JP6574113B2 - Voice quality degradation prevention system and voice quality degradation prevention method - Google Patents

Description

  The present invention relates to a voice quality degradation prevention system and a voice quality degradation prevention method capable of preventing voice quality degradation in a videophone using an IP network in which voice quality is given priority over video such as emergency calls.

  In recent years, smartphones have become widespread, and everyone can easily distribute and collect various information. When an emergency occurs, a general whistleblower can make an emergency call using the video phone function via the IP network. It is envisaged to do.

  In addition, the following patent document 1 is cited as a document describing a technique for making an emergency call using a smartphone, and patent documents 2 and 3 are cited as a document describing a technique related to jitter, which is a fluctuation in communication delay. It is done.

  Patent Document 1 states that “a communication device (for example, a smartphone) 1 is connected to a communication unit that performs a call using the first communication method or the second communication method; A control unit that causes the communication unit to make a call by a communication method, for example, when the smartphone 1 cannot make a call by the PHS method, the communication unit automatically makes a call by the 3G method. is there.

  Patent Document 2 discloses that a deviation width between a jitter time series generated by an ARCH type model and a jitter time series generated by an exponential smoothing method is calculated, and the jitter generated by the ARCH type model is calculated using the deviation width. There is a description that “a time series is corrected, and a predicted time series of future jitter is generated using the corrected jitter time series and an ARCH type model”.

  Patent Document 3 has a description that “call quality is predicted with high accuracy by performing quality measurement using the same communication method as that of an actual call prior to the call”.

JP 2013-2391979 A Japanese Patent Application Laid-Open No. 2014-135585 JP 2014-192710 A

  The technology described in each of the above-mentioned patent documents only has an effect of reducing the jitter of a call using a smartphone.

  Therefore, the present invention provides a voice quality degradation prevention system and a voice quality degradation prevention method capable of preventing voice quality degradation of an IP videophone using a smartphone in an environment where a high load is applied on the network. With the goal.

ただし、ジッタ累積値をＪ _{ａｍｏｕｎｔ} 、ジッタ平均値Ｊ _ｍｅａｎ を連続して超えるパケットのシーケンス番号をＳ _１ ，Ｓ _２ ，Ｓ _３ ，・・・Ｓ _ｎ 、音声品質Ｒ値をｒ、ａｂｄを定数とする。 According to the voice quality degradation prevention system and voice quality degradation prevention method of the present invention, the real-time jitter cumulative value when the emergency call information management apparatus on the receiving side is using the videophone is set to a predetermined allowable jitter cumulative value based on Equation 7 below. When it exceeds, a voice quality degradation prediction notification is transmitted to the smartphone, and the smartphone receiving the voice quality degradation prediction notification reduces the bit rate when packetizing video information to reduce the amount of video information.

However, the jitter accumulation value _{J AMOUNT,} the sequence number of packets exceeding continuously jitter average _{J mean S 1, S 2,} S 3, ··· S n, the voice quality R value r, and the constant abd To do.

  The voice quality degradation prevention system and voice quality degradation prevention method according to the present invention can prevent voice quality degradation in a videophone using an IP network in which voice quality is given priority over video.

It is a figure which shows the structure of the audio | voice quality degradation prevention system by the Example of this invention. It is a figure for demonstrating operation | movement of the audio | voice quality degradation prevention system by a present Example.

  Examples according to the present invention will be described below.

[Constitution]
As shown in FIG. 1, a voice quality deterioration prevention system to which a voice quality deterioration prevention method according to the present embodiment is applied includes a smartphone 100 having an emergency call unit 11 and a video information control unit 12, a detection unit 23, a call control unit 22, and the like. It is comprised from the emergency call information management apparatus 200 which has the report reception part 24. FIG.

  The smartphone 100 is a portable terminal having a general call function, a photo shooting function, and other functions. In addition to a normal voice call function and a video shooting function via an IP network, the smartphone 100 performs an emergency call that is a feature of this embodiment. A voice quality degradation prediction notification is received from the emergency call unit 11 for performing and a detection unit 23 of the emergency call information management device 200 described later, and the bit rate when packetizing the video information is reduced to reduce the amount of video information And a video information control unit 12 having a function to be configured, and these functions are configured by hardware or software.

  The notification receiving unit 24 of the emergency call information management device 200 receives an emergency call received from the emergency call unit 11 of the smartphone 100, starts a videophone call, receives and reproduces a voice / video packet, and sends the emergency call unit 11 Has a function of transmitting only voice packets.

  The detection unit 23 measures a real-time jitter (communication delay fluctuation) accumulated value during use of the videophone received by the notification receiving unit 21 via the IP network, and allows an allowable jitter accumulation derived by a prediction formula described later. It has a function of transmitting an audio quality deterioration prediction notification to the video information control unit 12 when the value is exceeded.

  The call control unit 22 has a function of relaying packets transmitted and received between the emergency call unit 11 and the call reception unit 21 and adjusting the reproduction timing of audio / video packets.

  A method for deriving an allowable jitter cumulative value using a prediction formula of a real-time jitter (communication delay fluctuation) cumulative value during videophone use by the detection unit 23 is as follows.

1. Derivation of acceptable packet loss rate using speech quality value The relationship between speech quality and packet loss is expressed in numerical form, and an acceptable packet loss rate is derived. In order to numerically evaluate the voice quality, the voice quality value R is used (* the voice quality R value is a voice quality index determined by the VOIP promotion council of the Japan Telecom Service Association). Using IP videophone, load the network environment and measure packet loss rate and voice quality value. An exponential regression equation is obtained from the measured value. Taking the voice quality R value on the y-axis and the packet loss rate on the x-axis, the exponential approximation shown in the following equation 1 is obtained.

  The voice quality R value to be maintained here is arbitrarily set, and an acceptable packet loss rate is derived. When the voice quality R value to be maintained is r (r: constant) and the allowable packet loss rate is P, these are substituted into Equation 1 and transformed into an equation with natural logarithm on both sides, then Equation 2 is obtained, An acceptable packet loss rate P is obtained.

2. Derivation of relational expression between jitter and packet loss Since jitter suddenly increases as a precursor to packet loss occurrence, a relational expression between the cumulative jitter value and the number of packet losses is derived. An IP videophone is used in an environment where a load is applied to the network, and the jitter and the number of packet losses are measured when a voice packet sent from a smartphone reaches the call control unit. At this time, the IP videophone call is performed in a state where the network load is normal in advance, the jitter of each voice packet received by the call control unit is measured, and the jitter average value J _mean is derived. Next, the jitter accumulated value _Jmount is measured in a state where a load is applied to the network.

The jitter accumulation value _{J AMOUNT} is calculated by the jitter values of packets that exceed continuously jitter average _{J mean J 1, J 2,} J 3 Equation 3 when a · · · _{J n.}

From the measured value, the number of packet losses is taken on the y-axis and the jitter accumulated value is taken on the x-axis to obtain a single regression equation y = cx + d (c, d: constant). Thus the packet loss count _{P AMOUNT} is expressed as _{P amount = cJ amount} + d using the jitter accumulation value _{J AMOUNT.}

3. By derived the deriving the packet loss rate of the allowable jitter accumulation value, Sadamari a limit value of the jitter accumulation value _AMOUNT, following a calculation method when the limit value and the allowable jitter accumulation value.

A packet loss rate P and Equation 4, the sequence number of packets exceeding continuously jitter average _{J mean S 1, S 2,} S 3, when a · · · _{S n,} the total received voice packets _S n _-S 1 +1 in number of packets, substituting _{P amount = cJ amount} + d obtained above to the number of packet losses.

  Further, by transforming Equation 5 using the allowable packet loss rate P (allowable packet loss rate) obtained above, the following Equation 6 for obtaining the allowable jitter accumulated value can be obtained. Thus, the allowable jitter accumulated value can be derived as Equation 7.

[Operation]
The voice quality deterioration prevention system configured as described above executes each step of the processing flow shown in FIG. 2 when the application of the emergency call unit 11 of the smartphone 100 is activated and the emergency call information management apparatus 200 is receiving a call. Accordingly, it is possible to prevent the deterioration of the voice quality in the video phone using the IP network in which the voice quality is given priority over the video such as the emergency call.

Step 101: A step in which the smart phone 100 starts using the emergency call unit 11 with a videophone function by an operation of the caller.
Step 102: The smart phone 100 transmits the emergency communication using the video phone function by the emergency call unit 11 started by the step 101 and the emergency communication by the photographed video to the report reception unit 24 of the emergency call information management device 200.

Steps 201 to 202: A step in which the report receiving unit 24 of the emergency call information management apparatus 200 receives and receives an emergency call from the emergency call unit 11.
Step 203: A step in which the detection unit 23 monitors a voice packet included in an emergency call from the smartphone 100 and starts measuring a jitter cumulative value for measuring a jitter cumulative value.

  Step 204: Comparing the jitter accumulated value of the voice packet measured in step 203 with the allowable jitter accumulated value set in advance based on the above-mentioned equation 7, it is determined whether or not the jitter accumulated value exceeds the allowable jitter accumulated value. Determining.

  Step 205: A step of determining that the voice quality degradation occurs when the step 204 judges that the cumulative jitter value exceeds the allowable jitter cumulative value, and transmitting a speech quality degradation prediction notification to the smartphone 100.

Step 103: A step of reducing the amount of video information by reducing the bit rate when the video information control unit 12 that has received the audio quality degradation prediction notification in step 205 packetizes the video information.
The processing from step 203 to step 205 is repeatedly executed at the time of emergency notification.

  As described above, the voice quality degradation prevention system according to the present embodiment measures the real-time jitter (communication delay fluctuation) accumulated value while using the videophone call received by the emergency call information management apparatus 200, and exceeds the allowable jitter accumulated value. At the same time, a detection unit 23 for transmitting an audio quality degradation prediction notification is provided, and the smartphone 100 receives the audio quality degradation prediction notification from the detection unit 23 to reduce the bit rate when packetizing video information. A video information control unit 12 having a function of reducing the video information amount is provided. And the detection part 23 of the emergency call information management apparatus 200 measures the jitter cumulative value of the voice packet included in the emergency call from the smartphone 100, and the measured jitter cumulative value exceeds the predetermined allowable jitter cumulative value. When the determination is made, an audio quality degradation prediction notification is transmitted to the smartphone 100, and the video information control unit 12 that has received the audio quality degradation prediction notification reduces the bit rate when packetizing the video information to reduce the amount of video information. Let Thereby, the voice quality deterioration prevention system according to the present embodiment can prevent the voice quality deterioration of the IP videophone using the smartphone in an environment in which a high load is applied on the network.

11 Emergency call section, 12 Video information control section, 22 Call control section, 23 Detection section,
24 Report reception unit, smartphone 100, 200 Emergency call information management device

Claims (2)

Reduces the bit rate when packetizing video information when receiving voice quality degradation prediction notifications, and an emergency call unit for making voice calls and video shooting functions via the IP network and emergency calls via videophone A smartphone having a video information control unit that reduces the video information amount,
Accepts an emergency call received from the emergency call unit of the smartphone, starts a videophone call, receives and reproduces an audio / video packet, and a real-time jitter during videophone use received by the call reception unit An emergency call information management device having a detection unit that measures a cumulative value and transmits a voice quality degradation prediction notification to a video information control unit when the jitter cumulative value exceeds a predetermined allowable jitter cumulative value;
A voice quality degradation prevention system comprising:
The detection unit is
Jitter accumulation value _{J amount, S} 1 the sequence number of packets exceeding continuously jitter average value _{J mean, S 2, S 3} , ··· S n, voice quality R value r, when a constant abd The allowable jitter cumulative value is set as the limit value of the jitter cumulative value _Jmount shown in the following Equation 7 ,
First, when a jitter accumulated value of a voice packet included in an emergency call is measured from a smartphone and it is determined that the measured jitter accumulated value exceeds the allowable jitter accumulated value , a first voice quality degradation prediction notification is transmitted to the smartphone. Process,
The video information control unit that has received the voice quality degradation prediction notification in the first step,
A second step of reducing the video information amount by lowering the bit rate when packetizing the video information;
Perform voice quality degradation prevention system.

Reduces the bit rate when packetizing video information when receiving voice quality degradation prediction notifications, and an emergency call unit for making voice calls and video shooting functions via the IP network and emergency calls via videophone A smartphone having a video information control unit that reduces the video information amount,
Accept an emergency call arriving from the emergency reporting unit of the smart phone, to start a video call, the call receiving part for receiving and reproducing audio and video packets, the jitter accumulation value J _AMOUNT, continuously jitter average value J _mean sequence number of the packet that exceeds Te of _{S 1, S 2, S 3} , ··· S n, voice quality R value r, when a constant abd, the allowable jitter accumulation value, jitter accumulation shown in the following equation 7 is set as the limit value of the value J _AMOUNT, measures the real-time jitter accumulation values during a videophone call using said call receiving unit receives, when the measured jitter accumulation value exceeds a predetermined the allowable jitter accumulation value An emergency call information management device having a detection unit that transmits a voice quality degradation prediction notification to the video information control unit,
An audio quality degradation prevention method for a computer system comprising:
The detection unit, when to measure the jitter accumulation value of the audio packets included in the urgent message from the smartphone determines that jitter accumulation value measured exceeds a predetermined the allowable jitter accumulation value, sound quality smartphone The first step of transmitting the deterioration prediction notification is executed,
In the video information control unit that has received the voice quality degradation prediction notification in the first step,
Executing a second step of reducing the video information amount by lowering the bit rate when packetizing the video information;
Voice quality degradation prevention method.

Images