JPS62199140A - Data transmission system between composite terminal equipments - Google Patents

Abstract

PURPOSE:To cope with instantly to versatile requests to different communication quality by inserting speed information relating to the coding/decoding speed of real time information to a specific control field so as to reduce the load of a communication network. CONSTITUTION:Composite terminal equipments A-D are connected via an optical network 1 and a terminal station A' is connected as one terminal equipment of a terminal station A. In sending real time information, an area consisting of at least one of part or all of sender station address field and a part or all of logical channel field is specified in the header of a frame format as a control field and the speed information relating to the coding or decoding speed of real time information is inserted to the control field. Further, an optical MODEM 17 is essentially constituted by using a photoelectric converter and sends information to a high speed processing section 15 by the optical coupling with the network 1.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a data transmission system between composite terminal devices.

(Prior Art) A composite terminal device is a device that handles both real-time information such as audio and images and non-real-time information related to data processing such as calculation result data.

In recent years, with the advent of this type of multifunction terminal equipment, it has become necessary to transmit both real-time information and non-real-time information via the same communication network. The lower layer protocol control fields of the transmission protocol, such as field, medium access field, and destination address field, are unified, and the contents of the medium access field are used to identify whether the information sent to the communication network is real-time information or non-real-time information. A data transmission system has been adopted that allows real-time information to be sent out over the communication network with priority over other information, allowing for real-time transmission.

(Problem to be solved by the invention) By the way, in the conventional data transmission system, a code/decoder (CO
The encoding speed and decoding speed of DEC> are fixed, but when considering the transmission of real-time information, the encoding speed and decoding speed of C0DEC should be variable for the following reasons. be. That is, from the viewpoint of transmission efficiency, lowering the encoding speed means reducing the amount of data, so the lower the encoding speed, the greater the number of calls that can be made simultaneously on the communication network. In other words,
This will increase transmission efficiency.

Next, from the viewpoint of communication quality, in the case of audio and moving images, lowering the encoding speed results in a decrease in communication quality such as sound quality and image quality.

However, since speech has silent sections, a high encoding speed is not always required.

A similar point can be made regarding images.

That is, for example, in a video conference, the background of a person is usually fixed, and there are also completely still images such as charts. In the currently widely used image encoding method that uses correlation between screens, the amount of information generated in such cases is extremely small compared to moving images.

Therefore, in such cases, even if the encoding speed is reduced, deterioration in image quality is often not a problem.

That is, it can be said that the encoding speed for obtaining a constant quality of real-time information changes depending on the time or the scene.

On the other hand, users' requirements for communication quality vary; for example, some users may be satisfied with a level of quality that allows them to distinguish the same voice, while other users may require high fidelity.

Furthermore, in two-way communication, the same user may request different quality for uplink and downlink.

Therefore, in order to deal with such problems, for example, D S
I (Digital !1pcech Inter
techniques such as poration) have been proposed. However, in order to reduce the load on the communication network, this DSI technology determines that if the input level is below a certain value when encoding audio, it is a silent section and does not generate a transmission frame. Therefore, control of playback of silent sections, etc. becomes complicated. Furthermore, when this DSI technology is applied to moving images, it may cause a temporary loss of horizontal and vertical synchronization of the screen.

Furthermore, even with such SI core technology, it is difficult to meet the aforementioned diverse demands of users. That is,
In order to respond to the diverse demands of users, increase transmission efficiency without interrupting encoding and decoding, and reduce the load on the communication network, the encoding and decoding speeds of C0DEC must be made variable, and Dynamic variable control is required during communication. To do this, information for controlling the C0DEC encoding/decoding speed (hereinafter referred to as "rate information") is incorporated into the transmission frame, and the C0DEC is
In this case, the problem is how to incorporate the speed information into the transmission frame and into which transmission frame.

The problem here is the transmission of real-time information, so it is appropriate to incorporate the speed information into the transmission frame of real-time information, but adding a special field in the header is a waste of overhead. This is undesirable, and if it is incorporated into the information field, complex control will be required to distinguish between real-time information and speed information.

On the other hand, in non-real-time transmission frames, speed information can be transmitted in the information field. However, since a large delay is generally allowed for the transmission of non-real-time information, it is difficult to match the timing with real-time information.

In summary, in conventional data transmission systems, speed information is not incorporated into transmission frames, and even if speed information is transmitted, it is transmitted at the time of call setup using non-real-time information transmission frames as described above. The actual situation is that the encoding/decoding speed of CODEC is not dynamically changed during communication.

As a result, in the past, high encoding and decoding speeds were used even when the amount of information was small, which increased the load on the communication network and forced users to pay more than necessary. Become.

Furthermore, improvements in data transmission systems are desired in order to meet the aforementioned diverse demands of users.

The present invention was made in view of the above-mentioned conventional problems, and its purpose is to incorporate speed information into a transmission frame of real-time information and to dynamically change the encoding/decoding speed of CODEC during communication. The object of the present invention is to provide a data transmission method between multiple terminal devices that can perform the following steps.

(Means for Solving the Problems) The data transmission system between compound terminal devices of the present invention has the following configuration in order to achieve the above object.

That is, the data transmission method between compound terminal devices of the present invention is a data transmission method between compound terminal devices in which a plurality of compound terminal devices that handle both real-time information and non-real-time information communicate via a communication network. When the compound terminal device transmits and receives real-time information using a transmission frame having a header including at least one of a source station address field and a logical channel field, the multifunction terminal device may include part or all of the source station address field. , specifying an area consisting of at least one of part or all of the logical channel field as a control field, and inserting speed information regarding the encoding speed or decoding speed of real-time information into the control field. and speed information decoding means for decoding the speed information inserted into the control field.

(Function) Next, the function of the data transmission method between composite terminal devices of the present invention configured as described above will be explained.

The header of a transmission frame usually has both a source address field and a logical channel field, but the source address field is not required if the transmission is always from a specific compound terminal device or terminal to a specific destination. In addition, if both transmitting and receiving compound terminal devices have a single terminal, the logical channel field can be omitted.

Therefore, the header of a transmission frame to which the present invention is directed includes at least one of a source station address field and a logical channel field. When transmitting and receiving real-time information using such transmission frames, once a call is set up, communication is often one-to-one at the transmitting multifunction terminal device, and in that case, the sending station address Focusing on the fact that the field and the logical channel field are no longer necessary, when the speed information insertion means forms a transmission frame, depending on real-time information related to transmission, part or all of the source station address field,
A region composed of at least one of part or all of the logical channel field is specified as a control field, and a coding speed of real-time information or speed information regarding the coding speed is inserted into the control field.

On the other hand, in the receiving multifunction terminal device, speed information decoding means decodes the speed information inserted into the control field. Here, the decoding speed indicates the decoding speed on the receiving side.

Furthermore, the encoding speed indicates the encoding speed when the receiving side transmits next time, and this is effective when lowering the encoding speed for the purpose of reducing the load on the communication network.

As explained above, according to the data transmission method between composite terminal devices of the present invention, when transmitting and receiving real-time information using a transmission frame having a header including at least one field among a source address field and a logical channel field, A field consisting of at least one of a part or all of the source station address field and a part or all of the logical channel field is specified as a control field, and a real-time information encoding rate is set in the control field. Alternatively, by inserting speed information regarding the decoding speed, the following various excellent effects can be obtained.

That is, firstly, when the amount of information generated is small, the load on the communication network can be reduced, and the cost of using the communication network for users can be reduced. Second, it is possible to immediately respond to various demands for communication quality that differ from user to user. Thirdly, since the encoding/decoding speed of CODEC can be controlled in accordance with the timing of the information being sent or sent, it is superior to the method of sending control signals in transmission frames of non-real-time information. In addition, since the transmission of speed information uses a field that is always required in the real-time information transmission frame, there is no increase in overhead and the communication network is used efficiently.Fourthly, this method uses the DSI Since it does not interrupt transmission like other technologies, there is no problem with playing back silent sections or maintaining synchronization.
In a system where the end stations of the communication network or a special monitoring station can monitor the traffic on the communication network, when calls are concentrated and the call loss rate increases, some or all of the end stations may have to reduce the encoding speed. The present invention also makes it possible to reduce the call loss rate by lowering the call loss rate, and to transmit emergency information without interrupting other calls when traffic is saturated.

As described above, according to the present invention, great effects can be expected for communication networks and terminal stations connected to communication networks.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1st
The figure is a configuration block diagram of a data transmission method between composite terminal devices according to an embodiment of the present invention, in which a plurality of composite terminal devices (terminal stations A, B, C5 and D) are connected to a high-speed optical network 1.
The figure shows a case where terminal station A' is connected as one terminal of terminal station A.

The high-speed optical network 1 is a transmission line network made of optical fibers, and the network shape is arbitrary, such as a star shape or a loop shape. Each compound terminal device has approximately the same configuration as exemplified as terminal station A and terminal station A, and has a computer workstation 2 as an input/output device for non-real-time information, and a television as an input device for real-time information (images). The computer workstation 2 is equipped with a camera 3, a monitor television 4 as an output device for real-time information (images), and a telephone 5 as an input/output device for real-time information (audio). Camera 3, Monitor TV 4, and Telephone 5
are respectively connected to a system bus 10 which is centrally controlled by a CPU 9 via a code/decoder (CODEC) 7 and a parallel/serial converter (PS) 8.

A memory 11, a programmable counter 12, and a speed conversion buffer 13 are also connected to the system bus 10.

Further, the speed conversion buffer 13 is connected to a high speed processing section 15 via a bus 14, and the high speed processing section 15 is connected to an optical modem 17 via a bus 16. Note that the terminal station A' is branch-connected to the bus 14 of the terminal station A. Here, the transmission information sent out and transmitted on the high-speed optical network 1 is in the form of a transmission frame of a predetermined format.

For example, as shown in FIG. 2, this transmission frame includes a header 21 for transmission control, an information field 22 into which transmission information is inserted, and a trailer (with or without) 23 for error control, etc. It consists of The header 21 also includes a synchronization control field 211, a medium access field 212 for priority control, a destination address field 213, and a source address field 214.
and a logical channel field 215 for specifying a terminal connected to the originating and terminating station.

The content of the medium access field 212 determines whether the transmitted information is real-time information or non-real-time information, that is, whether the transmitted frame is a real-time frame or a non-real-time frame. As mentioned above.

Further, in this type of transmission frame, the structure of the header 21 and the length of each part vary depending on the communication network protocol, but are usually unified in the same communication network.

By the way, the synchronization control field 211 in the header 21
The medium access field 212 and the destination address field 213 are necessary regardless of whether the transmitted information is real-time information or non-real-time information; however, in the transmission of real-time information, the originating station address field 2
As mentioned above, the logical channel field 215 and the logical channel field 215 are not always required.The present invention focuses on this point.

That is, in the present invention, a frame for transmitting non-real-time information has a format as illustrated in FIG. A region consisting of at least one of part or all of the field 215 is specified as a control field, and speed information regarding the encoding speed or decoding speed of real-time information is inserted into the control field. , the speed information insertion means decodes the speed information inserted into the control field and transmits the output information of the high speed processing unit 15 to the high speed optical network 1 by optical coupling with the high speed optical network 1. The transmission information is transmitted to the high-speed processing section 15.

The high-speed processing unit 15 matches the transmission information in a predetermined transmission frame format output by the speed conversion buffer 13 with the communication speed on the high-speed optical network 1, and also matches the transmission information input via the optical modem 17 to its own station. This high-speed processing unit 15 performs processing to match it to the speed that can be internally processed.
Then, each component of the header 21 is encoded and decoded. Speed conversion buffer 13 is under the control of CPU 9 and provides timing control between system bus 10 and bus 14, since the data rate on system bus 10 is slower than on bus 14. The programmable counter 12 has an oscillator O8C,
Generates a clock at a predetermined speed according to instructions from the CPU 9,
Connect it to the clock input terminal CLK IN of C0DEC7.
It is output to. The C0DEC7 encodes or decodes real-time information based on the clock.

That is, real-time information from the television camera 3 and telephone 5 is encoded and sent in the form of serial data from the output terminal SO to the PS8, and from the PS8 to the input terminal SI.
It decodes the serial data output to and outputs it to a monitor television 4 and a telephone 5. The CPU 9 performs transmission and reception operations of transmission information by controlling the interface conversion adapter 6, PS 8, memory 11, and speed conversion buffer 13. That is, in the transmission operation, data is transmitted from the computer workstation 2 via the interface conversion adapter 6. Non-real-time information and C0D
Real-time information encoded by EC7 from the television camera 3 and telephone 5 is respectively taken out via the PS8 and stored in the memory 11, and a transmission frame is formed in the memory 11. At this time, for real-time information, the control field is formed in the header of the transmission frame, and speed information is inserted therein (operation of speed information insertion means), and the form of the transmission frame formed in this way is For example, there are various types as shown in FIGS. 3 and 4, and the explanation will be given later. Then, the real-time information and non-real-time information are transmitted in the form of respective transmission frames from the memory 11 to the high-speed processing unit 15 via the speed conversion buffer 13, and are sent to the high-speed optical network 1 as transmission transmission information.

On the other hand, in the reception operation, reception information transmitted from the high-speed processing unit 15 to the speed conversion buffer 15 is stored in the memory 11,
The memory 11 decomposes the transmission frame and decodes the speed information inserted into the control field (operation of speed information decoding means), and non-real time information is sent to the computer workstation 2 via the interface conversion adapter 6. . Further, when the decoded speed information is related to the decoding speed, for example, a command is issued to the programmable counter 12 to generate a predetermined clock giving the decoding speed, and the received real-time information is
It is transmitted to CODEC7 via S8. As a result, C0
The DEC 7 decodes the real-time information at a decoding speed based on a predetermined clock and outputs it to the monitor television 4 and telephone 5. On the other hand, if the decoded speed information relates to the encoding speed, the programmable counter 12 is controlled in the next transmission operation to generate a predetermined clock that provides the encoding speed.

Next, a specific example of the transmission frame according to the present invention will be explained.

Figure 3 shows an example of the configuration of a transmission frame, and Figure 3 (A)
In FIG. 3(A), FIG. 3(A) shows a non-real-time frame, and FIG. 3(B) shows a real-time frame.
This non-real-time frame has the same structure as that shown in FIG. 2, with the trailer 23 serving as an error control field.

In addition, in FIG. 3(B), this real-time frame consists of a header 31 and a real-time information field 32, and the header 31 has a speed information field 33 which is the control field at the position of the source station address field 214 of the non-real-time frame. This is provided.

In the case of this real-time frame, there is a logical channel field 215, so it is not limited to one-to-one communication, and when one terminating station has multiple real-time information terminals, the terminating station can accommodate multiple calls at the same time. It is possible to do so.

FIG. 4 shows another example of the structure of the transmission frame.

In FIG. 4(A), this non-real-time frame has the same structure as the first embodiment, with a header 21 provided with a sequential number field, and a trailer 23 consisting of a delimiter, a frame check field, and a flag. be done. In addition, in FIG. 4(B), this real-time frame is composed of a header 41, a real-time information field 42, and a trailer 43 consisting of a frame check field, similar to the non-real-time frame. The header 41 according to the embodiment includes the entire source address field 214 of the non-real-time frame and the logical channel field 215.
A speed information field 44 is provided at a part of the position, and a logical channel field 45 is left in a shortened form.

This shortened logical channel field 45 only needs to have the number of bits sufficient to identify the number of terminals connected to one terminal station, as described above.

Next, FIGS. 5 and 6 show details of the speed information fields 32 and 44.

In FIG. 5, this speed information field includes a code/decode bit 51, a speed change point pointer field 52,
It consists of a speed selection field 53. Here, the speed change point pointer field 52 indicates from which point on the time axis the decoding speed of the information included in the real-time information field in the received frame is to be changed, or from which point on the time axis the encoding speed is to be changed. This is a pointer to The speed selection field 53 is a field for instructing how to actually change the speed.

Further, the code/decode bit 51 is a bit that indicates whether the operation of the speed change point pointer field 52 is related to the coding speed or the decoding speed. Furthermore, the fact that it is a code bit defines the encoding speed for the next transmission by the receiving side.

Note that the arrangement order and length of the code/decode bit 51, speed change point pointer field 52, and speed selection field 53 are arbitrary. Note that when using a real-time frame with a speed information field in this format, a non-real-time frame may be used for call setup.

Also, in FIG. 6, this speed information field is composed of a control bit 61 and an interwoven vector 62. Here, the interwoven vector 62 is interrupt information for the CPU 9 that controls the encoding/decoding speed of the C0DEC7, as shown in FIG.
9 directly controls the encoding/decoding speed of CODEC7.

This interrupt method is effective when the control of the CODEC7 is routine. Also, the control bit 61 indicates whether the next field is a speed information field or a calling station address field, that is, the same structure as a non-real-time frame.By adding this control bit 61, for example, when setting up a call, The same structure as the non-real-time frame can be used, but during communication it can be a rate information field. Furthermore, the processing amount of the control circuit can be reduced by not always providing speed information even during communication. Furthermore, this control bit can also be used as an interwoven trigger.

(Effects of the Invention) As described in detail above, according to the data transmission method between composite terminal devices of the present invention, real-time When transmitting and receiving information, an area consisting of at least one of a part or all of the source station address field and a part or all of the logical channel field is specified as a control field, and the control field is Since speed information regarding the encoding speed or decoding speed of real-time information is inserted, the following various excellent effects can be obtained.

That is, firstly, when the amount of information generated is small, the load on the communication network can be reduced, and the cost of using the communication network for users can be reduced.

Second, it is possible to immediately respond to requests for communication quality that differ from user to user. Third, since the encoding/decoding speed of CODEC can be controlled in accordance with the timing of the information being sent or sent, it is superior to a system in which control signals are sent in transmission frames for non-real-time information. In addition, since the transmission of speed information uses a field that is always required in the real-time information transmission frame, there is no increase in overhead and the communication network is used efficiently.Fourthly, this method uses DSI technology. Since this method does not interrupt transmission, there are no problems with reproducing silent sections or maintaining synchronization.

Fifth, in a system where the end stations of the communication network or a special monitoring station can monitor the traffic on the communication network, when calls are concentrated and the call loss rate increases, some or all of the end stations may The present invention also makes it possible to lower the call loss rate by lowering the encoding speed, and to transmit emergency information without interrupting other calls when traffic is saturated.

As described above, according to the present invention, great effects can be expected for communication networks and terminal stations connected to communication networks.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the configuration of a data transmission system for a composite terminal device according to an embodiment of the present invention, FIG. 2 is a diagram showing the general configuration of a transmission frame, and FIG. 3 is an illustration of a transmission frame according to the present invention. FIG. 4 is a diagram showing another example of the structure of a transmission frame according to the present invention. FIG. 5 is a diagram showing an example of the speed information field. FIG. 6 is a diagram showing an example of the speed information field. It is a figure which shows another example of a structure. 1...High-speed optical network, 2. Old computer tower guest, 3... Television camera, 4... Monitor TV, 5. Old telephone. 7... Code decoder (CODEC), 8...
...Serial-to-parallel converter (ps), 9.Old...cPU,
11... Memory, 13... Speed conversion buffer, 15... High speed processing unit, 17...
...Optical modem, 32.44...Speed information field, A, A', B, C, D...Terminal office (complex terminal device) agent Patent attorney Yoshihiro Yawata 1 to Frey - Ma Rido Pavilion 2 Figures (A) (B) Yi Yun (, Frame /) Blade (I row (1) 3rd Figure 71 of the A frame 144 Figure 11 Yushu 1-Lead 0 groove example (I) Figure 5 Figure C

Claims (1)

[Claims] A data transmission method between multiple terminal devices in which a plurality of compound terminal devices that handle both real-time information and non-real-time information communicate via a communication network; When transmitting and receiving real-time information using a transmission frame having a header that includes at least one of the fields, at least one of a part or all of the source address field and a part or all of the logical channel field. A speed information insertion means for specifying an area constituted by a control field as a control field and inserting speed information regarding an encoding speed or a decoding speed of real-time information into the control field, and a speed for decoding the speed information inserted into the control field. A data transmission method between composite terminal devices, characterized by comprising information decoding means.