JP2008236768A - Alarm device and alarm generating method used for it, and its program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alarm device that can easily detect interference caused in a wireless communication system and provide a guide to exclude deterioration in communication quality due to the interference. <P>SOLUTION: A band selection circuit 2 selects a signal including a band used by a wireless communication system that is a target from a radio wave received by a reception antenna 10 on the basis of a center frequency and a bandwidth used by the target wireless communication system from an input terminal 11. An interference detection circuit 3 obtains a level of a signal from the band selection circuit 2 and provides an output of it as an interference level signal. An interference judgement circuit 4 compares the interference level signal with an interference level giving effect on the wireless communication system being the target on the basis of an identifier from the input terminal 11 and informs an operator about occurrence of interference through an interference notice circuit 5 when the interference level signal is greater than the interference level. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an alarm device, an alarm generation method used therefor, and a program therefor, and more particularly to an alarm device that promptly notifies a user of deterioration caused by interference in a wireless communication system.

  In recent years, Internet access has become commonplace, and use of the Internet from ordinary households has become widespread. For example, when accessing the Internet via a telephone line, it is necessary to perform cabling from the telephone port in the home to the information device, which causes inconvenience and aesthetic inconvenience. For this reason, a technology for wirelessly connecting a home information device and a communication interface for Internet access such as a telephone port is known.

  Examples of such a wireless communication system include a wireless LAN (Local Area Network) compliant with the IEEE 802.11b standard shown in Non-Patent Document 1 and Bluetooth (registered trademark) (hereinafter referred to as Bluetooth) shown in Non-Patent Document 2. And a wireless system called ”is known. These systems are communication systems that use frequencies in the 2.4 GHz band, as described on page 11 of Non-Patent Document 1 and page 19 of Non-Patent Document 2.

When performing wireless communication, interference from not only other transmission devices belonging to the same system and transmission devices of other systems but also devices that generate radio waves in the same frequency band affects communication quality. For example, Patent Document 1 discloses an apparatus that continues wireless relay while avoiding the influence of interference waves. Patent Document 2 discloses a method of automatically changing a channel such as a frequency at which communication is performed when interference with the own system is detected.
Japanese Patent Laid-Open No. 07-143090 JP 2000-022712 A IEEE Std 802.11b-1999, Supplement to IEEE Standard for Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications : Higher-Speed Physical Layer (PHY) Extension in the 2.4 GHz Band BLUETOOTH (registered trademark) SPECIFICATION Version 1.0B

  However, the above-described conventional technique reduces the influence of interference on an operating wireless communication system. In general homes and the like, it is efficient to know in advance whether interference has occurred and to install a system that does not cause interference. In addition, in a wireless communication system in which the interference avoidance technique shown in the conventional technique is not implemented, it is difficult to find a method for dealing with performance degradation due to interference, and the expected communication performance cannot be enjoyed. There is.

  As a technique for detecting and informing such user inconvenience in advance, for example, there is a fire detection device disclosed in Japanese Patent Laid-Open No. 62-276420, which is used for detecting interference with a wireless communication system. I can't.

  Japanese Patent Application Laid-Open No. 5-136747 discloses a technique for preventing damage to the transmitter and the antenna by connecting a directional coupler to the antenna of the transmitter and detecting an unexpected reflected wave. It has been suggested that this technique can also be used for interference detection. However, the technology described in the above publication is combined with a wireless transmitter, and it is impossible to anticipate possible interference before obtaining the wireless device.

  Accordingly, an object of the present invention is to provide an alarm device that can solve the above problems, can easily detect interference that may occur in a wireless communication system, and can provide a guideline for eliminating communication quality degradation due to interference. Another object of the present invention is to provide an alarm generation method used therefor and a program therefor.

  The alarm device according to the present invention is configured to detect whether or not there is an interference source that causes interference to the system based on a communication system identification signal that is input from the outside and identifies a system that performs communication. Notification means for notifying the occurrence of communication quality degradation due to the interference as an alarm when the detection means detects the presence of the interference source.

  Another alarm device according to the present invention receives a radio wave via an antenna and inputs a communication system identification signal for identifying a system that performs communication, and interferes with the system that performs the communication based on the communication system identification signal. A signal extracting unit that extracts a possible component as an interference component, and an interference that outputs an interference occurrence detection signal that indicates whether the interference component can deteriorate characteristics of the system that inputs the interference component and performs communication For a user of the system that performs the communication when the interference occurrence detection signal is input and the interference occurrence detection signal indicates that the interference component can degrade the characteristics of the system that performs the communication. Means for notifying that interference has occurred.

  Another alarm device according to the present invention receives a radio wave via an antenna and inputs a communication system identification signal for identifying a system that performs communication, and provides interference to the system that performs the communication based on the communication system identification signal. A signal extracting unit that extracts a possible component as an interference component, and an interference that outputs an interference occurrence detection signal that indicates whether the interference component can deteriorate characteristics of the system that inputs the interference component and performs communication When the interference component and the interference occurrence detection signal are input to the detection means and the interference occurrence detection signal indicates that the interference component can degrade the characteristics of the system performing the communication, the interference component A means for estimating a cause and outputting an interference component cause identification signal; and inputting the interference occurrence detection signal and the interference component cause identification signal and performing the communication Interfere with the stem of the user and a means for notifying a reason for generating the a Oyobi the interference has occurred.

  The alarm generation method according to the present invention detects whether or not there is an interference source that causes interference to the system based on a communication system identification signal that is input from the outside and identifies a system that performs communication. And a step of notifying the occurrence of communication quality degradation due to the interference as an alarm when the presence of the interference source is detected.

  In addition to the above steps, another alarm generation method according to the present invention includes a step of estimating the type of the interference source, and notifies the type of the interference source together with the alarm.

  The program of the alarm generation method according to the present invention determines whether or not there is an interference source that causes interference to the system based on a communication system identification signal that identifies the system that is input from the outside and that performs communication. A process of detecting and a process of notifying the occurrence of communication quality degradation due to the interference as an alarm when the presence of the interference source is detected are executed.

  That is, the alarm device of the present invention inputs specifications such as a band and a center frequency of a wireless communication system used by a user, detects interference generated in the system, and causes interference when interference occurs. It has means for notifying an alarm that it has occurred. In addition, the alarm device of the present invention includes means for notifying the user of the cause causing the detected interference as well as the above alarm.

  The 2.4 GHz band used as an ISM (Industry, Science and Medical) band is, for example, not only a wireless LAN called IEEE 802.11b standard, a wireless system called Bluetooth, but also a microwave oven used in general homes. Yes. For this reason, it is expected that the influence of radio wave interference will appear greatly in the future. Such radio wave interference can be estimated by radio communication experts, but it is considered extremely difficult for general users.

  As to whether or not interference occurs, the influence on the target communication system can be estimated by measuring the power that can be generated in the frequency band based on the center frequency and band used by the target wireless communication system. It becomes possible. For general users, information on whether or not interference occurs is also important, but if there is information about the cause of the interference, it is possible to take measures against the interference source.

  Signal envelopes radiated from microwave ovens used in general homes are, for example, Ad Kamerman, Nedim Erkocevic, “Microwave Open Interference on Wireless LANs Operating in the 2.4 GHz ISM Band, IEE Bands” (IEEE, Ps. 1997. Waves of the year 2000, PIMRC '97., The 8th IEEE International Symposium on, Volume: 3, 1997), this is a pulse signal of about 20 milliseconds. The envelope of the transmission signal of IEEE 802.11b varies depending on the data length to be transmitted, but when 1500 bytes of data is transmitted, it becomes a pulse of about 1 millisecond. Further, since the Bluetooth transmission signal is one, three, or five times as long as 625 microseconds, the envelope is a pulse of any one of these lengths.

  The spectrum of IEEE802.11b is a 20 MHz band per channel, Bluetooth is a 1 MHz band per channel, and a home microwave oven has a bandwidth of about 15 MHz.

  As described above, the interference source can be estimated by analyzing the pulse length on the time axis and the spectrum on the frequency axis with respect to the frequency band used by the target communication system. For example, if it is estimated that the interference source is a microwave oven, even a user in a general household can take measures such as refraining from using the microwave oven during communication. That is, it is possible to easily detect interference that may occur in the wireless communication system, and to provide a guideline for eliminating communication quality degradation due to interference.

  According to the present invention, the presence of an interference source is detected based on a communication system identification signal that is input from the outside and identifies a system that performs communication. By detecting the occurrence of communication quality degradation due to the interference as an alarm when it is detected, it is possible to easily detect interference that may occur in the wireless communication system, and to provide guidelines for eliminating communication quality degradation due to interference. There is an effect that can be given.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an alarm device according to an embodiment of the present invention. In FIG. 1, an alarm device 1 includes a band selection circuit 2, an interference detection circuit 3, an interference determination circuit 4, an interference notification circuit 5, a baseband transmission / reception circuit 6, a high frequency transmission circuit 7, a recording medium 8, The receiving antenna 10, the input terminal 11, the transmitting antenna 12, and the input / output terminal 13 are configured.

  FIG. 2 is a flowchart showing the processing operation of the alarm device 1 according to one embodiment of the present invention. The processing operation of the alarm device 1 according to one embodiment of the present invention will be described with reference to FIG. 1 and FIG. The processing operation shown in FIG. 2 is realized by executing a program stored in the recording medium 8 by a computer (not shown) of the alarm device 1.

  An identifier for identifying the target wireless communication system is input from the input terminal 11 (step S1 in FIG. 2). The identifier includes at least 1) a center frequency used by the target wireless communication system, 2) a bandwidth used by the target wireless communication system, and 3) an interference wave level that affects the target wireless communication system. It is included. It is also possible to input only an identifier that allows the alarm device to identify the wireless communication system and convert it into the above three values within the alarm device.

  The radio wave received by the receiving antenna 10 is input to the band selection circuit 2. The band selection circuit 2 selects a signal including a band used by the target wireless communication system based on the center frequency and bandwidth used by the target wireless communication system from the identifiers input from the input terminal 11. (FIG. 2, step S2).

  The signal selected by the band selection circuit 2 is input to the interference detection circuit 3. The interference detection circuit 3 obtains the level of the input signal and outputs it as an interference level signal to the interference determination circuit 4 (step S3 in FIG. 2).

  The interference determination circuit 4 compares the interference level signal from the interference detection circuit 3 and the identifier input from the input terminal 11 with the interference wave level that affects the target wireless communication system (step S4 in FIG. 2).

  When the interference level signal from the interference detection circuit 3 is larger than the interference wave level that affects the wireless communication system (step S5 in FIG. 2), the interference determination circuit 4 determines that interference exists, and the interference notification circuit 5 has interference. An interference detection signal indicating the occurrence is output.

  When an interference detection signal is input from the interference determination circuit 4, the interference notification circuit 5 notifies the user using means such as sound, light, vibration, etc. to indicate that interference has occurred to the user ( FIG. 2 step S6).

  In addition, the alarm device according to one embodiment of the present invention uses a transmission antenna 12, a high-frequency transmission circuit 7, a baseband transmission / reception circuit 6, and an input / output terminal 13, thereby enabling transmission / reception of a target wireless communication system. It can also be integrated.

  The signal reception operation is completed by demodulating the selected signal by the baseband transmission / reception circuit 6 and outputting it to the input / output terminal 13 because the signal selected by the band selection circuit 2 includes the band of the target radio vision system. To do. The signal transmission operation is completed by modulating the transmission signal input from the input / output terminal 13 by the baseband transmission / reception circuit 6 and transmitting it via the high-frequency transmission circuit 7 and the transmission antenna 12.

  FIG. 3 is a block diagram showing a configuration of the band selection circuit 2 of FIG. In FIG. 3, the band selection circuit 2 includes an input terminal 20, an oscillator 21, a down converter 22, a band pass filter 23, and an output terminal 24.

  Based on the identifier of the target wireless communication system input from the input terminal 11, the oscillator 21 and the bandpass filter 23 can select a signal of the wireless communication system identified by the identifier of the target wireless communication system. As described above, the oscillation frequency and the pass band are respectively determined.

  The input terminal 20 inputs a high-frequency signal received by the receiving antenna 10, is converted into an intermediate frequency signal suitable for the target wireless communication system by the down converter 22, and is used by the target wireless communication system by the bandpass filter 23. The band is limited to the band including the band, unnecessary noise and interference components are removed, and output to the output terminal 24.

  FIG. 4 is a block diagram showing the configuration of the interference detection circuit 3 and the interference determination circuit 4 of FIG. In FIG. 4, the interference detection circuit 3 includes an input terminal 30, an envelope detection circuit 31, and an AD (analog / digital) converter 32. The interference determination circuit 4 includes an input terminal 40, a threshold memory 41, The comparison circuit 42 and an output terminal 43 are included.

  The envelope detection circuit 31 receives the signal output from the output terminal 24 of the band selection circuit 2 and detects its envelope. As the envelope detection circuit 31, for example, a log amplifier can be used. The envelope detected by the envelope detection circuit 31 is converted into a digital value by the AD converter 32.

  On the other hand, an identifier of the target wireless communication system is input to the input terminal 40 of the interference determination circuit 4, and an interference wave level that affects the target wireless communication system is stored in the threshold memory 41.

  The comparison circuit 42 compares the output of the AD converter 32 with the value stored in the threshold value memory 41, and if interference occurs when the output of the AD converter 32 is larger than the value stored in the threshold value memory 41. The interference detection signal is output via the output terminal 43.

  FIG. 5 is a block diagram showing a configuration of an alarm device according to another embodiment of the present invention. In FIG. 5, the alarm device 100 includes a receiving antenna 110, an input terminal 111, a band selection circuit 200, an interference analysis circuit 300, an interference detection circuit 400, an interference determination circuit 500, an interference notification circuit 600, and a recording medium. 700.

  The alarm device 100 according to another embodiment of the present invention shown in FIG. 1 indicates that the alarm device 100 according to another embodiment of the present invention notifies not only the presence / absence of interference but also the interference source to the user by the interference notification circuit 600. This is a different point from 1.

  Here, in the alarm device 100 according to another embodiment of the present invention, the reception antenna 110, the input terminal 111, the band selection circuit 200, the interference detection circuit 400, the reception antenna 10, the input terminal 11, and the band selection circuit 2 of FIG. The same one as the interference detection circuit 3 can be used.

  Further, the alarm device 100 according to another embodiment of the present invention uses the transmission antenna 12, the high-frequency transmission circuit 7, the baseband transmission / reception circuit 6, and the input / output terminal 13 as in the alarm device according to an embodiment of the present invention. Thus, it can be integrated with a transceiver of a target wireless communication system.

  FIG. 6 is a flowchart showing the processing operation of the alarm device 100 according to another embodiment of the present invention. The processing operation of the alarm device 100 according to another embodiment of the present invention will be described with reference to FIGS. In FIG. 6, steps S11 to S13 are the same as steps S1 to S3 according to the embodiment of the present invention shown in FIG. Further, the processing operation shown in FIG. 6 is realized by executing a program stored in the recording medium 700 by a computer (not shown) of the alarm device 100.

  The interference analysis circuit 300 includes an interference level that can affect the target wireless communication system included in the identifier of the target wireless communication system from the input terminal 111, and an interference level signal supplied from the interference detection circuit 400. Then, the interference signal is analyzed using the interference signal of the signal supplied from the band selection circuit 200, the source causing the interference is estimated (step S14 in FIG. 6), and the estimation result is output to the interference determination circuit 500.

  On the other hand, the interference determination circuit 500 receives the interference level signal from the interference detection circuit 400 and the identifier of the target wireless communication system from the input terminal 111. The interference determination circuit 500 uses the interference level that can affect the target wireless communication system included in the identifier of the target wireless communication system and the presence or absence of interference using the interference level signal from the interference detection circuit 400. (Steps S15 and S16 in FIG. 6), and the interference source is output to the interference notification circuit 600 based on the estimation result of the interference source supplied from the interference analysis circuit 300.

  When interference occurs in the interference notification circuit 600, not only the occurrence of the interference but also the user is notified of the interference source using means such as sound, light, vibration (step S17 in FIG. 6).

  FIG. 7 is a block diagram showing a configuration of the interference analysis circuit 300 of FIG. In FIG. 7, the interference analysis circuit 300 includes input terminals 311 to 313, a time domain analysis circuit 320, a frequency domain analysis circuit 330, an interference analysis circuit 340, and an output terminal 314.

  A signal output from the band selection circuit 200 is input to the input terminal 311 and input to the time domain analysis circuit 320 and the frequency domain analysis circuit 330. An interference level signal output from the interference detection circuit 400 is input from the input terminal 312. An identifier of the target wireless communication system is input to the input terminal 313.

  Based on these input signals, the time domain analysis circuit 320 and the frequency domain analysis circuit 330 analyze the duration and frequency spectrum of the interference signal, respectively, and the results are used as the time domain analysis result and the frequency domain analysis result. Output to. The interference analysis circuit 500 estimates the interference source based on the time domain analysis result and the frequency domain analysis result, and outputs the estimation result to the output terminal 314.

  FIG. 8 is a block diagram showing a configuration of the time axis analysis circuit 320 of FIG. In FIG. 8, the time axis analysis circuit 320 includes a comparison circuit 321, a threshold memory 322, an addition circuit 323, a max hold (maximum value hold) circuit 324, a memory 325, a timer 326, an input terminal 327, 328 and an output terminal 329.

  An interference level signal output from the interference detection circuit 400 is input to the input terminal 327 via the input terminal 311. On the other hand, an identifier of the target wireless communication system is input to the input terminal 328, and a threshold value based on an interference level that affects the target wireless communication system is stored in the threshold value memory 322.

  The comparison circuit 321 sequentially compares the value stored in the threshold value memory 322 with the interference level signal input from the input terminal 327, and when the interference level signal is larger than the threshold value, “1” is small. "0" is output to each.

  The memory 325 holds the result of adding the currently held value and the output of the comparison circuit 321 by the addition circuit 323. When “0” is output from the comparison circuit 321 to the memory 325, the held value is reset. In this way, the output from the adder circuit 323 indicates the number of “1” s that are continuously output from the comparator circuit 321.

  The output of the adder circuit 321 is output to the max hold circuit 324, and the maximum value is held in the max hold circuit 324. The timer 326 is a timer that counts the analysis time. When the timer 326 times out, the held value is output to the output terminal 329 as the time domain analysis result.

  The time domain analysis result indicates the maximum time during which the interference level exceeds the threshold value stored in the threshold value memory 322 within the observation time defined by the timer 326, and represents the duration time of the interference signal.

  FIG. 9 is a block diagram showing a configuration of the frequency domain analysis circuit 330 of FIG. In FIG. 9, the frequency domain analysis circuit 330 includes input terminals 3300 to 3302, a variable gain amplifier 3303, an orthogonal demodulation circuit 3304, a gain control circuit 3305, a low-pass filter 3306, and an AD (analog / digital) conversion circuit 3307. A serial / parallel conversion circuit 3308, a fast Fourier transform (FFT) circuit 3309, power detection circuits 3310-1 to 3310-n, comparison circuits 3311-1 to 3311-n, and a threshold memory 3312. / Serial conversion circuit 3313, counter 3314, max hold (maximum value hold) circuit 3315, timer 3316, and output terminal 3317.

  The identifier of the target wireless communication system is input to the input terminal 3301, and a level based on the interference level that affects the target wireless communication system is stored in the threshold memory 3312.

  A signal supplied from the band selection circuit 200 is input to the input terminal 3302. The gain of this signal is adjusted so as to be an appropriate level based on the interference level signal output from the interference detection circuit 400 input via the input terminal 3300. This gain adjustment is performed by a gain control circuit 3305 and a variable gain amplifier 3303.

  The signal whose gain has been adjusted by the variable gain amplifier 3303 is quadrature demodulated by the quadrature demodulation circuit 3304. The quadrature demodulation circuit 3304 includes an in-phase component and a quadrature component, but here, in order to simplify the drawing, a diagonal line is written in a signal line at a portion where the in-phase component and the quadrature component flow.

  The quadrature demodulated signal has its frequency component removed by a low-pass filter 3306 and then converted to a digital signal by an AD conversion circuit 3307. The signals converted into digital signals are rearranged in parallel by n serial signals in time by a serial / parallel conversion circuit 3308 and input to the fast Fourier transform circuit 3309. Here, it is assumed that the fast Fourier transform circuit 3309 performs n-point fast Fourier computation.

  The signal subjected to the Fourier transform by the fast Fourier transform circuit 3309 outputs n frequency components included in the n signals in time series, and each power is detected by the power detection circuits 3310-1 to 3310-n. . The power detected by the power detection circuits 3310-1 to 3310-n is input to the comparison circuits 3311-1 to 33111-n and compared with the threshold value stored in the memory 3312.

  In the comparison circuits 3311-1 to 3131-n, “1” is set when the value output from the power detection circuits 3310-1 to 3310-n is larger than the threshold value stored in the memory 3312, and “ 0 "is output respectively. “1” or “0” output from the comparison circuits 3311-1 to 33111 -n is input to the parallel / serial conversion circuit 3313, and is output in series in the order of, for example, low frequency components to high frequency components.

  Also, when the parallel / serial conversion circuit 3313 outputs n values in series, a reset signal is sent to the counter 3314 in advance. The counter 3314 counts up and outputs the number of “1” s output from the parallel / serial conversion circuit 3313, and resets when “0” is input. In this way, the Mac hold circuit 3315 holds a value indicating a continuous band having a component exceeding the threshold value stored in the threshold value memory 3312. This value is equal to a value indicating the maximum frequency band of the interference component.

  The timer 3316 is a timer that defines the observation time. When the timer 3316 times out, the max hold circuit 3315 outputs the held value to the output terminal 3317 as the frequency domain analysis result.

  FIG. 10 is a block diagram showing a configuration of the interference analysis circuit 500 of FIG. In FIG. 10, the interference analysis circuit 500 includes input terminals 341 and 342, an interference pattern storage circuit 343, and an output terminal 344.

  The input terminals 341 and 342 receive time domain analysis results and frequency domain analysis results, respectively. An interference source is output by supplying signals from the input terminals 341 and 342 as addresses to an interference pattern storage circuit 343 that stores an interference source that generates an interference pattern determined by a time domain analysis result or a frequency domain analysis result. Output to the terminal 344.

  FIG. 11 is a diagram showing an example of contents stored in the interference pattern storage circuit 343 of FIG. In FIG. 11, the interference pattern storage circuit 343 stores an interference source to be estimated in a region where a column determined by the time domain analysis result and a row determined by the frequency domain analysis result intersect, and is input from input terminals 341 and 342. The stored interference source is output based on the measured value. As the interference source, for example, a wireless LAN compliant with the IEEE 802.11b standard, a wireless system compliant with the Bluetooth standard, or a typical home microwave oven is output.

  FIG. 12 is a block diagram showing a configuration of the interference determination circuit 500 of FIG. In FIG. 12, the interference determination circuit 500 includes input terminals 501 to 503, a threshold memory 504, a comparison circuit 505, a multiplexing circuit 506, and an output terminal 507.

  The input terminal 501 receives an identifier of the target wireless communication system input from the input terminal 111, and determines whether or not interference occurs based on an interference level that can affect the target wireless communication system. The threshold value is stored in the threshold memory 504.

  An interference level signal output from the interference detection circuit 400 is input to the input terminal 502. The comparison circuit 505 compares the interference level signal with the threshold value stored in the threshold memory 504, determines that interference has occurred when the interference level signal is greater than the threshold value, and sets "1". If it is small, it is determined that no interference has occurred, and “0” is generated.

  Further, the interference terminal estimation result output from the interference analysis circuit 300 is input to the input terminal 503. The multiplexing circuit 506 multiplexes the output of the comparison circuit 505 indicating the presence or absence of interference and the interference source estimation result input from the input terminal 503, and outputs the result to the interference notification circuit 600 via the output terminal 507.

  FIG. 13 is a diagram schematically showing temporal changes in the envelope of a transmission waveform transmitted by a wireless LAN or Bluetooth of the IEEE 802.11b standard and the envelope of a signal radiated from a microwave oven. In FIG. 13, A is a signal radiated from a microwave oven, B is a Bluetooth transmission signal, and C is an envelope corresponding to an IEEE 802.11b transmission signal.

  Signal envelopes radiated from microwave ovens used in general homes are, for example, Ad Kamerman, Nedim Erkocevic, “Microwave Open Interference on Wireless LANs Operating in the 2.4 GHz ISM Band,” IEEE, P Waves of the year 2000, PIMRC '97., The 8th IEEE International Symposium on, Volume: 3, 1997), this is a pulse signal of about 20 milliseconds.

  The envelope of the transmission signal of IEEE 802.11b differs depending on the data length to be transmitted, but when transmitting 1500 bytes of data, it becomes a pulse of about 1 millisecond. Furthermore, since the Bluetooth transmission signal is one, three, or five times as long as 625 microseconds, its envelope is a pulse of any one of these lengths.

  FIG. 14 is a diagram schematically showing a transmission spectrum of IEEE 802.11b or Bluetooth and a spectrum emitted from a microwave oven. In FIG. 14, D-1 to D-3 are spectra showing three channels out of 14 channels defined by IEEE 802.11b, F-1 and F-2 are Bluetooth spectra, and E is from a microwave oven. An example of the emitted spectrum is shown.

  The spectrum of IEEE802.11b is a 20 MHz band per channel, Bluetooth is a 1 MHz band per channel, and a home microwave oven has a bandwidth of about 15 MHz.

  As described above, the interference source can be estimated by analyzing the pulse length on the time axis and the spectrum on the frequency axis with respect to the frequency band used by the target communication system. For example, if it is estimated that the interference source is a microwave oven, even a general household user can take measures such as refraining from using the microwave oven during communication.

  Therefore, it is possible to easily detect interference that may occur in the wireless communication system, and to provide a guideline for eliminating communication quality deterioration due to interference.

It is a block diagram which shows the structure of the alarm generator by one Example of this invention. It is a flowchart which shows operation | movement of the alarm generator by one Example of this invention. FIG. 2 is a block diagram illustrating a configuration of a band selection circuit in FIG. 1. It is a block diagram which shows the structure of the interference detection circuit and interference determination circuit of FIG. It is a block diagram which shows the structure of the alarm generator by the other Example of this invention. It is a flowchart which shows operation | movement of the alarm generator by other Examples of this invention. FIG. 6 is a block diagram illustrating a configuration of the interference analysis circuit of FIG. 5. It is a block diagram which shows the structure of the time-axis analysis circuit of FIG. It is a block diagram which shows the structure of the frequency domain analysis circuit of FIG. FIG. 6 is a block diagram showing a configuration of the interference analysis circuit of FIG. 5. It is a figure which shows an example of the content memorize | stored in the interference pattern memory | storage circuit of FIG. FIG. 6 is a block diagram illustrating a configuration of an interference determination circuit in FIG. 5. It is a figure which shows typically the time change of the envelope of the transmission waveform transmitted by the wireless LAN of IEEE 802.11b specification, or Bluetooth, and the envelope of the signal radiated | emitted from a microwave oven. It is a figure which shows typically the spectrum radiated | emitted from the transmission spectrum and microwave oven of IEEE802.11b or Bluetooth.

Explanation of symbols

1,100 alarm device
2,200 Band selection circuit
3,400 Interference detection circuit
4,500 interference judgment circuit
5,600 Interference notification circuit
6 Baseband transceiver circuit
7 High-frequency transmission circuit
8,700 Recording medium
10, 110 receiving antenna 11, 20, 30, 40, 111,
311 to 313, 327, 328,
3300-3302, 341
342, 501-503 input terminals
12 Transmitting antenna
13 Input / output terminals
21 Oscillator
22 Downconverter
23 band pass filters 24, 42, 314, 329,
3317,344,507 Output terminal
31 Envelope detection circuit
32 AD converter 41,322,504,3312 Threshold memory
42 Comparison circuit
300 Interference analysis circuit
320 Time domain analysis circuit 321, 505
3311-1-3311-n comparison circuit
323 Adder circuit
324, 3315 Max hold circuit
325 memory
326, 3316 timer
330 Frequency domain analysis circuit
340 Interference analysis circuit
343 Interference pattern storage circuit
506 Multiplexing circuit
3303 Variable Gain Amplifier
3304 Quadrature demodulation circuit
3305 Gain control circuit
3306 Low pass filter
3307 AD conversion circuit
3308 Series / parallel conversion circuit
3309 fast Fourier transform circuit 3310-1 to 3310-n power detection circuit
3313 Parallel / serial converter circuit
3314 counter

Claims (11)

  Detection means for detecting whether or not there is an interference source that causes interference to the system based on a communication system identification signal that identifies a system that performs communication and that is input from the outside, and the interference source by the detection means And a notification means for notifying the occurrence of communication quality degradation due to the interference as an alarm when the presence of the alarm is detected.   The alarm device according to claim 1, further comprising an estimation unit that estimates a type of the interference source, and notifying the type of the interference source estimated by the estimation unit together with the alarm.   The communication system identification signal includes a carrier frequency for communication, a bandwidth used for communication, and a threshold value for an interference amount for determining whether or not good communication can be performed. The alarm device according to claim 2.   A signal that receives a radio wave via an antenna and receives a communication system identification signal that identifies a system that performs communication, and extracts a component that can interfere with the system that performs communication based on the communication system identification signal as an interference component Extraction means; interference detection means for inputting the interference component and outputting an interference occurrence detection signal indicating whether or not the interference component can degrade characteristics of the communication system; and the interference occurrence detection signal When the interference occurrence detection signal indicates that the interference component can degrade the characteristics of the system that performs the communication, the user of the system that performs the communication is notified that interference has occurred. And an alarm device.   A signal that receives a radio wave via an antenna and receives a communication system identification signal that identifies a system that performs communication, and extracts a component that can interfere with the system that performs communication based on the communication system identification signal as an interference component An extraction means; an interference detection means for inputting an interference component; and outputting an interference occurrence detection signal indicating whether or not the interference component can degrade the characteristics of the communication system; and When an interference occurrence detection signal is input and the interference occurrence detection signal indicates that the interference component can degrade the characteristics of the system that performs the communication, the cause of the interference component is estimated to identify the cause of the interference component A means for outputting a signal, and the interference occurrence detection signal and the interference component cause identification signal are inputted and interferes with a user of the communication system. Alarm device, characterized in that it comprises a means for notifying the cause that the Oyobi generate the interference occurring.   The means for outputting the interference component cause identification signal includes time domain analysis means for analyzing the interference component in the time domain and outputting it as a time domain analysis result, and analyzing the interference component in the frequency domain as a frequency domain analysis result. 6. The alarm device according to claim 5, further comprising: frequency domain analysis means for outputting; and interference analysis means for outputting the interference component cause identification signal based on the time domain analysis result and the frequency domain analysis result.   Detecting whether or not there is an interference source that causes interference with the system based on a communication system identification signal that is input from the outside and identifies a system that performs communication; and the presence of the interference source is detected. And a step of notifying the occurrence of communication quality degradation due to the interference as an alarm.   The alarm generation method according to claim 7, further comprising a step of estimating a type of the interference source, and notifying the type of the interference source together with the alarm.   The communication system identification signal includes a carrier wave frequency for communication, a bandwidth used for communication, and a threshold value for an interference amount for determining whether or not good communication can be performed. The alarm generation method according to claim 8.   A process of detecting whether or not there is an interference source that causes interference to the system based on a communication system identification signal that is input from the outside and identifies the system that performs communication, and the presence of the interference source And a process for notifying the occurrence of communication quality degradation due to the interference as an alarm when a signal is detected.   A process of detecting whether or not there is an interference source that causes interference to the system based on a communication system identification signal that is input from the outside and identifies the system that performs communication, and the presence of the interference source A program for executing the occurrence of communication quality degradation due to the interference when it is detected and the process of notifying the interference source estimated at that time as an alarm.

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