JP2005142750A - Method and system for specifying location - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a system for specifying a location that can more efficiently specify the location of a generation source of noise such as an interfering radio wave. <P>SOLUTION: Each base station 15 measures the intensity of a signal received through a respective antenna and supplies data on the signal intensity to a management system 20. When the signal intensity exceeds a threshold, a management computer 21 of the management system 20 judges whether there is a correlation between signal intensities received by the base station 15 having received the signal intensity exceeding the threshold and by a base station 15 adjacent thereto. When there is no correlation, the management computer 21 estimates that there is an illegal radio wave station 10 nearby the base station 15 having measured the signal intensity exceeding the threshold. When there is a correlation, the management computer 21 estimates that there is an illegal radio wave station 10 between the base stations 15 having the correlation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a position specifying method and a position specifying system for specifying the position of a source of jamming radio waves.

  Today, with the widespread use of mobile phone terminals, it may be desired to use mobile phone terminals even in buildings and underground where radio waves are difficult to reach. For this reason, there is a case where a relay device is provided for relaying radio waves in a building or underground and arriving at a base station on the ground. For example, a technology for providing an indoor service of a mobile phone easily even in a building or underground structure where radio waves transmitted from an antenna of a public base station installed outdoors are difficult to reach (for example, patents) is disclosed. Reference 1). In this technology, a mobile phone is serviced wirelessly through an antenna provided outdoors in a public base station connected to a telephone line. An outdoor relay antenna is provided in the vicinity of the antenna, and an indoor relay antenna is provided in a building or structure where radio waves are difficult to reach. The outdoor relay antenna and the indoor relay antenna are connected by a coaxial cable, and the public base station services the mobile phone in the building or structure.

  Normally, a relay device installed legally is used with a predetermined range of signal power so as not to interfere with other communications. However, a license is required to install the relay device legally. For this reason, an illegal relay device in which power control is not performed may be easily attached.

  By the way, CDMA (Code Division Multiple Access) system is attracting attention as a standard system for mobile phones. This CDMA system is a technique for simultaneously performing a plurality of communications using signals in the same frequency band by a spread spectrum technique. In spread spectrum processing, a digitally-encoded audio signal is subjected to arithmetic processing using a pseudo noise (PN) code on the transmitting side, converted into a signal having a wide frequency spectrum, and transmitted. On the other hand, the receiving side restores the original signal using the same PN code. In such CDMA communication, the base station controls the transmission power of each mobile phone terminal so that the power density of transmission signals arriving from each mobile phone terminal is uniform. This prevents the problem that the signal strength of mobile phone terminals close to the base station becomes too high, and the transmission signals of other distant mobile phone terminals interfere with each other and the signals of some mobile phone terminals cannot be extracted. .

  Even in such a CDMA system, a relay device may be provided at a specific place. However, when an illegal relay device without power control is used, a CDMA base station receiving device is subject to radio wave interference in the vicinity of the relay device due to high-intensity radio waves transmitted by the relay device. . For this reason, the mobile phone terminal cannot communicate with the base station. That is, the radio wave generated by such an illegal relay device becomes a jamming radio wave.

In addition, in order to detect illegal jamming radio waves, the Ministry of Internal Affairs and Communications uses the DEUTect Unlicensed RAdio Stations system. This Duras system is composed of a center station installed in each regional general communication station and the like, a sensor station installed in each place, and a sensor station installed in an illegal radio station search vehicle if necessary. Then, by remotely operating the sensor station installed in each place and the sensor station mounted on the vehicle from the center station installed in the general communication station etc., the radio wave received by the sensor station is monitored, and the radio wave emission source The position of the illegal radio station is specified by measuring the azimuth of the radio.
JP-A-7-154850 (FIG. 1)

  However, since this Durus system requires the installation of a sensor station that performs remote operation, a large capital investment is required. Therefore, a method of detecting the source of the jamming radio wave based on the location of the call failure reported by the user is also used. That is, this is a method of searching for the vicinity of a place where there is a call failure using a troubled radio wave search device and thereby detecting the source of the jamming radio wave. In this case, the location of the call failure is specified by searching for a wide range using the search device for a long time using the search device.

  However, in the method of detecting jamming radio waves based on the location where a call failure is reported, it is not possible to search for jamming radio waves when no call failure is reported. For this reason, with this detection method, it is not possible to remove the source of the jamming radio wave that causes the call failure before the call failure occurs. In addition, when the jamming wave is generated only for a specific time period, it is difficult to detect the source of the jamming radio wave if the jamming radio wave is not generated at the time when the searching device searches around the jamming radio wave. It was.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a position specifying method and a position specifying system that can more efficiently specify the position of a noise generation source such as jamming radio waves.

  In order to solve the above-described problems, the invention described in claim 1 generates noise using a management computer connected to a plurality of base stations that transmit and receive data to and from a plurality of communication terminals by a spread spectrum communication method. A position specifying method for specifying the position of a source, wherein the management computer records the signal strength received by each base station together with the reception time, and the signal strength received by any base station is a threshold value. Based on the extraction step of extracting the signal strength received by the base station adjacent to the base station at the reception time and the correlation of the signal strength received by these adjacent base stations, the location of the source And an estimation stage for estimating.

  According to a second aspect of the present invention, in the localization method according to the first aspect, in the estimation step, when there is a correlation between signal strengths received by adjacent base stations, signals received by these base stations Based on the above, the gist is to estimate the position of the source existing between the base stations.

  According to a third aspect of the present invention, in the position specifying method according to the first or second aspect, the estimation step is received by the base station when there is no correlation in signal strength received by an adjacent base station. The gist is to estimate the position of the source existing in the vicinity of the base station based on the signal.

  According to a fourth aspect of the present invention, in the position specifying method according to any one of the first to third aspects, the estimation step is based on a correlation between the signal strengths received from adjacent signal strengths. The gist of the present invention is to include a determination step of calculating an index indicating the correlation and determining a correlation with the signal strength received by the adjacent base station based on the index.

  According to a fifth aspect of the present invention, in the location specifying method according to the fourth aspect, the determining step is performed based on a shape of a temporal change in signal strength received by an adjacent base station within a predetermined time. The gist is to determine the relationship.

According to a sixth aspect of the present invention, in the position specifying method according to any one of the first to fifth aspects, the management computer can be connected to a search device for searching for the source via a wireless network. The management computer further includes a transmission step of transmitting data relating to the position of the source estimated in the estimation step to the search device via the wireless network.

  A seventh aspect of the present invention is the location specifying method according to the sixth aspect, wherein the management computer transmits the reception status of noise at a specific base station to the search device in response to a request from the search device. The gist of the present invention is to further include a transmission status transmission step.

  The invention according to claim 8 is a position specifying system for specifying the position of a noise generation source using a management computer connected to a plurality of base stations that transmit and receive data to and from a plurality of communication terminals by a spread spectrum communication system. The management computer records the signal strength received by each base station together with the reception time, and at the reception time when the signal strength received by any base station is equal to or greater than a threshold value. Extraction means for extracting the signal strength received by the base station adjacent to the base station, and estimation means for estimating the position of the source based on the correlation of the signal strength received by these adjacent base stations Is the gist.

  According to a ninth aspect of the present invention, in the location system according to the eighth aspect, when the estimation means has a correlation with the signal strength received by an adjacent base station, the signals received by these base stations Based on the above, the gist is to estimate the position of the source existing between the base stations.

  According to a tenth aspect of the present invention, in the positioning system according to the eighth or ninth aspect, the estimation means is received by the base station when there is no correlation in signal strength received by an adjacent base station. The gist is to estimate the position of the source existing in the vicinity of the base station based on the signal.

  An eleventh aspect of the present invention is the positioning system according to any one of the eighth to tenth aspects, wherein the estimation means calculates a correlation between signal strengths received from adjacent signal strengths. The gist of the present invention is to include a determination unit that calculates an index indicating the correlation between the signal strengths received by adjacent base stations based on the index.

  According to a twelfth aspect of the present invention, in the positioning system according to the eleventh aspect, the determination means performs correlation based on a shape of a temporal change in signal strength received by an adjacent base station within a predetermined time. The gist is to determine the relationship.

  According to a thirteenth aspect of the present invention, in the location system according to any one of the eighth to twelfth aspects, the management computer can be connected to a search device for searching for the source via a wireless network. The management computer further includes transmission means for transmitting data relating to the position of the source estimated by the estimation means to the search device via the wireless network.

  According to a fourteenth aspect of the present invention, in the position specifying system according to the thirteenth aspect, the management computer transmits the reception status of noise at a specific base station to the searching device in response to a request from the searching device. The gist of the present invention is to further include a transmission status transmission means.

(Function)
According to the first or eighth aspect of the present invention, the management computer has a correlation with the signal strength received by the antenna of the base station adjacent to the base station when the signal strength received by the base station is greater than or equal to the threshold value. Based on the above, the position of the source is estimated. Therefore, even if there is no report of communication failure,
The location of the noise source can be estimated using existing equipment. Therefore, it is possible to efficiently identify the noise source.

  According to the invention described in claim 2 or 9, when there is a correlation between the signal strengths received by the adjacent base stations, the management computer can receive both base stations, that is, It is estimated that there is a noise source between the base stations. For this reason, the noise generation source can be identified efficiently.

  According to the third or tenth aspect of the present invention, when there is no correlation between the signal strengths received by the adjacent base stations, the management computer has noise in the vicinity of the base station where the signal strength is equal to or greater than the threshold value. Estimate that there is a source of Therefore, the generation of noise can be identified efficiently.

  According to the invention described in claim 4 or 11, the management computer calculates an index indicating the correlation, and determines that the signal intensity has a correlation when the index is equal to or greater than a predetermined value. For this reason, the management computer can determine whether or not there is a correlation. For example, when a correlation coefficient is used as an index indicating the correlation, the correlation can be determined based on this value.

  According to the fifth or twelfth aspect of the present invention, the management computer determines that the signal strength of the base station is correlated when the waveform of the temporal change in signal strength has the same shape. Since the temporal variation of the signal generated from the generation source is constant, the temporal change in signal strength received by a plurality of base stations is the same for the same generation source. For this reason, if the waveform of the signal intensity is the same, it can be easily determined that there is a correlation, and the generation source can be specified. For example, if the shape of the temporal change in signal strength received by an adjacent base station is approximate and the error is within a predetermined range, it can be determined that there is a correlation.

  According to the invention described in claim 6 or 13, the management computer transmits data relating to the estimated position of the source in the search device. The position of the source estimated from the signal intensity may differ from the actual position of the noise source due to reflection or diffraction of the signal by the building. For this reason, the position of the noise generation source can be more reliably specified by causing the search device to search for the generation source based on the position of the generation source estimated by the management computer.

  According to the seventh or fourteenth aspect of the invention, the management computer transmits the noise reception status to the search device when the signal strength in the specific base station is equal to or greater than the threshold in response to a request from the search device. For this reason, since the search device can search the generation source according to the actual transmission state of noise, the generation source can be identified efficiently.

  According to the present invention, a noise generation source can be identified efficiently.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, a mobile phone terminal 11 as a communication terminal used in the present invention transmits and receives data to and from a base station 15 by a CDMA method. More specifically, the cellular phone terminal 11 performs communication by performing spread conversion on an information signal using a specific encoding code from the base station 15 with which it communicates.

In the present embodiment, a plurality of base stations 15 are installed for ordinary mobile phone calls. In the present embodiment, the base station 15 includes, for example, three directional antennas and corresponds to a so-called three-sector cell system. In this embodiment, the antenna of each base station 15 is configured so that its directivity can be electrically changed. The base station 15 transmits and receives data to and from the mobile phone terminal 11 located in each cell (area) via the antenna.

  Further, each base station 15 includes a known signal strength measuring device that measures the signal strength received via each antenna. In this embodiment, the signal strength measuring apparatus separates the received signal strength for each channel and measures the signal strength for each separated channel. In this embodiment, this channel means a specific frequency band in which signals from a plurality of mobile phone terminals 11 are spread by a spread spectrum technique. In the present embodiment, description will be made using measurement results of five channels (frequency bands).

  The plurality of base stations 15 are connected to the management system 20 via the mobile phone network N. The management system 20 includes a management computer 21. The management computer 21 includes a CPU, a RAM, a ROM, and the like (not shown), and performs processing described later (an estimation step including a recording step, an extraction step, a determination step, a transmission step, and a transmission status transmission step). Therefore, the management computer 21 functions as an estimation unit including a recording unit, an extraction unit, and a determination unit, a transmission unit, and a transmission status transmission unit.

The management computer 21 is connected to the signal strength data storage unit 22 and the map data storage unit 23.
In the signal strength data storage unit 22, signal strength measurement data of each base station 15 received via each antenna is recorded together with the reception time. This measurement data is recorded together with information on the separated channels. For this reason, the management computer 21 can obtain the temporal change for each channel of the signal strength received by one antenna of a certain base station 15 from the signal strength data recorded in the signal strength data storage unit 22.

  The map data storage unit 23 stores nationwide map data, position data of each base station 15, and data related to a cell managed by the antenna of each base station 15. Therefore, the management computer 21 can estimate the calculated position of the noise source on the map based on the data in the map data storage unit 23.

Further, the management computer 21 includes an antenna 26 and transmits data to the search vehicle 30 via the antenna 26.
The search vehicle 30 is a vehicle that searches while moving the location of the noise source. The search vehicle 30 is provided with a GPS device 31 and a receiving antenna 32. The GPS device 31 is a device for receiving a known GPS signal and acquiring the current position of the search vehicle 30. The receiving antenna 32 is an antenna for receiving radio waves transmitted from the illegal radio station 10.

  Further, the search vehicle 30 is equipped with a computer 35. The GPS device 31 is connected to the computer 35, and data on the current position of the search vehicle 30 is acquired. Further, the computer 35 receives radio waves emitted from the illegal radio station 10 via the reception antenna 32. Further, the computer 35 receives data regarding the position of the noise source from the management computer 21 via the antenna 36. In addition, the computer 35 can request the management computer 21 for the current status of the signal strength received by the predetermined base station 15.

Next, processing of the management system 20 for specifying the position of the illegal radio station 10 when the illegal radio station 10 generates a large signal (noise) will be described.
For communication with the base station 15, the mobile phone terminal 11 transmits a radio wave obtained by spreading and converting the information signal using the encoded code assigned from the base station 15. Each antenna of each base station 15 receives a radio wave transmitted from the mobile phone terminal 11 in the cell in charge. At this time, for example, radio waves transmitted from the mobile phone terminals 11 located in the overlapping cells are received by the antennas of the plurality of base stations 15 that have jurisdiction over them. Then, the base station 15 performs transmission power control on each mobile phone terminal 11 so that the signal strength received from the mobile phone terminal 11 is uniform. In the present embodiment, the base station 15 controls the signal strength received from each mobile phone terminal 11 to be 4 [dB] or less in all channels.

  The base station 15 receives a multiplexed signal from the mobile phone terminal 11 in each cell via each antenna. The base station 15 despreads the received multiplexed signal using an encoding code assigned to each mobile phone terminal 11 and extracts an information signal from each mobile phone terminal 11. In the CDMA system, soft handover is adopted. Therefore, before and after the soft handover, a plurality of base stations 15 simultaneously receive signals from the respective mobile phone terminals 11, and these signals are supplied to a radio network control device (not shown). Then, the wireless network control device extracts an information signal using signals simultaneously received from the mobile phone terminal 11.

  On the other hand, the signal strength measurement device of the base station 15 measures the signal strength of the signal received via each antenna. The base station 15 supplies the received signal strength together with the reception time to the management system 20 via the mobile phone network N.

  When the management computer 21 of the management system 20 acquires the signal strength measurement data in this manner, the signal strength data storage unit stores the acquired signal strength measurement data for each antenna of each base station 15 and for each channel. Record in 22.

  Then, the management computer 21 periodically executes the estimation process shown in FIG. First, the management computer 21 determines whether or not there is a base station 15 whose acquired signal strength is equal to or greater than a threshold (step S1-1). In the present embodiment, 4 [dB] is set as the threshold value. As this threshold value, a value that becomes an obstacle to the signal strength that each base station 15 normally receives by transmission power control is used. Note that if the management computer 21 determines that there is no base station 15 whose acquired signal strength is greater than or equal to the threshold (in the case of “NO” in step S1-1), the management computer 21 ends this processing.

  Here, if the management computer 21 determines that there is a base station whose signal strength is equal to or greater than the threshold (in the case of “YES” in step S1-1), the correlation is detected in the waveform of the base station 15 adjacent to the detected base station 15. It is determined whether or not there is (step S1-2). Specifically, the management computer 21 observes the signal strength of the base station 15 continuously for a predetermined time. Then, the management computer 21 observes the waveform of the signal strength of the base station 15 and the waveform of the signal strength received at the base station 15 adjacent to the base station 15 within a predetermined range error, which is an approximate shape. Determine whether or not. That is, in this embodiment, a signal intensity waveform is used as an index indicating the correlation.

  When the management computer 21 determines that there is no correlation with the waveform of the adjacent base station 15 (in the case of “NO” in step S1-2), the management computer 21 is located near the base station 15 that has received a signal strength equal to or greater than the threshold value. It is estimated that there is an illegal radio station 10 that is a noise source (step S1-3).

  When the management computer 21 determines that there is a correlation with the waveform of the adjacent base station 15 (“YES” in step S1-2), the illegal radio station 10 is located between the adjacent base stations 15. It is estimated that there is (step S1-4).

Here, a method for estimating the position of the illegal radio station 10 will be specifically described with reference to FIGS. As shown in FIG. 3, base stations 15 are provided at points A to C on the map. The base stations 15 at the points A to C are provided with antennas a to c, respectively.

  FIG. 4 is a diagram showing the change over time of the signal strength received by the antenna a of the base station 15 at the point A in FIG. FIG. 5 is a diagram showing a time change of the signal strength received by the antenna b of the base station 15 at the point B in FIG. Further, FIG. 6 is a diagram showing a time change of the signal strength received by the antenna c of the base station 15 at the point C in FIG. Here, the base station 15 at the point A is a base station 15 at the point B and the base station 15 at the point C is adjacent to each other. The antennas a, b, and c receive signals from mobile phone terminals and the like that exist in the cells surrounded by the base stations 15 at the points A, B, and C, respectively. Further, in FIGS. 4 to 6, the received signal strength is displayed for each channel, and five channels are displayed.

  First, at time t1, when the signal strength at the base station 15 at the point A exceeds the threshold value 4 [dB] (in the case of “YES” in step S1-1), the management computer 21 determines that the base station 15 at the point A It is determined whether there is a correlation with the waveform received by the antennas of the base stations 15 at the adjacent points B and C (step S1-2). Specifically, the management computer 21 observes the signal strength of the channel exceeding the threshold value of the base station 15 at the point A until time t2 after a predetermined time (for example, 24 hours). Furthermore, the management computer 21 observes the signal strength of the same channel as the channel exceeding the threshold at the point A, at the base stations 15 at the points B and C adjacent to the point A until time t2.

  At this time, since the waveforms at time t1 to time t2 displayed in FIGS. 5 and 6 are not in the same shape as the correlation with the waveform in FIG. 4, the management computer 21 determines that there is no correlation (step) “NO” in S1-2). Therefore, the management computer 21 estimates that the position of the illegal radio station 10 that is the source of the noise is in the vicinity of the base station 15 at the point A (step S1-3). Furthermore, the management computer 21 calculates the position of the illegal radio station 10 in more detail based on a known method that takes into account the signal strength of noise and signal attenuation due to obstacles on the propagation path. Specifically, the management computer 21 estimates the position of the illegal radio station 10 from the signal intensity received by the antenna a at the point A. Thereby, for example, the management computer 21 estimates that the position of the illegal radio station 10 is the position indicated by “Δ” in FIG. 3. Note that the variation in “Δ” is due to fluctuations in signal propagation.

  Thereafter, when the signal strength at the base station 15 at the point A exceeds 4 [dB] again at the time t3, the management computer 21 similarly receives the signals received by the antennas of the base stations 15 at the adjacent points B and C. It is determined whether there is a correlation with the intensity waveform (step S1-2). Specifically, it is determined whether the waveform of the signal intensity in the same channel at points A, B, and C is approximate.

  Here, in a predetermined time (for example, time t3 to time t4), the waveform shown in FIG. 5 and the waveform shown in FIG. 6 in a specific channel have substantially the same shape as the waveform shown in FIG. Therefore, the management computer 21 determines that there is a correlation with the change waveform of the signal strength received by the antennas of the base stations 15 at the points B and C (“YES” in step S1-2). Then, the management computer 21 estimates that there is an illegal radio station 10 between the base stations 15 at the points A, B, and C (step S1-4). More specifically, the management computer 21 predicts the position of the illegal radio station 10 by a known method from the magnitude of the signal intensity received by each antenna a, b, c. And the management computer 21 estimates that it is a position shown by "x" of FIG. 3, for example. Here, the variation of “x” is due to fluctuations in signal propagation.

Next, the management computer 21 transmits the position data of the noise source estimated in this way to the search vehicle 30 via the antenna 26 (step S1-5).
The computer 35 of the search vehicle 30 that has received the position data of the noise source via the antenna 36 outputs the position information. Based on the position of the estimated noise source (the position indicated by “Δ” or “x”), the search vehicle 30 acquires radio waves with the receiving antenna 32 while circulating around the position. Thereby, the illegal radio station 10 is detected by traveling around the illegal radio station 10 transmitting the illegal radio wave. At this time, the computer 35 requests the management computer 21 for data on whether or not radio waves are transmitted from the illegal radio station 10. In response to this, the management computer 21 provides information regarding radio waves from the illegal radio station 10 to the computer 35. In this way, the computer 35 and the management computer 21 search for the illegal radio station 10 using radio waves received via the base station 15 and the receiving antenna 32 in cooperation with each other.

According to this embodiment, the following effects can be obtained.
In the present embodiment, when the signal strength is greater than or equal to the threshold value (when “YES” in step S1-1), the management computer 21 receives points B and C adjacent to the base station 15 at the point A that received the signal. It is determined whether there is a correlation with the signal strength received by the base station 15 (step S1-2). If there is a correlation (in the case of “YES” in step S1-2), it is estimated that there is an illegal radio station 10 between the base stations 15 determined to have the correlation. When there is no correlation (in the case of “NO” in step S1-2), it is estimated that there is an illegal radio station 10 in the vicinity of the point A of the base station 15 that has received the signal intensity exceeding the threshold. For this reason, the management computer 21 can obtain the position of the illegal radio station 10 that is the source of noise even if there is no report of a faulty call. Further, since the position of the illegal radio station 10 can be estimated by using a signal received by the existing base station 15 of the CDMA system, the location of the illegal radio station 10 can be easily made without making a new capital investment. Can be estimated. Therefore, the position of the illegal radio station 10 can be identified more efficiently.

  In the present embodiment, the management computer 21 determines that the base station 15 at the adjacent points B and C and the waveform due to the temporal change formed by the signal strength received by the base station 15 at the point A from time t3 to time t4. If the received signal intensity has a waveform that is substantially the same due to temporal changes, it is determined that there is a correlation. In this case, the management computer 21 can easily determine that there is a correlation by forming a waveform based on the measurement data of the signal strength and comparing the waveforms. Therefore, the position of the illegal radio station 10 can be easily identified.

  In the present embodiment, the noise source position data estimated by the management computer 21 is supplied to the computer 35 of the search vehicle 30. For this reason, the search vehicle 30 can travel around the estimated noise source and easily search for the illegal radio station 10.

  In the present embodiment, in response to a request from the computer 35, the management computer 21 can transmit information to the computer 35 as to whether or not a radio wave having a signal intensity equal to or greater than a threshold is currently being output. Therefore, when searching for a specific illegal radio station 10, the computer 35 searches for the illegal radio station 10 in real time based on information on whether or not the illegal radio station 10 is generating jamming radio waves. be able to.

In addition, you may change the said embodiment as follows.
In the above embodiment, the management computer 21 determines that there is a correlation when the waveform of the temporal change in signal strength received by the adjacent base station 15 is the same. The determination of whether or not there is a correlation is not limited to this. For example, the correlation coefficient may be calculated using a statistical function.

Further, by measuring a waveform of a temporal change in signal intensity for a predetermined time, it is possible to determine the correlation by separating the waveforms even with respect to a waveform obtained by combining a plurality of signals. In this case, even if there are a plurality of illegal radio stations 10 that are noise sources, the positions of the illegal radio stations 10 can be estimated.

  In the above embodiment, the management computer 21 specifies the noise source based on the signal strength received from the base station 15 of the three sector cell. However, the management computer 21 may specify the noise source based on the signal strength received from the 6-sector cell base station 15.

  In the above embodiment, when the signal strength received by the base station 15 exceeds the threshold, the signal strength of the base station 15 is observed for a predetermined time, and the waveform of the signal strength obtained by the observation is adjacent. The correlation was determined by comparing the waveform of the signal strength received by the base station 15. At this time, in the above embodiment, the observed predetermined time is about 24 hours, but it may be a short time such as 30 minutes, or may be a long time such as 2 weeks. In the latter case, even the illegal radio station 10 that generates jamming radio waves for a predetermined time every week can be identified.

  In the above embodiment, the management computer 21 obtains the position data of the illegal radio station 10 calculated based on the correlation of the signal strength in the adjacent base station 15 when the signal strength is equal to or greater than the threshold value. Sent to the computer 35. Then, the position of the illegal radio station 10 is specified while the search vehicle 30 travels based on the position data received by the computer 35. For example, in the case of an illegal radio station 10 that generates jamming radio waves for a predetermined time every week, the management computer 21 determines the periodicity of sending the jamming radio waves in the data of the signal intensity data storage unit 22. The generation time of jamming radio waves may be predicted by calculating from the above. Then, the management computer 21 may transmit the generation time of the jamming radio wave and the position of the generation source to the computer 35. As a result, it is possible to more efficiently identify the noise source.

  In the above embodiment, the signal strength received by the base station 15 is measured according to the channel. The present invention is not limited to this, and the present invention can be similarly used even when the signal strength received by the base station 15 is not measured after being separated into channels.

  In the above embodiment, the management computer 21 has a correlation between the signal strengths received by the three base stations 15 at the points A, B, and C from the time t3 to the time t4, and between these points A, B, and C. It was estimated that there was an illegal radio station 10. Not limited to this, the management computer 21 sees a correlation between the signal strengths received by the two base stations 15, for example, only the base stations 15 at the points A and B or only the base stations 15 at the points B and C. In such a case, it may be estimated that the illegal radio station 10 is located between the base stations 15 in which the correlation is seen.

  In the above embodiment, the illegal radio station 10 has been specified and described as a noise source. Not limited to this, the management computer 21 can detect a source of noise that interferes with the communication of the mobile phone terminal 11 other than the illegal radio station 10.

  In the above embodiment, CDMA using the direct spreading method (DSSS) is used as the spread spectrum communication method. The wireless communication method is not limited to this as long as a plurality of base stations 15 receive radio waves of the same channel, and a frequency hopping method (FHSS) may be used.

  In the above embodiment, the mobile phone terminal 11 is used as the communication terminal. For example, a wireless LAN may be used as long as the communication terminal performs a spread spectrum communication method.

The system schematic of embodiment of this invention. Explanatory drawing of the process sequence in this embodiment. Explanatory drawing for demonstrating the position of a noise source. The data explanatory drawing of the signal strength data which the antenna of the base station of the point A received. The data explanatory drawing of the signal strength data which the antenna of the base station of the point B received. The data explanatory drawing of the signal strength data which the antenna of the base station of the point C received.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Illegal radio station as noise generation source, 11 ... Mobile phone terminal as communication terminal, 15 ... Base station, 21 ... Management computer, 35 ... Computer as search device.

Claims (14)

Using a management computer connected to a plurality of base stations that transmit and receive data to and from a plurality of communication terminals by a spread spectrum communication method, a position specifying method for specifying the position of a noise source,
The management computer is
A recording stage for recording the signal strength received by each base station together with its reception time;
An extraction step of extracting a signal strength received by a base station adjacent to the base station at a reception time when the signal strength received by any base station is equal to or greater than a threshold;
An estimation step of estimating a position of the source based on a correlation between signal strengths received by these adjacent base stations.   In the estimation step, when there is a correlation between signal strengths received by adjacent base stations, the location of the source existing between the base stations is estimated based on signals received by these base stations. The position specifying method according to claim 1.   The estimation step estimates a position of the source existing in the vicinity of the base station based on a signal received by the base station when there is no correlation between signal strengths received by adjacent base stations. The position specifying method according to claim 1 or 2.   In the estimation step, an index indicating a correlation between the signal strengths is calculated from the signal strength received by the adjacent base station, and the correlation is determined from the signal strength received by the adjacent base station based on the index. The position specifying method according to claim 1, further comprising a determination step of performing the determination.   5. The position identifying method according to claim 4, wherein the determining step determines a correlation based on a shape of a temporal change in signal strength received by an adjacent base station within a predetermined time. The management computer is connectable via a wireless network with a search device for searching for the generation source,
The said management computer further includes the transmission step which transmits the data regarding the position of the said generation source estimated at the said estimation step to the said search apparatus via the said wireless network. The position specifying method according to one.   The position according to claim 6, wherein the management computer further includes a transmission status transmission step of transmitting a noise reception status at a specific base station to the search device in response to a request from the search device. Identification method. Using a management computer connected to a plurality of base stations that transmit and receive data to and from a plurality of communication terminals by a spread spectrum communication method, a position specifying system that specifies the position of a noise source,
The management computer is
Recording means for recording the signal strength received by each base station together with its reception time;
Extracting means for extracting the signal strength received by the base station adjacent to the base station at the reception time when the signal strength received by any base station is equal to or higher than a threshold;
And an estimation means for estimating the position of the source based on the correlation between the signal strengths received by these adjacent base stations.   When the signal strength received by adjacent base stations has a correlation, the estimation means estimates the position of the source existing between the base stations based on the signals received by these base stations. The position specifying system according to claim 8.   The estimation means estimates the position of the source existing in the vicinity of the base station based on a signal received by the base station when there is no correlation between signal strengths received by adjacent base stations. The position specifying system according to claim 8 or 9, characterized in that:   The estimation means calculates an index indicating a correlation between these signal strengths from the signal strength received by the adjacent base station, and determines a correlation with the signal strength received by the adjacent base station based on the index. The position specifying system according to any one of claims 8 to 10, further comprising a determination unit that performs determination.   The position determination system according to claim 11, wherein the determination unit determines a correlation based on a shape of a temporal change in signal strength received by an adjacent base station within a predetermined time. The management computer is connectable via a wireless network with a search device for searching for the generation source,
The said management computer further contains the transmission means which transmits the data regarding the position of the said generation source estimated by the said estimation means to the said search apparatus via the said wireless network. A location system according to claim 1.   The position according to claim 13, wherein the management computer further includes a transmission status transmission means for transmitting a reception status of noise at a specific base station to the search device in response to a request from the search device. Specific system.

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