JP2842525B2 - Audio compression cellization system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio compression cellization system for accommodating an audio signal compressed silently in an ATM communication network.

[0002]

2. Description of the Related Art Conventionally, as a technique related to this type of voice cell system, for example, a voice encoder disclosed in Japanese Patent Application Laid-Open No. 5-244104 is cited.

In this speech encoder, in order to apply the speech encoder to an ATM communication network, the range of silence compression is limited, and the redundancy of the speech signal is suppressed to maintain the naturalness of the speech signal.

FIG. 5 is a block diagram showing a basic configuration of the speech encoder. The speech encoder here is a signal compressor 301 that compresses and encodes an input signal from a telephone and outputs a coded signal, and a cell that receives this coded signal and assembles cells to generate a cell signal. Output cell assembler 302
And a transmission buffer 303 for temporarily storing a plurality of cells assembled in the cell signal and sequentially transmitting the cells as an output signal to a line, and a detection signal indicating a result of detecting a cell storage amount in the transmission buffer 303 based on the output signal. And a signal compressor 301 that compares the cell storage amount with a predetermined value based on the detection signal and increases the degree of signal compression when the cell storage amount is larger than the predetermined value. And a comparator 305 for outputting a control signal.

[0005] That is, regarding the operation of the speech encoder, first, the signal compressor 301 compresses and encodes an input signal from the telephone, and outputs an encoded signal. Next, the cell assembler 302 receives the encoded signal from the signal compressor 301, assembles the cell, and outputs a cellized signal. Subsequently, the transmission buffer 303 receives the cell signal, temporarily stores a plurality of assembled cells, and sequentially transmits the cells as output signals to the line.

On the other hand, the detector 304 receives the output signal, detects the cell storage amount of the transmission buffer 303 and outputs a detection signal, and the comparator 305 receives the detection signal and determines the cell storage amount and a predetermined threshold. As a result, when the cell storage amount is larger than a predetermined threshold value, a control signal for controlling the signal compressor 301 to increase the degree of signal compression is output.

Therefore, in this voice encoder, when the cell storage amount of the transmission buffer 303 is smaller than a predetermined threshold, the degree of signal compression is suppressed, and the quality of a transmission signal is improved.

[0008]

In the case of the above-mentioned speech encoder, since the control of the degree of compression of the speech signal is performed based on the absolute value of the cell storage amount in the transmission buffer of the own circuit, the output signal is low. There is a problem that it is impossible to perform control corresponding to the congestion state of the ATM line other than the ATM line in which the own circuit is accommodated, in the voice path passing unit in the ATM communication network to be transmitted.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and its technical problem is to avoid congestion in the entire ATM communication network and to reduce the sound quality by compressing the voice signal unnecessarily. An object of the present invention is to provide a voice cell system that does not come.

[0010]

According to the present invention, in a voice compression cellization system for compressing an input voice signal and transmitting a cellular signal obtained by cellifying the voice signal to an ATM communication network, a predetermined silence detection threshold value is defined. Silence detecting means for detecting silence of the voice signal based on the comparison, network monitoring means for monitoring the congestion status of the voice path passing unit in the ATM communication network, and threshold control means for controlling the silence detection threshold according to the congestion status When,
A cell compression means is provided which has a cell conversion means for obtaining a cell signal by cellizing only a sound portion of a sound signal in which silence is detected.

According to the present invention, in the above-mentioned voice compression cellularization system, the silence detecting means is a silence detecting circuit for detecting silence in a voice signal in accordance with a silence detection threshold, and the network monitoring means is a congestion state in an ATM communication network. An audio compression cellization system is obtained, which is a network monitoring circuit for monitoring information and voice connection path information, and the threshold control means is a control circuit for controlling a silence detection threshold based on the congestion status information and the voice connection path information.

Further, according to the present invention, in any of the above-mentioned audio compression cellization systems, the cellization means encodes an audio signal detected as silence and outputs an encoded signal; And a silent compression cell assembling circuit for converting only a sound portion of the converted signal into cells and outputting a cell signal.

[0013] In addition, according to the present invention, in any of the above voice compression cellularization systems, there is provided an ATM interface circuit for transmitting a cellularized signal to an ATM communication network, and the network monitoring circuit comprises an ATM interface circuit. A voice compression cellularization system for monitoring the inside of the ATM communication network is obtained.

Further, according to the present invention, in any of the above-mentioned voice compression cellization systems, the voice compression cellization system includes an external connection communication means connected to a control circuit for externally commanding a silence detection threshold value. The system is obtained.

[0015]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a basic configuration of an audio compression cellularization system according to one embodiment of the present invention.

The speech compression cellization system comprises a silence detection means for detecting silence of an audio signal input from the audio signal line 16 based on a comparison with a predetermined silence detection threshold,
A network monitoring means for monitoring a congestion state of a voice path passing unit in the M communication network 18, a threshold control means for controlling a silence detection threshold according to the congestion state, and And a celling means for obtaining a cellized signal.

The silence detecting means includes a silence detecting circuit 1 for detecting silence in an audio signal in accordance with a silence detection threshold.
2, the network monitoring means is a network monitoring circuit 11 for monitoring congestion status information and voice connection path information in the ATM communication network 18, and the threshold control means sets a silence detection threshold based on the congestion status information and voice connection path information. It is a control circuit 10 for controlling.

A cell encoding means encodes an audio signal detected as silence and outputs an encoded signal.
3 and a silent compression cell assembling circuit 14 for converting only the sound portion of the encoded signal into cells and outputting a cell signal.

Further, in this voice compression cell forming system,
ATM for sending cell signal to ATM communication network 18
The network monitoring circuit 11 has an interface circuit 15 via the ATM interface circuit 15.
It monitors the inside of the M communication network 18.

FIG. 2 exemplifies a basic configuration of an ATM communication network system including such a voice compression cell system. Here, the audio terminal 20 is accommodated in the ATM communication network 18 via the audio signal line 16, and the audio terminal 21 is accommodated in the ATM communication network 18 via the audio signal line 17. Further, four ATM relay nodes 22 to 25 are arranged inside the ATM communication network 18, and each of the ATM relay nodes 22 to 25 is connected to four ATM relay lines 26 to 29.
Are connected respectively.

Therefore, it is assumed that a voice path is set between the voice terminal 20 and the voice terminal 21 via the nodes 22, 23, and 24, and each component circuit of the voice compression cellization system shown in FIG. Is assumed to be implemented in the node 22, and as shown in FIG. 3, the congestion status of the ATM trunk lines 26 and 27 is indicated by the relationship of the line usage rate as a quantification parameter with respect to the time (t) axis. I do.

In such a case, in the audio compression cellularization system, the audio path is
Node 22, node 23, node 2 inside M communication network 18
4 and transmits the voice connection path information to the control circuit 10 and, at the same time, notifies the congestion status information of the ATM trunk lines 26 and 27. Control circuit 10
In this case, the determination is made based on the line usage rate of the relay line having the highest line usage rate among all the relay lines of the voice path passing unit.

In the example shown in FIG. 3, the control circuit 10
The line congestion state is managed in three states according to the line utilization rate, and the line utilization rate is controlled from 80% to 100% in states A and 60.
% To 80% is the state B, and 0% to 60% is the state C. Therefore, among all the relay lines of the voice path passing unit, the state of congestion of the relay line having the highest line utilization rate is the state A.
If so, the silence detection threshold is A ', if in state B, B',
In state C, C '(however, A'> B '>C' in this case)
Holds). Therefore, in the control circuit 10, FIG.
At the respective times a, b, c, d, and e, the silence detection threshold is set to C ′ during time a, B ′ during time b,
A 'during time c, B' during time d, and C 'during time e.

That is, in the voice compression cellularization system shown in FIG. 1, the control circuit 10 controls a voice detection threshold value at the time of voiceless detection according to the congestion state of the voice path passing portion in the ATM communication network 18, and then controls the voiceless compression. The cell assembling circuit 14 converts the cellized signal obtained by cellifying only the sound portion of the audio signal detected as silence into A
Since the data is transmitted to the TM communication network 18, it is possible to avoid congestion in the entire ATM communication network and to prevent sound quality deterioration due to useless voice compression.

More specifically, the control circuit 10 sets a high silence detection threshold when network congestion occurs or is expected to occur in the voice path passing section of the ATM communication network 18, but the network resources are limited. If there is enough network congestion is not expected, a low silence detection threshold is set.
When congestion occurs or is expected to occur in the voice path passage section in the communication network 18, the silence detection threshold is set to a high value and the cell signal is transmitted to the ATM communication network 18 to reduce the number of voice cells. Therefore, congestion avoidance of the entire ATM communication network is measured.

On the other hand, if there are sufficient network resources in the voice path passing section in the ATM communication network and congestion is not expected, the silence detection threshold is set to a low value and the cell signal is set to A.
The transmission to the TM communication network 18 prevents the sound quality from deteriorating due to useless speech compression.

FIG. 4 is a block diagram showing a basic configuration of a voice compression cellularization system according to another embodiment of the present invention.

In this voice compression cell conversion system, a console interface as an external connection communication means connected to the control circuit 10 for newly commanding a silence detection threshold from the outside in comparison with the system of the first embodiment. A circuit 30 is provided.

This console interface circuit 30
Is connected to the console terminal, so that the silence detection threshold can be changed from the console terminal, so that the user using the ATM communication network 18 can programmably determine the silence detection threshold. For example, a control program may be provided with a timekeeping function, and a silence detection threshold may be fixedly set low in a specific time zone to emphasize sound quality, or a silence detection threshold may be fixedly set high in a specific time zone. Thus, a user-specific operation that places importance on avoiding congestion in the ATM communication network 18 becomes possible. In addition, services such as giving priority to the voice terminals 20 and 21 accommodated in the ATM communication network 18 and keeping only voice signals from specific voice terminals at a fixed low silence detection threshold to maintain voice quality. Becomes possible.

[0031]

As described above, according to the voice compression cellularization system of the present invention, the threshold control means is controlled in accordance with the congestion status of the voice path passing unit in the ATM communication network obtained by monitoring by the network monitoring means. To control the silence detection threshold at the time of silence detection, and to transmit to the ATM communication network a cell signal in which only the voiced portion of the audio signal detected by the cell forming means is converted to a cell. And avoiding useless compression of the audio signal to lower the sound quality. That is, when congestion occurs or is expected to occur in the voice path passing unit in the ATM communication network, the silence detection threshold is set to a high value to reduce the number of voice cells of the cell signal transmitted to the ATM communication network. Thus, congestion avoidance of the entire ATM communication network is measured, and if there is sufficient network resources in the voice path passing section in the ATM communication network and congestion is not expected, the silence detection threshold is set to a low value and By transmitting the digitized signal to the ATM communication network, it is possible to prevent sound quality deterioration due to useless voice compression.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of an audio compression cellularization system according to an embodiment of the present invention.

FIG. 2 shows an AT including the voice compression cellularization system shown in FIG. 1;
FIG. 1 is a block diagram illustrating a basic configuration of an M communication network system.

FIG. 3 shows the congestion status of a local ATM trunk line in the ATM communication network of the ATM communication network system shown in FIG. 2 in relation to a line utilization rate as a quantification parameter with respect to a time axis.

FIG. 4 is a block diagram showing a basic configuration of an audio compression cellularization system according to another embodiment of the present invention.

FIG. 5 is a block diagram showing a basic configuration of a conventional speech encoder.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 control circuit 11 network monitoring circuit 12 silence detection circuit 13 speech encoding circuit 14 silence compression cell assembling circuit 15 ATM interface circuit 16-17 speech signal line 18 ATM communication network 20-21 speech terminal 22-25 ATM relay node 26-29 ATM trunk line 30 Console interface circuit 301 Signal compressor 302 Cell assembler 303 Transmission buffer 304 Detector 305 Comparator

Claims (5)

(57) [Claims] 1. An audio compression cellization system for compressing an input audio signal and transmitting a cell signal obtained by cellifying the input audio signal to an ATM communication network, wherein a silence of the audio signal is detected based on a comparison with a predetermined silence detection threshold value. Silence detecting means for detecting, network monitoring means for monitoring the congestion status of the voice path passing unit in the ATM communication network, threshold control means for controlling the silence detection threshold according to the congestion status, Celling means for obtaining only the sounded part of the audio signal obtained as a cell to obtain the cellized signal. 2. The speech compression cellization system according to claim 1, wherein said silence detection means is a silence detection circuit for detecting silence in said speech signal in accordance with said silence detection threshold, and said network monitoring means is said ATM communication network. A network monitoring circuit that monitors congestion status information and voice connection path information, wherein the threshold control unit is a control circuit that controls the silence detection threshold based on the congestion status information and the voice connection path information. Speech compression cellularization system. 3. The audio compression cellization system according to claim 1, wherein said cellization means encodes said audio signal in which said silence is detected, and outputs an encoded signal; And a silence compression cell assembling circuit for converting only the sound portion of the converted signal into cells and outputting the cellized signal. 4. The voice compression cellularization system according to claim 2, further comprising an ATM interface circuit for transmitting said cellularized signal to said ATM communication network, wherein said network monitoring circuit comprises said ATM interface circuit. A voice compression cellization system for monitoring the inside of the ATM communication network via the ATM. 5. The voice compression cellularization system according to claim 2, further comprising an external connection communication means connected to said control circuit for externally commanding said silence detection threshold. An audio compression cellization system characterized by the following.