JPH09266493A - Continuous data delivery method and system - Google Patents

Abstract

(57) Abstract: Continuous data such as AV information can be continuously processed without error even when data loss occurs due to deterioration of network data transmission error or temporary deterioration of reception performance at terminals. An object of the present invention is to provide a continuous data delivery method and system capable of delivering high quality to a large number of terminals. According to the present invention, in a server, the same block is transmitted to a terminal a plurality of times by utilizing a communication idle time caused by a difference between a coding rate of continuous data and a transmission speed of a communication network, and the first block is delivered. When a dropout occurs, the data of the subsequent block is supplemented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous data delivery method and system, and more particularly to an AV (Audio-Visua) during shooting.
l) Information, character / numerical information (hereinafter referred to as continuous code information) coded according to a specific format that is input continuously or at an appropriate frequency, or AV information stored in a large capacity database The present invention relates to a continuous data delivery method and system for delivering continuous code information to a terminal and providing continuous data for immediate reproduction.

The present invention is also applied to a system in which a terminal stores received information received from a server in a large-capacity database for reuse.

[0003]

2. Description of the Related Art As a conventional continuous data delivery technology,
There is a method of simply transmitting delivery data from a server to a plurality of terminals when delivering data. For example, what is performed in the MBONE experiment on the Internet is known, which uses multicast delivery (delivery to a terminal group). This delivery method is
Since only the delivery is performed, the processing for the missing data is not performed.

FIG. 16 shows a conventional data delivery sequence to a plurality of terminals. In the figure, the buffer used for communication is a block buffer. The encoding / decoding of information is performed by an encoder / decoder. Furthermore, during the processing of encoding / decoding and communication, A
A P buffer is provided as an intermediate buffer. conventionally,
Some do not use the application buffer.

In FIG. 16, when AV data is photographed in real time using a photographing device or a microphone, the AV data is accumulated in an encode buffer, and A
It is V-segmented and stored in the application buffer. When delivering this from the server to the terminal,
It is divided into delivery blocks and accumulated in a block buffer, and at the time of delivery, each block is delivered to a plurality of terminals.

On the terminal side, the block received from the server is stored in the block buffer, is stored in the application buffer for each delivery block, and is decoded and reproduced on the output device. In the case of continuous code information, it may be displayed on an output device after being subjected to processing such as numerical display of a graph.

Further, as a conventional method, there is also a method of simply delivering given data as it is without dividing it into blocks. In either of the block-based delivery and the data transfer as it is, conventionally, the data is delivered only once without using even when the communication idle time occurs.

A packet is about 1 Kbyte, a block is about several Mbytes, and an AV segment is about several hundred bytes.

[0009]

However, as described above, conventionally, the delivery data is lost due to the transmission error or loss of data on the network or the buffer overflow at the receiving terminal. If it happens,
At the terminal, the quality of the delivery information deteriorates because the content is reproduced while it is missing. Even when the terminal stores the received data in the database, it remains deteriorated at the time of reception.

Therefore, in the above-mentioned conventional method, since it is not possible to cope with a partial loss of delivery data, the quality of the received information is deteriorated due to the deterioration of the quality of the network and the loss of data at the terminal, and high quality information is obtained. There is a problem that playback cannot be performed. The present invention has been made in view of the above points,
For continuous data such as information and continuous code information, even when data loss occurs due to deterioration of network data transmission error or temporary deterioration of reception performance at terminals, continuous data is error-free and high quality An object of the present invention is to provide a continuous data delivery method and system capable of delivering to a terminal.

[0011]

SUMMARY OF THE INVENTION The present invention is a continuous data delivery method for delivering information continuously from a server to at least one terminal via a communication network. The same block is transmitted to the terminal a plurality of times by utilizing the communication idle time caused by the difference in the transmission speed of the communication network, and when a loss occurs in the first block delivery, the data of the subsequent block is supplemented.

FIG. 1 is a diagram for explaining the principle of the present invention. According to the present invention, in a server, continuous data is delivered to a terminal in block units to which sequence numbers are added and packet units in which blocks are subdivided (step 1),
The terminal receives the data in the block unit and the packet unit delivered from the server (step 2), and records the success or failure of the reception in the data packet unit based on the sequence number of the packet of the packet unit data ( In step 3), the record of the success or failure of reception is collated with the sequence number of the packet just received, and if the received data packet has not been received previously, it is stored in the block buffer (step 4) and the received data packet is received. If is received, it is discarded without being stored (step 4).

Further, according to the present invention, a plurality of block buffers are prepared in the server, information from the outside is read in advance and stored in the plurality of block buffers, and a block delivery space to the terminal occurs. Control not to. Further, according to the present invention, when the terminal receives the delivery start notification from the server, the terminal returns a response only to the delivery start notification received first in the data delivery.

FIG. 2 is a block diagram showing the principle of the present invention. The present invention is a continuous data delivery system including a communication network, a server connected via the communication network, and at least one terminal to which data is continuously delivered from the server via the communication network. Therefore, application management means 110 and 310 for managing delivery / reception of continuous data divided into block units.
And a delivery processing means 120, 320 that divides a block into packets and performs delivery processing in packet units.
00 and terminal 300.

Further, the delivery processing means 120 of the server 100 described above includes the duplicate delivery means 140 for delivering the continuous data in a duplicated manner to the terminal in a block unit to which a sequence is added and a packet unit in which the block is subdivided. Also, the terminal 300 refers to the success / failure recording means 350 for recording the success / failure of reception in data packet units based on the sequence number and the success / failure recording means 350, and if the received data packet has not been previously received. It includes a packet storing / discarding unit 380 which stores and discards a received data packet.

Further, the delivery processing means 120 of the server 100 delivers the delivery start notification packet to the terminal prior to the next block delivery for each of the first data delivery and the block delivery. 160, and a delivery completion notifying means 150 for delivering a delivery completion notification packet to the terminal when the delivery is completed.

Further, the delivery processing means 3 of the terminal 300 described above.
20 includes a response unit 360 that returns a response to the server 100 only when the delivery start notification is the first notification of data delivery when the delivery start notification is received from the server. Further, the delivery processing means 120 of the server 100 has a plurality of block buffers and precedes the reading from the application buffer of the application management means.
A first preceding storage means for storing in the block buffer is included.

Further, the application management means 310 of the terminal 300 has a plurality of application buffers, and includes a second preceding storage means for performing the reading from the block buffer of the delivery management means 320 in advance and storing it in the application buffer. .

As described above, the present invention is caused by the difference between the encoding rate of information and the transmission rate of the communication network when the information is continuously delivered from the server to the plurality of terminals via the communication network. Even if the same block is sent to the terminal multiple times by using the communication idle time and a dropout occurs in the first block delivery, the same block is sent multiple times, so it is necessary to supplement with the data of the block. You can

Further, according to the present invention, the record of the success or failure of the reception is made by recording the success or failure of the reception of the data packet unit on the terminal side based on the sequence number of the packet of the data of the packet unit received from the server. Then, if the received data packet has not been received, it is stored in the block buffer for reception processing, and if the data packet has been received, it is discarded without being stored.
It is possible to reliably complement missing or missing blocks. In particular, since data storage is determined only by referring to the packet sequence number, an extra storage area or data copy between memories is unnecessary even if duplicate reception is performed.

Further, according to the present invention, a plurality of block buffers are prepared in the server, information from the outside is read in advance, and the information is stored in the plurality of block buffers. Does not occur. Further, according to the present invention, when the terminal receives the delivery start notification from the server, the terminal returns a response only to the first delivery start notification of the data delivery, and the delivery start notification in the second block and subsequent blocks is returned. By omitting the response and sending the delivery start notification to the terminal in a duplicated manner, it is possible to save the data in the same manner as described above and shorten the communication time of the entire data.

Further, according to the present invention, when the delivery completion notification is received from the server in the terminal, a record of the success or failure of the reception is recorded.
By transmitting the data to the server, it becomes possible to use it as billing information for the data received on the terminal side.

[0023]

FIG. 3 shows a system configuration to which the present invention is applied. In the information communication system shown in the figure, the server 100 is connected to an encoder 107 that encodes information acquired from a camera / microphone 106 and a database 108 that stores encoded AV information or continuous code information. It The continuous code information may be sequentially stored in the database from the outside.

Further, each of the terminals 300 ₁ , 300 ₂ , ..., 3
An output device 301 that reproduces and outputs the decoded information and a database 302 are connected to 00 _n . In addition, the server 100 and the plurality of terminals 300 ₁ , 300 ₂ ,
, 300 _n are connected to a wired or wireless communication network 200, and the terminals 100 ₁ , 300 ₂ , ..., 3 from the server 100 via the communication network 200.
Data is delivered to 00 _n .

The information input from the camera / microphone 106 is encoded by the encoder 107 and taken into the server 100. Information is stored in advance in the large-capacity database 108.
It may be loaded into the server 100 from there. On the terminal 300 side, the information delivered from the server 100 is immediately output to the output device 301 such as a monitor or a speaker. The terminal 300 may store the received information in the database 302. The above is an example of using a normal continuous data delivery service.

FIG. 4 shows the configuration of the server of the present invention. The server 100 shown in FIG.
0, a delivery management unit 120, and a communication control unit 130. The application management unit 110 includes an application buffer 111 and an application processing unit 112 that manages continuous data in the application buffer 111 into blocks. The delivery management unit 120
The block buffer 121 and the block buffer 12
It has a delivery processing unit 122 that transfers data in one block unit and subdivided packet unit and requests the application processing unit 112 for the next block each time one block delivery is completed.

FIG. 5 shows the configuration of the delivery processing unit of the server of the present invention. The delivery processing unit 122 includes a packet delivery processing unit 1221 including a packet management table 1223 and a delivery start / end processing unit 1222. The packet delivery processing unit 1221 divides and delivers the block for each packet, and manages the success or failure of the delivery in the packet management table 1223. The delivery start / end processing unit 1222 manages the start and end of packet delivery.

FIG. 6 shows an example of the packet management table of the server of the present invention. Packet management table 1 shown in FIG.
223 is a block buffer 12 for each packet number.
1 manages each packet position. As shown in the figure, the packet management table 1223 assigns a sequence number (packet number) to each packet, and also specifies a storage position on the memory for each packet. In terms of program implementation,
A fixed-size packet storage area is provided for each number, but the storage location in memory is often not expressed explicitly.

FIG. 7 shows the configuration of the terminal of the present invention. The terminal 300 shown in FIG.
Delivery management unit 320, communication control unit 330, and decoder 34
One. The application management unit 310 includes an application processing unit 312 and an application buffer 3.
11, and acquires the information passed from the delivery management unit 320 and stores it in the application buffer 311.

The delivery management unit 320 has a delivery processing unit 322 and a block buffer 321, and the delivery processing unit 322 is
Data reception processing is performed from the server 100 via the communication control unit 330 in block units and packet units, and the received block is passed to the application processing unit 311 of the application management unit 310 each time block reception is completed.

The decoder 340 decodes the coded information passed from the application management unit 310, stores it in the decode buffer 341, and outputs it to the external AV or the database 302. FIG. 8 shows the configuration of the delivery processing unit of the terminal of the present invention. Delivery processing unit 32
2 has a packet delivery processing unit 3221 including a packet management table 3223 and a delivery start / end processing unit 3222.

As shown in FIG. 9, the packet management table 3223 indicates the position of each packet in the block buffer 321 for each received packet number, and further manages whether each packet has been received or has not been received. In this way terminal 3
The packet management table 3223 of 00 also has a field for recording whether or not a packet has been received for each packet.
It has for each packet. The success / failure is indicated by ◯ × in the figure, but is represented by one bit of bit ON (= 1) or bit OFF (= 0) in implementation. The packet sequence number is an integer, and if a 10 Mbyte block is divided into 1 Kbyte-long packets, the number is from 1 to 100.
Up to number 00. The format of the storage location follows the usual format used in each computer system or programming language that describes the table.

Next, a series of schematic operations of the above configuration will be described. FIG. 10 is a diagram for explaining a series of operations of continuous delivery according to the present invention. Application processing unit 112
When receiving a delivery request from the outside, divides the data in the application buffer 111 into blocks and notifies the terminal 300 of a delivery start notification.

When the delivery start / end processing unit 3222 of the delivery processing unit 322 of the terminal 300 receives the delivery start notification, the delivery management unit 322 of the terminal 300 prepares the block buffer 321 and the application processing unit 312
The application buffer 311 and the block management table 3223 are prepared to prepare for reception.

Application processing unit 1 of server 100
12 transfers the data to the delivery processing unit 122 in block units. The delivery processing unit 122 prepares the block buffer 121 and performs block transmission a plurality of times. In the figure, the number of times of duplication is three.

When the communication control section 330 of the terminal 300 receives the data packet, the packet management table 3223 is received.
If it is not received (when the packet is received for the first time), the packet is referred to as the block buffer 321.
To be stored. If already received, the packet is discarded without being stored.

By the operation of the terminal 300, the success rate of receiving lost packets can be improved. Moreover, since the already received packet is immediately discarded, no extra storage area or data copy between memories is required. The communication control units 130 and 330 of the server 100 and the terminal 300 perform the connection process with the network, the packet transfer process, the detection of the bit error error of the packet, and the discarding of the error packet.

As described above, in the present invention, the same block is delivered to each terminal 300 a plurality of times (three times in the figure). The terminal 300 receives the blocks in duplicate. As will be described later, in the second and subsequent delivery of the same block, only unreceived packets are stored in the block buffer 321 and already received packets are immediately discarded.

Although the same drawing shows the case where the duplicate delivery is performed three times, the duplicate delivery may be performed twice depending on the difference between the information encoding / decoding rate and the data transmission rate available in the network 200. In addition, it may be four times or more. As described above, according to the present invention, in the server 100, the free time of the next new block delivery after the block delivery is used for the duplicate delivery, and the terminal 300 performs the duplicate receiving process based on the packet sequence number. Efficient duplicate data delivery can be realized and the quality of received data can be improved.

Multicast transmission to a plurality of terminals (broadcast transmission of data specifying a group) can be realized by using an OS (operating system) capable of multicast communication. That is, as the communication control units 130 and 330 of the server 100 and the terminal 300, for example, UDP (User Datagram Protocol) and IP (Inter
This can be realized by using an OS capable of net protocol) protocol processing. In particular, an OS capable of processing an IP group address (class D address) is used.
UDP processing also includes detection of bit errors in received packets and discarding of bit error packets.

In addition, as an information encoding technique, a highly efficient and low bit rate encoding method MPEG standardization and MPE
Commercialization of encoder and decoder based on G method (L
(SI, communication board), while high-speed network technologies such as frame relay and ATM are becoming available for networks. The present invention utilizes such a low bit rate information coding technique and the idle time of data delivery generated by using a high speed network for duplicate delivery. In addition, continuous code information that can be encoded at a low bit rate such as character / numerical value information can be similarly duplicated by using a high speed network. Here, a decoder having the same decoding rate as the encoder used for encoding is also normally used for decoding information.

Examples of encoding and decoding rates are shown below. MPEG1: about 1.5 Mb / s; MPEG2: about 6 Mb / s; MPEG4: about 64 Kb / s; character code: about 6.4 Kb / s (400 characters / s, 2-byte code): network communication speed An example is shown below. ATM: 156 Mb / s, 622 Mb / s: Ethernet L
AN: 10 Mb / s, FDDI-LAN: 150 Mb / s:
High-speed leased line, frame relay: 1.5Mb / s, 6Mb / s
etc:

[0043]

Embodiments of the present invention will be described below with reference to the drawings. First, the server 100 and the terminal 3 shown in FIGS.
00 will be described. Both the server 100 and the terminal 300 have application buffers 111 and 311 in application management units 130 and 330, respectively.
Then, the application processing unit 112 passes the delivery data to the delivery processing unit 122 in block units. Delivery management unit 12
0 has the block buffer 121, and in the server 100, the delivery processing unit 122 divides the block of the block buffer into data packets, and delivers the data via the communication control unit 130.

In the terminal 300, the delivery processing unit 322 determines whether the data packet received via the communication control unit 330 should be received or discarded, and the block buffer 321.
To be stored. The application processing unit 322 receives the received data block when all the packets are prepared.
Stored in the application buffer 311 via.

Application buffers 111 and 311
Has a size larger than that of the block buffers 121 and 321. On the server 100 side, the AV segments passed from the encoder 107 are sequentially accumulated, and the data (AV
The (segments) are consumed for delivery in block units via the application processing unit 112 in the order of accumulation.

On the terminal 300 side, the delivery processing unit 1 of the server
The blocks received from 22 are sequentially stored in the application buffer 311 via the delivery processing unit 322 and the application processing unit 312, and are sequentially output in the order in which they are stored in the AV segment or consumed for storage in the database 302. Go.

In this embodiment, the encoder 107 is placed outside the server 100, and the decoder 340 is the terminal 300.
The structure is provided inside. Of course, the encoder 107 is integrated with the server 100, and the decoder 340 is connected to the terminal 30.
A configuration provided outside 0 is also possible.

Since the encoder 107 usually has a heavier processing load, an independent structure is often adopted, and the decoder 340 is often incorporated into a terminal as an LSI or a board as it is commercialized. It has the configuration shown. When the delivery is started from the server 100 to the terminal 300, a delivery start notification packet is delivered from the delivery start / end processing unit 1222 of the delivery processing unit 122 of the server 100 before the data delivery.

FIG. 11 shows the structure of a delivery start notification packet according to an embodiment of the present invention. This is notified from the server 100 to the terminal 300 prior to the next block delivery at the very beginning of data delivery and each block delivery. For efficiency, multiple terminals shall be multicast. The second or more delivery start notification packet is provided just in case to notify the terminal 300 of the start of the next block delivery. The terminal 300 can obtain the trigger for the completion of the block delivery for one time and the preparation for the next block reception even when the packet reception for one block is completed or the timeout for the reception for one block.

The delivery start notification packet 600 shown in the figure comprises a terminal destination 601, a packet ID 602 indicating the packet type (being a delivery start notification packet), and delivery information 603. The delivery information 603 includes a block size 605 and a block number 606 indicating the number of block delivery.

Regarding the code length of the block number 606,
When encoded with 16 bits, up to 65536 can be expressed by the power of 2 and approximately 655.36 G for a 10 Mbyte block.
It can handle up to bytes. If it is encoded with 32 bits, it can express 4,294,967,29 as 2 32, and 10M
A byte block can handle up to approximately 42949.6 Tbyte. Even when using a short 100 Kbyte block,
When the block number 606 is encoded with 16 bits and 32 bits, the data capacity up to about 6.55 Gbyte and about 429 Tbyte can be handled, respectively, and there is no problem in practical use.

For the delivery start notification packet delivered from the server 100, the terminal returns a response for confirmation. However, the delivery start notification packet is delivered at the start of delivery and at the head delivery of the block, but the response from the terminal 300 is returned only at the start of delivery, and in the delivery of blocks other than the first block, the response is returned. Don't wait.
Instead, the notification packet is transferred in duplicate, which is effective for the notification packet loss in the network or the like. If a fixed value is also used as the block size, the block size notified by the first delivery start notification packet is fixedly used.

FIG. 12 shows the data structure of a data packet according to an embodiment of the present invention. The data packet shown in the same figure is a packet divided into blocks and sent from the server 100 to the terminal 300. The data packet D00 includes a terminal destination D01, a packet type D02, a packet number D0B,
It is composed of a packet number D0P and user data D-3. In the case of multi-destination delivery, a group address is used as the terminal destination D01. The packet type D02 includes
It is shown to be a data packet. Block number D
The block number (sequence number) of the delivery start notification packet shown in FIG. 11 is set in 0B. The packet number D0P is encoded with the sequence number of the packet. Data obtained by dividing a block is set in the user data section D03.

The block number is used here.
This is because when the terminal 300 is receiving a series of data packets and a packet of a block which has already been subjected to the reception process before the reception block is mixed in, this packet is determined by the block number and discarded.

FIG. 13 shows the structure of a delivery completion notification packet according to an embodiment of the present invention. Delivery completion notification packet F00
Has a terminal destination F01 and a packet type indicating a delivery completion notification. In case of delivery to multiple terminals,
A group address is used as the terminal destination F01.

The operations of the server 100 and the terminal 300 of this embodiment will be described below with reference to FIGS. 14 and 15. FIG. 14 is a flowchart of the delivery procedure of the server according to the embodiment of the present invention. Step 801) From the outside of the server 100 to the server 10
A data delivery instruction is issued to the application processing unit 112 of 0. At this time, a group of terminals 300 and continuous data to be transmitted are designated.

Step 802) The server 100 prepares the application buffer 111 in the application management unit 110 as a preparation for starting the delivery. Server 1
In the delivery management unit 120 of 00, the block buffer 1
21 and the packet management table 1 in the packet delivery processing unit 1221 according to the block size and the packet size.
223 is prepared. This block bufferer 121 is premised on that an area in which the available memory sizes of the server 100 and each terminal 300 are taken into consideration is secured in advance in the memory.

Step 803) The application processing section 112 instructs the delivery processing section 122 to start delivery. As a result, the delivery start / end processing unit 1222 generates the delivery start notification packet 600 and transmits it to the terminal 300 by multicast. Step 804) The delivery start / end unit 1222 waits until the responses from the respective terminals to the delivery start notification packet are complete. When all the responses from the terminal 300 are collected, or when the time limit is reached due to timeout,
The members of the terminal 300 to be delivered are determined. This member is the range of the group specified in step 801.
Also, at this time, the server 100 uses the external encoder 10
7 is notified, and input and encoding of information from the outside starts. The encoded continuous data is sequentially stored in the application buffer 111.

Step 805) The application buffer 1 is stored in the block buffer 121 of the delivery management unit 120.
Take in 1 block from 11. Step 806) The delivery management unit 120 divides one block of the block buffer 121 into packets and delivers them. The communication control unit 130 is provided to a plurality of terminals by using multicast.
To ship via.

Step 807) Further, the delivery management unit 12
In 0, the same block is duplicated and delivered a prescribed number of times. (Step 808) Subsequently, it is determined whether there is a next block delivery. Delivery start / end processing unit 1222
Determines the end of delivery by notifying the end from the application processing unit 112 or by time-out. If it is ended, the process proceeds to step 810, and if it is continued, the process proceeds to step 809.

Step 809) In case of continuation, the delivery start / end processing unit 1222 increments the block number, sends the delivery start notification packet 600, and the next block is delivered to each terminal continuously. Is notified, and the process proceeds to step 805 to proceed to delivery of the next block. At this time, step 803 for making the first notification
Unlike the processing of (1), the response from the terminal 300 does not wait, and the time to the next block retransmission is shortened by shifting to the next retransmission immediately. In this case, by sending a plurality of delivery start notification packets to each terminal, it is possible to deal with the loss of the notification packet on the network or the like.

Step 810) When the delivery start instruction of the next block is completed, the delivery start / end processing unit 1222
Generates a delivery end notification packet F00, and the terminal 300
Deliver to. In the case of multiple terminals, multicast is used for delivery. Here, the success or failure of the reception of each terminal 300 can be recorded by providing the procedure of the response from each terminal 300. This record is administratively effective when charging for information delivery. Of course, from the server 100 to the terminal 30
It is possible to implement a procedure in which only the notification to 0 is made and no response is made from the terminal 300. If all responses are received or if a time-out occurs, the process ends.

The above processing is performed by one block buffer 1
21 has been described as an example, a plurality of block buffers are prepared and the application buffer 1
It is also possible to read from 11 to the spare block buffer 121 in advance. This leads to step 8
It is possible to control so that there is no empty transmission for the processing of 05.

Next, the procedure of the terminal 300 corresponding to the delivery procedure of the server 100 will be described. FIG. 15 is a flowchart of the delivery processing procedure of the terminal according to the embodiment of the present invention. Step 901) In the terminal 300, the delivery start / end processing unit 3222 of the delivery processing unit 322 uses the server 100.
Upon receiving the delivery start notification packet 600 delivered from, the application processing unit 312 is notified.

Step 902) Upon receiving the delivery start notification, the application processing unit 312 prepares the application buffer 311 and confirms the preparation to the decoder 340, the external output device 301, and the database 302. The delivery management unit 320 prepares a block buffer 321 of the block data of the delivery information 603 and a packet management table 3223. Packet management table 322
3 is determined by the block size and the packet size.
In this embodiment, it is assumed that the block size is notified by the delivery start notification packet 600, and the packet size is predetermined by the system.

Step 903) The delivery processing unit 322 of the terminal 300 sends a response to the delivery start notification to the server 100.
Return to. . Step 907) After receiving the delivery start notification, the packet reception waiting state is entered. When the data packet is received, the process shifts to the receiving process of one data packet in step 910. When all the packets of one block are prepared, when the delivery start notification packet is received or when the time-out occurs while waiting for the data packet, the process proceeds to step 920.

(Step 910) The storage / discard processing of one data packet is performed in the following steps 911, 912, 9
This will be described with reference to FIG. In this step, in the delivery of each block, only the duplicated second and subsequent duplicated blocks are performed, and all the first blocks are received, so that the collation processing of the packet management table 3223 is not duplicated. It can also be omitted for blocks of. In this case, one data packet may be provided with a 1-bit field in the packet structure to distinguish it from the second and subsequent packets.

Step 911) The packet management table 322 using the packet number of the received 1 packet as a key
It is determined whether or not the packet of No. 3 has not been received (whether it is received for the first time this time). If not received, step 9
If it has already been received, step 9 is performed.
Go to step 13. At this time, the block number of the packet is also checked, and when the packet with the old block number is mixed in, the process proceeds to step 913.

Step 912) If not received, the received packet is stored in the block buffer 321, and the packet management table 3223 indicates that the packet has been received.
Expect. (Step 913) When the packet having already been received or the packet having the old block number is included, it is discarded.

Step 914) The delivery start / end processing unit 3222 determines whether all the packets in the block are complete, whether the delivery start is received, or whether a timeout has occurred. Step 915) When one of the end conditions is satisfied in step 914, one block is passed to the application buffer 311. When the number of blocks is appropriately stored in the application buffer 311, the decoder 340 performs decoding and outputs to the external AV output device 301 and the database 302. In particular, the number of blocks is accumulated so that when outputting to the AV device 301, no blocks are lost and the output is not interrupted. The specific value depends on the size of the application buffer 311 and the allowable delay from input to output. The next block buffer is prepared, and the packet management table 3223 is reset (all packets are recorded as unreceived).

Here, the case of one block buffer has been described, but by preparing a plurality of block buffers, it is possible to cope with the next block reception which is continuously performed by the spare buffer. As a result, it is possible to prevent the process of passing the block to the AP buffer from becoming a bottleneck in the reception process.

Step 916) If the delivery end notification is received, the process proceeds to step 918, and if not received, the process proceeds to step 917. Step 917) Waiting for delivery start notification. If the delivery start notification is received or time-out occurs, step 907
Then, the process waits to receive the data packet of the next block. There may be a plurality of delivery start notifications, but if even one is received, the process proceeds to step 907.

Here, the delivery start notification is sent to the network 200.
If it is lost, the delivery of the next block will start immediately, but the next block can be received because it has already been prepared in step 915. If the delivery start notification has already been received before step 915, the process of step 917 is not performed.

Step 918) A response packet to the delivery start notification is returned to the server, and the reception ends. This process is used when the server 100 manages the success or failure of information delivery to each terminal 300 based on the response from the terminal 300.
There is also an implementation method that omits this response.

The present invention is not limited to the above embodiment, but various modifications and applications are possible within the scope of the claims.

[0076]

As described above, according to the continuous data delivery method and system of the present invention, the success or failure of data reception in packet units is recorded for continuous data such as information, thereby efficiently delivering duplicate data. Can be realized. In particular, since the execution of storing the received packet is determined only by checking the packet sequence number, no extra storage area or data copy between memories is required, which is efficient. As a result, continuous data can be delivered to a large number of terminals with high quality without error even when data loss occurs due to deterioration of network data transmission errors and temporary deterioration of reception performance at terminals.

Since the present invention does not perform re-sending, it has a particular application area when the transmission delay is large such as data delivery using satellites and ultra-long distance delivery over tens of thousands of kilometers.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention.

FIG. 2 is a principle configuration diagram of the present invention.

FIG. 3 is a system configuration diagram to which the present invention is applied.

FIG. 4 is a configuration diagram of a server of the present invention.

FIG. 5 is a configuration diagram of a delivery processing unit of the server of the present invention.

FIG. 6 is an example of a packet management table of the server of the present invention.

FIG. 7 is a block diagram of a terminal of the present invention.

FIG. 8 is a configuration diagram of a delivery processing unit of the terminal of the present invention.

FIG. 9 is an example of a packet management table of each terminal of the present invention.

FIG. 10 is a diagram for explaining a series of operations of continuous delivery according to the present invention.

FIG. 11 is a data configuration diagram of a data packet according to an embodiment of the present invention.

FIG. 12 is a data configuration diagram of a data packet according to an embodiment of the present invention.

FIG. 13 is a data configuration diagram of a delivery end notification packet according to an embodiment of the present invention.

FIG. 14 is a flowchart of a delivery procedure of the server according to the embodiment of this invention.

FIG. 15 is a flowchart of a delivery procedure of the terminal according to the embodiment of the present invention.

FIG. 16 is a conventional data delivery sequence to a plurality of terminals.

[Explanation of symbols]

100 server 106 camera / microphone 107 encoder 108 database 110 application management unit, application management unit 111 application buffer 112 application processing unit 120 delivery management unit, delivery processing unit 121 block buffer 122 delivery processing unit 130 communication control unit 140 duplicate delivery unit 150 Delivery completion notifying means 160 Delivery start notifying means 200 Communication network 300 Terminal 301 AV output device 302 Database 310 Application management unit, application management unit 311 Application buffer 312 Application processing unit 320 Delivery management unit 321 Block buffer 322 Delivery processing unit 330 Communication control unit 340 Decoder 341 Decode Buffer 350 Success / Failure Recording Means 60 response means 380 packet storing / discarding means 600 delivery start notification packet 601 terminal destination 602 packet type 603 delivery information 605 block size 606 block number 1221 packet delivery processing unit 1222 delivery start end processing unit 1223 packet management table 3221 packet delivery processing unit 3222 Delivery start / end processing unit 3223 Packet management table D00 Data packet D01 Terminal destination D02 Packet type D0B Block number D0P Packet number D03 User data F00 Delivery end notification packet F01 Terminal destination F02 Packet type

Claims (11)

[Claims] 1. A continuous data delivery method for delivering information continuously from a server to at least one terminal via a communication network, wherein the server encodes the information and a transmission rate of the communication network. The same block is transmitted to the terminal multiple times by utilizing the communication idle time caused by the difference in the data transmission, and when the first block delivery is missing, the data of the subsequent block is used for continuous data delivery. Method. 2. The server delivers continuous data to the terminal in block units assigned sequence numbers and packet units obtained by subdividing blocks, and in the terminal, the block units and packets delivered from the server. The unit data is received, based on the packet sequence number of the packet unit data, the success or failure of the data packet unit reception is recorded, and the record of the success or failure of the reception is collated with the sequence number of the packet just received. Then, if the received data packet has not been received before, it is stored in the block buffer, and if the received data packet has been received, it is discarded without being stored and the continuous data delivery method. 3. A plurality of block buffers are prepared in the server, the information from the outside is read in advance and stored in the plurality of block buffers, and there is no space for block delivery to the terminal. The continuous data delivery method according to claim 1 or 2, which is controlled as described above. 4. The terminal, when receiving a delivery start notification from the server, returns a response to the server only for the delivery start notification received at the very beginning of the data delivery. Continuous data delivery method. 5. A continuous data delivery system comprising a communication network, a server connected via the communication network, and at least one terminal to which data is continuously delivered from the server via the communication network. And a server and a terminal including application management means for managing delivery / reception of continuous data divided into block units, and delivery processing means for dividing the block into packets and performing delivery processing in packet units. A continuous data delivery system characterized by: 6. The delivery processing means of the server is a block unit in which continuous data is provided with a sequence,
6. The continuous data delivery system according to claim 5, further comprising: duplicate delivery means for delivering the blocks to the terminal in a duplicated manner in packet units. 7. The terminal refers to the success / failure recording means for recording the success / failure of reception in data packet units based on the sequence number, and refers to the success / failure recording means to determine whether the received data packet has not been previously received. 6. The continuous data delivery system according to claim 5, further comprising packet storing / discarding means for storing and discarding received data packets. 8. The delivery processing means of the server comprises a delivery start notifying means for delivering a delivery start notification packet to the terminal prior to the next block delivery every time the first data delivery and the block delivery are performed. 6. The continuous data delivery system according to claim 5, further comprising delivery completion notifying means for delivering a delivery completion notification packet to the terminal when the delivery is completed. 9. A response in which the delivery processing means of the terminal returns a response to the server only when the delivery start notification is the first notification of data delivery when the delivery start notification is received from the server. 8. A continuous data delivery system according to claims 5 and 7 including means. 10. The delivery processing means of the server has a plurality of block buffers, and includes first advance storage means for preceding reading from the application buffer of the application management means and for storing in the block buffer. The continuous data delivery system according to claim 5. 11. The application management means of the terminal includes a plurality of application buffers, and second advance storage means for storing the application management buffer in advance by reading from the block buffer of the delivery management means. The continuous data delivery system according to claim 5.