JP5391426B2 - Wireless device and program for causing computer to execute the same - Google Patents

Description

  The present invention relates to a wireless device for determining a state of wireless communication and a program for causing a computer to execute the wireless device.

  A wireless LAN (Local Area Network) system based on the IEEE 802.11 standard is installed in many electronic devices such as a notebook PC (Personal Computer), a mobile terminal, a mobile phone, and a digital camera. Widely used for general purposes in a wide range of situations.

  However, as the wireless LAN system is used for various applications, it is increasingly important to ensure the stability of the wireless LAN system. In order to ensure and maintain the safety of the operation of the wireless LAN system, it is important to investigate the communication environment and to measure and analyze the communication state before and during the operation of the wireless LAN system.

  In addition, not only the operation of existing systems, but also the development and design of new wireless communication systems for improving frequency utilization efficiency in the ISM (Industrial Scientific Medical) band and the establishment of performance evaluation conditions for the systems. It is important to understand the behavior of existing wireless communication systems in the environment (Non-Patent Document 1).

  There are two main methods for checking the communication state of the wireless LAN in the actual environment. The first method uses a monitor mode that is mounted on a commercially available wireless LAN adapter for PC. When investigating the communication status in a wired LAN, a technique is used to acquire information on packets flowing through the network using network investigation tools such as tcpdump (Non-patent Document 2) and wireshark (Non-patent Document 3). This method can also be applied to a wireless LAN. That is, by preparing an appropriate wireless LAN adapter / device driver, the monitor mode of the wireless LAN interface can be used, and detailed information included in a wireless LAN MAC (Media Access Control) frame can be obtained. In this method, the components of the measurement system can be obtained at a low cost, and it is possible to obtain a large amount of information including the upper layer without taking time and effort.

  The second method uses a real-time spectrum analyzer and a data logger to measure and record a wireless RF signal at a sufficiently high sampling rate for analysis. With this method, once the sampling data is acquired, various information relating to communication can be acquired by performing appropriate post-processing on the data.

Taro Maruma, Hitoshi Yano, Seiji Tsukamoto, Masazumi Ueha, “Proposal of Dynamic Spectrum Access System for Highly Efficient Frequency Sharing in ISM Band,” Shingaku Techniques, SR2008-97, pp. 53-57, March 2009. TCPDUMP / LIBPCAP public repository http://www.tcpdump.org/ Wireshark http://www.wireshark.org/

  However, the first method described above has the following two problems. One problem is related to the detection of signal transmission facts. If the wireless LAN adapter fails to receive a frame due to an insufficient reception signal strength or an influence such as arrival of interference, the fact that reception has failed cannot be obtained from the wireless LAN adapter. This means that it is difficult to completely grasp the presence of a wireless LAN signal other than a frame normally received by the observation device.

  Another problem is that of time measurement accuracy. The information recorded by the network investigation tool includes the reception time (time stamp) of the captured wireless LAN frame, but actually the time stamp includes offsets caused by various processing delays. . That is, the accuracy of time recording is not sufficient, and it is difficult to observe events at short intervals such as, for example, SIFS.

  Also, simply performing a simple time-frequency analysis on wideband sampling data using the second method described above can solve many of the two problems in the first method described above.

  However, in the second method described above, in order to obtain upper layer information transmitted by each frame of the wireless LAN, it is more complicated to directly demodulate the wireless LAN frame from wideband sampling data. There is a problem that processing is necessary.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a wireless device capable of determining the state of wireless communication by a simple method.

  Another object of the present invention is to provide a program for causing a computer to determine the state of wireless communication by a simple method.

  According to this invention, the wireless device includes first and second measurement units, a calculation unit, and a determination unit. The first measurement unit measures the reception strength of a radio signal inside a certain bandwidth around the center frequency of any one frequency channel. The second measurement unit records the communication content (monitoring data) of the radio signal at the center frequency of one frequency channel. The calculation means calculates a signal transmission function indicating the presence / absence of signal transmission based on the monitoring data recorded by the second measurement unit, and starts a correlation function calculation of the correlation function between the calculated signal transmission function and the received intensity. The operation is performed while changing the start time of the signal transmission function. The detecting means detects a time difference when the correlation function calculated by the calculating means has a maximum value as a relative time difference. The judging means shifts either the reception strength or the signal transmission function by a relative time difference and superimposes the reception strength and the signal transmission function on each other, and based on the result of the superimposition, the communication state around the wireless device Determine.

  Preferably, the calculation means calculates a rectangular function including a signal transmission time and a signal length as a signal transmission function based on the monitoring data recorded by the second measurement unit.

  Preferably, the calculation means calculates an impulse train consisting only of the signal transmission time as a signal transmission function based on the monitoring data recorded by the second measurement unit.

  Preferably, the calculation means calculates an impulse train consisting only of the signal transmission time based on the monitoring data recorded by the second measuring unit as a signal transmission function, and uses the signal transmission function consisting of the calculated impulse sequence. A rectangular function comprising a signal transmission time and a signal length based on the recorded monitoring data when the first correlation function is calculated and a relative time difference is not detected based on the calculated first correlation function. And a second correlation function is calculated using a signal transmission function comprising the calculated rectangular function. When the maximum value of the first correlation function is equal to or greater than the threshold value, the detection unit detects a time difference when the maximum value is obtained as a relative time difference, and the maximum value of the first correlation function is smaller than the threshold value. When the relative time difference is detected based on the second correlation function. When the maximum value of the first correlation function is equal to or greater than the threshold value, the determination unit shifts either the received intensity or the impulse train by a relative time difference and superimposes the received intensity and the impulse train on each other. Based on the combined result, the communication state around the wireless device is determined, and when the maximum value of the first correlation function is smaller than the threshold value, either the reception strength or the rectangular function is shifted by the relative time difference and received. The strength and the rectangular function are overlapped with each other, and the communication state around the wireless device is determined based on the overlapped result.

  Further, according to the present invention, the program to be executed by the computer is based on the communication content (monitoring data) included in the radio signal recorded by the computing means at the center frequency of the frequency channel of any one center frequency. A first step of calculating a signal transmission function indicating the presence / absence of signal transmission, and a reception means of the radio signal measured at the center frequency of one frequency channel and the signal transmission calculated by the calculation means in the first step. A second step of calculating the correlation function with the function while changing the start time of the signal transmission function for starting the correlation function calculation, and the detection means when the correlation function calculated in the second step has a maximum value. A third step of detecting the time difference as a relative time difference, and the determination means compares one of the reception intensity and the signal transmission function. Only time difference shift to each other by superposing the reception strength and signal transmission function, based on the result obtained by the superimposed, to execute a fourth step of determining a communication state of the peripheral wireless device to the computer.

  Preferably, in the first step, the calculation means calculates a rectangular function including a signal transmission time and a signal length as a signal transmission function based on the recorded monitoring data.

  Preferably, in the first step, the computing means computes an impulse train consisting only of the signal transmission time based on the recorded monitoring data as a signal transmission function.

  Preferably, in the first step, the calculation means calculates an impulse train consisting only of the signal transmission time based on the recorded monitoring data as a signal transmission function, and uses the signal transmission function consisting of the calculated impulse sequence. A rectangular function comprising a signal transmission time and a signal length based on the recorded monitoring data when the first correlation function is calculated and a relative time difference is not detected based on the calculated first correlation function. And a second correlation function is calculated using a signal transmission function comprising the calculated rectangular function. In the third step, when the maximum value of the first correlation function is greater than or equal to the threshold value, the detection means detects the time difference when the maximum value is obtained as a relative time difference, and the maximum of the first correlation function When the value is smaller than the threshold value, the relative time difference is detected based on the second correlation function. In the fourth step, when the maximum value of the first correlation function is equal to or greater than the threshold value, the determination unit shifts either the reception intensity or the impulse train by the relative time difference to make the reception intensity and the impulse train mutually And determining the communication state around the wireless device based on the result of the superposition, and when the maximum value of the first correlation function is smaller than the threshold value, either the reception strength or the rectangular function is set as a relative time. The reception intensity and the rectangular function are superimposed on each other by shifting by the difference, and the communication state around the wireless device is determined based on the superimposed result.

  In the radio apparatus according to the embodiment of the present invention, the correlation function between the reception intensity and the signal transmission function is calculated, and the time displacement of the signal transmission function that starts the correlation function calculation when the calculated correlation function is maximized Minute is obtained as a relative time difference, and either the reception strength or the signal transmission function is shifted by the obtained relative time difference to superimpose the reception strength and the signal transmission function, and based on the superimposed result The state of wireless communication is determined. As a result, a matching portion between the reception strength and the signal transmission function is determined as a frame, and a portion other than the matching portion is determined as a portion where reception of the frame has failed or a portion where the frame has not been transmitted.

  Therefore, even when the reception intensity increases due to the influence of interference, it can be determined that reception of the frame has failed due to the influence of the interference if the reception intensity and the signal transmission function do not match at the portion where the intensity has increased. . That is, it is possible to obtain the fact that frame reception has failed.

  In addition, the time displacement of the signal transmission function that starts the correlation function calculation is obtained as a relative time difference, and either the reception intensity or the signal transmission function is shifted by the obtained relative time difference, so that the reception intensity and the signal transmission are shifted. Since the function is superimposed, even if the reception time of the received frame includes an offset due to various processing delays, it is possible to determine the state of wireless communication while avoiding the offset. That is, the conventional problem related to time measurement accuracy can be solved.

  Furthermore, since the state of wireless communication is determined based on the result of superimposing the reception intensity and the signal transmission function, it is not necessary to acquire broadband sampling data, and complicated processing is not necessary. Therefore, the state of wireless communication can be easily determined.

It is a block diagram of the radio | wireless apparatus by Embodiment 1 of this invention. It is a figure which shows the result of the time frequency analysis with respect to RF signal. It is a conceptual diagram of reception intensity. It is a conceptual diagram of a rectangle function. 4 is a conceptual diagram of a correlation function in Embodiment 1. FIG. It is a figure which shows the result of the superimposition of reception intensity and a rectangular function. 3 is a flowchart illustrating a method for determining the state of wireless communication in the first embodiment. It is the schematic of a personal computer. 6 is a configuration diagram of a radio apparatus according to Embodiment 2. FIG. It is a conceptual diagram of an impulse train. FIG. 6 is a conceptual diagram of a correlation function in the second embodiment. 10 is a flowchart illustrating a method for determining a state of wireless communication in the second embodiment. FIG. 6 is a configuration diagram of a radio apparatus according to a third embodiment. 10 is a flowchart illustrating a method for determining a state of wireless communication in the third embodiment.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a configuration diagram of a radio apparatus according to Embodiment 1 of the present invention. Referring to FIG. 1, radio apparatus 1 according to Embodiment 1 of the present invention includes antennas 1 and 2, a sampling data measurement unit 3, a monitoring data measurement unit 4, and a processing unit 5.

  The sampling data measurement unit 3 includes a down converter 31, an AD converter 32, a storage device 33, and a reception intensity calculation unit 34. The monitoring data measurement unit 4 includes a wireless LAN interface 41 and a storage device 42. The processing unit 5 includes a calculation unit 51, a detection unit 52, and a determination unit 53.

  In the sampling data measuring unit 3, the center frequency f0 of the frequency channel determined by the method described later is set in advance. Then, the sampling data measuring unit 3 receives a radio signal from the radio communication space via the antenna 1 and performs a Fourier transform on the received radio signal. Thereafter, the sampling data measuring unit 3 measures the reception intensity in a frequency band having a constant bandwidth centered on the center frequency f0 from the radio signal converted into data on time-frequency. Then, the sampling data measuring unit 3 stores the measured reception intensity and outputs the stored reception intensity to the calculation unit 51 and the determination unit 53.

  More specifically, the down-converter 31 receives a radio signal as an RF signal via the antenna 1 and converts the received RF signal to an intermediate frequency band that falls within the operation range of the AD converter 32. The intermediate frequency signal is output to the AD converter 32. The AD converter 32 receives the intermediate frequency signal from the down converter 31, converts the received intermediate frequency signal from an analog signal to a digital signal, and records the converted digital signal in the storage device 33 as a received signal. The storage device 33 stores the received signal from the AD converter 32. The storage device 33 outputs a reception signal to the reception intensity calculation unit 34 in response to a request from the reception intensity calculation unit 34. The reception intensity calculation means 34 receives a reception signal from the storage device 33 and performs a Fourier transform on the received reception signal. Then, the reception intensity calculation means 34 measures the reception intensity in the frequency band of a certain bandwidth centered on the center frequency f0 from the reception signal converted into the data on time-frequency, and the measured reception intensity. Is stored in the storage device 33. The storage device 33 outputs the reception intensity to the calculation unit 51 in response to a request from the calculation unit 51, and outputs the reception intensity to the determination unit 53 in response to a request from the determination unit 53.

  The monitoring data measuring unit 4 is also preset with the center frequency f0 of the frequency channel. Then, the monitoring data measuring unit 4 receives the communication content (monitoring data) included in the radio signal in the frequency channel of the center frequency f0 via the antenna 2, stores the received monitoring data, and stores the stored monitoring data Data is output to the calculation means 51 and the determination means 53.

  More specifically, the wireless LAN interface 41 receives monitoring data in the frequency channel having the center frequency f0 in the monitor mode via the antenna 2, and records the received monitoring data in the storage device 42. In this case, the wireless LAN interface 41 records the monitoring data in the storage device 42 with a recording time longer than the estimated maximum time deviation so as to include the recording time of the sampling data in the storage device 33. .

  The storage device 42 stores monitoring data from the wireless LAN interface 41. The storage device 42 outputs monitoring data to the computing means 51 in response to a request from the computing means 51, and outputs monitoring data to the judging means 53 in response to a request from the determining means 53.

  The processing unit 5 reads the reception intensity from the storage device 33 and reads the monitoring data from the storage device 42. Then, the processing unit 5 determines the state of wireless communication based on the read reception intensity and monitoring data.

  More specifically, the computing unit 51 reads the reception intensity from the storage device 33 and reads the monitoring data from the storage device 42. The monitoring data includes a reception time, a data rate, a frame size, and a preamble length.

  And the calculating means 51 produces the rectangular function which shows the presence or absence of signal transmission based on the reception time and frame size which are contained in monitoring data.

  Then, the computing means 51 computes the correlation function between the received intensity and the rectangular function while changing the start time of the signal transmission function for starting the correlation function computation, and sends the computed correlation function to the detecting means 52 by the method described later. Output.

  The detection unit 52 receives the correlation function from the calculation unit 51, and detects a time difference when the correlation function has a maximum value based on the received correlation function. Then, the detection means 52 outputs the detected time difference to the determination means 53 as a relative time difference between the reception time of the RF signal and the recording time of the monitoring data.

  The determination unit 53 receives the reception intensity from the storage device 33, receives monitoring data from the storage device 42, and receives a relative time difference from the detection unit 52. Then, the determination unit 53 creates a rectangular function indicating the presence / absence of signal transmission based on the reception time and the frame size included in the monitoring data.

  Then, the determination unit 53 shifts either the reception intensity or the rectangular function by the relative time difference and superimposes the reception intensity and the rectangular function. And the determination means 53 determines the state of the radio | wireless communication in radio | wireless communication space based on the result of the superimposition, and outputs the determination result.

  FIG. 2 is a diagram illustrating a result of time-frequency analysis for an RF signal. Referring to FIG. 2, when an RF signal received from the periphery of the wireless device is Fourier transformed, a timing chart of signal components at each frequency is obtained. In FIG. 2, the white part is the signal component.

  The center frequency of the frequency band from which the signal component is obtained is determined as the center frequency f0 of the frequency channel for recording sampling data and monitoring data. Then, the determined center frequency f0 is preset in the sampling data measuring unit 3 and the monitoring data measuring unit 4.

  When the frequency band from which the signal component is obtained is composed of a plurality of frequency bands, any one center frequency of the plurality of frequency bands is determined as the center frequency f0.

  FIG. 3 is a conceptual diagram of reception strength. FIG. 4 is a conceptual diagram of a rectangular function. Referring to FIG. 3, the reception strength is a timing chart of signal strength of a radio signal within a frequency band having a fixed bandwidth centered on center frequency f0.

  Referring to FIG. 4, each of calculation means 51 and determination means 53 creates a rectangular function indicating the presence / absence of signal transmission based on the reception time and frame size included in the monitoring data.

Here, it is assumed that the reception strength (see FIG. 3) is x (t) and the rectangular function (see FIG. 4) is p ₁ (t).

The rectangular function p ₁ (t) is expressed by the following equation.

The calculating means 51 calculates the correlation function R _cc1 (Δ) while changing the time difference Δ by substituting the received intensity x (t) and the rectangular function p ₁ (t) into the following equation.

  In Equation (2), T represents a time length that contributes to the calculation.

Actually, x (t) is replaced with finite-length time-series data x _j representing the estimated reception strength of a radio signal in a frequency band having a constant bandwidth centered on the center frequency f0 in the frequency channel to be observed, The correlation function R _1i is calculated by the following equation using the time series data x _j .

In Equation (3), N _s is the number of samples that contribute to the calculation in the time series data x _j , and δ _t is the time interval of the time series data.

When the correlation function R _1i has a sharp peak at i = k, k · δ _t is a relative time difference between the reception time of the RF signal and the recording time of the monitoring data.

FIG. 5 is a conceptual diagram of correlation function R _{1i in} the first embodiment. When calculating the correlation function _{R 1i} while changing the time difference i · [delta] _t, the correlation function _{R 1i} is, the reception intensity x (t) a rectangular function _p 1 (t) and a sharp peak in terms of best match (single peak With a peak). The time difference at which this sharp peak is obtained is the relative time difference between the received intensity x (t) and the rectangular function p ₁ (t).

Therefore, the detection means 52 detects a sharp peak based on the correlation function R _1i received from the calculation means 51, and determines the time difference when the detected sharp peak is obtained as the received intensity x (t) and the rectangular function p. Detected as a relative time difference from ₁ (t).

  FIG. 6 is a diagram illustrating a result of superimposing the received intensity and the rectangular function. The determination unit 53 shifts either the reception intensity or the rectangular function by the relative time difference received from the detection unit 52 and superimposes the reception intensity and the rectangular function. As a result, the overlay result shown in FIG. 6 is obtained.

  Then, the determination unit 53 determines the matching portions MH1 to MH8 in which the received intensity and the rectangular function match as a frame, and the portions other than the matching portions MH1 to MH8 are portions in which no frame is transmitted or frames in which reception has failed. Judge as.

  Therefore, if a frame has been transmitted, the transmitted frame can be determined.If the frame has not been transmitted, it can be determined that the frame has not been transmitted. It can be determined that reception has failed.

  Further, when the matched portions MH1 to MH8 are determined as transmitted frames, it can be determined whether or not the wireless communication is congested based on the mutual time intervals of the matched portions MH1 to MH8.

As described above, the processing unit 5 calculates the correlation function R _1i between the reception intensity and the rectangular function, and the reception time of the RF signal and the recording time of the monitoring data when the calculated correlation function R _1i is maximized. The relative time difference between the received signal strength and the rectangular function is shifted by the received relative time difference, and the received signal strength and the rectangular function are superimposed. Determine.

  As a result, the matching portions MH1 to MH8 between the reception intensity and the rectangular function are determined as frames, and the portions other than the matching portions MH1 to MH8 are determined to be portions that have failed to receive a frame or portions that have not been transmitted.

  Therefore, even if the reception strength increases due to the influence of interference, if there is no rectangular function that matches the reception strength fluctuation in the portion where the reception strength increases, it is determined that frame reception has failed due to the interference. it can. That is, it is possible to obtain the fact that frame reception has failed.

  Further, a relative time difference between the reception time of the RF signal and the recording time of the monitoring data is obtained, and either the reception intensity or the rectangular function is shifted by the obtained relative time difference to superimpose the reception intensity and the rectangular function. Therefore, even if the reception time of the received frame includes an offset due to various processing delays, the state of wireless communication can be determined while avoiding the offset. That is, the conventional problem related to time measurement accuracy can be solved.

  Furthermore, since the wireless communication state is determined based on the result of superimposing the received intensity and the rectangular function, it is not necessary to acquire broadband sampling data, and complicated processing is not necessary. Therefore, the state of wireless communication can be easily determined.

  FIG. 7 is a flowchart illustrating a method for determining the state of wireless communication in the first embodiment. Referring to FIG. 7, when a series of operations is started, the calculation means 51 of the processing unit 5 stores the reception intensity at the center frequency of the data obtained by time-frequency analysis of the sampling data of the radio signal in the storage device 33. (Step S1).

  And the calculating means 51 reads monitoring data from the memory | storage device 42, and produces | generates the rectangular function which shows the presence or absence of signal transmission based on the read monitoring data (step S2).

  Then, the calculating means 51 calculates the correlation function between the reception intensity and the rectangular function by the method described above while changing the start time of the signal transmission function for starting the correlation function calculation (step S3).

  The detection means 52 receives the correlation function from the calculation means 51 and detects the time difference between the reception time of the RF signal and the recording time of the monitoring data when the received correlation function is maximized as a relative time difference (step S4). ).

  Then, the determination unit 53 shifts one of the reception strength and the rectangular function by the relative time difference to superimpose the reception strength and the rectangular function, and determines the state of wireless communication based on the result of the superposition. (Step S5). As a result, the series of operations ends.

  The processing in the processing unit 5 is actually executed by a program.

  FIG. 8 is a schematic diagram of a personal computer. Referring to FIG. 8, personal computer 100 includes an input / output unit 110, a ROM (Read Only Memory) 120, a RAM (Randum Access Memory) 130, a CPU (Central Processing Unit) 140, and a bus BS. .

  The input / output unit 110, the ROM 120, the RAM 130, and the CPU 140 are connected to each other via the bus BS.

  The input / output unit 110 receives the reception strength from the storage device 33 and stores the received reception strength in the RAM 130 via the bus BS. The input / output unit 110 receives monitoring data from the storage device 42 and stores the received monitoring data in the RAM 130 via the bus BS. Further, the input / output unit 110 receives the state of wireless communication determined by the CPU 140 via the bus BS, and outputs the received state of wireless communication to the outside.

  The ROM 120 stores a program PROG1 having the flowchart shown in FIG. The RAM 130 is a work memory for the CPU 140.

  The CPU 140 reads the program PROG1 from the ROM 120 via the bus BS, executes the read program PROG1, and determines the state of wireless communication by the method described above. Then, CPU 140 outputs the determination result of the wireless communication state to input / output unit 110 via bus BS.

  In this case, the CPU 140 reads the monitoring data from the RAM 130, generates a rectangular function based on the read monitoring data (see step S2), and stores the generated rectangular function in the RAM 130.

  Then, the CPU 140 reads the received intensity from the RAM 130, calculates a correlation function between the read received intensity and the rectangular function (see step S3), and stores the calculated correlation function in the RAM 130.

  After that, the CPU 140 reads the correlation function from the RAM 130, detects the relative time difference when the read correlation function becomes maximum (see step S4), and stores the detected relative time difference in the RAM 130.

  Subsequently, the CPU 140 reads the reception intensity, the rectangular function, and the relative time difference from the RAM 130, and determines the state of wireless communication by the above-described method based on the read reception intensity, the rectangular function, and the relative time difference (step (See S5).

  As described above, the program PROG1 is a program for causing the CPU 140 (computer) to determine the state of the wireless communication.

  When determining the state of wireless communication by executing the flowchart shown in FIG. 7, the state of wireless communication can be determined stably even if the number of reception strengths is small. A large amount of calculation is required for calculating the correlation function.

  Therefore, the wireless communication state determination method shown in FIG. 7 is a method that can stably determine the wireless communication state with a small amount of data if a high-speed computing unit is installed. In this case, the storage area (RAM 130) that holds the reception intensity can be reduced.

[Embodiment 2]
FIG. 9 is a configuration diagram of a radio apparatus according to the second embodiment. Referring to FIG. 9, wireless device 10A according to Embodiment 2 is the same as wireless device 10 except that processing unit 5 of wireless device 10 shown in FIG. 1 is replaced with processing unit 5A.

  The processing unit 5A is the same as the processing unit 5 except that the calculation unit 51 of the processing unit 5 shown in FIG. 1 is replaced with the calculation unit 51A and the determination unit 53 is replaced with the determination unit 53A.

  The computing means 51A reads the monitoring data from the storage device 42, and generates an impulse train consisting only of the reception time included in the read monitoring data as indicating the presence or absence of signal transmission.

  Then, the calculation means 51A calculates a correlation function between the generated impulse train and the received intensity, and outputs the calculated correlation function to the detection means 52.

  The calculation means 51A performs the same function as the calculation means 51 in other respects.

  Similar to the calculation unit 51A, the determination unit 53A reads the monitoring data from the storage device 42, and generates an impulse train including only the reception time included in the read monitoring data as indicating the presence / absence of signal transmission. Then, the determination unit 53A shifts one of the reception intensity and the impulse train by a relative time difference to superimpose the reception intensity and the impulse train, and performs wireless communication by the above-described method based on the result of the superposition. The state of is determined.

  The determination unit 53A performs the same function as the determination unit 53.

  FIG. 10 is a conceptual diagram of an impulse train. Referring to FIG. 10, the impulse train represents each reception time by an impulse response.

Assuming that the impulse train (see FIG. 10) is p ₂ (t), the impulse train p ₂ (t) is expressed by the following equation.

In Equation (4), N _f is the number of impulses (the number of received frames) constituting the impulse train p ₂ (t), and δ (t) is a Dirac delta function.

The calculating means 51A calculates the correlation function R _cc2 (Δ) while changing the time difference Δ by substituting the received intensity x (t) and the impulse train p ₂ (t) into the following equation.

Correlation function R _cc2 (Δ) corresponds to a value obtained by shifting reception time t _pi of each frame on the monitoring data by Δ and adding reception intensity x (t _pi −Δ) at time t _pi −Δ. .

Therefore, if the time correction value Δ is an appropriate value, most of x (t _pi −Δ) is expected to indicate one point within the corresponding frame arrival period. As a result, the correlation function R _cc2 (Δ) has a maximum value in the vicinity of the appropriate time correction value Δ.

FIG. 11 is a conceptual diagram of correlation function R _cc2 (Δ) in the second embodiment. (A) of FIG. 11 shows the correlation function R _cc2 (Δ) when the sampling time is 1 second and the average number of impulses (average number of received frames) included in the sampling time is 191. FIG. 11 (b) Indicates a correlation function R _cc2 (Δ) when the sampling time is 10 seconds and the average number of impulses included in the sampling time is 1914.

When the average number of impulses is sufficiently large, the correlation function R _cc2 (Δ) has one peak (see (a) in FIG. 11). However, when the average number of impulses is small, the correlation function R _cc2 (Δ) does not have a peak (see (b) of FIG. 11).

Therefore, when the average number of impulses is sufficiently large, the time difference when the correlation function R _cc2 (Δ) becomes maximum can be detected as a relative time difference.

The detection unit 52 of the radio apparatus 10A detects a time difference when the correlation function R _cc2 (Δ) received from the calculation unit 51A becomes a maximum as a relative time difference, and outputs the detected relative time difference to the determination unit 53A. To do.

  The determination unit 53A receives the relative time difference from the detection unit 52, shifts either the reception intensity or the impulse train by the received relative time difference, superimposes the reception intensity and the impulse train, and the result of the superposition Based on the above, the wireless communication state is determined by the same method as the determination unit 53.

As described above, the processing unit 5A calculates the correlation function R _cc2 (Δ) between the received intensity and the impulse train, and the reception time of the RF signal when the calculated correlation function R _cc2 (Δ) is maximized. The relative time difference from the recording time of the monitoring data is obtained, and either the reception intensity or the impulse train is shifted by the obtained relative time difference to superimpose the reception intensity and the impulse train, and based on the result of the superposition. To determine the state of wireless communication.

  As a result, a matching portion between the received intensity and the impulse train is determined as a frame, and a portion other than the matching portion is determined as a portion where reception of the frame has failed or a portion where no frame is transmitted.

  Therefore, even if the reception strength increases due to the influence of interference, if there is no impulse train that matches the reception strength fluctuation in the vicinity where the reception strength increases, it is determined that frame reception has failed due to the interference. it can. That is, it is possible to obtain the fact that frame reception has failed.

  Further, a relative time difference between the reception time of the RF signal and the recording time of the monitoring data is obtained, and either the reception intensity or the impulse train is shifted by the obtained relative time difference to superimpose the reception intensity and the impulse train. Therefore, even if the reception time of the received frame includes an offset due to various processing delays, the state of wireless communication can be determined while avoiding the offset. That is, the conventional problem related to time measurement accuracy can be solved.

  Furthermore, since the wireless communication state is determined based on the result of superimposing the received intensity and the impulse train, it is not necessary to acquire broadband sampling data, and complicated processing is not necessary. Therefore, the state of wireless communication can be easily determined.

  FIG. 12 is a flowchart illustrating a method for determining the state of wireless communication according to the second embodiment. The flowchart shown in FIG. 12 is the same as the flowchart shown in FIG. 7 except that steps S2, S3, and S5 in the flowchart shown in FIG. 7 are replaced with steps S2A, S3A, and S5A, respectively.

  Referring to FIG. 12, when a series of operations is started, step S1 described above is executed. Then, the calculation unit 51A reads the monitoring data from the storage device 42, and generates an impulse train indicating the presence / absence of signal transmission based on the read monitoring data (step S2A).

  Thereafter, the calculating means 51A calculates the correlation function between the reception intensity and the impulse train while changing the start time of the signal transmission function for starting the correlation function calculation (step S3A).

  And step S4 mentioned above is performed.

  Thereafter, the determination unit 53A receives the reception intensity from the storage device 33, receives the monitoring data from the storage device 42, and receives the relative time difference from the detection unit 52. Then, the determination unit 53A generates an impulse train based on the received monitoring data. Thereafter, the determination unit 53A shifts one of the reception intensity and the impulse train by a relative time difference to superimpose the reception intensity and the impulse train, and determines the state of the wireless communication based on the result of the superposition. (Step S5A). As a result, a series of operations is completed.

  Also in the second embodiment, the determination of the state of wireless communication is executed by a program. In other words, the ROM 120 of the personal computer 100 stores the program PROG2 having the flowchart shown in FIG. Determine. Then, CPU 140 outputs the determination result of the wireless communication state to input / output unit 110 via bus BS.

  In this case, CPU 140 reads monitoring data from RAM 130, generates an impulse train based on the read monitoring data (see step S2A), and stores the generated impulse train in RAM 130.

  The CPU 140 reads the received intensity from the RAM 130, calculates a correlation function between the read received intensity and the impulse train (see step S3A), and stores the calculated correlation function in the RAM 130.

  After that, the CPU 140 reads the correlation function from the RAM 130, detects the relative time difference when the read correlation function becomes maximum (see step S4), and stores the detected relative time difference in the RAM 130.

  Subsequently, the CPU 140 reads the reception intensity, impulse train, and relative time difference from the RAM 130, and determines the state of wireless communication by the method described above based on the read reception intensity, impulse train, and relative time difference (step (See S5A).

  As described above, the program PROG2 is a program for causing the CPU 140 (computer) to determine the state of wireless communication.

  When the flowchart shown in FIG. 12 is executed to determine the state of wireless communication, the calculation amount per sampling data amount is reduced. That is, the calculation amount decreases at a ratio of [frame rate / sampling rate] to the sampling data amount. For example, when the reception strength of the received signal of the wireless LAN is acquired at an interval of 1 μsec and the frames of the wireless LAN arrive at an average interval of 100 μsec (100 times the sampling rate), the calculation amount is reduced to about 1/100 Can be reduced. The calculation does not necessarily require a high-speed computing unit.

On the other hand, the calculation of the correlation function R _cc2 (Δ) requires a large amount of data as described above.

  Therefore, if a large-capacity memory can be used, the computing unit may be low-speed, so the wireless communication state determination method according to the second embodiment is suitable.

  Others are the same as in the first embodiment.

[Embodiment 3]
FIG. 13 is a configuration diagram of a radio apparatus according to the third embodiment. Referring to FIG. 13, wireless device 10B according to Embodiment 3 is the same as wireless device 10 except that processing unit 5 of wireless device 10 shown in FIG. 1 is replaced with processing unit 5B.

  The processing unit 5B is obtained by replacing the calculation unit 51 of the processing unit 5 shown in FIG. 1 with the calculation unit 51B, replacing the detection unit 52 with the detection unit 52A, and replacing the determination unit 53 with the determination unit 53B. This is the same as the processing unit 5.

  The computing unit 51B reads the monitoring data from the storage device 42, and generates a rectangular function indicating the presence / absence of signal transmission based on the reception time and the frame size included in the read monitoring data. In addition, the calculation unit 51B reads the monitoring data from the storage device 42, and generates an impulse train including only the reception time included in the read monitoring data as indicating the presence / absence of signal transmission.

Then, the calculating means 51B calculates the correlation function R _cc2 (Δ) between the generated impulse train and the received intensity by the method described above, and outputs the calculated correlation function R _cc2 (Δ) to the detecting means 52A.

After that, when receiving the signal NPK indicating that the maximum value of the correlation function R _cc2 (Δ) is smaller than the threshold value, the calculation unit 51B calculates the correlation function R _1i between the received intensity and the rectangular function, and the calculated correlation. The function R _1i is output to the detection means 52A.

  In addition, the calculation means 51B performs the same function as the calculation means 51.

Upon receiving the correlation function R _cc2 (Δ) from the calculation unit 51B, the detection unit 52A detects the maximum value of the received correlation function R _cc2 (Δ). Then, the detection unit 52A holds a threshold value in advance, and determines whether or not the detected maximum value is equal to or greater than the threshold value.

  When the maximum value is greater than or equal to the threshold value, the detection unit 52A detects a time difference when the maximum value is obtained as a relative time difference, and outputs the detected relative time difference to the determination unit 53B.

On the other hand, when the maximum value is smaller than the threshold value, the detection unit 52A generates a signal NPK and outputs it to the calculation unit 51B and the determination unit 53B. The detection unit 52A, the correlation function receives the R _1i from computing means 51B, the correlation function the time difference when sharp peak of R _1i is obtained is detected as a relative time difference, the detected relative time difference determining means Output to 53B.

  The determination unit 53B reads the monitoring data from the storage device 42, and generates a rectangular function indicating the presence / absence of signal transmission based on the reception time and the frame size included in the read monitoring data. Further, the determination unit 53B reads the monitoring data from the storage device 42, and generates an impulse train including only the reception time included in the read monitoring data as indicating the presence / absence of signal transmission.

  When receiving the relative time difference from the detection unit 52A before receiving the signal NPK, the determination unit 53B shifts either the reception intensity or the impulse train by the received relative time difference and superimposes the reception intensity and the impulse train. In addition, based on the result of the superposition, the wireless communication state is determined by the same method as the determination unit 53.

  Further, when the determination unit 53B receives the signal NPK from the detection unit 52A and then receives the relative time difference from the detection unit 52A, the determination unit 53B shifts either the reception intensity or the rectangular function by the received relative time difference and receives it. The strength and the rectangular function are overlapped, and the state of wireless communication is determined by the same method as the determination unit 53 based on the overlap result.

  The determination unit 53B performs the same function as the determination unit 53 in addition.

  FIG. 14 is a flowchart illustrating a method for determining the state of wireless communication according to the third embodiment.

  Referring to FIG. 14, when a series of operations is started, calculation means 51B of processing unit 5B stores the received intensity at the center frequency of the data obtained by time-frequency analysis of sampling data of the radio signal in storage device 33. (Step S11).

  And the calculating means 51B reads monitoring data from the memory | storage device 42, and produces | generates the impulse sequence which shows the presence or absence of signal transmission based on the read monitoring data (step S12).

  Then, the calculation means 51B calculates the correlation function between the reception intensity and the impulse train by the above-described method while changing the start time of the signal transmission function for starting the correlation function calculation (step S13).

  Then, the calculating means 51B outputs the calculated correlation function to the detecting means 52A. The detection means 52A detects the maximum value of the correlation function (step S14), and determines whether or not the detected maximum value is greater than or equal to a threshold value (step S15).

  When it is determined in step S15 that the maximum value is equal to or greater than the threshold value, the detection unit 52A uses the time difference between the reception time of the RF signal and the recording time of the monitoring data as the relative time difference when the correlation function becomes maximum. It detects (step S16). Then, the detecting unit 52A outputs the detected relative time difference to the determining unit 53B.

  Determination means 53B receives the reception intensity from storage device 33, receives monitoring data from storage device 42, and receives a relative time difference from detection means 52A. Then, the determination unit 53B generates an impulse train based on the received monitoring data. Thereafter, the determination unit 53B shifts one of the reception intensity and the impulse train by a relative time difference to superimpose the reception intensity and the impulse train, and determines the state of the wireless communication based on the result of the superposition. (Step S17).

  On the other hand, when it is determined in step S15 that the maximum value is smaller than the threshold value, the detection unit 52A generates the signal NPK and outputs the generated signal NPK to the calculation unit 51B and the determination unit 53B.

  The computing unit 51B reads monitoring data from the storage device 42 in accordance with the signal NPK from the detecting unit 52A, and generates a rectangular function indicating the presence / absence of signal transmission based on the read monitoring data (step S18).

  Then, the calculation means 51B calculates a correlation function between the reception intensity and the rectangular function while changing the start time of the signal transmission function for starting the correlation function calculation (step S19), and outputs the calculated correlation function to the detection means 52A. To do.

  The detection unit 52A receives the correlation function from the calculation unit 51B, and detects the time difference between the reception time of the RF signal and the recording time of the monitoring data when the received correlation function is maximized as a relative time difference (step S20). ), And outputs the detected relative time difference to the determination means 53B.

  Thereafter, the determination unit 53B shifts one of the reception strength and the rectangular function by the relative time difference to superimpose the reception strength and the rectangular function, and determines the state of wireless communication based on the result of the superposition. (Step S21).

  And a series of operation | movement is complete | finished after step S17 or step S21.

  As described above, in the third embodiment, the state of wireless communication is determined by the method according to the second embodiment with a small amount of calculation (see “YES” in steps S11 to S14 and S15, S16 and S17), and the correlation function When the maximum value is smaller than the threshold value, the state of wireless communication is determined by the method according to the first embodiment (see “NO” in steps S11 to S14 and S15, S18 to S21).

  Thereby, even when the wireless communication state cannot be determined by the method according to the second embodiment with a small amount of calculation, the wireless communication state can be determined stably using the already acquired data.

  Also in the third embodiment, the determination of the state of wireless communication is executed by a program. That is, the ROM 120 of the personal computer 100 stores the program PROG3 having the flowchart shown in FIG. 14, and the CPU 140 reads out and executes the program PROG3 from the ROM 120 via the bus BS. Determine. Then, CPU 140 outputs the determination result of the wireless communication state to input / output unit 110 via bus BS.

  In this case, the CPU 140 reads the monitoring data from the RAM 130, generates an impulse train based on the read monitoring data (see step S12), and stores the generated impulse train in the RAM 130.

  Then, the CPU 140 reads the received intensity from the RAM 130, calculates a correlation function between the read received intensity and the impulse train (see step S13), and stores the calculated correlation function in the RAM 130.

  Thereafter, the CPU 140 reads the correlation function from the RAM 130, detects the maximum value of the read correlation function (see step S14), and determines whether or not the detected maximum value is equal to or greater than a threshold value (see step S15). .

  When the maximum value is equal to or greater than the threshold, the CPU 140 reads the correlation function from the RAM 130, detects the relative time difference when the read correlation function becomes the maximum (see step S16), and detects the detected relative time difference. Is stored in the RAM 130.

  Subsequently, the CPU 140 reads the reception intensity, impulse train, and relative time difference from the RAM 130, and determines the state of wireless communication by the method described above based on the read reception intensity, impulse train, and relative time difference (step (See S17).

  On the other hand, when the maximum value is smaller than the threshold value, the CPU 140 reads the monitoring data from the RAM 130, generates a rectangular function based on the read monitoring data (see step S18), and stores the generated rectangular function in the RAM 130. .

  Then, the CPU 140 reads the received intensity from the RAM 130, calculates a correlation function between the read received intensity and the rectangular function (see step S19), and stores the calculated correlation function in the RAM 130.

  After that, the CPU 140 reads the correlation function from the RAM 130, detects the relative time difference when the read correlation function becomes maximum (see step S20), and stores the detected relative time difference in the RAM 130.

  Subsequently, the CPU 140 reads the reception intensity, the rectangular function, and the relative time difference from the RAM 130, and determines the state of wireless communication by the above-described method based on the read reception intensity, the rectangular function, and the relative time difference (step (See S21).

  Thus, the program PROG3 is a program for causing the CPU 140 (computer) to execute the determination of the state of wireless communication.

  The rest is the same as in the first and second embodiments.

  In the above description, each of the wireless devices 10, 10A, 10B has been described as including one sampling data measuring unit 3 and one monitoring data measuring unit 4, but in the embodiment of the present invention, Not limited to this, each of the wireless devices 10, 10A, 10B may include the same number of sampling data measuring units 3 and monitoring data measuring units 4 as the number of center frequencies for which the state of wireless communication is determined.

  In this case, the number of each of the processing units 5, 5 </ b> A, 5 </ b> B may be one, or may be the same as the number of the sampling data measuring unit 3 and the monitoring data measuring unit 4. When the number of each of the processing units 5, 5A, 5B is one, each of the processing units 5, 5A, 5B determines the state of wireless communication by the above-described method at each of a plurality of center frequencies.

  In the above description, it has been described that each of wireless devices 10, 10A, 10B determines the state of wireless communication and outputs the determination result to the outside. However, the present invention is not limited to this. Each of radio apparatuses 10, 10A, and 10B may detect the relative time difference by the method described above and output the detected relative time difference to the outside. In this case, the relative time difference output to the outside is used for various types of control of wireless communication, such as synchronizing the timing of frame transmission / reception among a plurality of wireless devices.

  In the embodiment of the present invention, the rectangular function or the impulse train constitutes a “signal transmission function”.

In the embodiment of the present invention, the correlation function R _cc2 (Δ) constitutes a “first correlation function”, and the correlation function R _1i constitutes a “second correlation function”.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a wireless device that determines the state of wireless communication or a program that causes a computer to execute determination of the state of wireless communication.

  1, 2 antennas, 3 sampling data measurement unit, 4 monitoring data measurement unit, 5, 5A, 5B processing unit, 10, 10A, 10B wireless device, 31 down converter, 32 AD converter, 33, 42 storage device, 34 reception Intensity calculation means, 41 Wireless LAN interface, 51, 51A, 51B calculation means, 52, 52A detection means, 53, 53A, 53B determination means, 100 personal computer, 110 input / output unit, 120 ROM, 130 RAM, 140 CPU.

Claims (8)

A first measurement unit for measuring the reception strength of a radio signal at the center frequency of any one frequency channel;
A second measuring unit for recording communication contents included in a radio signal at a center frequency of the one frequency channel;
A signal transmission function indicating the presence or absence of signal transmission is calculated based on the communication content included in the recorded radio signal, and a correlation function between the calculated signal transmission function and the reception intensity is calculated as a correlation function of the signal transmission function. A computing means for computing while changing the start time of starting
Detecting means for detecting a time difference between the signal transmission function and the received intensity as a relative time difference when the correlation function calculated by the calculating means has a maximum value;
One of the reception strength and the signal transmission function is shifted by the relative time difference, and the reception strength and the signal transmission function are overlapped with each other, and a wireless communication state is determined based on the overlapped result. A wireless device comprising determination means for performing.   2. The radio according to claim 1, wherein the calculation unit calculates a rectangular function including a time of the signal transmission and a length of the signal as the signal transmission function based on communication contents included in the recorded radio signal. apparatus.   The radio apparatus according to claim 1, wherein the calculation unit calculates an impulse train including only the time of signal transmission as the signal transmission function based on communication contents included in the recorded radio signal. The computing means computes an impulse train consisting only of the signal transmission time as the signal transmission function based on the communication content included in the recorded wireless signal, and the signal transmission function comprising the computed impulse train is calculated. The first correlation function is used to calculate the signal transmission time based on the communication content included in the recorded radio signal when the relative time difference is not detected based on the calculated first correlation function. And calculating the second correlation function using the signal transmission function consisting of the calculated rectangular function,
The detection means detects the time difference when the maximum value is obtained when the maximum value of the first correlation function is greater than or equal to a threshold value as the relative time difference, and the maximum of the first correlation function Detecting a relative time difference based on the second correlation function when the value is less than a threshold;
When the maximum value of the first correlation function is equal to or greater than the threshold value, the determination unit shifts either the reception intensity or the impulse train by the relative time difference, and the reception intensity and the impulse train And the wireless communication state is determined based on the result of the superposition, and when the maximum value of the first correlation function is smaller than the threshold, either the reception strength or the rectangular function The radio apparatus according to claim 1, wherein the reception intensity and the rectangular function are superimposed on each other by shifting the relative time difference and the wireless communication state is determined based on the result of the superposition. A first step in which a computing means computes a signal transmission function indicating the presence or absence of signal transmission based on the communication content included in a radio signal recorded at the center frequency of any one frequency channel;
The calculating means starts calculating a correlation function of the signal transmission function using a correlation function between the reception strength of the radio signal measured at the center frequency of the one frequency channel and the signal transmission function calculated in the first step. A second step of calculating while changing the reference time to be
A third step of detecting, as a relative time difference, a time difference between the signal transmission function and the reception intensity when the correlation function calculated in the second step has a maximum value;
The determination means shifts either the reception strength or the signal transmission function by the relative time difference and superimposes the reception strength and the signal transmission function on each other, and based on the result of the superimposition, A program for causing a computer to execute a fourth step of determining a communication state.   In the first step, the calculation means calculates, as the signal transmission function, a rectangular function composed of the signal transmission time and the signal length based on the communication content included in the recorded wireless signal. The program according to claim 5.   The said calculating means calculates the impulse sequence which consists only of the time of the said signal transmission based on the communication content contained in the said radio | wireless signal in the said 1st step as the said signal transmission function. Program. In the first step, the calculation means calculates an impulse train consisting only of the signal transmission time as the signal transmission function based on the communication content included in the recorded radio signal, and the calculated impulse train When the first correlation function is calculated using the signal transmission function consisting of: and the relative time difference is not detected based on the calculated first correlation function, the communication content included in the recorded radio signal is A rectangular function composed of the signal transmission time and the signal length is calculated based on the signal transmission function comprising the calculated rectangular function, and a second correlation function is calculated;
In the third step, when the maximum value of the first correlation function is greater than or equal to a threshold value, the detection means detects the time difference when the maximum value is obtained as the relative time difference, When the maximum value of the first correlation function is smaller than the threshold, the relative time difference is detected based on the second correlation function;
In the fourth step, when the maximum value of the first correlation function is equal to or greater than the threshold, the determination unit shifts either the reception intensity or the impulse train by the relative time difference, and The reception strength and the impulse train are superimposed on each other, and based on the superimposed result, a wireless communication state is determined, and when the maximum value of the first correlation function is smaller than the threshold, the reception strength and The wireless communication state is determined based on a result of superimposing the reception intensity and the rectangular function on each other by shifting any one of the rectangular functions by the relative time difference, The listed program.

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