JPH1155345A - Communication device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a communication device for transmitting and receiving multimedia information in units of frames, and to efficiently transmit acknowledgment (ACK / NAK) while minimizing deterioration in transmission efficiency of various information. . An acknowledgment transmission interval management unit (70a) that stores a reference interval related to the transmission of acknowledgment, a acknowledgment transmission interval measurement unit (70b) that measures the time elapsed since the last transmission of the acknowledgment, A constant interval progress notification unit 70c that detects and notifies that the time or the like has exceeded the reference interval, a transmission priority management unit 80a that stores a priority when transmitting audio information, image information, data, and delivery confirmation;
A frame determining unit 80 that determines a format of a frame to be transmitted next based on the notification and the priority order;
A multiplexing unit 50 and a communication control unit 60 for transmitting a frame according to the determined format are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus for multiplexing information of different types, such as images, sounds, and data, and transmitting and receiving the information in a limited transmission band in real time. Related to the technology of return.

[0002]

[Related Art] In recent years, multimedia communication for transmitting and receiving voice, image, and data has attracted attention, and various devices and software for that purpose have been developed. Video conference systems and videophones are typical examples. These multimedia communication terminals must transmit and receive voice, image and data within a limited transmission band (for example, when using PHS, one line 32kbp
s). Here, the data refers to digital information of a type different from digital information (audio information, image information) representing audio and images, and is, for example, a program code.

As an effective means for transmitting and receiving multimedia information including voice, image, data, and the like in a limited transmission band, there is a method of multiplexing these different types of information into one frame for communication. For example, the proposed ITU-T recommendation ITU-T for real-time communication of voice, images and data
-T DRAFT RECOMMENDATION H.223 / ANNEX A (December 6, 1996
Day) is also one of the methods for multiplexing and transmitting different types of information into one frame.

FIG. 17 is an external view showing an example of a case where a system for multiplexing voice, image, and data into one frame and transmitting / receiving the same in accordance with the above-mentioned recommendation is realized. This system includes two composite terminals 100 and 200 using a PHS telephone. These composite terminals 100 and 2
00 denotes a camera 101 for capturing an image, respectively.
And 201, antennas 102 and 202, display screen 10
3 and 203, speakers 104 and 204, microphone 10
5 and 205 and a keypad 106.

In FIG. 1, audio and video are transmitted in both directions, and data is transmitted in one direction (from the composite terminal 100 to the composite terminal 20).
0) is shown. The frame structure is based on the data communication standard PHS INTERNET ACCESS FORUM ST defined by the PHS Internet Access Forum.
It shall conform to ANDARD (PIAFS) 1st edition. That is,
Voice, image, data, and the like are multiplexed and mapped into a 640-bit fixed-length frame and transmitted and received.

FIG. 18 shows the above-mentioned composite terminals 100 and 200.
FIG. 3 is a functional block diagram showing the internal configuration of the device. The data input / output unit 10 includes a keypad 106, a data operation circuit, and the like, and generates data to be transmitted and executes an operation process using the received data. The voice input / output unit 11
Speakers 104 and 204, microphones 105 and 205,
It is composed of an audio codec or the like, and generates audio information to be transmitted and reproduces the received audio information.

The image input / output unit 12 includes cameras 101 and 2
01, display screens 103 and 203, an image codec, etc., for generating image information to be transmitted and for reproducing the received image information. The temporary storage units 20 to 22
These are buffers for temporarily storing data or audio information and image information relating to transmission or reception.

The protocol processing units 30 to 32 perform communication processing (processing corresponding to a higher layer than the physical layer) specific to data, audio information, and image information, respectively, according to the protocol specified in the above-mentioned recommendation proposal and the communication standard. Do. More specifically, when data / audio information / image information to be transmitted is generated as a transmission process, the fact and the amount are notified to the frame determination unit 40 or stored in the temporary storage units 20 to 22. The transmission data / audio information / image information read out is added to a CRC and a sequence number for error detection and correction, and then passed to the multiplexing unit 50. Further, as the reception processing, the reception data / audio information /
After receiving the image information and performing error detection and correction based on the CRC added thereto, the image information is stored in the temporary storage unit 20 or a retransmission request is issued to the communication partner.

The frame determining unit 40 receives, from each of the protocol processing units 30 to 32, a notification about the presence / absence of data / audio information / image information to be transmitted and the amount thereof.
A format to be used for the next transmission is determined from a plurality of types of predetermined frame formats, and the result is notified to the multiplexing unit 50. 2 (a) and 2 (b)
FIG. 3 is a diagram showing a plurality of types of frame formats.

FIG. 2A shows a format in which information of all types of audio, image and data can be transmitted at the same time, and FIG. 2B shows a format in which only audio and image can be transmitted at the same time. Format. The header includes a format identifier for specifying the type of the frame format. The frame determining unit 40 adopts the format a shown in FIG. 2A when data to be transmitted remains, and employs the format a shown in FIG. 2B when there is no data to be transmitted. The format b shown in FIG. In the above H.223 / ANNEX A, it is necessary to unify these formats between the complex terminal 100 and the complex terminal 200, but ITU-T DRAFT RECOMM
It is also possible to determine dynamically by negotiation according to the procedure described in ENDATION H.245.

The multiplexing unit 50 generates a frame by multiplexing the information processed in each of the protocol processing units 30 to 32 according to the frame format determined by the frame determining unit 40 and sends the frame to the communication control unit 60. By interpreting the header of the frame received by the communication control unit 60, the frame is separated into audio information, image information, and data, and then distributed to each of the protocol processing units 30 to 32.

The communication control unit 60 includes a modem and an antenna 1
02 and 202, and the like. The 640-bit frame generated by the multiplexing unit 50 is modulated according to the PHS communication procedure and then transmitted wirelessly, or the frame wirelessly transmitted from the communication partner is received and demodulated and then multiplexed. To the conversion unit 50. As described above, a system for transmitting and receiving multimedia information including voice, image, and data within a limited transmission band is constructed.

[0013]

However, the above system has the following unsolved problems. In other words, if the data is of a type that does not allow a transmission error, that is, the receiving side sends a notification (delivery acknowledgment) of whether the data has been correctly received (acknowledgement; ACK) or not (negative acknowledgement; NAK). In the case where the data has to be returned to the transmitting side, an efficient delivery confirmation return method in consideration of the influence on the transmission efficiency of each of voice, image, and data (substantial reduction in transmission speed) has not yet been proposed.

[0014] Here, if the system is limited to a system that transmits and receives only a single type of information instead of multimedia information, there is a conventional technology that avoids a decrease in data transmission efficiency by reducing the transmission frequency of acknowledgment. . For example, the transmitting side attaches a sequence number to data and continuously transmits data frames of a plurality of sequence numbers collectively, and the receiving side returns a delivery confirmation for the group of data to the transmitting side, so that the transmitting side transmits the data frame. The side knows that the data has been transmitted to the receiving side without error.

Specifically, in a high-level data link control (HDLC) procedure, which is a Japanese Industrial Standard, the transmitting side continuously transmits data frames of a predetermined outstanding number, and the receiving side transmits a monitoring type RR. A command and RR response return data delivery confirmation to the sender (however, in the HDLC procedure,
It is not specified except when requested by the sender. ).

These prior arts are systems in which only a single type of information is transmitted / received and only the transmission efficiency of the information is considered, and a system in which a plurality of types of information such as voice, image and data are transmitted / received. Is not a technique for improving the transmission efficiency of the entire system while considering the characteristics of each information. That is, simply returning the delivery confirmation prior to voice information or image information and returning it frequently can improve the data transmission efficiency because the data transmission side can obtain a detailed delivery confirmation, but the voice transmission efficiency is improved. The transmission speed of information and image information decreases, and real-time conversation with images becomes difficult. Conversely, if the transmission interval of the delivery confirmation is simply increased, the transmission speed of the voice information and the image information is maintained, but the transmission efficiency of the data is reduced and the necessary program codes are not transmitted. .

The present invention has been made in view of the above points, and is a communication apparatus for transmitting and receiving a plurality of types of information such as images, voices, and data. A first object is to provide a communication device capable of efficiently transmitting an acknowledgment while taking into account the characteristics (real-time property, etc.) of each information, while minimizing the transmission time.
The purpose of.

A second object of the present invention is to provide a flexible communication apparatus capable of changing the frequency of transmitting the acknowledgment according to a change in the communication condition.

[0019]

In order to achieve the above object, the present invention provides a first type information requiring a delivery confirmation,
A communication device for multiplexing multimedia information including second type information of a type different from the first type information and transmitting / receiving the frame information in units of frames, wherein a certain period of time has elapsed since the last transmission of an acknowledgment. Means for detecting the elapse of a predetermined period of time for detecting,
Acknowledgment transmitting means for transmitting a frame including acknowledgment for the type information, wherein the acknowledgment transmitting means stores a priority for transmission of the acknowledgment, the first type information and the second type information, A frame determination unit that determines a frame format including at least one of a delivery confirmation, first type information, and second type information to be transmitted in accordance with the priority order stored in the priority order storage unit; And a transmission unit for transmitting a frame according to the following.

As a result, even when it is necessary to continuously transmit acknowledgments, the acknowledgments are spaced at least for a certain period of time and have priority over other information to be transmitted. Sent in consideration of. Accordingly, a communication device that minimizes a decrease in the transmission efficiency of such information and efficiently transmits a delivery confirmation while considering the characteristics of each information reflected in the priority order is realized.

In a communication system in which images, sounds, data, and the like are multiplexed and transmitted / received in real time in a limited transmission band, the data receiving side transmits the data transmission confirmation from the previous transmission to the next transmission. It has a function to manage the reference acknowledgment transmission timing and a function to manage the transmission priority for various types of information including the acknowledgment, and sets the above two parameters (delivery acknowledgment transmission timing and transmission priority) to the transmission quality. Or the amount of information to be transmitted may be changed.

[0022] This realizes a flexible communication device in which the frequency of transmitting the delivery confirmation is changed according to the change in the communication situation.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the communication device according to the present invention will be described below with reference to the drawings. The communication apparatus is a composite terminal using a PHS telephone, and is common to the above-described related art in that the PHS telephone composite terminal system shown in FIG. 17 is configured. This system is compatible with the above ITU-T DRAFT RECOMMENDATION
In accordance with H.223 / ANNEX A, audio, video, and data that does not allow transmission errors are multiplexed into one frame for transmission and reception. The frame is a data communication standard PHS INTE specified by the PHS Internet Access Forum.
According to RNET ACCESS FORUM STANDARD (PIAFS) 1st edition 6
It has a fixed length of 40 bits. (Embodiment 1) First, the composite terminal 1 according to Embodiment 1
10 and 210 will be described.

Composite terminals 110 and 2 according to Embodiment 1
10 is characterized by having both a function of managing the transmission interval of the delivery confirmation and a function of managing the priority when transmitting various types of information. FIG. 1 shows a PH according to the first embodiment.
FIG. 3 is a functional block diagram showing a configuration of S-phone combined terminals 110 and 210. This figure is the same as FIG. 1 in the related art described above.
8, corresponding to the above-described related art, is a block surrounded by a solid line, and is denoted by the same reference numeral. Components that differ from the related art described above are:
This is a block surrounded by a dotted line.

The composite terminals 110 and 210 include a data input / output unit 10, a voice input / output unit 11, an image input / output unit 12, temporary storage units 20 to 22, a data protocol processing unit 70,
It is composed of audio and image protocol processing units 31 and 32, a frame determination unit 80, a multiplexing unit 50, and a communication control unit 60. The protocol processing unit 70 includes an acknowledgment transmission interval management unit 70a, an acknowledgment transmission interval measurement unit 70b, and a constant interval progress notification unit 70c, in addition to the functions of the protocol processing unit 30 in the related art described above.
Similarly, the frame determining unit 80 includes a transmission priority managing unit 80a in addition to the functions of the frame determining unit 40 in the related art described above. Hereinafter, a description will be given focusing on differences from the configuration in the related art described above.

The acknowledgment transmission interval management unit 70a is a RAM
And the like, and stores a reference interval from the previous transmission of the delivery confirmation for the received data to the next transmission. Here, the reference interval is two parameters that specify the minimum transmission interval of delivery confirmation, that is, the reference type (based on the number of frames including data, or from the previous transmission to the next transmission). And the reference amount (the number or the elapsed time). In the present embodiment, the delivery confirmation transmission interval management unit 70a stores the reference type “frame” and the reference amount “5” as initial values. This means that the next acknowledgment is not transmitted until at least five frames including data are received.

The acknowledgment transmission interval measuring unit 70b is composed of a counter, a timer, and the like, and measures an interval since the acknowledgment was transmitted last time. Specifically, the protocol processing unit 70
Is transmitted (the multiplexing unit 50)
Resets the internal counter and timer, and records and updates the number of received frames that contain data in the counter, and the elapsed time from the reset in milliseconds. Record is updated in units.

The constant interval elapse notifying unit 70c constantly monitors whether the values of the counter and the timer of the acknowledgment transmission interval measuring unit 70b match or exceed the reference interval stored in the acknowledgment transmission interval management unit 70a. When it is detected that the reference interval stored in the transmission confirmation transmission interval management unit 70a has elapsed, the transmission unit 40 notifies the frame determination unit 80 that a transmission confirmation to be transmitted has occurred. For example, when the reference type “frame” and the reference amount “5” are stored in the delivery confirmation transmission interval management unit 70a, the constant interval progress notification unit 70c
Notifies the frame determination unit 80 that an acknowledgment to be transmitted has occurred when the count value of the acknowledgment transmission interval measurement unit 70b has reached “5”.

The transmission priority management section 80a is composed of a RAM or the like, and stores four types of information, that is, data, voice information, image information, and transmission priority for transmission confirmation.
Specifically, as an initial value, the order of voice information, data, delivery confirmation, and image information is stored in descending order of priority. The frame determining unit 80 includes a protocol processing unit 70,
The contents notified from 30 and 31 (data / audio information / image information / delivery confirmation to be transmitted and the amount of the data / audio information / image information to be transmitted) and the transmission priority management unit 80a store the contents. One of three predetermined frame formats is determined in accordance with the priority order, and the result is notified to the multiplexing unit 50. The frame determination unit 80 repeats the determination and notification each time one frame is transmitted, as long as any of the data / audio information / image information / delivery confirmation to be transmitted remains untransmitted. As a result, untransmitted data / audio information /
The transmission of the frame is repeated until there is no image information / delivery confirmation.

FIGS. 2A to 2C are diagrams showing these three types of frame formats. In addition to the two types of formats (FIGS. 2 (a) and 2 (b)) used in the related art described above, a format c (sound, image, and delivery confirmation) shown in FIG. A format for transmitting information simultaneously) has been newly added.

FIG. 3 shows a flow of determining a frame format by the frame determining section 80. Frame determination unit 8
In the case where 0 has been notified that data to be transmitted has been generated from the protocol processing unit 70, format 0 is adopted until all the data has been transmitted (step S300). On the other hand, when there is no data to be transmitted, the format c is adopted when the notification indicating that the transmission confirmation to be transmitted has occurred has been received from the fixed interval elapse notifying unit 70c (steps S301 and S303). If the notification has not been received, format b is adopted (steps S301 and S304).

In this figure, the presence or absence of audio information to be transmitted is not determined because the same amount of audio information is included in any of the above three formats in order to ensure real-time voice communication. The reason why the presence / absence of image information to be transmitted is not determined is that the priority of the image information is the lowest, and that all of the data to be transmitted, the delivery confirmation, and the image information have occurred. Format b including image information as default even if not present
This is because it is adopted. The reason why the presence / absence of data (step S300) is determined before the presence / absence of delivery confirmation (step S301) is that the determination is made according to the priority stored in the transmission priority management unit 80a.

Next, the composite terminal 1 configured as described above
The operation in the case where 10 and 210 communicate will be described. Note that, similarly to the related art described above, the composite terminal 110 transmits data, audio information, and image information to the composite terminal 210, while the composite terminal 210
It is assumed that transmission confirmation, audio information, and image information are transmitted to.

FIG. 4 is a sequence diagram showing the exchange of frames centering on the operation of the composite terminal 210 on the data receiving side. According to this figure, the composite terminal 21
The operation 0 will be mainly described in relation to the transmission of the acknowledgment. FIG. 4 is a sequence diagram showing the exchange of frames with a focus on the operation of the composite terminal 210 on the data receiving side. With reference to the figure, the operation of the composite terminal 210 will be described focusing on the part related to the transmission of the delivery confirmation.

In the figure, ten frames 400 arranged in the left column show the received frames transmitted from the composite terminal 110 in time series, while nine frames 402 arranged in the right column represent the composite frames 210 in the right column. Shows the transmission frames transmitted by the chronological order. Also, the time axis 401 shown in the center
Indicates the timing at which the composite terminal 210 transmits and receives frames.

The symbols (H, A, D) in each frame
(n), V, and D (n *)) correspond to the types of information shown in FIGS. Note that n in the symbol D (n)
Is a sequence number added by the protocol processing unit 70, and manages transmission of data without error in units of frames. The symbol D (n *) is
This is a delivery acknowledgment for the data up to the already received data D (n-1), and at the same time indicates that it is ready to receive the next data D (n).

Now, at time t1, the composite terminal 210
Is assumed to have transmitted an acknowledgment D (1 *) for the received data D (0). At the same time as the transmission, the transmission confirmation transmission interval measuring section 70b starts measuring the interval until the next transmission of the transmission confirmation. Specifically, the transmission confirmation transmission interval measuring unit 70
b resets the internal counter and timer, and records and updates the number of frames received afterwards, including data, in the counter, and records and updates the elapsed time since the reset in milliseconds. To go. This measurement is continued until the next acknowledgment is transmitted, specifically, until the acknowledgment created by the protocol processing unit 70 is read out to the multiplexing unit 50.

In the period from time t2 to time t3, only information to be transmitted is audio information and image information.
0 transmits to the composite terminal 110 four frames in the format b shown in FIG. At time t3, the count value of the acknowledgment transmission interval measuring unit 70b becomes “5”, so the constant interval elapse notifying unit 70c uses the count value “5” and the reference value stored in the acknowledgment transmission interval management unit 70a. It detects that the quantity “5” matches, and notifies the frame determination unit 80 that a delivery confirmation to be transmitted has occurred. Then, the protocol processing unit 70 creates a delivery confirmation D (6 *), which is frame data for that purpose, and adds a CRC bit to the delivery confirmation D (6 *) to prepare for transmission of the delivery confirmation.

At time t3, the frame determining unit 80, which has received the notification from the constant interval elapse notifying unit 70c, has not generated any data to be transmitted (not transmitted) but has transmitted the audio information and image data to be transmitted. Information and acknowledgment have occurred (being present), and transmission priority management unit 80a
, It is determined that the format c shown in FIG. 2C should be adopted according to the determination flow shown in FIG.

As a result, immediately after time t3, composite terminal 210 transmits a frame including acknowledgment D (6 *) indicating that data D (1) to D (5) has been correctly received to composite terminal 1.
Send to 10. When this acknowledgment D (6 *) is transmitted, the acknowledgment transmission interval measurement unit 70b resets the internal counter and timer and starts measuring the transmission interval again, and the constant interval progress notification unit 70c It monitors whether the values of the counter and the timer match or exceed the progress criterion stored in the delivery confirmation transmission interval management unit 70a. In this way, the composite terminal 210 repeats the operation of returning one acknowledgment to the communication partner every time a frame including five data is received.

As described above, according to the present embodiment, the protocol processing unit 70 for performing data transmission sequencing, error detection, and data retransmission manages the reference interval for intermittently transmitting data delivery confirmation. Means 70a to
70c, for each type of information to be transmitted in the frame determination unit 80 that determines the format of the multiplexed frame to be transmitted (data / voice information / image information / delivery confirmation).
By providing the means 80a for managing the priority of the data, it is possible to return a delivery confirmation for the received data without lowering the transmission efficiency of audio information and image information (information other than data). That is, not only the transmission frequency of the transmission confirmation is reduced, but also the transmission control of the transmission confirmation in consideration of the priority for each type of information to be transmitted.

Note that, in the above embodiment, the composite terminal 21
Although it is assumed that data to be transmitted does not occur at 0, the present invention is not limited to such a case. For example, when data to be transmitted occurs at time t3 in the above embodiment, format a is adopted until all the data is transmitted, and the transmission confirmation is not necessarily performed immediately after time t3. There is no guarantee that D (6 *) will be sent. Therefore, when the created delivery confirmation D (6 *) is not transmitted, the protocol processing unit 70 counts up without resetting the contents of the delivery confirmation transmission interval measuring unit 70b. May be created while updating the delivery confirmation D (n *) corresponding to. This way, even if no acknowledgment is sent immediately after the reference interval is reached,
An acknowledgment for the data received immediately before is prepared and transmitted.

If data to be transmitted from the complex terminal 210 to the complex terminal 110 frequently occurs, a delivery confirmation is made for each frame (data frame) as specified in the HDLC procedure. By giving, a rule may be provided such that transmission data and transmission confirmation are always transmitted in pairs. For example, when data to be transmitted is generated, a format in which delivery confirmation is included in the data of format a is adopted, and when data to be transmitted is not generated, the procedure in this embodiment is used. It can also be combined to take. Thereby, the transmission efficiency of the data and the delivery confirmation is improved.

Further, when a transmission error occurs in data to be transmitted / received, an existing retransmission processing procedure (for example, GOBACKN which is a procedure for “retransmitting all frames after a transmission error occurs” at the time when the transmission error occurs) is performed. Or Selectiv, a procedure that retransmits only frames with transmission errors
By performing retransmission processing based on (eRepeat), an efficient data transmission method can be established while maintaining data quality.

In the present embodiment, the transmission priority management unit 80a is provided in the frame determination unit 80.
It may be provided in each of the protocol processing units 70, 30, and 31, and the frame determination unit 80 may access these to determine a transmission frame. (Embodiment 2) Next, the composite terminal 1 according to Embodiment 2
20 and 220 will be described.

Composite terminals 120 and 2 according to Embodiment 2
No. 20 is characterized in that, when the timing of transmitting the acknowledgment is later than expected, the priority of transmitting the acknowledgment is changed to be higher. FIG. 5 shows a PH according to the second embodiment.
FIG. 2 is a functional block diagram showing a configuration of S-phone combined terminals 120 and 220.

The second embodiment differs from the first embodiment in that a delivery confirmation transmission delay notifying unit 70 d is added to the protocol processing unit 70 and the transmission priority changing unit 8 is added to the frame determining unit 80.
0b is added. Components 10 to 12, 20, 22, 31, 32, and 7 common to the first embodiment
Descriptions of 0, 70a to 70c, 80, 80a, 50, and 60 are omitted.

The acknowledgment transmission delay notifying section 70d is configured not to transmit the acknowledgment immediately after the elapse of the reference interval stored by the acknowledgment transmission interval management section 70a. (A delay amount) to the frame determination unit 80. Specifically, of the counter and timer values of the acknowledgment transmission interval measurement unit 70b, the value corresponding to the reference type stored in the acknowledgment transmission interval management unit 70a is monitored, and each time the value is updated, The difference between the value and the reference amount stored in the delivery confirmation transmission interval management unit 70a is calculated, and the difference is notified to the transmission priority changing unit 80b as the delay amount.

In this embodiment, the acknowledgment transmission interval management section 70a stores the reference type “frame” and the reference amount “5” as the reference interval. Becomes "6", the difference "1" is notified, and when the count value becomes "8", the difference "3" is notified. The transmission priority change unit 80b changes the priority stored in the transmission priority management unit 80a according to the delay amount notified from the acknowledgment transmission delay notification unit 70d. Specifically, the transmission priority changing unit 80b reads out the reference amount stored in advance in the acknowledgment transmission interval management unit 70a, and sets the delay amount notified from the acknowledgment transmission delay notification unit 70d to the reference amount. Each time it exceeds half, the priority for data and delivery confirmation is changed by one. In the present embodiment, half of the reference amount stored in the delivery confirmation transmission interval management unit 70a is “2.
5 ", the priority stored in the transmission priority management unit 80a is read every time the delay amount notified from the delivery confirmation transmission delay notification unit 70d becomes 3, 5, 8,. The order is updated so that only one of the two types of information, ie, the acknowledgment and the delivery confirmation, has a higher priority.

If the priority of data or delivery confirmation becomes the highest as a result of the change, no further update is performed. When the acknowledgment is transmitted, the initial priority is written back to the transmission priority management unit 80a in order to reset the previous change. Next, an operation when the composite terminals 120 and 220 configured as described above communicate will be described.

FIG. 6 is a sequence diagram showing the exchange of frames centering on the operation of the composite terminal 220 on the data receiving side. This figure is a figure corresponding to FIG. 4 in the first embodiment. Note that, similarly to the case of the first embodiment, the composite terminal 120 transmits data, audio information, and image information to the composite terminal 220, while the composite terminal 2
20 transmits transmission confirmation, voice information and image information to the composite terminal 120, and the frame format adopted by the frame determination unit 80 is shown in FIGS. 2 (a) to 2 (c).
And a delivery confirmation transmission interval management unit 70a
Are the reference type “frame” and the reference interval “5”. However, unlike the first embodiment, the initial priorities stored in the transmission priority management unit 80a are, as shown in the row from time t1 to time t5 in FIG. Image information, data, and delivery confirmation.

FIG. 7 is a diagram showing the stored contents (priority) of the transmission priority management unit 80a at each time shown in FIG. 6, and the manner in which the priority is changed by the transmission priority changing unit 80b. FIG. Now, suppose that the composite terminal 220 has transmitted the delivery confirmation D (1 *) for the received data D (0) at time t1, as in the case of the first embodiment.

Immediately after this, the transmission priority changing unit 8
Since 0b resets the contents (priority) of the transmission priority management unit 80a, the priority is in the order shown in the row from time t1 to t5 in FIG. As a result, the frame determination unit 80 determines the format of the transmission frame according to the determination flow shown in FIG. FIG. 8 is a diagram showing a flow of determining a frame format in the order of priority shown in the row at times t1 to t5 in FIG.

The frame determination unit 80 determines whether there is any data to be transmitted at that time in the order of image information, data, and delivery confirmation, and if so, adopts formats b, a, and c, respectively. If neither exists, format b is adopted as a default. In this decision flow, the reason why the presence / absence of audio information to be transmitted is not determined is that the same amount of audio information is included in each format. The reason is that the judgment is made in accordance with the priority stored in the transmission priority changing unit 80b.

As described above, since only the audio information and the image information to be transmitted are generated in the composite terminal 220 between the times t2 and t3, the frame determining unit 80 determines to use the format b. (Step S31
0, S313), the composite terminal 220 transmits four frames of format b. At time t3, as in the first embodiment, the constant interval elapse notification unit 70c notifies the frame determination unit 80 that the acknowledgment transmission reference interval has elapsed (that is, the acknowledgment transmission request), and the protocol processing unit 70 prepares for the creation and transmission of the delivery confirmation D (6 *). Thus, at this time t3, a delivery confirmation to be transmitted has occurred.

However, the frame determination section 80 determines to adopt the format b in order to follow the determination flow shown in FIG. Therefore, until then (at time t2
As in the case of to t3), only the audio information and the image information are transmitted, and the state in which the delivery confirmation is not transmitted continues (time t3 to t5). At time t4, the protocol processing unit 70 knows that the frame including the new data D (6) has been received without transmitting the prepared acknowledgment D (6 *). D (6 *) is discarded, and a new delivery confirmation D (7 *) is created and prepared. further,
The acknowledgment transmission delay notifying unit 70d transmits the difference “1” between the count value “6” of the acknowledgment transmission interval measuring unit 70b and the reference amount “5” stored in the acknowledgment transmission interval management unit 70a as a delay amount. The priority changing unit 80b is notified. Upon receiving the notification, the transmission priority changing unit 80b sets the delay amount “1”.
And a threshold value “2.5” stored in advance.
As a result, since the delay amount has not reached the threshold value, the transmission priority changing unit 80b maintains the content of the transmission priority managing unit 80a without changing it.

However, at time t5, the delivery confirmation transmission delay notifying section 70d notifies the transmission priority changing section 80b of the delay amount "3". It is determined that “3” exceeds the threshold value “2.5”, and the storage content of the transmission priority management unit 80a is updated. In other words, the priority is changed to a new priority (priority shown at times t5 to t6 in FIG. 7) in which the priority for data and delivery confirmation is increased by one from the prior priority.

The new priority is the same as the priority in the first embodiment.
Specifies the format of the transmission frame according to the decision flow shown in FIG. Therefore, at time t5,
What is to be transmitted is audio information, image information, and acknowledgment, but the frame determination unit 80 determines the next transmission frame to be format c according to the determination flow of FIG.

As a result, at time t6, a frame in format c including the delivery confirmation D (9 *) prepared immediately before by the protocol processing unit 70 is transmitted to the composite terminal 120. As described above, according to the present embodiment, a communication device or a communication system provided with the following determination rule regarding the transmission timing of the delivery confirmation is realized.

After the elapse of the reference interval, a delivery confirmation is transmitted at a timing when the amount of information other than data is small. However, the transmission priority of the delivery confirmation is set low. If the amount of information other than data is always large after the elapse of the reference interval and the timing to send the acknowledgment cannot be found, the transmission priority is changed (increased) according to the delay from the reference interval, and the acknowledgment is performed. Can be sent.

That is, according to the second embodiment, the acknowledgment transmission delay notifying unit 70d is provided in the protocol processing unit 70, the transmission priority changing unit 80b is provided in the frame determining unit 80, and the transmission acknowledgment is transmitted from the reference interval. By changing the transmission priority according to the transmission confirmation transmission delay level and determining the timing of transmitting the transmission confirmation, the transmission confirmation is effectively transmitted using the timing when the amount of information to be transmitted other than the data to be transmitted is small. can do. (Embodiment 3) Next, the composite terminal 1 according to Embodiment 3
30 and 230 will be described.

Composite terminals 130 and 2 according to Embodiment 3
30 is characterized in that, when it is necessary to retransmit an image, the priority of transmitting the acknowledgment is changed to be lower. FIG. 9 shows a PHS telephone composite terminal 130 according to the third embodiment.
And FIG. 230 is a functional block diagram showing the configuration of FIG. The difference from the first embodiment is that the composite terminals 130 and 230 of the present embodiment are different from the protocol processing unit 7 having the image information retransmission management unit 71a in place of the protocol processing unit 32 of the first embodiment.
1 and that a transmission priority changing unit 80b is added to the frame determining unit 80. Components 10 to 12, 20 to 22, 31, 7 common to the first embodiment
Descriptions of 0, 70a to 70c, 80, 80a, 50, and 60 are omitted.

The image information retransmission management section 71 a
30 to determine whether there is image information to be retransmitted, if there is image information to be retransmitted, determine and store the retransmission frame length, and notify the frame determination unit 80 that image information to be retransmitted has occurred. It has a function to do. Specifically, it is determined whether or not the received frame includes a request to retransmit the image information. If the request is included, the information amount (retransmission frame length) specified together with the request is further determined. ) Is detected.

When the transmission priority changing unit 80b receives a notification from the image information retransmission management unit 71a that image information to be retransmitted has occurred, the transmission priority changing unit 80b gives priority to the image information until the image information is transmitted. Transmission priority management unit 8 so that it is transmitted
It has a function of changing the transmission priority stored in 0a.
Specifically, the transmission priority changing unit 80b receiving the notification
Lowers the priority of data and delivery confirmation by one by rewriting the priority stored in the transmission priority management unit 80a, and after the image information to be retransmitted is transmitted,
Restores the priorities before the change.

Next, the composite terminal 1 configured as described above
The operation in the case where the devices 30 and 230 communicate will be described. FIG. 10 shows a composite terminal 23 on the data receiving side.
FIG. 9 is a sequence diagram showing exchange of frames with an emphasis on operation at 0. This figure is a figure corresponding to FIG. 4 in the first embodiment.

Note that the symbol "V **" used in this figure means image information to be retransmitted. The initial priorities stored in the transmission priority management unit 80a according to the present embodiment are as shown in the row at times t1 to t3 in FIG. 11, and are the same as the priorities according to the first embodiment. In addition, the type of information to be transmitted and received and the reference interval stored in the delivery confirmation transmission interval management unit 70a are the same as those in the first embodiment.

FIG. 11 is a diagram showing the stored contents (priority) of the transmission priority management unit 80a at each time shown in FIG. 10, and the transmission priority changing unit 80b changes the priority. FIG. Time t1
At t3, the composite terminal 230 performs the same operation as in the first embodiment.

At time t3, two events occur. One is the same as in the first embodiment, and is the generation of a delivery confirmation D (6 *) to be transmitted. That is, the constant interval elapse notification unit 70c notifies the frame determination unit 80 that the count value of the acknowledgment transmission interval measurement unit 70b has reached the reference interval of the acknowledgment transmission interval management unit 70a.

The other is the generation of image information V ** to be retransmitted. That is, it is assumed that the frame received at time t3 includes a request to retransmit the image information of the immediately preceding frame. Therefore, the image information retransmission management unit 71a notifies the frame determination unit 80 that image information to be retransmitted has occurred. In the frame determining unit 80 receiving the above two notifications, first, the transmission priority changing unit 80b changes the priority stored in the transmission priority managing unit 80a based on the notification from the image information retransmission managing unit 71a. I do. Specifically, the priority of the data and the delivery confirmation is lowered by one. As a result, the priorities are as shown in the row from time t3 to time t4 in FIG.

Subsequently, the frame determination unit 80 refers to the type of information to be transmitted (voice information, image information, and acknowledgment) and the priority stored in the transmission priority management unit 80a, and thereby, as shown in FIG. The next transmission frame is determined to have the format b according to the determination flow shown in FIG. The reason why the decision flow of FIG. 8 is adopted is that the priorities obtained by the above change (priorities shown in the rows from time t3 to t4 in FIG. 11) are the times t1 to t5 in FIG. Is the same as the one shown in the row.

As described above, immediately after the time t3, a frame in the format b including the reproduced image information V ** without transmitting the delivery confirmation D (6 *) is transmitted. Time t
In 4, the transmission priority changing unit 80b knows that the image information V ** to be retransmitted has been transmitted, and changes the storage content of the transmission priority managing unit 80a to change the original priority (FIG. 11). (Priority shown in the row from time t4).

The frame determining unit 80 determines that the information to be transmitted is the voice information, the image information, the delivery confirmation D (7 *), and the priority stored in the transmission priority managing unit 80a. The next transmission frame is determined to have the format c according to the determination flow of (1). As a result, at time t5, the frame in the format c including the delivery confirmation D (7 *) prepared by the protocol processing unit 70 immediately before is transmitted to the composite terminal 120.

As described above, according to the present embodiment, a communication device or a communication system provided with the following transmission confirmation transmission timing determination rule is realized.・ If there is image information to be resent that has strong real-time properties,
Raise the priority of the image information to be retransmitted over the data delivery confirmation. That is, according to the third embodiment, the protocol processing unit 71 is provided with the image information retransmission management unit 71a, and the frame determination unit 80
Is provided with a transmission priority changing unit 80b, and when there is image information to be retransmitted, by confirming the delivery of the data or changing the priority of the image information to be retransmitted, the transmission of the data can be efficiently confirmed without losing the real-time property. Can be sent.

In the third embodiment, an image information retransmission management section 71a for notifying that image information to be retransmitted has occurred.
Is provided in the protocol processor 71 for image information, but may be provided in a protocol unit for information other than audio information or audio / image. (Embodiment 4) Next, the composite terminal 1 according to Embodiment 4
40 and 240 will be described.

Composite terminals 140 and 2 according to Embodiment 4
40 is characterized by changing the priority of transmitting the acknowledgment according to the transmission quality of data. FIG. 12 is a functional block diagram illustrating a configuration of the PHS telephone combined terminals 140 and 240 according to the fourth embodiment. The difference from the first embodiment is that a transmission quality notifying unit 70e is added to the protocol processing unit 70 and a transmission priority changing unit 80b is added to the frame determining unit 80. Embodiment 1
10-12, 20-22, 31, 3 in common with
2, 70, 70a to 70c, 80, 80a, 50, 60
The description of is omitted.

The transmission quality notifying section 70e calculates the reception rate of error frames per unit time (transmission error occurrence rate),
It has a function of notifying the frame determination unit 80 of the result as transmission quality. Specifically, by referring to the CRC included in the received frame, it is determined whether a transmission error has occurred in the received frame (whether the frame is an error frame).
Is determined, and the ratio of error frames to all frames received in a unit time is repeatedly calculated as a transmission error occurrence rate.

The transmission priority changing unit 80b has a function of changing the priority stored in the transmission priority management unit 80a according to the transmission quality notified from the transmission quality notifying unit 70e. Specifically, the transmission error occurrence rate notified from the transmission quality notifying section 70e is a threshold "0.001
% ", And if it is larger than the threshold value, the priority of data and delivery confirmation is changed to be one higher than the initial priority, and if smaller, the priority is returned to the initial priority. .

Next, the composite terminal 1 configured as described above
The operation in the case where the communication is performed by 40 and 240 will be described. FIG. 13 shows a composite terminal 24 on the data receiving side.
FIG. 9 is a sequence diagram showing exchange of frames with an emphasis on operation at 0. This figure is a figure corresponding to FIG. 4 in the first embodiment.

The transmission priority management unit 80 according to the present embodiment
The initial priorities stored in “a” in FIG.
This is as shown in the row of t3, which is the same as the priority in the second embodiment. In addition, the type of information to be transmitted and received and the reference interval stored in the delivery confirmation transmission interval management unit 70a are the same as those in the first embodiment. FIG. 14 is a diagram showing the stored contents (priority) of the transmission priority management unit 80a at each time shown in FIG.
It is a figure explaining a mode that a priority is changed by 0b.

At times t1 to t3, the composite terminal 230 operates in the same manner as in the first embodiment. Time t
In 3, two events occur. One is the same as in the first embodiment, and is the generation of a delivery confirmation D (6 *) to be transmitted. That is, the constant interval elapse notification unit 70c notifies the frame determination unit 80 that the count value of the acknowledgment transmission interval measurement unit 70b has reached the reference interval of the acknowledgment transmission interval management unit 70a.

The other is a decrease in transmission quality. In other words, it is assumed that the transmission quality notification unit 70e has notified the frame determination unit 80 of the transmission error occurrence rate "0.1%" because an error has occurred in the frame received up to the time t3. Frame determination unit 80 receiving the above two notifications
, First, the transmission priority change unit 80b transmits the transmission priority management unit 8 based on the notification from the transmission quality notification unit 70e.
The priority stored in 0a is changed. Specifically, the priority of data and delivery confirmation is increased by one. As a result, the priorities are as shown in the row from time t3 to time t4 in FIG.

Subsequently, the frame determining section 80 refers to the type of information to be transmitted (voice information, image information, and acknowledgment) and the priority stored in the transmission priority management section 80a, thereby obtaining the information shown in FIG. The next transmission frame is determined to have the format c according to the determination flow shown in FIG. The reason why the decision flow in FIG. 3 is adopted is that the priority (priority shown in the row from time t3 to t4 in FIG. 14) obtained by the above change is the same as the priority in the first embodiment. .

In this way, at time t4, a frame in format c including delivery confirmation D (6 *) is transmitted. Here, if the transmission quality notifying unit 70e notifies the frame determining unit 80 of the transmission error occurrence rate “0%” because no error has occurred in the frame received until time t3, the transmission priority change Part 80b
Does not change the priority order as described above, and maintains the initial priority order, so that the frame determination unit 80 determines the next transmission frame to be of format b. That is,
The reason why the frame of the format c is transmitted at the time t4 is that the above two events overlap, and the frame including the delivery confirmation is not transmitted if only one of the events occurs.

As a result, when the transmission quality of the received data is reduced, the acknowledgment is returned from the receiving side to the transmitting side little by little, and the acknowledgment is efficiently performed in response to the change in the transmission quality. Is sent. If there is no error in the data D (6) of the frame received at the time t5 and it has passed more than the unit time from the time t3,
The transmission quality notifying unit 70e notifies the frame determining unit 80 of the transmission error occurrence rate “0%”.
b changes the content of the transmission priority management unit 80a to return to the initial priority (priority shown in the line from time t4 in FIG. 14).

As described above, according to the present embodiment, a communication device or a communication system provided with the following transmission acknowledgment determination rule for acknowledgment is realized. -When transmission quality is poor, the priority of transmission confirmation is raised to give priority to transmission and reception of information that does not allow transmission errors. -If the transmission quality is good, the acknowledgment does not need to be sent frequently, so the priority of the acknowledgment is lowered.

That is, according to the fourth embodiment, the transmission quality notifying section 70e is provided in the protocol processing section 70, the transmission priority changing section 80b is provided in the frame determining section 80, and the priority of information to be transmitted is changed according to the transmission quality. By doing
An effective acknowledgment transmission timing corresponding to the state of transmission quality can be determined. The function of detecting the state of transmission quality may be provided in the communication control unit 60.

The transmission quality notifying section 70e may calculate the ratio between the number of error frames received up to that point and the total number of received frames as the transmission error occurrence rate. (Embodiment 5) Next, the composite terminal 1 according to Embodiment 5
50 and 250 will be described.

Composite terminals 150 and 2 according to Embodiment 5
50 changes the transmission interval of the delivery confirmation based on the amount of transmission delay. FIG. 15 is a functional block diagram illustrating a configuration of the PHS telephone composite terminals 150 and 250 according to the fifth embodiment. The difference from the first embodiment is that the protocol processing unit 70 is additionally provided with a delivery confirmation transmission interval changing unit 70f and a transmission delay measuring unit 70g. Components 10 to 12, 20 to 22, and 3 in common with the first embodiment
1, 32, 50, 60, 70, 70a to 70c, 80,
Description of 80a is omitted.

The transmission delay measuring section 70g has a function of measuring data transmission delay. Here, the transmission delay is a time required from transmission of data to reception of a response to the data from a communication partner. Specifically, PH
S Internet access ・ PHS INTERNET ACCESS standardized by Forum Technical Committee
RTF value specified in FORUM STANDARD (PIAFS) 1st edition
Data transmission delay is measured at regular intervals (every minute) according to the (transmission delay) measurement method.

The acknowledgment transmission interval changing section 70f has a function of changing the reference interval stored in the acknowledgment transmission interval management section 70a according to the transmission delay measured by the transmission delay measuring section 70g. Specifically, the delivery confirmation transmission interval changing unit 70f
When the transmission delay is notified from the transmission delay measuring unit 70g, the reference type is changed to a reference interval in which the reference type is "elapsed time" and the reference amount is "half the transmission delay".

Next, the composite terminal 1 configured as described above
The operation when the communication is performed between the 50 and 250 will be described. FIGS. 16A and 16B show the composite terminal 250.
FIG. 16A is a sequence diagram showing the exchange of frames between the composite terminals 150 and 250 when a transmission error has occurred in the delivery confirmation 412 itself transmitted to the complex terminal 150 from FIG. FIG. 16B shows a case before the initial reference interval (reference type “frame”, reference amount “5”) stored in the unit 70a is changed, and FIG. 16B shows a case after the change.

The left time axis 410 corresponds to the operation of the composite terminal 150 that transmitted the data immediately before, and the right time axis 411 corresponds to the operation of the composite terminal 250 that has received the data. Also,
In the present embodiment, only transmission / reception of transmission confirmation is a problem, and transmission / reception of other types of information (audio information, image information) is omitted in FIGS. 16 (a) and 16 (b).

As shown in FIG. 16A, before the initial reference interval stored in the delivery confirmation transmission interval management section 70a is changed, the composite terminal 250 transmits the delivery confirmation 412 transmitted immediately before. After receiving the notification 413 indicating that a transmission error has occurred, the acknowledgment 414 is retransmitted, so that the composite terminal 150 waits for at least the transmission delay before receiving the acknowledgment 414 without error.

On the other hand, as shown in FIG. 16B, after the storage contents of the delivery confirmation transmission interval management section 70a are changed to the reference type "elapsed time" and the reference amount "1/2 of the transmission delay". Since the composite terminal 250 retransmits the delivery confirmation 415 before receiving the notification 413 that the transmission error has occurred in the delivery confirmation 412 transmitted immediately before (time t7),
The composite terminal 150 does not wait for the transmission delay,
Error-free delivery confirmation 41 at an early stage (time t8)
5 can be received.

As described above, according to the fifth embodiment, the data receiving side 250 effectively transmits the acknowledgment based on the measurement result of the transmission delay.
0 enables efficient data transmission. In the fifth embodiment, the transmission interval of the acknowledgment is changed based on the transmission delay measured by the transmission delay measuring unit 70g. However, instead of the transmission delay measuring unit 70g, the transmission quality notifying unit in the fourth embodiment is used. 70e can also be provided. That is, the acknowledgment transmission interval changing unit 70f changes the reference interval stored by the acknowledgment transmission interval management unit 70a according to the transmission quality calculated by the transmission quality notification unit 70e.
This realizes a flexible communication device that can determine an effective delivery confirmation transmission timing corresponding to a changing transmission quality state.

In the first to fifth embodiments, the type of information that does not allow transmission errors is “data”. However, the present invention is not limited to this. "Or" Image information that does not tolerate transmission errors "
Similarly, by effectively expanding the protocol processing units 31 and 32 and the frame determination unit 80, it is possible to effectively transmit audio information and image information.

In the first to fifth embodiments, the composite terminals 110 to 150 and 210 to 250 have input / output units for all of “data”, “audio information” and “image information”. There is no need to have it. That is,
Only the input unit or the output unit may be used. Further, the type of the transmission information need not be “data”, “audio information”, or “image information”. However, at least one of the multiplexed transmission information needs to be information that does not allow a transmission error.

Further, in the first to fifth embodiments of the present invention, the composite terminals 110 to 150 and 210 to 250 are PHS telephones for performing circuit-switching type communication. However, the present invention is limited to circuit switching and PHS telephones. Instead, for example, a packet-switched next-generation communication terminal may be used.

[0099]

As is apparent from the above description, the present invention provides multimedia information including first type information requiring delivery confirmation and second type information different from the first type information. A communication device that multiplexes and transmits and receives in frame units, a fixed period elapse detecting means for detecting that a certain period has elapsed since the last transmission of the acknowledgment, and after the detection has been made, Acknowledgment transmitting means for transmitting a frame including an acknowledgment for the first type information, wherein the acknowledgment transmitting means includes an acknowledgment,
A priority storage unit that stores priority regarding transmission of the type information and the second type information; and a delivery confirmation to be transmitted according to the priority stored in the priority order storage unit. A frame deciding unit that decides at least one frame format and a transmitting unit that transmits a frame according to the decided frame format are provided.

As a result, even when it is necessary to continuously transmit acknowledgments, the acknowledgments are spaced at least for a certain period of time and have priority over other information to be transmitted. Sent in consideration of. Accordingly, a communication device that minimizes a decrease in the transmission efficiency of such information and efficiently transmits a delivery confirmation while considering the characteristics of each information reflected in the priority order is realized.

Here, the certain period may be a period from the last transmission of the acknowledgment until the total number of frames including the first type information among the received frames reaches a certain value. As a result, since one acknowledgment is returned for a group of frames, the frequency of transmitting the acknowledgment is reduced as compared with the case where one acknowledgment is returned for one frame. Is done.

[0102] The predetermined period may be a period from the last transmission of the transmission confirmation to the lapse of a predetermined time. This makes it possible to limit the number of times that the delivery confirmation is transmitted per fixed time, so that it is easy to secure a substantial transmission speed of other information. Also,
The communication device further includes means for measuring a time from when the detection is performed to when a first frame including the delivery confirmation is transmitted, and a priority stored in the priority storage according to the measured time. Means for changing the frame format, and the frame determination unit may determine the frame format according to the changed priority.

Thus, the transmission priority of the transmission confirmation in the normal state is set to be low, and the priority is increased with the elapse of time, so that it is guaranteed that the necessary transmission confirmation is transmitted. The priority of other information that requires real-time performance, such as the normal time, can be made higher in normal times. Also, the multimedia information includes:
A notification requesting retransmission of the second type information is included;
The communication device further includes: a unit configured to detect whether the notification is included in the received frame; and, when it is detected that the notification is included, transmitting the second type information with higher priority. Means for changing the priority order stored in the priority order storage unit, wherein the frame determination unit determines the frame format according to the changed priority order.

Thus, in the case of retransmission due to an error in the image information, the priority can be changed so that the image information is retransmitted prior to the transmission of the acknowledgment. And the deterioration of image quality is suppressed. The communication device may further include: a unit configured to detect a transmission error rate occurring in the received first type information; and a priority stored in the priority storage unit according to the detected transmission error rate. Means for changing the frame format, wherein the frame determination unit determines the frame format according to the changed priority.

As a result, a flexible communication apparatus capable of changing the frequency of transmitting the acknowledgment according to the change in the communication situation is realized. Then, by increasing the transmission priority along with the increase in the transmission error occurrence rate, it becomes possible to secure the substantial transmission speed of the first type information at a certain value or more regardless of the change in the communication condition. Further, the communication device further comprises: means for detecting an occurrence rate of a transmission error occurring in the received first type information; and means for changing the certain period according to the detected transmission error occurrence rate. The period elapse detecting means may detect that the changed fixed period has elapsed.

As a result, the transmission rate of the transmission acknowledgment is reduced along with the increase of the transmission error occurrence rate, so that the substantial transmission speed of the first type information is maintained at a certain value or more regardless of the change of the communication condition. It becomes possible. In addition, the communication device further includes: a unit that measures a transmission delay of the first type information; and a unit that changes the certain period according to the measured transmission delay.
It may be detected that the changed fixed period has elapsed.

Thus, when a transmission error occurs in the transmitted acknowledgment, the fixed period is changed to a shorter time than the transmission delay, so that a correct acknowledgment cannot be obtained unless the user waits for the transmission delay. Is avoided.
Thus, the communication device according to the present invention, in a communication system that transmits and receives data in a limited transmission band in real time, data that does not allow transmission errors, minimizes image and audio quality degradation, Since data delivery confirmation is performed while ensuring real-time performance, the practical value of the multimedia communication device is particularly large.

[Brief description of the drawings]

FIG. 1 is a functional block diagram illustrating a configuration of composite terminals 110 and 210 according to a first embodiment.

FIGS. 2A to 2C are diagrams showing three types of frame formats.

FIG. 3 shows a flow of determining a frame format by a frame determining unit 80.

FIG. 4 is a communication sequence diagram showing exchange of frames with an emphasis on the operation of the composite terminal 210.

FIG. 5 is a functional block diagram illustrating a configuration of the composite terminals 120 and 220 according to the second embodiment.

FIG. 6 is a communication sequence diagram showing exchange of frames with an emphasis on operation in the composite terminal 220.

FIG. 7 is a diagram showing stored contents (priority) of a transmission priority management unit 80a at each time shown in FIG. 6;

8 is a diagram showing a flow of determining a frame format in a priority order shown in a row at times t1 to t5 in FIG. 7;

FIG. 9 is a functional block diagram showing a configuration of the composite terminals 130 and 230 according to the third embodiment.

FIG. 10 is a communication sequence diagram showing exchange of frames with an emphasis on operation in the composite terminal 230.

11 is a diagram showing storage contents (priorities) of a transmission priority management unit 80a at respective times shown in FIG.

FIG. 12 is a composite terminal 140 and 240 according to the fourth embodiment.
FIG. 3 is a functional block diagram showing the configuration of the embodiment.

FIG. 13 is a communication sequence diagram showing exchange of frames with an emphasis on operation in the composite terminal 240.

FIG. 14 is a diagram showing the storage contents (priority) of the transmission priority management unit 80a at each time shown in FIG.

FIG. 15 shows composite terminals 150 and 250 according to the fifth embodiment.
FIG. 3 is a functional block diagram showing the configuration of the embodiment.

FIG. 16 is a communication sequence diagram showing exchange of frames between the composite terminals 150 and 250. FIG. 16 (a)
FIG. 16B shows a case where the initial reference interval (reference type “frame”, reference amount “5”) stored in the delivery confirmation transmission interval management unit 70a is not changed, and FIG. The communication sequence in the case is shown.

FIG. 17 is an external view of a multimedia multiplex communication system according to the present invention and related technology.

FIG. 18 is a functional block diagram showing a configuration of composite terminals 150 and 250 according to the related art.

[Explanation of symbols]

Reference Signs List 10 data input / output unit 11 audio input / output unit 12 image input / output unit 20 data temporary storage unit 21 audio temporary storage unit 22 image temporary storage unit 30, 70 data protocol processing unit 31 audio protocol processing unit 32, 71 Image protocol processing unit 40, 80 Frame determination unit 50 Multiplexing unit 60 Communication control unit 70a Delivery confirmation transmission interval management unit 70b Delivery confirmation transmission interval measurement unit 70c Fixed interval progress notification unit 70d Delivery confirmation transmission delay notification unit 70e Transmission quality notification Unit 70f transmission confirmation transmission interval changing unit 70g transmission delay measuring unit 71a image information retransmission managing unit 80a transmission priority managing unit 80b transmission priority changing unit 100, 110, 120, 130, 140, 150
Data transmitting composite terminal 200, 210, 220, 230, 240, 250
Data transmission side composite terminal 101, 201 Camera 102, 202 Antenna 103, 203 Display screen 104, 204 Speaker 105, 205 Microphone 106 Keypad

Claims (8)

[Claims] 1. First type information requiring a delivery confirmation,
A communication device for multiplexing multimedia information including second type information of a type different from the first type information and transmitting and receiving the frame information in frame units, wherein a certain period of time has passed since the last transmission of an acknowledgment. A predetermined period elapse detecting means for detecting, and a acknowledgment transmitting means for transmitting a frame including an acknowledgment for the already received first type information after the detection is performed, wherein the acknowledgment transmitting means comprises: A priority storage unit for storing the priorities related to the confirmation, the transmission of the first type information and the second type information; and a delivery confirmation, the first type information and the second type of transmission to be transmitted according to the priority stored in the priority storage unit. A frame determination unit that determines a frame format including at least one of two types of information; and transmits a frame according to the determined frame format. Communication apparatus characterized by comprising a that transmission unit. 2. The method according to claim 1, wherein the certain period is a period from the last transmission of the acknowledgment until the total number of frames including the first type information among the received frames reaches a certain value. The communication device according to claim 1. 3. The communication device according to claim 1, wherein the predetermined period is a period from a last transmission of a transmission confirmation to a lapse of a predetermined time. 4. The communication device further comprises: means for measuring a time from when the detection is performed to when the first frame including the delivery confirmation is transmitted, and stored in the priority storage unit according to the measured time. The communication apparatus according to claim 2, further comprising: a unit configured to change a given priority, wherein the frame determination unit determines the frame format in accordance with the changed priority. 5. The multimedia information includes the second information.
A notification that requests retransmission of the type information is included, and the communication device further includes: a unit that detects whether the notification is included in the received frame; and when it is detected that the notification is included, Means for changing the priority order stored in the priority order storage unit so that the second type information is transmitted with higher priority. The frame determination unit determines the frame format according to the changed priority order. The communication device according to claim 2, wherein the communication is performed. 6. The communication apparatus further comprises: means for detecting a rate of occurrence of a transmission error occurring in the received first type information; and stored in the priority storage unit according to the detected rate of transmission error. 4. The communication device according to claim 2, further comprising: means for changing a priority order, wherein the frame determination unit determines the frame format according to the changed priority order. 7. The communication device further comprises: means for detecting a transmission error occurrence rate occurring in the received first type information; and means for changing the certain period according to the detected transmission error occurrence rate. 4. The apparatus according to claim 2, wherein the predetermined period elapse detecting means detects that the changed predetermined period has elapsed.
The communication device as described. 8. The communication device further includes: a unit that measures a transmission delay of the first type information; and a unit that changes the certain period according to the measured transmission delay. 4. The method according to claim 2, wherein the control unit detects that a changed fixed period has elapsed.
The communication device as described.