JPH09162834A - Communication method and device for changing dynamically compression system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dynamically select or change the system of the sound compression according to the use of the band of a trunk line, to effectively use the line and to reduce a call loss in a synchronous multiplex or asynchronous. multiplex device (including a device having exchange function). SOLUTION: When the use of the line is more than the threshold 406, a connected call is switched to the system of a lower necessary band. Switch permission attributes are previously set in respective calls and the switch permission call is selected as a switch object 410. On a call-side and an incoming-side, resources necessary for the compression system to be switched are secured 412 and 422. When the securing of the resources succeeds, data is transmitted between the connected resource and the newly secured new connection resource. The resource used in existing connection is released after synchronization 420 and 432.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication method and apparatus including voice data, and more particularly to a communication method and apparatus for dynamically changing a compression method. More specifically, a communication device that handles synchronous or asynchronous voice has multiple voice compression methods, which are dynamically selected regardless of an already connected call or a generated call to dynamically change the trunk line usage efficiency. The present invention relates to a communication system and a device optimized for.

[0002]

2. Description of the Related Art A dedicated line is used as a trunk of a conventional time division multiplexer (TDM).
It has been designed to reduce the bandwidth of the trunk lines used by performing voice compression, thereby increasing the number of lines that can be accommodated. There are many voice compression methods, and the method is selected according to the compression rate and voice quality. In the present circumstances,
Hereinafter, the audio compression method is considered as the option. If PCM transmission without compression is also described, compression method Communication speed Compression rate Compression effect scale Voice quality 1. PCM 64 Kb / s 1 1.0 1.0 2. ADPCM 32 Kb / s 2 0.5 0.8 3. LDCELP 16 Kb / s 4 0.25 0.7 4. VSELP 8 Kb / s 8 0.125 0.6 is common.

However, in the prior art, the voice compression method is selected for each call, so that When setting up a voice line, it is necessary to consider the empty capacity of the trunk, determine the optimum compression method, and secure the required bandwidth. 2. After the trunk is empty, the line cannot be secured for the call request and call loss occurs. 3. If the line is used only with a high compression method, the voice quality is always poor and the user cannot be satisfied. The problem occurs.

Japanese Unexamined Patent Publication No. 62-160899 discloses a time-division voice compression system in which a plurality of voice compression systems can be selected.
A trunk selection method is disclosed in which a trunk with a higher speech quality (compression method) is used when a selected speech quality (compression method) trunk is already in use. However, the trunk selection method is a method for selecting one of a plurality of voice compression qualities for an outgoing call, and by dynamically reconnecting an already connected call, the voice compression quality is switched and the bandwidth of the line is effectively used. It is not possible to avoid loss of calls for outgoing calls. Further, after the trunk is empty, the line cannot be secured for the call request, and the above problem that the call is lost cannot be solved.

JP-A-62-143531 discloses a composite communication system including voice information, data information and frame information, in which the communication capacity of voice information, the communication capacity of data information and the communication capacity of frame information are maximum channel capacities. As described above, the communication method for setting the compression ratio of voice information is disclosed.
There is no description suggesting dynamic reconnection of already connected calls, and if all trunks are already in use due to the compression method with high speech quality, the voice compression quality is switched and effective use of the bandwidth of the line and call loss for outgoing calls It is impossible to avoid.

[0006]

SUMMARY OF THE INVENTION According to the present invention, by dynamically reconnecting an already connected call, the voice compression quality is switched, the line usage efficiency of the trunk is dynamically optimized, and a call for an outgoing call is made. The purpose is to avoid losses.

[0007]

[Means for Solving the Problems] As long as the bandwidth of the trunk permits, a compression method with high voice quality is used, and when the bandwidth is insufficient or when a predetermined threshold is reached, the already established line is connected. On the other hand, switching to a method with a high compression rate secures the bandwidth for newly generated call requests. In addition,
In order to facilitate understanding of the present invention, the description of the present invention will be limited to audio data, but the idea of the present invention includes text data, image data, etc. in addition to audio data. Also in the transmission method, not only the time division multiplexing method but also the frequency division method, the code multiplexing method, the method combining the time division multiplexing method and the frequency division method, and the like can be used. It can also be used for wireless communication and optical communication. Further, not only a synchronous multiplexer such as TDM but also an ATM which can have a switching function
The present invention can also be applied to an asynchronous multiplexing device that performs packet multiplexing or cell multiplexing.

The communication device of the present invention, in response to the request for changing the compression ratio, newly connects the call at a compression ratio different from that of the currently connected call, and the current connection in the newly connected call. Communicating the same data as the call being made. Here, in response to the request for changing the compression rate of the present invention, the step of newly connecting a call at a compression rate different from that of the currently connected call includes the step of newly connecting after disconnecting the currently connected call. It includes both the step of connecting a call and the step of connecting a new call in parallel with the currently connected call.

According to another aspect of the present invention, the medium, in response to the compression rate change request, instructs the communication device to newly connect a call with a compression rate different from that of the currently connected call. The program code means, the program code means for instructing the communication device to communicate the same data as the currently connected call in the newly connected call, and the resources used in the currently connected call are released. A program code means for instructing the communication device to do so and a program means for controlling the communication device for communication at two or more different compression rates are stored.

According to another aspect of the present invention, a communication method includes a step of inspecting a current line usage amount and a first connection currently made when the current line usage amount reaches a predetermined range. Selecting a call having a compression rate of 1, a step of determining whether a call having a second compression rate can be newly connected, and a call having a second compression rate when it is determined that the call can be connected. , A step of connecting the same data as the call of the first compression rate in the call of the second compression rate, and a step of disconnecting the call of the first compression rate.

According to another aspect of the present invention, there is provided a communication method, wherein a call is made at the first terminal, a call is detected, a current line usage is checked, and a current line is used. When the usage amount reaches a predetermined range, a step of selecting a currently connected call of the first compression rate at the second terminal, and a caller newly calling at the second compression rate Check the resource management table to see if the DSP channel, trunk band and interconnect band required to connect the call can be secured, and request the callee to secure a resource to connect the call at the second compression rate. At the stage of issuing, at the step of detecting the resource securing notification from the called side, and at the calling side, it is determined that connection is possible, and when the resource securing notification is detected,
The steps of connecting the call at the second compression rate, performing the same data communication as the call of the first compression rate in the call of the second compression rate, and establishing the synchronization in the call of the second compression rate. The steps include performing and disconnecting the call with the first compression ratio and releasing the DSP channel, trunk band, and interconnect band used in the call with the first compression ratio. This terminal is a concept including a terminal device, a telephone, and a FAX.

According to another aspect of the present invention, there is provided a communication method, wherein when the current line usage amount is smaller than the first threshold value, the second line is used.
Is set as a compression rate having a required bandwidth larger than the first compression rate, and the second compression rate is set when the current line usage is larger than the second threshold which is a value larger than the first threshold. Can be set to a compression rate with a required bandwidth smaller than the first compression rate.

According to another aspect of the present invention, in a communication method, a step of selecting a call having a first compression rate is performed such that an attribute allowing a compression rate of a call having a first compression rate is higher than a second compression rate. Can also be conditioned to have a high value.

A communication method, which is another aspect of the present invention, includes a voice band for performing voice communication with a time division multiplexer, a data band for performing data communication, and control information of another time division multiplexer. A step of allocating a band to a supervisory control channel for communication and inspecting the current line usage amount, a step of inspecting the number of lines in the data band, and selecting a currently connected call having the first compression rate. Can be selected as the currently connected voice band line.

The communication device of the present invention, in response to the request for changing the compression rate, has means for newly connecting the call with a compression rate different from that of the currently connected call, and the current connection in the newly connected call. Means for communicating the same data as the call being made. Here, in response to the compression rate change request of the present invention, the means for newly connecting a call at a compression rate different from that of the currently connected call is newly connected after disconnecting the currently connected call. It includes both means for connecting a call and means for connecting a new call in parallel with the currently connected call.

According to another aspect of the present invention, there is provided a communication system for inspecting a current line usage amount, and a first connection currently made when the current line usage amount reaches a predetermined range. Means for selecting a call with a compression rate of 2, and a means for determining whether a call with a second compression rate can be newly connected, and if it is determined that a call with a second compression rate can be connected, a call with a second compression rate is made. For connecting the same data as the call of the first compression rate in the call of the second compression rate, and a means of disconnecting the call of the first compression rate.

According to another aspect of the present invention, there is provided a communication system in which a first terminal for making a call, a terminal interface for detecting the call, and means for checking the current line usage amount,
If the current line usage reaches a predetermined range,
A means for selecting a currently connected call of the first compression rate in the second terminal, a DSP channel, a trunk band and an interconnect required for newly connecting the call in the second compression rate at the calling side. Means for inspecting the resource management table to ensure bandwidth, means for issuing a resource reservation request to the callee for connecting the call at the second compression ratio, means for detecting a resource reservation notification from the callee , The calling side determines that the connection is possible, and when the resource securing notification is detected, means for connecting the call at the second compression rate, and the means for connecting the call at the second compression rate Means for transmitting the same data as the call, means for establishing synchronization in the second compression rate call,
It includes a resource management mechanism including means for disconnecting the call of the first compression rate and releasing the DSP channel, trunk band and interconnect band used in the call of the first compression rate.

According to the present invention, when the current line usage amount is smaller than the first threshold value, the second compression ratio is set to a compression ratio having a required bandwidth larger than the first compression ratio, and the current line usage amount is When the second compression ratio is larger than the second threshold, which is a value larger than the first threshold, the second compression ratio can be a compression ratio having a smaller required band than the first compression ratio.

The present invention provides for the step of selecting a call with a first compression ratio, provided that the attribute allowing the compression ratio for the call with the first compression ratio has a higher value than the second compression ratio. can do.

According to the present invention, the time division multiplexing apparatus provides a voice band for voice communication, a data band for data communication, and a supervisory control channel for communicating control information with other time division multiplexing apparatus. The means for allocating a band and checking the current line usage also checks the number of lines in the data band and selects the currently connected first compression rate call.
It is possible to select a currently connected voice band line.

The time division multiplexing apparatus according to another aspect of the present invention secures resources necessary for newly connecting a call at a compression rate different from that of the currently connected call, which is transmitted from the calling side. It is determined that the request can be secured, the means for detecting the request, the means for responding to the resource securing request, and the means for checking whether or not the resource necessary for newly connecting the call at the second compression rate can be secured. In this case, the means for sending the resource reservation notification to the calling side, the means for connecting the call at a compression rate different from that of the currently connected call, and the currently connected call at the compression rate different from that of the currently connected call Means for receiving the same data as the existing call.

A communication system according to another aspect of the present invention is
A means for checking the current line usage, a means for selecting a currently connected call having a first compression rate when the current line usage reaches a predetermined range, and a first compression rate Means for transmitting from the calling side to the called side a signal notifying that the call is changed to a call with the second compression rate, a means for disconnecting the call with the first compression rate, and a second compression rate And a means for connecting a call with a call, the disconnection of the call having the first compression rate and the connection of the call having the second compression rate at the calling side and the called side are performed by the line delay between the calling side and the called side. And the real-time clock time difference between the calling side and the called side.

[0023]

FIG. 1 is a diagram showing an embodiment of a communication system 100 according to the present invention. The communication system 100 includes a time division multiplexer 2 and is connected to each other by a high speed digital line 6 and an ISDN 8.
A PBX 4 and a HOST computer 10 are connected to the time division multiplexing device 2, and a terminal device 14, a telephone 16 and an FA are connected.
X18 is connected directly or via PBX4. The LAN 12 connects the terminal device 14 to the router 20.
It is connected to the time division multiplexer 2 via.

FIG. 8 is a block diagram showing an embodiment of the communication apparatus of the present invention. Terminal connection interface (Terminal I
/ F) 206 is a data terminal 14, a voice terminal 16, an FA
The X18 or the like is electrically connected to perform call detection, incoming notification, data flow control, disconnection detection, and the like. Implementation by optical communication or wireless communication is an alternative means that can be easily performed by those skilled in the art. Interconnect 204
Is composed of a BUS or a switch, and in the first embodiment of the present invention, it is required that one-to-one and one-to-many connections can be made. The trunk line interface (trunk I / F) 202 controls a line connecting the communication devices 210. In the time division multiplexer, the connection of each terminal is logically or physically multiplexed and placed on one trunk line.

The voice compression mechanism 208 comprises one or a plurality of signal processing units (DSP) and can process the required number of voice channels. The audio compression method to be executed can be selected for each channel. FIG. 11 shows a specific configuration of the voice compression mechanism 208. As shown in FIG. 11, the DSP has a plurality of channels. In the figure, the DSP 242
Channel 252 of is connected to connection a,
The transmission rate of 16 Kb / s is compressed. Also, D
Channel 256 of SP244 is unused.

The resource management mechanism 210 responds to the connection request of the voice call generated from the terminal connection interface by the resource of the voice compression mechanism 208 (DSP channel), the resource of the trunk line (trunk line band) and the resource of the interconnect 204 (interconnect band). ) Is assigned to each resource, and the connection is completed by defining the relation of each resource on the resource management table 212 as a physical route for this call connection. Further, the resource management information is exchanged with the resource management mechanism on the opposite communication device 214, and mutual confirmation of necessary resource securing is performed. The resource management mechanism 210 includes an MPU 210, a memory 218, a control channel 216, and a control program 212. The control program is diskette, MO, CD-R
It is stored in a medium such as an OM or a hard disk device and can be loaded into the memory 218.

The memory 218 is a resource management table 2
12 inclusive. A conceptual diagram of the resource management table 212 is shown in FIG. The resource management table 212 includes a terminal interface 222, a trunk interface 224, a voice compression mechanism (DSP) for each connection.
Channel) 226 interconnect 228 manages channel information of each resource. Here, a connection is a concept like a pipe that a user runs end-to-end. On the other hand, a channel has a meaning as a unit in which each resource is assigned to a connection. The resource management table can be configured by hardware such as switch means.

FIG. 9 is a block diagram of the resource management mechanism 210 of the present invention. The resource management mechanism 210 includes a central processing unit (CPU) 301 and a memory 304. CP
The U 301 and the memory 304 are connected to a hard disk device 306 as an auxiliary storage device via a bus 302. Floppy disk drive (or MO, CD-
A diskette 318 is inserted into a drive device 317 such as a ROM, and the diskette (or MO, CD-RO) is inserted.
A medium such as M) 318 or the hard disk device 306,
The computer program code for implementing the present invention in the communication system 100 is recorded. The resource management mechanism 210 may be a system further including user interface hardware, and the user interface hardware may be, for example, a pointing device (mouse) 32 for inputting.
2 to a keyboard 320 and a display 312 for presenting visual data to the user. The resource management mechanism 210 can be replaced by a personal computer or a workstation.

Next, a preferred embodiment (first embodiment) of the communication method of the present invention will be described with reference to FIG. Calling side terminal (terminal device 14, telephone 16 or FAX 1
8 is included) (block 402), the calling terminal interface 206 causes the resource management mechanism 21
0 is notified of call detection (block 404). In response to this notification, the resource management mechanism 210 responds to the line usage (B
u) is checked to determine whether to switch compression methods (block 406). The present invention dynamically allocates different types of data as shown in FIG. 12, that is, when the voice data increases, the number of voice bands is increased and the number of data bands is decreased. Is increased, the number of voice bands is decreased and the number of data bands is increased. In such cases,
It is possible to switch the compression rate in the data band for the voice call, and to switch the compression rate in the voice band for the general data call. Then, by checking the total line usage of different types of data or by checking the line usage of limited plural types of data, it is possible to determine whether or not to switch.

The condition for switching the compression method is that a threshold value (Bth) is set for the bandwidth usage amount (Bu) of the trunk line, and the relationship between the threshold value and the actual usage amount is the condition for switching the voice compression method. Examples of switching conditions at this time are shown in FIGS.
This will be described below. 2 has a transmission rate of 1.5 Mb / s according to the leased line service contract J1, so that 24 channels can be transmitted when transmitting by PCM (1.5 Mb / s = 1536 Kb / s). s, 1.5Mb
/ S ÷ 64 Kb / s = 24). Similarly, ADP
When the CM is used for transmission, 48 channels can be transmitted (1.5 Mb / s ÷ 32 Kb / s = 48).
Here, the threshold value is Bth = 1.5 Mb / s−32K
If b / s = 1,504 Kb / s is set, a compression method with a small required bandwidth is used when the usage of the line is equal to or more than the threshold (Bu> = Bth).

At this time, by switching the already connected call to a system having a lower required band, it is possible to give the trunk a band margin for accommodating a newly generated call. This procedure will be described later. When it is determined that the voice compression method is not switched, that is, when the usage of the line is less than the threshold value (Bu <Bth), the connection with the called party is performed by the conventional call connection procedure. (Block 408). When it is determined to switch the audio compression method, that is, when the line usage is equal to or more than a threshold value (Bu> = Bth)
Selects an already connected call for which the dynamic compression method is to be switched (block 410).

As a condition for selecting an already connected call for which the dynamic compression method is to be switched, selection is made according to the elapsed time after connection, that is, an old connection completion is selected as a switching target (condition 1), and a switching permission attribute is used. It is conceivable that selection, that is, a switching permission attribute is set in advance for each call, and a call for which the switching permission attribute is set is selected as a switching target (condition 2) or a combination thereof. It is preferable that the condition 1 and the condition 2 are determined by prioritizing the condition 2. This switching permission attribute can be realized by giving an attribute to each terminal (call type) at the time of network configuration and registering a flag indicating whether switching is permitted in the attribute management table. By using multiple bits of this flag, for example, "11" cannot be compressed.
10 "allows compression up to 32 Kb / s," 01 "is 16
It is also possible to set compression to Kb / s, "00" to compression up to 8 Kb / s, and to allow all compression methods when there is no corresponding terminal number in the table.
For example, the compression permission table can be set as follows: call type permission attribute summary 0001 01 outside line 1 0003 11 FAX1 0055 10 trunk line 1 0066 00 trunk line 2.

This permission attribute not only inspects the calling side, but also notifies the terminal number of the called side via a supervisory control channel or the like, and the resource management mechanism of the called side makes the resource management table of the called side. By checking the permission attribute of the callee terminal using the callee terminal number as a key, and notifying the callee permission attribute to the caller resource management mechanism. It is possible to select an already connected call to which the dynamic compression method is to be switched, on the condition that the permission attributes of both callers are conditions. That is, when the calling side permission attribute is "00" and the called side permission attribute is "01", 2
The two attributes are compared, and the larger value (01) is determined as the condition. This value is compared with the current voice compression value in the resource management table, and the current voice compression value is 32K.
If it is a numerical value indicating b / s (provided that the compression method switching of the present invention is changed to a compression rate with a low one-stage audio quality), Condition 2 can be cleared. In other words, it can be determined by the inequality of permission attribute (16 Kb / s) <current compression rate (32 Kb / s) managed in the resource management table. With such an attribute management method, it is possible to connect a call having a quality according to the content of data to be transmitted. This attribute permission table can be made to exist in the memory.

In this way, after the selection of the already connected call to be switched (block 410), the resource management mechanism 210 on the calling side has the resources required for the compression method to be switched.
The DSP channel, trunk band, and interconnect band are reserved (block 412).

When the compression switching method is a method for switching the current compression method to the compression method having the next poorer voice quality,
That is, the PCM transmission method is changed to the ADPCM transmission method
DPCM transmission method to LDCELP transmission method, LDCE
If the LP transmission method is converted to the VSELP transmission method, it is confirmed that there is a resource capable of connecting the call of the communication method to be switched.

This switching method is the same as the current compression method.
It is also possible to switch to a compression method with inferior voice quality, in which case the PCM transmission method is LDCE.
The LP transmission method and the ADPCM transmission method are converted to the VSELP transmission method. In addition, PCM transmission system, ADPCM
Converting all transmission methods and LDCELP transmission methods to VSELP transmission methods, PCM transmission methods, ADPCM
It is also possible to convert the transmission method to the LDCELP transmission method and the LDCELP transmission method to the VSELP transmission method by changing the control program of the resource management mechanism. The method of converting all the transmission methods into the VSELP transmission method makes it possible to set the threshold to the minimum (8 kbps). It is also possible to permit the user to change the control program of the resource management mechanism. As a method that can be changed by this user, for example, the following table is created, and the compression method can be selected according to this table. Connected call 1st choice 2nd choice 11 10 01 10 01 where "11" is 64 Kb / s and "10" is 32 Kb / s
s, "01" is switched to 16 Kb / s, "00" is switched to 8 Kb / s, and when there is no registration, switching is performed to 8 Kb / s.

In this table, there is a second choice, which is, for example, 64 when explained in the matter registered in the first line of the table.
When switching the compression method of an already connected call of Kb / s,
First, it is judged whether or not resources for newly connecting a 32 Kb / s call can be secured, and if so, a new 32 Kb / s call is connected. However, if the resource cannot be secured, the resource management mechanism next judges whether or not the resource for newly connecting the 16 Kb / s call can be secured, and if the resource can be secured, , 16 Kb / s to establish a new call connection.

Returning to FIG. 13 again. If the resources cannot be secured, the call of block 402 can be processed as a call loss, and the compression rate switching process of the present invention is stopped. Further, in parallel with the step of checking the line usage in block 406, it is possible to compress and connect the call originated in block 402. This procedure will be described later. At the same time as this resource reservation, the resource management mechanism 210 on the calling side requests the resource management mechanism on the called side to reserve the resource (block 412). The exchange of control information between the calling side and the called side is generally performed via a supervisory control channel (service channel).

On the other hand, the resource management mechanism on the called side secures resources (block 422). If the resource is successfully secured, a confirmation notification that the resource has been secured is sent to the calling side, and if the resource is not secured, a notification that the resource has not been secured is sent to the calling side (block 424). In this case, after a certain period of time,
It is also effective to perform the resource securing process again or to repeat the resource securing process a certain number of times. In such a case, the resource released due to the termination of communication by another channel can be effectively used. The calling side receives the notification from the called side and waits for a certain time until the secured notification is sent (block 414). If the securement notification is not sent within a certain period of time, it is determined as a call loss and block 40
The second call can be processed, and the compression rate switching process of the present invention is stopped. Also, the call of block 402 can be treated as a call loss by the first notification of unavailability. Furthermore, the arrival of the resource reservation notice can be repeatedly checked a fixed number of times.

In block 414, if the caller's resource reservation notice is confirmed, the caller's connection processing is performed (block 416). In the first embodiment of the present invention, the caller's connection process is executed. In the interconnect, the voice data from the terminal side interface is multicast to both the already connected resource and the newly secured newly connected resource. That is, the same data communication is performed on the two channels. Then, on the calling side, the DSP channel performs compression and puts it on each logical trunk line.

On the other hand, the DSP channel of the new connection resource on the called side synchronizes the frame containing the compressed data (block 426). Specifically, this is achieved by examining the header portion and / or trailer portion of the audio frame. Then, after synchronization, decompression is executed.
Thereafter, connection processing is performed 428 at the called party. Specifically, this is achieved by the called-side resource management mechanism connecting the DSP channel to the connection-side interface card after confirming that synchronization has been achieved or after the elapse of a predetermined time required for synchronization. If frame synchronization is detected on the called side, the calling side is notified of the synchronization being successful, and if not successful, the calling side is notified that the synchronization was not possible (block 430). In this case, if synchronization is not detected within a certain period of time, processing is performed as a time-out, and a notification that synchronization could not be performed is given.

Thereafter, when frame synchronization is detected on the called side, the DSP channel used for the existing connection is disconnected and released 432 together with the resources on the trunk side.
On the other hand, the calling side waits for a certain period of time until it receives the notification from the called side and sends the synchronized notification (block 418). If the securement notification is not transmitted even after the elapse of a certain period of time, it is determined that the timeout has occurred, the call of block 402 can be processed as a call loss, and the compression rate switching process of the present invention is stopped. Similarly,
If the out-of-sync notification is received, the call at block 402 may be treated as a lost call. After that, when the calling side determines that the synchronization is established, the unnecessary resource generated by the dynamic compression mode switching is registered in the resource management table as an empty resource and assigned 420 to the newly generated call.
The resource manager 210 then allocates 408 new resources to the pending outgoing call.

In this method, a new connection is newly set for an already connected call, the old connection is disconnected and its resources are released. Therefore, when switching the compression method, noise that may affect a call is generated. Occurrence can be avoided. However, since the dual connection method is temporarily adopted, the interconnect unit needs a one-to-many connection function.

Next, the procedure for switching the already connected call of the present invention to a compression method having a different required band will be described with reference to FIGS. 2 to 4. In FIG. 2, the channel 106 is unused and the channel 104 and the channels 110 to 11 are used.
4 is used. It is assumed that the communication capacity of each channel is 32 Kb / s and that transmission is performed by the ADPCM compression method. This state is Bu = Bth =
When the next call originates, the already-connected call is switched to a system with a lower required band according to the present invention. The resource management mechanism 210 detects this state of Bu = Bth and selects the already connected call to be switched. The selected connection call is channel 104.

A conceptual diagram of the communication state of the channel 104 is shown in FIG. In FIG. 5, the time-division multiplexer 1 on the calling side
32 transmits voice data to the called-side time division multiplexer 134 via the channel 104, and exchanges control information via the supervisory control channel 140. next,
The resource management mechanism on the calling side secures the resources required for the switching compression method. It is assumed that the channel 108 shown in FIG. 3 is secured. In this channel 108, the same data communication as in the channel 104 is performed. FIG. 6 is a conceptual diagram of this state. Thereafter, when the frame synchronization of the transmission on the channel 108 is confirmed, the channel 104 is disconnected and the resources used by the channel 104 are released. FIG. 7 is a conceptual diagram of this state. Therefore, the channel 104 shown in FIG. 3 becomes an empty channel and is assigned to a newly generated call.

Next, another embodiment (second embodiment) of the present invention will be described with reference to FIGS. 3 and 4 in which the compression method has a voice quality higher than that of the currently connected call.
In FIG. 3, it is assumed that the channels 104 and 112 are unused and the channels 108, 110 and 113 to 114 are used. Channels 108 and 110 have a communication capacity of 16 Kb
/ S, transmission is performed by the LDCELP compression method. It is assumed that the other channels are transmitted by the ADPCM compression method (32 Kb / s). The lower threshold is Bth2 = 1,472 Kb / s (1.5 Mb /
s-64 Kb / s). In the second embodiment of the present invention, as in the case of the first embodiment of the present invention, the terminal interface detects a call from the terminal so that the line usage is not checked but the terminal usage is checked. It is preferable that the interface detect the disconnection of the call and check the line usage. When the line usage amount is checked, the line usage amount Bu and the lower threshold Bth2 are compared, and when Bu <= Bth2, that is, it is determined that the line is idler than a predetermined value. In this case, the compression method switching according to the second embodiment of the present invention is performed. When the resource management mechanism 210 decides to perform the switching, it selects the already connected call to be the switching target. The selected connection call is channel 108.

A conceptual diagram of the communication state of this channel 108 corresponds to FIG. Next, the resource management mechanism on the calling side or the called side secures the resources necessary for the switching compression method. In the flowchart of FIG. 13, in the second embodiment, either the calling side or the called side can take the initiative. Further, in block 406, since it can be confirmed that the call can be connected by the new compression method, blocks 410, 412, 414, 422, 424 are used.
The processing for securing resources on the calling side and the called side of is not essential.

It is assumed that it has been decided to transmit the call of the new compression method through the channel 104 shown in FIG. In this channel 104, the same data communication as in channel 108 is performed. FIG. 6 is a conceptual diagram of this state. Thereafter, when the frame synchronization of the transmission on the channel 104 is confirmed, the channel 108 is disconnected and the channel 10 is disconnected.
The resources used in 8 are released. FIG. 5 is a conceptual diagram of this state. Therefore, the channel 108 shown in FIG. 3 becomes an empty channel and is assigned to a newly generated call.

Next, a preferred embodiment (third embodiment) of the communication method of the present invention will be described with reference to FIG. Similar to the first embodiment, the calling terminal 14 and the telephone 1
6 or FAX 18 when a call is made (block 50
2) The calling terminal interface 206 notifies the resource management mechanism 210 of the detection of the call (block 50).
4). When it is determined to switch the voice compression method, that is, when the line usage is equal to or more than a threshold (Bu>
= Bth), an already connected call to which the dynamic compression method is switched is selected (block 510). After the switching target connected call is selected, the resource management mechanism 210 on the calling side secures the resources required for the switching compression method (block 512). If the resource cannot be secured, the same processing as in the first embodiment is performed. Then, as in the first embodiment, the resource management mechanism 210 requests the called-side resource management mechanism to secure the same resource (block 512). In response, the called party resource management mechanism secures resources (block 522). If the resources are secured, the confirmation notification that the resources have been secured is made, and if the resources are not secured, the notification that the resources have not been secured is sent to the calling side (block 52).
4).

When it is confirmed in block 514 that the called party has secured the resource, the switching time is notified from the calling side to the called side, unlike the first embodiment of the present invention (block 516). . The called party confirms this notification, and if there is no notification, the call of block number 502 can be treated as a call loss (block 526).
The calling side notifies the called side of the switching time,
The calling side disconnects the already connected call (block 518), releases the resources used in the already connected call (block 520), and performs the call connection processing by the new compression method on the calling side. This (block 52
1). That is, the calling side transmits only the new connection resource newly secured with the voice data from the terminal side interface in the interconnect. Then, on the calling side, the DSP channel performs compression and puts it on each logical trunk line. In the first embodiment of the present invention,
One-to-one and one-to-many connections are required, but in the second embodiment of the present invention, one-to-many connections are not required.

Disconnection of the already connected call between the calling side and the called side,
In the series of processing of releasing the resources used in the already connected call and connecting the call by the new compression method, if there is a time lag in switching, noise will occur and the call quality will deteriorate, so it will not affect the actual call. It is desirable to be on time. For this reason, in the improved third embodiment of the present invention, the real time clocks of the calling side and the called side are used to perform switching by designating the time.

In the following description of the improved third embodiment of the present invention, it is assumed that the time required for each switching process and the latency required for its activation are known and taken into consideration in each time calculation. Also, within the time that does not affect the voice quality during the actual call, the synchronization error to be realized is
It is desirable to be 10 ms or less.

In order to switch the call between the calling side and the called side at the same time, it is necessary to obtain the line delay between the calling side and the called side and the real time clock time difference between the calling side and the called side. Becomes The line delay between the calling side and the called side is measured by measuring the time required for loopback connection to an adjacent node, sending a delay measurement packet, and receiving the packet.
2. Calculate one-way time (time Tld)
It can be obtained by The real-time clock time difference between the calling side and the called side is from the calling side to the called side, or
The calling side notifies the called side of the time (Tr) and Tld of the real-time clock of its own node by a time difference measurement packet. The receiving node compares the time of the real time clock of its own node with Tr + Tld and calculates the time difference (Ts). Return Ts to the requesting node.

Upon receiving the compression system change notification, the connecting entity determines the switching absolute time (Tcs), that is, the absolute time at which switching is performed in the real-time clock of the calling side, and determines the switching absolute time of the other side. The switching request packet is used. However, such a procedure is a procedure in which the calling side and the called side perform switching at the same time, so that the time difference between them is checked, and there are many alternatives that can be easily conceived by those skilled in the art. For example,
Before the method of the present invention operates, the time difference between the two is checked in advance, the value is stored, and switching is performed based on the value, or the time difference between the two is obtained not at the calling side but at the called side. And so on.

On the other hand, after receiving the notification of the switching time to the called side, the called side disconnects the connected call (block 528) and releases the resources used in the connected call (block 528). Block 530), call connection processing by the new compression method will be performed (block 532). In this case, the disconnection of the already connected call in blocks 518 and 528, the resource release of the already connected call in blocks 520 and 530, and the connection processing of the call by the new compression method in blocks 521 and 532 may be performed first. , If the connection processing of the call by the new compression method is performed after disconnecting the already connected call and releasing the resources of the already connected call, the resources released by the already connected call are used for the connection of the call by the new compression method. Because you can, block 5
The processing for securing resources on the calling side and the called side of 10, 512, 514, 522, 524 is not essential (when switching to a compression method with low voice quality). However, if the connection processing of the call by the new compression method is performed after disconnecting the already connected call and releasing the resources of the already connected call, it takes time to reconnect after disconnecting the already connected call. Voice quality may be affected. The new call generated in block 502 may be connected immediately after the call is detected in block 504 or may be connected by the conventional call connection procedure in block 508.

[0056]

As described above, according to the present invention,
It is possible to effectively select or change the compression method depending on the usage rate of the bandwidth of the trunk line in the synchronous multiplex or asynchronous multiplex device (including the one having the switching function), and to effectively use the line. Reduction can be realized. In other words, when setting up a line, not only secure the required bandwidth by considering the empty capacity of the trunk and determine the optimal compression method, but also secure the line for the call request even after the trunk is empty. It is possible to prevent the occurrence of call loss. In addition, it is possible to connect a call of appropriate quality by simultaneously considering the usage status of the line and the content of the data to be transmitted.

[0057]

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a communication system of the present invention.

FIG. 2 is a conceptual diagram of a conventional audio frame.

FIG. 3 is a conceptual diagram of a voice frame for explaining the present invention.

FIG. 4 is a conceptual diagram of a voice frame for explaining the present invention.

FIG. 5 is a conceptual diagram for explaining a communication system of the present invention.

FIG. 6 is a conceptual diagram for explaining a communication system of the present invention.

FIG. 7 is a conceptual diagram for explaining a communication system of the present invention.

FIG. 8 is a block diagram of a communication device that is an embodiment of the present invention.

FIG. 9 is a block diagram of an embodiment of a resource management mechanism of the present invention.

FIG. 10 is a block diagram of an embodiment of a resource management table of the present invention.

FIG. 11 is a block diagram of an embodiment of a voice compression mechanism of the present invention.

FIG. 12 is a conceptual diagram showing allocation of bands between TDMs.

FIG. 13 is a flowchart showing an embodiment of the communication method of the present invention.

FIG. 14 is a flowchart showing an embodiment of the communication method of the present invention.

[0058]

[Explanation of Codes] 100 communication system 2 time division multiplexer 4 PBX 6 high speed digital line 8 ISDN 10 HOST computer 12 LAN 14 terminal device 16 telephone 18 FAX 20 router 202 trunk interface 204 interconnect 206 terminal interface 208 voice compression mechanism 210 Resource management mechanism 212 Resource management table

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhisa Yoshimura 1623 Shimotsuruma, Yamato-shi, Kanagawa 14 Japan AIBM Co., Ltd. Yamato Works (72) Inventor Ryoji Takahashi 1623 Shimotsuruma, Yamato-shi, Kanagawa Address 14 Japan AIBM Co., Ltd. Yamato Works

Claims (16)

[Claims] 1. A method of communicating at two or more different compression rates, comprising the steps of: (a) inspecting the current line usage, and (b) the current line usage reaches a predetermined range. In this case, the step of selecting a currently connected call having the first compression rate, (c) the step of determining whether a call having the second compression rate can be newly connected, and (d) the step ( If it is determined in c) that the call can be connected, the step of connecting the call at the second compression rate is the same as the call of the first compression rate in the call of the second compression rate. A method comprising: communicating data; and (f) disconnecting the call at the first compression rate. 2. A communication method in a communication system, comprising at least a first terminal and a second terminal connected to each other, comprising a voice compression mechanism and a time division multiplexing apparatus for performing communication at two or more different compression ratios. a) making a call at the first terminal; (b) detecting the call; (c) checking the current line usage; (d) the current line usage When a predetermined range is reached, a step of selecting a call having the first compression rate that is currently connected in the second terminal, and (e) a second compression rate is newly set at the calling side. In the step of inspecting the resource management table for whether the DSP channel, the trunk band and the interconnect band necessary for connecting the call can be secured, and (f) the call is connected to the called side at the second compression rate. The step of issuing a resource securing request for ( g) detecting a resource reservation notice from the called side, and (h) at the calling side, when the resource reservation notice is detected and it is determined that connection is possible, the second compression rate is used. Connecting the call, (i) communicating the same data as the call with the first compression rate in the call with the second compression rate, and (j) synchronizing with the call with the second compression rate. And a step of: (k) disconnecting the call having the first compression rate and releasing the DSP channel, the trunk band, and the interconnect band used in the call having the first compression rate. . 3. If the current line usage is smaller than a first threshold value, the second compression ratio is a compression ratio having a required bandwidth larger than the first compression ratio, and the current line When the usage amount is larger than a second threshold value which is a value larger than the first threshold value, the second compression ratio is a compression ratio having a required band smaller than that of the first compression ratio. The method according to claim 1 or 2. 4. The step of selecting calls of the first compression ratio comprises:
The method according to claim 1 or 2, wherein the attribute allowing the compression rate in the call having the first compression rate has a value higher than that of the second compression rate. 5. The time division multiplexing device is a band for a voice band for voice communication, a data band for data communication, and a supervisory control channel for communication of control information with another time division multiplexing device. And the step of inspecting the current line usage also inspects the number of lines in the data band,
3. The method of claim 1 or 2, wherein the step of selecting a currently connected first compression rate call selects a currently connected voice band line. 6. A method of communicating at two or more different compression rates, the step of: (a) responding to a request to change the compression rate and connecting a new call at a compression rate different from that of the currently connected call. And (b) communicating the same data in the newly connected call as in the currently connected call. 7. A medium for storing a program for controlling a communication device for communication at two or more different compression rates, said program being (a) currently connected in response to a compression rate change request. Program code means for instructing the communication device to connect a new call at a compression rate different from that of the existing call, and (b) the same data as the currently connected call in the newly connected call. A medium including: program code means for instructing the communication device to perform communication; and (c) program code means for instructing the communication device to release the resources used in the currently connected call. 8. A communication system comprising at least a first terminal and a second terminal connected to each other, comprising a voice compression mechanism and a time division multiplexing device for performing communication at two or more different compression ratios. (B) a means for selecting a currently connected call having a first compression rate when the current line usage reaches a predetermined range; ) Means for determining whether a call having a second compression rate can be newly connected, and (d) When the means (c) determines that a call can be newly connected, the second compression rate is used. Means for connecting the call, (e) means for communicating the same data as the call with the first compression rate in the call with the second compression rate, and (f) disconnecting the call with the first compression rate. A system including: 9. A communication system comprising at least a first terminal and a second terminal connected to each other, comprising a voice compression mechanism and a time division multiplexing apparatus for performing communication at two or more different compression ratios. A first terminal for making a call, (b) a terminal interface for detecting the call origination, (c) a resource management mechanism including the following means, and (c-1) means for checking the current line usage (C-2) means for selecting a currently connected call at the first compression rate in the second terminal when the current line usage amount reaches a predetermined range, (c-3) A means for inspecting the resource management table whether the calling side can secure the DSP channel, the trunk band and the interconnect band necessary for newly connecting the call at the second compression rate, (c-4) In contrast,
A means for issuing a resource reservation request for connecting a call at the second compression ratio, (c-5) a means for detecting a resource reservation notification from a called side, and (c-6) a calling side for connection. When it is determined that the resource reservation notification is possible, the means for connecting the call at the second compression rate, (c-7) the first compression rate of the call at the second compression rate Means for transmitting the same data as the call, (c-8) means for establishing synchronization in the call with the second compression rate, (c-9) disconnecting the call with the first compression rate, and A communication system including means for releasing a DSP channel, a trunk band and an interconnect band used in a call having a compression rate. 10. If the current line usage amount is smaller than a first threshold value, the second compression ratio is a compression ratio having a required bandwidth larger than the first compression ratio, and the current line ratio is smaller than the first compression ratio. When the usage amount is larger than a second threshold value which is a value larger than the first threshold value, the second compression ratio is a compression ratio having a required band smaller than that of the first compression ratio. The communication system according to claim 8 or 9. 11. The step of selecting a call of the first compression rate is conditional on that the attribute allowing the compression rate of the call of the first compression rate has a higher value than the second compression rate. The communication system according to claim 8 or 9, wherein 12. The time division multiplexing device is a band for a voice band for voice communication, a data band for data communication, and a supervisory control channel for communicating control information with another time division multiplexing device. The means for inspecting the current line usage also inspects the number of lines in the data band, and the means for selecting the currently connected first compression rate call is currently connected. 10. The communication system according to claim 8 or 9, wherein a line of a voice band in which it is present is selected. 13. A device for communicating at two or more different compression ratios, (a) means for newly connecting a call at a compression ratio different from that of a currently connected call in response to a request to change the compression ratio. And (b) means for communicating the same data in the newly connected call as in the currently connected call. 14. A time division multiplexing apparatus that performs communication at two or more different compression rates, and (a) newly connects a call at a compression rate different from that of a currently connected call transmitted from a calling side. Means for detecting a resource securing request necessary to secure a call, and (b) a means for responding to the resource securing request and checking whether a resource necessary for newly connecting a call at the second compression rate can be secured. And (c) means for transmitting a resource reservation notice to the calling side when it is determined that the call can be secured, and (d) means for connecting the call at a compression rate different from that of the currently connected call. And (e) means for receiving the same data as the currently connected call in a call having a compression rate different from that of the currently connected call. 15. A communication system comprising at least a first terminal and a second terminal, comprising a voice compression mechanism, and a time division multiplexing device capable of performing communication at two or more different compression ratios. a) means for inspecting the current line usage, and (b) means for selecting a currently connected call with the first compression rate when the current line usage reaches a predetermined range. (C) means for transmitting a signal notifying that the call of the first compression rate is changed to a call of the second compression rate from the calling side to the called side, (d) the first compression Rate disconnecting means, and (e) connecting the call at the second compression rate. 16. (d-1) Disconnecting a call having a first compression ratio and connecting a call having a second compression ratio between the calling side and the called side are performed by the calling side and the called side. 16. The system according to claim 15, wherein the system is executed with a time difference of a line delay between them and a real time clock time difference between a calling side and a called side.