JP2003234739A - Digital data transmitting/receiving system and digital data transmitting/receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a receiving terminal to receive right digital data regardless of a communication environment only by once transmitting the digital data from a transmitter. <P>SOLUTION: A transmission server 1 performs digital broadcasting over a wide band through a digital communication network 3 to each of receiving terminals 2a, 2b...2n. The receiving terminals 2a, 2b...2n each confirm whether the digital data can be rightly received or not from error detection information added to the digital data received from the transmission server 1. For example, a communication means in the receiving terminal 2a communicates with communication means in the transmission server 1 and the other receiving terminals 2b...2n and reports a communication status of the receiving terminal 2a itself. When the receiving terminal 2a confirms that there is an omission in the received digital data, the omitted digital data are complemented from the receiving terminal 2b of the predetermined high priority. By mutually complementing the digital data among the indidual receiving terminals 2b...2n, the reception is not affected by external factors. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital data transmission / reception system for transmitting / receiving digital data by multicast or broadcast such as digital broadcasting, and more particularly, it receives a data broadcast program broadcast by multicast or broadcast. The present invention relates to a digital data transmission / reception system that improves a data reception error when performing.

[0002]

2. Description of the Related Art Generally, in a data broadcasting program transmitted by multicast broadcasting to a specific user or broadcasting broadcasting to an unspecified user, a program having the same content is repeatedly broadcast, or While appropriately changing the program content, the same content is repeatedly broadcast a plurality of times over time. On the other hand, on the receiving device side, the reception data is updated every time the program content is changed, even when the reception condition of the radio wave is poor. Therefore, when the receiving device receives data when the radio wave condition is poor, part of the received data may be lost. Therefore, various techniques for preventing such loss of received data have been reported. For example, JP-A-11-136
Japanese Patent No. 648 discloses a technique for improving a data reception error of a receiving device that receives a data broadcast program. According to this technology, instead of updating all of the received data files every time a data broadcast program is repeatedly broadcast, the already correctly received data is used as it is and cannot be received. The file group of the received data is reconstructed by complementing only the missing data. This makes it possible to easily and accurately correct the error in the received data, and reduce the error in the program information used on the receiving device side.

[0003]

However, in the conventional technique as described above, since the same digital data is repeatedly transmitted from the transmitter, the receiver corrects the error due to the reception failure of the digital data. It can be carried out. That is, if the transmitting device transmits the digital data only once, the receiving device cannot complement the error in the missing portion of the data. Therefore, in the conventional digital data transmission / reception system, the transmission device must repeatedly transmit the digital data in order to correct the error in the digital data, resulting in an increase in the transmission cost. Furthermore, even in broadcasting in which data transmission is repeated a plurality of times, correct reception data cannot be complemented when the receiving device again fails to receive the same portion of data and data loss occurs.

Further, unlike a transmitting device which performs wireless communication such as satellite broadcasting, when digital data is transmitted from a transmitting device having a communication means capable of reliable communication such as wired communication, the receiving device is digital. When the data reception fails, the processing for acquiring the correct packet concentrates on the communication means, which may cause congestion of the communication means. If the number of communication lines is increased in order to avoid such congestion of the communication means, the facility cost and maintenance cost of the communication means increase and the communication cost may increase.

The present invention has been made in view of the above circumstances, and an object thereof is to simply transmit digital data once from a transmitter without increasing the number of communication lines. The present invention provides a digital data transmission / reception system that enables a receiving terminal to receive correct digital data regardless of the communication environment.

[0006]

In order to achieve the above object, a digital data transmission / reception system of the present invention comprises one transmission server and a plurality of reception terminals, and transmits digital data from the transmission server to a plurality of reception terminals. In a digital data transmission / reception system for distribution, among a plurality of receiving terminals,
The receiving terminal that has missing data in at least part of the received digital data selects one of the receiving terminals that normally received all the digital data, and extracts the missing data from the digital data of the selected receiving terminal. It is characterized in that it is configured to acquire digital data for complementation and complement the received digital data.

Further, in the digital data transmission / reception system of the present invention, the transmission server adds the error detection information for determining whether or not the digital data is normally received to the digital data to be transmitted, and transmits the digital data. Each of the receiving terminals is to check the presence or absence of missing data based on the error detection information added to the received digital data.

Further, the digital data transmitting / receiving system of the present invention comprises one transmitting server and a plurality of receiving terminals,
In a digital data transmission / reception system that distributes digital data from a transmission server to a plurality of receiving terminals, the transmission server converts the digital data to be transmitted into a plurality of packets to which header information for identifying the digital data is added. The data / packet converting means and the packet transmitting means for sequentially transmitting the plurality of packets to the plurality of receiving terminals are provided.
Packet receiving means for sequentially receiving the packets transmitted from the transmitting server, packet / digital data converting means for converting the received packets into digital data, digital data storage means for storing the digital data that was normally received, and normal At least a part of the received digital data, which is provided with reception information storage means for storing the digital data that could not be received by the receiver and its header information, and communication means for communicating with other receiving terminals and the transmission server that received the digital data. The receiving terminal having the missing data in the, using the communication means, the information of the digital data stored in the reception information storage means and its header information, to the receiving terminal that normally received all the digital data, the Obtain normal digital data from the receiving terminal and store it in the digital data storage means. And wherein the updating of the digital data being 憶.

Further, in the digital data transmission / reception system of the present invention, the communication means selects the receiving terminal that has received the digital data having the missing data and the receiving terminal that has normally received all the digital data in order of good communication conditions. The feature is that they are physically connected.

In addition, the digital data transmission / reception system of the present invention monitors the reception status of at least two or more reception terminals among a plurality of reception terminals, and any two of them are monitored.
Whether or not all the receiving terminals monitored by the receiving terminal monitoring means are able to receive the digital data normally through the communication means, provided with the receiving terminal monitoring means for storing the communication cost when one receiving terminal communicates. When receiving the notification to the receiving terminal monitoring means, the receiving terminal monitoring means receives the digital data normally from the receiving terminal that receives the digital data to the receiving terminal that cannot receive the digital data normally. It is characterized in that a device is selected and notified.

Further, according to the present invention, there is provided a digital data transmitting / receiving method comprising one transmitting server and a plurality of receiving terminals, wherein digital data is distributed from the transmitting server to the plurality of receiving terminals. The receiving terminal having missing data in at least a part of the digital data selects one receiving terminal from the receiving terminals that have normally received all the digital data, and complements the missing data from the digital data of the selected receiving terminal. It is characterized in that it acquires digital data for the purpose and complements the received digital data.

Further, in the digital data transmission / reception method of the present invention, the transmission server responds to the digital data transmitted by
Whether or not there is missing data based on the error detection information added to the received digital data by each of the plurality of receiving terminals, and the error detection information for determining whether or not the digital data is normally received is transmitted. It is characterized by confirming.

Further, according to the present invention, in a digital data transmitting / receiving method comprising one transmitting server and a plurality of receiving terminals, wherein the transmitting server distributes the digital data to the plurality of receiving terminals, the transmitting server transmits the digital data. A step of converting the plurality of packets with header information for identifying the digital data, and a plurality of packets sequentially, to a plurality of receiving terminals, a plurality of receiving terminals, respectively, A step of sequentially receiving the packets transmitted from the transmission server, a step of determining whether there is a packet that could not be normally received, a step of converting the normally received packet into digital data and storing the digital data, The step of storing the packet and header information that could not be received normally and the step that could not be received normally. A receiving terminal that has received all packets normally selects one of the receiving terminals for communication connection, and a receiving terminal that has a packet that could not be received normally is connected to the receiving terminal for communication Then, through the steps of acquiring a normal packet based on the header information and updating the stored digital data based on the acquired normal packet, the digital data can be normally received from the transmission server. It is characterized in that the receiving terminal which did not exist complements the missing data of the digital data.

Further, in the digital data transmitting / receiving method of the present invention, the receiving terminal that receives the digital data having the missing data and the receiving terminal that normally receives all the digital data are selectively connected in order of good communication conditions. It is characterized by

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a digital data transmitting / receiving system of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram for explaining the concept of a digital data transmitting / receiving system according to the present invention. In FIG. 1, the digital data transmission / reception system is
A transmitting server 1 that multicasts or broadcasts digital data over a wide area, and a plurality of receiving terminals 2a, 2b ... They are connected by a digital communication network 3 such as a line or a wired communication line.

In FIG. 1, the transmission server 1 has a transmission means (not shown) which is relatively wide area and can be transmitted at high speed, such as satellite digital broadcasting, and can transmit digital data to be transmitted. Broadcasting is carried out by adding error detection information and broadcasting by broadcasting to specific users or broadcasting by broadcasting to unspecified users. On the other hand, each of the receiving terminals 2a, 2b ... 2n has a receiving means (not shown) for receiving the digital data transmitted from the transmitting means of the transmitting server 1. The receiving means of each of the receiving terminals 2a, 2b ... 2n may fail to receive due to external factors such as weather.

Each of the receiving terminals 2a, 2b ... 2n has storage means (not shown), which will be described in detail later, and when receiving digital data from the transmitting server 1, the received digital data and the received digital data Based on the added error detection information, it is confirmed whether or not the digital data was correctly received, and if it is confirmed that the digital data was correctly received, the digital data is stored in the storage means. Further, each of the receiving terminals 2a, 2b ... 2n has a communication means (not shown) such as a wired communication capable of reliable communication.

Then, for example, the communication means of the receiving terminal 2a communicates with the communication means of the transmitting server 1 and the other receiving terminals 2b ... 2n to report or receive the communication status of its own receiving terminal 2a. Digital data is complemented between the terminal 2a and the other receiving terminals 2b ... 2n. Receiving terminal 2
Although the description is centered on a, the same applies to the other receiving terminals 2b ... 2n. In this way, each receiving terminal 2
The a, 2b ... 2n can always receive correct digital data without being affected by external factors such as weather conditions.

Next, the flow of processing in which the transmission server 1 and the reception terminals 2a, 2b ... 2n shown in FIG. 1 transmit and receive digital data will be described in detail. First, a process in which the transmission server 1 transmits digital data to each of the receiving terminals 2a, 2b ... 2n will be described. FIG. 2 is a block diagram showing a detailed configuration of the transmission server shown in FIG. In FIG.
The transmission server 1 includes a digital data input means 11 for inputting digital data to be transmitted to each of the receiving terminals 2a, 2b ... 2n, a digital data / packet converting means 12 for converting the digital data into a packet, and each receiving terminal 2
a, 2b ... 2n, a transmission packet storage means 13 for temporarily storing a packet to be transmitted, and a packet stored in the transmission packet storage means 13 for each receiving terminal 2a,
2b ... 2n, and packet transmission means 14 and transmission server control means 15 for controlling the entire transmission server 1.

In such a system configuration, the digital data transmitted by the transmission server 1 is assigned a different ID for each digital data, and the digital data transmitted can be specified by the ID.
Also, the digital data is divided into small sizes, and header information is added to each of the divided pieces. The digital data to which the header information is added in this way is called a packet.

FIG. 3 is a configuration diagram of a packet transmitted from the transmitting server to the receiving terminal. In FIG. 3, the packet is composed of a part of packet data 21 of digital data which is broadcast information and header information 22. The header information 22 includes a header size 23, an ID 24,
A size 25 of digital data to be transmitted, a packet position 26 indicating the position from the beginning of the digital data of this packet, a packet size 27 of this packet, and a checksum 28 for error detection of digital data are included. .

FIG. 4 is a flow chart showing the flow of digital data transmission processing performed by the transmission server shown in FIG. Therefore, the flow of processing in which the transmission server 1 transmits digital data will be described with reference to the flowchart of FIG. First, when the digital data to be transmitted and the ID of the digital data are inputted from the digital data input means 11 (step S1), the inputted digital data and ID are transmitted to the digital data / packet converting means 12 (step S2). ). Then, the digital data / packet conversion means 12 stores therein the input ID and the size of the input digital data (step S3).

After that, the digital data / packet converting means 12 sequentially cuts the stored digital data from the beginning by a predetermined size and calculates a checksum of the cut digital data (step S).
4). Then, for each of the cut digital data, as header information 22, a header size 23, ID2
4, the size 25 of the digital data, the packet position 26 indicating the position from the beginning of the clipped digital data, the packet size 27 indicating the size of the clipped digital data, and the checksum 28 for error detection of the digital data. Packet data 2 that is added and is broadcast information
Together with 1, one packet as shown in FIG. 3 is generated (step S5). In this way, it is repeated until all the packets are generated (step S6), and when the generation of all the packets is completed (YES in step S6), all the generated packets are stored in the transmission packet storage means 13. (Step S7).

After that, the packet transmitting means 14 sequentially takes out all the packets stored in the transmitting packet storage means 13, and the respective receiving terminals 2 are extracted from the packet transmitting means 14.
packets are transmitted to a, 2b ... 2n (step S
8). In this way, the transmission process is continued until all the packets have been transmitted (step S9), and when all the packets have been transmitted (YES in step S9), the transmission completion data indicating the packet transmission completion notification is transmitted. Receiving terminal 2
a, 2b ... 2n (step S10), and deletes all the packets stored in the transmission packet storage means 13 (step S11).

Next, the flow of operation in which each of the receiving terminals 2a, 2b ... 2n receives digital data and processes it will be described. FIG. 5 is a block diagram showing a detailed configuration of one receiving terminal shown in FIG. Each receiving terminal 2a, 2b ...
Since all of the 2n perform the same operation, the receiving terminal 2a will be taken up as a representative and described in the following description. In FIG. 5, the receiving terminal 2a includes a packet receiving means 31 for receiving the packet transmitted from the transmitting server 1, a received packet storage means 32 for storing the received packet, and a packet / converting means for converting the received packet into digital data. Digital data conversion means 33, digital data storage means 34 for storing correctly received digital data, reception information storage means 35 for storing correctly unreceived digital data and additional information thereof, and others for receiving digital data 2n and the communication means 36 used for communicating with the transmission server 1, and the reception terminal control means 37 for controlling the whole reception terminal 2a.

The communication means 36 may be, for example, a telephone line or a modem. The header information 22 added to the digital data that could not be correctly received includes the ID 24 of the digital data, the packet position 26 indicating the position from the beginning of the digital data of the packet that was not correctly received, and the packet size of the digital data. 27 lists are written.

FIG. 6 is a diagram showing the first half of a flow chart showing the flow of processing of digital data performed by the receiving terminal shown in FIG. 5, and FIG. 7 is a diagram showing the second half of the flow chart of FIG. Therefore, although the flow of the process in which the receiving terminal 2a receives the digital data will be described with reference to the flowcharts of FIGS. 6 and 7, the operation of the other receiving terminals 2b ... 2n is the same as that of the receiving terminal 2a. Is omitted. Note that the packet receiving means 31 and the communication means 36 of the respective receiving ends not shown 2a, 2b ... 2n shown in FIG.

First, the packet receiving means 3 of the receiving terminal 2a
When 1 receives a packet from the transmission server 1 (step S21), the received packet storage means 32 stores the received packet (step S22). Then, it is determined whether or not the packet receiving means 31 has received the transmission completion data indicating the notification of the packet transmission completion (step S2).
3) If the transmission completion data has not been received (NO in step S23), it is determined whether or not the state of not receiving the packet has continued for a predetermined period or more (step S24). In this way, the standby state for a certain period continues until the transmission completion data is received (in the case of NO in step S24).

Here, if the transmission completion data is received (YES in step S23) or if the unreceived state of the packet continues for a certain period or more (YE in step S24).
(In the case of S), it is judged that the reception of the predetermined packet is completed, and the packet temporarily stored in the received packet storage means 32 is transferred to the packet / digital data conversion means 3
3 (step S25). Then, the packet / digital data conversion means 33 calculates the checksum of the packet data and compares it with the checksum of the packet data written in the header information 22 of the packet (step S26).

Then, it is judged whether or not the calculated checksum value and the value written in the header information 22 match (step S27), and if the checksum values of both are different (step S27). In the case of NO in S27), it is determined that the packet has not been correctly received, and the packet is deleted (step S28). On the other hand, if the checksum values of the two match in the comparison result (YES in step S27), the packets are classified based on the value of the ID 24 written in the header information 22 of the packet (step S29). .

Then, the packet / digital data converting means 33, based on the packet position 26 from the beginning of the digital data and the packet size 27 written in the header information 22, for each packet having the same ID 24 value. Restore the original digital data (step S3)
0). At this time, based on the packet position 26 from the beginning of the digital data written in the header information 22 of all the packets having the same ID 24 value and the packet size 27 of this digital data, the packet which cannot be correctly received is It is determined whether or not there is (step S3
1). If there is no packet that was not correctly received (NO in step S31), the receiving terminal 2a
All receive correct packets (step S
32), the process ends.

On the other hand, if there is a packet that was not correctly received (YES in step S31), the packet that was not correctly received is left empty (step S33), and the digital data storage means 34 is empty. The packet position 26 and the packet size 27 from the beginning of the digital data (that is, the portion which was not correctly received) are stored (step S34). In this way
It is determined whether or not the processing has been completed for all the packets having the same ID 24 value (step S35), and the processing is repeated until all the processing is completed.

Next, moving to FIG. 7, it is judged whether or not there is a vacant portion in the packet of the received digital data (step S36), and if there is no vacant portion in the received digital data. (NO in step S36), all the receiving terminals 2a have received the correct digital data (step S37), and the process ends.

On the other hand, if there is a vacant portion in the received digital data (YES in step S36), information indicating that there is a vacant portion in the digital data is added to the header information 22 and the received information storage means is added. It is stored in the memory 35 (step S38). Further, the digital data in the process of being restored, which has an empty portion, is stored in the reception information storage means 35 (step S39). When digital data is stored in the reception information storage means 35 in this way, there is a vacant portion in the digital data, so the communication means 3 is used to complement the vacant portion of the digital data.
6 is used to connect to another receiving device (for example, 2b) (step S40).

Next, if the connection to another receiving device (for example, 2b) is successful, the digital data is stored in the receiving information storage means 35 based on the information about the empty portion of the digital data which is put together with the digital data. ID and the list of empty parts are taken out (step S4)
1). Then, the ID of the extracted digital data and the list of empty portions are transmitted to the other receiving terminal 2b that is connected, and the complementary data is requested (step S4).
2).

Then, it is judged whether or not the complementary data is sent from the other connected receiving terminal 2b (step S4).
3) If the complementary data is obtained from the other receiving terminal 2b (YES in step S43), the complementary data is embedded in the empty portion of the digital data stored in the reception information storage means 35. , The digital data is updated by supplementing the information about the vacant portion (step S44). By such processing, it is determined whether or not all the complementary data are filled in the vacant portions of the digital data (step S45), and when all the vacant portions of the digital data are filled with the complementary data (step S45).
In the case of YES), since the restoration of the digital data is completed, the restored digital data is stored in the digital data storage means 34 (step S46).

Then, the digital data stored in the reception information storage means 35 is deleted (step S47), and further, all the packets corresponding to the IDs in which the digital data are vacant are deleted from the reception information storage means 35 (step S47). S48). As a result, the receiving terminal 2a can obtain correct digital data with no missing, because the vacant portion of the digital data is complemented by the data of the other receiving terminal 2b (step S49).

In step S43, the other connected receiving terminal 2b returns an error signal, and the receiving terminal 2a receives the error signal.
However, if the complementary data cannot be obtained from the other receiving terminal 2b (NO in step S43), the receiving terminal 2a cannot receive the correct digital data from the other receiving terminal 2b. According to the connection order, another receiving terminal (for example, 2n) is determined as a connection destination, and an attempt is made to request complementary data from another receiving terminal 2n (step S50). The following processing is the same as the flow for obtaining complementary data from the other receiving terminal 2b after step S43, and therefore description thereof will be omitted.

Note that the connection order of the receiving terminals that are connected to complement the vacant portion of the digital data is managed in a table for each receiving terminal. FIG. 8 is a management table showing the connection order of receiving terminals. That is, the management table in FIG. 8 shows the order in which one receiving terminal X connects another receiving terminal using the communication means. For example, the receiving terminal X
In order to obtain complementary data, first, by using the telephone number, connection ID and password of the receiving terminal A,
Connect to the receiving terminal A and try to acquire complementary data. If no complementary data is obtained, secondly, using the telephone number of the receiving terminal B, the connection ID, and the password,
Connect to the receiving terminal B and try to acquire complementary data. Furthermore, if supplementary data is not obtained, thirdly, using the telephone number of the receiving terminal C, the connection ID, and the password,
Connect to the receiving terminal C and try to acquire complementary data.

The above-described embodiment is an example for explaining the present invention, and the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the invention. is there. For example, each receiving terminal registers some receiving terminals for performing communication in order to acquire correct digital data when it cannot correctly receive digital data. At this time, communication cost, communication speed, etc.
Each receiving terminal can be registered in order for convenience. As a result, the receiving terminal that cannot correctly receive the digital data can automatically connect to the receiving terminal having the lowest communication cost or the receiving terminal having the high communication speed in order according to the preset registration order. Then, it is possible to acquire correct digital data from another receiving terminal while confirming whether the connected receiving terminal can correctly receive the digital data. As a result, each receiving terminal can be realized with an optimal communication cost and communication time in order to complement the failure of multicast or broadcast.

It is also possible to provide a receiving terminal monitoring means for constantly monitoring the receiving states of a plurality of receiving terminals, and store the communication cost when two arbitrary receiving terminals communicate with each other in the receiving terminal monitoring means. . As a result, all the receiving terminals monitored by the receiving terminal monitoring means report to the receiving terminal monitoring means using the communication means whether or not the digital data has been correctly received. Then, the receiving terminal monitoring means can select and notify the receiving device, which cannot receive the digital data correctly, to the receiving device having the lowest communication cost among the receiving terminals that can correctly receive the digital data. . As a result, it becomes possible to construct a digital data transmission / reception system capable of complementing a communication failure of multicast or broadcast while minimizing the communication cost.

[0042]

As described above, when digital data is transmitted in a wide area and at a high speed in conventional satellite broadcasting, the reception data may be lost due to external factors such as weather. The terminal may occur. That is, in conventional data communication such as digital broadcasting, digital data that is multicast or broadcast may be missed depending on environmental conditions. However, according to the digital data transmission / reception system of the present invention, since the receiving terminals complement each other's missed digital data, all the receiving terminals can receive the correct digital data.

Further, according to the digital data transmission / reception system of the present invention, the receiving terminal can supplement the missing data with only one transmission without increasing the number of times of transmitting the same digital data from the transmitting device. At this time, it is not necessary to prepare a server dedicated to data complement. In this way, each receiving terminal can perform data complementation only by receiving digital data once, so that the communication cost for data complementation can be kept low.

For example, when there are a plurality of receiving terminals in the same city, the receiving terminal having the data loss complements the receiving terminal if the receiving terminal can correctly receive the data in the same city. Data can be acquired. Therefore, the receiving terminal that has failed to receive the data can supplement the data at the communication cost of the local telephone bill and receive the satellite broadcast with the correct digital data. Also,
If the connection order of the receiving terminals to be connected for communication for data complementation is set in the ascending order of communication cost, the digital data can be complemented at a lower communication cost. In addition, when many receiving terminals exist in a wide area, if all receiving terminals perform data supplement through the same server, there will be receiving terminals that require long-distance call charges. Since there is a server for each of them, any receiving terminal can perform data complement at about the local telephone charge.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining the concept of a digital data transmission / reception system according to the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a transmission server shown in FIG.

FIG. 3 is a configuration diagram of a packet transmitted from a transmission server to a reception terminal.

FIG. 4 is a flowchart showing a flow of digital data transmission processing performed by the transmission server shown in FIG.

5 is a block diagram showing a detailed configuration of one receiving terminal shown in FIG. 1. FIG.

FIG. 6 is a diagram showing the first half of a flowchart showing the flow of processing of digital data performed by the receiving terminal shown in FIG. 5;

FIG. 7 is a diagram showing the latter half of the flowchart of FIG.

FIG. 8 is a management table showing a connection order of receiving terminals.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sending server, 2a, 2b-2n ... Receiving terminal, 3 ... Digital communication network, 11 ... Digital data input means, 12 ...
Digital data / packet conversion means, 13 ... Transmission packet storage means, 14 ... Packet transmission means, 15 ... Transmission server control means, 21 ... Packet data, 22 ... Header information, 23 ... Header size, 24 ... ID, 25 ... Digital data , 26 ... Packet position, 27 ... Packet size, 28 ... Checksum, 31 ... Packet receiving means, 32 ... Received packet storage means, 33 ... Packet / digital data converting means, 34 ... Digital data storage means, 35 ... Reception Information storage means, 36 ... Communication means, 37 ...
Receiving terminal control means

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5C063 AA01 AB03 AB07 AC01 AC05                       AC10 CA23 CA36 CA40 DA03                       DA07 DA13 DB10                 5K030 GA11 HB01 HB02 JT04 LA01                       LD06 LD07 MB13

Claims (9)

[Claims] 1. A digital data transmission / reception system, comprising one transmission server and a plurality of reception terminals, wherein digital data is distributed from the transmission server to the plurality of reception terminals. In order for the receiving terminal that has missing data in at least part of the data to select one of the receiving terminals that has received all the digital data normally and to complement the missing data from the digital data of the selected receiving terminal A digital data transmission / reception system characterized by being configured to obtain the digital data of and to complement the received digital data. 2. The transmission server adds error detection information for determining whether or not the digital data has been normally received to the digital data to be transmitted, and transmits the digital data. The digital data transmission / reception system according to claim 1, wherein the presence or absence of missing data is confirmed based on error detection information added to the received digital data. 3. A digital data transmission / reception system, comprising one transmission server and a plurality of reception terminals, wherein digital data is distributed from the transmission server to the plurality of reception terminals, wherein the transmission server is digital data for transmission. Is converted into a plurality of packets to which header information for identifying the digital data is added, and packet transmitting means for sequentially transmitting the plurality of packets to the plurality of receiving terminals. Each of the plurality of receiving terminals can normally receive the packet receiving means for sequentially receiving the packets transmitted from the transmitting server, the packet / digital data converting means for converting the received packets into digital data, respectively. Digital data storage means that stores digital data and whether it can be received normally The received digital data and its header information, and a communication means for communicating with the other receiving terminal that has received the digital data and the transmission server. At least a part of the received digital data is missing. A receiving terminal having data, using the communication means, transmits information of the digital data stored in the received information storage means and its header information to the receiving terminal that has normally received all the digital data, A digital data transmission / reception system characterized by obtaining normal digital data from a receiving terminal and updating the digital data stored in the digital data storage means. 4. The communication means selectively connects a receiving terminal that receives digital data having missing data and a receiving terminal that normally receives all digital data in order of good communication conditions. The digital data transmitting / receiving system according to claim 3. 5. A receiving terminal monitor for monitoring the reception status of at least two or more receiving terminals among the plurality of receiving terminals, and storing the communication cost when any two receiving terminals to be monitored communicate. Means, all the receiving terminals monitored by the receiving terminal monitoring means,
Via the communication means, when notifying the receiving terminal monitoring means whether or not the digital data can be normally received, the receiving terminal monitoring means, to the receiving terminal that could not normally receive the digital data, The receiving device having the lowest communication cost among the receiving terminals that can normally receive the digital data is selected and notified.
The digital data transmission / reception system described in. 6. A digital data transmission / reception method comprising one transmission server and a plurality of reception terminals, wherein digital data is distributed from the transmission server to the plurality of reception terminals, wherein the received digital data among the plurality of reception terminals is received. For the receiving terminal that has missing data in at least a part of, to select one receiving terminal from the receiving terminals that normally received all the digital data, and to complement the missing data from the digital data of the selected receiving terminal A method for transmitting and receiving digital data, which comprises acquiring digital data and complementing the received digital data. 7. The transmission server adds error detection information for determining whether or not the digital data is normally received to the digital data to be transmitted, and transmits the digital data. 7. The method of transmitting and receiving digital data according to claim 6, wherein the presence or absence of missing data is confirmed based on error detection information added to the received digital data. 8. A digital data transmission / reception method comprising: one transmission server and a plurality of reception terminals, wherein the transmission server distributes digital data to the plurality of reception terminals, wherein the transmission server transmits digital data to be transmitted. , A step of converting the plurality of packets with header information for identifying the digital data added, and a step of sequentially transmitting the plurality of packets to the plurality of receiving terminals, the plurality of receiving terminals , Sequentially receiving packets transmitted from the transmission server, determining whether there are any packets that could not be received normally, and converting the packets that were normally received into digital data and storing them To store packet and header information that could not be received normally, and The receiving terminal that has packets that could not be received in the step of selecting one of the receiving terminals that normally received all the packets to establish a communication connection, and the receiving terminal that has the packets that could not be received normally establish a communication connection From the received terminal, the normal packet is acquired from the transmission server through the step of acquiring a normal packet based on the header information and the step of updating the stored digital data based on the acquired normal packet. A digital data transmission / reception system, characterized in that a receiving terminal that cannot receive digital data complements missing data of digital data. 9. The receiving terminal that receives digital data having missing data and the receiving terminal that normally receives all digital data are selectively connected in order of good communication conditions. Digital data transmission / reception method described in.