JPH0879724A - Multi-media information transmission/reception system - Google Patents

Abstract

PURPOSE: To efficiently transmit picture and sound information provided with time attributes by dynamically assigning transmission bands to respective equipment. CONSTITUTION: A terminal equipment 30 transfers a timing information message to a cyclic transmission trigger part 38 in a reception data storage part 34 and starts data transmission in a transmission part 31 when relative time elapses. In the transmission part 31, data are taken out from a transmission data storage part 33 and the data are transmitted in response to a data transmission instruction from the trigger part 38. After first multi-media information is transmitted, the data transmission is started in the transmission part 31 at every prescribed time interval. Similarly, the terminals 20 and 40 extract the relative time and the time interval in the timing information message and transmit the data. In such a manner, since the transmission bands are dynamically assigned to the terminals, the terminals can transmit/receive the information provided with the time attributes. The terminal is informed of the required band of the transmission data beforehand, the required sufficient band is assigned by a center unit and the system operation of improved efficiency is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a real-time multimedia information transmitting / receiving system such as a video conference for handling packet switched traffic.

[0002]

2. Description of the Related Art A local area network (hereinafter referred to as LAN) is widely used in information communication systems in offices and the like.

FIG. 7 shows the configuration of a conventional packet switching type multimedia information transmitting / receiving system using such a LAN. In FIG. 7, 310 is a terminal device (A), 320 is a terminal device (B), 330 is a terminal device (C), and 340 is a terminal device (D). From the terminal device (A) 310 to the terminal device (D) 340, the transmission path 35
0 are connected to each other, and the terminal device (A) 31
From 0 to the terminal device (D) 340, the camera (A) 36
0, a camera (B) 370, a camera (C) 380, and a camera (D) 390 are connected. Terminal device (C) 3
Reference numeral 30 denotes a free channel detection unit 338 that determines whether there is data on the transmission path 350, a transmission data storage unit 333 that stores transmission data of multimedia information, and a reception data storage unit 334 that stores received multimedia information.
A transmission unit 331 for transmitting the multimedia information stored in the transmission data storage unit 333, a reception unit 332 for receiving the multimedia information from the transmission path 350, and a decoder unit 335 for decoding the received multimedia information. ,
An output unit 336 that displays the decoded multimedia information on the screen and outputs the sound, and an encoder unit 33 that encodes the multimedia information input from the camera (C) 380.
7 and 7.

The operation of the multimedia information transmitting / receiving system configured as described above will be described below. First, the multimedia information input from the camera (C) 380 is encoded by the encoder unit 337,
It is stored in the transmission data storage unit 333. When there is data in the transmission data storage unit 333, the free channel detection unit 338 determines whether there is data on the transmission path 350.
Here, when there is no data on the transmission path 350, the terminal device (C) 380 outputs the data stored in the transmission data storage unit 333 via the transmission unit 331. Since each terminal device has such a function,
For example, the terminal device (A) 310 and the terminal device (B) 320
Video conferencing will be realized between the two.

On the other hand, a method called circuit switching using the time division multiplexing method is also widely used (issued by Nikkei BP,
Nikkei Datacom 2 Time Division Multiplexer). This is to divide one line for each time and fixedly allocate the line.

[0006] Further, as an example of commercialization, St of the United States is used.
There is StarWorks from arlight. This is because the center device can transmit information having a time axis to each terminal device by allocating the band of the transmission path to the video information stored in the center device.

[0007]

However, in the above-described conventional packet switching configuration, as shown in FIG. 8, at time T1, the terminal device (A) 310 and the terminal device (D) 340 respectively receive the data 410. And data 41
Since transmission of 1 is started at the same time, a collision occurs on the transmission path. In the case where such transmission of multimedia information fails, it is necessary to perform a retransmission process and the like, and thus there is a problem in that transmission and reception of multimedia information having a time attribute is delayed.

Further, in the circuit switching configuration, in order to identify the assigned terminal, information including the identifier must be transmitted without fail, which is an overhead of the bandwidth of the transmission path.

Further, in the example of StarWorks, since the transmission is limited to the transmission from the center device and the transmission path cannot be assigned to the transmission from the terminal device, a video conference involving two-way communication is realized. It is not possible.

The present invention solves the above-mentioned conventional problems, and has a mechanism that does not cause a collision on a transmission path when handling multimedia information accompanied by real time such as a video conference, and the transmission. It is an object of the present invention to provide a multimedia information transmission / reception system capable of effectively using a band of a road.

[0011]

In order to achieve the above object, the present invention is a multimedia for connecting a plurality of terminal devices and a center device through a transmission line to realize mutual communication between the terminal device and the center device. In the information transmission / reception system, the center device includes means for calculating timing information for arbitrating the timing at which the center device and the terminal device send multimedia information, and means for notifying the terminal device of the timing information. The center device and the terminal device are provided with means for transmitting the multimedia information on the basis of the timing information.

Further, according to the present invention, the band required by the terminal device and / or the center device depending on the type of information to be transmitted,
The terminal device is provided with means for notifying the center device, and the center device is provided with means for notifying the terminal device, and the center device is adapted to calculate the timing information so as to secure the band required by the terminal device. .

[0013]

According to the present invention, with the above structure, the center device is
Since the terminal device connected via the transmission line in advance notifies the remote terminal device connected via the transmission line of the timing of transmitting the multimedia information, the multimedia information is determined at the timing determined by the terminal device side. When the center device or the plurality of terminal devices output the multimedia information by sending the, the output can be provided to the other terminal device without collision on the transmission path.

Further, according to the present invention, the band on the transmission line of the multimedia information is designated as necessary, and the center device calculates the timing information necessary for it, so that the band on the transmission line can be used effectively. it can.

[0015]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a multimedia information transmitting / receiving system according to the first embodiment of the present invention. In FIG. 1, 10 is a center device (A), 20 is a terminal device (B), 30 is a terminal device (C), 40 is a terminal device (D), and these are connected via a transmission line 50. . In the center device (A) 10, 11 is a transmission unit that realizes the output from the center device (A) 10, 42 is a usage state on the transmission path 50, and determines the transmission timing of data that has no time attribute. An empty channel detecting unit, 12 a receiving unit for receiving from the transmission path 50, 13 a transmission data storing unit for storing encoded data for transmission, 14 a receiving data storing unit for storing received data, 15 Is a decoder unit for decoding the received encoded multimedia information, 16 is an output unit for outputting the decoded multimedia information, and 17 is an input through a camera (A) 60 connected to capture the multimedia information. An encoder unit for encoding the stored multimedia information, 18 is a center unit (A) connected to a transmission line 50
10 and a timing arbitration unit that determines the transmission timing of each terminal device, and 19 is a synchronous transmission trigger unit that triggers transmission to the transmission line 50 at the transmission timing determined by the timing arbitration unit 18. Further, in the terminal device (C) 30, 31 is a transmission unit that realizes the output from the terminal device (C) 30, 45 is an empty channel detection unit that determines the transmission timing of data having no time attribute, 3
2 is a receiving unit for receiving from the transmission path 50, 33 is a transmission data storage unit for storing encoded data for transmission,
34 is a received data storage unit for storing received data, and 3
5 is a decoder unit for decoding the received encoded multimedia information, 36 is an output unit for outputting the decoded multimedia information, and 37 is a camera (C) 80 connected to capture the multimedia information. An encoder unit for encoding multimedia information input through
8 is a transmission path 50 depending on the transmission timing of the terminal device (C) 30 determined and transmitted by the center device (A) 10.
It is a synchronous transmission trigger unit that applies a trigger at the time of transmission to.
The terminal device (B) 20 and the terminal device (D) 40 also have the same configuration as the terminal device (C) 30.

In FIG. 2, the horizontal axis represents time and the vertical axis represents the device on the transmission side, and shows the relationship between the time and the transmission terminal for the data on the transmission path of the multimedia information transmission / reception system. The data 101 on the transmission path is transmitted from the terminal device (C) 30 at time T1, and occupies the transmission path for Tex time.

FIG. 3 shows a message transmitted from each terminal device to the center device. Before the terminal starts transmitting multimedia information, it transmits a start message (a) to the center device. Control message 15 indicating that the start message (a) is a start or end message
0, a terminal identifier 151 that identifies a terminal that transmits multimedia information, and a start identifier 152 that indicates a start message. The end message (b) is composed of a control code 160 indicating a start or end message, a terminal identifier 161 identifying a terminal transmitting multimedia information, and an end identifier 162 indicating a end message. To be done.
(C) is a timing information message transmitted from the center device to each terminal device. The timing information message (c) includes a control code 170 indicating that it is a timing information message and terminal identifiers 171, 173, 1
75 and the transmission timings of the terminal devices indicated by these terminal identifiers, relative time 172 from the reference time, 1
74, 176 and a time interval 177.

The operation of the multimedia information transmitting / receiving system of the first embodiment configured as above will be described below. First, the terminal device (B) 20,
(C) 30 and (D) 40 request the center device (A) 10 to acquire the right to provide the service, and then the center device (A) 10 sends the timing information, which is the transmission timing of the terminal device. Arbitration and terminal device (B)
The flow of processing until 20, (C) 30, and (D) 40 receive timing information will be described. In FIG.
When there is an input from the camera (C) 80 connected to the terminal device (C) 30 to the transmission data storage unit 33 through the encoder unit 37, and the free channel detection unit 45 detects the free space of the transmission path 50, it is shown in FIG. So that the terminal device (C)
The data 101 of the start message (a) in FIG.
At, the transmission is performed to the center device (A) 10. Similarly, the terminal devices (D) 40 and (B) 20
Transmits data 100 and data 102 to the center device (A) 10. The center device (A) 10 has a time interval Tbet that can be transmitted by the terminal device based on the number of the terminal devices that want to provide the service, and a relative time from the reference time Ts of the center device (A) 10 and each terminal device. Ta, Tb, Tc, Td and Teno are calculated by the timing arbitration unit 18 in FIG. Here, the reference time Ts is the time when each terminal device finishes receiving the timing information message. A value obtained by subtracting Tbet from Teno is used as a band that is not assigned to each terminal device, and is a band for exchanging information that does not have a time axis, such as the end message (b). Center device (A) 10
Is the timing information message (c) shown in FIG. 3 when the free channel detection unit 42 detects the free space of the transmission path 50.
2 is used to notify the terminal device (B) 20, the terminal device (C) 30, and the terminal device (D) 40 of the timing information data 103 of FIG.

The terminal device (C) 30 stores the received timing information message (c) in the received data storage section 34. When the reception data storage unit 34 refers to the control code 170 of the timing information message (c) of FIG. 3 and determines that the reception data is the timing information message (c), the relative time 1 following its own terminal identifier 173.
74 and the time interval 177 to extract the synchronous transmission trigger unit 38.
Transfer to. In the synchronous transmission trigger unit 38, when the relative time 174 has elapsed, the transmission unit 31 is activated for data transmission. In the transmission unit 31, the transmission data storage unit 33
The data 106 is transmitted from the synchronous transmission trigger unit 38 when the data transmission command is extracted from the synchronous transmission trigger unit 38. Interval 177 after sending the first multimedia information
That is, in FIG. 2, the transmission unit 31 is activated for data transmission at every Tbet time.

Similarly, the terminal device (B) 20 and the terminal device (D) 40 have the terminal identifier 171 and the terminal identifier 175 in the timing information message (c) of FIG.
Then, the relative time 172 and the relative time 176 and the time interval 177 are extracted, and the data 105 and the data 107 are transmitted. After that, the center terminal (A) 10, the terminal device (B) 20, the terminal device (C) 30, and the terminal device (D) 40 have the data 10 based on the time interval 177.
8, 109, 110, 111 are transmitted. This is because, also in the center device (A) 10, the timing arbitration unit 18 notifies the synchronous transmission trigger unit 19 of the relative time and the time interval.

Next, the operation when the terminal device (D) 40 terminates the transmission in such four-way communication will be described. When the terminal device (D) 40 ends the transmission,
After detecting the vacancy of the transmission line 50, the end message (b) of FIG. 3 indicated by the data 112 of FIG. 2 is transmitted to the center device (A).
Send to 10. Upon receiving the end message (b), the center device (A) 10 causes the timing arbitration unit 18 to
Relative times Ta ', Tb', Tc 'and Ten in FIG.
o ′ and the time interval Tbet ′ are calculated. The center device (A) 10 uses the timing information message (c) of FIG.
2 is used to notify the terminal device (B) and the terminal device (C) of the updated relative time and absolute time in the data 113 of FIG. The center device (A) 10, the terminal device (B) 20, and the terminal device (C) 30 use the updated relative time and time interval to set the data 11 at the determined timing.
4, 115, 116, 117, 118, and 119 are transmitted.

(Second Embodiment) Next, a second embodiment of the present invention will be described. FIG. 4 shows a schematic configuration of a multimedia information transmitting / receiving system according to the second embodiment of the present invention. In FIG. 4, 10 is a center device (A), 1
1 is a transmission unit, 12 is a reception unit, 13 is a transmission data storage unit,
14 is a received data storage unit, 15 is a decoder unit, 16 is an output unit, 17 is an encoder unit, 18 is a timing arbitration unit,
19 is a synchronous transmission trigger unit, 42 is an empty channel detection unit,
20 is a terminal device (B), 30 is a terminal device (C), 31 is a transmitter, 32 is a receiver, 33 is a transmission data storage, 34
Is a received data storage unit, 35 is a decoder unit, 36 is an output unit, 37 is an encoder unit, 38 is a synchronous transmission trigger unit, 4
5 is an empty channel detector, 40 is a terminal device (D), 50
Is a transmission line, 60 is a camera (A), 70 is a camera (B),
Reference numeral 80 is a camera (C), 90 is a camera (D), and the above is the same as the configuration of FIG. The difference from the configuration of FIG. 1 is that the center device (A) 10 has an encoding control unit 41 and a decoding control unit 43, and terminal devices (B) 20 and (C) 3.
0, (D) 40 is provided with an encoding control unit 44 and a decoding control unit 46.

FIG. 5 shows the relationship between the time and the transmitting terminal for the data on the transmission path of the multimedia information transmitting / receiving system, with the horizontal axis representing the time and the vertical axis representing the transmitting side device.

FIG. 6 shows the structure of a message from the terminal device in this embodiment. In FIG. 6, the start message (aa) is a control code 150 and a terminal identifier 151.
And a start identifier 152, and the above configuration is similar to that of FIG. The difference from the configuration of FIG. 3 is that a required band 153 is provided in the start message. The change message (ab) includes a start message, a control code 155 indicating that the message is a change message, a terminal identifier 156 for identifying a terminal that transmits multimedia information,
A change identifier 157 indicating that the message is a change message,
It is composed of a required band 158 which indicates a required band.
The end message (b) includes a control code 160, a terminal identifier 161, and a start identifier 163. The above configuration is similar to that of FIG. The timing information message (c) includes the control code 170 and the terminal identifier 1
71, 173, 175 and relative time 172, 174, 1
76 and a time interval 177. The above configuration is shown in FIG.
The configuration is the same as that of.

The operation of the multimedia information transmitting / receiving system of the second embodiment configured as described above will be described below. First, the terminal device (B) 20 makes a request to the center device (A) 10 to acquire the right to provide the service, and then the timing information that is the transmission timing of the terminal device (B) 20 is sent to the terminal device (B) 20. (B) 20
The flow of processing up to the reception by will be described. In FIG. 4, the encoding control unit 44 of the terminal device (B) 20 controls the encoder unit 37 to operate the spatial resolution and the temporal resolution of the multimedia information, and notifies the synchronous transmission trigger unit 38 of the situation. To do. When there is an input from the camera (B) 70 connected to the terminal device (B) 20 to the transmission data storage unit 33 through the encoder unit 37, the terminal device (B) 20 causes the empty channel detection unit 45 to open the transmission path 50. 6 is detected, as shown in FIG. 5, the start message (aa) shown in FIG.
Data 202 is transmitted to the center device (A) 10. In the required bandwidth 153 of the start message (aa), the synchronous transmission trigger unit 38 determines the required bandwidth of the multimedia information on the transmission path 50, determines a value, and inserts the value. Similarly, the terminal device (C) 30 and the terminal device (D) 40 also transmit the data 201 and 200 to the center device (A) 10. The center device (A) 10 transmits a time interval Tbe that can be transmitted by the terminal device from the required band requested by the terminal device that wants to provide the service.
t, relative times Ta, Tb, Tc, Td, and Teno from the reference time Ts of the center apparatus (A) 10 and each terminal apparatus.
And are calculated in the timing arbitration unit 18 of FIG.
Here, the reference time Ts is the time when each terminal device finishes receiving the timing information message. Also, Teno
The value obtained by subtracting Tbet from is used as a band that is not allocated to each terminal device, and as a band for exchanging information that does not have a time axis such as an end message. The center device (A) 10 uses the timing information message (c) shown in FIG. 30 and the terminal device (D) 40 are notified of the timing information data 203 of FIG.

The terminal device (B) 20 stores the received timing information message (c) in the received data storage section 34. When the received data storage unit 34 refers to the control code 170 of the timing information message (c) of FIG. 6 and determines that the received data is the timing information message (c), the relative time 1 following its own terminal identifier 171
72 and the time interval 177 to extract the synchronous transmission trigger unit 38.
Transfer to. When the relative time 172 has elapsed in the synchronous transmission trigger unit 38, the transmission unit 31 is activated to start data transmission. In the transmission unit 31, the transmission data storage unit 33
The data 205 is transmitted from the synchronous transmission trigger unit 38 upon receiving the data transmission command from the synchronous transmission trigger unit 38. Interval 177 after sending the first multimedia information
The data transmission is activated in the transmission unit 31 every time. The center device (A) 10 that has received the data is controlled by the decoding control unit 43 to match the band changed by the terminal device (B) 20, and is decoded by the decoder unit 15.

Similarly, the terminal device (C) 30 and the terminal device (D) 40 have the terminal identifier 173 and the terminal identifier 175 in the timing information message (c) of FIG.
Then, the relative time 174 and the relative time 176 and the time interval 177 are extracted and the data 206 and the data 207 are transmitted. After that, the center terminal (A) 10, the terminal device (B) 20, the terminal device (C) 30, and the terminal device (D) 40 have the data 20 based on the time interval 177.
8, 209, 210 and 211 are transmitted. This is because also in the center device (A) 10, the timing arbitration unit 18 notifies the synchronous transmission trigger unit 19 of the relative time and the time interval.

Next, the operation when the terminal device (C) 30 terminates the transmission in such four-way communication will be described. When the terminal device (C) 30 finishes the transmission,
The end message (b) of FIG. 6 indicated by the data 212 of FIG.
After detecting the vacancy of the transmission line 50, the center device (A)
Send to 10. Then, the terminal device (D) 40 shown in the data 213 of FIG. 5 in order to change the transmission band.
Of the change message (ab) is transmitted to the center apparatus (A) 10 after detecting the vacancy of the transmission path 50, the center apparatus (A) 10 receiving the end message (b) and the change message (ab) changes the timing. In the arbitration unit 18, the relative times Ta ′, Tb ′, Tc ′ and Te of FIG.
No 'and the time interval Tbet' are calculated. The center device (A) 10 uses the timing information message (c) of FIG.
5 is used to notify the terminal device (B) 20 and the terminal device (D) 40 of the updated relative time and time interval in the data 214 of FIG. The center device (A) 10, the terminal device (B) 20, and the terminal device (D) 40 use the updated relative time and time interval to determine the data 215, 216, 217, 218, 219 at the determined timing. 220
To send.

As described above, according to the second embodiment, the band to be used is changed in accordance with the multimedia information transmitted by the terminal device and the center device is notified, so that the timing information corresponding to the changed bandwidth can be obtained. To communicate with,
The band on the transmission path can be effectively used. Such a band change may be set by the center device itself and notified to the terminal device, or only one of the terminal device and the center device may be configured.

In the first and second embodiments, the transmission time of the terminal device is specified by the center device as relative time and time interval, but it can be specified as absolute time and time interval. .

Further, in the first and second embodiments, in order to improve the accuracy of the timing of transmission by each terminal device depending on the accuracy of the clock of each terminal device, the end message and the change message are sent to the terminal device. The timing information message can be transmitted from the center device even if it is not transmitted from the center device.

Furthermore, in the first and second embodiments described above, a plurality of center devices can determine the timing information in cooperation with each other.

[0033]

As described above, according to the present invention, when the information having the time attribute is transmitted and received between the devices, the transmission band is dynamically allocated to each device. Each terminal device can send and receive. Further, by notifying the terminal device of the required band of the transmission data in advance, the center device can allocate the necessary and sufficient band, and it is possible to provide a system in which the resource can be operated without waste.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a multimedia information transmitting / receiving system according to a first embodiment of the present invention.

FIG. 2 is a timing chart of data transmission from each terminal to a transmission line in the first embodiment of the present invention.

3A is a format diagram showing a data structure of a start message in the first embodiment. FIG. 3B is a format diagram showing a data structure of an end message in the first embodiment. FIG. 3C is a timing in the first embodiment. Format diagram showing the data structure of information

FIG. 4 is a block diagram showing a configuration of a multimedia information transmitting / receiving system according to a second embodiment of the present invention.

FIG. 5 is a timing chart of data transmission from each terminal to a transmission line in the second embodiment of the present invention.

6 (aa) is a format diagram showing a data structure of a start message in the second embodiment. (Ab) is a format diagram showing a data structure of a change message in the second embodiment. (B) Ends in the second embodiment. Format diagram showing the data structure of the message (c) Format diagram showing the data structure of the timing information in the second embodiment

FIG. 7 is a block diagram showing the configuration of a conventional information transmitting / receiving system.

FIG. 8 is a timing chart of data transmission from each terminal to a transmission line in a conventional information transmission / reception system.

[Explanation of symbols]

 10 Center Device (A) 11 Transmitter 12 Receiver 13 Transmitted Data Storage 14 Received Data Storage 15 Decoder 16 Output 16 Encoder 18 Timing Arbitration 19 Synchronous Transmission Trigger 20 Terminal Device (B) 30 Terminal ( C) 31 transmission unit 32 reception unit 33 transmission data storage unit 34 reception data storage unit 35 decoder unit 36 output unit 37 encoder unit 38 synchronous transmission trigger unit 40 terminal device (D) 41, 44 encoding control unit 42, 45 empty channel Detection unit 43, 46 Decoding control unit 50 Transmission path 60 Camera (A) 70 Camera (B) 80 Camera (C) 90 Camera (D)

Claims (2)

[Claims] 1. A multimedia information transmission / reception system in which a plurality of terminal devices and a center device are connected by a transmission line to realize mutual communication between the terminal device and the center device, wherein the center device is a center device and a terminal device. Includes means for calculating timing information for arbitrating the timing of transmitting multimedia information, and means for notifying the terminal device of the timing information, and the center device and the terminal device transmit the multimedia information. At this time, a multimedia information transmitting / receiving system including means for transmitting based on the timing information. 2. The terminal device and / or the center device,
The terminal device has means for notifying the center device in the case of a terminal device and the terminal device in the case of a center device, and the band required by the center device or itself by the center device. The timing information is calculated so as to ensure
The described multimedia information transmission / reception system.