JP2013115504A - Signal processing device and signal processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a frequency resolution while considering an influence of a processing load in frequency analysis, and to improve the accuracy of detection of a radio communication method to perform signal processing of radio communication.SOLUTION: A signal processing device performs signal processing of reception signals by a plurality of radio communication methods different from each other, and comprises: frequency resolution control means for determining the FFT point number of Fourier transformation on the basis of the computing capability of the signal processing device and a frequency bandwidth which is an object of signal detection; frequency band extraction means which Fourier transforms the reception signal on the basis of the determined FFT point number, extracts a frequency band about which reception power in the frequency region is larger than a prescribed value, and outputs information on the extracted frequency band; radio communication method estimation means which estimates a radio communication method used at the frequency band on the basis of the information on the frequency band and the reception signal; and demodulation means which loads a software program corresponding to the estimated radio communication method and performs demodulation processing of the reception signal by use of the software program.

Description

  The present invention relates to a software radio reception apparatus that receives a plurality of radio communication system signals superimposed on each other and performs demodulation processing of each radio communication system within the same apparatus. The present invention relates to a signal processing apparatus and a signal processing method for detecting and performing signal processing of wireless communication.

  In recent years, there are many users who use a wireless LAN as an indoor network that connects to an optical line from a home or office, regardless of the connection location. In addition, wireless that is used depending on the purpose, such as using Bluetooth (registered trademark), Zigbee (registered trademark), and extra-small radio, which is more power-saving in ubiquitous M2M (Machine-to-Machine) communication, is considered. Diversification of communication methods is progressing. When operating a plurality of wireless communication systems in the same apparatus so far, signals are extracted using BPFs (bandpass filters) for all wireless communication systems by arranging the demodulation units of the respective wireless communication systems in parallel. A configuration for demodulating later was assumed.

  However, when such a configuration is used in the software defined radio apparatus, the BPF for each band operates even when there is no received signal, so that the processing load on the CPU (Central Processing Unit) increases, and further, the frequency change and demodulation unit There are problems such as being unable to handle new registrations.

  To solve this problem, even if signals of different wireless communication systems are superimposed and received, the demodulating process is performed without increasing the processing load. Therefore, the analog-digital converted received signal is analyzed. A technique is known in which a wireless communication method is selected from the analysis result, and only the selected wireless communication method is demodulated (see, for example, Patent Document 1). Since this technology operates only the demodulation processing of the corresponding wireless communication system, it can be expected to minimize the increase in arithmetic processing.

JP 2010-278619 A

  By the way, in the prior art, FFT (Fast Fourier Transform) is used as a method of analyzing the use frequency and bandwidth in the feature analysis of the received signal, but the frequency resolution changes depending on the number of FFT points and the sampling interval. Therefore, if the number of FFT points is increased with a constant sampling interval, the frequency resolution decreases and the use frequency and bandwidth can be detected accurately, but the processing load and processing delay increase. On the other hand, if the number of FFT points is reduced, the processing load is reduced, but the frequency resolution becomes coarse, so that the detection accuracy of the wireless communication system with a small bandwidth is deteriorated. Also, if the sampling interval is widened, the frequency resolution can be reduced while maintaining the processing load, but the range of frequencies to be detected is narrowed. Thus, the conventional technique has a problem that it is difficult to achieve both processing load and detection accuracy.

  The present invention has been made in view of such circumstances, and a signal processing apparatus and signal processing capable of performing signal processing of wireless communication by controlling frequency resolution and improving the accuracy of detection of a wireless communication system. It aims to provide a method.

  The present invention is a signal processing device that performs signal processing of received signals by a plurality of different wireless communication schemes, and performs Fourier transform based on the calculation capability of the signal processing device and the frequency bandwidth that is the target of signal detection. Frequency resolution control means for determining the number of FFT points, Fourier transform of the received signal based on the determined number of FFT points, extracting a frequency band in which the received power in the frequency domain is greater than a predetermined value, and extracting the frequency A frequency band extracting unit that outputs band information; a radio communication scheme estimating unit that estimates a radio communication scheme used in the frequency band based on the frequency band information and the received signal; and Demodulating means for loading software corresponding to a wireless communication system and demodulating a received signal using the software; Characterized in that it comprises.

  In the present invention, when the frequency resolution control means performs Fourier transform on a signal having a frequency bandwidth to be detected using the remaining resources of the computation resources of the signal processing device, the density of FFT points that can be processed is The number of FFT points is updated when the density of FFT points necessary for detecting each wireless communication method is higher than the density.

  In the present invention, the frequency resolution control means is configured so that, when a new wireless communication system is registered, the FFT point is based on whether the total bandwidth to be detected is expanded or the narrowest bandwidth is narrowed. It is determined whether or not it is necessary to increase the number, and when it is determined that the number of FFT points needs to be increased, the number of FFT points is set to be increased.

  In the present invention, the frequency band extracting unit includes a first Fourier transform unit that processes all of the frequency bandwidths to be extracted, and a second Fourier transform unit that processes only a predetermined frequency bandwidth, The frequency resolution control means can process the total number of FFT points used in each of the first Fourier transform means and the second Fourier transform means by using the remaining resources of the computation resources of the signal processing device. And the density of the number of FFT points of the second Fourier transform means is equal to the number of FFT points necessary for detecting a radio communication system signal in the frequency band processed by the second Fourier transform means. It is characterized by being set to be larger than the density.

  The present invention relates to a signal processing method in a signal processing apparatus that performs signal processing of received signals using a plurality of different wireless communication schemes, and is based on the calculation capability of the signal processing apparatus and a frequency bandwidth that is a target of signal detection. A frequency resolution control step for determining the number of FFT points of Fourier transform, and Fourier transforming the received signal based on the determined number of FFT points, extracting a frequency band in which the received power in the frequency domain is greater than a predetermined value, A frequency band extracting step for outputting the extracted information of the frequency band; a wireless communication method estimating step for estimating a wireless communication method used in the frequency band based on the frequency band information and the received signal; Load software corresponding to the estimated wireless communication method, and use the software And having a demodulation step of demodulating the signal signal.

  According to the present invention, when the frequency resolution control step performs Fourier transform on a signal having a frequency bandwidth that is a target of signal detection using the remaining resources of the computation resources of the signal processing device, the density of FFT points that can be processed is determined. The number of FFT points is updated when the density of FFT points necessary for detecting each wireless communication method is higher than the density.

  In the present invention, the frequency resolution control step may be performed based on whether the total bandwidth to be detected is expanded or the narrowest bandwidth is narrowed when a new wireless communication method is registered. It is determined whether or not it is necessary to increase the number, and when it is determined that the number of FFT points needs to be increased, the number of FFT points is set to be increased.

  In the present invention, the frequency band extraction step includes a first Fourier transform step for processing all of the frequency bandwidths to be extracted, and a second Fourier transform step for processing only a predetermined frequency bandwidth, The frequency resolution control step is an FFT in which the total number of FFT points used in each of the first Fourier transform step and the second Fourier transform step can be processed using the remaining resources of the computation resources of the signal processing device. The number of FFT points that is equal to or less than the number of points and that is necessary for detecting a signal of a wireless communication system in the frequency band processed by the second Fourier transform step in which the density of the FFT points in the second Fourier transform step is processed It is characterized in that it is set so as to be larger than the density.

  ADVANTAGE OF THE INVENTION According to this invention, while suppressing the increase in CPU processing load by FFT processing, the detection accuracy of a wireless communication system detection process can be improved, and the signal processing of wireless communication can be performed, and both processing load and detection accuracy are made compatible. The effect of being able to be obtained.

It is a block diagram which shows the structure of the 1st Embodiment of this invention. It is a flowchart which shows the processing operation of the apparatus shown in FIG. It is explanatory drawing which shows the relationship of the processing load for every CPU performance with respect to the number of FFT points used for control of frequency resolution. It is explanatory drawing which shows the relationship of the non-detection / false detection rate for every bandwidth with respect to the number of FFT points used for control of frequency resolution. It is a block diagram which shows the structure of the 2nd Embodiment of this invention.

<First Embodiment>
A signal processing apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment. The signal processing apparatus provided in the receiving apparatus includes a first delay unit 1, a second delay unit, a radio communication scheme estimation unit 3, an FFT unit 4, a signal detection unit 5, a radio communication scheme allocation unit 6, a demodulation unit 7, and software. A storage unit 8 is provided. The signal processing apparatus also includes a wireless communication system management unit 9, a signal processing device information management unit 10, a CPU load information management unit 11, a CPU load monitoring unit 12, and a frequency resolution control unit 13.

  The digital received signal is duplicated / branched into three and input to the first delay unit 1, the second delay unit 2 and the FFT unit 4, respectively. The signal input to the FFT unit 4 is converted from a time domain signal to a frequency domain signal. The signal in the frequency domain is determined by the signal detection unit 5 as to whether or not there is a frequency spectrum having a level equal to or higher than a threshold value. Input to the communication method estimation unit 3.

  The wireless communication scheme estimation unit 3 inputs the frequency information detected by the signal detection unit 5 and the reception signal delayed by the second delay unit 2. The reason why the delay processing is necessary is that the signal is input to the wireless communication scheme estimation unit 3 after waiting for a time corresponding to the processing in the signal detection unit 5. The wireless communication system estimation unit 3 performs further signal analysis on the detected frequency with respect to the reception signal delayed by the second delay unit 2, and estimates the wireless communication system. The signal analysis here is a pattern of a time-domain signal of a detected frequency band extracted with a BPF or the like and a preamble signal of each wireless communication method using the frequency band stored in advance. This is realized by specifying which wireless communication method is used by performing matching. Symbol rate analysis, phase deviation analysis, and the like may be applied as other signal analysis methods. Any one of these may be implemented, or may be implemented in combination.

  Information on the estimated wireless communication method is input to the wireless communication method allocating unit 6, the wireless signal processing software corresponding to this wireless communication method is searched from the software stored in the software storage unit 8, and the demodulation unit 7 is searched. To load. The software storage unit 8 stores information on the number of CPUs necessary for the processing of the radio signal processing software (that is, necessary CPU resources), and the radio communication system allocation unit 6 stores the information on the corresponding radio signal processing software. The allocation to the CPU is determined using the information on the necessary number of CPUs, the activation processing of the radio signal processing software loaded (registered) in the demodulation unit 7 is performed on the allocated CPU, and the first delay unit 1 Demodulation processing of the received signal delayed by.

  In this way, for the frequency specified based on the FFT processing, the wireless communication method is specified using the signal delayed by the second delay unit 2, and the corresponding software is loaded into the demodulator 7 to obtain the first delay. Information can be acquired from the signal included in the signal delayed by the unit 1.

  Here, the frequency resolution control unit 13 controls the number of FFT points using the CPU performance of the signal processing device, the bandwidth of the wireless communication system, and the CPU load information in order to achieve the target value of detection accuracy. Specifically, first, the number of FFT points is calculated from the CPU performance of the receiving apparatus with respect to the bandwidth of the wireless communication method to be detected. For example, in order to detect all of the plurality of wireless communication systems supported by the signal processing device, the total bandwidth required and the bandwidth of the wireless communication system with the narrowest bandwidth among the wireless communication systems are specified, Among the CPU resources of the receiving device, when the resource used for FFT processing is specified and the FFT processing is performed with the CPU resource for the specified bandwidth, the number of FFT points that can be processed is the initial number of FFT points. Become.

  Next, when a new wireless communication method is registered in the signal processing apparatus, information such as a use frequency and a bandwidth of the new wireless communication method is added to the wireless communication method management unit 9 as wireless communication method information. When the total bandwidth to be detected at this time is expanded, or the narrowest bandwidth is narrowed, and the CPU resource is further reduced, the number of FFT points needs to be reviewed. Therefore, the frequency resolution control unit 13 updates the number of FFT points based on the updated information (bandwidth, CPU load information). The bandwidth information of the wireless communication system is the wireless communication system manager 9, the CPU performance of the signal processor is the signal processor information manager 10, and the CPU load information is the CPU load information acquired by the CPU load monitor 12. Obtained from the CPU load information management unit 11 to be managed.

  Next, the processing operation of the signal processing apparatus shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a flowchart showing the processing operation of the signal processing apparatus shown in FIG. At the start of the operation of the signal processing device, the frequency resolution control unit 13 acquires the CPU performance information from the signal processing device information management unit 10 and the wireless communication system bandwidth information to be detected from the wireless system information management unit 9. Then, the number of FFT points is determined (step S1). The frequency resolution control unit 13 stores a table indicating the relationship between the CPU performance and the number of FFT points, and a table indicating the relationship between the bandwidth of the wireless communication method and the number of FFT points. With reference to this table, the FFT points are stored. Determine the number.

  FIG. 3 shows the relationship between the CPU performance and the number of FFT points. FIG. 3 is a diagram showing the relationship of the processing load for each CPU performance with respect to the number of FFT points used for controlling the frequency resolution. If the number of FFT points is increased, the processing load of the CPU increases, and the processing performance of the CPU is small, for example, the operation clock is slow. FIG. 4 shows the relationship between the bandwidth of the wireless communication system and the number of FFT points. FIG. 4 is a graph of the non-detection / false detection rate for each bandwidth with respect to the number of FFT points used for frequency resolution control. When the number of FFT points is lowered, the non-detection / false detection rate deteriorates, and for a wireless communication system with a narrow bandwidth, the specified value of the non-detection / false detection rate is exceeded with a larger number of FFT points.

  During operation of the signal processing device, the CPU load monitoring unit 12 monitors the CPU load at any time and manages the CPU load information management unit 11. The frequency resolution control unit 13 acquires CPU load information from the CPU load information management unit 11 and determines whether or not the CPU load exceeds a specified value (step S2). As a result of this determination, when the CPU load exceeds a specified value, such as by loading a new wireless communication method, the frequency resolution control unit 13 determines whether or not the number of FFT points can be reduced (step S3). If the number of FFT points cannot be lowered as a result of this determination, an alarm indicating that the CPU load is over is transmitted with the number of FFT points unchanged (step S4).

  On the other hand, when the number of FFT points is lowered due to the relationship between the bandwidth and detection accuracy of the existing wireless communication system, the frequency resolution control unit 13 performs a process of reducing the number of FFT points (step S5). That is, the number of FFT points and the detection accuracy (non-detection rate / false detection rate) shown in FIG. 4 for the narrowest bandwidth value among the wireless communication methods managed by the wireless communication method management unit 9. From the relationship, if the threshold of detection accuracy is not exceeded even if the number of FFT points is lowered, it is determined that the number of FFT points can be lowered.

  Next, when the CPU load does not exceed the specified value, the frequency resolution control unit 13 determines whether a new wireless communication method is registered in the wireless communication method management unit 9 (step S6). . As a result of this determination, when a new wireless communication system is registered, the frequency resolution control unit 13 increases the total bandwidth to be detected or narrows the narrowest bandwidth by the new wireless communication system. Since there is a possibility that the specified value of the detection accuracy cannot be satisfied, it is determined whether or not it is necessary to increase the number of FFT points (step S7). If it is necessary to increase the number of FFT points as a result of this determination, the frequency resolution control unit 13 performs a process of increasing the number of FFT points (step S8).

  On the other hand, if a new wireless communication method is not registered, or if the detection accuracy can be maintained without increasing the number of FFT points even if it is registered, the frequency resolution control unit 13 maintains the number of FFT points as it is ( Step S9; that is, no processing is performed). The frequency resolution control unit 13 repeatedly executes the processing operations of steps S2 to S9 shown in FIG.

  In this way, in the software defined radio receiving apparatus with limited CPU performance, the number of FFT points for frequency analysis is optimally controlled using CPU load information and information on the bandwidth of the wireless communication method to be detected. Thus, it is possible to improve the detection accuracy of the wireless communication method detection processing while taking into consideration the influence of the CPU processing load due to the FFT processing.

<Second Embodiment>
Next, a signal processing device according to a second embodiment of the present invention will be described. FIG. 5 is a block diagram showing the configuration of the embodiment. In this figure, the same parts as those in the apparatus shown in FIG. The apparatus shown in FIG. 5 is different from the apparatus shown in FIG. 1 in that instead of the FFT unit 4 and the signal detection unit 5, a first FFT unit 14, a first signal detection unit 15, a band limiting unit 16, a second FFT unit 17 and The second signal detection unit 18 is provided, and the frequency resolution control unit 13 is configured to control the two FFT units (the first FFT unit 14 and the second FFT unit 17).

  The signal processing apparatus shown in FIG. 5 responds by performing FFT in two stages when higher-speed wireless communication system detection processing is required or when high accuracy is required for a narrower-band wireless communication system. To do. For example, a case will be described in which a narrow bandwidth wireless communication method that requires high accuracy (that is, high density is required as the number of FFT points) is registered. The first FFT unit 14 performs signal detection for a wireless communication scheme that requires high-speed signal processing by reducing the number of FFT points for all bands.

  On the other hand, the second FFT unit 17 increases the density of FFT points with respect to the received signal whose band is limited by using a filter or the like in the band limiting unit 16 in order to process a wireless communication method that requires high accuracy. In this way, by making the two FFT units play different roles, the frequency resolution of some bandwidths is reduced without increasing the overall number of FFT points, and detection accuracy for a wireless communication system with a narrow bandwidth is detected. Improvement can be realized.

  The frequency resolution control unit 13 controls both the first FFT unit 14 and the second FFT unit 17, and the first FFT unit 14 corresponds to a radio communication scheme that requires high-speed processing, so that more FFT is performed. It is necessary to reduce the number of points. Instead, the second FFT unit 17 corresponds to a wireless communication method that cannot be detected by the first FFT unit 14 or whose use frequency or the like cannot be specified.

  As described above, the FFT processing is performed in two stages, the FFT processing is performed at a high speed by coarsening the frequency resolution, and the FFT processing is performed by increasing the detection accuracy by reducing the frequency resolution in a narrow band. It is possible to satisfy both the demand for the communication method detection processing and the maintenance of detection accuracy for a wireless communication method with a narrow bandwidth.

  A software defined radio receiver (flexible wireless system) detects a wireless communication method used by a wireless terminal and loads software corresponding to the detected wireless communication method to perform signal processing. Is detected in which frequency band the received power is detected from the signal in the frequency domain obtained by Fourier transforming the received signal. This narrows down the wireless communication system, but when performing a Fourier transform on a wideband signal, the total number of FFT points is limited by the computing power of the signal processing device.

  On the other hand, because the density of the number of FFT points required for detection (number of FFT points per unit bandwidth) differs for each wireless communication method to be detected, when the number of FFT points is small, the detection accuracy is low. is there. In the above-described signal processing device, the number of FFT points that can be processed is calculated based on its own calculation capability, and the density of FFT points is calculated based on the relationship between the number of FFT points and the total bandwidth that is the target of signal detection. When the density of the obtained FFT points is larger than the density of FFT points required for detection of each wireless communication system, the number of FFT points is updated. By adopting such a configuration, it is possible to avoid deterioration in signal detection accuracy.

  In addition, by using two types of FFT processing, one of them processes the entire band for signal detection, and the other processes a wireless communication method that requires a high FFT point density. Deterioration of signal detection can be avoided within the range of computing power. In this case, the number of FFT points necessary for the FFT means corresponding to the wireless communication system requiring high FFT point density is assigned first, and the remaining number of FFT points is assigned to the entire band.

  A program for realizing the function of the processing unit in FIG. 1 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed, thereby executing a wireless communication signal. Processing may be performed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

  As mentioned above, although embodiment of this invention has been described with reference to drawings, the said embodiment is only the illustration of this invention, and it is clear that this invention is not limited to the said embodiment. is there. Accordingly, additions, omissions, substitutions, and other modifications of components may be made without departing from the spirit and scope of the present invention.

  A software radio reception apparatus that receives a plurality of radio communication system signals superimposed on each other and performs demodulation processing of each radio communication system within the same device, and can detect the radio communication system from the received signal without demodulation. Applicable to essential applications.

  DESCRIPTION OF SYMBOLS 1 ... 1st delay part, 2 ... 2nd delay part, 3 ... Wireless communication system estimation part, 4 ... FFT part, 5 ... Signal detection part, 6 ... Wireless communication system Allocation unit, 7 ... demodulation unit, 8 ... software storage unit, 9 ... wireless communication system management unit, 10 ... signal processing device management unit, 11 ... CPU load information management unit, 12. ..CPU load monitoring unit, 13 ... frequency resolution control unit, 14 ... first FFT unit, 15 ... first signal detection unit, 16 ... band limiting unit, 17 ... second FFT unit, 18: Second signal detector

Claims (8)

A signal processing device that performs signal processing of received signals by a plurality of different wireless communication schemes,
Frequency resolution control means for determining the number of FFT points of the Fourier transform based on the calculation capability of the signal processing device and the frequency bandwidth to be subjected to signal detection;
A frequency band extracting means for performing Fourier transform on the received signal based on the determined number of FFT points, extracting a frequency band in which the received power in the frequency domain is greater than a predetermined value, and outputting the extracted information of the frequency band;
Radio communication scheme estimation means for estimating a radio communication scheme used in the frequency band based on the frequency band information and the received signal;
A signal processing apparatus comprising: demodulation means for loading software corresponding to the estimated wireless communication method and demodulating a received signal using the software. The frequency resolution control means includes
The density of FFT points that can be processed is necessary to detect each wireless communication method when the signal of the frequency bandwidth to be detected is Fourier-transformed using the remaining resources of the computation resources of the signal processing device. The signal processing apparatus according to claim 1, wherein the number of FFT points is updated when the density is higher than the number of FFT points. The frequency resolution control means includes
When a new wireless communication method is registered, it is determined whether the number of FFT points needs to be increased based on whether the entire bandwidth to be detected is expanded or the narrowest bandwidth is decreased. The signal processing device according to claim 1, wherein when it is determined that the number of FFT points needs to be increased, the number of FFT points is set to be large. The frequency band extracting unit includes a first Fourier transform unit that processes all of the frequency bandwidths to be extracted, and a second Fourier transform unit that processes only a predetermined frequency bandwidth,
The frequency resolution control means is an FFT that can process the total number of FFT points used in each of the first Fourier transform means and the second Fourier transform means by using the remaining resources of the computation resources of the signal processing device. The number of FFT points that is equal to or less than the number of points and that is necessary for detecting the signal of the radio communication system in the frequency band processed by the second Fourier transform unit, the density of the FFT points of the second Fourier transform unit The signal processing device according to claim 1, wherein the signal processing device is set so as to be larger than the density of the signal. A signal processing method in a signal processing apparatus that performs signal processing of received signals by a plurality of different wireless communication methods,
A frequency resolution control step for determining the number of FFT points of the Fourier transform based on the calculation capability of the signal processing device and the frequency bandwidth to be subjected to signal detection;
A frequency band extracting step of performing Fourier transform on the received signal based on the determined number of FFT points, extracting a frequency band in which the received power in the frequency domain is larger than a predetermined value, and outputting the extracted information of the frequency band;
A wireless communication method estimation step for estimating a wireless communication method used in the frequency band based on the frequency band information and the received signal;
A signal processing method comprising: a demodulation step of loading software corresponding to the estimated wireless communication method and demodulating a received signal using the software. The frequency resolution control step includes:
The density of FFT points that can be processed is necessary to detect each wireless communication method when the signal of the frequency bandwidth to be detected is Fourier-transformed using the remaining resources of the computation resources of the signal processing device. 6. The signal processing method according to claim 5, wherein the number of FFT points is updated when the density is higher than the number of FFT points. The frequency resolution control step includes:
When a new wireless communication method is registered, it is determined whether the number of FFT points needs to be increased based on whether the entire bandwidth to be detected is expanded or the narrowest bandwidth is decreased. 6. The signal processing method according to claim 5, wherein when it is determined that the number of FFT points needs to be increased, the number of FFT points is set to be large. The frequency band extracting step includes a first Fourier transform step for processing all of the frequency bandwidths to be extracted, and a second Fourier transform step for processing only a predetermined frequency bandwidth,
The frequency resolution control step is an FFT in which the total number of FFT points used in each of the first Fourier transform step and the second Fourier transform step can be processed using the remaining resources of the computation resources of the signal processing device. The number of FFT points that is equal to or less than the number of points and that is necessary for detecting a signal of a wireless communication system in the frequency band processed by the second Fourier transform step in which the density of the FFT points in the second Fourier transform step is processed 6. The signal processing method according to claim 5, wherein the signal processing method is set to be larger than the density of the signal.

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