KR20030019839A - Detecting Device for Quality of Conversation in Mobile Communication System and Method Therefor - Google Patents

Abstract

PURPOSE: A device and a method for measuring tone quality in a mobile communication system are provided to measure tone quality in real time, even in the case of a busy state or call disconnection due to software change of a vocoder in a control station. CONSTITUTION: A VAD(Voice Activity Detection) part(100) detects the existence of caller voice, to decide and transmit a rate of encoding the detected voice. An encoder(110) encodes the voice from the VAD part(100). A test vector generator(120) generates pre-stored voice packets and data packets. The first switching part(130) switches voice rates of 1, 1/2 and 1/4 outputted from the VAD part(100) and a data packet rate of 1/8 outputted from the test vector generator(120), for outputting to a base station in a wireless area. A packet detection switching part(140) switches test packets in voice rates of 1, 1/2 and 1/4 when the caller keeps speaking and in voice rates of 1', 1/2', 1/4' and 1/8' when the caller does not speak, from signals delivered from the base station. A decoder(150) receives and decodes the voice rates of 1, 1/2 and 1/4 outputted from the packet detection switching part(140). A PCM(Pulse Code Modulation) detection switching part(160) detects and switches PCM from the voice rates outputted from the decoder(150) for outputting to an exchange. A test vector detector(170) receives the test packets of 1', 1/2', 1/4' and 1/8' outputted from the packet detection switching part(140) and the voice packets of 1', 1/2', 1/4' and 1/8' outputted from the decoder(150) to detect test vector. A synchronizer(180) corrects an error of a start position due to transmission delay between the test vector outputted from the test vector generator(120) and the test vector detected in the test vector detector(170). And a measurer(190) measures quality from data outputted from the synchronizer(180).

Description

Detecting Device for Quality of Conversation in Mobile Communication System and Method Therefor}

The present invention relates to a call quality measuring apparatus of a mobile communication system, and more particularly, to a call quality measuring apparatus and a method for measuring a call quality in real time when a call is in progress as well as when a call is released. It is about.

As the digital mobile communication market has grown rapidly, competition among mobile phone service providers is intensifying. This is accelerating as the number of mobile phone subscribers increases, and along with the demand for call quality and services, the demand for subscribers is diversified. In particular, call quality is an important criterion for determining whether to continue to receive services from each service provider.

1 is a block diagram of a general mobile communication system.

As shown in FIG. 1, the exchanger 10 transmits a call processing request of the mobile terminal 40 to another communication network such as a public switched telephone network through a public network or a dedicated network, so that a mobile communication service can be made, and the exchange ( 10) and a base station controller 20 which transmits / receives a message, and a call transmission request of the control station 20 to the mobile terminal 40, and the call processing of the mobile terminal 40. And a mobile terminal 40 which is operated while stopping at a point that is not moved or specified and receives a mobile communication service in a coverage area of the base station 30.

In the general mobile communication system configured as described above, if the user wants to use the mobile communication service while having the subscriber's own mobile terminal 40 within the coverage area of the base station 30, the control station 20 controls the subscriber to the base station 30. The mobile terminal 40 information of the transfer to the switch 10. Thus, in the mobile communication system, the mobile communication system operates to perform a voice information service or to connect with another communication network according to the request of the mobile terminal 40. The operator performs control and maintenance functions of the control station 20 and the base station 30.

On the other hand, the exchange 10 has a built-in call quality measuring device (not shown) that can measure the call quality.

In this case, the apparatus for measuring call quality measures the degree of degradation for each section by transmitting a pre-stored test vector and comparing the returned vector by loopbacking at a desired stage. For example, the call quality measuring apparatus transmits predetermined pulse code modulation (PCM) data to loopback 1 of the control station 20.

At this time, the transmitted PCM data is retransmitted to the call quality measuring device again by the inner loop, and the degradation degree between the call quality measuring device and the loopback section 1 is measured by comparing and evaluating with the original PCM data which transmitted the returned PCM data. can do. This measurement can be performed in the same manner for the loopback terminal 2 of the base station 30.

In particular, the test vector may be PCM data, packet data, tones, and the like. The comparative evaluation method between the original vector and the retransmitted vector is a BER (Bit Error Rate) for measuring an error rate in bits according to the type of the test vector. For example, methods such as a frame error rate (FER) for measuring an error rate in units of frames and a speech quality measure (SQM) for reducing and calculating a subjective sound quality evaluation value to an objective sound quality evaluation may be used.

However, these existing methods can only be tested on call release. That is, it is only possible to proceed in an OFF-LINE form because it is limited to selectively testing a desired call line for channels without a call. This is only suitable for the purpose of maintaining the channel state.

In addition, since the deterioration information for the wireless section cannot be obtained by limiting the wired section to the entire section on the call line, it is not a quality measuring method for the entire call line.

In addition, in terms of cost, the call quality measuring device has a problem in that an additional cost is required as the capacity is increased by adding a H / W type (board to shelf) for each switch unit in the exchange.

Accordingly, the present invention has been made to solve the above-described problems according to the prior art, and an object of the present invention is not only to release a call due to S / W change of a vocoder in a control station, but also to make a call quality even when a call is in progress. The present invention provides an apparatus and method for measuring call quality in a mobile communication system to measure in real time.

A feature of the apparatus for measuring call quality in a mobile communication system according to the present invention for achieving the above object is to detect the presence or absence of a caller's voice and to encode and transmit the detected voice at a rate. VAD (Voice Activity Detection) unit for determining a, an Encoding unit for encoding the voice output from the VAD, a pre-stored voice packet (packet), a test vector generation unit for generating a data packet And a first switch for switching the voice rates 1, 1/2, and 1/4 outputted from the VAD and the data packet rates 1/8 outputted from the test vector generator to be transmitted to a base station of a radio section. And voice rate 1, 1/2 when the caller continues to speak in the signal transmitted from the base station. A packet detection switching unit for switching test packets at rates 1 ', 1/2', 1/4 ', and 1/8' when not talking to 1/4, and voice output from the packet detection switching unit A decode unit for receiving and decoding rates 1, 1/2, and 1/4, a PCM detection switching unit for detecting and switching a PCM at a voice rate output from the decode unit, and transmitting the same to a switch; and the packet detection switching unit Test packets 1 ', 1/2', 1/4 ', 1/8' outputted from the voice packet 1 ', 1/2', 1/4 ', 1/8' outputted from the decoder A test vector detector for detecting a test vector, a synchronizer for correcting an error in a start position due to a transmission delay between a test vector output from the test vector generator and a test vector detected by the test vector detector; Perform a desired quality measurement on the data output from the synchronizer It consists of a measuring unit.

In addition, a feature of the method for measuring call quality in a mobile communication system according to the present invention for achieving the above object is the step of determining whether the rate (Rate) 1/8 in the presence / absence of the voice, and If it is determined that the rate is not 1/8, the data is transmitted at the rate of 1, 1/2, 1/4, and if the rate is 1/8, the test vector is regarded as an interval without speech. And transmitting the data to the base station and the mobile station when the measurement is completed.

1 is a block diagram of a general mobile communication system;

2A is a block diagram of a first embodiment showing an apparatus for measuring call quality in a mobile communication system according to the present invention;

2B is a block diagram of a second embodiment showing an apparatus for measuring call quality in a mobile communication system according to the present invention;

3a is a diagram showing a packet for a call applied to the present invention;

3b is a view showing a packet for measuring the call quality applied to the present invention,

4 is a diagram showing a start / end PCM pattern applied to the present invention;

5 is a first embodiment showing a method for measuring call quality in a mobile communication system according to the present invention;

6 is a second embodiment showing a method of measuring call quality in a mobile communication system according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100: VAD part, 110: encoder part,

120: test vector generation unit, 130: first switching unit,

140: packet detection switching unit.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the apparatus and method for measuring call quality in a mobile communication system according to the present invention will be described.

Fig. 2A is a block diagram of a first embodiment showing an apparatus for measuring call quality in a mobile communication system according to the present invention, which is located in a vocoder of a control station so as to perform a loopback test of a radio section.

As shown in FIG. 2A, the presence / absence of the caller's voice is detected and the rate of the detected voice (eg, rates 1, 1/2, 1/4) is encoded and transmitted. A voice activity detection (VAD) unit 100 for determining a signal, an encoder unit 110 for encoding a voice output from the VAD 100, a pre-stored voice packet, and a data packet are generated. A test vector generator 120, a voice rate 1, 1/2, and 1/4 output from the VAD 100 and data output from the test vector generator 120. A first switching unit 130 for switching the packet rate 1/8 to the base station of the radio section, and a voice rate of 1 and 1/2 when the caller continues to speak in the signal transmitted from the base station. Packet detection switching unit 140 for switching test packets of rates 1 ', 1/2', 1/4 ', and 1/8' when not talking to 1/4, and the packet detection switching unit ( Decode unit 150 that receives and decodes the voice rates 1, 1/2, and 1/4 outputted from 140, and detects the PCM at the voice rate output from the decoder 150, switches, and sends them to the exchange. PCM detection switching unit 160, the test packet output from the packet detection switching unit 140, 1 ', 1/2', 1/4 ', 1/8' and the output from the decoding unit 150 A test vector detector 170 for detecting a test vector by receiving voice packets 1 ', 1/2', 1/4 ', and 1/8', and a test output from the test vector generator 120 A synchronizer 180 for correcting an error in a starting position due to a transmission delay between a vector and a test vector detected by the test vector detector 170, and from the synchronizer 180; It consists in that force data to the measurement section 190 for performing the desired quality measurement.

FIG. 2B is a block diagram of a second embodiment showing an apparatus for measuring call quality in a mobile communication system according to the present invention, and is located in a vocoder of a control station so as to perform a loopback test of a wired section.

As shown in FIG. 2B, the decoder 200 decodes voice packet rates 1, 1/2, and 1/4, and the test vector generator 210 generates a test vector by receiving a data packet rate of 1/8. ) And a second packet for switching the voice packet rates 1, 1/2, and 1/4 outputted from the decoder 200 and the data packets 1/8 outputted from the test vector generator 210 to be output to the exchange. A switching unit 220, a flag pattern check switching unit 230 for receiving and switching the data transmitted from the exchange, and an encoding unit for encoding the audio output from the flag pattern check switching unit 230 240, a test vector detector 250 for detecting a test vector from the voice output from the flag pattern check switching unit 230, and a test vector output from the test vector generator 210; The test vector detector 2 A synchronization unit 260 for correcting an error in a starting position due to a transmission delay between the test vectors detected in 50), and a measurement unit 270 for performing a desired quality measurement on data output from the synchronization unit 260. do.

Referring to the operation of the call quality measurement apparatus in the mobile communication system configured as described above are as follows.

First, as shown in FIG. 2A, in the case of the call release state in the wireless section, the test vector generator 120 generates a pre-stored vector (voice packet, data packet, etc.), that is, the base station direction, that is, the base station. (Not shown) / Mobile station (not shown).

Subsequently, the base station or the mobile station retransmits the voice packet and the data packet to the test vector detector 170 of the control station (not shown) at a predetermined position.

In this case, the test vector detector 170 reads and stores the data.

The synchronizer 180 corrects the starting position error due to the transmission delay between the original (existing) test vector and the detected test vector.

Accordingly, the measuring unit 190 measures the desired call quality.

In particular, the type of the test vector and the position of detecting the test vector vary according to the call quality measurement method. For example, if you want to measure the call quality over the radio, FER, test vectors should be sent in packet form, and loopbacked packet detection should be done at the decoding end of the vocoder.

If you want to measure the call quality with SQM, you have to send the test vector PCM in the form of encoded packet, and compare the packet with the original PCM by detecting the PCM recovered from the decoding section of the vocoder and retransmitting the packet that was looped back at a predetermined point. Should be.

As shown in Figure 2b can be similar to the quality evaluation for the wired section. The test vector generator 210 generates packet data in the case of FER measurement and PCM data in the case of SQM measurement, and transmits the packet data to the wired section to loop back at a desired point of the wired section.

Then, the retransmitted data may be detected by a Rx vector detector (not shown) of the serial input stage and compared with the original data.

On the other hand, the case of the call ongoing (calling) on-line in the wireless section is as follows.

Here, it is assumed that the basic principle of the proposed method is that the caller generally speaks about 30% of the time. Therefore, all of the vocoders used in the actual digital mobile communication system use the variable rate voice coder using these statistical characteristics.

In the method of operation, as shown in FIGS. 3A to 3B, a section in which voice is present is transmitted at Rate 1, and a section in which voice is absent is transmitted at Rate 1/8.

And there is a rate 1/2 or 1/4 for the natural transition of these two intervals.

As such, the VAD unit 100 of FIG. 2A plays a role of determining whether or not a voice is encoded and transmitted at a rate by determining a presence / absence of voice during a call.

In this case, at rates 1, 1/2, and 1/4, the actual caller's voice is transmitted, and at rate 1/8, the test vector is transmitted. To explain this in more detail, it is assumed that a call is in between subscribers.

At this time, when the subscriber to the wired section side talks, the VAD unit 100 determines the rate 1 and transmits a voice packet to the wireless subscriber side.

And, if you do not continue to speak during the call, the VAD unit 100 will determine the rate 1/8, where the test vector generator 120 rate 1 ', 1/2', 1/4 ', 1/8 A test vector (packet) is generated to replace the rate 1/8 packet with this packet.

In this manner, during the call, the original call voice packet and the test packet are transmitted while being switched according to the determined rate of the VAD unit 100.

At the preset loopback point, the two packets are divided and passed through the original processing in the case of the voice packet of the caller, and looped back in the case of the test packet and retransmitted. The retransmitted packet is measured in the packet detection switching unit 140 in the case of FER, and the PCM detection switching unit 160 in the case of SQM, in the case of FER, which is to be measured in the same manner as described in the method for measuring the quality of the radio section when the call is released. After each switch and compensates for the error caused by the transmission delay, compare and measure the quality between the transmitted data and the looped back data.

Here, the distinction between the original voice packet and the test packet should be made.

That is, in the case of an existing packet, the preceding rake field is one of four types of 1, 1/2, 1/4, and 1/8, followed by pure voice or data packets. And the rest of the bits are RESERVED (usually zero).

In order to distinguish this from the test packet, a rate field is assigned a rate other than four types of rates of the existing voice packet, and the existing reserved bits are used as identification bits.

On the other hand, referring to Figure 2b, the sound quality evaluation method for the streamline section is similarly made. When the caller's words output through the wired section go out to PCM format, the rate information of the voice packet transmitted from the wireless subscriber is reported. If the rate is 1, 1/2, or 1/4, the decoded PCM information is transmitted and the rate 1 / If 8, the test vector generated by the test vector unit is transmitted.

At this time, the distinction between the PCM decoded the actual call speech and the test PCM for quality evaluation is shown in FIG. That is, a specific PCM pattern may be determined in advance, and one frame of the starting PCM pattern is transmitted before the start of the test PCM section, and then one frame of the ending PCM pattern is sent to inform the end after the test PCM is continuously sent.

The packet test for the wired section may proceed in the same way as described for the wireless section.

However, the method of measuring the call quality at the same time during the proposed call is performed only in the rate 1/8 section corresponding to about 70% of the total talk time, but there is a possibility of degrading the call performance.

There are many ways to compensate for this. One of them is that when the call quality measurement vector is detected at the loopback point, the noise may be inserted to compensate for the unnaturalness of the call.

Another thing to think about is that when the system is actually operated, the call quality may be poor, the call performance may be poor, and the call quality may be measured on-line in a timely manner.

5 is a flowchart illustrating a test vector caller as a first embodiment showing a method of measuring call quality in a mobile communication system according to the present invention.

As illustrated in FIG. 5, it is determined whether the rate is 1/8 in the presence / absence period of the voice.

As a result of the determination, if the rate is not 1/8, it is assumed that the voice rates are 1, 1/2, and 1/4 and data is transmitted.

As a result of the determination, if the rate is 1/8, the test vector is transmitted in the absence of speech.

Subsequently, the vector detector compares and measures the original data, determines whether the measurement is completed, and transmits data to the base station and the mobile station when the measurement is completed.

6 is a flowchart illustrating a test vector receiving side as a second embodiment showing a method of measuring call quality in a mobile communication system according to the present invention.

As shown in Figure 6, it is determined whether the data sent to the base station is a test vector.

If the result of the determination is not the test vector, the data is regarded as voice rate 1, 1/2, and 1/4, and data is transmitted.

As a result of the determination, if the test vector is detected, the test vector is detected as a section without speech.

Subsequently, the vector detector compares and measures the original data, determines whether the vector detection is completed, and if the detection is completed, synchronizes the starting position error due to the transmission delay between the original (existing) test vector and the detected test vector. Is carried out.

And, the measuring unit 190 measures the desired call quality.

As described above, the present invention has the effect of measuring call quality as well as during call release, in particular, during call progress.

In addition, subscribers whose quality is degraded during actual calls can analyze the degree of deterioration on the call channel by measuring the call quality in real time, and can be extended to improve the quality by using this result.

In addition, since the call quality measurement is handled by the control station vocoder by S / W, there is no additional cost burden due to capacity increase and the upgrade is easy.

Claims (4)

A Voice Activity Detection (VAD) unit for detecting presence / absence of a caller's voice and determining a rate of encoding and transmitting the detected voice; An encoding unit for encoding the voice output from the VAD; A test vector generation unit generating a pre-stored voice packet and a data packet; A first switching unit for switching the voice rates 1, 1/2, and 1/4 output from the VAD and the data packet rates 1/8 output from the test vector generation unit and transmitting them to a base station of a radio section; ; Voice rate 1, 1/2 when the caller continues to speak in the signal from the base station. A packet detection switching unit for switching test packets of rates 1 ', 1/2', 1/4 ', and 1/8' when not talking to 1/4; A decoder which receives and decodes voice rates 1, 1/2, and 1/4 output from the packet detection switching unit; A PCM detection switching unit which detects the PCM at the voice rate output from the decode unit and then switches the PCM to switch to the switch; Test packets 1 ', 1/2', 1/4 ', 1/8' outputted from the packet detection switching unit and voice packets 1 ', 1/2', 1/4 ', 1 outputted from the decoding unit A test vector detector for detecting a test vector by a '8'; A synchronizer for correcting an error of a start position due to a transmission delay between a test vector output from the test vector generator and a test vector detected by the test vector detector; Call quality measuring apparatus in the mobile communication system, characterized in that configured to measure the desired quality from the data output from the synchronization unit. A decode unit for decoding voice packet rates 1, 1/2 and 1/4; A test vector generation unit receiving a data packet rate of 1/8 to generate a test vector; A second switching unit for switching the voice packet rates 1, 1/2, and 1/4 outputted from the decode unit and the data packets 1/8 outputted from the test vector generator to be outputted to the exchange; A flag pattern check switching unit configured to receive and switch data transmitted from the exchange; An encoder for encoding the voice output from the flag pattern check switching unit; A test vector detector for detecting a test vector from the voice output from the flag pattern check switching unit; A synchronizer for correcting an error of a start position due to a transmission delay between a test vector output from the test vector generator and a test vector detected by the test vector detector; Call quality measuring apparatus in a mobile communication system, characterized in that configured to measure the desired quality from the data output from the synchronization unit. Determining whether a rate is 1/8 in the presence / absence of speech; If it is determined that the rate is not 1/8, the data is regarded as being 1, 1/2, 1/4; If the rate is 1/8, determining that there is no voice and transmitting a test vector; And comparing with the original data, determining whether the measurement is completed, and transmitting the data to the base station and the mobile station when the measurement is completed. Determining whether the data sent to the base station is a test vector; Transmitting data in consideration of a voice rate of 1, 1/2, or 1/4 if the test result is not the test vector; If it is determined that the test vector is a test vector, detecting a test vector as a section having no voice; Compare and measure the original data and determine whether the vector detection is completed. If the detection is completed, perform synchronization by correcting the starting position error due to the transmission delay between the original test vector and the detected test vector, and measure the call quality. Call quality measurement method in a mobile communication system, characterized in that it comprises a step.