JPH0426261A - Multi-media communication equipment - Google Patents

Abstract

PURPOSE:To enable efficient multiplex communication by performing the optimum channel numbering to media delay, etc., by performing logical channel numbering in the order of the delay of plural connections. CONSTITUTION:A multiplex/division control part 100 is equipped with a media delay detection/compensation part 103 to detect and compensate the delay between respective media, a control part 104 controlling this entire multiplex division control part 100, a delay detection compensation part 105 to detect and compensate the delay between plural connections, a channel number control part 106 controlling the logical channel numbering after establishing the connection, and a division part 107 dividing by various kinds of media by a receiving information frame unit, and an output media selection part 108, etc. When performing multi-media multiplex transfer by the plural connections, the channel numbering is performed in the order of the delay between respective connections. Thus, efficient multiplex communication can be performed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention performs mutual communication with a partner communication device by combining a plurality of media information such as audio, various image information, or other coat information. The present invention relates to multimedia communication devices that constitute videophones, teleconference systems, etc.

[Prior Art] In recent years, practical use of communication services using 15DN circuits has begun, and AV (Audi.

The multimedia multiplexing frame structure for visual (Visual) services has been discussed by the CCITT (International Telegraph and Telephone Consultative Committee), and draft recommendation H.221 has been published.

In addition, the protocol procedures for AV service terminals using this recommendation H, 221 have been examined, and a draft recommendation H, 242 has been published.

According to the above recommendation H-221, 64Kbps ~ 1920Kb
The frame structure for the AV service in the PS channel is specified, and multimedia multiplex transfer is possible on multiple connections by using multiple connections. Signal definitions were made and the above Recommendation H, 242
The procedure is shown below.

FIG. 3 is an explanatory diagram showing a frame structure in a 64 Kbps channel.

In addition, Fig. 4 shows F A S (Frame Alig
nmentSignal) of 1 multi 7L/-mu (=1
This is a diagram showing the throat = 2 door sign between 67 frames) and 2
In the figure, R1, R2, and R3 indicate channel numbers at the time of multiple connections.

When using multiple connections, after frame synchronization and multi-frame synchronization are established during additional connections, the transfer delay for the initial connection is detected (hereinafter referred to as synchronization establishment) so that the delay between each connection can be compensated. ), sends and receives a synchronization establishment completion signal to the other party independently, and adds a channel number.

[Problem N to be solved by the invention] However, in the above conventional example, since channel numbers are sequentially assigned to each connection independently for transmission and reception starting from the connection for which synchronization has been established, the delay between each connection can be compensated. However, regarding the allocation of multiplexed media information for all channels, 1. In this case, the allocation is only performed in the order of channel numbers, and this allocation is extremely inefficient from the perspective of delay compensation.

For example, as shown in FIG. 5, assume that after synchronization is established for physical connections b1, B2, and B3 of BchX3 channels, logical channel numbers are assigned to each of them as B1, B2, and B3. And in this case, the delay between each connection is
For the initial connection b1, as shown in FIG.
b2=bl+t2, b3=bl-t3, It21
)1t31.

Also, audio 16KbpS and video 108.8Kbp
If connection delay is not considered, the media delay during s is assumed to be that the video is delayed by tAM from the audio, and even if media delay compensation tAN is performed, the video information will be further delayed by t2. It ends up. Here, t AM+ considering the connection delay t2
Although it is possible to compensate for the media delay of t2, this results in a very long communication delay as a whole, which has the drawback of making it impossible to have a conversation at a good tempo.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multimedia communication device that can effectively compensate for delays between media and can perform good mutual communication.

[Means for Solving the Problems] The present invention provides a multimedia communication device that establishes multiple connections with a partner communication device and mutually communicates multiplexed information of various media on these connections. , a detecting means for detecting a delay of each connection with respect to an initial connection, and a channel numbering means for comparing the delays of each connection and numbering channels in order of the delays.

According to the present invention, when performing multimedia multiplex transfer using a plurality of connections, efficient multiplex communication can be performed by assigning channel numbers in order of delay between each connection.

Furthermore, by considering media delay in addition to connection delay, channel numbering can be performed for optimal multiplexed communication.

This makes it possible to improve the quality of conversation services between remote locations.

Additionally, if the same media allocation is performed between both points, the media on each physical connection will also be the same, so if a failure occurs in one physical connection, recovery will not be possible using the other media. This can be done with minimal impact on

[Embodiment] FIG. 1 is a schematic block diagram of a multimedia communication device showing an embodiment of the present invention.

This communication device includes an audio input section 1 such as a microphone, an audio information output section 2 such as a speaker, and a video information input section 3 such as a camera.
, video information output unit 4 such as a monitor, and CCITT Recommendation Draft H, 221 frame for facsimile drawing, etc., TUD
An input unit 5 for code data information to be transferred as ()transparent user data) and an output unit 6 for the TUD.
and has.

This communication device also includes an input section 7 for controlling information and communication control information for controlling the entire device, an output section 8 for the control information, and an input section 8 for encoding, decoding, and input/output of audio information. an audio I/F (interface) control unit 9 that manages control; a video I/F control unit 10 that controls encoding, decoding, and input/output of video information; and input/output of code data information of the TUD. General control data i/
An f control unit 11 and a control information i/f control unit 12 that controls input and output of control information are provided.

Furthermore, this communication device includes an overall control unit 13 that controls the entire device, and a communication line 15-1.1 such as ISDN.
5-2... A line I/F control unit 14 that controls the interface with 15-n, multiplexing control for multiplexing various media inputs as transmission frames, and separation of reception frames into various media. and a multiplexing/demultiplexing control section 100 for controlling demultiplexing and outputting the multiplexed data.

FIG. 2 is a block diagram showing the internal configuration of the multiplexing/demultiplexing control section 100.

This multiplexing/demultiplexing control unit 100 includes an input media selection unit 101 that switches input media for transmission, and an input media selection unit 101 that changes the input media for transmission, and a transmission rate for each information frame that sends each media information to the communication line 15-1. a multiplexing unit 102 that multiplexes the media accordingly, a media delay detection/compensation unit 103 that detects and compensates for delays between media, and control units 104 and 1 that control the entire multiplexing/demultiplexing control unit 100. A connection delay detection and compensation unit 105 for detecting and compensating for inter-connection delays when multiple connections are established, and a channel number control unit 106 for controlling logical channel numbering after connection establishment are components for each received information frame. It has a separation unit 107 that separates each type of media, and an output media selection unit 108 that selects media to be output.

FIG. 3 is a schematic diagram showing the frame structure in a 64Kbps channel as indicated in draft recommendation H1221 by CCITT, and FIG. 4 is a schematic diagram showing FAS bit assignment within one multiframe as indicated in the draft recommendation. It is.

In the figure, R1, R2, and R3 represent logical channel numbers at the time of multiple connections.

FIG. 5 is a schematic diagram showing an example of multiplexing of each media information at the time of multiple connections in the two embodiments; audio information at 16 Kbps, video information at 108.8 Kbps, TDU information at 62.4 Kbps; An example of a multiplexed frame configuration when communicating is shown.

In the figure, logical channels B1, B2 . B1 for each B3
Audio 16Kbps on subchannels #1 and #2 of B], video information 108.8K on subchannels #4 to #8 and B2 of
bps, TUD information of 62.4 Kbps is assigned to B3.

Here, as shown in FIG. 7, H
A has a physical connection b1.A to the ISDN network. b
2. B1, B2 . B3 is assigned. At this time, it is assumed that the connection delay has a value of t2t3, as shown in FIG.

The present embodiment will be described in detail below based on the flowchart shown in FIG.

It is assumed that the Multimedia Communications HA establishes a bl call as an initial connection via the 15DN network, completes delay detection, and allocates logical channel B1 on the connection.

Here, in order to perform multimedia communication as shown in FIG. 5, additional connections B2 and B3 are established (S200).

Then, frame synchronization and multiframe synchronization are established asynchronously for each connection (5201).

Next, it waits until a delay with the initial connection b1 is detected (S202).

When the delay detection is completed and it is found that the synchronization between the connections can be compensated, a synchronization establishment completion signal is notified to the other party, and a logical channel number is added to the connection and notified (S203).

Here, physical connection b1. Logical channels B1, B2, and B3 are assigned to b2 and B3, respectively, and connection b2. The delay of b3 is
-As mentioned above, the values are +t2 and t3.

Then, it is checked whether the channel number is optimal (S204).

Here, as shown in FIG. 6, it can be seen that the connections are from b3 to bl-B2 in descending order of delay. Furthermore, considering the multiplexing method shown in Fig. 5 as necessary, the audio speed is 16 Kbps and the video speed is 108.8 Kbps.
If connection delay is not taken into account, the media delay during
Assuming that AIIIt3 and t AM > t 3, it is sufficient to allocate B1 = b 3 and B2 = b 1 and compensate for the media delay by t A) l - t 3 as best as possible. . Furthermore, since there is no harm in TDU information even if its real-time performance is lower than that of other media, B3=b2 is assigned.

Next, if the above conditions match the actual physical connection and logical channel number assignment, the process ends.

However, in this embodiment, since the optimal allocation is not made, B1=b3, B2=b 1 as described above.
, B3 = B2 (5205), and waits until all channel numbering is completed (S206, S
207) In this way, it is possible to perform optimal channel numbering that also takes into account media delay.

Note that the determination criteria in step 5204 may be based on consideration of only connection delay. If only the connection delay is considered, the same channel number will be assigned to both the sending and receiving sides. Furthermore, even when considering media delay, if the multiplexing method is the same for both transmission and reception, the same channel number will be assigned to both transmission and reception.

As a result, recovery processing for a failure that occurs in a certain physical connection during one communication can be performed efficiently because the failure can be detected on both the sending and receiving sides of the same medium.

In the embodiment described in L, channel renumbering for physical connections was mainly described from the perspective of connection delay and media delay, but in addition, for example, depending on the error rate on each connection, renumbering of channels such as TUD information It is also possible to add an f-method, such as allocating data to a connection with a low error rate.

[Effects of the Invention] As explained above, according to the present invention, since logical channel numbering is performed in order of delay of multiple connections,
Optimum channel numbering can be performed for media delays, etc., and efficient multiplexed communication can be performed.

Also, if the multiplexing of each media is the same for both sending and receiving,
Since the media on each physical connection are the same, even if a failure occurs in one physical connection, recovery can be performed with minimal impact on other media.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a multimedia communication device showing an embodiment of the present invention. FIG. 2 is a block diagram showing the internal configuration of the multiplexing/demultiplexing control section of the same embodiment. FIG. 3 is a schematic diagram showing a frame structure in a 64 Kbps channel indicated in draft recommendation HO221 by CCITT. FIG. 4 is a schematic diagram showing the FAS pit assignment within the 1 multiframe indicated in the above-mentioned draft recommendation H.221. FIG. 5 is a schematic diagram showing an example of multiplexing of media information when multiple connections are made in the same embodiment. FIG. 6 is a schematic diagram showing an example of the delay of each connection with respect to the initial connection in the same embodiment. FIG. 7 is a schematic diagram illustrating a state in which the multimedia communication device of the same embodiment is connected to an ISDN network. be. FIG. 8 is a flowchart illustrating the operation of the same embodiment. 1... Audio input section, 2... Audio information output section, 3... Video information input section 4... Video information output section, 5... TUD input section, 6... TUD output section, 7... Control information input unit, 8... Control information output unit, 9-12.14... i/f control unit, 13... Overall control unit, 15-1-15-n--. Communication line, 100... multiplexing/demultiplexing control unit. Patent Applicant Canon Co., Ltd. Agent Arata Nokubo Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 6Khρ5 nl) 1^ze) 624kbps 03.1lKbps Figure 6

Claims (2)

[Claims] (1) In a multimedia communication device that establishes multiple connections with a partner communication device and mutually communicates multiplexed information of various media on these connections, when the multiple connections are established, there is a delay in each connection with respect to the initial connection. 1. A multimedia communication device comprising: detection means for detecting; and channel numbering means for comparing delays of each connection and numbering channels in order of the delays. (2) The multimedia communication device according to claim (1), wherein the channel numbering means performs channel numbering that allows optimal multiplexing of a plurality of media based on connection delay and media delay.