JPH10135977A - Cell transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the cell transmission system in which the criterion for voiced sound/silence is changed. SOLUTION: Information to revise a threshold level K of a setting level of a voiced cell P sent from an opposite party is added to a voiced cell P as a speech quality information Q, by a speech quality addition section 5 in the case of the transmission of its own station and the resulting cell is sent from a cell assembly section 3. On the other hand, a reception section of the opposite party uses a de-cell processing section 11 for extracting the speech quality information Q from the voiced cell P to be received and after a speech quality detection section 13 detects the speech quality information Q, and a criterion generating section 15 revises the threshold level into a threshold level K suitable for the speech quality. Thus, the voiced cell P as a result of new level setting is sent from a transmission section of a telephone set having the reception section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell transmission system and, more particularly, to an ATM (Asynchronous) system for transmitting voice signals.
Transfer Mode) The present invention relates to a cell transmission system that converts cells into cells and transmits the cells.

[0002]

2. Description of the Related Art This type of cell transmission system is disclosed in
No. 83288. FIG. 6 is a configuration diagram of this conventional cell transmission system.

[0003] This conventional cell transmission system includes a transmitting side 1
00, a switching network 101, and a receiving side 102. The transmitting side includes an encoding unit 103, a voice detection unit 104, and a cell assembling unit 105.

[0004] When the voice detection section 104 detects a voiced section having a voice signal, the coding section 103 performs high-rate coding. The cell assembling unit 105 sets the high-rate coded output signal as a voiced cell, sets the low-rate coded output signal as a silent cell, and sets the cell discarding priority of the silent cell to a high value. Receiving side 102
Send to

A feature of this system is that a speech signal in a sound section is encoded at a high rate, but in a silent section, only a background noise is encoded at a low rate.

As a result, it is possible to improve the transmission efficiency as compared with a case where each of the sound section and the silent section is simply made into a cell, and the receiving side is in a state close to the background noise on the transmitting side. Can be reproduced in a silent section, so that a sense of incongruity does not occur.

Further, since the priority of discarding silent cells is set high, silence is preferentially discarded when the network is congested. However, the content of the call is not affected because of the silent section.

Further, the transmission efficiency is further improved by transmitting the background noise information into cells at a certain interval instead of transmitting the entire silent section as background noise cells.

Further, another cell transmission system of this kind is disclosed in Japanese Patent Application Laid-Open Nos. 4-923 and 3-254262.

In the system disclosed in Japanese Patent Laid-Open No. 4-923, when audio data is input, encoding is performed at a different encoding rate for each frame, and encoding of a sound part detected by the audio detecting means is performed. Only data is stored,
When encoding rate information for notifying the destination of the audio data of the encoding rate for each frame is generated, compression is performed, and an ATM cell including the compressed encoding rate information is created.

On the other hand, the system disclosed in Japanese Patent Application Laid-Open No. 3-254262 performs coding and cellization in the case of speech by speech detection, and temporally converts information of a silent section in the case of silence. Monitoring is performed, and after the end of the silent period, the time information of the silent period is multiplexed and transmitted to the cell.

[0012]

However, in these cell transmission systems, since the criterion for determining whether there is sound or no sound is fixedly determined, the sound period and the soundless period are subjectively determined by the caller. However, there is a disadvantage that some callers may be dissatisfied with the call quality (voice level, voice clarity, etc.).

[0013] Since a voiced cell is always cellized at the same rate irrespective of the network congestion state, if a voiced cell continues to arrive in a network congestion state, the cell is discarded and communication is impaired. And recovery from the network congestion state is delayed.

Therefore, an object of the present invention is to change the criterion for determining whether there is sound or no sound, reduce the number of cells transmitted in a congested state, reduce the load on the network, and reduce the load on the congested state. An object of the present invention is to provide a cell transmission system capable of alleviating mitigation and maintaining communication.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a voiced cell generator which compares a level of an input voice with a predetermined threshold to a voice unit and converts voices above the threshold into voiced cells. Means, speech quality information adding means for adding speech quality information to the voiced cell generated by the voiced cell generation means,
And transmitting means for transmitting the voiced cell to which the voice quality information is added by the voice quality information adding means to the partner station, and transmitting the voiced cell to which the voice quality information transmitted from the partner station is added to the receiving unit. Receiving means for receiving, call quality information detecting means for detecting the call quality information from the voiced cells received by the receiving means, and changing the threshold value based on the call quality information detected by the call quality information detecting means And a voice decoding means for decoding a voice from the voiced cell received by the receiving means.

According to another aspect of the present invention, the receiving unit further includes cell loss detecting means for detecting a predetermined number or more of cell loss, and when the cell loss detection is performed by the cell loss detecting means, the threshold value changing means includes: The threshold value is increased.

According to the present invention, when the transmitting unit adds the speech quality information to the voiced cell and transmits it, the receiving unit of the other station that has received the voiced cell and the speech quality information transmits the speech quality information to the received speech quality information. Then, the threshold of the level of the input voice of the station is changed. Then, the voiced cell generated by the new threshold is transmitted.

According to another aspect of the present invention, when the cell loss detecting means detects the cell loss, the cell loss detecting means determines that the network is in a congested state, and sends a higher threshold value to the threshold value changing means. Output. The threshold changing means changes the threshold to the new threshold.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram of an embodiment of a transmission / reception unit of the cell transmission system according to the present invention.

Although this cell transmission system is not shown, the whole system is composed of one transmitting / receiving section, the other transmitting / receiving section, and a switching network connecting these two transmitting / receiving sections (see FIG. 6). Is the same as Therefore, illustration of the overall configuration of the cell transmission system is omitted.

A feature of the present invention lies in the configuration of the transmitting / receiving section.
The transmitting / receiving unit is a transmitting / receiving unit using a push-button dial signal type telephone, and inputs a partner telephone number or the like by an input device such as a push button provided on the telephone or a push button provided on the transmitting / receiving unit. It is.

The transmitting section of the transmitting / receiving section includes a sound determining section 1 for determining whether the input voice is voiced or silent, and an encoding for coding the voice including the determination information in the voiced determining section 1. Unit 2, a cell unit 3 for converting the speech determined to be speech among the speech encoded by the encoding unit 2 into cells, and a push-button dial signal (hereinafter, referred to as a "phone") input by a push button of a telephone or the like. A PB (Push Button) signal), and speech quality information Q corresponding to the PB signal detected by the PB signal detection unit 4 is converted to a voice P cellized by the cellization unit 3. And a call quality information adding unit 5 for adding the call quality information. Further, although not shown, the celling unit 3
And a transmission circuit for transmitting the voiced cell P and the communication quality information Q which are converted into cells.

On the other hand, the receiving section includes a receiving circuit (not shown) for receiving the voiced cell P and the communication quality information Q transmitted from the partner station, and a voiced cell P and the communication quality information Q received by the receiving circuit. And a decoding unit 12 for decoding a voice from the sound cell P decomposed by the deceleration unit 11.
A call quality detecting unit 13 for detecting a call quality from the call quality information Q decomposed by the decell unit 11, a cell loss monitoring unit 14 for detecting a cell loss from the voiced cell P decomposed by the decel unit 11, A determination criterion generator 15 for changing a threshold value K for a sound determination level in accordance with signals output from the quality detector 13 and the cell loss monitoring unit 14, and a transmitter based on the threshold K changed by the criterion generator 15. The sound determination section 1 makes a sound determination.

FIG. 2 is a schematic illustration of an example of the audio frame format. This format is 16kLD-C
An example is shown in which a speech cell is transmitted by the AAL1 (according to ITU-T I.363 recommendation) function in the case of ELP (according to ITU-T G.728 recommendation) speech coding.

In the 16k-LDCELP speech coding method, it is determined whether or not a frame is a voiced frame in one bit (extended bit E) of one frame (320 bits). , A flag indicating whether the frame is a silence frame (“0” for a speech frame and “1” for a silence frame) is added, and the flag is used to identify speech or silence. The bit S is a frame synchronization bit.

The 320-bit audio frame is generated by the encoder 2.

Further, in the present embodiment, the speech quality information Q consisting of 56 bits is added by the speech quality adding section 5 to the front part (or the rear part) of the voice frame. The call quality information Q is information for changing the threshold value K for the sound determination on the partner station side.

For example, when it is difficult to hear the voice of the other party during a call with the other station, the caller operates a push button of a telephone or the like in a direction to improve the call quality, and controls the sound determination criteria of the other station. . On the other hand, for a push button of a telephone or the like, it is prearranged that, for example, pressing "2" increases the call quality, and pressing "8" decreases the call quality.

FIG. 3 is a sound level vs. time characteristic diagram showing the cell transmission control when the sound determination criterion is variable. The judgment criteria A, B, and C in FIG. In the figure, when the threshold K is high (criterion A), the number of transmitted voiced cells P is the smallest, and when the threshold K is intermediate (determination criterion B), the number of voiced cells P increases, When the threshold value K is low (criterion C), it indicates that the sound cell P is continuously transmitted.

In other words, if it is difficult to hear the other party's voice while talking according to the criterion A, the criterion may be lowered to B or C. If it is difficult to hear the other party's voice while talking on the criterion B, the criterion may be lowered to C.

Further, as will be described later, when the network is in a congested state, the threshold K is forcibly used as the criterion A, so that the transmission amount of the voiced cell P is reduced as much as possible. By transmitting only the voiced cells P having an extremely high voice level, it is possible to maintain the communication, reduce the load on the network, and recover from congestion at an early stage.

A cell loss monitoring unit 14 provided in the receiving unit monitors cell loss by checking a sequence number, determines that a cell loss of a specified amount or more has occurred within a predetermined time as congestion, and determines a criterion generation unit. 15 is forcibly controlled to the maximum value of the silence judgment reference, that is, the threshold value A. Sound existence judgment part 1
Performs a sound / non-sound determination using the threshold value A from the determination criterion generation unit 15 as a reference value.

The sequence number is assigned a value from 0 to 7 (modulo 8) by the cell unit 3, the order is monitored by the decell unit 11, and the monitoring result is sent to the cell loss monitoring unit 14.

For example, if a cell with a sequence number of 6 is received after a cell with a sequence number of 3 is received, the cell loss monitoring unit 14 determines that two cells with a sequence number of 4 and 5 are missing. .

Next, the operation of the transmitting / receiving section will be described with reference to a flowchart. FIG. 4 is a flowchart showing the operation of the transmitting unit, and FIG. 5 is a flowchart showing the operation of the receiving unit.

First, the operation of the transmitting section will be described with reference to FIGS. First, it is checked whether or not the voice uttered by the caller is equal to or greater than a threshold K (S1). This is based on a threshold value K defined in advance by the criterion generation unit 15,
The sound determination unit 1 makes the determination.

If the value is equal to or larger than the threshold value K, the voice is coded by the coding unit 2 and further cellized by the celling unit 3 (S2).

Next, it is determined whether or not the call quality is to be set (S3). If the caller finds it difficult to hear the other party's voice during the call, the call quality is set (S
4). This is performed by operating the push button of the telephone or the like in the direction of improving the call quality as described above.

Next, the set call quality information Q is added by the call quality adding unit 5 to the voiced cell P in the cell unit 3. Then, the voiced cell P to which the call quality information Q is added is transmitted from the transmission circuit (S5).

On the other hand, if the speech quality is not set in S3, the process proceeds to S5, where the voice cell P is transmitted from the transmitting circuit (S5).
5).

If the input voice is less than the threshold value K in S1, the operation ends because no voiced cell P is generated. The operations from S1 to S5 are repeated as long as a voice is input.

Next, the operation of the receiving section will be described with reference to FIGS. This operation shows the operation of the receiver of the other party that has received the voiced cell P and the speech quality information Q transmitted earlier.

First, the receiving circuit receives the voiced cell P and the communication quality information Q (S11). Next, the voiced cell P and the speech quality information Q are decomposed by the decelerating unit 11 (S12).
Then, the decomposed sound cell P is decoded by the decoding unit 12 and output as voice (S13).

Next, the disassembled speech quality information Q is input to the speech quality detector 13 to detect speech quality (S14). Then, the threshold K corresponding to the detected call quality is generated by the criterion generator 15 (S15).

That is, if the call quality is "increase the call quality because the voice is difficult to hear", the threshold K is lowered. As a result, a transmitting unit such as a telephone having the receiving unit transmits a sound cell which is easy to hear (that is, has an increased amount of information) to the partner station.

On the other hand, if the content is "decrease the communication quality", the threshold K is increased.

Next, the order of the sequence numbers of the voiced cells P input to the decellularizing unit 11 is monitored by the cell loss monitoring unit 14 by the method described above, and it is determined whether or not a certain number of missing cells has occurred. Check (S16).

When it is determined by the cell loss monitoring unit 14 that a certain number of missing cells has occurred (that is, when it is determined that the network is congested), the criterion generation unit 15
Is a criterion, that is, the threshold value K is forcibly increased to a maximum (for example, FIG.
(S17). As a result, the number of transmitted voiced cells P is limited to those having an extremely high voice level, so that the number of voiced cells P is reduced, and congestion can be alleviated. This ends the operation.

On the other hand, if no cell loss occurs in S16, the criterion set previously is used as it is. This ends the operation.

The operations from S11 to S17 are repeated each time a sound cell P is received.

According to the operation procedure shown in FIG. 5, voice output (S13), speech quality detection (S14), and cell loss monitoring (S16) are performed in time series. This order is for convenience.
Actually, these three operations are performed in parallel.

That is, voice output operates in the order of S12, S13, and end, speech quality detection operates in the order of S12, S14, S15, and end, and cell loss monitoring operates in the order of S12, S16, S17, and end.

[0053]

According to the present invention, a sound cell generating means for comparing a level of an input sound with a predetermined threshold value to a transmitting section and converting the sound higher than the threshold value into a sound cell, and the sound cell generating means. A call quality information adding unit that adds call quality information to the sound cell generated in the above, and a transmission unit that transmits the sound cell to which the call quality information is added by the call quality information adding unit to a partner station, A receiving unit for receiving a voiced cell to which a call quality information transmitted from a partner station is added to a receiving unit; and a voice quality information detecting unit detecting the voice quality information from the voiced cell received by the receiving unit. A threshold changing unit that changes the threshold based on the communication quality information detected by the communication quality information detecting unit; and a voice decoding unit that decodes voice from a voiced cell received by the receiving unit. Or no sound Can be changed is one of criteria in.

According to another aspect of the present invention, the receiving unit further has cell loss detecting means for detecting a predetermined number or more of cell loss, and when the cell loss detection means detects the cell loss, the threshold value change is performed. Since the means is configured to increase the threshold, it is possible to reduce the load on the network by reducing the number of cell transmissions in a network congestion state, thereby alleviating the congestion state and maintaining communication.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a transmission / reception unit of a cell transmission system according to the present invention.

FIG. 2 is a schematic diagram illustrating an example of an audio frame format of the system.

FIG. 3 is a sound level versus time characteristic diagram showing cell transmission control when the sound determination criterion is variable in the system.

FIG. 4 is a flowchart showing an operation of a transmission unit of the system.

FIG. 5 is a flowchart showing an operation of a receiving unit of the system.

FIG. 6 is a configuration diagram of a conventional cell transmission system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Voice existence judgment part 2 Encoding part 3 Celling part 5 Communication quality information addition part 11 Decell part 12 Decoding part 13 Communication quality detection part 14 Cell loss monitoring part 15 Judgment standard generation part

Claims (4)

[Claims] 1. A voiced cell generation means for comparing a level of an input voice to a transmission unit with a predetermined threshold value and converting voices having the threshold value or more into voiced cells, and a voiced cell generated by the voiced cell generation means. A call quality information adding unit for adding call quality information to the cell; and a transmitting unit for transmitting a voiced cell to which the call quality information has been added by the call quality information adding unit to a partner station. Receiving means for receiving the transmitted voiced cell to which the call quality information is added; voice quality information detecting means for detecting the voice quality information from the voiced cell received by the receiving means; Threshold value changing means for changing the threshold value based on the speech quality information detected by the detecting means; and voice decoding means for decoding a voice from a voiced cell received by the receiving means. Cell transmission system. 2. The transmission unit and the reception unit are a transmission unit and a reception unit of a push-button dial signal type telephone, and the call quality information adding unit inputs the call quality information by the push button. The cell transmission system according to claim 1. 3. The reception unit further includes cell loss detection means for detecting a predetermined number or more of cell loss, and when the cell loss detection means detects the cell loss, the threshold value change means sets the threshold value to 3. A cell transmission system according to claim 1, wherein 4. The cell transmission system according to claim 3, wherein said cell loss detecting means monitors the order of said cells and, when the order is discontinuous, determines that a cell is missing.