It is also possible to do so.

  Next, FIG. 2 shows a configuration example of the server 2 of FIG.

  The communication control unit 11 includes, for example, a modem, a TA (Terminal Adapter), and the like, and controls communication via the communication network 6. The resource allocation unit 12 performs resource allocation for data transmission via the broadcast network 4. That is, the resource allocation unit 12 receives notification of the update of the object from the registration unit 15, and in response to the update, allocates resources for transmitting the event and subject via the broadcast network 4 (for example, event and object). Transmission channel, transmission time (time), data rate, number of transmissions (transmission frequency), etc.). Resource allocation results for event and subject transmission by the resource allocation unit 12 are supplied to the data configuration unit 17 and the transmission unit 18.

  The data search unit 13 receives a request for a subject transmitted from the receiving terminal 5 via the communication network 6 from the communication control unit 11, and searches the database 3 for updated object information constituting the subject. The data search unit 13 configures a subject in the same manner as the data configuration unit 17 described later, and supplies the subject to the communication control unit 11. The replication management unit 14 manages information for specifying the mirror server 7 (further, a mirror server (not shown) on the communication network 6). That is, for example, when the communication network 6 is the Internet, the replication management unit 14 stores the IP address of the mirror server 7. Upon receiving notification of the update of the object from the registration unit 15, the replication management unit 14 reads the update object information for the update from the database 3 and controls the communication control unit 11 to update the update object information. For example, the information is transmitted to a server on the communication network 6 having an IP address managed by the mirror server 7 or the like. The replication management unit 14 supplies information managed by itself to the data configuration unit 17 as necessary.

  The registration unit 15 receives the update object information supplied from the databases 1a to 1c of the information providers A to C, and updates the object (database 3) based on the update object information. That is, the identifiers of the objects updated by the updated object information are supplied from the databases 1a to 1c of the information providers A to C together with the updated object information. The registration unit 15 receives the updated object information and the identifier, and searches the database 3 for an object corresponding to the identifier. Further, the registration unit 15 updates the object thus searched based on the updated object information, and then notifies the resource allocation unit 12, the replication management unit 14, and the data configuration unit 17 that the object has been updated. Output. Note that the registration unit 15 also registers the updated object information and identifiers from the databases 1 a to 1 c in the database 3.

  When receiving the fact that the object has been updated from the registration unit 15, the data configuration unit 17 reads the updated object information about the updated object from the database 3, and generates a subject in which the updated object information is arranged. And output to the transmission unit 18. Further, the data configuration unit 17 generates an event for acquiring the subject and outputs the event to the transmission unit 18. In the data configuration unit 17, an event is generated using the resource allocation result by the resource allocation unit 12 and information supplied from the replication management unit 14. That is, the data configuration unit 17 transmits the subject transmission channel, time, data rate, information on the server that manages the subject, and the like from the resource allocation result by the resource allocation unit 12 and the copy management unit 14. Recognized from information and included in events.

  The transmission unit 18 broadcasts the event or subject from the data configuration unit 17 according to the resource allocation result of the resource allocation unit 12, that is, for example, at a predetermined channel and a predetermined data rate at a predetermined data rate. Transmission is performed via the network 4.

  Next, FIG. 3 shows a configuration example of the mirror server 7 of FIG. In the figure, portions corresponding to those in the server 2 of FIG. That is, the mirror server 7 is basically configured in the same manner as the server 2 except that the resource allocation unit 12, the replication management unit 14, the data configuration unit 17, and the transmission unit 18 are not provided. In the registration unit 15 constituting the mirror server 7, the update object information transmitted via the communication network 6 or the like is transmitted by the replication management unit 14 constituting the server 2 by controlling the communication control unit 11. It is made to be supplied.

  In the server 2 configured as described above, a registration process for registering data in the database 3 (updating the registration contents of the database), a data transmission process for generating a subject and an event, and transmitting them through the broadcast network 4 and reception When a request for a subject is received from the terminal 5 via the communication network 6, a request data transmission process for transmitting the subject via the communication network 6 is performed. In the mirror server 7, registration processing and request data are performed. Transmission processing and the like are performed.

  First, registration processing performed by the server 2 will be described with reference to the flowchart of FIG.

  In the registration process, first, in step S1, the registration unit 15 determines whether or not the updated object information and the identifier are distributed from any of the databases 1a to 1c of the information providers A to C. If it is determined that it has not been distributed, the process returns to step S1. If it is determined in step S1 that the update object information and the identifier have been distributed, the process proceeds to step S2, and the registration unit 15 adds the identifier to the update object information and registers it in the database 3, for example. .

  Here, from the databases 1a to 1c, update object information and identifiers are supplied in a format as shown in FIG. 5, for example.

  Here, the identifier is, for example, traffic information, weather information, stock price information, and a unique ID (Identifier) assigned in advance for each object type such as a component constituting the information, and an object. Version information indicating the newness of As the version information, for example, an integer value that is incremented by 1 every time the object is updated is used. Therefore, the version information is compared with respect to the object to which the same ID is added. Thus, the latest object can be recognized.

  The ID and version information are both fixed length here, for example.

  When the registration unit 15 adds (associates) the identifiers distributed from the databases 1a to 1c to the updated object information distributed from the databases 1a to 1c, in step S2, the IDs constituting the identifiers are added. The object to which the identifier having the same ID is added is searched from the database 3 and updated based on the updated object information. Then, the registration unit 15 increments the version information of the identifier added to the updated object by, for example, 1.

  Thereafter, in step S3, the registration unit 15 outputs information indicating that the object has been updated to the resource allocation unit 12, the replication management unit 14, and the data configuration unit 17, and returns to step S1.

  In the copy management unit 14 that has received the fact that the object supplied as described above has been updated, the updated object information registered in the database 3 and the identifier added thereto are read out in step S2 and managed by itself. In this case, the data is transmitted to the mirror server 7 via the communication network 6. In addition, the replication management unit 14 outputs the specific information for specifying the server that has transmitted the update object information and the identifier, that is, here, for example, the IP address of the mirror server 7 to the data configuration unit 17.

  In the mirror server 7, the process excluding step S3 of steps S1 to S3 in FIG. 3 is performed as a registration process. That is, in the mirror server 7, in step S1, it is determined by the registration unit 15 whether or not the updated object information and the identifier have been distributed from the server 2, and when it is determined that the updated object information and the identifier have not been distributed, the process returns to step S1. . If it is determined in step S1 that the update object information and the identifier have been distributed, the process proceeds to step S2, and the registration unit 15 of the mirror server 7 adds the identifier to the update object information and registers it in the database 8. . Further, the registration unit 15 of the mirror server 7 searches the database 8 for an object to which an identifier having the same ID as that constituting the identifier received from the server 2 is added in step S2, and the object is Update based on the update object information received from the server 2. Then, the registration unit 15 of the mirror server 7 increments the version information of the identifier added to the updated object by 1, skips step S3, and returns to step S1.

  In the server 2, the fact that the object output from the registration unit 15 is updated in step S3 by performing the registration process as described above is supplied to the duplication management unit 14, as well as the resource allocation unit 12 and the data The component 17 is also supplied.

  When the resource allocating unit 12 receives information that the object has been updated, the resource allocating unit 12 allocates resources for transmitting the event and subject relating to the update via the broadcast network 4, and the allocation result is assigned to the data configuration unit 17 and The data is output to the transmission unit 18. When receiving the fact that the object has been updated, the data configuration unit 17 reads updated object information about the updated object from the database 3, generates a subject, and outputs the subject to the transmission unit 18. Furthermore, the data configuration unit 17 sets the event for acquiring the subject, the resource allocation result of the resource allocation unit 12 and the information from the replication management unit 14 (for example, the IP address of the mirror server 7 as described above). And output to the transmission unit 18. In the transmission unit 18, the event or subject from the data configuration unit 17 is transmitted via the broadcast network 4 according to the resource allocation result of the resource allocation unit 12. That is, the resource allocation unit 12, the data configuration unit 17, and the transmission unit 18 perform data transmission processing as shown in FIG.

  That is, in the data transmission process, first, a resource allocation process is performed in step S11. Specifically, in step S11, when the resource allocating unit 12 receives information that the object has been updated, the broadcast channel for transmitting the event and object relating to the update via the broadcast network 4, the broadcast time, Determine the data rate, number of transmissions, etc. These resource allocation results are supplied to the data configuration unit 17 and the transmission unit 18.

  In step S12, the data structure unit 17 generates an event and a subject. That is, the data configuration unit 17 reads the updated object information used for updating the object and the identifier added thereto from the database 3, and configures a subject as shown in FIG. 7A, for example. In FIG. 7A (also in FIG. 7B), a discrimination flag is arranged immediately after the version information. This discrimination flag indicates whether the data is a subject or an event. Represents.

  Further, the data configuration unit 17 configures an event such as that shown in FIG. 7B, for example, in which the same identifier as the identifier added to the subject is added to the subject. That is, the event is configured by sequentially arranging a determination flag, broadcast schedule information, and server access information on the same identifier as the identifier added to the subject.

  The broadcast schedule information is information necessary to receive a subject when the subject is broadcast via the broadcast network 4, and includes a broadcast channel of the subject which is a resource allocation result from the resource allocation unit 12. Broadcast time (time), data rate, number of transmissions, and the like. Therefore, by referring to the broadcast schedule information constituting the event, it is possible to recognize the broadcast channel, broadcast time, etc. of the subject for updating the object of the identifier constituting the event, thereby receiving the subject. It becomes possible to do.

  The server access information is information necessary for requesting a subject via the communication network 6 when the subject is transmitted from the server 2 or the mirror server 7 via the communication network 6. For example, the IP addresses of the server 2 and the mirror server 7 are included. The IP address and the like are supplied from the replication management unit 14 to the data configuration unit 17 as identification information for identifying the server 2 and the mirror server 7.

  That is, the server 2 and the mirror server 7 compose the subject shown in FIG. 7A from the update object information stored in the databases 3 and 8 and the identifier added thereto, and the request from the receiving terminal 5 The subject is transmitted via the communication network 6, and the server access information is referred to when the subject is acquired in this way.

  Here, in the server 2 and the mirror server 7, for example, a subject composed of update object information and an identifier added thereto is associated with a URL configured by adding the identifier to an IP address, Management is made to be performed. In this case, the receiving terminal 5 that has received the event can recognize the URL of the subject to which the same identifier as the event is added, from the server access information and the identifier constituting the event.

  The subject can be provided only via the broadcast network 4, but in this case, the server access information is not arranged in the event for the subject. Conversely, the subject can be provided only via the communication network 6, but in this case, broadcast schedule information is not arranged in the event for the subject.

  When a subject is transmitted via a broadcast network 4 at a plurality of channels or at a plurality of times, an event about the subject includes a broadcast schedule corresponding to each of the plurality of channels or a plurality of times. Information is arranged. Similarly, when a subject can be provided from a plurality of servers via the communication network 6, server access information corresponding to each of the plurality of servers is arranged in the event for the subject.

  When both broadcast schedule information and server access information exist, or when there are a plurality of broadcast schedule information or server access information, not all of them are included in one event, but one of them. An event may be generated every time.

  Returning to FIG. 6, when the event and subject as described above are generated in step S <b> 12, the event and subject are supplied from the data configuration unit 17 to the transmission unit 18. In the transmission unit 18, in step S <b> 13, the event or subject from the data configuration unit 17 is transmitted via the broadcast network 4 according to the resource allocation result from the resource allocation unit 12. That is, the event or subject is transmitted via the broadcast network 4 at a predetermined data rate at a predetermined transmission time on a predetermined transmission channel, for example, and the process proceeds to step S14.

  In step S14, the transmission unit 18 determines whether or not the transmission of the event or subject from the data configuration unit 17 has been repeated for the number of transmissions included in the resource allocation result from the resource allocation unit 12, and determines that it has not been performed. If so, the process returns to step S13, and event and subject transmission is repeated. That is, data transmission by the broadcast network 4 is performed only in one direction from the server 2 to the receiving terminal 5, and thus it is not possible to confirm whether or not data transmission / reception has been performed correctly between them. Therefore, the server 2 is configured such that data transmission is repeated as many times as the number of transmissions, which is a resource allocation result by the resource allocation unit 12, and thereby the probability that the receiving terminal 5 will receive accurate data. Has been made to improve.

  On the other hand, if it is determined in step S14 that the transmission of the event or subject from the data configuration unit 17 has been repeated for the number of transmissions included in the resource allocation result from the resource allocation unit 12, the data transmission process is terminated.

  As described above, since an event generally has a small amount of data and a subject has a large amount of data, the resource allocation unit 12 basically increases the number of transmissions for an event and decreases for a subject. In addition, resource allocation is performed. Therefore, in the receiving terminal 5, the probability that the event transmitted via the broadcast network 4 is missed (the probability that it cannot be received) is reduced, and if the event can be normally received, for example, the broadcast schedule information included therein By referring to, the subject can recognize the channel and time transmitted via the broadcast network 4, and as a result, the probability of missing an event with a small number of transmissions can be reduced. In addition, even if the subject has failed to receive the broadcast channel or broadcast time based on the event, or if the subject is required prior to the broadcast time, If the server access information is included in the event, the subject can be acquired early and reliably by accessing the server 2 or the mirror server 7 via the communication network 6 based on the server access information. Can do.

  Next, a request data transmission process performed by the server 2 and the mirror server 7 will be described with reference to the flowchart of FIG.

  In this case, in step S21, the communication control unit 11 determines whether, for example, a URL has been transmitted as a subject request from the receiving terminal 5 via the communication network 6, and it is determined that it has not been transmitted. If so, the process returns to step S21. If it is determined in step S <b> 21 that the URL has been transmitted, the communication control unit 11 transfers the URL to the data search unit 13. When receiving the URL, in step S22, the data search unit 13 searches for updated object information to which the same identifier as the data identifier constituting the URL is added (the server 2 searches the database 3 for the mirror object, 7 is searched from the database 8).

  That is, in the present embodiment, as described above, in the receiving terminal 5 that has received the event, the same identifier as that event is added from the IP address as the server access information constituting the event and the identifier. The subject URL is recognized. When the receiving terminal 5 requests a subject via the communication network 6, the receiving terminal 5 transmits the URL. Therefore, the URL from the receiving terminal 5 includes an identifier, and the server 2 and the mirror server 7 search for the identifier as a file name of the update object information.

  In step S22, when the update object information is searched, the data search unit 13 configures a subject by adding the identifier stored together with the update object, and supplies the subject to the communication control unit 11. The communication control unit 11 receives the subject from the data search unit 13, and transmits it to the receiving terminal (here, the receiving terminal 5) that has transmitted the URL via the communication network 6 in step S23. Return to step S21.

  Next, FIG. 9 shows a configuration example of the receiving terminal 5 of FIG.

  The receiving unit 21 receives data transmitted from the server 2 via the broadcast network 4, that is, here, an event and a subject, and outputs them to the selecting unit 22. The selection unit 22 selects an event or subject from the reception unit 21. Further, the selection unit 22 is configured to temporarily store the selected event in the database 23. Further, the selection unit 22 searches the database 23 for an object to which the same identifier as the identifier included in the selected subject is added, and updates the object based on the updated object information included in the subject. Yes.

  The database 23 is composed of, for example, a large-capacity hard disk, magneto-optical disk, or other recording medium, stores objects, and temporarily stores events from the selection unit 22.

  The communication control unit 24 performs communication control via the communication network 6, whereby a request for a subject from the request unit 25 is sent to the server 2, the mirror server 7, etc. via the communication network 6. A subject that is transmitted or transmitted from the server 2 or the mirror server 7 via the communication network 6 is received.

  The request unit 25 controls the reception unit 21 so as to receive a subject transmitted via the broadcast network 4 in accordance with broadcast schedule information included in an event stored in the database 23. . Further, the request unit 25 requests a subject from the server 2 or the mirror server 7 via the communication network 6 according to the server access information included in the event stored in the database 23, and responds to the request. The communication control unit 24 is also controlled so as to receive a subject transmitted from the server 2 or the mirror server 7 via the communication network 6. Further, the request unit 25 searches the database 23 for an object corresponding to the identifier included in the subject received by the communication control unit 24, and updates it based on the updated object information included in the subject. Yes. The request unit 25 performs the above-described processing, for example, periodically, and also when an object update request is received from the reading unit 26.

  The reading unit 26 reads an object stored in the database 23 in response to an operation of the operation unit 28 and supplies the object to the output unit 27. The output unit 27 includes, for example, a display, a speaker, and the like, and displays an object from the reading unit 26 or the like or outputs it as sound. The operation unit 28 is operated when a predetermined input is given to the reading unit 26.

  In the reception terminal 5 configured as described above, a reception process for receiving data transmitted from the server 2 via the broadcast network 4 and a data request process for requesting a subject based on an event stored in the database 23. , And an output process for outputting data registered in the database 23.

  First, the reception process will be described with reference to the flowchart of FIG.

  When data is transmitted from the server 2 via the broadcast network 4, the reception unit 21 receives the data, that is, an event or a subject, and supplies the data to the selection unit 22 in step S 31. In step S32, the selection unit 22 determines whether an event or subject from the reception unit 21 is to be selected.

  That is, when all events and subjects transmitted from the server 2 via the broadcast network 4 are received, the database 23 requires a huge storage capacity. In addition, the user has a preference and each user rarely needs all the objects stored in the database 3 of the server 2. Nevertheless, it is not preferable to reflect all the registered contents of the database 3 of the server 2 in the database 23.

  Therefore, if, for example, an ID of an object desired by the user (ID constituting the above-described identifier) is registered in the selection unit 22, the selection unit 22 can only select events and objects having the same ID as the ID. Has been made to choose. Therefore, the determination in step S <b> 32 is performed by comparing the ID registered by the user with the IDs constituting the event and subject identifiers supplied from the receiving unit 21.

  If it is determined in step S32 that the event or subject from the receiving unit 21 is not to be selected, for example, the ID registered by the user and the ID described in the event or subject supplied from the receiving unit 21 If does not match, the process waits for the next event or subject to be transmitted via the broadcast network 4 and returns to step S31. Therefore, in this case, the event is not stored in the database 23, and the database 23 is not updated based on the subject.

  On the other hand, when it is determined in step S32 that the event or subject from the receiving unit 21 is to be selected, for example, the ID registered by the user and the event or subject supplied from the receiving unit 21 are described. If the ID matches, the process proceeds to step S33, and the selection unit 22 determines whether the event or subject is related to a new object.

  If it is determined in step S33 that the event or subject selected in step S32 relates to a new object, that is, an object having the same ID as the ID included in the event or subject is stored in the database 23. If not registered, the process skips step S34 and proceeds to step S35.

  If it is determined in step S33 that the event or subject selected in step S32 is not related to a new object, that is, an object having the same ID as that included in the event or subject is stored in the database. If it is registered in 23, the process proceeds to step S34, and the version information described in the identifier of the object already registered in the database 23 (hereinafter referred to as “registered object” as appropriate) is selected in step S34. It is determined whether the version information described in the identifier of the event or subject selected in S32 is equal.

  In step S34, when the version information described in the registered object is equal to the version information described in the event or subject selected in step S32, that is, here, the data transmission process of FIG. As described above, in order to improve the reliability, the same subject is repeatedly transmitted from the server 2 via the broadcast network 4. Of the repeated transmissions as described above, the subject by the transmission performed in the past. Thus, if the registered object has already been updated, steps S35 to S37 are skipped, and after waiting for an event or subject to be transmitted, the process returns to step S31. Therefore, in this case, the event is not stored in the database 23, and the database 23 is not updated based on the subject.

  On the other hand, if it is determined in step S34 that the version information described in the registered object is not equal to the version information described in the event or subject selected in step S32, that is, the event or subject is If it is related to a new version of the object, the process proceeds to step S35, and the selection unit 22 determines whether the data selected in step S32 is an event or a subject by referring to the determination flag. Is done.

  If it is determined in step S35 that the data selected in step S32 is a subject, the process proceeds to step S36, and the selection unit 22 updates the database 23 based on the subject.

  That is, when a new object is arranged as updated object information in a subject, the new object is associated with an identifier included in the subject and newly registered in the database 23.

  In addition, when an updated object is arranged as updated object information in a subject, an object associated with an identifier having the same ID as the ID included in the subject is searched from the database 23, The searched object is changed to the updated object. Further, the version information associated with the object is incremented by 1, for example.

  Furthermore, in the subject, when an object deletion instruction is arranged as update object information, an object associated with an identifier having the same ID as the ID included in the subject is searched from the database 23, It is deleted with the identifier associated with the object.

  Note that the update of the object based on the updated object information performed in step S2 of the registration process described with reference to FIG. 4 is performed in the same manner.

  In step S36, after the database 23 has been updated as described above, next, it waits for an event or subject to be transmitted, and then returns to step S31.

  On the other hand, if it is determined in step S35 that the data selected in step S32 is an event, the process proceeds to step S37, and the selection unit 22 supplies the event to the database 23 and temporarily stores the event. Then, after waiting for an event or subject to be transmitted, the process returns to step S31.

  In step S37, the event stored in the database 23 is deleted after being read from the database 23 by the request unit 25 in the data request process (FIG. 11) and the data output process (FIG. 12) described later. It is made so that.

  Next, the data request process will be described with reference to FIG. This data request process is periodically performed at the receiving terminal 5. However, the data request process can be performed irregularly.

  In the data request process, first, in step S41, the registration content of the database 23 is retrieved by the request unit 25, and the process proceeds to step S42 to determine whether or not an event is stored in the database 23. If it is determined in step S42 that no event is stored, the data request process is terminated.

  If it is determined in step S42 that an event is stored in the database 23, the event is read (if a plurality of events are stored, one of them is read). The request unit 25 determines whether it is advantageous to receive the subject based on the event via the broadcast network 4 capable of broadcasting or the communication network 6 capable of bidirectional communication. The

  Here, the determination in step S43 is performed as follows, for example.

  That is, the request unit 25 refers to the broadcast schedule information included in the event, so that the number of transmissions (transmission frequency) in which the subject with the same identifier as the identifier added to the event is transmitted and the transmission time are determined. Be recognized. For example, when the number of transmissions is large or when the transmission time is close to the current time, the reception time of the subject is received via the broadcast network 4 where the reception time of the subject and other costs for reception are expected to be low. Is determined to be advantageous.

  For example, when the number of transmissions is small or the transmission time is far from the current time, it is determined that it is advantageous to receive the subject via the communication network 6.

  In addition, for example, when the data amount of the subject is described in the broadcast schedule information included in the event (even if the data amount itself is not described, the data rate and the time required for transmission are described. If this is the case, the amount of data can be recognized), and based on the amount of data, it is determined whether it is advantageous to receive the subject via the broadcast network 4 or the communication network 6 It is also possible.

  Further, whether the subject is advantageous to be received through the broadcast network 4 or the communication network 6 is determined by the user operating the operation unit 28 and determined in accordance with the operation. Is also possible.

  Further, when receiving a subject via the communication network 6, the communication network 6 supports a plurality of transmission rates, and the receiving terminal 5 performs communication via a line having such a plurality of transmission rates. When possible, it is possible to change the line to be used according to the data amount of the subject.

  Here, as described above, an event may include only one of broadcast schedule information and server access information. If the event includes only broadcast schedule information, it is determined in step S43 that it is advantageous to receive the subject via the broadcast network 4. Conversely, if the event includes only server access information, it is determined in step S43 that it is advantageous to receive the subject via the communication network 6.

  If it is determined in step S43 that it is advantageous to receive the subject via the broadcast network 4, the process proceeds to step S44, and the request unit 25 determines whether or not the reception unit 21 is operable ( For example, it is determined whether or not power is supplied (whether it is not in a sleep state). In step S44, when it is determined that the receiving unit 21 is not in an operable state, the process proceeds to step S45, and the request unit 25 waits until, for example, immediately before the transmission time of the subject arranged in the broadcast schedule information of the event. Thus, when the receiving unit 21 is in an operable state, that is, when the receiving unit 21 is in the sleep state, the power supply is started, and the process proceeds to step S46.

  If it is determined in step S44 that the receiving unit 21 is in an operable state, step S45 is skipped and the process proceeds to step S46. The request unit 21 controls the receiving unit 21 to control the database 23. In the transmission channel arranged in the broadcast schedule information of the event read out from the subject, it is added to the subject, that is, the event transmitted through the broadcast network 4 at the transmission time arranged in the broadcast schedule information. The subject having the same identifier as the existing identifier is received and supplied to the selection unit 22. In step S47, the selection unit 22 updates the database 23 based on the subject from the reception unit 21 in the same manner as in step S36 in FIG.

  Here, in the receiving terminal 5, data loss often occurs due to the power supply of the receiving unit 21 being turned off. Therefore, as described above, it is determined whether or not the receiving unit 21 is in an operable state. If the receiving unit 21 is not in an operable state, the receiving unit 21 is set in an operable state, whereby the power source of the receiving unit 21 is It is possible to prevent the subject from being missed due to being in the off state.

  On the other hand, if it is determined in step S43 that it is advantageous to receive the subject via the communication network 6, the process proceeds to step S48, and the request unit 25 controls the communication control unit 24 to control the database 23. The server 2 and the mirror server 7 are requested via the communication network 6 for a subject to which the same identifier as the identifier included in the event read from is added.

  That is, the request unit 25 adds the same identifier as the identifier included in the event read from the database 23 and the server access information (here, the IP address as described above). The URL associated with the subject is configured, and the communication control unit 24 is controlled to transmit the URL to the server 2 or the mirror server 7 via the communication network 6.

  In the server 2 and the mirror server 7 to which the URL is transmitted, the request data transmission process described with reference to FIG. 8 is performed, whereby the subject associated with the URL is transmitted via the communication network 6. . This subject is received by the communication control unit 24 and supplied to the request unit 25 in step S49. Upon receiving the subject from the communication control unit 24, the request unit 25 proceeds to step S47, updates the database 23 based on the subject as described above, and ends the data request process.

  As described above, it is determined whether it is advantageous to receive the subject via the broadcast network 4 or the communication network 6, and the subject transmitted via the advantageous one is received. The receiving terminal 5 can efficiently receive the subject and update the object.

  In the case where the subject is received via the broadcast network 4, when a plurality of transmission times are arranged in the broadcast schedule information of the event, for example, the transmission time closest to the current time (however, the current time) A subject that is transmitted before (excluding the time in the past) is received. However, it is also possible to have the user operate the operation unit 28 to select a transmission time.

  Further, when requesting and receiving a subject via the communication network 6, when the IP addresses of a plurality of servers are arranged in the server access information of the event, for example, the position closest to the receiving terminal 5 among them The URL is constructed using the IP address of the server in However, it is also possible to have the user operate the operation unit 28 to select a server.

  Next, data output processing will be described with reference to the flowchart of FIG. The data output process is basically started periodically, for example, as in the data request process of FIG.

  In the data output process, first, in step S51, it is determined by the reading unit 26 whether or not the operation unit 28 has been operated so as to output data (an object in the present embodiment). If it is determined that is not operated, the data output process is terminated.

  If it is determined in step S51 that the operation unit 28 has been operated to output an object, the process proceeds to step S52, and an event for the object requested to be output, that is, the same identifier as the identifier of the object. The reading unit 26 determines whether or not the event to which “” is added is stored in the database 23. In step S52, when it is determined that the event for the object whose output is requested is not stored in the database 23, that is, the object whose output is requested is the latest stored in the database 23. In the case where it is determined that there is no event missing, the process proceeds to step S53, where the reading unit 26 reads the object requested to be output from the database 23 and supplies it to the output unit 27. In the output unit 27, the object from the reading unit 26 is displayed or output with sound, and the data output process is terminated.

  If it is determined in step S52 that the event for the object requested to be output is stored in the database 23, that is, the object requested to be output is updated in the server 2, but received. If the terminal 5 has not yet been updated, the process proceeds to step S54, and the reading unit 26 determines whether or not to update the object.

  That is, in step S54, the reading unit 26 displays a message for inquiring whether or not to update the object on the output unit 27, and prompts the user to operate the operation unit 28. In step S54, it is determined whether or not to update the object in response to the operation of the operation unit 28.

  Alternatively, in step S54, the broadcast schedule information of the event for the object requested to be output is referred, and the subject for updating the object is transmitted among the transmission times transmitted via the broadcast network 4. The one closest to the current time is recognized. In step S54, it is determined whether or not to update the object in correspondence with whether or not the transmission time closest to the current time is within a predetermined time set in advance in the receiving terminal 5 from the current time. (If the transmission time is within a predetermined time from the current time, it is determined to update the object).

  In step S54, when it is determined not to update the object requested to be output, the process proceeds to step S55, and the reading unit 26 reads the object requested to be output, that is, the object before update from the database 23. Thereafter, in the same manner as in step S53, the data is output to the output unit 27 and the data output process is terminated. In this case, the output unit 27 may output the object and display a message indicating that the object is not updated.

  On the other hand, if it is determined in step S54 that the object requested to be output is to be updated, the process proceeds to step S56, and a database update process for updating the object is performed. That is, in step S56, the same process as in the data request process in steps S43 to S49 in FIG. 11 is performed using the event for the object requested to be output. Updated. In step S53, the updated object is output from the output unit 27 as described above, and the data output process ends.

  By the way, in the case where the IP addresses of a plurality of servers are arranged in the server access information of the event, the server from which the subject is requested is determined, for example, as described above, If the determination is made in response to the operation of the operation unit 28 by the user, access to a certain server may be concentrated.

  Therefore, when there are a plurality of servers that transmit the subject to the receiving terminal 5 via the communication network 6 (for example, as shown in FIG. 1, in addition to the server 2, a mirror server 7 exists, In the case where there are further mirror servers other than the server 7), in order to distribute access to the server (in order not to concentrate access to one server), the receiving terminal 5 or its user has a unique ID ( Hereinafter, the server 2 is given a user ID as appropriate, and the server 2 is associated with each server's IP address and assigned to the event as server access information (hereinafter referred to as a load balancing process as appropriate). ) Can be made to send the event. On the other hand, the receiving terminal 5 performs processing for recognizing the server of the IP address associated with its own user ID (hereinafter referred to as access server determination processing as appropriate), and then requests that server to request a subject. Can be.

  FIG. 13 shows a flowchart of the load distribution process performed by the server 2. Note that this load distribution processing is performed when there are a plurality of servers that send a subject to the receiving terminal 5 via the communication network 6 (in addition to the server 2, the subject is sent via the communication network 6). For example, as part of the process of step S12 in the data transmission process of FIG.

  In the load distribution process, first, in step S61, the number of receiving terminals (hereinafter referred to as the number of assignments as appropriate) N assigned to one server that transmits a subject is calculated via the communication network 6. That is, in step S61, for example, the total number of receiving terminals is divided by the total number of servers that transmit the subject via the communication network 6, and the divided value (for example, rounded up after the decimal point) is assigned number N. The Note that the server 2 manages the total number of receiving terminals. In the server 2, the total number of servers that transmit the subject via the communication network 6 is recognized from information managed by the replication management unit 14.

  Thereafter, in step S62, one of a plurality of servers that transmit the subject is selected via the communication network 6 (this selected server is hereinafter referred to as a selected server as appropriate), and the process proceeds to step S63. The receiving terminal located near the selected server is detected by the assigned number N. It is assumed that the positions of the selected server and the receiving terminal 5 are managed in the server 2.

  In step S64, the user ID of each of the N receiving terminals detected in step S63 is associated with the IP address of the selected server, and the set of the IP address and the N user IDs is determined as server access. Information is placed in the event. Thereafter, the process proceeds to step S65, and it is determined whether or not the processes of steps S62 to S64 have been performed using all the plurality of servers transmitting the subject via the communication network 6 as selected servers. If it is determined in step S65 that all of the plurality of servers have not yet been processed as selected servers, the process returns to step S62, and a server not yet selected as a selected server is newly selected as a selected server. Similar processing is repeated. On the other hand, if it is determined in step 65 that the process has been performed with all of the plurality of servers as the selected server, the load distribution process is terminated.

  As described above, in load distribution processing, N (or N-1) receiving terminals are allocated to one server.

  In the case described above, the total number of receiving terminals is simply divided by the total number of servers that transmit the subject via the communication network 6 as the number of receiving terminals assigned to one server. The number of receiving terminals allocated to each of the plurality of servers may be determined in consideration of, for example, the processing capability of each server.

  Next, the access server determination process performed by the receiving terminal 5 will be described with reference to the flowchart of FIG. This access server determination process is performed at the receiving terminal 5 before, for example, constructing the URL to be transmitted in step S48 of the data request process of FIG.

  In the access server determination process, in step S71, the receiving terminal 5 searches for the user ID assigned to itself from the server access information of the event, and proceeds to step S72. In step S72, the IP address associated with the user ID, that is, the server that should request the subject is recognized, and the access server determination process is terminated.

  In the receiving terminal 5, as described with reference to FIG. 11, in step S48, a URL is constructed and transmitted using the IP address recognized in step S72.

  As described above, by performing load distribution processing or access server determination processing in the server 2 or the receiving terminal 5 respectively, the request for the subject from the receiving terminal can be distributed to a plurality of servers, and an efficient subject is obtained. Can be delivered.

  In the above case, the user ID of the receiving terminal is associated with the IP address and the server that the receiving terminal should access is limited. For example, the user ID of the receiving terminal and the server The access to the server can also be distributed by associating the time zone (request timing information) accessible via the communication network 6 and limiting the time zone in which the receiving terminal accesses the server. Is possible.

  The data distribution system to which the present invention is applied has been described above. Such a data distribution system is, for example, a case where data is distributed to a large number of databases in a distributed database, or a case where data is distributed by IP multicast. It is particularly useful when distributing data to an unspecified number of others.

  In the present embodiment, the event is transmitted via the broadcast network 4. However, for example, the event may be transmitted via the communication network 6 in response to a request from the receiving terminal 5. good. Furthermore, in the present invention, it is not essential to have both the broadcast network 4 and the communication network 6. That is, the present invention can be applied to a system including only one of the broadcast network 4 and the communication network 6.

  In this embodiment, the IP addresses of the server 2 and the mirror server 7 are arranged in the server access information. However, for example, the server access information is managed by the server 2 or the mirror server 7. It is also possible to arrange a URL of a subject, a telephone number for accessing the server 2 or the mirror server 7, and the like.

  Further, it is possible to cause the mirror server 7 to update the database 8 by receiving events and subjects in the same manner as the receiving terminal 5.

  Furthermore, in the present embodiment, the updated object itself is arranged as the updated object information to be included in the subject. However, as the updated object information, for example, the updated object is added to the updated object. Data that reflects the changes made to the data (for example, an executable computer program that changes the object before the update to the object after the update, the difference between the object after the update and the object before the update, etc.) It is also possible to do.

  Next, in FIG. 7, the outline of the data structure of the event generated by the data configuration unit 17 has been described. However, the event configured by the data configuration unit 17 is realized on, for example, an arbitrary transport protocol. The format for this will be described in detail.

  Here, the event format is ANS. It is expressed by an abstract syntax expression using 1 (Abstract Syntax Notation One).

  Here, ANS. The format represented by 1 is ASN. Based on 1 encoding rule BER (Basic Encoding Rules), CER (Canonical Encoding Rules), DER (Distinguished Encoding Rules), and PER (Packed Encoding Rules), it shall be encoded uniquely (converted to bit string (transfer syntax)). Can do. A processing system for performing the encoding and decoding of the encoding result is ASN. It can be easily configured by using a commercial / public domain software tool Snacc (Sample Neufeld Asn.1 to C Compiler) according to 1.

  ANS. For example, “Protocol Syntax Definition Language ASN.1”, cut system publication, etc., for example, ISO / IEC 8825-1: ASN.1 Encoding Rules, for coding rules BER, CER, DER, etc. : Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER), and Distinguished Encoding Rules (DER), etc., for encoding rules PER, for example, ISO / IEC 8825-1: ASN.1 Encoding Rules: Specification The details are disclosed in, for example, Packed Encoding Rules (PER).

  The event EventMessage is defined as follows, for example.

EventMessage :: = SEQUENCE {
formatVersion FormatVersion,
filteringMasks FilteringMasks OPTIONAL,
timeToLive UTCTime,
objectIdentifier ObjectIdentifier,
objectVersion INTEGER OPTIONAL,
subjectLinks SubjectLinks OPTIONAL
}

  Here, SEQUENCE {} indicates that the event (event type) EventMessage is represented by the sequence of variables formatVersion, FormatVersion, filteringMasks, timeToLive, objectIdentifier, objectVersion, subjectLinks defined in parentheses {}. . In addition, FormatVersion, FilteringMasks, UTCTime, ObjectIdentifier, INTEGER, and SubjectLinks arranged second from the left in parentheses {} indicate the types of variables arranged on the left. Also, OPTIONAL arranged third from the left in parentheses {} indicates that the variable defined in the line is an optional variable (an optional variable). Therefore, here, the event EventMessage includes at least a format version formatVersion, a lifetime timeToLive, and an object identifier objectIdentifier.

  Of the types FormatVersion, FilteringMasks, UTCTime, ObjectIdentifier, INTEGER, and SubjectLinks, INTEGER represents an integer, and UTCTime represents an international standard time or a local time (having at least a second precision). The definition of other types will be described later.

  In the event EventMessage, the format version formatVersion represents the format version of the event EventMessage. That is, considering that the format of the event EventMessage will be expanded in the future, the receiving terminal 5 needs to recognize the format in order to process the event EventMessage. The format version formatVersion is information (format information) for specifying the format of the event EventMessage, and the receiving terminal 5 recognizes and processes the format of the received event EventMessage by the format version formatVersion.

  The type FormatVersion of the format version formatVersion is defined as follows, for example.

FormatVersion :: = SEQUENCE {
majorVersion INTEGER,
minorVersion INTEGER
}

  That is, the format version formatVersion is represented here by two integers (INTEGER) called a major version majorVersion and a minor version minorVersion. The use of the major version majorVersion and minor version minorVersion and how to assign numbers can be arbitrarily defined by the operator of the data distribution system, but here, for example, the major version majorVersion contains an event And information for distinguishing the subject and the subject. That is, for example, a predetermined value or more is used as the major version majorVersion for the event, and less than a predetermined value is used as the major version majorVersion for the subject. In this case, the format version formatVersion represents the version of the format of the event EventMessage, and also serves as the determination flag described in FIG.

  Here, the information for discriminating the event from the subject can be defined in the major version majorVersion or in the upper layer of the transport layer, for example, the application layer or the presentation layer.

  The filter mask filteringMasks in the event EventMessage is information (selection criterion information) that can be used as a reference for selecting the event EventMessage in the receiving terminal 5, and the type FilteringMasks is defined as follows, for example. .

FilteringMasks :: = SEQUENCE OF {
filteringMaskIdentifier INTEGER,
filteringMaskField ANY DEFINED BY filteringMaskIdentifiler
}

  Here, SEQUENCE OF {} represents that the filter mask (type of filter mask filteringMasks) FilteringMasks is expressed by an ordered sequence of combinations of the variables filteringMaskIdentifier and filteringMaskField defined in parentheses {}. Therefore, the filter mask filteringMasks can be configured by arranging not only one combination of the variables filteringMaskIdentifier and filteringMaskField but also a plurality of combinations. In addition, the type ANY DEFINED BY of the variable filteringMaskField represents an arbitrary type (arbitrary type) depending on the variable arranged after BY. Therefore, the type of the variable filteringMaskField can take an arbitrary type corresponding to the variable filteringMaskIdentifiler arranged in the previous row.

  The mask identifier filteringMaskIdentifier in the filter mask filteringMasks is for identifying the mask field filteringMaskField. Here, a unique integer is used for each mask field filteringMaskField.

  The mask field filteringMaskField in the filter mask filteringMasks is information that can be used as a criterion for selecting an object corresponding to the event EventMessage (an object updated by a subject acquired based on the event EventMessage), For example, information related to the category of the object, age restrictions for viewing the object, contract contents for viewing the object, and the like are arranged.

  That is, in the mask field filteringMaskField, for example, information indicating that the object is related to sports or weather forecast is arranged, and further information that the object is related to sports is arranged. In this case, information representing whether the object is related to baseball or soccer in sports can be arranged. In this case, for example, a category desired by the user is set in the selection unit 22 in the receiving terminal 5 (the setting of the category may be performed by the user, for example. It is also possible to store the viewing history of an object and perform it based on the viewing history), and by comparing the category with the mask field filteringMaskField, only events corresponding to objects of the category desired by the user As a result, it is possible to receive only objects of a category desired by the user. Conversely, a category not desired by the user is set in the selection unit 22 in the receiving terminal 5, and the category is compared with the mask field filteringMaskField, thereby corresponding to an object of a category excluding the category not desired by the user. It is also possible to select only events to be performed.

  In addition, in the mask field filteringMaskField, for example, information regarding age restrictions such as how many years an object is intended can be arranged. In this case, for example, an age is set in the selection unit 22 of the receiving terminal 5, and the age is compared with the mask field filteringMaskField so that an event corresponding to an adult-oriented object is not selected. Is possible.

  Further, in the mask field filteringMaskField, it is also possible to arrange information related to the contract contents such as for users with contract contents paying a high contract fee or for users with contract contents paying a low contract fee. In this case, the contract content is set in the selection unit 22 in the receiving terminal 5, and the contract content is compared with the mask field filteringMaskField so that the object is selected according to the contract content when viewing the object. It becomes possible to make it.

  Here, as described above, the filter mask filteringMasks can be configured by arranging one or more combinations of the mask identifier filteringMaskIdentifier and the mask field filteringMaskField. It is possible to sequentially describe two mask fields filteringMaskField in which age restrictions are respectively arranged in combination with corresponding mask identifiers filteringMaskIdentifier. In this case, the selection unit 22 selects only events that belong to a predetermined category and correspond to an object for a predetermined age, or among an object that belongs to a predetermined category and an object for a predetermined age It is possible to select an object corresponding to any of the above. In this case, the selection unit 22 determines whether each of the two mask fields filteringMaskField arranged in the filter mask filteringMasks relates to the category of the object or to age restrictions when viewing the object. Recognized based on the corresponding mask identifier filteringMaskIdentifier.

  Further, the mask identifier filteringMaskIdentifier has a different value if the information arranged in the mask field filteringMaskField is different, but may be a different value even if the same information is arranged. That is, for example, when information related to the category of an object is arranged in the mask field filteringMaskField, the number of categories increases, and in order to express the increased category, it is necessary to increase the number of bits allocated to the mask field filteringMaskField. There is. Specifically, the mask field filteringMaskField may be increased to 16 bits, for example, from 8 bits at the beginning. In such a case, different mask identifiers filteringMaskIdentifier are associated with the 8-bit mask field filteringMaskField and the 16-bit mask field filteringMaskField. This is to enable the receiving terminal 5 to recognize the number of bits assigned to the mask field filteringMaskField.

  By arranging the filter mask filteringMasks as described above in the event EventMessage, the selection unit 22 can select the event EventMessage. As a result, even if the subject does not include the filter mask filteringMasks, the subject is discarded. Selection becomes possible. That is, since the subject is acquired based on the event EventMessage, by selecting the event EventMessage, the subject is also selected as a result. Furthermore, the selection of the object updated by the subject is also performed thereby.

  Next, the survival time (time limit information) timeToLive in the event EventMessage represents the expiration date of the event EventMessage. That is, in the receiving terminal 5, the event EventMessage transmitted via the broadcast network 4 is received. For example, in the receiving terminal 5, the received event EventMessage is temporarily stored in the database 23. It is not always processed immediately. For this reason, when attempting to perform the data request process of FIG. 11 for the event EventMessage, the event EventMessage may already be unavailable.

  That is, for example, when the subject broadcast time is arranged in the event EventMessage, the start time of the data request process in FIG. 11 may pass the broadcast time. In this case, even if the data request process of FIG. 11 is performed, since the subject has already been broadcast, the receiving terminal 5 cannot receive the subject. Therefore, storing such an unusable event EventMessage in the database 23 is a waste of storage capacity and is not preferable.

  Further, the event EventMessage can be transmitted to the receiving terminal 5 via the communication network 6 such as the Internet, as described above, in addition to being transmitted via the broadcast network 4 such as a satellite line. However, when the event EventMessage is transmitted via the communication network 6, the event EventMessage is received by the receiving terminal 5 due to the congestion (traffic) of the line after the transmission by the server 2. , After a considerable amount of time. Even in such a case, the event EventMessage may already be disabled.

  Therefore, the time to discard the event EventMessage is arranged in the survival time timeToLive as an index representing the freshness of the event EventMessage.

  In this case, in the receiving terminal 5, when the time when the event is received or the time when the event stored in the database 23 is referred has passed the time arranged in the lifetime timeToLive, the event cannot be used. (The received event is not stored in the database 23, and the referenced event is deleted from the database 23).

  In the server 2, the lifetime timeToLive is set as follows, for example. That is, the data configuration unit 17 of the server 2 obtains an average value of the update interval of the object corresponding to the event EventMessage (the time from the update of the object to the next update), etc., and an integer of the average value The time obtained by adding the time represented by the double to the creation time of the event EventMessage is arranged in the lifetime timeToLive. The setting method of the survival time timeToLive is not limited to this.

  Next, the object identifier objectIdentifier in the event EventMessage is information (position information) about the position where the object for which the event EventMessage notifies the update exists, and the receiving terminal 5 determines whether the updated object is based on the object identifier objectIdentifier. Identified and recognized. In the server 2, when an object in the database 3 is updated, an event EventMessage is created in response to the update of the object. Therefore, according to the object identifier objectIdentifier that identifies the updated object, the update is notified. Therefore, the object identifier objectIdentifier corresponds to the ID shown in FIG.

  The type ObjectIdentifier of the object identifier objectIdentifier is defined as follows, for example.

ObjectIdentifier :: = SEQUENCE {
avairableTime AvairableTime OPTIONAL,
locator Locator
}

  The obtainable time “availableTime” is a temporal position where the object notified of the update exists, that is, for example, the time when the updated object is registered in the database 3 or the time registered in the database 3 (object Represents the time during which the object is effectively present, such as the time from when the is updated until the next update. The obtainable time “availableTime” may or may not be described, and its type “AvairableTime” is defined as follows, for example.

AvairableTime :: = SEQUENCE {
startTime UTCTime,
endTime UTCTime OPTIONAL
}

  Here, the start time startTime represents, for example, the time when the updated object is registered in the database 3. Here, the end time endTime represents, for example, the time when the updated object is updated next. Note that when describing the obtainable time “availableTime”, the description of the start time “startTime” is indispensable, but the description of the end time “endTime” is optional (OPTIONAL).

  The locator locator in the object identifier objectIdentifier represents the geographical or logical position where the object for which the update is notified exists. Here, the geographical position of the object means information for specifying the position on the network such as the Internet address of the server 2 that manages the object. The logical position means the position of the object in the table or data structure when the object forms part of a certain table or data structure. Specifically, for example, when an object constitutes a column for introducing a television broadcast program in a certain time zone in a certain channel of an EPG (Electric Program Guide), The position becomes the logical position of the object.

  The type Locator of the locator locator is defined as follows, for example.

Locator :: = CHOICE {
netLocator NETLocator
dvbSpecificLocator DVBSpecificLocator
}

  Here, CHOICE {} means that one of the variables netLocator and dvbSpecificLocator defined in parentheses {} is selected (therefore, Locator is a selection type).

  The net locator netLocator specifies a domain resource accessible by the Internet protocol, and its type NETLocator is defined as follows, for example.

NETLocator :: = SEQUENCE {
nsapSpecificLocator NSAPSpecificLocator OPTIONAL,
universalResourceIdentifier EXTERNAL
}

  Here, EXTERNAL is ASN. This means that the data type is defined outside the scope of one module (external type). The definition does not have to follow the syntax of 1.

  The NSAP locator nsapSpecificLocator is used to specify an NSAP (Networks Service Access Point), and its type NSAPSpecificLocator is defined as follows, for example.

NSAPSpecificLocator :: = SEQUENCE {
nsapAddress EXTERNAL,
additionalInfo ANY OPTIONAL
}

  The NSAP address nsapAddress is an external type (EXTERNAL), and as its syntax, for example, E.164NSAPformat, ASAPA (Asynchronous Transfer Mode) End System Address (NSAPencodeE.164format), or the like can be adopted. The definition of E.164NSAPformat is described, for example, in ISO / IEC8348: Network Service Definition, and the definition of ASAPA NSAPencodeE.164format, for example, in ATM User-Network Interface (UNI) Specification 3.0 / 3.1. ing.

  Additional information additionalInfo is necessary when accessing the NSAP address nsapAddress, for example, protocol identification information indicating selection of PPP (Point to Point Protocol), information necessary for an authentication protocol, modem setting command sequence (haze) AT command) and the like, and its type is arbitrary (arbitrary type) (ANY). Note that the description of the additional information additionalInfo is arbitrary.

  The resource identifier universalResourceIdentifier in the net locator netLocator means a so-called URI (Universal Resource Identifier). The URI can uniquely identify a resource provided in the WWW, and is used when the user can directly connect to the Internet (when the receiving terminal 5 is directly connected to the Internet). Here, the syntax of the resource identifier universalResourceIdentifier is, for example, that defined in RFC1630: Universal Resource Identifiers in WWW: A Unifying Syntax for the Expression of Names and Addresses of Objects on the Network as used in the World-Wide Web. Can be used.

  As the net locator netLocator, both the URI and the NSAP locator nsapSpecificLocator can be used because, for example, they can be accessed by dial-up connection (including ATM connection) using X.25 or public networks. In order to be able to access objects in the Internet domain.

  The DVB locator dvbSpecificLocator in the locator locator specifies resources on the stream by digital broadcasting compatible with DVB (Digital Video Broadcasting), and the type DVBSpecificLocator is defined as follows, for example.

DVBSpecificLocator :: = CHOICE {
dvbPrimitiveLocator DVBPrimitiveLocator,
dvbDataCarouselLocator DVBDataCarouselLocator,
dvbObjectCarouselLocator DVBObjectCarouselLocator
}

  The primitive locator dvbPrimitiveLocator specifies a data structure / stream defined in DVB, and for example, can specify an arbitrary table on an EPG by digital broadcasting defined in DVB-SI. Therefore, in this case, the event EventMessage can also be used to update the contents of the EPG table broadcast in a format defined in DVB-SI, for example. Details of DVB-SI are described in, for example, ETC300 468: Digital broadcasting systems for television, sound and data services; Specification for Service Information (SI) in Digital Video Broadcasting (DVB) systems.

  The type DVBPrimitiveLocator of the primitive locator dvbPrimitiveLocator is defined as follows, for example.

DVBPrimitiveLocator :: = SEQUENCE {
networkID [0] INTEGER OPTIONAL,
transportStreamID [1] INTEGER OPTIONAL,
packetID [2] INTEGER OPTIONAL,
serviceID [3] INTEGER OPTIONAL,
tableID [4] INTEGER OPTIONAL,
tableIDExtention [5] INTEGER OPTIONAL,
sectionNumber [6] INTEGER OPTIONAL,
eventID [7] INTEGER OPTIONAL,
componentTag [8] INTEGER OPTIONAL
}

  Here, the parentheses [] and the numbers arranged therein are tags for identifying each of a plurality of variables of the same type constituting the structural type.

  For NetworkID, TransportID, packetID, serviceID, tableID, tableIDExtention, sectionNumber, eventID, componentTag, for example, ISO / IEC13818-1: Infomation technology-Generic coding of moving pictures and associated audio information-Part1: Systems-International Standard ( IS), and ETC300 468: Digital broadcasting systems for television, sound and data services; Specification for Service Information (SI) in Digital Video Broadcasting (DVB) systems. To do.

  The data carousel locator dvbDataCarouselLocator in the DVB locator DVBSpecificLocator specifies a data structure called a data carousel, and its type DVBDataCarouselLocator is defined as follows, for example.

DVBDataCarouselLocator :: = SEQUENCE {
dvbPrimitiveLocator DVBPrimitiveLocator,
groupID [0] INTEGER OPTIONAL,
moduleID [1] INTEGER OPTIONAL
}

  The object carousel locator dvbObjectCarouselLocator in the DVB locator DVBSpecificLocator specifies a data structure called an object carousel, and the type DVBObjectCarouselLocator is defined as follows, for example.

DVBObjectCarouselLocator :: = SEQUENCE {
dvbPrimitiveLocator DVBPrimitiveLocator,
carouselID [0] INTEGER OPTIONAL,
moduleID [1] INTEGER OPTIONAL,
objectKey [2] INTEGER OPTIONAL
}

  For data carousel, object carousel, groupID, moduleID, carouselID, and objectKey, for example, Digital Video Broadcasting: DVB Specification for Data Broadcasting-Final Draft 12/02/97, and Implementation Guidelines for Databroadcasting (SI-DAT382 Rev. 3 ), The details of which are described here, and the description thereof is omitted here.

  Next, the object version objectVersion in the event EventMessage represents the updated version of the object updated by the subject acquired based on the event EventMessage, and corresponds to the version information in FIG. As the object version objectVersion, for example, an integer value incremented every time the object is updated, a hash value of the updated object, or the like can be used.

  The subject link subjectLinks in the event EventMessage is for specifying the subject (subject for updating the object specified by the object identifier objectIdentifier) acquired based on the event EventMessage, and the type SubjectLinks is, for example, Is defined as follows.

SubjectLinks :: = SEQUENCE OF {
subjectIdentifier ObjectIdentifier,
subjectVersion INTEGER OPTIONAL,
qosSpecification QOSSpecification OPTIONAL,
clientIdentifer ClientIdentifier OPTIONAL
}

  The subject identifier subjectIdentifier has the same type ObjectIdentifier as the above-described object identifier objectIdentifier, and information (position information) regarding the position where the subject exists is arranged therein. Therefore, the receiving terminal 5 obtains a subject for updating the object based on the subject identifier subjectIdentifier.

  Since the subject identifier subjectIdentifier is an ObjectIdentifier type, it may have an obtainable time “availableTime”, which corresponds to the broadcast time in the broadcast schedule information described with reference to FIG. The subject identifier “subjectIdentifier” has a locator locator, which is the server access information (IP address of the server 2, etc.) (the geographical location of the subject) described in FIG. It corresponds to the logical position of the subject).

  The subject version subjectVersion is an integer type (INTEGER) and represents the version of the subject. That is, for example, a subject has a so-called bug, and a repaired subject may be newly created. Further, the subject content may remain the same, and the syntax may be changed. In such a case, the subject version subjectVersion is used in order to distinguish the subject before the bug correction from the subject after the modification, or to distinguish the subject before the syntax change from the subject after the change.

  In the service specification qosSpecification, information (acquisition determination criterion information) that can be used as a criterion for determining whether or not to acquire a subject based on the subject identifier subjectIdentifier is arranged. That is, since the subject link SubjectLinks is defined by SEQUENCE OF {}, one or more combinations of variables defined in parentheses {} are arranged. Specifically, for example, when a subject is broadcast via the broadcast network 4 and transmitted via the communication network 6 in response to a request from the receiving terminal 5 at the server 2, the broadcast network For each of the subject broadcast via 4 and the subject transmitted via the communication network 6, subjectIdentifier, subjectVersion, qosSpecification, and clientIdentifier defining the subject link SubjectLinks are described. In such a case, the service specification qosSpecification is referred to in order to determine which of the broadcast network 4 and the communication network 6 is used to receive the subject.

  The type QOSSpecification of the service specification qosSpecification is defined as follows, for example.

QOSSpecification :: = SEQUENCE OF {
qosSpecType INTEGER,
qosSpecValue INTEGER
}

  In the QOS type qosSpecType, an integer value representing the type of information used as a reference for determining whether or not to acquire a subject based on the subject identifier subjectIdentifier is arranged. That is, the QOS type qosSpecType indicates what value the QOS value qosSpecValue paired with the QOS type qosSpecType is.

  The QOS value qosSpecValue includes, for example, the status of the load applied to the server 2, the data amount of the subject, communication as information used as a criterion for determining whether or not to acquire a subject based on the subject identifier subjectIdentifier An integer value corresponding to the degree of congestion of the network 6 is arranged.

  For example, when the QOS value qosSpecValue indicates that the load applied to the server 2 side is large, if the subject is requested through the communication network 6, it takes time to send the subject. Since it is expected to be necessary, it can be used as a criterion for judging that it is better to wait for the broadcast to be received via the broadcast network 4. Also, for example, when the QOS value qosSpecValue indicates that the subject has a large amount of data, if the subject is requested via the communication network 6, the communication cost is required to receive the subject having a large amount of data. Therefore, it can be used as a criterion for determining that it is better to wait for the broadcast to be received via the broadcast network 4. Further, for example, when the QOS value qosSpecValue indicates that the traffic amount of the communication network 6 is small, it is expected that the subject can be acquired immediately and in a short time. It can be used as a criterion for determining that it is better to receive the data via the Internet.

  From the above, it can be said that the QOS value qosSpecValue represents the quality of the service provided by the subject.

  In the client identifier clientIdentifier in the subject link subjectLinks, information (user information) related to a user permitted to acquire the subject is arranged, and the type ClientIdentfier is defined as follows, for example.

ClientIdentifier :: = CHOICE {
clientGroupIdentifier INTEGER,
clientIdentifiers SET OF INTEGER
}

  In the group identifier clientGroupIdentifier, an integer value that identifies a group of a plurality of receiving terminals is arranged. According to the group identifier clientGroupIdentifier, only a plurality of receiving terminals specified by the group identifier can acquire the subject.

  In the client identifier clientIdentifiers, user IDs of one or more receiving terminals (user IDs described with reference to FIGS. 13 and 14) are arranged. According to the client identifier clientIdentifiers, only one or more receiving terminals specified thereby can acquire a subject. Note that SET OF INTEGER, which is the type of client identifier clientIdentifiers, represents a set of integer types (set type).

  As described above, according to the client identifier clientIdentifier, it is possible to limit the receiving terminals from which the subject is acquired. For example, it is possible to prevent the request of the subject from being concentrated on one server.

  As described above, a format for realizing an event on an arbitrary transport protocol is ANS. 1 is represented by an abstract syntax expression. For example, ASN. In the case of using the Snacc. 1 compliant commercial / public domain software tool, for example, the following file may be given as the input.

EventMessage DEFINITIONS :: =
BEGIN
EventMessage :: = SEQUENCE {
formatVersion FormatVersion,
filteringMasks FilteringMasks OPTIONAL,
timeToLive UTCTime,
objectIdentifier ObjectIdentifier,
objectVersion INTEGER OPTIONAL,
subjectLinks SubjectLinks OPTIONAL
}
FormatVersion :: = SEQUENCE {
majorVersion INTEGER,
minorVersion INTEGER
}
FilteringMasks :: = SEQUENCE OF {
filteringMaskIdentifier INTEGER,
filteringMaskField ANY DEFINED BY filteringMaskIdentifiler
}
ObjectIdentifier :: = SEQUENCE {
avairableTime AvairableTime OPTIONAL,
locator Locator
}
AvairableTime :: = SEQUENCE {
startTime UTCTime,
endTime UTCTime OPTIONAL
}
Locator :: = CHOICE {
netLocator NETLocator
dvbSpecificLocator DVBSpecificLocator
}
NETLocator :: = SEQUENCE {
nsapSpecificLocator NSAPSpecificLocator OPTIONAL,
universalResourceIdentifier EXTERNAL
}
NSAPSpecificLocator :: = SEQUENCE {
nsapAddress EXTERNAL,
additionalInfo ANY OPTIONAL
}
DVBSpecificLocator :: = CHOICE {
dvbPrimitiveLocator DVBPrimitiveLocator,
dvbDataCarouselLocator DVBDataCarouselLocator,
dvbObjectCarouselLocator DVBObjectCarouselLocator
}
DVBPrimitiveLocator :: = SEQUENCE {
networkID [0] INTEGER OPTIONAL,
transportStreamID [1] INTEGER OPTIONAL,
packetID [2] INTEGER OPTIONAL,
serviceID [3] INTEGER OPTIONAL,
tableID [4] INTEGER OPTIONAL,
tableIDExtention [5] INTEGER OPTIONAL,
sectionNumber [6] INTEGER OPTIONAL,
eventID [7] INTEGER OPTIONAL,
componentTag [8] INTEGER OPTIONAL
}
DVBDataCarouselLocator :: = SEQUENCE {
dvbPrimitiveLocator DVBPrimitiveLocator,
groupID [0] INTEGER OPTIONAL,
moduleID [1] INTEGER OPTIONAL
}
DVBObjectCarouselLocator :: = SEQUENCE {
dvbPrimitiveLocator DVBPrimitiveLocator,
carouselID [0] INTEGER OPTIONAL,
moduleID [1] INTEGER OPTIONAL,
objectKey [2] INTEGER OPTIONAL
}
SubjectLinks :: = SEQUENCE OF {
subjectIdentifier ObjectIdentifier,
subjectVersion INTEGER OPTIONAL,
qosSpecification QOSSpecification OPTIONAL,
clientIdentifer ClientIdentifier OPTIONAL
}
QOSSpecification :: = SEQUENCE OF {
qosSpecType INTEGER,
qosSpecValue INTEGER
}
ClientIdentifier :: = CHOICE {
clientGroupIdentifier INTEGER,
clientIdentifiers SET OF INTEGER
}
END

It is a figure which shows the structural example of one Embodiment of the data delivery system to which this invention is applied. It is a block diagram which shows the structural example of the server 2 of FIG. It is a block diagram which shows the structural example of the mirror server 7 of FIG. It is a flowchart for demonstrating the registration process which the server 2 performs. It is a figure which shows the format of the data supplied from the databases 1a thru | or 1c of FIG. It is a flowchart for demonstrating the data transmission process which the server 2 performs. It is a figure which shows the format of a subject and an event. It is a flowchart for demonstrating the request data transmission process which the server 2 performs. It is a block diagram which shows the structural example of the receiving terminal 5 of FIG. It is a flowchart for demonstrating the reception process which the receiving terminal 5 performs. It is a flowchart for demonstrating the data request process which the receiving terminal 5 performs. It is a flowchart for demonstrating the data output process which the receiving terminal 5 performs. It is a flowchart for demonstrating the load distribution process which the server 2 performs. It is a flowchart for demonstrating the access server determination process which the receiving terminal 5 performs.

Explanation of symbols

  1a to 1c database, 2 server, 3 database, 4 broadcast network, 5 receiving terminal, 6 communication network, 7 mirror server, 8 database, 11 communication control unit, 12 resource allocation unit, 13 data search unit, 14 replication management unit, 15 registration units, 17 data configuration units, 18 transmission units, 21 reception units, 22 selection units, 23 databases, 24 communication control units, 25 request units, 26 readout units, 27 output units, 28 operation units

Claims (2)

Receiving means for receiving content data of a broadcast program repeatedly transmitted in a data carousel method, and an event message for receiving the content data;
Storage means for storing the content data received by the receiving means;
Detecting means for detecting broadcast schedule information necessary for receiving the content data included in the event message received by the receiving means;
The reception start time of the content data, determining means for determining by referring to the broadcast time included in the broadcast schedule information detected by said detecting means,
Discarding the event message when the time when the broadcast time included in the broadcast schedule information is referred has passed the expiration date of the event message included in the event message received by the receiving unit And a receiving device. Receiving a broadcast program content data repeatedly transmitted in a data carousel method, and an event message for receiving the content data; and
Storing the content data received in the receiving step;
A detecting step for detecting broadcast schedule information necessary for receiving the content data included in the event message received in the receiving step;
A determination step of determining a reception start time of the content data with reference to a broadcast time included in the broadcast schedule information detected in the detection step ;
Discard the event message when the time when the broadcast time included in the broadcast schedule information is referred has passed the expiration date of the event message included in the event message received in the reception step And a receiving method.

Images