JP3402261B2 - Tone connection system using ATM switch - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ATM (Asynchrono
Tone connection system using us Transfer Mode switch, especially tone to connect tone signal to subscriber terminal corresponding to each type of ATM cell or type of voice coding rule via ATM switch It relates to the connection system.

[0002]

2. Description of the Related Art A conventional example of a tone signal connection system using such an ATM switch will be described with reference to FIG. In FIG. 14, when sending various tone signals such as a busy tone and a ring back tone via the ATM switch 11 to the subscriber terminal 16 capable of receiving the PCM signal, the PCM signal sound source 21 is required.
When the tone signal is sent to the terminal 18 capable of receiving (Adaptive Differential PCM) signal via the ATM switch 11, the ADPCM signal sound source 22 is required. In this way, sound sources are required for each type of speech coding rule.

When an ATM cell of AAL (ATM Adaptation Layer) type 2 is used to improve the transmission efficiency of a voice signal by the ATM cell, a sound source 23 for transmitting the ATM cell of AAL type 2 is further required. Becomes
That is, CS-ACELP (Conjugate Structure an
When a tone signal is sent to the subscriber terminal 20 capable of receiving d Algebraic Code-Excited Linear Prediction) signals via the ATM switch 11, a sound source 23 compatible with AAL type 2 is required.

In FIG. 14, 15 and 17 are AALs.
ATM-STM (Synchronous Transfer M) for type 1
ode) converter, tone PC from sound sources 21 and 22
The SAL conversion is performed on the AAL type 1 ATM cell of the M signal. 19 is ATM-S for AAL type 2
This is a TM converter, which performs STM conversion of AAL type 2 ATM cells of the tone PCM signal from the sound source 23.

[0005]

As described above, the conventional technique shown in FIG. 14 requires a sound source for a tone signal in accordance with the type of voice coding rule and the ATM cell type, and the resource is reduced. However, there is a drawback in that

Japanese Unexamined Patent Application Publication No. 10-262051 discloses a technique in which a single sound source is used for tone signals. However, in this technique, subscriber terminals are limited to one type. Therefore, as shown in FIG. 14, it does not correspond to the subscriber terminal according to the type of the voice coding rule or the ATM cell type.

An object of the present invention is to classify speech coding rules and A
It is an object of the present invention to provide a tone connection system using an ATM switch that can reduce the number of sound sources by standardizing the sound sources required for the AL type.

[0008]

According to the present invention, an ATM
A tone connection system for connecting a tone signal to a subscriber terminal corresponding to a cell type type or a voice coding type type via an ATM switch, wherein a PCM signal of the tone signal is set to a predetermined value. Tone signal generation means for outputting as a cell of one ATM type type, and tone cell-converted tone PC from the tone signal generation means
Voice coding rule conversion means for converting the M signal according to the voice coding rule, type classification conversion means for converting the ATM type classification of the ATM cellized tone PCM signal into another type classification, and the subscriber terminal In response to the tone signal connection request from the subscriber terminal, the voice coding rule conversion means and the type classification conversion means are selectively controlled by the ATM switch according to the type classification and the voice coding rule of the subscriber terminal. And a control means for converting the tone signal from the tone signal generating means into a tone signal corresponding to the subscriber terminal and supplying the tone signal.

The control means has a database in which specific information is stored in advance in order to specify the corresponding type type and the corresponding voice coding rule type of each of the subscriber terminals. In response to the tone signal connection request, the correspondence specifying information of the subscriber terminal is read from the database, and the ATM switch controls the selection of the voice coding rule converting means or the type classification converting means in accordance with the specifying information. It is characterized by doing so.

Further, the control means sets control information according to the specific information in a header of the ATM cellized signal, and the selection control is performed by this control information. The control information is an identifier for identifying a connection in the header.

When the subscriber terminal is compatible with PCM, the control means controls the tone P converted into the ATM cell.
The CM signal is controlled so as to be supplied to the subscriber terminal through the ATM switch without passing through the voice coding rule conversion means and the type classification conversion means, and the subscriber terminal is ADPCM. In the case of correspondence, the control means causes the tone PCM signal converted into the ATM cell to be converted into the ATM switch, the voice coding rule conversion means,
The ATM switch is controlled so as to be supplied to the subscriber terminal through this order.

Further, the subscriber terminal is a CS-ACELP.
In the case of correspondence, the control means causes the tone PCM signal converted into the ATM cells to pass through the ATM switch, the voice coding rule conversion means, the ATM switch, the type classification conversion means, and the ATM switch in this order. It is characterized in that it is controlled so as to be supplied to the subscriber terminal.

The operation of the present invention will be described. A voice codec (coding rule converter) and an AAL converter (type type converter) are connected to the ATM switch, and in response to a tone signal connection request from the subscriber terminal, the type type and voice code of this subscriber terminal are connected. According to the law, a voice codec and an AAL converter are selectively controlled by an ATM switch to convert a tone signal from a sound source into a tone signal corresponding to a subscriber terminal and supply the tone signal.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system configuration diagram of an embodiment of the present invention, and the same portions as those in FIG. 14 are designated by the same reference numerals. In FIG. 1, the sound source 12 is an ATM switch 1
1 is connected to various tones from the sound source 12
CM (Pulse Code Modulation) signal for AAL type 1
It is assumed that the data is transmitted in the form of being converted into the ATM cell.

The ATM switch 11 includes an AAL converter 1
3 and audio codec 14 are connected, and AA
ATM-STM converters 15 and 17 for L1 and A for AAL2
The TM-STM converter 19 is connected. AAL1
Each of the ATM-STM converters 15 and 17 for PCM has a PCM
A subscriber terminal 16 for ADPCM and a subscriber terminal 18 for ADPCM are respectively connected. A CS-ACELP subscriber terminal 20 is connected to the AAL2 ATM-STM converter 19.

Reference numeral 21 denotes a control unit, which responds to a tone signal request from a subscriber terminal that has passed through the ATM switch 11 and identifies which type of terminal this subscriber terminal is. The specific information set in advance is read out from the database 22 and the tone signal of the sound source 12 is ATM.
The control information for that purpose is set in the cell header.

Here, as shown in FIG. 2, when a tone is sent to the subscriber terminal 16 that can receive a PCM signal, for example,
The sound source 12 generates an ATM cell of an PCM signal of AAL type 1, and the ATM switch 11 uses the ATM cell for AAL1.
-STM converter 15 is switched. This ATM
-In the STM converter 15, the tone is PCM of STM.
It is converted into a signal and sent to the subscriber terminal 16.

Details of the operation of the system in this case will be described with reference to the operation flow of FIG. First, in response to a tone request from the subscriber terminal 16 (step S1), the control unit 2
In step 1, the database 22 is searched for the specific information indicating the voice coding rule or AAL type required by the subscriber terminal 16 (step S2). Based on this search result, the control unit 21 determines whether the ATM cell from the sound source 12 needs to pass through the voice codec 14 or the AAL changer 13, and the VPI (Virtual Path Identifie) of the cell header portion is determined.
r) and VCI (Virtual Channel Identifier) connection identifiers are set to predetermined values, respectively.

In this example, the subscriber terminal 16 is a PC
Since it is for M, the voice codec 14 and the AAL converter 1
3 need not be passed, and the ATM cell from the sound source 12 may be directly switched to the ATM-STM converter 15 for AAL1 as it is. Therefore, each value of VPI and VCI is used as control information for designating the switching state. It is set (step S3). In addition, VPI and VC
Since each I is assigned a capacity of 8 bits (1 byte), it goes without saying that there are 2 16 combinations of values that can be set as 16 bits as a whole.

The ATM cell having these VPI and VCI values set in the cell header is sent to the ATM switch 11 (step S4), and ATM cell switching is performed in the ATM switch 11 to directly perform ATM-STM.
It is sent to the converter 15 (step S5). The converter 15 converts the STM signal into an STM PCM signal (step S6) and sends it to the subscriber terminal 16 (step S7).

Next, as shown in FIG. 4, when a tone is transmitted to the subscriber terminal 18 capable of receiving an ADPCM signal, the tone generator 12 converts the dial tone into a PCM signal into an AAL type 1 ATM cell. The converted data is sent to the ATM switch 11. Here, when the subscriber terminal 18 tries to make a call and needs a dial tone, the ATM switch 11 switches the ATM cell from the sound source 12 to the voice codec 14. With the voice codec 14,
Converts dial tone of PCM signal to ADPCM dial tone, and makes ATM cell of AAL type 1 and AT
It is sent to the M switch 11.

In the ATM switch 11, the ATM cell from the voice codec 14 is transferred to the ATM-STM for AAL1.
Switching to converter 17. ATM-S for AAL1
The TM converter 17 converts the ATM cell into an STM signal and the dial tone ADPCM signal into the subscriber terminal 18.
Send to. At the subscriber terminal 18, the ADPCM signal can be converted into a dial tone of an analog signal and the subscriber can hear the dial tone.

Details of the operation of the system in this case are shown in FIG.
The operation flow of No. 6 will be described. First, the subscriber terminal 1
In response to the tone request from step S8 (step S11), the control unit 21 searches the database 22 for the specific information indicating the voice coding rule and the AAL type required by the subscriber terminal 18 (step S12). Based on this search result, the control unit 21 determines whether or not the ATM cell from the sound source 12 needs to pass through the voice codec 14 or the AAL changer 13, and the VPI and VCI connection identifiers of the cell header part are determined in advance. The respective values are set (step S13). In this example, since it is necessary to pass the voice codec 14, VPI and VCI are set to predetermined values as the control information to that effect.

Thereafter, the ATM cell from the sound source 12 is sent to the ATM switch 11 (step S14).
The ATM switch 11 performs switching to the voice codec 14 (step S15), and the voice codec 14 sets the voice coding rules to V PI and VCI.
Judgment is made from each of the values, and conversion to ADPCM is performed (step S16).

The conversion processing operation of the audio codec 14 in this case is as shown in the flow chart of FIG. That is, A
In response to the AL type 1 cell reception (step S7
1), the signal is converted into a 64 Kbps PCM signal (step S72), and the signal conversion is performed according to the voice compression law according to the subscriber terminal (step S73). Then, ATM cells are formed (step S74), and cells are transmitted (step S75).

Returning to FIG. 6, the ATM-ST for AAL1 is judged from the values of VPI and VCI of the cell header.
Since the cell needs to be switched to the M converter 17, VPI and V need to be switched to the converter 17.
Each value of CI is rewritten (step S17) and sent to the ATM switch 11 (step S18). In the ATM switch 11, the cell is switched to the converter 17 according to each value of VPI and VCI (step S1).
9). The converter 17 converts the signal into an STM ADPCM signal (step S20) and sends it to the subscriber terminal 18 (step S21).

Next, as shown in FIG. 8, for example, a subscriber terminal 2 capable of receiving a signal whose voice coding rule is CS-ACELP.
When sending a tone to 0, the sound source 12 sends out an ATM cell of an PCM signal of AAL type 1 and the ATM switch 11 switches the voice cell to the voice codec 14. The voice codec 14 sends the ATM cell of AAL type 1 of CS-ACELP. Converted to cell.

The ATM cell is A by the ATM switch 11.
It is switched to the AL converter 13, and the AAL converter 13 converts the AAL type 1 to the AAL type 2 ATM cell. Here, the reason for converting to AAL type 2 is that CS-ACELP has a high compression rate and has a low bit rate, so that it is better to use ATM cells of AAL type 2 in a single ATM cell together with other voice signals. This is because the transmission efficiency can be improved. The ATM
The cell is ATM switch 11 and ATM-STM for AAL2.
The converter 19 is switched. Here the tone is ST
The subscriber terminal 20 is converted into the CS-ACELP signal of the M.
Sent to.

Details of the operation of the system in this case are shown in FIG.
This will be described using the operation flow of No. 11. First, in response to a tone request from the subscriber terminal 20 (step S10)
1) In the control unit 21, the database 22 is searched for the specific information indicating the voice coding rule and the AAL type required by the subscriber terminal 20 (step S102). Based on this search result, the control unit 21 determines whether or not the ATM cell from the sound source 12 needs to pass through the voice codec 14 and the AAL changer 13, and the VPI and V of the cell header portion are determined.
Each of the CI connection identifiers is set to a predetermined value (step S103). In this example, since it is necessary to pass the voice codec 14 and the AAL converter 13, VPI and V are used as the control information.
CI is set to each predetermined value.

Thereafter, the ATM cell from the sound source 12 is sent to the ATM switch 11 (step S10).
4). Voice codec 1 in ATM switch 11
4 is performed (step S105), and the voice codec 14 determines the voice encoding rule from each value of VPI and VCI and converts it into CS-ACELP (step S106). The conversion processing operation of the audio codec 14 in this case is as shown in the flow of FIG.

Since it is necessary to switch the cell to the AAL converter 13 by judging from the respective values of VPI and VCI of the cell header, the respective values of VPI and VCI are rewritten so as to be switched to the converter 13 ( Step S1
07), and is sent to the ATM switch 11 (step S
108). In ATM switch 11, VPI and V
The cell is switched to the AAL converter 13 according to each value of CI (step S109). This converter 13 converts the ATM cell of AAL1 into the ATM cell of AAL2 (step S110).

An example of this AAL type conversion processing will be briefly described with reference to FIGS. 12
(A) is an AAL type 1 ATM cell format, and (B) is an AAL type 2 ATM cell format. When converting from the former type to the latter type, FIG.
As shown in, it is possible to divide the user information in the AAL type into user information of the short cell of the AAL type 2 and transfer the data.

Returning again to the flow of FIG. 11, the converter 13
Then, each value of VPI and VCI is rewritten so that the cell is switched to the ATM-STM converter 19 for AAL2 (step S111), and the ATM cell is sent to the ATM switch 11 (step S112). Then, at the ATM switch 11, ATM-S for AAL2
The cells are switched to the TM converter 19 (step S
113), STM CS-ACEL in this converter 19
It is converted into a P signal (step S114). In this way, the tone is transmitted to the subscriber terminal 20 (step S115).

[0034]

As described above, according to the present invention,
Tones can be sent to the subscriber without depending on the type of voice coding rule that the subscriber can receive and the type of AAL type of the ATM cell. The effect that there is no need to prepare a sound source separately is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a system according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining the operation of one embodiment of the present invention.

FIG. 3 is a flow chart for explaining the operation of one embodiment of the present invention.

FIG. 4 is a schematic diagram for explaining the operation of another embodiment of the present invention.

FIG. 5 is a part of a flow for explaining the operation of another embodiment of the present invention.

FIG. 6 is a part of a flow for explaining the operation of another embodiment of the present invention.

FIG. 7 is a flowchart showing the operation of the audio codec.

FIG. 8 is a schematic diagram for explaining the operation of still another embodiment of the present invention.

FIG. 9 is a part of a flow for explaining the operation of still another embodiment of the present invention.

FIG. 10 is a part of a flow for explaining the operation of still another embodiment of the present invention.

FIG. 11 is a part of a flow for explaining the operation of still another embodiment of the present invention.

12A is a diagram showing an AAL type 1 ATM cell format, and FIG. 12B is a diagram showing an AAL type 2 ATM cell format.

FIG. 13 is a diagram illustrating an example of a conversion processing process in the AAL converter 13.

FIG. 14 is a system schematic block diagram showing a conventional technique.

[Explanation of symbols]

11 ATM switch 12 sound sources 13 AAL converter 14 audio codecs 15 ATM-STM converter for AAL1 16 PCM subscriber terminal 17 ATM-STM converter for AAL1 18 ADPCM subscriber terminal 19 ATM-STM converter for AAL2 20 CS-ACELP subscriber terminal

Continuation of front page (56) Reference JP-A-1-152894 (JP, A) JP-A-6-284183 (JP, A) JP-A-4-363698 (JP, A) JP-A-63-136797 (JP , A) JP 2000-31996 (JP, A) JP 10-262051 (JP, A) JP 9-64906 (JP, A) JP 11-331957 (JP, A) JP 11 -289336 (JP, A) Patent 2818616 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12/56

Claims (7)

(57) [Claims] 1. A tone connection system for connecting a tone signal to a subscriber terminal corresponding to an ATM cell type type or a voice coding rule type via an ATM switch. and tone signal generating means for outputting a PCM signal as a predetermined one cell of the ATM type type of speech coding rule of converting the ATM cells tone PCM signal from the tone signal generator according to said speech coding rules Conversion means, type classification conversion means for converting the ATM type classification of the ATM PCM tone PCM signal into another type classification, and in response to a tone signal connection request from the subscriber terminal,
In accordance with the type classification and the voice coding law of the subscriber terminal, the voice coding rule conversion means and the type classification conversion means are selectively controlled by the ATM switch to output the tone signal from the tone signal generation means. A tone connection system comprising: a control unit that converts and supplies a tone signal corresponding to a subscriber terminal. 2. The control means has a database in which specific information is stored in advance in order to specify a corresponding type classification or a corresponding voice coding rule classification of each of the subscriber terminals,
In response to a tone signal connection request from the subscriber terminal,
The correspondence specifying information of the subscriber terminal is read from the database, and the AT controls the selection of the voice coding rule converting means and the type classification converting means according to the specifying information.
The tone connection system according to claim 1, wherein the tone connection system is configured by an M switch. 3. The control means sets control information according to the specific information in a header of the ATM cellized signal, and the selection control is performed by the control information. The tone connection system according to claim 2. 4. The tone connection system according to claim 3, wherein the control information is an identifier for identifying a connection in the header. 5. When the subscriber terminal is PCM compatible, the control means controls the ATM PCM signal without converting the ATM cell tone PCM signal into the voice coding rule conversion means or the type classification conversion means. 5. The tone connection system according to claim 1, wherein the tone connection system is controlled to be supplied to the subscriber terminal via a switch. 6. The subscriber terminal is ADPCM (Adaptive).
In the case of Differential PCM), the control means is configured to convert the ATM cellized tone PCM signal into the ATM.
5. The tone connection system according to claim 1, wherein the switch, the voice coding rule conversion means, and the ATM switch are controlled so as to be supplied to the subscriber terminal in this order. 7. The subscriber terminal is CS-ACELP (Co
njugate Structureand Algebraic Code-Excited Linear
Prediction) support, the control means is the AT
The tone PCM signal converted into M cells is the ATM switch, the voice coding rule conversion means, the ATM switch,
The tone connection system according to any one of claims 1 to 4, wherein the type classification conversion means and the ATM switch are controlled so as to be supplied to the subscriber terminal through this order.