Radio signal observation system, radio signal observation method, and control device

Abstract

A radio signal observation system for observing frequency spectra of radio signals comprises: a first spectrum analyzer that observes frequency spectra of radio signals in a first bandwidth; one or multiple second spectrum analyzers that observe frequency spectra of radio signals in a second bandwidth; and a control device that controls the one or more second spectrum analyzers. The control device is configured to execute: processing to calculate, on the basis of information about the frequency spectra observed by the first spectrum analyzer, a specific standby period during which radio signals are not observed by the first spectrum analyzer or a time occupancy is equal to or less than a predetermined value; and processing to select a second bandwidth for each of the one or more second spectrum analyzers so as to perform observation for a specific bandwidth.

Description

[Technical field]

[0001] The present disclosure relates to techniques for observing the frequency spectrum of a radio signal. [Background technology]

[0002] In recent years, there are many cases where various wireless communication systems share the same frequency band. For example, in domestic unlicensed bands, there is a regulation that wireless communication devices must use carrier sense (or listen-before-talk) to check for nearby transmission signals for a certain period of time before starting transmission, and this is used as a coexistence technology between different wireless communication systems.

[0003] However, when multiple wireless communication systems coexist in the same frequency band, the frequency utilization efficiency is reduced due to frame collisions and the like, compared to when the systems are not mixed, even if coexistence techniques such as carrier sense are used. Therefore, in order to maximize the frequency utilization efficiency, it is important to understand the frequency band mixture and appropriately select the channel to be used. In addition, in order to appropriately select a channel when multiple wireless communication systems use the same frequency band, it is considered effective to observe wireless signals in a wide band using a spectrum analyzer or software defined radio (SDR) (see Non-Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] A-Train Co., Ltd., "Introducing the best Wi-Fi spectrum analyzer for in-home troubleshooting", p.18 (AP scan (network detection)), http: / / www.taketheatrain.co.jp / wp-content / uploads / 2018 / 10 / WiFi spectrum analyzer "WX150" materials (download / 3MB).pdf (October 5, 2018) [Non-Patent Document 2] Yotaro Umeda, "High-speed and high-dynamic-range wideband spectrum detection using multi-stage detection method", Telecommunications Advancement Foundation Research and Investigation Grant Report, No. 26, 2011, https: / / www.taf.or.jp / files / items / 539 / File / P322.pdf [Non-Patent Document 3] Takeshi Okamoto et al., "Introduction of Wireless LAN Testers for Smooth Provision of WiFi Services," Institute of Electronics, Information and Communication Engineers, Communications Society Magazine, No. 25, pp. 38-43 (2013) Summary of the Invention [Problem to be solved by the invention]

[0005] When observing wireless signals in a wide band using a spectrum analyzer or SDR, it is necessary to spend more time on each scan than when observing wireless signals in a narrow band. On the other hand, if each scan takes a long time, there is a possibility that wireless signals with short lengths will not be captured, so in order to observe accurately, it is necessary to perform multiple scans or to reduce the frequency accuracy (widen the resolution band width (RBW)) and perform the scan in a short time.

[0006] However, when scanning multiple times, the number of scans must be increased according to the transmission frequency of the wireless communication system, which means it takes a very long time to complete the observation. Also, if the frequency accuracy is reduced, there is a risk that the wireless signals transmitted in narrow bands cannot be observed accurately. For example, in heterogeneous wireless systems, the bandwidth difference is up to nearly 40 times in the 920 MHz band, making it difficult to observe accurately in one go.

[0007] However, the use of a high-speed, high-dynamic-range spectrum analyzer is limited to a limited environment due to costs, availability, productivity, etc. In addition, a multi-stage detection method is proposed in Non-Patent Document 2, but since the next stage is performed after the previous stage is completed, it takes time to grasp the situation when multiple wireless communication systems are mixed. In addition, it is difficult to respond to the case where the frequency usage situation of multiple wireless communication systems varies with time.

[0008] One object of the present disclosure is to provide a technique for appropriately observing wideband wireless signals without degrading frequency accuracy. Another object of the present disclosure is to provide a technique for agilely responding to time-varying frequency usage conditions of multiple wireless communication systems. [Means for solving the problem]

[0009] The first disclosure relates to a radio signal observation system that observes the frequency spectrum of a radio signal. A radio signal observation system according to a first disclosure includes a first spectrum analyzer that observes the frequency spectrum of the radio signal in a first bandwidth, one or more second spectrum analyzers that observe the frequency spectrum of the radio signal in a second bandwidth narrower than the first bandwidth, and a control device that controls the one or more second spectrum analyzers, where the resolution bandwidth of the one or more second spectrum analyzers is set narrower than the resolution bandwidth of the first spectrum analyzer. The control device is configured to execute a process of acquiring spectral information of the frequency spectrum observed by the first spectrum analyzer, a specific band calculation process of calculating, based on the spectral information, a specific band in which the radio signal is not observed in the first spectrum analyzer or the time occupancy rate of the radio signal is equal to or less than a predetermined value, and a selection process of selecting the second bandwidth of each of the one or more second spectrum analyzers so as to observe the specific band.

[0010] The second disclosure relates to a radio signal monitoring system having the following features in addition to the radio signal monitoring system according to the first disclosure. The selection process includes frequency-dividing or time-dividing the specific band and selecting the second bandwidth of each of the one or more second spectrum analyzers to assign each of the one or more second spectrum analyzers to the frequency division or the time division.

[0011] The third disclosure relates to a radio signal monitoring system having the following features in addition to the radio signal monitoring system according to the first or second disclosure. The control device is configured to detect a change in the channel of the radio signal observed by the first spectrum analyzer based on the spectrum information, and, upon detection of the change in the channel, execute the specific band calculation process and the selection process.

[0012] The fourth disclosure relates to a wireless signal monitoring system according to any one of the first to third disclosures, and further relates to a wireless signal monitoring system having the following features. The control device is further configured to execute a process of acquiring a utilization frequency band of a specific wireless terminal, and the specific band calculation process includes not determining the utilization frequency band as the specific band.

[0013] The fifth disclosure relates to a radio signal observation method for observing the frequency spectrum of a radio signal by using a plurality of spectrum analyzers. Here, the plurality of spectrum analyzers include a first spectrum analyzer that observes the frequency spectrum of the radio signal in a first bandwidth, and one or more second spectrum analyzers that observe the frequency spectrum of the radio signal in a second bandwidth narrower than the first bandwidth, and a resolution bandwidth of the first or second spectrum analyzer is set narrower than the resolution bandwidth of the first spectrum analyzer. A radio signal observation method according to a fifth disclosure includes acquiring spectral information of the frequency spectrum observed by the first spectrum analyzer, calculating a specific band in which the radio signal is not observed in the first spectrum analyzer or the time occupancy rate of the radio signal is equal to or less than a predetermined value based on the spectral information, and selecting the second bandwidth of each of the one or more second spectrum analyzers so that observation is performed on the specific band.

[0014] The sixth disclosure relates to a radio signal observation method having the following characteristics in addition to the radio signal observation method according to the fifth disclosure. Selecting the second bandwidth includes frequency-dividing or time-dividing the specific band and selecting the second bandwidth of each of the one or more second spectrum analyzers to assign each of the one or more second spectrum analyzers to the frequency division or the time division.

[0015] The seventh disclosure relates to a control device that controls a plurality of spectrum analyzers that observe the frequency spectrum of a radio signal. Here, the plurality of spectrum analyzers include a first spectrum analyzer that observes the frequency spectrum of the radio signal in a first bandwidth, and one or more second spectrum analyzers that observe the frequency spectrum of the radio signal in a second bandwidth narrower than the first bandwidth, and a resolution bandwidth of the first or second spectrum analyzer is set narrower than the resolution bandwidth of the first spectrum analyzer. The control device according to the seventh disclosure executes a process of acquiring spectral information of the frequency spectrum observed by the first spectrum analyzer, a specific band calculation process of calculating, based on the spectral information, a specific band in which the radio signal is not observed in the first spectrum analyzer or the time occupancy rate of the radio signal is equal to or lower than a predetermined value, and a selection process of selecting the second bandwidth of each of the one or more second spectrum analyzers so as to observe the specific band.

[0016] The eighth disclosure relates to a control device further having the following features in addition to the control device according to the seventh disclosure. The selection process includes frequency-dividing or time-dividing the specific band and selecting the second bandwidth of each of the one or more second spectrum analyzers to assign each of the one or more second spectrum analyzers to the frequency division or the time division. Effect of the Invention

[0017] According to the present disclosure, a first spectrum analyzer observes the frequency spectrum of a radio signal having a high time occupancy rate in a wide band, and one or more second spectrum analyzers each observe the frequency spectrum of a radio signal in a narrow band for a specific band that requires more detailed confirmation in parallel with the first spectrum analyzer. Here, the resolution bandwidth of the second spectrum analyzer is set narrower than the resolution bandwidth of the first spectrum analyzer. This makes it possible to properly observe a wideband radio signal without degrading frequency accuracy.

[0018] Furthermore, since each of the one or more second spectrum analyzers does not need to wait for the results of observation by the first spectrum analyzer, it is possible to flexibly respond to changes in frequency usage conditions of multiple wireless communication systems. [Brief description of the drawings]

[0019] [Figure 1] 1 is a block diagram showing a schematic configuration of a radio signal observation system according to an embodiment of the present invention. [Diagram 2] 4 is a graph showing an example of a frequency spectrum of a radio signal observed by a first spectrum analyzer and one or more second spectrum analyzers. [Diagram 3] FIG. 11 is a conceptual diagram for explaining an overview of a specific band calculation process. [Figure 4] FIG. 11 is a conceptual diagram for explaining an overview of a selection process. [Diagram 5] FIG. 2 is a block diagram showing a schematic configuration of a control device. [Figure 6] 4 is a flowchart showing a radio signal observation method implemented by the radio signal observation system according to the present embodiment. [Figure 7] FIG. 13 is a block diagram showing a schematic configuration of a radio signal observation system according to a modified example. [Figure 8] 1 is a graph showing an example of a frequency band used by a specific wireless terminal. [Figure 9] 10 is a flowchart showing a radio signal observation method implemented by a radio signal observation system according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. However, when the number, quantity, amount, range, etc. of each element is mentioned in the embodiments shown below, the idea of ​​the present disclosure is not limited to the mentioned number unless it is specifically stated or the number is clearly specified in principle. Furthermore, the configurations etc. described in the embodiments shown below are not necessarily essential to the idea of ​​the present disclosure unless it is specifically stated or the number is clearly specified in principle. In addition, the same reference numerals are attached to the same or corresponding parts in each drawing, and the duplicated explanation is appropriately simplified or omitted.

[0021] 1. Overview of the radio signal observation system FIG. 1 is a block diagram showing a schematic configuration of a radio signal observation system 10 according to this embodiment. The radio signal observation system 10 includes a first spectrum analyzer 100, one or more second spectrum analyzers 200 (#1-#N), and a control device 300. Here, N is an integer and indicates the number of second spectrum analyzers 200 included in the radio signal observation system 10. However, N may be 1. The control device 300 is connected to the first spectrum analyzer 100 and the one or more second spectrum analyzers 200 so that information can be transmitted between them. For example, they are electrically connected via a cable. However, the information may be transmitted indirectly via a relay device.

[0022] Each of the first spectrum analyzer 100 and the one or more second spectrum analyzers 200 observes the frequency spectrum of a radio signal in a predetermined bandwidth. Hereinafter, the predetermined bandwidth related to the first spectrum analyzer 100 is referred to as the "first bandwidth," and the predetermined bandwidth related to the one or more second spectrum analyzers 200 is referred to as the "second bandwidth." Hereinafter, the second bandwidth for each of the one or more second spectrum analyzers 200 may be different from each other.

[0023] Each of the one or more second spectrum analyzers 200 is configured to be able to select the second bandwidth by the control device 300 described later. For example, each of the one or more second spectrum analyzers 200 is configured to obtain a selection request for the second bandwidth as a control signal output by the control device 300, and update parameter information defining the second selection width according to the control signal. In particular, as described later, the second bandwidth is selected to be narrower than the first bandwidth and included in the first bandwidth. That is, the first spectrum analyzer 100 observes the frequency spectrum of the radio signal in a wide band, and the one or more second spectrum analyzers 200 observe the frequency spectrum of the radio signal in a narrow band in parallel with the first spectrum analyzer 100.

[0024] The first bandwidth may be given as a fixed value, or may be configured to be selectable by the control device 300. Alternatively, the first bandwidth may be configured to receive a user's operation from an input unit included in the first spectrum analyzer 100 or an input terminal (such as a switch, a touch panel, or a keyboard) not shown in Fig. 1, and to select the first bandwidth in response to the operation.

[0025] The first spectrum analyzer 100 and one or more second spectrum analyzers 200 may be equivalent to a known sweep-type spectrum analyzer with respect to other parts of the above-mentioned functions (algorithms and configurations for observing the frequency spectrum of a radio signal). That is, the frequency spectrum of a radio signal is observed by executing a scan with a resolution band width (RBW) set for a predetermined bandwidth. Typically, the spectrum analyzer includes an attenuator, a local oscillator, a mixer, an IF filter, a detector, and a sweep generator. In particular, the first spectrum analyzer 100 and one or more second spectrum analyzers 200 may be a simple spectrum analyzer.

[0026] In the radio signal observation system 10 according to this embodiment, the RBW of the one or more second spectrum analyzers 200 is set narrower than the RBW of the first spectrum analyzer 100. In other words, the frequency accuracy of the one or more second spectrum analyzers 200 is higher than the frequency accuracy of the first spectrum analyzer 100. The second bandwidth is selected to be narrower than the first bandwidth and included in the first bandwidth, so that the one or more second spectrum analyzers 200 can observe the frequency spectrum of the radio signal in more detail for a part of the frequency bands in the first bandwidth.

[0027] Incidentally, in the radio signal observation system 10 according to the present embodiment, the second bandwidth is selected to be narrower than the first bandwidth. Therefore, if the RBW of the first spectrum analyzer 100 and the RBW of the one or more second spectrum analyzers 200 are the same, the sweep speed of the first spectrum analyzer 100 is slower than the sweep speed of the one or more second spectrum analyzers 200 (the time required for scanning in the first spectrum analyzer 100 is longer than the time required for scanning in the one or more second spectrum analyzers 200). In other words, when the RBW of the one or more second spectrum analyzers 200 is set within a range in which the sweep speed of the one or more second spectrum analyzers 200 is not slower than the sweep speed of the first spectrum analyzer 100, the first spectrum analyzer 100 observes the frequency spectrum of a radio signal that is wideband and has a long occupancy time, and the one or more second spectrum analyzers 200 observes the frequency spectrum of a radio signal (e.g., a short packet) that is narrowband and has a short time occupancy rate.

[0028] The RBW of one or more second spectrum analyzers may be set as a fixed value, or may be set by the control device 300 based on the first bandwidth, the RBW of the first spectrum analyzer 100, the selected second bandwidth, etc. For example, the control device 300 sets the RBW of one or more second spectrum analyzers 200 according to the selected second bandwidth within a range not slower than the sweep speed of the first spectrum analyzer 100.

[0029] FIG. 2 shows an example of a frequency spectrum of a radio signal observed by the first spectrum analyzer 100 and a frequency spectrum of a radio signal observed by one or more second spectrum analyzers 200. FIG. 2 shows a frequency spectrum graph with frequency on the horizontal axis and signal strength on the vertical axis for each of the first spectrum analyzer 100 and one or more second spectrum analyzers 200. Here, for one or more second spectrum analyzers 200, graphs of frequency spectra with different second bandwidths are shown as (A), (B), and (C). This is, for example, a frequency spectrum of a radio signal observed by three second spectrum analyzers 200 with different second bandwidths selected. Note that f0, f1, . . . , f10 shown in FIG. 2 each indicate a frequency. That is, in FIG. 2, the first bandwidth is equal to or greater than f0 and equal to or less than f10. Also, (A), (B), and (C) are examples of frequency spectra observed when the second bandwidth is selected as band A (f0 or more and f1 or less), band B (f8 or more and f9 or less), and band C (f9 or more and f10 or less), respectively.

[0030] As shown in FIG. 2, a first spectrum analyzer 100 observes the frequency spectrum of a radio signal in a wide band, and one or more second spectrum analyzers 200 observe the frequency spectrum of the radio signal in a narrow band included in the first bandwidth in parallel with the first spectrum analyzer 100.

[0031] Furthermore, the one or more second spectrum analyzers 200 observe the frequency spectrum in the narrow second bandwidth set for each of them with higher frequency accuracy (narrower RBW than the first spectrum analyzer) than the first spectrum analyzer 100. This allows the one or more second spectrum analyzers to observe radio signals that could not be captured by the first spectrum analyzer 100 due to its low frequency accuracy, as shown in Fig. 2(A).

[0032] The first spectrum analyzer 100 and one or more second spectrum analyzers 200 may be used by a wireless communication terminal to grasp the usage status and interference status of the surrounding frequency bands, or may be used by a user to grasp the usage status and interference status of the surrounding frequency bands. In the former case, for example, the first spectrum analyzer 100 and one or more second spectrum analyzers 200 output the observation result of the frequency spectrum of the surrounding wireless signal to the wireless communication terminal. Then, the wireless communication terminal selects a channel according to the usage status to transmit the wireless signal, or grasps the interference status of the wireless signal being transmitted. In the latter case, for example, the first spectrum analyzer 100 and one or more second spectrum analyzers 200 include an input unit that accepts user operations and a display unit that displays the frequency spectrum of the observed wireless signal. Then, the user sets the first bandwidth and the RBW of the first spectrum analyzer 100 by operating the input unit, and grasps the usage status and interference status of the surrounding frequency bands by checking the display unit.

[0033] Referring again to FIG. 1, the control device 300 controls one or more second spectrum analyzers 200. The control device 300 performs control by operating one or more second spectrum analyzers 200 according to a control signal output by the control device 300. Here, the control signal is generated by a process executed in the control device 300. In particular, the control device 300 executes a process related to the selection of a second bandwidth for each of the one or more second spectrum analyzers 200. The process related to the selection of the second bandwidth executed in the control device 300 is also referred to as a "second bandwidth selection process." An overview of the second bandwidth selection process will be described below.

[0034] First, in the second bandwidth selection process, information on the frequency spectrum observed by the first spectrum analyzer 100 (hereinafter also referred to as "spectral information") is acquired, and based on the spectral information, a frequency band in which no radio signal is observed by the first spectrum analyzer 100 or in which the time occupancy rate of the radio signal is equal to or less than a predetermined value is calculated as a specific band (specific band calculation process).

[0035] FIG. 3 is a conceptual diagram for explaining an outline of the specific band calculation process. In FIG. 3, (A), (B), (C), (D), and (E) are shown as examples of frequency spectra observed by the first spectrum analyzer 100 in time series in this order. Now, assume that the control device 300 acquires spectrum information corresponding to the frequency spectrum shown in FIG. 3. For example, the control device 300 detects a frequency band in which no wireless signal is observed or in which the time occupancy rate of a wireless signal is a predetermined value or less, depending on whether the signal strength is equal to or greater than a threshold. In the example shown in FIG. 3, no wireless signal with a signal strength equal to or greater than a threshold is observed in the frequency bands f0 to f2 and f8 to f10. In addition, in the frequency bands f2 to f3, wireless signals with a signal strength equal to or greater than a threshold are observed except for (A) and (D), and in the frequency bands f6 to f7, a wireless signal with a signal strength equal to or greater than a threshold is observed only in (C). That is, in the example shown in Fig. 3, the time occupancy rate of wireless signals observed in the frequency band from f2 to f3 is 60%, and the time occupancy rate of wireless signals observed in the frequency band from f6 to f7 is 20%. For example, if the predetermined value related to the time occupancy rate is 50%, in the example shown in Fig. 3, the control device 300 calculates the frequency band from f0 to f2, the frequency band from f6 to f7, and the frequency band from f8 to f10 as the specific bands.

[0036] The time occupancy rate may be given for the spectrum information acquired at each predetermined period, or may be recalculated and given each time the spectrum information is acquired.

[0037] Next, in the second bandwidth selection process, the second bandwidth of each of the one or more second spectrum analyzers 200 is selected so as to perform observation on the specific band (selection process). Here, the selection process divides the specific band into frequency or time divisions, and selects the second bandwidth of each of the one or more second spectrum analyzers 200 so as to assign each of the one or more second spectrum analyzers 200 to the frequency division or time division.

[0038] FIG. 4 is a conceptual diagram for explaining an outline of the selection process. In FIG. 4, as in the case described in FIG. 3, it is assumed that a frequency band from f0 to f2, a frequency band from f6 to f7, and a frequency band from f8 to f10 are calculated as specific bands. Also, it is assumed that the wireless signal observation system 10 includes three second spectrum analyzers 200 (#1, #2, #3). In the example shown in FIG. 4, the control device 300 divides the specific band into band A (f0 to f1), band B (f1 to f2), band C (f3 to f4), band D (f6 to f7), band E (f8 to f9), and band F (f9 to f10) as shown in the upper part of FIG. 4. Next, as shown in the lower part of FIG. 4, each band is time-divided and a second bandwidth is selected so as to be assigned to each of the second spectrum analyzers 200. For example, for the second spectrum analyzer 200 #1, the control device 300 selects band A as the second bandwidth from time t0 to t1, selects band B as the second bandwidth from time t1 to time t2, and repeats this process thereafter.

[0039] The control device 300 may be configured to select the second bandwidth by performing only frequency division of a specific band. In this case, the second bandwidth may be selected so that the one or more second spectrum analyzers 200 are equally divided, or the second bandwidth of each of the one or more second spectrum analyzers 200 may be selected so that the frequency-divided bands are assigned in descending order of priority.

[0040] The control device 300 outputs a control signal to each of the one or more second spectrum analyzers 200 so as to select the second bandwidth by the second bandwidth selection process.

[0041] By executing the second bandwidth selection process in the control device 300 in this manner, the second bandwidth of each of the one or more second spectrum analyzers 200 is included in a specific band within the first bandwidth in which no radio signal is observed or in which the time occupancy rate of the radio signal is equal to or less than a predetermined value in the first spectrum analyzer 100. In other words, according to the radio signal observation system 10 of this embodiment, while the first spectrum analyzer 100 observes the frequency spectrum of a radio signal having a high time occupancy rate in a wide band, in parallel, each of the one or more second spectrum analyzers 200 observes the frequency spectrum of the radio signal in a narrow band for a specific band that requires detailed confirmation.

[0042] The control device 300 is also configured to detect a change in the channel of the radio signal observed by the first spectrum analyzer 100 based on the spectrum information, and execute a specific band calculation process and a selection process in response to the detection of the channel change. Here, the detection of the channel change is performed, for example, when a radio signal is detected in a frequency band where no radio signal was observed by the first spectrum analyzer 100. Alternatively, the detection of the channel change is performed when a radio signal is no longer detected in a frequency band where a radio signal was observed by the first spectrum analyzer 100.

[0043] In this manner, by configuring the specific band calculation process and selection process to be executed in response to detection of a channel change, it is possible to prevent the second bandwidth selection process from being executed unnecessarily.

[0044] 2.Control device configuration The following describes the configuration of the control device 300. Fig. 5 is a block diagram showing a schematic configuration of the control device 300. The control device 300 includes one or more storage devices 310 and one or more processors 320.

[0045] The one or more storage devices 310 store a control program 311 executable by the one or more processors 320, and control information 312 required for processing executed by the one or more processors 320. Examples of the one or more storage devices 310 include a volatile memory, a non-volatile memory, a HDD, and an SSD. Information acquired by the control device 300 is stored as control information 312 in the one or more storage devices 310.

[0046] The control program 311 includes a program related to the execution of the second bandwidth selection process. Examples of the control information 312 include spectrum information acquired from the first spectrum analyzer 100 and parameter information related to the control program 311 (such as a threshold value related to the specific band calculation process). The control program 311 may be provided through a network.

[0047] The one or more processors 320 read the control program 311 and the control information 312 from the one or more storage devices 310, and execute processing in accordance with the control program 311 based on the control information 312. Thereby, a second bandwidth selection process is executed, and a control signal for selecting the second bandwidth of each of the one or more second spectrum analyzers 200 is generated.

[0048] 3. Radio signal observation method Hereinafter, a radio signal observation method realized by the radio signal observation system 10 according to this embodiment will be described. Fig. 6 is a flowchart showing the radio signal observation method realized by the radio signal observation system 10 according to this embodiment. The flowchart shown in Fig. 6 is started after a request to start observation of a radio signal is accepted by operating an input terminal, for example. Furthermore, each process is executed at a predetermined processing cycle.

[0049] In step S100, the first spectrum analyzer 100 and each of the one or more second spectrum analyzers 200 perform a scan to observe the frequency spectrum of a radio signal. Then, the control device 300 obtains spectrum information from the first spectrum analyzer 100.

[0050] After step S100, the process proceeds to step S200.

[0051] In step S200, the control device 300 detects whether or not there has been a change in the channel of the radio signal observed by the first spectrum analyzer 100, based on the spectrum information.

[0052] If there has been a change in channel (step S200; Yes), the process proceeds to step S300. If there has been no change in channel (step S200: No), the process returns to step S100, and the scan is executed again to continue the observation.

[0053] In step S300, the control device 300 executes a specific band calculation process based on the spectrum information acquired in step S100 to calculate a specific band.

[0054] After step S300, the process proceeds to step S400.

[0055] In step S400, the control device 300 executes a selection process according to the specific band calculated in step S300, and selects a second bandwidth for each of the one or more second spectrum analyzers 200. Then, the control device 300 outputs a control signal to each of the one or more second spectrum analyzers 200 so that the selected second bandwidth is obtained.

[0056] After step S400, the process proceeds to step S500.

[0057] In step S500, each of the first spectrum analyzer 100 and one or more second spectrum analyzers 200 judges whether to end the observation. This is judged, for example, based on whether a request to end the observation is received by operating an input terminal. If the observation is not to be ended (step S500; No), the process returns to step S100 and the observation is continued by executing a scan again.

[0058] 4.Effects As described above, according to this embodiment, the first spectrum analyzer 100 observes the frequency spectrum of a radio signal having a high time occupancy rate in a wide band, and each of the one or more second spectrum analyzers 200 observes the frequency spectrum of the radio signal in a narrow band for a specific band that requires more detailed confirmation in parallel with the first spectrum analyzer 100. Here, the RBW of the second spectrum analyzer 200 is narrower than that of the first spectrum analyzer 100 (the frequency accuracy of the second spectrum analyzer 200 is higher than that of the first spectrum analyzer 100). This makes it possible to appropriately observe a wideband radio signal without degrading the frequency accuracy. This in turn contributes to speeding up the observation of the radio signal.

[0059] Furthermore, since each of the one or more second spectrum analyzers 200 does not need to wait for the observation result of the first spectrum analyzer 100, it is possible to flexibly respond (perform second bandwidth selection processing) when there is a time fluctuation in the frequency usage status of the multiple wireless communication systems (step S200 shown in FIG. 6; Yes).

[0060] 5. Variations The radio signal observation system 10 according to this embodiment may adopt the following modified aspects. In the following description, parts that overlap with the above content will be omitted as appropriate.

[0061] The control device 300 may be configured to acquire a frequency band used by a specific wireless terminal (e.g., a wireless LAN terminal) and not to set the acquired frequency band as a specific band in the specific band calculation process. Here, the frequency band used can be rephrased as a "channel" used by the specific wireless terminal.

[0062] Fig. 7 is a block diagram showing a schematic configuration of a radio signal observation system 10 according to a modified example. Compared to the radio signal observation system 10 shown in Fig. 1, the radio signal observation system 10 according to the modified example includes a radio communication device 400. The control device 300 is connected to the radio communication device 400 so as to be able to transmit information to and from the radio communication device 400.

[0063] The wireless communication device 400 is configured to be able to communicate with a specific wireless terminal located in the vicinity. The wireless communication device 400 acquires the usage frequency band of the specific wireless terminal through communication. For example, a beacon transmitted by the specific wireless terminal is detected, and the usage frequency band is acquired by a demodulator included in the wireless communication device 400. Then, the control device 300 acquires the usage frequency band of the specific wireless terminal from the wireless communication device 400.

[0064] Fig. 8 shows an example of the frequency bands used by specific wireless terminals (wireless terminal A and wireless terminal B). In the example shown in Fig. 8, the frequency band used by wireless terminal A is from near f1 to desired f2, and the frequency band used by wireless terminal B is from near f6 to near f7.

[0065] In the specific band calculation process, the control device 300 calculates the specific band so as not to include the utilization frequency band acquired from the wireless communication device 400. For example, when spectrum information is acquired as described in Fig. 3 and the utilization frequency band is acquired as described in Fig. 8, the specific band excludes the utilization frequency bands of wireless terminals A and B, and becomes a frequency band from f0 to f1 and a frequency band from f8 to f10.

[0066] Fig. 9 shows a radio signal observation method realized by a radio signal observation system 10 according to a modified example. As shown in Fig. 9, in the radio signal observation method according to the modified example, after determining that there is a channel change (step S200; Yes), the control device 300 executes a process of acquiring the frequency band used by a specific radio terminal (step S210). Then, in step S300, the control device 300 executes a specific band calculation process based on the spectrum information acquired in step S100 and the frequency band used in step S210, and calculates the specific band.

[0067] By adopting such a modified embodiment, it is possible to know in advance the frequency bands in which many wireless terminals exist, and by extension, it is possible to prevent a bandwidth that does not require detailed confirmation from being selected as the second bandwidth because the time occupancy rate of the frequency band is low and no wireless signals are observed in the first spectrum analyzer 100, even though the frequency band does not need confirmation because many wireless terminals use the frequency band. [Explanation of symbols]

[0068] 10. Radio Signal Observation System 100 1st Spectrum Analyzer 200 Second Spectrum Analyzer 300 Control device 310 Storage device 311 Control Program 312 Control Information 320 Processor 400 Wireless communication device

Claims

1. A radio signal observation system for observing a frequency spectrum of a radio signal, comprising: a first spectrum analyzer for observing the frequency spectrum of the radio signal over a first bandwidth; one or more second spectrum analyzers for observing the frequency spectrum of the radio signal in a second bandwidth narrower than the first bandwidth; a control device that controls the one or more second spectrum analyzers; Equipped with a resolution bandwidth of the one or more second spectrum analyzers is set to be narrower than a resolution bandwidth of the first spectrum analyzer; The control device includes: obtaining spectrum information of the frequency spectrum observed by the first spectrum analyzer; a specific band calculation process for calculating a specific band in which the wireless signal is not observed by the first spectrum analyzer or in which a time occupancy rate of the wireless signal is equal to or less than a predetermined value based on the spectrum information; a selection process for selecting the second bandwidth of each of the one or more second spectrum analyzers so as to perform observations on the specific band; It is configured to run A radio signal observation system comprising:

2. 2. The radio signal observation system according to claim 1, The selection process includes frequency-dividing or time-dividing the specific band, and selecting the second bandwidth of each of the one or more second spectrum analyzers so as to assign each of the one or more second spectrum analyzers to the frequency division or the time division. A radio signal observation system comprising:

3. 3. The radio signal observation system according to claim 1, The control device is configured to detect a change in a channel of the radio signal observed by the first spectrum analyzer based on the spectrum information, and to execute the specific band calculation process and the selection process in response to detection of the change in the channel. A radio signal observation system comprising:

4. 4. The radio signal observation system according to claim 1, The control device is further configured to execute a process of acquiring a frequency band used by a specific wireless terminal; The specific band calculation process includes not determining the utilization frequency band as the specific band. A radio signal observation system comprising:

5. A radio signal observation method for observing a frequency spectrum of a radio signal by a plurality of spectrum analyzers, comprising: the plurality of spectrum analyzers include a first spectrum analyzer that observes the frequency spectrum of the radio signal in a first bandwidth, and one or more second spectrum analyzers that observe the frequency spectrum of the radio signal in a second bandwidth narrower than the first bandwidth, a resolution bandwidth of the one or more second spectrum analyzers is set to be narrower than a resolution bandwidth of the first spectrum analyzer; The radio signal observation method includes: acquiring spectrum information of the frequency spectrum observed by the first spectrum analyzer; calculating a specific band in which the wireless signal is not observed by the first spectrum analyzer or in which a time occupancy rate of the wireless signal is equal to or less than a predetermined value based on the spectrum information; selecting the second bandwidth of each of the one or more second spectrum analyzers such that observations are made over the particular band; Includes A radio signal observation method comprising:

6. 6. The radio signal observation method according to claim 5, Selecting the second bandwidth includes frequency-dividing or time-dividing the specific band and selecting the second bandwidth of each of the one or more second spectrum analyzers to assign each of the one or more second spectrum analyzers to the frequency division or the time division. A radio signal observation method comprising:

7. A control device for controlling a plurality of spectrum analyzers for observing a frequency spectrum of a radio signal, comprising: the plurality of spectrum analyzers include a first spectrum analyzer that observes the frequency spectrum of the radio signal in a first bandwidth, and one or more second spectrum analyzers that observe the frequency spectrum of the radio signal in a second bandwidth narrower than the first bandwidth, a resolution bandwidth of the one or more second spectrum analyzers is set to be narrower than a resolution bandwidth of the first spectrum analyzer; The control device includes: obtaining spectrum information of the frequency spectrum observed by the first spectrum analyzer; a specific band calculation process for calculating a specific band in which the wireless signal is not observed by the first spectrum analyzer or in which a time occupancy rate of the wireless signal is equal to or less than a predetermined value based on the spectrum information; a selection process for selecting the second bandwidth of each of the one or more second spectrum analyzers so as to perform observations on the specific band; Run A control device comprising:

8. The control device according to claim 7, The selection process includes frequency-dividing or time-dividing the specific band, and selecting the second bandwidth of each of the one or more second spectrum analyzers so as to assign each of the one or more second spectrum analyzers to the frequency division or the time division. A control device comprising:

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