JPH10257001A - Information transmission method and system therefor, and host device used for the system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the information transmission method that properly realizes countermeasures against the occurrence of a reception error in a terminal equipment regardless of an advantage of simultaneous transmission of information in a broadcast form from a host device to a plurality of terminal equipments. SOLUTION: In the case of transmission of data from a host device 2 to a terminal equipment 1, since the data are transmitted while being multiplexed on a satellite broadcast wave through a satellite channel, an advantage of simultaneous transmission of large capacity data in a broadcast form is obtained at first. Then on the occurrence of a reception error in a terminal equipment 1, the error is countermeasured as follows; each terminal equipment 1 detects an error for each information in the unit of frames and up-loads the reception result denoting the presence of the error to the host device 2 for each information, and the host device 2 sends the information with many error detection numbers to the terminal equipment 1 again based on the reception result up- loaded from each terminal equipment 1.

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 transmitting information from a host device to a terminal device, and a host device effective for use in the system.

[0002]

2. Description of the Related Art
In an information distribution system in which service providing information necessary for providing a service executed in a terminal device is distributed from a host device, a communication line capable of bidirectional information transmission between the host device and the terminal device such as a telephone line. And information was transmitted from both sides via this communication line. The above-described service providing information is distributed (downloaded) from the host device, and predetermined information such as operation information is uploaded from the terminal device to the host device.

However, in an information distribution system in which new service providing information is distributed at relatively short intervals, the time required for information distribution becomes longer as the number of terminal devices belonging to the system 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 it is necessary to distribute information of a new song 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 information transmission in a broadcast format using a communication / broadcasting satellite, etc., which has a large communication capacity and can simultaneously transmit information to a plurality of receiving apparatuses. Is preferred. That is,
When information transmission in such a broadcast format is adopted, there is a disadvantage due to the characteristic of simultaneous transmission to an unspecified large number of people in a "broadcast". 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 that data cannot be received as a satellite communication terminal from the beginning, 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, when an information reception error occurs in a certain terminal device, if retransmission is performed only for that terminal device,
Thereafter, if there is an error in receiving the same information, the same information must be retransmitted again. In other words, when transmitting information in a broadcast format to a plurality of terminal devices, it is efficient because information can be transmitted to a large number of terminal devices at one time at the first transmission, but it is efficient when there is a reception error. However, if information is transmitted in a broadcast format that can be simultaneously transmitted to an unspecified number of people only due to the situation of one terminal device, there is an inefficient aspect.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and has an advantage of transmitting information in a broadcast format from a host device to a plurality of terminal devices at the same time. It is an object of the present invention to provide an information transmission method for appropriately realizing the countermeasure in the case where the information is transmitted, a system for realizing the transmission method, and a host device used in the system.

[0008]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, an information transmission method according to the present invention is characterized in that a host device and a plurality of terminal devices are connected to a host device. In the information transmission system connected from the device to the terminal device side via broadcast means capable of simultaneously transmitting an unspecified number to a large number, and connected via at least the communication device capable of uploading from the terminal device to the host device, A method for transmitting predetermined transmission information from a host device to a terminal device, wherein the transmission information includes a plurality of predetermined partial information, and the transmission information includes the plurality of partial information. Is transmitted from the host device to the terminal device via the broadcasting means, and each terminal device that has received the transmitted transmission information detects an error in units of partial information, and detects the error. Upload the reception result with which the partial information can be specified to the host device via the communication means, request to transmit the error-detected partial information again, and in the host device which received the retransmission request, upload from each terminal device. Based on the received result, partial information having a large number of detected errors is prioritized and transmitted to the terminal device again via the broadcasting means.

According to the information transmission method, the host device transmits the transmission information composed of a plurality of predetermined pieces of partial information to the terminal device via the broadcast means capable of transmitting an unspecified number of simultaneous information to the terminal device. . Each terminal device that has received the transmitted information for transmission detects an error in units of partial information, and uploads a reception result specifying the detected partial information to the host device via the communication unit. Then, a request is made to retransmit the partial information for which the error has been detected. The host device receiving the retransmission request from the terminal device,
Based on the reception result uploaded from each terminal device,
The partial information having a large number of detected errors is prioritized and transmitted to the terminal device again via the broadcasting means.

As described above, when transmitting the transmission information from the host device to the terminal device, the transmission via the broadcasting means is used first, so that the transmission information is individually transmitted to all the terminal devices. An advantage of simultaneous transmission of large-capacity information in a broadcast format can be obtained as compared with the case of transmitting information. Therefore, it is very effective especially when one host device needs to transmit transmission information to many terminal devices.

However, in the case of information transmission in a 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. In this case, it is necessary to upload the reception result from the terminal device and transmit the transmission information having the reception error again. In this case, the information transmission method of the present invention is as follows. Adopt a characteristic method.

That is, as described above, each terminal device detects an error in units of partial information, uploads a reception result specifying the partial information to the host device, and transmits the partial information for which the error was detected. The host device requesting retransmission and receiving the retransmission request from the terminal device, based on the reception result uploaded from each terminal device, gives priority to partial information with a large number of error detections, via the broadcasting means It is transmitted to the terminal device again. Therefore, for example, when the transmission information is composed of 100 pieces of partial information and transmitted to 100 terminal devices, reception results from the 100 terminal devices are totaled to constitute the transmitted transmission information. The 100 pieces of partial information are arranged in the order of the number of detected errors, and retransmission is performed with priority given to the number of detected errors. It is desirable for the terminal device to receive all the transmission information earlier, but this can be realized by prioritizing and retransmitting the information with the highest number of error detections as described above.

That is, the information transmission method has an advantage of transmitting information in a broadcast format from a host device to a plurality of terminal devices at the same time, and can appropriately cope with a reception error in a terminal device. You can. Note that the timing for retransmission is 100 when transmitting to 100 terminal devices as in the above example.
It is conceivable to receive all the reception results from the terminal devices and retransmit them based on the result of totalizing them. That is, retransmission is performed after receiving the reception results from all the terminal devices belonging to the information transmission system. Of course, 10
Retransmission processing is performed once when reception results from a predetermined number or more terminal devices, such as 50 devices, are obtained instead of all 0 devices, and then retransmission processing is performed after obtaining reception results from the remaining terminal devices. You may. However, in this case,
Since retransmission of the same partial information may be performed repeatedly, if time conditions permit, it is preferable to retransmit after obtaining reception results from all terminal devices as described above. I can say.

The transmission information and the partial information will be described. The transmission information is composed of a plurality of predetermined pieces of partial information. For example, in a communication karaoke system, the transmission information is one or a plurality of pieces of karaoke music information. When a plurality of pieces of karaoke music information are collectively referred to as "transmission information", each piece of music may be "partial information", or one piece of music is further divided into a plurality of frame data. May be used as “partial information”.
If the data length of one piece of partial information is too long, the burden on retransmission will increase. Conversely, if the data length of one piece of partial information is too short, the processing load of data division on the host device side or data reconstruction on the terminal device side increases. Therefore, the setting method of the partial information may be appropriately devised depending on the content of the transmission information and various circumstances in the transmission system.

As a system for realizing the above-described information transmission method, for example, the configuration shown in claim 2 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. An information transmission system connected to the host device for transmitting predetermined transmission information from the host device to the terminal device, wherein the host device is configured to transmit the transmission information by a plurality of predetermined pieces of partial information. A first information transmitting unit configured to transmit information for transmission including a plurality of pieces of partial information to a terminal device via a broadcasting unit;
The terminal device includes a receiving unit that receives transmission information transmitted from the host device via the broadcasting unit, and partial information from the transmission information received by the receiving unit. Error detection means for detecting an error in units, reception result creation means for creating a reception result capable of specifying partial information in which an error has been detected by the error detection means, and reception creation means for the reception result creation means Retransmission request means for uploading the result to the host device via the communication means and requesting transmission of the error-detected partial information again, further comprising: a reception result storage means for storing the reception result When a retransmission request is received from a terminal device, the number of error detections is determined based on the reception result uploaded from each of the terminal devices and stored in the reception result storage means. More partial information with priority, the information transmission system characterized in that it comprises a second transmission control means for transmitting again to the terminal apparatus via the broadcast means.

In this information transmission system, the host device configures transmission information as a plurality of predetermined pieces of partial information, and transmits the transmission information to the terminal device via the broadcasting means by the first transmission control means. The terminal device receives the transmission information transmitted from the host device via the broadcasting means, and detects an error in units of partial information from the received transmission information. Then, the reception result creating unit creates a reception result that can specify the partial information where the error is detected, uploads the reception result to the host device via the communication unit by a retransmission request, and deletes the partial information where the error is detected. Request to send again.

The host device that has received the retransmission request from the terminal device stores the reception result in the reception result storage means, and performs the following processing by the second transmission control means. That is, based on the reception result stored in the reception result storage means, partial information with a large number of detected errors is prioritized and transmitted to the terminal device again via the broadcasting means.

The effect of this information transmission system is the same as that described in the above-mentioned information transmission method, and therefore will not be described here. However, a supplementary explanation will be given on the reception result created by the reception result creation means of the terminal device. Keep it. This reception result is uploaded to the host device, and considering the purpose that the host device determines the number of error detections in units of partial information based on the reception result, at least identification information of the partial information having the reception error, etc. Is sufficient if it is included. However, if it is also desired to confirm that the reception has been performed correctly, it is necessary to create a reception result for all partial information constituting the transmission information so as to determine whether or not a reception error has occurred.

Further, in the present invention, "retransmission is preferentially performed with a large number of detected errors", but since this retransmission is also performed via the broadcasting means, there is no need to specify the terminal device of the transmission destination. . Therefore, when uploading from the terminal device to the host device, the identification information of the transmission source terminal device may be omitted. However, in consideration of management as an information transmission system, there is a case where it is desired to obtain data such as which terminal device has a large number of reception errors. Therefore, identification information of the terminal device may be included.

In the host apparatus, it is fundamental to "retransmit a message with a large number of detected errors with priority". For example, there may be a plurality of pieces of partial information having the same number of detected errors. In this case, the processing may be appropriately performed in accordance with, for example, the order in which the total data is created. However, as described in claim 3, a priority relationship between a plurality of pieces of partial information constituting the transmission information is stored, and an error is stored. When there are a plurality of pieces of partial information having the same number, the pieces of partial information may be transmitted in an order based on a priority relationship between the pieces of partial information.

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 a broadcasting form using satellite communication is effective because it has a large communication capacity and can simultaneously transmit a large amount of information to a plurality of receiving devices. .

[0022] The communication means may be a means for transmitting information 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, for example, the information is transmitted from the host device to the terminal device side. It is preferable that both the broadcasting means used and the communication means for transmitting information in a broadcasting format used for transmitting information from the terminal device to the host device use satellite communication via the same satellite.

This is because, in the case of the broadcasting format, the burden tends to be generally large in terms of equipment or cost. That is, in the case of information transmission from the host device to the terminal device via the broadcasting device, for example, a transmission parabolic antenna or the like is used as the first transmitting device on the host device side, and the first receiving device of each terminal device is used as the first transmitting device. As a result, a parabolic antenna for reception or the like is required, and there is a possibility that the cost becomes large including the fee for using the satellite. 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 according to claim 6 is connected to the terminal device side via broadcast means capable of simultaneously transmitting an unspecified number of devices,
A host device connected via at least communication means capable of uploading from the terminal device and capable of transmitting predetermined transmission information to the terminal device, wherein the transmission information is configured by predetermined plural pieces of partial information. Transmission information configuration means to perform,
First transmission control means for transmitting transmission information composed of a plurality of pieces of partial information to the terminal device via the broadcasting means, and reception result storage means for storing a reception result uploaded from the terminal device; When a retransmission request is received from the terminal device to retransmit the partial information for which the error has been detected by the terminal device, the terminal device is uploaded from each terminal device,
A second transmission control unit for giving priority to partial information having a large number of detected errors based on the reception result stored in the reception result storage unit and transmitting the partial information to the terminal device again via the broadcasting unit. Features.

Regarding the operation and effect of this host device,
The information transmission method and the system have been described in the description above, and thus will not be repeated here. Of course, in realizing the information transmission system of the present invention, the present invention is not limited to this host device, but a device using a device different from the above device as long as its purpose, operation, and effect are common. Needless to say, it also includes

[0027]

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 an information transmission system as one embodiment of the present invention. This information transmission system is composed of one host device 2 as a “host device” and a plurality of terminal devices 1 as a “terminal device”. Two types of information transmission of “broadcasting means” via the satellite 30 are possible. And
When the information is transmitted via the public line 50, the host device 2 can specify the terminal device 1 and transmit information. For example, if the public line 50 is a telephone line, a connection to a desired terminal device 1 can be realized by designating a telephone number of the terminal device 1 from the host device 2 and making a call. On the other hand, when passing through the satellite 30, information 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 that is connected to a parabolic antenna 110 that receives satellite broadcast waves broadcast from the host device 2 via the satellite 30 and separates multiplexed information from the satellite broadcast waves. And a demodulator 14 for demodulating information. Note that the information 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 data is image data compressed based on the PEG2 video encoding method, the terminal device 1 of the present embodiment
Is provided with a remote control light-receiving unit 18 for receiving a request from a remote control 112 from a user and a decoder 17 for decoding MPEG2 data stored in the HDD 16. The image data decoded by the decoder 17 is transmitted to a CRT 11 as a display unit.
1 can be displayed and output.

The parabolic antenna 110, tuner 15, and demodulator 14 correspond to "first receiving means".
The information demodulated by the demodulator 14 is transmitted to the CPU 1
The data is stored in the HDD 16 via the “0”. At this time, an error is detected. In the present embodiment, information is received in units of frames, and error detection is performed in units of frames. Therefore, the information in frame units corresponds to “partial information”. As a method of detecting an error, for example, a check sum method is used. If an error is detected in the error detection, a request is made to create a reception result that enables the frame in which the error is detected to be specified, and to retransmit information corresponding to the frame. Therefore, the CPU 10 corresponds to “error detection means”, “reception result creation means”, and “retransmission request 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 information to be transmitted with respect to CPU 20, and CPU 20 as control means for executing control of the entire apparatus including a process of dividing information to be transmitted into partial information, that is, a frame unit. , Its CPU2
ROM 21 storing a program to be executed by C.O.
A RAM 22 as a temporary storage means, a transmission control device 24 for controlling transmission of information divided in frame units via a satellite line, and a modulator 25 for modulating the information and multiplexing the information into a satellite broadcast wave. Have. Then, the satellite broadcast wave modulated by the modulator 25 is transmitted to the satellite 30 by the parabolic antenna 210.

The CPU 20 corresponds to "transmission information forming means", and the RAM 22 corresponds to "reception result storage means". Further, in addition to the CPU 20, the transmission control device 24,
The modulator 25 and the parabolic antenna 210 correspond to “first transmission control means” and “second transmission control means”.

Next, the structure of information transmitted from the host device 2 to the terminal device 1 will be described with reference to FIG. In the present embodiment, the information to be transmitted is divided into frame units as described above, and one frame is composed of an offset address of the first data, a serial number of the frame, and stored data as shown in FIG. , The name of the stored data, the data itself to be distributed, and the checksum.

This information transmission system transmits data to the terminal device 1 through a satellite line, which has the advantage of simultaneous transmission of large amounts of data in a broadcast format. For information in which a reception error has occurred, the reception error has occurred. The reception result specifying the information in units of frames is uploaded from each terminal device 1 to the host device 2, and only the information of the corresponding frame is retransmitted. However, the retransmission is performed with priority given to the information of the frame having a large number of reception errors. This allows
An object of the present invention is to appropriately cope with a reception error in a terminal device while having an advantage of simultaneous transmission of a large amount of information in a broadcast format.

An information transmission process in the information transmission system will be described with reference to the drawings. First, the information transmission control processing in the host device 2 will be described with reference to the flowchart in FIG. In the first step S11, information to be distributed to the terminal device 1 is read from the HDD 26 and divided into frame units. One divided frame has a structure shown in FIG.

Then, in S12, the transmission information for each frame divided in S11 is transmitted through a satellite line. When transmitting information via a satellite line, the information is transferred to a modulator 25 via a transmission control device 24, and the modulator 25 modulates the information and multiplexes the information into a satellite broadcast wave. Then, the satellite broadcast wave modulated by the modulator 25 is transmitted to the satellite 30 by the parabolic antenna 210 and the terminal device 1
Is transmitted in the form of a broadcast.

Then, in subsequent S13, it is determined whether or not information indicating the reception result has been received from the terminal device 1. This reception result indicates whether the data has been correctly received or a reception error has occurred for each frame of data. Then, when the reception result for each terminal device 1 is received (S13: YES), the reception result is stored in RA in S14.
The process proceeds to S15 after being stored in M22, and if not received (S13: NO), the process directly proceeds to S15.

In S15, it is determined whether or not a predetermined time has elapsed. If the predetermined time has not yet elapsed (S15:
NO), and return to S13. On the other hand, if the predetermined time has elapsed (S15: YES), the process proceeds to S16. The predetermined time is a time sufficient for all the terminal devices 1 that are to upload the reception result to transmit the reception result, and for the host device 2 to receive all of the reception result.

As described above, when the reception results are obtained from all the terminal devices 1 that are to upload the reception results, a reception result table as shown in FIG. 9 is created. For example, if there are data a to z, information indicating whether reception is normal or error for each of the terminal devices 1 (in this case, normal reception is indicated by “○” and reception An error is indicated by “x”). As shown in FIG. 9, the number of reception errors is also stored in data units.

In S16, the reception results created as the reception result table are totaled to create a retransmission table as shown in FIG. This retransmission table arranges data in the order of the number of reception errors described above. In the example shown in FIG. 9, 142 data b and data c
It is assumed that there is a reception error of 32 pieces of data and 7 pieces of data x, and the reception is normally performed in other cases. Therefore, in this case, in the retransmission table shown in FIG. 10, the order of retransmission is data b first, data c next, data x third, and no corresponding data after the fourth. The target is only the above three.

In the following S17, it is determined whether or not there is data to be retransmitted. If there is data to be retransmitted (S17: YES), the process proceeds to S18 and retransmits data in the order of the retransmission table shown in FIG. 10, that is, in this case, data b → data c → data x. I do. Then, after retransmission, the process returns to S13. On the other hand, if there is no data to be retransmitted (S17: NO), the transmission control routine ends as it is.

After retransmitting in S18, the process returns to S13,
The process of S13 and thereafter is repeated because a reception error may occur in the terminal device 1 with respect to the retransmitted data, so that the determination is made based on the reception result and, if necessary, the retransmission is performed again. It is. Therefore,
The predetermined time for determining whether or not the time has elapsed in S15 is a relatively long time because, for example, in the first transmission, it is necessary to wait for reception results from all the terminal devices 1 belonging to the system. When the number of transmitted data is only three as in the example of FIG. 10 described above, for example,
At the time of the second transmission, the predetermined time required for the determination in S15 may be a relatively short time.

According to the transmission control routine, the retransmission processing is repeated until the reception result including the information indicating the reception error is not received. Could be stopped. Since the retransmission is a transmission process in a “broadcast” format via a satellite line, for example, if retransmission of one data to one terminal device 1 is repeated many times, the entire system is inefficient. This is because Therefore, if there is a terminal device 1 which cannot stop retransmission at a predetermined number of times and can still obtain normal data at that time, another method, for example, special transmission via a terrestrial line via the public line 50 may be performed. Conceivable.

Next, the information receiving process in the terminal device 1 will be described with reference to the flowcharts of FIGS. In the first step S21, information in a frame unit transmitted from the host device 2 via a satellite line is received. A satellite broadcast wave in which information is multiplexed is transmitted from the satellite 30. Since this is a broadcast wave, it is transmitted simultaneously to an unspecified number of terminal devices 1. 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.

In the subsequent S22, it is determined whether or not there is a reception error with respect to the received and demodulated frame unit information. If there is no reception error (S22: NO), S
23, and transfers the received frame unit information to the HDD.
16 and the reception result is determined to be "normal" in S24.
In the reception result table in the RAM 12. On the other hand, if there is a reception error (S22: YES), the flow shifts to S25, where the reception result is stored in the reception result table as "error". This reception result table corresponds to data for one terminal in the reception result table on the host device 2 side shown in FIG.

After storing the reception result as "normal" or "error" in S24 or S25, the process shifts to S26 to determine whether all the information transmitted from the host device 2 has been received. If the information has not been received yet (S26: NO), the process returns to S21 and repeats the receiving process.
6: YES), proceeds to S27, and uploads the reception result created in the reception result table of the RAM 12 to the host device 27.

When the upload processing of the reception result in S27 is completed, the process proceeds to S28, and it is determined whether or not the reception result table of the RAM 12 has a reception result of “error”. If there is no "error" reception result (S28: N
O) Since there is no need to receive retransmission, the reception control routine as the terminal device 1 ends here.

On the other hand, if there is a reception result of "error" in the reception result table (S28: YES), it is necessary to receive retransmission of the data in which the error has occurred.
Move to 29. If the own terminal device 1 has received an "error" reception result, the reception result has been uploaded to the host device 2 in S27. The transmission is made. Therefore, in S29, the retransmitted information is received in frame units.

Then, in S30, it is determined whether or not the received information is stored as "error" in the reception result table created in the previous reception processing.
If it is stored as "error" (S30: Y
ES), and proceeds to S31. In S31 to S34, the same processing as in S22 to S25 described above is performed. That is,
It is determined whether there is a reception error with respect to the information in the frame unit (S31), and if there is no reception error (S3).
1: NO), the process proceeds to S32, the received frame unit information is stored in the HDD 16, and the received result is set to "normal" in S33 and stored in the received result table in the RAM 12. On the other hand, if there is a reception error (S31: YE
S), the process proceeds to S34, and the reception result is stored in the reception result table as “error”.

If a negative determination is made in S30, that is, if the result is stored as "normal" in the reception result table, the flow shifts to S33, and the reception result is stored in the reception result table as "normal". As described above, the series of processing from S31 to S34 is executed only for the information stored as "error" in the reception result table in S30 because the information normally received in the previous reception processing is used. Even in this case, an error may occur in the current reception processing. However, in this case, since normal information already exists, there is no need to receive retransmission from the host device 2.
Therefore, the determination process in S30 is performed in order to select only the information that really needs retransmission.

After storing the reception result as "normal" or "error" in S33 or S34, the process shifts to S35 to determine whether all the information transmitted from the host device 2 has been received. In the specific examples shown in FIGS. 9 and 10 used in the description of the transmission processing in the host device 2, there are three data b, c, and x to be retransmitted. It is determined whether or not all have been received.

If the reception of the information has not been completed (S35: NO), the process returns to S29 and repeats the reception process again. However, if the reception has been completed (S35: Y).
ES), the process proceeds to S36, and the reception result created in the reception result table of the RAM 12 is uploaded to the host device 27. Thereafter, the process returns to S28, and it is again determined whether or not the reception result table of the RAM 12 has a reception result of "error". Here, if there is no reception result of “error” (S28: NO), there is no need to receive retransmission.
The present reception control routine ends here.

According to this reception control routine, the re-reception processing after S29 is repeated as long as the reception result indicating the error does not disappear in the reception result table. Could be stopped. That is, as described in the transmission control routine described above, the retransmission from the host device 2 is a transmission process in a “broadcast” format via a satellite line. This is because if retransmission is repeated many times, the entire system becomes inefficient.

The transmission control process from the host device 2 and the reception process at the terminal device 1 have been described above. FIG. 8 shows a flow of data related to such information transmission as a sequence diagram. FIG. 8 also describes the second and subsequent data transmissions. However, if a reception result indicating that all information has been normally received from all the terminal devices 1 has been uploaded, the second and subsequent data transmissions will be described. There is no.

As described above, in the information transmission system according to the present embodiment, when data is transmitted from the host device 2 to the terminal device 1, the data is first multiplexed with a satellite broadcast wave via a satellite line and transmitted. 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 transmit data to many terminal devices 1. However, in the case of information transmission in a 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”. An error may occur. In that case, it is necessary to have the terminal device 1 upload the reception result and transmit the information having the reception error again. In this case, the following characteristic method is adopted.

That is, each terminal device 1 detects an error for each frame of information, and uploads a reception result indicating the presence or absence of an error to the host device 2 for each information. In the host device 2, based on the reception result uploaded from each terminal device 1, information with a large number of detected errors is preferentially transmitted to the terminal device 1 again. It is desirable that the terminal device 1 receives all information earlier, but this can be realized by prioritizing and retransmitting the information with the highest number of detected errors as described above.

In the specific example shown in FIG. 9, the number of reception errors is 142 for data b, 32 for data c, and 7 for data x. By doing so, for example, terminal A or the like in which only data b has an error, completes reception of all information at that time. As described above, the terminal device 1 that completes the reception of all the information when only the data b is received is relatively many. On the contrary, when the data x is retransmitted, all the information is received when the retransmission is completed. It is conceivable that the number of the terminal devices 1 for which the reception of the terminal is completed is relatively small, and there is no terminal device 1 at all. Therefore, this information transmission process is very effective in that the number of terminal devices 1 that have completed normal reception of all information increases more quickly.

As described above, the present invention is not at all limited to such embodiments, and can be implemented in various forms without departing from the gist of the present invention. For example, as for the timing of retransmission, in the above-described embodiment, all the reception results from all the terminal devices 1 that plan to upload the reception result are received, and retransmission is performed based on the result of summing them. For example, if there are a total of 100 devices, if a reception result from about 50 terminal devices 2 is obtained, a retransmission process is performed once at that time, and then a reception result from the remaining terminal devices 1 is obtained and a retransmission process is performed. May be performed. However, in this case, there is a possibility that the same information may be duplicated and retransmitted. Therefore, if time conditions and the like allow, the reception results from all the terminal devices 1 are transmitted as described in the above embodiment. It can be said that it is preferable to retransmit after obtaining.

In the above embodiment, the information is handled in units of frames. However, how to configure the information corresponding to this one frame may be changed as appropriate according to the system operation or the like. For example, in the case of a communication karaoke system, information transmitted from the host device 2 to the terminal device 1 is one or a plurality of pieces of karaoke song information.
When it is desired to transmit a plurality of pieces of karaoke song information, each song may be assigned as frame information, or one song may be divided into a plurality of pieces of frame information. If the data length of one piece of partial information is too long, the burden on retransmission will increase. Conversely, if the data length of one piece of partial information is too short, the processing load of data division on the host device 2 side or data reconstruction on the terminal device 1 side increases. Therefore, the setting method of the partial information may be appropriately devised depending on the content of the transmission information and various circumstances in the transmission system.

In the above embodiment, if an error is detected in the information received by the terminal device 1, it is not mentioned whether or not to store the information. Predetermined pseudo information may be input to the detected frame and stored.
With this configuration, when the information corresponding to the frame in which the error is detected is transmitted from the host device 2 again,
If the retransmitted information is overwritten on the corresponding frame in which the pseudo information is input, the information of the received frame can be appropriately overwritten on the place where it should be.

In the above embodiment, the satellite 30
Data transmission by satellite line using
The same effect can be obtained even in the case of data transmission in a broadcast format using terrestrial waves without using the satellite 30. Further, in the above embodiment, the upload of the reception result from each terminal device 1 to the host device 2 is performed via the ground line via the public line 50 as shown in FIG. Another embodiment that is performed via a line is also conceivable. In this case, as shown in FIG. 11, since the host device 202 and the terminal device 101 perform bidirectional data communication via the satellite 30, the parabolic antenna 1210 on the host device 102 side and the terminal device 10
The parabolic antenna 1110 on one side needs to be configured to be capable of transmitting and receiving data.
02 and the terminal device 101 also need to have a configuration for executing transmission / reception control including modulation and demodulation in accordance therewith. However, the modem 1 of the terminal device 1 required in the above embodiment
3 (see FIG. 2) and the modem 23 (see FIG. 3) of the host device 2 become unnecessary.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an information transmission 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 of a data structure of information in a frame unit transmitted from the host device to the terminal device according to the embodiment;

FIG. 5 is a flowchart illustrating an operation related to transmission control executed in the host device of the embodiment.

FIG. 6 is a part of a flowchart illustrating an operation related to reception control executed in the terminal device of the embodiment.

FIG. 7 is a part of a flowchart illustrating an operation related to reception control 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.

FIG. 9 is an explanatory diagram of a reception result table created in the host device of the embodiment.

FIG. 10 is an explanatory diagram of a retransmission table created in the host device of the embodiment.

FIG. 11 is a block diagram illustrating a schematic configuration of an information transmission system according to another 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

Claims (6)

[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. A method for transmitting predetermined transmission information from the host device to a terminal device in an information transmission system connected via an uploadable communication unit, wherein the transmission information includes a plurality of predetermined pieces of partial information. The transmission information composed of the plurality of pieces of partial information is transmitted from the host device to the terminal device via the broadcasting unit, and the transmitted transmission information is received. Each terminal device detects an error in units of the partial information, and uploads a reception result capable of specifying the detected partial information to the host device via the communication unit. Loading, requesting that the error-detected partial information be transmitted again, and receiving the retransmission request, the host device, based on the reception result uploaded from each of the terminal devices, reads the partial information with a large number of detected errors. An information transmission method, wherein priority is given to transmission to the terminal device again via the broadcasting means. 2. A host device and a terminal device are connected to the terminal device side from the host device via a broadcasting means capable of transmitting an unspecified number of devices simultaneously, and at least uploading from the terminal device to the host device is possible. And an information transmission system for transmitting predetermined transmission information from the host device to the terminal device, wherein the host device transmits the transmission information to a plurality of predetermined A transmission information configuring unit configured by partial information; and a first transmission control unit configured to transmit the transmission information configured by the plurality of partial information to the terminal device via the broadcasting unit. On the other hand, the terminal device comprises: a receiving unit for receiving transmission information transmitted from the host device via the broadcasting unit; and Error detection means for detecting an error in units of partial information, reception result creation means for creating a reception result capable of specifying the partial information in which the error has been detected by the error detection means, creation by the reception result creation means Uploading the received result to the host device via the communication means, and retransmission requesting means for requesting that the error-detected partial information be transmitted again.The host device further comprises: A reception result storage unit for storing, when a retransmission request is received from the terminal device, the number of error detections based on the reception result uploaded from each of the terminal devices and stored in the reception result storage unit. An information transmission system characterized by comprising second transmission control means for prioritizing partial information having a large number and transmitting the partial information again to the terminal device via the broadcasting means. . 3. The information transmission system according to claim 2, wherein said host device stores a priority relationship between a plurality of pieces of partial information constituting said transmission information, and said second transmission control means controls said second transmission control means. When retransmitting partial information, if there is a plurality of partial information having the same number of errors, the information transmission system is configured to transmit the partial information in an order based on a priority relationship between the partial information. 4. The information transmission system according to claim 2, wherein the communication means capable of uploading from the terminal device to the host device transmits information in a broadcast format that allows simultaneous transmission to an unspecified number of people. An information transmission system characterized by the above. 5. The information transmission system according to claim 4, wherein: a broadcast unit used for transmitting information from the host device to the terminal device; and an unspecified majority used for transmitting information from the terminal device to the host device. An information transmission system characterized in that communication means for transmitting information in a broadcast format that can be transmitted simultaneously uses satellite communication via the same satellite. 6. The terminal device is connected to the terminal device via broadcast means capable of simultaneously transmitting an unspecified number of devices, and at least via communication means capable of uploading from the terminal device. A transmission device configured to transmit predetermined transmission information to the transmission device, wherein the transmission information includes a plurality of predetermined pieces of partial information; First transmission control means for transmitting information to the terminal device via the broadcasting means, reception result storage means for storing a reception result uploaded from the terminal device, and error detection in the terminal device If a retransmission request is received from the terminal device to transmit the partial information again,
Based on the reception result uploaded from each of the terminal devices and stored in the reception result storage unit, preferentially giving partial information with a large number of detected errors, and transmitting the partial information to the terminal device side again via the broadcasting unit. A host device comprising transmission control means.