JPH1155257A - Data distribution method and data distortion system and host device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data distribution method for properly realizing a countermeasure at the time of a reception error in terminal equipment while maintaining an advantage simultaneous data transmission in a broadcast system from a host device to plural terminals. SOLUTION: Dummy data for measuring an error generation ratio are transmitted from a host device 2 through a satellite line to terminal 1, and error occurrence data indicating the error occurrence ratio in each terminal equipment 1 at the time of receiving the dummy data are up-loaded to the host device 2. In the host device 2, all distributable data whose error ratio upper limit exceeds the current error occurrence ratio are selected by referring to distribution schedule management data, and the data whose final distribution due data comes earliest are distributed as distribution data. That is, the proper distribution data corresponding to the receiving situation in the terminal equipment 1 can be distributed, and the improvement of the distribution efficiency from the point of view of the whole distribution processing is expected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and system for distributing data from a host device to a terminal device, and a host device effective for use in the data distribution system.

[0002]

2. Description of the Related Art
In a data distribution system in which service providing data required for providing a service executed in a terminal device is distributed from a host device, a communication line capable of bidirectional data distribution between the host device and the terminal device such as a telephone line. And distributed data from both parties via this communication line. The above-described service providing data is distributed from the host device, and predetermined data such as operation data is uploaded from the terminal device to the host device.

However, in a data distribution system in which new service providing data is distributed at relatively short intervals, as the number of terminal devices belonging to the system increases, the time required for data distribution increases.
In addition, since communication costs are also increased, it has been desired to reduce the distribution time and the cost of the entire system. For example, when data of a new song needs to be distributed to each terminal device every few days as in a so-called communication karaoke system, the number of times of distribution from the host device becomes extremely large, which is particularly desired.

On the other hand, for example, there is data distribution in a broadcasting format using a communication / broadcasting satellite, etc., which has a large communication capacity and can simultaneously transmit data to a plurality of receiving devices. Is preferred. In other words, when data transmission in such a broadcasting format is adopted, there is a demerit due to the characteristic of simultaneous transmission to an unspecified large number of “broadcasts”. For example, satellite communication can transmit the same data collectively compared to terrestrial communication such as telephone lines and dedicated lines, and can be transmitted over a wider area than terrestrial wireless communication such as mobile phones. It is also possible to transmit the same data at once.

[0005] However, depending on weather conditions such as rainfall, radio waves from communication satellites may not reach the satellite communication terminals on the ground, and normal distribution of data may not be possible. Therefore, conventionally, in the case of one-way satellite communication,
Assuming from the beginning that data as a satellite communication terminal cannot be received, a method of transmitting one data a plurality of times at different times has been considered. However, it is inefficient to transmit the same data a plurality of times when no error occurs or the error occurrence rate is low.

[0006] Further, a method is conceivable in which the satellite communication terminal transmits a reception result to the transmitting satellite communication uplink station when the data cannot be received by the satellite communication terminal, and the satellite communication uplink station transmits the data again. I have. Since this method retransmits only data having a reception error, the inefficiency caused by transmitting unnecessary data is eliminated. However, if a data reception error occurs in a certain terminal device, retransmission only for that terminal device will cause the same data to be retransmitted again to the terminal device that did not receive the reception error. Become. That is,
When transmitting data in a broadcast format to a plurality of terminal devices, the first transmission is efficient because data can be transmitted to many terminal devices at one time, but when there is a reception error, If data is transmitted in a broadcast format that can be simultaneously transmitted to an unspecified number of users only by the circumstances of one terminal device, on the contrary, an inefficient aspect may appear.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has an advantage of simultaneous transmission of data in a broadcast format from a host device to a plurality of terminal devices. It is an object of the present invention to provide a data distribution method for appropriately realizing a countermeasure in the case where the system is implemented, a system for realizing the distribution method, and a host device used in the system.

[0008]

Means for Solving the Problems and Effects of the Invention A data distribution method according to the present invention, which has been made to achieve the above object, comprises:
As set forth in claim 1, the host device and the plurality of terminal devices are connected from the host device to the terminal device via broadcast means capable of transmitting an unspecified number of simultaneous transmissions, and at least from the terminal device to the host device. A method for distributing predetermined distribution data from a host device to a terminal device in a data distribution system connected via communication means capable of uploading to the terminal device, wherein each terminal device transmits data distributed from the host device. Detects the state of occurrence of a reception error when receiving a message, and uploads the state of occurrence of the reception error to the host device via communication means. The host device adapts the distribution based on the state of occurrence of the reception error uploaded from each terminal device. Level is determined, and distribution data corresponding to the determined distribution conformance level is distributed to the terminal device side via the broadcasting means. To.

According to the present data distribution method, each terminal device detects a reception error occurrence status when receiving data distributed from the host device, and sends the reception error occurrence status to the host device via the communication means. Upload. Then, the host device that has acquired the reception error occurrence status uploaded from each terminal device determines the distribution adaptation level based on the reception error occurrence status, and broadcasts the distribution data according to the determined distribution adaptation level. Distribution to the terminal device side through the means.

[0010] As described above, when the distribution data is distributed from the host device to the terminal device, the transmission data is transmitted through the broadcasting means, so that the distribution data is individually transmitted to all the terminal devices. The advantage of transmitting large amounts of data simultaneously in a broadcast format can be obtained as compared with the case of transmitting. Therefore, it is very effective especially when one host device needs to distribute data for distribution to many terminal devices.

However, in the case of data transmission in the broadcast format, as described above, normal transmission cannot be performed due to factors such as weather conditions because of the characteristic of simultaneous transmission to an unspecified large number of “broadcasts”. And a reception error may occur in the terminal device. When a reception error occurs, for example, it is necessary to transmit the distribution data having the reception error again. In this case, the data distribution method of the present invention employs the following characteristic method. adopt.

That is, as described above, each terminal device detects a reception error occurrence status, and the host device to which the reception error occurrence status has been uploaded determines the distribution conformity determined based on the reception error occurrence status. The distribution data is distributed to the terminal device according to the level. More specifically, the distribution conformance level is set stepwise according to, for example, an error occurrence rate, and the distribution data is also set with importance and urgency based on the contents thereof. .

In this case, the importance of the distribution data is determined from the viewpoint that the intended purpose cannot be achieved without using the distribution data because there is no alternative means. For example, assuming a so-called communication karaoke system, in addition to the above-mentioned new karaoke performance data from the host device, there is also a system that distributes, for example, image data used as a background image, commercial data broadcasted during karaoke use, and the like. Conceivable. In this case, the karaoke performance data is of high importance because the karaoke itself cannot be used without that data, and must be finally delivered to the terminal device. Also, commercial data can be said to be of high importance because of sponsors and the like. On the other hand, in the case of image data used for a background image, it is often possible to substitute image data already possessed by the terminal device even without the image data, so do not particularly consider the importance to be high. Is also good. On the other hand, regarding urgency,
In the case of karaoke performance data, there is a demand to distribute so-called new songs as soon as possible, so in such a situation, the urgency is high. On the other hand, even if the karaoke performance data is the same, if urgent karaoke performance data is created for the purpose of increasing the number of songs that can respond to the request, the urgency is not particularly high. In addition, the urgency of commercial data is high if the data has a limited time period, and the urgency is low if the data can be distributed within one month.

As described above, the degree of importance and the degree of urgency differ depending on the type and content of the distribution data. However, it is necessary to reliably distribute the distribution data with a high degree of importance to the terminal device.
It is preferable that the distribution is performed in a situation where a reception error is minimized. For this reason, the level suitable for distribution of distribution data with high importance is set to correspond to a situation in which a reception error is minimized. Then, as the degree of importance decreases, distribution in a situation where a certain amount of reception error occurs may be allowed. Therefore, a level suitable for such distribution of distribution data is set.

As a specific example which is easy to understand, the distribution conformance level is set to 1 to 5 and the allowable error occurrence rate is set to 1 for each.
%, 3% or less, 5% or less, 10% or less, 20% or less. The distribution data is not distributed unless the distribution conformance level is 1 in accordance with the degree of importance, the distribution data is permitted if the distribution conformance level is 3, and the distribution level is 5 in accordance with the importance.
However, settings such as those that allow distribution are made.

In terms of the degree of urgency, if the degree of urgency is low, there is no need to force distribution in a situation where the error occurrence rate is high. I do. Conversely, if the urgency is high,
Even if the error occurrence rate is high, level 5 is set if distribution is desired. However, when both importance and urgency must be considered, it is necessary to consider which of them has priority. That is, in the case of distribution data having a low degree of urgency but a high degree of importance, it is considered preferable to distribute only in a situation where the error occurrence rate is low, and 1 is set as a result at the above-mentioned distribution conformance level. On the other hand, if there is distribution data of normal importance but of high urgency, it is assumed that distribution data is desirably distributed to a terminal device which can distribute anyway even if an error occurs to some extent. In that case, priority is given to the degree of urgency, and level 5 is set for distribution even if the error occurrence rate is high.

In this way, appropriate distribution data can be distributed according to the reception status at the terminal device at each time, and unnecessary distribution when the entire distribution processing is viewed is reduced.
The distribution efficiency can be improved. In other words, the present data distribution method has the advantage of transmitting data in a broadcast format from the host device to a plurality of terminal devices at the same time, predicts the possibility of occurrence of a reception error in the terminal device, and provides an appropriate data By realizing the distribution, the distribution efficiency can be improved.

In the above data distribution method,
As described in claim 2, the host device distributes predetermined reception error detection data to the terminal devices prior to the distribution of the distribution data, and each terminal device receives the reception error detection data distributed from the host device. It is also possible to detect a reception error occurrence state when receiving data and upload the reception error occurrence state.

In this way, when the distribution data is to be distributed, the distribution suitability can be determined based on the reception error occurrence status obtained immediately before, and the distribution data according to the distribution conformance level is distributed. can do. Therefore, it is possible to realize distribution that is more suited to the situation at the time of distribution.
Of course, instead of distributing the reception error detection data prior to the distribution of the distribution data, the distribution conformance level is determined based on the reception error occurrence status corresponding to the previous distribution of the distribution data. It may be.
In other words, the method of distributing the reception error detection data prior to the distribution of the distribution data assumes that the distribution of the distribution data is performed a plurality of times with a certain interval period. Therefore, if your distribution happens almost continuously,
It is also conceivable to adopt a method based on a reception error occurrence state corresponding to the distribution of the distribution data up to the previous time.

Further, in these data distribution methods, a method according to claim 3 may be adopted. That is, the host device is assumed to execute distribution based on a predetermined distribution schedule, changes the distribution schedule based on the determined distribution conformance level, and transmits distribution data to the terminal based on the changed distribution schedule. It is distributed to the device side.

In this case, for example, if the distribution conformance level in the above-mentioned example is 1, and any distribution data can be distributed, distribution is performed according to the distribution schedule set first. . If the distribution conformance level becomes 3 on the way and the data to be distributed according to the distribution schedule at that time cannot be distributed unless the distribution conformance level is 1, the distribution is scheduled to be performed thereafter. Distribution conformance level of 3 data
However, it is only necessary to perform control such as replacement with an acceptable one.

On the other hand, as a system for realizing the above-described data distribution method, for example, the configuration shown in claim 4 can be considered. That is, the host device and the terminal device are connected from the host device to the terminal device side via broadcast means capable of simultaneously transmitting an unspecified number of devices, and at least communication means capable of uploading from the terminal device to the host device. A data distribution system for distributing predetermined distribution data from the host device to the terminal device, wherein each terminal device includes a receiving unit that receives data distributed from the host device, Detecting means for detecting a reception error occurrence state when data is received by the means, and upload control means for uploading the reception error occurrence state detected by the detection means to the host device via the communication means; The host device determines a distribution conformance level based on a reception error occurrence situation uploaded from each terminal device. And the step, characterized in that it includes a delivery control means for delivering to the terminal apparatus via a broadcast means distribution data corresponding to the determined distribution adapted level by the determining means.

In each terminal device of the data distribution system,
The data received from the host device is received by the receiving means, and the detecting means detects a reception error occurrence situation. Then, the upload control means uploads the reception error occurrence status to the host device via the communication means. Then, in the host device that has acquired the reception error occurrence status uploaded from each terminal device, the determination unit determines the distribution adaptation level based on the reception error occurrence status, and the distribution control unit determines the determined distribution adaptation level. Is distributed to the terminal device side via the broadcasting means.

In this data distribution system as well, the distribution control means of the host device distributes predetermined reception error detection data to the terminal device prior to distribution of the distribution data. And the detecting means of each terminal device is configured to detect a reception error occurrence state when receiving the reception error detection data distributed from the host device, or as described in claim 6. The delivery control means of the host device is configured on the assumption that the delivery is performed based on a predetermined delivery schedule, the delivery schedule is changed based on the determined delivery conformance level, and the delivery schedule is changed based on the changed delivery schedule. The distribution data may be configured to be distributed to the terminal device side.

The effects of these data distribution systems are the same as those described in the data distribution method described above, and will not be described here. On the other hand, as the broadcasting means, for example, a broadcasting form using satellite communication can be considered, and as the communication means, a communication form using a telephone network, an ISDN network, or the like can be considered. Of course, the broadcasting means may be a so-called terrestrial broadcasting form, but in the case of a broadcasting form using satellite communication, it has a large communication capacity,
This is effective because a large amount of data can be transmitted to a plurality of receiving devices at the same time.

The communication means may be a means for transmitting data in a broadcast format that allows simultaneous transmission to an unspecified number of people. Since what is performed via the communication means is uploading from the terminal device to the host device, generally, the communication form using the above-described telephone network or ISDN network, that is, data between a specific partner and Communication is conceivable, but if it is possible to achieve the intended purpose, it may be data communication with an unspecified partner, but may be in a broadcast format.

However, when the upload from the terminal device to the host device is performed through such a communication device of the broadcast format, the broadcast device used for data transmission from the host device to the terminal device side and the host device transmits the data from the terminal device to the host device. It is preferable that both communication means for transmitting data in a broadcast format used for transmitting data to the apparatus use satellite communication via the same satellite. This is because, in the case of the broadcast format, the burden tends to be generally large in terms of equipment or cost. In other words, when data distribution from the host device to the terminal device is performed via broadcasting means, for example, a transmitting parabolic antenna is required on the host device side, and a receiving parabolic antenna is required for each terminal device. There is a possibility that the cost, including fees, will be large. Accordingly, if the upload from the terminal device to the host device is performed via the communication means of the broadcast format and the satellite communication is performed via the same satellite, only the configuration in which the host device and the parabolic antenna of the terminal device can transmit and receive both is performed. Therefore, disadvantages in terms of equipment or cost can be mitigated.

On the other hand, the host device used in such a system can be configured as follows. For example, the host device described in claim 7 is connected to the terminal device side via broadcast means capable of transmitting an unspecified number of devices simultaneously,
A host device connected via at least a communication unit capable of uploading from the terminal device and capable of distributing predetermined distribution data to the terminal device, and detecting a reception error occurrence state when receiving the data; A determination unit that determines a distribution conformance level based on the reception error occurrence situation uploaded from each of the possible terminal devices; and the broadcasting unit that transmits the distribution data according to the distribution conformance level determined by the determination unit. And a distribution control means for distributing the information to the terminal device via the terminal device.

Also in this host device, the delivery control means may be configured to deliver predetermined reception error detection data to the terminal device prior to delivery of the delivery data. Alternatively, as set forth in claim 9, it is assumed that the distribution control means executes distribution based on a predetermined distribution schedule, and changes the distribution schedule based on the determined distribution conformance level.
The distribution data may be configured to be distributed to the terminal device based on the changed distribution schedule.

The operations and effects of these host devices have been described in the description of the data distribution method and system described above, and will not be repeated here. Of course, in realizing the data distribution system of the present invention, the present invention is not limited to this host device, but uses a device different from the above-described device as long as its purpose, operation, and effect are common. Needless to say, it also includes

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a data distribution system as one embodiment of the present invention. This data distribution system includes one host device 2 as a “host device” and a plurality of terminal devices 1 as a “terminal device”, and a “communication unit” via a public line 50. Two types of data distribution of “broadcasting means” via the satellite 30 are possible. Then, when the data is transmitted via the public line 50, the terminal device 1 can be specified and transmitted from the host device 2.
For example, if the public line 50 is a telephone line, the host device 2
By designating the telephone number of the terminal device 1 and making a call, connection to the desired terminal device 1 can be realized. On the other hand, when passing through the satellite 30, data can be simultaneously transmitted to an unspecified number of terminal devices 1 in a so-called broadcast format.

First, the terminal device 1 will be described. FIG.
2 is a block diagram showing an internal configuration of the terminal device 1. FIG. As shown in FIG. 2, the terminal device 1 includes a modem 13 for performing data communication with the host device 2 through a public line 50,
RAM as temporary storage means used for temporarily storing data fetched via the modem 13
12 and a tuner 15 connected to a parabolic antenna 110 for receiving a satellite broadcast wave broadcast from the host device 2 via a satellite 30, and for separating multiplexed data from the satellite broadcast wave. And a demodulator 14 for demodulating data. The data demodulated by the demodulator 14 is stored in the HDD 16 as storage means.

The data stored in the HDD 16 is M
Assuming that the image data is compressed based on the PEG2 video encoding method, the terminal device 1 of the present embodiment
A remote control light receiving unit 18 for receiving a request from a remote control 112 from a user, and a decoder 1 for decoding MPEG2 data stored in the HDD 16
7 is provided. The image data decoded by the decoder 17 can be displayed and output on a CRT 111 as display means.

The parabolic antenna 110, tuner 15, and demodulator 14 correspond to "receiving means". Also,
The data demodulated by the demodulator 14 is stored in the HDD 16 via the CPU 10, and an error is detected at this time. In the present embodiment, data is received in frame units, and error detection is performed in frame units. As a method of detecting an error, for example, a check sum method is used. When an error is detected in this error detection, the error occurrence rate is calculated and uploaded to the host device 2 as error occurrence situation data. Therefore, CPU1
0 corresponds to “detection means” and “upload control means”.

Next, the host device 2 will be described. FIG. 3 is a block diagram showing the internal configuration of the host device 2. The host device 2 communicates with the terminal device 1 through the public line 50.
23 for performing data communication with the terminal device 1
HDD 26 as storage means for storing data to be delivered to CPU 20, CPU 20 as control means for executing control of the entire apparatus, ROM 21 for storing a program to be executed by CPU 20, and temporary storage means A RAM 22 storing distribution schedule management data as shown in FIG. 4, a transmission control device 24 for performing control for transmitting data over a satellite line, and a modulation of the data to a satellite broadcast wave. And a modulator 25 for multiplexing. Then, the satellite broadcast wave modulated by the modulator 25 is transmitted to the satellite 30 by the parabolic antenna 210.

It should be noted that the CPU 20 corresponds to “determining means”, and in addition to the CPU 20, the transmission control device 24 and the modulator 25
And the parabolic antenna 210 correspond to “distribution control means”. Next, the distribution schedule management data stored in the RAM 23 will be described with reference to FIG.

As the distribution schedule management data, four data items are set for each of the identification numbers 1 to n of the distribution schedule data: the first date of the distribution period, the last date of the distribution period, the upper limit of the distributable error rate, and the lower limit of the redelivery required reception rate. I have. A supplementary explanation of these data will be given. First, a period in which the data is to be distributed is determined based on data on the first day of the distribution deadline and the last day of the distribution deadline. In other words, it is only necessary to perform distribution within this period. Therefore, for example, if the distribution is performed on the first day of the period but the reception status is not good and it becomes necessary to distribute again, the distribution may be performed again within the period such as the second or third day of the period. On the other hand, for example, when the first day of the distribution expiration date and the last day of the distribution expiration date are the same, distribution must be performed during that one day. Therefore, for example, if there is a distribution timing three times a day, such as morning, afternoon, and night, if the distribution is performed in the morning but the reception status is not good and it is necessary to distribute again, the distribution is performed in the afternoon or the day of the day. Must be delivered at night.

The upper limit of the error rate that can be distributed indicates the upper limit of the reception error rate at which data distribution is permitted.
In other words, if this upper limit is, for example, 1%, distribution is not permitted unless there is almost no reception error. If the upper limit is, for example, 10%, 10% is distributed even if the reception is not appropriate. You can do it. The upper limit of the distributable error rate is set according to the importance according to the content of the distribution data and the like. That is, when the importance is relatively high, the allowable reception error rate is set low, and when the importance is relatively low, the allowable reception error rate is set high.

On the other hand, the lower limit of the required re-delivery reception rate indicates the lower limit at which the distribution must be performed again if the reception success rate is lower than this. For example, if there is data that must be reliably delivered to all terminal devices 1, the lower limit of the required re-delivery reception rate for this data is 100
%. For example, if there is sufficient data to be able to be distributed to about 90% of the terminal devices 1, the lower limit of the required re-delivery reception rate for this data is 90%. That is, the lower limit of the required re-delivery reception rate is set according to the degree of importance or the degree of urgency according to the contents of the distribution data.

The upper limit of the distributable error rate and the lower limit of the redelivery required reception rate will be further described with specific data types. For example, assume that the terminal device 1 is a so-called karaoke terminal, and the host device 2 distributes karaoke performance data of a new song, image data used as a background image, commercial data broadcast during use, and the like. I do.

Since the karaoke performance data cannot be used for karaoke without the data, the karaoke performance data is highly important, and must be finally delivered to the terminal device 1. Therefore, for example, it is conceivable to set the upper limit of the deliverable error rate to 1% and the lower limit of the redelivery required reception rate to 100%. However, if the upper limit of the deliverable error rate is set to 1% and such a situation does not readily occur, the delivery cannot be performed forever. Accordingly, for example, the upper limit of the deliverable error rate is 10%, and the lower limit of the redelivery required reception rate is 100%.
It can be considered. By doing so, it is possible to realize that the content is distributed to all terminal devices 1 while being distributed as early as possible.

Further, commercial data is also highly important because of sponsors and the like, and must be finally delivered to the terminal device 1. Therefore, similarly to the karaoke performance data described above, it is conceivable to set the lower limit of the redelivery required reception rate to 100%. If the user wants to distribute to the terminal device 1 as early as possible, the upper limit of the distributable error rate may be set low, and the period from the first day of the distribution period to the last day of the distribution period may be set short.

On the other hand, in the case of image data used for a background image, image data already possessed by the terminal device 1 can often be substituted without the image data, so that urgency and importance are particularly high. You do not have to think too high. Therefore, if it is desired to distribute to as many terminal devices 1 as possible without being concerned with urgency, for example, the upper limit of the distributable error rate may be set to 1%. If the terminal device 1 that does not finally have the image data may be generated, the lower limit of the required redelivery reception rate is, for example, 90%, 80%, or 7%.
It may be set to 0% or less.

As described above, from the viewpoints of the importance and urgency of data, and whether or not the data can be replaced, the above-described first four days of the delivery deadline, the last day of the delivery deadline, the upper limit of the deliverable error rate, and the lower limit of the redelivery required reception rate are described. It is sufficient to set two data. The present data distribution system transmits data to the terminal device 1 via a satellite line, which has an advantage of simultaneous transmission of large amounts of data in a broadcast format. Therefore, normal transmission cannot be performed due to factors such as weather conditions, and a reception error may occur in the terminal device 1. When a reception error occurs, for example, it is necessary to retransmit the distribution data having the reception error, but in this case, for example, the distribution data having a high importance is configured to minimize the reception error. The distribution is controlled in such a manner that the distribution is performed in a situation and the distribution in a situation in which a certain number of reception errors occur as the importance becomes lower is permitted. Thus, it is possible to appropriately cope with a reception error in the terminal device while having the advantage of simultaneous transmission of a large amount of data in a broadcast format.

The data distribution and reception processing in the data distribution system will be described with reference to the drawings. In addition,
The flowchart of FIG. 5 shows the data distribution control processing in the host device 2, and the flowchart of FIG.
2 shows a data reception process. During the data distribution process executed by the host device 2, there is a portion to be executed based on the data uploaded from the terminal device 1. Therefore, the data reception process will be appropriately described while proceeding mainly with the data distribution process. Will be explained on the way.

As shown in FIG. 5, in the first step S110 of the data distribution control process in the host device 2, dummy data for measuring the error occurrence rate is transmitted over a satellite line a fixed time before the scheduled distribution time. . When transmitting data over a satellite line, the data is transmitted to the transmission control device 2
The data is transferred to the modulator 25 through the modulator 4, and the data is modulated by the modulator 25 and multiplexed with satellite broadcast waves. The satellite broadcast wave modulated by the modulator 25 is transmitted to the satellite 30 by the parabolic antenna 210 and transmitted to the terminal device 1 in the form of broadcast.

On the other hand, when the process of transmitting the dummy data to the terminal device 1 (S110) is performed, the following process is performed in the terminal device 1. That is, in the first step S310 of the data receiving process shown in FIG. 7, dummy data for error rate measurement transmitted from the host device 2 via the satellite line from a predetermined time before the scheduled distribution time is received. A satellite broadcast wave in which data is multiplexed is transmitted from the satellite 30, but is transmitted simultaneously to an unspecified number of terminal devices 1 because this is a broadcast wave. Therefore, if the terminal device 1 is ready to receive, the signal is appropriately received via the parabolic antenna 110, the tuner 15 and the demodulator 14, and demodulated by the demodulator 14. And S320
Then, the status of data reception is monitored, but monitoring is performed until a predetermined monitoring time ends (S330: YES). The predetermined monitoring time indicates a time sufficient for the terminal device 1 to receive the dummy data transmitted from the host device 2 via the satellite line based on the size of the dummy data and the like.

When the monitoring time ends (S33)
0: YES), in S340, it is determined whether or not a reception error has occurred in the received and demodulated dummy data, and the error occurrence rate is calculated. As mentioned above,
In the present embodiment, data is received in units of frames, and error detection is performed in units of frames. As a method of detecting an error, for example, a check sum method is used. Then, when an error is detected in the error detection, an error occurrence rate is calculated.

After the error occurrence rate is calculated in S340, predetermined data including the error occurrence rate is transmitted to the host device 2 as error occurrence situation data at the time of reception in S350. The data transmission to the host device 2 is performed via the public line 50.

Returning to the description of the data distribution processing in the host device 1 of FIG. 5, when the dummy data distribution processing in S110 described above is completed, in subsequent S120, the error occurrence situation data relating to the dummy data from the terminal device 1 is collected. Then, in S130, the error occurrence situation data is actually received. This data reception processing is performed until the predetermined collection time ends (S140: YES). The predetermined collection time is the time when all the terminal devices 1 that are to upload the error occurrence status data transmit the error occurrence status data and the host device 2 can receive all the error occurrence status data. It is.

When the collection time ends (S140: YE
In S) and S150, the received error occurrence status data is totalized, and the current error occurrence rate is calculated.
That is, the error occurrence rate in the entire system is calculated by averaging the error occurrence rates of the plurality of terminal devices 1 or the like.

In S160, referring to the delivery schedule management data (see FIG. 4), all the delivery data whose upper limit of the deliverable error rate exceeds the current error occurrence rate obtained from the aggregation result in S150. Pick out. However, it is assumed that there is no corresponding distribution data.
In S170, it is determined whether or not there is the corresponding data. If there is no corresponding data (S170: NO), the present data distribution process is terminated.

On the other hand, if there is the corresponding data (S170: Y
ES), from among the distribution data selected in S160, one having the earlier distribution deadline is selected (S18).
0). When there are two or more items having the same distribution deadline last date, for example, one having smaller identification numbers 1 to n may be selected.

After one distribution data is selected in S180, the process proceeds to S190, and when the scheduled distribution time comes,
The distribution of the selected distribution data is started. In addition,
This distribution data is distributed via a satellite line. on the other hand,
When the process of transmitting the distribution data to the terminal device 1 in S180 is performed, the following process is performed in the terminal device 1. That is, S36 of the data receiving process shown in FIG.
As shown at 0, the actual distribution data transmitted at the scheduled distribution time is received. This reception processing is performed through the parabolic antenna 110, the tuner 15, and the demodulator 14 in the same manner as the dummy data described above.
Demodulation is performed. Then, in S370, the status of data reception is monitored, and whether or not the distribution data has been correctly received is transmitted to the host device 2 as a reception result, and the data reception process ends. Returning to the description of the data distribution processing in the host device 1 in FIG.
After the start of the distribution of the distribution data in step S200 (see FIG. 6)
Move to In S200, collection of reception result data on distribution data from the terminal device 1 is started, and in S210, the reception result data is actually received. This data reception processing is performed until a predetermined collection time ends (S220: Y
ES) Perform. The predetermined collection time is a time at which a sufficient time has elapsed for all the terminal devices 1 that are to upload the reception result data to transmit the reception result data and for the host device 2 to receive all the reception result data. .

When the collection time ends (S220: YE)
S), In S230, the received reception result data is totalized. Then, in S240, with reference to the distribution schedule management data (see FIG. 4), whether the reception success rate calculated based on the aggregation result in S230 exceeds the lower limit of the redelivery required reception rate corresponding to the distribution data. Judge whether or not. If the reception success rate exceeds the lower limit of the required redelivery reception rate (S240: YES), the process proceeds to S250 and deletes the distributed data from the distribution schedule list in the distribution schedule management data (see FIG. 4). . on the other hand,
If the reception success rate does not exceed the lower limit value of the required re-delivery reception rate (S240: NO), the data distribution processing ends.

For example, if the actual reception success rate is 95%,
When the lower limit of the required redelivery reception rate is 90%, redelivery is unnecessary. Therefore, by shifting to S250 and deleting from the distribution schedule list, distribution is not performed at the next data distribution. On the other hand, for example, when the actual reception success rate is 85% and the lower limit of the redelivery required reception rate is 90%, redelivery is necessary. Therefore, the process of deleting from the distribution schedule list in S250 is not executed, and the process ends. As a result, the data is included in the distribution schedule list also at the time of the next data distribution, and thus becomes a distribution candidate.

The transmission control process from the host device 2 and the reception process at the terminal device 1 have been described above. FIG. 8 is a sequence diagram showing the flow of data related to such data distribution. In FIG. 8, the dummy data is transmitted, the reception result is uploaded from each terminal device 1, the distribution data is selected based on the reception result, and the time until the selected distribution data is transmitted is shown. Naturally, the result of receiving the distribution data from each terminal device 1 is also uploaded again.

As described above, in the data distribution system according to the present embodiment, it is premised that data is distributed from the host device 2 to the terminal device 1 by multiplexing the data with a satellite broadcast wave through a satellite line. The advantage of simultaneous transmission of large amounts of data in a broadcast format can be obtained as compared with the case where data is individually transmitted to all terminal devices 1. Therefore, it is very effective in a system in which one host device 2 needs to distribute data to many terminal devices 1.

However, in the case of data transmission in the broadcast format, normal transmission cannot be performed due to factors such as weather conditions due to the characteristic of simultaneous transmission to an unspecified large number of "broadcasts". May cause a reception error. In that case, it is necessary to have the reception result uploaded from the terminal device 1 and to retransmit the data with the reception error, so that, for example, it is necessary to finally distribute the data to all the terminal devices 1. For certain distribution data, distribution processing must be performed many times.

Therefore, in the present embodiment, first, the host device 2 transmits dummy data for measuring the error occurrence rate to the terminal device 1, and an error in each terminal device 1 when the dummy data is received. The error occurrence status data indicating the occurrence rate is uploaded to the host device 2.
Then, the host device 2 refers to the distribution schedule management data (see FIG. 4) and selects all the distribution data in which the upper limit of the distributable error rate exceeds the current error occurrence rate. Distribute earlier data as distribution data.

In this way, for example, distribution data having a high degree of importance and which must be reliably distributed to all the terminal devices 1 is distributed in a situation where a reception error is minimized, Although the degree is not so high, if it is desired to distribute as early as possible, it is possible to realize distribution even in a situation where some reception error occurs. That is, it is possible to distribute appropriate distribution data according to the reception status of the terminal device 1 at each time, and it is possible to reduce unnecessary distribution when the entire distribution processing is viewed, and to improve distribution efficiency. That is, while having the advantage of simultaneous transmission of data in a broadcast format from the host device 2 to the plurality of terminal devices 1, the possibility of occurrence of a reception error in the terminal device 1 is predicted, and appropriate data distribution corresponding thereto is realized. By doing so, the distribution efficiency can be improved.

As described above, the present invention is not limited to such embodiments at all, and can be implemented in various forms without departing from the gist of the present invention. For example, in the above embodiment, the host device 2 transmits the dummy data before distributing the distribution data, grasps the error occurrence status, and selects the distribution data according to the error occurrence status. The next distribution data may be selected based on an error occurrence situation when the distribution data is actually distributed. However, considering that the error occurrence situation changes due to factors such as weather conditions, the effect is diminished in the error occurrence situation grasped immediately before the scheduled delivery time of the original distribution data. Therefore, for example, in a system in which data distribution is performed every eight hours and one data distribution is completed in about one hour, a method of first grasping an error occurrence state using dummy data as in the above-described embodiment. Is preferred. On the other hand, for example, data is distributed every hour,
In a system in which one data distribution is completed in about 50 minutes, it is more realistic to select the next distribution data based on an error occurrence state at the time of the previous data distribution.

In the above embodiment, the HDDs 16 and 26 are assumed to store the image data in the host device 2 or the terminal device 1. However, it may be a video server unit. In other words, HD
D and a control unit for controlling these HDDs, and read and write image data in accordance with instructions from CPUs 10 and 20.

In the above-described embodiment, the transmission control device 24, the modulator 25, and the parabolic antenna 210 are provided so that the host device 2 itself can perform distribution via a satellite line. However, these components are not provided. The system may be configured as a host device, for example, connected to a separately provided satellite relay base station via a dedicated communication line, and actually transmit distribution data to the satellite relay base station for distribution.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a data distribution system according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of a terminal device according to the embodiment.

FIG. 3 is a block diagram illustrating a configuration of a host device according to the embodiment.

FIG. 4 is an explanatory diagram showing distribution schedule management data stored in a RAM of the host device of the embodiment.

FIG. 5 is a flowchart illustrating a part of a data distribution process executed in the host device of the embodiment.

FIG. 6 is a flowchart illustrating a part of a data distribution process executed in the host device of the embodiment.

FIG. 7 is a part of a flowchart showing an operation relating to a data reception process executed in the terminal device of the embodiment.

FIG. 8 is a sequence diagram illustrating a data flow between the host device and the terminal device according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Terminal device 2 ... Host device 10 ... CPU 12 ... RAM 13 ... Modem 14 ... Demodulator 15 ... Tuner 16 ... HDD 20 ... CPU 22 ... RAM 23 ... Modem 24 ... Transmission control device 25 ... Modulator 26 ... HDD 30 ... Satellite 50 Public line 110 Parabolic antenna 210 Parabolic antenna

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification symbol FI // H04N 7/16 H04N 7/16 E

Claims (9)

[Claims] 1. A host device and a plurality of terminal devices are connected to the terminal device side from the host device via a broadcast means capable of simultaneously transmitting an unspecified number of devices, and at least from the terminal device to the host device. In a data distribution system connected via an uploadable communication means, a method for distributing predetermined distribution data from the host device to a terminal device, wherein each of the terminal devices is distributed from the host device. Detecting the reception error occurrence situation when receiving the received data, uploading the reception error occurrence situation to the host device via the communication means, the host device generates a reception error occurrence uploaded from each of the terminal devices. Determining a distribution conformance level based on a situation, and transmitting the distribution data according to the determined distribution conformance level to the broadcast unit; Data distribution wherein the delivery to the terminal apparatus via. 2. The host device distributes predetermined reception error detection data to a terminal device prior to distribution of the distribution data, and each of the terminal devices detects a reception error distributed from the host device. 2. The data distribution method according to claim 1, further comprising: detecting a reception error occurrence state when receiving the use data, and uploading the reception error occurrence state. 3. The host device is supposed to execute distribution based on a predetermined distribution schedule. The host device changes the distribution schedule based on the determined distribution conformance level, and based on the changed distribution schedule. The data distribution method according to claim 1, wherein the distribution data is distributed to the terminal device side. 4. A host device and a terminal device are connected from the host device to the terminal device via broadcast means capable of transmitting an unspecified number of simultaneous transmissions, and at least uploading from the terminal device to the host device is possible. A data distribution system for communicating predetermined distribution data from the host device to the terminal device, wherein each of the terminal devices includes data distributed from the host device. Receiving means for receiving data, detecting means for detecting a reception error occurrence situation when data is received by the receiving means, and receiving error occurrence status detected by the detection means via the communication means to the host device. Upload control means for uploading to the host device, while the host device generates a reception error uploaded from each of the terminal devices. A determination unit that determines a distribution conformance level based on a situation; and a distribution control unit that distributes the distribution data according to the distribution conformance level determined by the determination unit to the terminal device via the broadcast unit. A data distribution system, comprising: 5. The distribution control unit of the host device is configured to distribute predetermined reception error detection data to a terminal device prior to the distribution of the distribution data, and the detection unit of each of the terminal devices comprises: 5. The data distribution system according to claim 4, wherein the data distribution system is configured to detect a reception error occurrence state when receiving reception error detection data distributed from the host device. 6. The distribution control means of the host device is supposed to execute distribution based on a predetermined distribution schedule, changes the distribution schedule based on the determined distribution conformance level, and changes the distribution schedule. The data distribution system according to claim 4, wherein the distribution data is configured to be distributed to the terminal device based on a distribution schedule. 7. The terminal device is connected to the terminal device via broadcasting means capable of simultaneously transmitting to an unspecified number of users, and is connected at least via communication means capable of uploading from the terminal device. A host device capable of distributing predetermined distribution data to the host device, and based on the reception error occurrence status uploaded from each of the terminal devices capable of detecting a reception error occurrence status when receiving data, to set a distribution conformance level. Determining means for determining, and distribution control means for distributing the distribution data according to the distribution conformance level determined by the determining means to the terminal device side via the broadcasting means. Host device. 8. The host according to claim 7, wherein said distribution control means is configured to distribute predetermined reception error detection data to a terminal device prior to distribution of said distribution data. apparatus. 9. The delivery control means is assumed to execute delivery based on a predetermined delivery schedule.
8. The system according to claim 7, wherein the distribution schedule is changed based on the determined distribution conformance level, and the distribution data is distributed to the terminal device based on the changed distribution schedule. Or the host device according to 8.