JP3222591B2 - Multimedia communication terminal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multimedia communication terminal for multiplexing a data signal such as telewriting data and a voice signal for communication, and more particularly to a multimedia communication terminal capable of simplifying a data communication protocol. .

[0002]

2. Description of the Related Art Hitherto, multimedia communication terminals for communicating multimedia data such as text data, handwritten input data (telewriting data), still images, and moving images, in addition to audio signals, have been widely used. The multimedia communication terminal device is used for, for example, a videophone or a video conference system. Conventional multimedia communication terminals of this type include, for example, Japanese Patent Laid-Open No. 4-26.
No. 261, one or more communication channels can be established with a partner device, and multiplexed information of various media can be mutually communicated on this communication channel. The information multiplexing communication system used at this time is CCITT (International Telegraph and Telephone Consultative Committee) recommendation H.264. 221
AGC (Audio Graphic Conferenc)
e) Recommendation work on a data communication system called a protocol is currently underway. This Recommendation H. H.221 specifies a method of multiplexing and communicating a voice signal and a data signal on an I channel (a first channel when a plurality of B channels are used) . The AGC recommendation states that data
In the communication of the issue, recommendation H. It is defined that the upper layer of the multiplex processing unit that performs multiplexing according to H.221 is the data link layer of the OSI reference model.

The data link layer is defined as the second layer of the OSI reference model. The lower first layer is a physical layer, the upper third layer is a network layer, the fourth layer is a transport layer, and the fifth layer. Is defined as a session layer, the sixth layer is defined as a presentation layer, and the seventh layer is defined as an application layer. Here, the data link layer has a function of detecting and correcting a bit error occurring on a transmission path between systems.

[0004]

However, in such a conventional multimedia communication terminal device, a function of detecting an error in multiplexed data is also provided in a multiplex processing unit positioned below the data link layer. Therefore, there is a waste that the error detection of the data signal is performed redundantly in the multiplex processing unit (recommendation H.221) and the data link layer of the OSI reference model.

Accordingly, the present invention omits error detection performed in the data link layer of the OSI reference model, and proposes error detection of a data signal on a communication line according to Recommendation H.264. An object of the present invention is to provide a multimedia communication terminal device that can simplify a data communication protocol by avoiding duplication of error detection by the multiplex processing unit and the data link layer by executing only the multiplex processing unit conforming to H.221.

Further, by positioning the multiple processing unit in the lower transport layer, skipping the data link layer does not perform error detection of the data, omitting the data link layer and the network layer of the OSI reference model, the data communication An object of the present invention is to provide a multimedia communication terminal device that simplifies a protocol and reduces the amount of communication data.

Next, the error detection of the multiplex processing unit is uniformly performed without discriminating the voice signal and the data signal, and the correction function is left to the data link layer or the transport layer. Here, the allowable value of the error occurrence probability is different between the voice signal and the data signal, and the allowable value is more strict for the data signal than for the voice signal. For this reason, the detected errors include errors in audio signals that do not require correction processing. Therefore, if the line quality is good, there is room to perform correction processing on all detected errors, but if the line quality is bad, correcting all errors will make the protocol complicated. As a result, there is a problem that the loss increases both in terms of time and economy.

Accordingly, the present invention provides a method for transmitting a data signal to a partner having a high error occurrence probability detected by a multiplex processing unit .
Error correction is not affected by error detection caused by audio signals.
It is an object of the present invention to provide a multimedia communication terminal device that switches to a new mode (conventional mode) . Also ,
If the one Dan error probability and continuously communicate the following error probability predetermined value monitors communication with the other party it is determined that high, it is determined that the line quality is improved to release the error detection of the data signal only Accordingly, it is an object of the present invention to provide a multimedia communication terminal device that automatically returns to a uniform error detection of a voice signal and a data signal by only a multiplex processing unit.

[0009]

According to the first aspect of the present invention,
To achieve the above object, a multiplexing unit having a multiplexing function for multiplexing a voice signal and a data signal on one communication channel and a function of detecting an error of the multiplexed data;
Wherein corresponding to the reference model and the data link layer with error detection and correction functions preceded Kide data signal, in the multimedia communication terminal apparatus positioned the multiplexing processing unit to the lower data link layer, the The data error detection function of the data link layer is stopped, and an error of the multiplexed data is detected only by the multiplex processing unit.

According to a second aspect of the present invention, in the multimedia communication terminal device according to the first aspect, the data link layer and the network layer of the OSI reference model are omitted in the communication of the data signal. The multi-processing unit is positioned below the transport layer of the OSI reference model. According to a third aspect of the present invention, in the multimedia communication terminal device according to the first or second aspect, the error occurrence probability of the multiplexed data detected by the multiplex processing unit is equal to or more than a predetermined value. registration means for registering a communication partner becomes, the multiplex processing unit present in another layer, data in the multiplexed data
Error detecting means for performing error detection only on a signal, and communicating with a partner registered in the registering means.
The error detection means only applies to the data signal.
Error detection is performed .

According to a fourth aspect of the present invention, there is provided a multimedia communication terminal according to the third aspect, wherein an error detected by a multiplex processing unit in communication with a registered partner is achieved. Counting means for counting the number of continuous communications in which the probability of occurrence has fallen below a predetermined value, and if the number of continuous communications exceeds a set value, stop error detection by the error detection means and return to error detection by the multiplex processing unit alone And return means for performing the operation. Also,
According to a fifth aspect of the present invention, an audio signal is transmitted to one communication channel.
Multiplexing function for multiplexing data signals and data signals
Multiple processing unit with data error detection function and OSI reference
Individual error detection for the data signal corresponding to the model
And a data link layer having a correction function.
The multi-processing unit is positioned below the data link layer.
In a multimedia communication terminal device, the data link
Stop the layer data error detection function and only the multiplex processing unit
Detecting errors in multiplexed data by
You. The invention according to claim 6 is the invention according to claim 1 or claim
The multimedia communication terminal device according to item 5, wherein
OSI reference model data used in data communication protocols
Data link layer and network layer are omitted and multiple processing unit
OSI reference model used in data communication protocol
Characterized by being positioned below the transport layer of
You. Further, the invention described in claim 7 is the invention according to claim 1 or claim
The multimedia according to claim 2 or claim 5 or claim 6.
In the communication terminal device, the
The error occurrence probability of the multiplexed data
Registration means for registering a contact, and communication with the registered
Error detection of the data signal in the multiplexed data
Error detecting means other than the multiplex processing unit for performing
It is characterized by the following. Further, the invention described in claim 8 is
Item 7. The multimedia communication terminal device according to Item 7,
Error detected by the multiplex processing unit in communication with the specified partner
The number of consecutive communications in which the probability of occurrence of
Counting means and the number of consecutive times exceeds the set value.
Error detection means other than the multiplex processing unit
Stop the output to return to the error detection by only the multiplexing processing unit
And return means.

[0012]

According to the first or fifth aspect of the present invention, the data error detection function of the data link layer is stopped, and only the multiplex processing unit detects an error in the multiplexed data, so that the multiplexed data is detected. The data communication protocol is simplified by avoiding duplication of error detection between the processing unit and the data link layer.

Further, claim 2 or請 having the above structure
In the invention according to claim 6, the data link layer and the network layer of the OSI reference model are omitted, and the multiplex processing unit is positioned below the transport layer of the OSI reference model, thereby simplifying the data communication protocol and communicating. Reduce data volume. In the third or seventh aspect of the present invention having the above configuration, when the error occurrence probability of the multiplexed data detected by the multiplex processing unit is equal to or greater than a predetermined value, the communication partner is registered in the registration unit. When registering and communicating with the registered partner next time, only the data signal of the multiplexed data is separate from the multiplex processing unit.
Also Oite error detection means by performing error detection, with respect to the first aspect of the invention, to reduce the correction number of the data signal.

[0014] Further, according to the fourth aspect or the contract having the above configuration ,
In the invention according to claim 8, when communicating with a registered partner, the number of continuous communications in which the probability of occurrence of an error detected by the multiplex processing unit has become equal to or less than a predetermined value is counted by the counting means. When the number of consecutive times exceeds the set value, the recovery means stops error detection by the error detection means and returns to error detection by only the multiplex processing unit, thereby executing error detection and correction adapted to communication quality. I do.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
FIG. 2 shows a first example of the multimedia communication terminal device according to the present invention .
It is a block diagram which shows an Example . A multimedia communication terminal device for transmitting and receiving a voice call and text data, handwritten input data, a still image, and a moving image will be described as an example of the device of the present embodiment.

First, the configuration will be described. In the figure, 10
0 is a telewriting communication terminal device of the present embodiment,
The system control unit 11 includes a ROM (Read Only Memory) 1
Each part of the apparatus is controlled according to the program in 2. R
The OM 12 stores a control program and the like for the present apparatus. Recommendation H.221, which defines a communication procedure using H.221. A communication protocol conforming to H.242 is also stored here. RAM (Random Access Memory) 13
Stores various data necessary for controlling the apparatus. The image memory 14 temporarily stores image data read by the scanner 15 of the present apparatus or stores image data received from a partner terminal. The communication control unit 16 is connected to a handset (so-called handset) 17, a microphone 18, a speaker 19, and the like, and performs a voice codec for performing A / D conversion of a voice signal. 221 multiplexing / demultiplexing control unit for various media data.

The encoding / decoding unit 20 includes a moving image codec and a still image codec, and encodes and decodes moving image data and still image data. Operation unit 21
Is provided with a numeric keypad for the operator to input a destination telephone number, various operation keys for enlarging / reducing the display content of the display 22, and instructing editing. The scanner 15
Using a CCD (Charge Coupled Device), an original is read for each line and output as image data.

The drawing input unit 23 is composed of a tablet and its control unit, detects a portion touched by a dedicated pen tip, and takes in the position information. Display unit 2
2 includes a display (display unit) composed of a CRT or an LCD, and a display control unit for controlling the display.
The display control unit performs screen control such as enlargement / reduction of display contents and multi-window. Note that the display area of the display unit 22 and the input area (tablet) of the drawing input unit 21 correspond to each other, and handwritten information input through the drawing input unit 21 is displayed on the display 22 in real time. The television camera 24 can input an image of a person of the operator and the like, and the input image can be displayed on the display 22. Note that the telewriting communication terminal device 100 of the present embodiment connects each of the above-described components by a system bus 25 and outputs the IS through a communication control unit 16.
It shall be connected to a digital line L such as a DN line or a dedicated line.

FIG. 1 is a configuration diagram showing a hierarchical structure of a data communication protocol in this embodiment . In FIG. 1, a telewriting application layer 31 is an application (application) layer defined as the uppermost layer of the OSI reference model. In this embodiment, the telewriting application layer 31 handles handwritten information input from the drawing input unit 23 shown in FIG. Shall be. The session layer 32 is the fifth layer of the OSI reference model.
A layer defined as a layer. In accordance with H.225, a method of sending information required by the process (for example, half-duplex or full-duplex management, transmission right management, and the like), synchronization between processes, and management of resynchronization are performed.

The transport layer 33 is a layer defined as the fourth layer of the OSI reference model. 2
In accordance with 24, for example, the occurrence of a transmission error is detected and corrected to ensure reliable data transfer. The network layer 34 is a layer defined as the third layer of the OSI reference model, and establishes a communication path with a partner. The data link layer 35 is a layer defined as the second layer of the OSI reference model, and detects and corrects a bit error occurring on a communication path with a partner.

H. The 221 processing unit 36 is a multiplex processing unit according to the present invention, and has a multiplexing function of multiplexing a voice signal and a data signal (telewriting data in this embodiment) on one communication channel, and an error of the multiplexed data. Has a detection function. For this, H.I. The audio processing 37 and the H.221 The telewriting application 31 via the 242 execution unit 38 is connected. The audio processing unit 37 includes an audio codec, and processes audio signals handled by the handset 17, the microphone 18, the speaker 19, and the like in FIG. H. The 242 execution unit 38
H. 221 implements a higher-level protocol for executing the communication procedure of the processing unit 36.

Here, the configuration of this embodiment will be described. Recommendation H. In H.221, H.221 The upper layer of the H.221 processing unit 36 is the data link layer 3 of the OSI reference model.
5 is recommended. In this case, H. The 221 processing unit and the data link layer 35 must perform data signal error detection redundantly. Therefore, in this embodiment, the hierarchical structure is shown as a solid line portion in FIG.
The data link layer 35 of the OSI reference model
Omitting the network layer 34, 221 processing unit 3
6 is positioned below the transport layer 33. This
In the case of Error detected by the H.221 processing unit 36
Is corrected by the transport layer 33
become.

[0023]

Next, the operation will be described. Apparatus 1 of the present embodiment
00 is capable of various media data communication as described above, but here, voice and handwritten input data are stored in one B
The case of multiplexing by channels will be described .

First, when a call is connected using the D channel, an in-channel procedure starts. And Recommendation H. In accordance with H.242, a capability information exchange sequence is performed to switch to a desired communication mode. In this embodiment, the mode is set to 56 kbi.
t / s audio, 6.4 kbit / s MLP (Mult
i Layer Protocol data). By setting such a communication mode, voice communication and communication of handwritten input data can be performed in one B channel.

The telewriting application 31 shown in FIG. 1 recognizes the telewriting data based on the drawing input position information received from the drawing input unit 23 in FIG. Input position information to session layer 32
Pass to. In the session layer 32, the recommendation X. By executing a protocol conforming to H.225, communication management conditions such as full-duplex communication or half-duplex communication depending on a token are set between the terminal and the other terminal according to an instruction from the telewriting application 31. In the transport layer 33, the recommendation X. H.224 protocol is executed, and flow control and H.264 are performed. The data retransmission process is performed when an error detected by the H.221 processing unit 36 occurs. In the OSI, a network layer 34 and a data link layer 35 exist as lower layers of the transport layer 33. However, in the communication of the present embodiment, these layers 3 except for the error detection function are used.
The functions of 4, 35 are integrated in the transport layer 32. Therefore, communication is performed in the unique mode conforming to the transport class 1 .

An H.264 signal which exists in a lower layer of the transport layer 33 and multiplexes an audio signal and telewriting data. The H.221 processing unit 33 includes: H. 221 for executing a communication procedure using H.221 242 execution unit 38 is connected. The 242 execution unit 38 is connected to the telewriting application 31. H. 2
An audio processing unit 37 is connected to the 21 processing unit 36, and the audio processing unit 37 processes an audio signal such as voice.

FIG. 3 is a communication flowchart showing an error correction sequence according to the data communication protocol of FIG. Upon receiving the data transmission request from the session layer 32, the transport protocol execution unit (transport layer 33) of the transmitting terminal converts the telewriting data into DT TPDU for each data unit corresponding to the transmission sequence number.
(1), DT TPDU (2),. 221 to the processing unit 36. Note that DT is Data, and TPDU is
Abbreviation for Transport Protocol Data Unit. H. 22
The one processing unit multiplexes the received data unit with audio data. Here, the multiplexed data is transmitted to the receiving terminal. H. of the receiving terminal 221 processing unit 36
Separates the received multiplexed data into telewriting data (DT TPDU) and audio data, and sends the telewriting data to a transport protocol execution unit of its own terminal. The transport protocol execution unit sends an instruction signal for displaying an image on the display 22 of the terminal based on the telewriting data. Thus, the common telewriting data can be displayed on the screen for both the transmitting terminal and the receiving terminal.

At this time, H. The 221 processing unit 36 uses a 4-bit cyclic redundancy detection (CRC4) procedure as error detection. The block size of CRC4 is B
160 octets for a channel, calculated 50 times per second. If an error is detected in this CRC4, for example, if an error is detected for multiplexed data including DT TPDU (2), The 221 processing unit 36 notifies the transport protocol execution unit that an error has occurred. Upon receiving the notification, the transport protocol execution unit issues a retransmission instruction for this multiplexed data to H.264. 221 to the processing unit 36.
H. The H.221 processing unit 36 is a FAS (Frame Asynchronous
Signal), the fourth bit (E bit) of the odd-numbered frame is set to “1” and transmitted to the transmission terminal. If the E bit of the received FAS is “1”, the transmitting terminal notifies the transport protocol execution unit that an error has occurred. Upon receiving this notification, the transport protocol execution unit retransmits the previously transmitted data unit DT TPDU (2).

In this way, the H.264 of the receiving terminal is used. The 221 processing unit 36 and the transport protocol execution unit execute error detection and correction, respectively. Since it is not necessary to correct the audio error, H.264 is used. The 221 processing unit 36 does not notify the audio processing unit 37 of an error. Thus, in the present embodiment, the data error
Jump over the data link layer 35 that does not perform detection
H. is provided below the transport layer 33. 221 processing unit 36
The data communication protocol.
Omit the link layer 35 and the network layer 34
Protocol can be simplified. Also, Ray
Since the header part of the data is reduced by omitting the
Data can be reduced, and conversely, if used in a unit time
Increase the amount of application data that can be sent
be able to.

As another mode of this embodiment, the hierarchical structure is
The data error of the data link layer 35 remains as it is.
Stop the detection function, and 221 processing unit 36 only
Error in the multiplexed data. In this case, H. 22
1 The error detected by the processing unit 36 is the data link
The correction will be made by the layer 35. That is,
The function of the transport protocol execution unit shown in FIG.
Data link layer 35)
It is.

Thus, in another aspect, the OSI
Error detection performed in the data link layer 35 of the reference model
Output and omit error detection of data signals on the communication line.
Notice H. H.221 based on H.221 221 processing unit 36 only
H. 221 processing unit 36 and data link ray
Layer 35 can avoid duplication of error detection.
Data communication protocol can be simplified.

Hereinafter, a multimedia communication terminal according to the present invention will be described.
A second embodiment of the terminal device will be described. In this embodiment,
Is configured in substantially the same manner as in the first embodiment,
Only the characteristic portions will be described with reference to FIG. First, the configuration will be described. In FIG. The error occurrence probability of the multiplexed data detected by the H.221 processing unit 36 is calculated, and the communication partner whose error occurrence probability is equal to or more than a predetermined value is registered.
A registration unit for this purpose is provided in the RAM 13 of FIG. 2, and the calculation of the error occurrence probability is performed by the system control unit 11. Then, the next time the communication with the partner registered in the RAM 13 is made, Apart from error detection by the H.221 processing unit 36, error detection is performed only on the data signal of the multiplexed data. FIG. 4 shows an embodiment of a hierarchical structure of a data communication protocol provided with error detecting means for this purpose.

In this embodiment, as shown in FIG.
Data link layer 3 having error detection and correction function
5 is used as error detection means, and error detection is performed only on the data signal (telewriting data) separated from the audio signal. It should be noted that the correction of the error detected in the data link layer 35 is performed as it is on the data link layer 3.
5. Further, the correction processing can be executed by the transport layer 33 as described above. The network layer 34 shown in FIG. Since it is unnecessary at the time of data transfer according to the rule of 70NL, it is omitted in this embodiment.

Next, the operation will be described. The data link layer 35 shown in FIG. 1 by the 221 processing unit 36
When a voice signal and a data signal are multiplexed on two B channels, the H.264 standard is used. The error is inserted only when the error occurrence probability per unit time detected at 221 exceeds a predetermined threshold.

Recommendation H. Error checking by CRC4 specified in H.221 is performed 50 times per second. The number of error occurrences in communication is counted, and this is divided by the communication time at the end of communication to obtain the number of error occurrences per unit time. H. 2
Since the 21 processing unit 36 cannot determine whether the error has occurred in the audio signal or the data signal,
When the number of error occurrences increases, the data unit TP shown in FIG.
The number of DU retransmissions increases accordingly. Therefore, when the number of occurrences of errors per unit time in one communication exceeds a certain threshold, in communication with the partner terminal,
The error detection and correction of the data signal are performed by the data link layer 35. In the data link layer 35, an error in a data signal can be separated from that in a voice signal, and correction can be performed only on an error related to a data signal.

FIG. 5 is a diagram showing a data portion to be error-corrected, and FIG. FIG. 2B shows a correction target for an error detected by the 221 processing unit, and FIG. 4B shows a correction target for an error detected by the data link layer. As shown in FIG. 5A, in the above-described first embodiment in which an error is uniformly detected in multiplexed data, H.264 is used. Even when the 221 processing unit 36 detects an error caused by the audio signal portion, the data signal is corrected (retransmitted). In contrast, in the present embodiment, as shown in FIG. 5B, the audio signal is not corrected and only the data signal is corrected, so that the number of retransmissions of the data signal can be reduced.

When the number of errors occurring per unit time exceeds a predetermined threshold, the telephone number and terminal identifier of the partner terminal are registered in the RAM 13 and the next communication is performed with the partner terminal. At the time, communication using the data link layer 35 is executed, and error detection of only the data signal is performed in the data link layer 35. The data link layer 35 includes, as shown in FIG. 221 between the processing unit 36,
Recommendation X. Execute a protocol conforming to G.75. That is, HDLC (High Level Data Link Control Procedure)
re) Perform error detection and recovery processing according to the procedure. In this case, H. The 221 processing unit 36 does not need to notify the data link protocol execution unit (data link layer 35) of the error even if the error is detected. Further, error notification to the transport protocol execution unit (transport layer 33) shown in the above embodiment is not required.

In the present embodiment, the case where the error detection and correction of the data signal is performed in the data link layer 35 has been described, but this can be also performed in the transport layer 33. In this case, CCITT Recommendation X. 224 class 4 must be used. However, when the transport layer 33 is used as the error detecting means in the present embodiment, the class 4 is not used so often and there is a slight difficulty in compatibility. 35
It is more desirable to use. Also, data link layer 3
5. In addition to the transport layer 33, error detecting means may be newly provided.

As described above, in the present embodiment, the data link layer 3
5. Since the error is detected in step 5 and the error correction is performed only for the data signal, the number of data retransmissions can be reduced by the amount that the correction processing for the audio signal is not performed, thereby reducing time or economic loss. Can be. Less than,
Third Embodiment of Multimedia Communication Terminal Device According to the Present Invention
Will be described. This embodiment is different from the second embodiment described above.
The configuration is almost the same as
Only the part will be described.

First, the configuration will be described. According to the protocol configuration shown in FIG. 4, when communicating with a partner registered in the RAM 13, that is, a partner once determined to have a high error occurrence probability, the data link layer 35 detects an error to be corrected. In parallel, H. 221
The error detection by the processing unit 36 is also executed. This H. 221
The probability of occurrence of an error detected by the processing unit 36 is calculated at the end of communication, and the number of continuous communications in which the error occurrence probability has become a predetermined value or less is counted. The counting means for this is provided in the system control unit 11 of FIG. 2, and the system control unit 11 sets the count value when the number of continuous counts of communication in which the error occurrence probability becomes equal to or less than the predetermined value exceeds the set value. Judge that the line quality has recovered or improved. Then, the system control unit 11 stops error detection by the data link layer 35 next time as the return unit of the present embodiment, and returns to H.264 shown in FIG. 221 The processing returns to the protocol configuration in which the error detection is performed only by the processing unit 36.

Next, the operation will be described. When communication is performed with the partner terminal according to the protocol shown in FIG. In some cases, errors detected by the H.221 processing unit 36 decrease. If the communication with the same partner terminal is repeated a predetermined number of times such that the number of times of occurrence of the error becomes smaller than the predetermined threshold value, it is determined that error detection and correction in the data link layer 35 are unnecessary. Then, the protocol is switched again to the protocol shown in FIG. 1 from the next communication.

FIGS. 6 and 7 are flowcharts showing the processing procedure of the present embodiment . FIG. 6 shows a communication operation with an unregistered partner, and FIG. 7 shows a communication operation with a registered partner. . First, at the start of communication, the system control unit 11 checks whether or not a partner terminal is registered in the RAM 13 (step S1), and an unregistered terminal, that is, an error occurrence probability of a predetermined value or more is detected in past communication. If the terminal does not exist, communication is started with the protocol configuration of FIG. 1 (step S2). When the communication starts, the following processing is repeated until the communication ends (step S3). That is, H. 2
Each time 160 octets of multiplexed data is received by the 21 processing unit 36 (step S4), error detection is performed (step S5). If an error is detected, the number of detections is counted up by "+1" (step S5). S6). This counting operation is performed until the end of communication based on the determination in step S3, and the final number of error detections is calculated.

When the communication is completed, the communication time and step S
6, the number of error detections per unit time N, that is, the error occurrence probability, is calculated (Step S).
7) Compare this with a predetermined value (step S8). Here, if NO, that is, if the error occurrence probability N is equal to or less than a predetermined value,
Judging that the line quality is good,
The process is terminated without registering the password (step S9). Note that the communication partner terminal that has been terminated in step S9 will also receive the processing of step S2 and subsequent steps as a non-registered terminal next time.

On the other hand, if the determination in step S8 is YES, that is, if the error occurrence probability N is equal to or more than the predetermined value, it is determined that the line quality is poor, the current partner terminal is registered in the RAM 13 (step S10), and the process ends. . At this time, the count parameter M (= 0) of the number of communication times corresponding to the partner terminal
Is set. The communication partner terminal that has been completed in step S10 will receive the process shown in FIG. 7 next time as a registered terminal.

That is, as shown in FIG. 7, communication with the registered terminal determined as NO in step S1 is started with the protocol configuration of FIG. 4 (step S11). Thereafter, steps S12 to S17 are performed at step S12 in FIG.
The same processing as in steps 3 to S8 is executed, and it is determined whether or not the error occurrence probability N exceeds a predetermined value. If the determination in step S17 is YES, that is, if the error occurrence probability N exceeds the predetermined value, the RAM data relating to the current registered terminal is held continuously, and the communication count parameter M is also left at "0" (step S18). ). In this case, the processing after step S11 is also applied to the next communication with the other party.

On the other hand, if the determination in step S17 is NO, that is, if the error occurrence probability N falls below a predetermined value, "+1"
Then, the communication count parameter M is counted up (step S19), and it is checked whether or not the parameter M exceeds a set value (step S20). That is, it is determined whether or not the communication in which the error occurrence probability N is smaller than the predetermined value has continued for the same registered terminal for the set number of times or more, and if NO, the parameter M counted up by M + 1 → M in step S19. Then, the registered contents of the RAM 13 are changed (step S21). Also in this case, the processing after step S11 is applied at the time of the next communication with the other party. If an error occurrence probability N exceeding a predetermined value is detected before the number of continuous communications M in which the error occurrence probability N falls below a predetermined value reaches a set value, M is cleared to 0 in step S18. .

Next, if the determination in step S20 is YES, that is, if the communication in which the error occurrence probability N is less than the predetermined value continues for the same registered terminal for a set number of times or more, the registration of the current partner is deleted from the RAM 13. (Step S
22), end the process. In this case, at the time of the next communication with the other party, the process returns to the process after step S2 in FIG.

As described above, in the present embodiment, even if the error occurrence probability N is high and once the error detection by the data link layer 35 shown in FIG. As shown in FIG. 221 processing unit 3
6, the protocol can be simplified, the amount of communication data can be reduced, and communication adapted to communication quality can be performed reversibly.

[0050]

As described above, according to the multimedia communication terminal apparatus of the present invention, the data error detection function of the data link layer is stopped, and only the multiplex processing unit detects an error in the multiplexed data. Therefore, it is possible to avoid duplication of error detection by the multiplex processing unit and the data link layer, and to simplify the data communication protocol.

[0051] Also, O SI reference model data link layer and omit the network layer, to position the multiple processing unit in lower transport layer of the OSI reference model
This can simplify the protocol,
Since the header part of the data is reduced by omitting the layer,
Communication data can be reduced, and conversely, the amount of application data that can be transmitted per unit time can be increased.

[0052] When the error probability of the multiplexed data detected by multiplex processing unit exceeds a predetermined value, to register the communication partner registration means, when communicating next with partner registered Is to perform error detection by the error detection means only on the data signal of the multiplexed data .
If this is the case , the number of retransmissions of data can be reduced as much as no correction processing is performed on the audio signal, and time or economic loss can be reduced.

[0053] In addition, when communicating with the registered have been the other party,
The number of continuous communications, in which the probability of occurrence of an error detected by the multiplex processing unit has become equal to or less than a predetermined value, is counted by the counting means, and when the counted number of continuous times exceeds the set value, the returning means uses the error detecting means. stop the error detection, so as to return to the error detection by only the multiplexing processing unit
If the probability of error occurrence is high and once switching to error detection of only the data signal by the error detection means is performed, when the error occurrence probability becomes low, the multiplex processing unit automatically detects uniform error in the multiplexed data. Switching can be performed, and communication adapted to communication quality can be reversibly executed while simplifying the protocol and reducing the amount of communication data.

[Brief description of the drawings]

FIG. 1 is a diagram showing a multimedia communication terminal device according to the present invention;
FIG. 2 is a configuration diagram illustrating a hierarchical structure of a data communication protocol in one embodiment .

FIG. 2 is a diagram showing a multimedia communication terminal device according to the present invention;
It is a lineblock diagram showing one example .

FIG. 3 is a communication flowchart showing an error correction sequence according to the data communication protocol of FIG.

FIG. 4 is a diagram showing a multimedia communication terminal device according to the present invention;
It is a hierarchical structure which shows the data communication protocol in 2 Example .

FIG. 5 is a diagram showing an error correction target data portion, and FIG. FIG. 2B shows a correction target for an error detected by the 221 processing unit, and FIG. 4B shows a correction target for an error detected by the data link layer.

FIG. 6 shows a multimedia communication terminal device according to the present invention.
It is a flowchart which shows the processing procedure at the time of communication of 3rd Example .

FIG. 7 is a flowchart following FIG. 6;

Claims (8)

(57) [Claims] 1. A multiplexing unit having a multiplexing function for multiplexing a voice signal and a data signal on one communication channel and a function of detecting an error of multiplexed data, and a multiplexing unit for the data signal corresponding to an OSI reference model. A data link layer having an error detection and correction function, wherein the multiplex processing unit is positioned below the data link layer. A multimedia communication terminal device, wherein an error in multiplexed data is detected only by a processing unit. 2. The multimedia communication terminal device according to claim 1, wherein the data link layer and the network layer of the OSI reference model are omitted in the communication of the data signal, and
A multimedia communication terminal device located below a transport layer of an I reference model. 3. A multimedia communication terminal apparatus according to claim 1 or 2 wherein, a registration unit configured error probability of the multiplexed data detected by the multi-processing unit registers for a communication partner becomes equal to or greater than a predetermined value, the multi Exists in a layer different from that of the
When and a error detection unit for performing error detection only data signal, to communicate with the other party registered in the registration means, Day
Error detection only by the error detection means
Multimedia communication terminal apparatus and performs. 4. The multimedia communication terminal device according to claim 3, wherein the number of continuous communications in which the probability of occurrence of an error detected by a multiplex processing unit in communication with a registered partner has fallen below a predetermined value is counted. Multimedia communication, comprising: counting means; and return means for stopping error detection by the error detection means and returning to error detection by only the multiplex processing unit when the number of continuous times exceeds a set value. Terminal device. 5. A multiplexing unit having a multiplexing function for multiplexing a voice signal and a data signal on one communication channel and a function of detecting an error of multiplexed data, and a separate multiplexing unit for the data signal corresponding to an OSI reference model. A data link layer having an error detection and correction function of the multimedia communication terminal device in which the multiplex processing unit is positioned below the data link layer, wherein the data error detection function of the data link layer is stopped and A multimedia communication terminal device, wherein an error in multiplexed data is detected only by a multiplex processing unit. 6. The multimedia communication terminal device according to claim 1, wherein the data link layer and the network layer of the OSI reference model used in the data communication protocol are omitted, and the multiplex processing unit uses the data communication protocol. A multimedia communication terminal device positioned below a transport layer of an OSI reference model to be used. 7. The multimedia communication terminal device according to claim 1, wherein the error occurrence probability of the multiplexed data detected by the multiplexing processing unit is equal to or more than a predetermined value. Registration means for registering a communication partner registered, and error detection means other than a multiplex processing unit for performing error detection on a data signal of multiplexed data when communicating with the registered partner. Media communication terminal device. 8. The multimedia communication terminal device according to claim 7, wherein the number of continuous communications in which the probability of occurrence of an error detected by a multiplex processing unit in communication with a registered partner has become equal to or less than a predetermined value is counted. Counting means; and return means for stopping error detection by error detection means other than the multiplex processing unit and returning to error detection by only the multiplex processing unit when the number of consecutive times exceeds a set value. Multimedia communication terminal device.