JP2010010856A - Noise cancellation device, noise cancellation method, noise cancellation program, noise cancellation system, and base station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove noise components from a speech voice at high precision without necessity to mount a noise cancellation function on a mobile communication terminal. <P>SOLUTION: A terminal detection unit in a fixed range 35 detects circuits during voice communication, and detects other mobile communication terminals (lines) which exist in a fixed distance range for mobile communication terminals of noise elimination target lines out of a plurality of circuits during voice communication. A sound data collection unit 36 collects sound data of the other mobile communication terminals detected by the terminal detection unit in the fixed range 35. A sound data analysis-noise component discrimination unit 37 analyzes the sound data collected by the sound data collection unit 36, detects common frequency components, and discriminates the frequency components as a noise component. A noise component elimination unit 38 subtracts the noise component from the voice data of each noise elimination target line. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides, for example, a noise canceling device, a noise canceling method, a noise canceling program, a noise canceling system, and a base that remove ambient noise components from the voice of a call when a voice call is performed on a mobile phone terminal or the like. About the station.

  A voice call at a mobile phone terminal, which is a typical example of a mobile communication terminal, is obtained by capturing a call voice generated by a human by a microphone mounted on the terminal and sending the call voice signal to a base station and a mobile phone network. This is done by transmitting to the terminal of the other party via the call.

  However, the microphone captures unnecessary surrounding sounds (that is, environmental noise) in addition to the voices uttered by the person who is talking. For this reason, the surrounding environmental noise other than the call voice is also transmitted to the other party, and a situation frequently occurs where the environmental noise interferes with the call.

  Conventionally, a technology for solving the problem of environmental noise by installing a noise canceling function in a mobile phone terminal is known. This noise canceling function is a function that determines a signal component that matches a specific condition in the audio signal input from the microphone as a noise component and removes the noise component from the audio signal. . That is, since the removal of the noise component is performed in the mobile phone terminal, the audio signal after the removal of the noise component is sent to the base station side and the terminal on the other side of the call via the base station.

  In addition, for example, in Japanese Unexamined Patent Application Publication No. 2002-169599 (Patent Document 1), an input audio signal is divided into predetermined time unit frames, and the frames are further divided into predetermined frequency bands. A noise suppression method that performs noise suppression processing for each divided band is disclosed. In the noise suppression method described in this publication, the band-by-band gain value of a frame determined to be an audio frame can be smaller than the band-by-band gain value of a frame determined to be a noise frame. Noise can be suppressed by setting the gain value.

Japanese Patent Laying-Open No. 2002-169599 (FIG. 2)

  By the way, in order to remove noise as described above, a mobile phone terminal equipped with a noise canceling function is required. However, if a noise cancellation function is installed, an increase in terminal price is unavoidable, and the execution of noise cancellation processing increases the processing load in the terminal.

  Furthermore, when the mobile phone terminal is equipped with a noise cancellation function, in order to actually use the function, the user must operate the mobile phone terminal himself and do not perform the setting to enable the noise cancellation function. Then, a very complicated operation is required for the user.

  In addition, the conventional noise cancellation function detects a noise component from an input voice signal of a built-in microphone of a mobile phone terminal as described above. As described above, it is difficult to say that noise component detection using only the input sound signal of the built-in microphone has sufficient accuracy, and as a result, noise cancellation accuracy tends to be insufficient.

  The present invention has been proposed in view of such a situation, and it is not necessary to mount a noise canceling function in a mobile communication terminal, and a noise canceling device capable of removing a noise component with high accuracy from a call voice, An object of the present invention is to provide a noise cancellation method, a noise cancellation program, a noise cancellation system, and a base station.

  In the present invention, noise cancellation processing is performed by at least a terminal within a certain range, a sound signal collection unit, a sound signal analysis / noise component determination unit, and a noise component removal unit. Here, the in-range terminal detection unit detects a line that is in a connected state, and from a plurality of lines in the connected state, a fixed distance range with respect to the communication terminal of the noise removal target line Detect lines of other communication terminals existing in the network. The sound signal collection unit collects at least the sound signals of the lines of other communication terminals detected by the terminal detection unit within a certain range. The sound signal analysis / noise component determination unit analyzes the sound signal collected by the sound signal collection unit, detects a common signal component, and determines the common signal component as a noise component. The noise component removal unit removes the signal component determined as the noise component by the sound signal analysis / noise component determination unit from the sound signal of the noise removal target line. Thereby, this invention has solved the above-mentioned subject.

  That is, according to the present invention, another communication terminal within a certain distance range is detected from the communication terminal of the line being connected and the noise removal target line. It is considered that the sound signals on the lines of other communication terminals within these fixed distance ranges contain substantially the same noise component as included in the sound signals on the noise removal target line. Therefore, if noise components obtained from the sound signals on the lines of other communication terminals within the fixed distance range are removed from the sound signals on the noise removal target line, noise cancellation becomes possible.

  In the present invention, the base station detects a sound signal of another communication terminal that is connected to the line and is within a fixed distance range from the terminal of the noise removal target line, and the noise component obtained from the sound signal is the noise removal target. Removed from the sound signal on the line. As a result, in the present invention, it is not necessary to mount a noise cancellation function in the communication terminal itself, and it is possible to remove noise components from the audio signal with high accuracy.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In the following description, a mobile communication line such as a mobile phone line is given as an example of the communication line according to the present invention, and a mobile communication terminal such as a mobile phone terminal is given as an example of the communication terminal according to the present invention. ing. Therefore, in this embodiment, the base station is a mobile base station of a mobile phone network. Of course, what was mentioned by this embodiment is an example to the last, and it cannot be overemphasized that this invention is not limited to this example.

[System configuration example of the embodiment of the present invention]
FIG. 1 shows a schematic configuration of a communication system according to an embodiment of the present invention.

  In FIG. 1, it is assumed that mobile communication terminals 1, 2, 3, 4 exist in the area of the base station 10 and are under the management of the base station 10. In this embodiment, among the mobile communication terminals 1, 2, 3, and 4 in the area of the base station 10, for example, the lines of the mobile communication terminals 1, 2, and 3 are in a connected state and a voice call is in progress. Suppose that Further, among the mobile communication terminals 1, 2, and 3 during the voice call, in particular, the mobile communication terminal 1 is, for example, a mobile communication terminal 5 that exists in the area (under management) of another base station 13. And a voice call. On the other hand, it is assumed that the mobile communication terminals 2 and 3 are in a voice call with another terminal not shown. In addition, it is assumed that the mobile communication terminals 1, 2, 3, and 4 in the base station 10 area exist in the same noise environment as in an exhibition hall or an entertainment facility, for example. Note that the base station 10 and the base station 13 may be base stations of the same mobile phone network, or may be base stations of different mobile phone networks. In the example of FIG. 1, the mobile phone network 11 of the base station 10 and the mobile phone network 12 of the base station 13 are different mobile phone networks.

[Configuration Example of Mobile Communication Terminal of the Present Embodiment]
FIG. 2 shows a schematic configuration of a mobile phone terminal which is a mobile communication terminal according to an embodiment of the present invention.

  In FIG. 2, a communication antenna 21 transmits and receives signal radio waves for communication such as telephone calls and e-mails, and a terminal communication circuit 20 performs frequency conversion, modulation, demodulation, and the like of these transmission / reception signals.

  The speaker 27 is a speaker for receiving voice, a ringer (ringing tone), a sound output speaker such as an alarm sound, etc. provided in the mobile phone terminal. The microphone 28 is a microphone for transmitting and collecting external sound. The voice processing unit 26 performs various processes related to voice such as call voice data and reproduced music.

  The display unit 23 includes a display device such as a liquid crystal display or an organic EL (ElectroLuminescent) display, and a display drive circuit for the display.

  The terminal memory unit 25 stores, for example, an OS (Operating System) program, a control program for the terminal control unit 22 to control each unit, other various application programs, and various data, and a work area of the terminal control unit 22 As needed, store data.

  The operation unit 24 is a key device such as a numeric keypad, a speech key, an end / power key, and a key device provided on the casing of the mobile phone terminal, and when the key device is pressed. An operation signal generator for generating the operation signal.

  The terminal control unit 22 includes a CPU (Central Processing Unit), and performs control of each unit of the mobile phone terminal according to the present embodiment, calculation and control of various signal processing, and the like.

  In addition, although illustration is abbreviate | omitted in FIG. 2, the mobile communication terminal of this embodiment is also provided about each component provided in a general mobile telephone terminal.

[Schematic operation and configuration example of a base station according to the present invention]
FIG. 3 shows a schematic configuration of the base station according to the embodiment of the present invention.

  In FIG. 3, a communication antenna 32 transmits / receives signal radio waves to / from a mobile communication terminal (mobile phone terminal), and a base station radio communication circuit 31 performs frequency conversion, modulation, demodulation, etc. of the transmitted / received signal. Do.

  The base station memory unit 33 stores, for example, an OS program, a control program for the base station control unit 30 to control each unit, a noise cancellation program according to the present invention, a signal processing program, and various other data. Data is stored at any time as a work area of the base station control unit 30. Note that the noise cancellation program according to the present invention stored in the base station memory unit 33 is stored via a disk-shaped recording medium, an external semiconductor memory, or the like, or stored via a cable or wirelessly through an external interface. It may be.

  The base station control unit 30 is composed of a CPU (Central Processing Unit) and performs control of each part of the base station of this embodiment, calculation and control of various signal processing, and the like.

  The within-determined range terminal detection unit 35 is a mobile communication terminal (that is, a mobile communication terminal that is within a certain distance from each other among mobile communication terminals of a plurality of lines that are under the control of the base station and are engaged in a voice call) The line of each mobile communication terminal) is detected. The details of the detection processing of each mobile communication terminal within a certain distance range will be described later.

  The sound data collection unit 36 collects call voice data of all mobile communication terminals that are under the control of the base station and that are in a voice call and exist within a certain distance range. That is, the sound data collection unit 36 collects sound data collected by the microphones of the respective mobile communication terminals and transmitted from the mobile communication terminals to the base station as call voice data.

  The sound data analysis / noise component determination unit 37 analyzes the collected sound data by the sound data collection unit 36, obtains a signal component that can be used for noise removal, and determines the signal component as a noise component. The details of the noise component determination process will be described later.

  The noise component removing unit 38 subtracts the noise component from the sound data of each mobile communication terminal existing within the certain distance range. Thereby, the noise component removing unit 38 obtains sound data from which noise components have been removed from the sound data of each mobile communication terminal existing within the certain distance range.

  Then, the base station uses the sound data from which the noise component has been removed by the noise component removing unit 38 as voice data transmitted from each mobile communication terminal during the voice call to each call partner. That is, clear call voice data from which ambient environmental noise components are removed (noise cancellation) is transmitted to each call partner.

  Note that the in-range terminal detection unit 35, the sound data collection unit 36, the sound data analysis / noise component determination unit 37, and the noise component removal unit 38 may be formed by software by executing the noise cancellation program of the present invention. However, it may be configured as hardware.

[Operation sequence of the entire system]
FIG. 4 shows a schematic operation sequence example of noise cancellation processing by the base station of this embodiment.

  In the example of FIG. 4, the line of the mobile communication terminal 1 is cited as a target line for noise cancellation processing, and an example of the operation sequence of the entire system when the base station 10 performs noise cancellation on the voice data of the line is shown. . In the following description, the target line for noise cancellation processing is described as being limited to the line of the mobile communication terminal 1, but the base station of the present invention is subject to noise cancellation processing for all the lines under its management. Can be treated as a line.

  When the base station 10 receives a voice call start request (T1) from the mobile communication terminal 1 through the base station radio communication circuit 31, the base station control unit 30 starts the operation for noise cancellation processing of the present embodiment. To do. At this time, in the mobile communication system as a whole, a voice call is started between the mobile communication terminal 1 and the mobile communication terminal 5.

  Next, in response to the start of the voice call between the mobile communication terminal 1 and the mobile communication terminal 5, the base station 10 receives all the mobile communication terminals (in FIG. 1) under the control of the base station. In the example, it is confirmed whether the terminals 1, 2, 3, 4) are in a voice call state. And the base station 10 is the mobile communication terminal 2 which exists in the fixed distance range with respect to the said mobile communication terminal 1 and the said terminal 1 among the mobile communication terminals in all the voice call states. 3 is requested (T2) for sound data collected by the microphone of each terminal. At this time, each mobile communication terminal 1, 2, 3 transmits the sound data collected by the microphone of each terminal to the base station 10 as a response to the transmission request (T2) of the sound data (T3 ) In the sequence of FIG. 4, an example is given in which a transmission request (T2) of sound data and a response (T3) are made. However, if each terminal is already in a voice call state at this time, It is possible to omit processing of the request (T2) and the response (T3).

  Next, as described above, the base station 10 collects the voice data of the mobile communication terminals 1, 2, and 3 during the voice call and within a certain distance range by the sound data collection unit 36, The sound data analysis / noise component determination unit 37 analyzes the collected sound data and performs noise component determination processing (T4). Furthermore, the sound data analysis / noise component determination unit 37 is a signal having a common frequency and a common phase component (same time axis component) from sound data collected from each terminal within a certain distance range during a voice call. The component is extracted, and the signal component is determined as common environmental noise under the management of the base station.

  Then, the base station 10 removes the environmental noise component (T6) by the noise component removal unit 38 from the call voice signal transmitted (T5) from the mobile communication terminal 1. The call voice signal after the noise removal is transmitted to the base station 13 (T7), and is transmitted to the mobile communication terminal 5 of the call partner via the base station 13.

[Processing flow of base station according to the present invention]
Hereinafter, the sound data collection, analysis, noise component determination, and noise removal processing as described above will be described in the base station 10 according to the embodiment of the present invention with reference to the flowchart shown in FIG. Note that the example of FIG. 5 shows a flowchart when the base station control unit 30 is mainly executed by executing the noise cancellation program of the present invention to control each unit. Of course, the terminal detection unit 35, the sound data collection unit 36, the sound data analysis / noise component determination unit 37, and the noise component removal unit 38 may be formed in software by executing the noise cancellation program of the present invention. It is included in this flowchart.

  When the mobile communication terminal 10 starts a voice call as in the example of FIG. 4, the base station control unit 30 starts the processing of the flowchart of FIG.

  After starting the processing of the flowchart of FIG. 5, first, the base station control unit 30 monitors the network under the management of the base station through the base station radio communication circuit 31 as the processing of step S1, and the mobile communication terminal 1. Check whether there is a line other than 1 that has a voice call. If the base station control unit 30 determines in step S1 that there is another line in a voice call, the base station control unit 30 proceeds to step S2, and if it determines that there is no other line in a voice call, The process of the flowchart is terminated.

  When the processing proceeds to step S2, the base station control unit 30 causes the terminal detection unit 35 within a certain range to confirm the position information of the mobile communication terminal 1, and in addition, the mobile communication terminal performing a voice call. Confirm the location information. At this time, the base station control unit 30 performs other mobile communication during a voice call within a predetermined distance range from the position of the mobile communication terminal 1 by the in-range terminal detection unit 35 as a process of step S3. Determine whether a terminal exists. A specific example of the process of determining the position of each terminal and determining whether it is within a certain distance range will be described later. When the base station control unit 30 determines that there is another mobile communication terminal that is performing a voice call within a certain distance range, the base station control unit 30 proceeds to step S4, and when it is determined that there is no other mobile communication terminal. Ends the process of the flowchart.

  In step S4, the base station control unit 30 uses the sound data collection unit 36 to obtain the audio signal waveform data of all the lines in the mobile communication terminal 1 and other mobile communication terminals within the fixed distance range. Let them collect.

  Then, the base station control unit 30 causes the sound data analysis / noise component determination unit 37 to determine a location where the audio signal waveform components match on two or more lines from the collected audio signal waveform data, and the waveform of the matching location Ingredients are extracted. The audio signal waveform components can be matched by looking at the match between the frequency component and the phase component (time axis component). A specific example of the coincidence determination process of the frequency component and phase component (time axis component) of the same time will be described later.

  Here, the voice signal waveform of the mobile communication terminal 1 is, for example, a waveform as shown in FIG. 6, and the mobile communication terminal 2 that is in a certain distance range from the mobile communication terminal 1 during the voice call. Assume that the audio signal waveform of the terminal 3 is such as shown in FIGS. In this case, the sound data analysis / noise component determination unit 37 obtains a location where the audio signal waveform components in two or more lines match among the audio signal waveforms of each line in FIGS. The signal waveform component at the selected location is extracted. That is, according to the examples of FIGS. 6 to 8, for example, the signal waveform components of the two lines shown in FIGS. 7 and 8 are substantially the same, whereas the audio signal waveform of FIG. For example, an audio signal waveform component m at the time of a human call is superimposed on the signal waveform of FIG. Therefore, in this case, the sound data analysis / noise component determination unit 37 shows the signal waveforms excluding the voice signal waveform component m during the person's call, specifically, the signal waveform components of FIGS. 7 and 8 in FIG. Thus, it is extracted as a waveform component.

  Next, the base station control unit 30 advances the processing to step S5, uses the signal waveform component extracted in step S4 as a noise component, and the noise component removal unit 38 causes the speech signal waveform and time of the mobile communication terminal 1 to be transmitted. After matching the axis reference, the noise component is subtracted from the call voice signal waveform. That is, in this case, the noise component removing unit 38 subtracts, for example, the waveform component (noise component) shown in FIG. 9 from the audio signal waveform of the mobile communication terminal 1 shown in FIG. . As a result, the noise component removal unit 38 obtains the audio signal waveform M after the noise component removal as shown in FIG.

  Then, the base station control unit 30 sends the call voice signal after the ambient noise has been removed by the noise component removal unit 38 from the mobile phone communication circuit 34 to the mobile phone network 11 as the process of step S6. To the mobile communication terminal 5 of the call partner.

  Thereafter, the base station control unit 30 determines whether or not the voice communication of the mobile communication terminal 1 is continued as the process of step S7, and returns the process to step S1 when continuing, while the voice call is continued. When this is not the case, the process of this flowchart is terminated. That is, the base station control unit 30 continues the voice call of the mobile communication terminal 1, and there is a line of another mobile communication terminal that is making a voice call within a certain distance range of the terminal 1. As long as this is done, the processing of this flowchart is repeated.

[Determination method of mobile communication terminals existing within a certain distance range]
Hereinafter, detailed processing when determining whether each mobile communication terminal is within a certain distance range in the certain range terminal detecting unit 35 of the base station 10 will be described with reference to FIGS. 11 and 12.

  As shown in FIG. 11, the in-range terminal detection unit 35 time-divides the audio signal waveform of each line under the control of the base station at a predetermined time interval, and time-divides each time slot t1, For each t2, t3,..., a process for determining whether or not the mobile communication terminal of each line is within a certain distance range is performed. In the examples of FIGS. 11 and 12, a case where there are five lines A to E as each line under the control of the base station. In the example of FIGS. 11 and 12, the target line for noise cancellation processing is described as line A.

  That is, in the case of this example, the in-range terminal detection unit 35 time-divides each voice signal waveform of each of the lines A to E on the same time axis, and uses the signal component of each time slot of each line, A determination process is performed as to whether or not each mobile communication terminal of line B to line E is within a certain distance from the mobile communication terminal of line A subject to the noise cancellation process.

  Here, the determination process will be described by taking an audio signal waveform in the section of the time slot t3 as an example.

  The fixed-range terminal detection unit 35 decomposes the signal waveform in the section of the time slot t3 for each of the lines A to E into frequency components. FIG. 12 shows an example of frequency components and amplitudes of the lines A to E after the signal waveform of the time slot t3 is expanded into frequency components.

  Next, the in-range terminal detection unit 35 divides the frequency component into a voice band obtained from a person's voice and a non-voice band other than that. In the example of FIG. 12, the voice band is divided into a voice band based on a person's call voice, a non-voice band lower than the voice band, and a non-voice band higher than the voice band.

  Next, the in-range terminal detection unit 35 compares the amplitudes of the frequency components with respect to several frequency points as indicated by arrows in FIG. In the example of FIG. 12, for example, ten frequency points are extracted as indicated by arrows in the figure. That is, the in-range terminal detection unit 35 obtains an amplitude difference between the frequency components of the noise cancellation processing target line A for all the 10 frequency points, and the amplitude differences are within a predetermined threshold ( For example, a line that is within ± 30% is obtained.

  Then, the within-range terminal detection unit 35 exists within a certain distance range from the mobile communication terminal of the line A whose noise difference is within the predetermined threshold from the mobile communication terminal of the noise cancellation processing target line A. Detect as a connected terminal. In the case of the example of FIG. 12, since the amplitude difference of the line B, the line C, and the line D is within ± 30%, the in-range terminal detection unit 35 is connected to the terminals of the lines B, C, and D. Is present within a certain distance range from the terminal of line A. On the other hand, since the amplitude difference is out of ± 30% for the terminal on line E, the in-range terminal detection unit 35 indicates that the terminal on line E is within a certain distance from the terminal on line A. Judge that there is no.

  In addition, when the mobile communication terminals of each line A to line E are equipped with a GPS (Global Positioning System) device and the position information from the GPS device is set to be provided to the base station, The terminal within the fixed range detection unit 35 may determine whether or not each terminal is within a fixed distance range based on the GPS position information obtained from the terminals of the respective lines A to E.

[Noise component judgment method]
Next, the sound data analysis / noise component determination unit 37 of the base station 10 obtains a signal component that can be used for noise removal from the signal waveform component of each terminal within a certain distance range, and determines that the signal component is a noise component. The detailed processing at this time will be described with reference to FIG.

  The sound data analysis / noise component determination unit 37 generates the sound signal waveforms of the lines B, C, and D determined by the above-described fixed range terminal detection unit 35 within the fixed distance range in the same manner as in FIG. Each of them is time-divided, and the signal waveform in each time slot is further decomposed into frequency components. In addition, the sound data analysis / noise component determination unit 37 divides the frequency component after being developed into the frequency component into a voice band based on a person's call voice and a non-voice band other than that as described above.

  Here, the determination process of the noise component in the sound data analysis / noise component determination unit 37 will be described by taking the sound signal waveform in the section of the time slot t6 as an example. FIG. 13 shows an example of frequency components of the lines B, C, and D and their amplitudes after the signal waveform of the time slot t6 is expanded into frequency components.

  The sound data analysis / noise component determination unit 37 extracts several frequency points as indicated by arrows in FIG. 13 from the voice band of the person's call voice, the frequency components of these frequency points, and a predetermined frequency point. Amplitude values (hereinafter referred to as audio signal determination limit values) are compared. In the case of the example in FIG. 13, the sound data analysis / noise component determination unit 37 extracts, for example, five frequency points as indicated by arrows in the figure, and the amplitude value of the frequency component at each of these five frequency points. And the audio signal determination limit value are compared.

  Further, the sound data analysis / noise component determination unit 37, when any one of the amplitude values of the frequency components at each frequency point exceeds the audio signal determination limit value, the voice signal of the person's call is transmitted to the line. Judged to be included. That is, in the example of FIG. 13, since the amplitude value of the frequency component of the line C exceeds the voice signal determination limit value, the sound data analysis / noise component determination unit 37 includes the call voice signal in the line C. It is judged that

  Next, the sound data analysis / noise component determination unit 37 excludes the signal component of the line C from the candidate signal components that can be used for noise removal. That is, the reason why the signal component of the line C is excluded is that it is not preferable to use a signal component that is considered to contain a voice signal based on a person's call voice for noise removal.

  Then, the sound data analysis / noise component determination unit 37 calculates the amplitude average of the signal components of the remaining lines B and D excluding the line C, and the noise component removal unit uses the signal component after the amplitude average as a noise component. Send to 38.

[Summary]
As described above, according to the present embodiment, the base station detects a plurality of terminals that are in a voice call and within a certain distance range from each other among a plurality of mobile communication terminals under the control of the base station, A noise component of the surrounding environment is obtained from the call voice signal of each terminal, and the noise component is removed from the call voice signal.

  That is, according to the present embodiment, for example, the base station can detect the specific environmental noise occurring in a certain range of places where many people gather, such as an exhibition hall or an amusement facility, with high accuracy. Since the base station can remove the environmental noise from the call voice signal, a high-quality call voice signal is sent to the call partner terminal.

  Thus, according to this embodiment, since the noise component is detected and removed by the base station, it is not necessary for the mobile communication terminal to be individually equipped with a noise cancellation function. Further, since it is not necessary to mount a noise cancellation function in the mobile communication terminal, the user of the terminal does not need to perform an operation such as setting the noise cancellation function to be effective.

  The above description of the embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made according to the design or the like as long as the technical idea according to the present invention is not deviated.

It is a figure which shows schematic structure of the communication system of embodiment of this invention. It is a block circuit diagram which shows schematic structure of the mobile telephone terminal which is a mobile communication terminal of this invention embodiment. It is a block circuit diagram which shows schematic structure of the base station of this invention embodiment. It is a schematic operation | movement sequence diagram of the noise cancellation process by the base station of this embodiment. It is a flowchart of sound data collection, analysis, noise component determination, and noise removal processing in the base station of the present embodiment. It is a wave form diagram which shows an example of the audio | voice signal waveform of the mobile communication terminal used as the object line of a noise cancellation process. It is a wave form diagram which shows an example of the audio | voice signal waveform of the other mobile communication terminal within the fixed distance range from the mobile communication terminal of a noise cancellation process target line during a voice call. It is a wave form diagram which shows an example of the audio | voice signal waveform of the further another mobile communication terminal within the fixed distance range from the mobile communication terminal of a noise cancellation process target line during a voice call. FIG. 9 is a waveform diagram illustrating an example of a signal waveform extracted as a noise component from the signal waveform components of FIGS. 7 and 8. FIG. 10 is a waveform diagram showing an example of an audio signal waveform after the noise component of FIG. 9 is removed from the audio signal waveform of FIG. 6. It is a figure used for description of each time slot which time-divided each voice signal waveform of each line under management in a base station. FIG. 11 shows an example of frequency components and amplitudes of each line after the signal waveform of time slot t3 in FIG. 11 is expanded into frequency components, and the frequency used to explain whether or not each mobile communication terminal is within a certain distance range. -It is an amplitude characteristic figure. FIG. 11 shows an example of frequency components and amplitudes of each line after the signal waveform of time slot t6 in FIG. 11 is expanded into frequency components, and signal components that can be used for noise removal from the signal waveform components of each terminal within a fixed distance range. It is a figure used for description of the noise component determination at the time of calculating | requiring.

Explanation of symbols

  1-5 Mobile communication terminal (mobile phone terminal), 10, 13 base station, 11, 12 mobile phone network, 20 terminal communication circuit, 21 communication antenna of mobile communication terminal, 22 terminal control unit, 23 display unit, 24 Operation unit, 25 Terminal memory unit, 26 Audio processing unit, 27 Speaker, 28 Microphone, 30 Base station control unit, 31 Base station radio communication circuit, 32 Base station communication antenna, 33 Base station memory unit, 34 Mobile phone network communication Circuit, 35 within-range terminal detection unit, 36 sound data collection unit, 37 sound data analysis / noise component determination unit, 38 noise component removal unit

Claims (11)

While detecting a line that is in a connected state, a line of another communication terminal that is within a certain distance range from a plurality of lines in the above-mentioned connected state to a communication terminal that is a noise removal target line. A terminal detection unit within a certain range to detect,
A sound signal collection unit that collects sound signals of lines of other communication terminals detected by the terminal detection unit within the certain range;
A sound signal analysis / noise component determination unit that analyzes the sound signal collected by the sound signal collection unit to detect a common signal component and determines the common signal component as a noise component;
A noise component removing unit that removes the signal component determined to be a noise component by the sound signal analyzing / noise component determining unit from the sound signal of the noise removal target line;
A noise canceling device.   The in-range terminal detection unit divides a sound signal on the connected line into a voice signal component and a non-voice signal component, and removes the non-voice signal component of the sound signal on the connected line and the noise. The noise canceling apparatus according to claim 1, wherein a line whose difference between the sound signal and the non-voice signal component on the target line is within a predetermined threshold is detected as the line of the other communication terminal.   The in-range terminal detection unit decomposes the sound signal on the connected line into frequency components for each time slot at a predetermined time interval, and converts the frequency components for each time slot into audio frequency band components and non-speech The noise cancellation apparatus according to claim 2, wherein the difference is obtained for the non-speech frequency band component separately from the frequency band component.   The terminal within a certain range detects position information of the communication terminal of the connected line, and exists within a certain distance range with respect to the communication terminal of the line for noise removal based on the position information. The noise canceling apparatus according to claim 1, wherein a line of another communication terminal is detected.   The sound signal analysis / noise component determination unit divides the sound signal collected by the sound signal collection unit into a sound signal component and a non-sound signal component, compares the sound signal component with a predetermined limit value, The noise canceling device according to claim 1, wherein a sound signal component whose sound signal component is within the predetermined limit value is determined as a noise component.   The sound signal analysis / noise component determination unit decomposes the sound signal collected by the sound signal collection unit into frequency components for each time slot at a predetermined time interval, and converts the frequency component for each time slot into a sound frequency band component. The noise canceling apparatus according to claim 5, wherein the audio frequency band component is compared with the predetermined limit value separately for the non-voice frequency band component.   The noise cancellation apparatus according to claim 6, wherein the sound signal analysis / noise component determination unit determines a sound frequency band component after averaging a plurality of sound frequency band components within the predetermined limit value as the noise component. The within-range terminal detection unit detects a line that is in a connected state and exists within a certain distance range from the plurality of lines that are in the above-mentioned connected state to the communication terminal of the noise removal target line. Detecting a line of another communication terminal to perform,
A sound signal collecting unit collecting a sound signal of a line of another communication terminal detected by at least the terminal within a certain range;
A sound signal analysis / noise component determination unit that analyzes the sound signal collected by the sound signal collection unit to detect a common signal component, and determines the common signal component as a noise component;
A step of removing a signal component determined to be a noise component by the sound signal analysis / noise component determination unit from a sound signal of the noise removal target line by a noise component removal unit;
A noise canceling method. While detecting a line that is in a connected state, a line of another communication terminal that is within a certain distance range from a plurality of lines in the above-mentioned connected state to a communication terminal that is a noise removal target line. A terminal detection unit within a certain range to detect,
A sound signal collection unit that collects sound signals of lines of other communication terminals detected by the terminal detection unit within the certain range;
A sound signal analysis / noise component determination unit that analyzes the sound signal collected by the sound signal collection unit to detect a common signal component and determines the common signal component as a noise component;
As a noise component removal unit that removes the signal component determined as the noise component by the sound signal analysis / noise component determination unit from the sound signal of the noise removal target line,
A noise cancellation program that makes the computer work. A base station under control of multiple lines,
A plurality of communication terminals connected to other terminals based on management by the base station, and
The base station detects a line that is in a connected state and, from among a plurality of lines that are in the connected state, another communication terminal that is within a certain distance range with respect to the communication terminal of the noise removal target line , Collect the sound signal of the line of the other detected communication terminal, analyze the collected sound signal, determine the common signal component detected as a noise component, and determine the noise component Removing the signal component from the sound signal of the noise removal target line,
Noise cancellation system. Detects a line that is in a connected state and, from among the plurality of lines that are in the above-mentioned connected state, another mobile communication that exists within a certain distance range with respect to the mobile communication terminal of the noise removal target line A terminal detection unit within a certain range for detecting the terminal line;
A sound signal collecting unit that collects a sound signal of a line of another mobile communication terminal detected by at least the terminal within a certain range;
A sound signal analysis / noise component determination unit that analyzes the sound signal collected by the sound signal collection unit to detect a common signal component and determines the common signal component as a noise component;
A noise component removing unit that removes the signal component determined to be a noise component by the sound signal analyzing / noise component determining unit from the sound signal of the noise removal target line;
Base station with

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