JP2023124488A - Communication quality estimation device, communication quality estimation method, and program - Google Patents

Abstract

To provide a communication quality estimation device that estimates communication quality more accurately in a shorter time in measuring communication quality.SOLUTION: Transmission of a beacon signal whose transmission is scheduled in advance between devices performing wireless communication is detected. The number of beacon signals detected per unit time is measured. Information about the quality of communication between the devices performing wireless communication is output based on the number of beacon signals detected per unit time.SELECTED DRAWING: Figure 1

Description

The present invention relates to a communication quality estimation device, a communication quality estimation method, and a program.

A Received Signal Strength Indicator (RSSI) value, which is an indicator of received signal strength, may be used to estimate the quality of communication with a wireless LAN master unit. For example, a user using a mobile terminal often selects an access point device displayed in descending order of RSSI values as a communication connection destination based on the RSSI values. Thus, the RSSI value is an index for confirming communication quality. Techniques for passively estimating communication quality are disclosed in Non-Patent Document 1 and Non-Patent Document 2.

Non-Patent Document 1 discloses a technique of passively estimating communication quality from the delay of a beacon signal periodically transmitted by a wireless LAN base station.

Non-Patent Document 2 discloses a technique of passively estimating communication quality from the retransmission rate of null frames transmitted by wireless LAN slave devices.

S. Vasudevan, 4 others, "Facilitating Access Point Selection in IEEE802.11 Wireless Networks", USENIX Association, "5th ACM SICGOMM Conference on Internet Measurement - IMC '05, Berkeley, California 2005", p.293-298 NAOKI ISHIKAWA, 2 others, "Nulls in the Air: Passive and Low-Complexity QoS Estimation Method for a Large-Scale Wi-Fi Network Based on Null Function Data Frames", "IEEE Access VOLUME7, 2019", February 2019 28th, p.28581-28591

In the measurement of communication quality as described above, it is desired to provide a technique for intercepting communication of a device that performs wireless communication and estimating communication quality in a short period of time and with high accuracy.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a communication quality estimation device, a communication quality estimation method, and a program that solve the above-described problems.

According to the first aspect of the present invention, a communication quality estimation device includes detection means for detecting transmission of a beacon signal whose transmission is pre-scheduled between devices that perform wireless communication, and detection of the beacon signal per unit time. and an output means for outputting information on communication quality between the devices performing wireless communication based on the number of beacon signals detected per unit time.

According to a second aspect of the present invention, a communication quality estimation method detects transmission of a beacon signal whose transmission is pre-scheduled between devices that perform wireless communication, and measures the number of detections of the beacon signal per unit time. Then, based on the number of detected beacon signals per unit time, information on communication quality between the devices performing wireless communication is output.

According to a third aspect of the present invention, a program comprises a computer of a communication quality estimation device, detection means for detecting transmission of a beacon signal whose transmission is pre-scheduled between devices that perform wireless communication, a unit of the beacon signal, It functions as a measuring means for measuring the number of detections per unit time and an output means for outputting information on the communication quality between the devices performing wireless communication based on the number of detections of the beacon signal per unit time.

According to the present invention, it is possible to intercept the communication of a device that performs wireless communication and estimate the communication quality of the communication with the device that performs wireless communication in a short period of time and with high accuracy.

1 is a block diagram showing the configuration of a communication system having the functions of a communication quality estimation device according to this embodiment; FIG. 3 is a hardware configuration diagram of a terminal device according to the embodiment; FIG. It is a figure which shows the functional block of the terminal device by 1st embodiment. It is a figure which shows the processing flow of the terminal device by 1st embodiment. FIG. 4 is a first diagram showing an example of output information from an output unit according to the embodiment; FIG. 10 is a second diagram showing an example of output information of the output unit according to the embodiment; FIG. 13 is a third diagram showing an example of output information of the output unit according to the embodiment; FIG. 14 is a fourth diagram showing an example of output information from the output unit according to the embodiment; FIG. 4 is a first diagram showing an example of experimental results by the communication system according to the present embodiment; FIG. 10 is a first diagram showing an example of experimental results by another communication system; FIG. 11 is a second diagram showing an example of experimental results by another communication system; FIG. 10 is a diagram showing the relationship between the measurement result, the correlation coefficient of the effective throughput, and the measurement time _T0 in each experimental result of communication quality; It is a functional block diagram of an AP device according to a second embodiment. It is a figure which shows the processing flow of the AP apparatus 2 by 2nd embodiment. FIG. 10 is a diagram showing the first embodiment in a state where communication load is applied; FIG. 4 is a diagram showing the relationship between the communication quality measurement time _T0 in the first embodiment and the correlation coefficient between each measurement result in different communication quality measurement modes and the effective throughput of data download. FIG. 10 is a diagram showing the second embodiment in a state where communication load is applied; FIG. 10 is a diagram showing the relationship between each measurement result in different communication quality measurement modes, the correlation coefficient between the effective throughput of data download, and the communication quality measurement time _T0 in the second embodiment; FIG. 10 is a diagram showing the second embodiment in a state where communication load is applied; FIG. 10 is a diagram showing the relationship between each measurement result in different communication quality measurement modes, the correlation coefficient between the effective throughput of data download, and the communication quality measurement time _T0 in the third embodiment; FIG. 10 is a diagram showing the relationship between each measurement result in different communication quality measurement modes, the correlation coefficient of the effective throughput of data upload, and the communication quality measurement time _T0 in the third embodiment; It is a figure which shows the minimum structure of a communication quality estimation apparatus. FIG. 4 is a diagram showing a processing flow in a communication quality estimation device with a minimum configuration;

A communication quality estimation device according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of a communication system 100 having the functions of a communication quality estimation device 10 according to the same embodiment. As shown in FIG. 1, the communication system is configured by wireless communication connection between a terminal device 1 and an access point device 2 (hereinafter referred to as an AP device 2). The AP device 2 establishes a wireless communication connection with the terminal device 1 using Wi-Fi (registered trademark) corresponding to the wireless LAN standard (IEEE802.11). The AP device 2 relays information transmitted from the terminal device 1 to another communication device. The AP device 2 also relays information transmitted from another communication device to the terminal device 1 . Wi-Fi (registered trademark) stipulates that the AP device 2 schedules and transmits a beacon signal every 0.1024 seconds. The terminal device 1 receives the beacon signal. The terminal device 1 has the function of the communication quality estimation device 10 . The terminal device 1 may be a smart phone, a tablet terminal, a personal computer, a server device, or the like.

Note that in the present embodiment, the AP device 2 establishes a wireless communication connection with the terminal device 1 using Wi-Fi (registered trademark) compliant with the wireless LAN standard (IEEE802.11). may establish a wireless communication connection with the terminal device 1 using another communication standard for transmitting beacon signals. Alternatively, the AP device 2 may transmit a regularly scheduled transmission signal similar to the beacon signal. In this case, the terminal device 1 may passively intercept a signal that is periodically scheduled to be transmitted from the AP device 2, handle the signal in the same manner as a beacon signal, and perform the following processing.

FIG. 2 is a hardware configuration diagram of the terminal device.
As shown in FIG. 2, the terminal device 1 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, an HDD (Hard Disk Drive) 104, a communication module 105, and a storage device 106. It is a computer provided with each hardware such as. Note that the AP device 2 may also have similar hardware.

<First Embodiment>
FIG. 3 is a diagram showing functional blocks of the terminal device according to the first embodiment.
As shown in FIG. 3, the terminal device 1 (communication quality estimation device 10) executes a pre-stored communication quality estimation program. Thereby, the terminal device 1 exhibits each function of the receiving section 11 , the measuring section 12 , the measurement time determining section 13 and the output section 14 .

The receiving unit 11 detects transmission of a beacon signal whose transmission is scheduled in advance between the terminal device 1 and the AP device 2 that perform wireless communication.
The measurement unit 12 measures the number of beacon signals detected per unit time.
The measurement time determination unit 13 determines the measurement time according to the usage status of the communication device.
The output unit 14 outputs information about communication quality between the terminal device 1 and the AP device 2 based on the number of beacon signals detected per unit time.

Thus, the terminal device 1 having the function of the communication quality estimation device 10 outputs the number of receptions of the beacon signal per unit time as the communication quality. Through such processing, the terminal device 1 estimates the communication quality with higher accuracy in a shorter time in measuring the communication quality with the AP device 2 .

FIG. 4 is a diagram showing the processing flow of the terminal device according to the first embodiment.
Next, the processing flow of the terminal device 1 will be described step by step.
The terminal device 1 that has entered the range of the radio signal transmitted by the AP device 2 detects that it has entered the communication range for communication with the AP device 2 (step S101). A well-known technique may be used for the detection of entering into the communication range. As an example, the receiving unit 11 of the terminal device 1 may detect, when the RSSI value is equal to or greater than a threshold, that the terminal device 1 has entered the communication range of the AP device 2 performing wireless communication whose RSSI value is equal to or greater than the threshold. The receiving unit 11 of the terminal device 1 may detect that it has entered the communication range of the AP device 2 by other processing.

When detecting that the terminal device 1 has entered the communication range of the AP device 2, the terminal device 1 detects reception of a beacon signal transmitted from the AP device 2 (step S102). For the beacon signal, for example, information indicating the type of beacon signal is recorded as information in a predetermined data area in the data frame of the beacon signal. Upon detecting reception of the beacon signal, the reception unit 11 outputs to the measurement unit 12 that the beacon signal has been received.

The measurement unit 12 counts the number n of times the beacon signal is received during the measurement time _T0 determined by the measurement time determination unit 13 (step S103). The measurement time T ₀ determined by the measurement time determination unit 13 may be a time recorded in the terminal device 1 in advance, or may be information included in some signal transmitted from the AP device 2 . Alternatively, it may be time information estimated by the terminal device 1 from the RSSI value or other information. When the measurement time _T0 is fixed, the terminal device 1 does not need to have the function of the measurement time determination unit 23 . The measurement unit 12 calculates the number of beacon signal receptions per unit time Cb by dividing the number of beacon signal receptions n during the measurement time T0 by the measurement time using equation ( ₁ ). (Step S104). The measurement unit 12 outputs the number of beacon signal receptions Cb per unit time to the output unit 14 .

FIG. 5 is a first diagram showing an example of output information of the output unit according to this embodiment.
FIG. 6 is a second diagram showing an example of output information from the output unit according to this embodiment.
FIG. 7 is a third diagram showing an example of output information from the output unit according to this embodiment.
FIG. 8 is a fourth diagram showing an example of output information from the output unit according to this embodiment.
The output unit 14 outputs the number of receptions Cb of the beacon signal per unit time as information on the quality of communication with the AP device 2 (step S105). For example, the output unit 14 outputs the number of receptions Cb of the beacon signal per unit time on the display of the terminal device 1 next to the icon a indicating whether the communication with the AP device 2 is good or bad (see FIG. 5). ). The output unit 14 may simply output the reception count Cb of the beacon signal per unit time to the display of the terminal device 1 as information indicating whether the communication with the AP device 2 is good or bad (Fig. 6). A user using the terminal device 1 determines that the quality of communication with the AP device 2 is better as the number of receptions Cb of the beacon signal per unit time is greater.

When the output unit 14 of the terminal device 1 detects that a plurality of AP devices 2 are present within a range of several meters to several tens of meters in the vicinity, and detects that the plurality of AP devices 2 are within the communication range, The number of receptions Cb per unit time is calculated as information indicating the communication status of all AP devices 2 within the communication range. The output unit 14 may display, for each AP device 2, the number of receptions Cb of the beacon signal transmitted by each AP device 2 per unit time in association with the identifier such as the name of the AP device.

Alternatively, the output unit 14 may convert the number of times the beacon signal is received per unit time into a scale of the amount of data transmission and output it. For example, the output unit 14 multiplies the number of receptions of the beacon signal per unit time by a coefficient for conversion to the scale of the data transmission amount per unit time, and converts it into information according to the scale of the data transmission amount. More specifically, the output unit 14 multiplies the received Cb of the beacon signal per unit time by the scale conversion coefficient K, and converts it into a data transmission amount per unit time (0 mbps to 10 mbps/0 mbps to 100 mbps, etc.). Then, the amount of data transmission per unit time may be output as information on communication quality. In this case as well, the output unit 14 displays the data transmitted as information about the communication quality next to the identifier such as the name of the AP device 2 displayed on the display and the icon indicating whether the communication with the AP device 2 is good or bad. You may make it output a quantity (refer FIG. 7). Also, the output unit 14 may display the amount of data transmission per unit time using an indicator (see FIG. 8).

FIG. 9 is a first diagram showing an example of experimental results of the communication system.
FIG. 9 shows, for example, the measurement result of the beacon signal reception count per unit time Cb (Beacon count [/s]) corresponding to the measurement time T ₀ in the terminal device 1, and the effective throughput (unit The data obtained by measuring the relationship with the transmission amount per hour (effective throughput [byte/s]) is shown. As for the effective throughput of the AP device 2, 0.0 on the vertical axis of the graph in FIG. 9 indicates 0 mbps, and 1.0 indicates 10 mbps. By changing the measurement time from 0.1 seconds to 0.9 seconds and from 1 second to 10 seconds, the number of receptions Cb of the beacon signal per unit time and the effective throughput (transmission amount per unit time) in the AP device 2 at that time ) was experimentally measured, and as shown in FIG. was 0.005 or less, and a significant numerical value was obtained for the correlation.

FIG. 10 is a first diagram showing an example of experimental results with another communication system.
FIG. 10 shows the relationship between the measurement result of the average beacon signal transmission interval and the effective throughput (transmission amount per unit time; effective throughput [byte/s]) in the AP device 2 in relation to the technology of Non-Patent Document 1. This is the data when measured by experiment. As for the effective throughput in the AP device 2, 0.0 on the vertical axis in the graph of FIG. 10 indicates 0 mbps, and 1.0 indicates 10 mbps. By changing the measurement time from 0.1 to 0.9 seconds and from 1 to 10 seconds, the relationship between the average beacon signal transmission interval and the effective throughput (transmission amount per unit time) in the AP device 2 was experimentally investigated. As a result of measurement, as shown in FIG. 10, the correlation coefficient between the average beacon signal transmission interval and the effective throughput in the AP device 2 at that time was −0.839, and the p-value was 0.005 or less. That is, the correlation between the beacon signal reception count per unit time Cb corresponding to the measurement time T0 shown in FIG. ₉ and the effective throughput (transmission amount per unit time) in the AP device 2 at that time is more significant. I understand.

FIG. 11 is a second diagram showing an example of experimental results with another communication system.
FIG. 10 shows the measurement result of the retransmission rate (NFDF retry rate) of the null frame (NFDF; Null Function Data frame) transmitted by the wireless LAN slave device in relation to the technology of Non-Patent Document 2, and the effective throughput in the AP device 2 (Transmission amount per unit time; Effective throughput [byte/s]) is measured experimentally. As for the effective throughput in the AP device 2, 0.0 on the vertical axis in the graph of FIG. 11 indicates 0 mbps, and 1.0 indicates 10 mbps. By changing the measurement time from 0.1 to 0.9 seconds and from 1 to 10 seconds, the relationship between the average beacon signal transmission interval and the effective throughput (transmission amount per unit time) in the AP device 2 was experimentally investigated. As a result of measurement, as shown in FIG. 11, the correlation coefficient between the null frame (NFDF) retransmission rate and the effective throughput in the AP device 2 at that time was -0.136, and the p-value was 0.020. That is, the correlation between the beacon signal reception count per unit time Cb corresponding to the measurement time T0 shown in FIG. ₉ and the effective throughput (transmission amount per unit time) in the AP device 2 at that time is more significant. I understand.

FIG. 12 is a diagram showing the relationship between the measurement result, the correlation coefficient of the effective throughput, and the communication quality measurement time _T0 in each experimental result.
Based on the experimental results shown in FIGS. 9, 10, and 11, the correlation coefficient between the measurement result and the effective throughput in each experimental result and the measurement time T ₀ (measurement intervals [s] ).

A solid line (Beacon count) indicates the relationship between the measurement result (the number of beacon signal receptions per unit time Cb), the correlation coefficient of the effective throughput, and the measurement time _T0 based on the experimental results shown in FIG. A dotted line (Beacon interval) indicates the relationship between the measurement result (average beacon signal transmission interval), the correlation coefficient of the effective throughput, and the measurement time _T0 based on the experimental results shown in FIG. A one-dot chain line (NFDF retry rate) indicates the relationship between the measurement result (null frame (NFDF) retry rate), the correlation coefficient of the effective throughput, and the measurement time _T0 based on the experimental results shown in FIG. The number of receptions Cb (Beacon count [/s]) of the beacon signal per unit time according to the measurement time _T0 , and the effective throughput in the AP device 2 at that time (transmission amount per unit time; Effective throughput [byte/s] ⁾ is based on experimentally measured data (results in Fig. 9). The number of receptions per hour Cb) can be obtained.

That is, the terminal device 1 having the function of the communication quality estimation device 10 according to the present embodiment can detect communication quality with higher accuracy in a shorter time.

Further, according to the terminal device 1 having the function of the communication quality estimation device 10 according to the present embodiment, the communication quality in wireless communication with the AP device 2 can be detected without imposing a load such as data transmission on the wireless communication. be able to.

Further, according to the terminal device 1 having the function of the communication quality estimation device 10 according to the present embodiment, even if the channel used in the access point device is automatically changed unintentionally, the beacon signal per unit time Deterioration of communication quality can be immediately detected based on the number of receptions of .

<Second embodiment>
FIG. 13 is a functional block diagram of the AP device according to the second embodiment.
In the first embodiment, an example in which the terminal device 1 has the function of the communication quality estimation device 10 is shown. However, the AP device 2 may have the function of the communication quality estimation device 10 .

As shown in FIG. 13, the AP device 2 according to the second embodiment executes a pre-stored communication quality estimation program. As a result, the AP device 2 has the functions of a measurement unit 22, a measurement time determination unit 23, and an output unit 24 as communication quality estimation functions in addition to the function of the access point function unit 21 (hereinafter referred to as the AP function unit 21). function.

The AP function unit 21 detects transmission of a beacon signal to the terminal device 1, which is the communication device of the communication connection destination.
The measurement unit 22 measures the number of receptions of beacon signals per unit time. The measurement unit 22 calculates the number of beacon signal receptions per unit time by dividing the number of beacon signal receptions per unit time by the beacon signal measurement time of the number of receptions.
The measurement time determining unit 23 determines the measurement time according to the usage status of the communication device.
The output unit 24 outputs information about the communication quality of its own device (AP device 2) based on the number of beacon signal receptions per unit time.

The AP device 2 having the function of the communication quality estimation device 10 in this way outputs the number of beacon signal transmissions per unit time as communication quality. Through such processing, the AP device 2 estimates the communication quality of its own wireless communication with another device in a shorter time and more accurately in measuring the communication quality of its own device.

FIG. 14 is a diagram showing the processing flow of the AP device 2 according to the second embodiment.
Next, the processing flow of the AP device 2 will be explained step by step.
The AP function unit 21 of the AP device 2 detects transmission of a beacon signal in its own device (step S201). Upon detecting transmission of the beacon signal, the AP function unit 21 outputs to the measurement unit 22 that the beacon signal has been transmitted.

The measurement unit 22 counts the number of transmissions n of the beacon signal transmitted by the device during the measurement time _T0 determined by the measurement time determination unit 13 (step S202). Note that the measurement time _T0 determined by the measurement time determination unit 13 may be a time recorded in the AP device 2 in advance, or may be a signal transmitted from the terminal device 1, other measurement devices, a server device, or the like. It may be information that is included. Alternatively, time information estimated from the RSSI value or other information by the terminal device 1 may be information received from the terminal device 1, other measuring devices, or a server device. Note that when the measurement time _T0 is fixed, the AP device 2 may not have the function of the measurement time determination unit 23 . The measurement unit 22 calculates the number of beacon signal transmissions _Cb2 per unit time by dividing the number of beacon signal transmissions n during the measurement time T0 by the measurement time using equation ( ₂ ). (step S203). The measurement unit 22 outputs to the output unit ₂₄ the number of beacon signal transmissions per unit time Cb2.

The output unit 24 outputs the number of beacon signal transmissions _Cb2 per unit time as information on the current communication quality of its own device (step S204). For example, the output unit 14 may transmit to a display unit such as a display provided in its own device, the terminal device 1, a measuring device, a server device, and the like. When outputting information about communication quality to the display of the AP device 2, the output unit 24 of the AP device 2 displays an icon indicating whether the communication state with the terminal device 1 or the like accessing the other device is good or bad. Horizontally, the number of beacon signal transmissions _Cb2 per unit time may be output. The output unit 24 may simply output the transmission frequency _Cb2 of the beacon signal per unit time to the display of its own device as information indicating whether the communication with the terminal device 1 or the like is good or bad. A user who checks the AP device 2 judges that the communication quality with the AP device ₂ is better as the number of beacon signal transmissions Cb2 per unit time increases.

Alternatively, the output unit 24 may convert the number of transmissions _Cb2 of the beacon signal per unit time into a data transmission amount scale and output it. For example, the output unit 24 multiplies the number of beacon signal transmissions per unit time by a coefficient for converting the scale of the data transmission amount per unit time, and converts it into information according to the scale of the data transmission amount. More specifically, the output unit 24 multiplies the number of beacon signal transmissions per unit time Cb ₂ by a scale conversion coefficient K to obtain a data transmission amount per unit time (0 mbps to 10 mbps/0 mbps to 100 mbps, etc.). After conversion, the amount of data transmission per unit time may be output as information on communication quality. In this case as well, the output unit 24 may output the data transmission amount as information on the communication quality next to the icon indicating the communication state of good or bad communication. The mode of outputting the information on the communication quality may be the same as the mode described in FIGS. 5 to 8 in the first embodiment.

<First embodiment>
FIG. 15 is a diagram showing the first embodiment in a state where a communication load is applied.
In the example of FIG. 15, the communication system 100 includes an AP device 2, a terminal device 1 wirelessly connected to the AP device 2, a communication terminal device 3, a load data receiving device 4, a load data transmitting device 5, and an observation device 6. is connected to the AP device 2 by wireless communication. In this state, in the first embodiment, the load data receiving device 4 downloads a large amount of data per unit time, imposing a download load on the AP device 2 . It is assumed that the two communication terminal devices 3 communicate with an external communication device using the AP device 2 as a gateway through the AP device 2 . In this state, the terminal device 1 wirelessly connects with the AP device 2 and estimates the communication quality of data download with the AP device 2 . Alternatively, the observation device 6 may function as the communication quality estimation device 10 , connect to the AP device 2 for wireless communication, and estimate the communication quality of data download with the AP device 2 .

FIG. 16 is a diagram showing the relationship between the communication quality measurement time _T0 in the first embodiment and the correlation coefficient between each measurement result and the effective throughput of data download in different communication quality measurement modes.
The solid line (Beacon count) shows the relationship between the measurement result (number of beacon signal receptions per unit time Cb), the correlation coefficient of the effective throughput of data download, and the measurement time _T0 in the load state of the system shown in FIG. indicates
A dotted line (Beacon interval) indicates the relationship between the measurement result (average beacon signal transmission interval), the correlation coefficient of the effective throughput of data download, and the measurement time _T0 in the load state of the system shown in FIG.
The one-dot chain line (NFDF retry rate) is the relationship between the measurement result (null frame (NFDF) retransmission rate), the correlation coefficient of the effective throughput of data download, and the measurement time _T0 in the load state of the system shown in FIG. indicates

In the first embodiment, the load data receiving device 4 downloads a large amount of data per unit time, and the download load is applied to the AP device 2 . Even in such a state, the number of receptions Cb (Beacon count [/s]) of the beacon signal per unit time according to the measurement time _T0 and the effective throughput (transmission amount per unit time; Effective throughput [byte/s]) is highly correlated, and it can be seen that communication quality can be detected with better accuracy in a shorter time.

<Second embodiment>
FIG. 17 is a diagram showing the second embodiment in a state where a communication load is applied.
In the example of FIG. 17, the communication system 100 includes an AP device 2, a terminal device 1 wirelessly connected to the AP device 2, a communication terminal device 3, a load data receiving device 4, a load data transmitting device 5, and an observation device 6. is connected to the AP device 2 by wireless communication. In this state, in the first embodiment, the load data transmission device 5 uploads a large amount of data per unit time to impose an upload load on the AP device 2 . It is assumed that the two communication terminal devices 3 communicate with an external communication device using the AP device 2 as a gateway through the AP device 2 . In this state, the terminal device 1 wirelessly connects with the AP device 2 and estimates the communication quality of data upload with the AP device 2 . Alternatively, the observation device 6 may function as the communication quality estimation device 10 , connect to the AP device 2 for wireless communication, and estimate the communication quality of data upload with the AP device 2 .

FIG. 18 is a diagram showing the relationship between each measurement result in different communication quality measurement modes, the correlation coefficient of the effective throughput of data download, and the communication quality measurement time _T0 in the second embodiment.
The solid line (Beacon count) is the relationship between the measurement result (number of beacon signal receptions per unit time Cb), the correlation coefficient of the effective throughput of data upload, and the measurement time _T0 in the load state of the system shown in FIG. indicates
A dotted line (Beacon interval) indicates the relationship between the measurement result (average beacon signal transmission interval), the correlation coefficient of the effective throughput of data upload, and the measurement time _T0 in the load state of the system shown in FIG.
The one-dot chain line (NFDF retry rate) is the relationship between the measurement result (null frame (NFDF) retransmission rate), the correlation coefficient of the effective throughput of data upload, and the measurement time _T0 in the load state of the system shown in FIG. indicates

In the second embodiment, the load data transmission device 5 uploads a large amount of data per unit time and puts an upload load on the AP device 2 . Even in such a state, the number of receptions Cb (Beacon count [/s]) of the beacon signal per unit time according to the measurement time _T0 and the effective throughput (transmission amount per unit time; Effective throughput [byte/s]) is highly correlated, and it can be seen that communication quality can be detected with better accuracy in a shorter time than other results.

<Third embodiment>
FIG. 19 is a diagram showing the second embodiment in a state where a communication load is applied.
In the example of FIG. 19, the communication system 100 includes an AP device 2, a terminal device 1 wirelessly connected to the AP device 2, a communication terminal device 3, a load data receiving device 4, a load data transmitting device 5, and an observation device 6. is connected to the AP device 2 by wireless communication. In this state, in the second embodiment, the load data receiving device 4 downloads a large amount of data per unit time, the load data transmitting device 5 uploads a large amount of data per unit time, and the AP device 2 with download load and upload load. As in FIG. 15, the two communication terminal devices 3 communicate with an external communication device by using the AP device 2 such as the Internet as a gateway through the AP device 2 . In this state, the terminal device 1 wirelessly communicates with the AP device 2 and estimates the communication quality of data upload and data upload with the AP device 2 . Alternatively, the observation device 6 has a function as the communication quality estimation device 10, and may be connected to the AP device 2 for wireless communication to estimate each communication quality of data upload and data upload with the AP device 2. .

FIG. 20 is a diagram showing the relationship between each measurement result in different communication quality measurement modes, the correlation coefficient of the effective throughput of data download, and the communication quality measurement time _T0 in the third embodiment.
The solid line (Beacon count) is the relationship between the measurement result (number of beacon signal receptions per unit time Cb), the correlation coefficient of the effective throughput of data download, and the measurement time _T0 in the load state of the system shown in FIG. indicates
A dotted line (Beacon interval) indicates the relationship between the measurement result (average beacon signal transmission interval), the correlation coefficient of the effective throughput of data download, and the measurement time _T0 in the load state of the system shown in FIG.
The one-dot chain line (NFDF retry rate) is the relationship between the measurement result (null frame (NFDF) retry rate), the correlation coefficient of the effective throughput of data download, and the measurement time _T0 in the load state of the system shown in FIG. indicates

In the third embodiment, the load data receiving device 4 downloads a large amount of data per unit time, and the load data transmitting device 5 uploads a large amount of data per unit time. Upload load is applied. Even in such a state, the number of beacon signal receptions per unit time Cb (Beacon count [/s]) corresponding to the measurement time _T0 and the effective throughput of data download in the AP device 2 at that time (per unit time The correlation with the effective throughput [byte/s]) is high, and it can be seen that the communication quality can be detected in a shorter time and with better accuracy than the other results.

FIG. 21 is a diagram showing the relationship between each measurement result in different communication quality measurement modes, the correlation coefficient between the effective throughput of data upload, and the communication quality measurement time _T0 in the third embodiment.
The solid line (Beacon count) is the relationship between the measurement result (number of beacon signal receptions per unit time Cb), the correlation coefficient of the effective throughput of data upload, and the measurement time _T0 in the load state of the system shown in FIG. indicates
A dotted line (Beacon interval) indicates the relationship between the measurement result (average beacon signal transmission interval), the correlation coefficient of the effective throughput of data upload, and the measurement time _T0 in the load state of the system shown in FIG.
The one-dot chain line (NFDF retry rate) is the relationship between the measurement result (null frame (NFDF) retransmission rate), the correlation coefficient of the effective throughput of the up-download, and the measurement time _T0 in the load state of the system shown in FIG. indicates

In the third embodiment, the load data receiving device 4 downloads a large amount of data per unit time, and the load data transmitting device 5 uploads a large amount of data per unit time. Upload load is applied. Even in such a state, the number of beacon signal receptions per unit time Cb (Beacon count [/s]) corresponding to the measurement time _T0 and the effective throughput of data upload in the AP device 2 at that time (per unit time The correlation with the effective throughput [byte/s]) is high, and it can be seen that the communication quality can be detected in a shorter time and with better accuracy than the other results.

As can be seen from FIGS. 20 and 21, depending on the load state of the communication system 100, the number of beacon signals received per unit time Cb (Beacon count[/s]) corresponding to the measurement time _T0 and The correlation coefficient with the effective throughput (transmission amount per unit time; effective throughput [byte/s]) of data upload in the AP device 2 changes. For example, in the results of FIG. 20, when the measurement time is about 0.1 second, the correlation coefficient between the number of beacon signal receptions per unit time Cb and the effective throughput of data upload in the AP device 2 at that time is 0.2. Low as the value of what is higher than the neighbors and other results. On the other hand, in the results of FIG. 20, when the measurement time exceeds 1 second, the correlation coefficient between the number of beacon signal receptions per unit time Cb and the effective throughput of data upload in the AP device 2 at that time is 0.5 or more. , which is higher than other results and can be evaluated as a value. In other words, depending on the load state of the communication system 100, the correlation coefficient between the number of receptions Cb of the beacon signal per unit time and the effective throughput of the data upload in the AP device 2 at that time varies according to the measurement time. . Therefore, the measurement time determination unit 13 of the terminal device 1 having the function of the communication quality estimation device 10 and the measurement time determination unit 23 of the AP device 2 variably determine the measurement time based on the load state of the communication system. can be

For example, when both the data download load (mbps) per unit time and the data upload load (mbps) per unit time are equal to or greater than the threshold, the measurement time determination unit 23 of the AP device 2 , set the measurement time _T0 to 1 second ( ¹⁰⁰ seconds) or longer. In addition, when only the data download load (mbps) per unit time is equal to or greater than the threshold value (in the example of FIG. 15), the measurement time determining unit 23 of the AP device 2 sets the measurement time _T0 to 1 second (10 ⁰ seconds). The AP device 2 may notify the terminal device 1 of the set measurement time _T0 , and the terminal device 1 may use the measurement time _T0 to calculate the number of beacon signal receptions Cb per unit time. . Alternatively, if the terminal device 1 can acquire information about the load state from the AP device 2, the measurement time determination unit 13 of the terminal device 1 may similarly set the measurement time _T0 .

FIG. 22 is a diagram showing the minimum configuration of the communication quality estimation device.
FIG. 23 is a diagram showing a processing flow in a communication quality estimation device with a minimum configuration.
The communication quality estimation device 10 (the terminal device 1 or the AP device 2) includes at least a detection means 151, a measurement means 152, and an output means 153.

The detection unit 151 detects transmission of a beacon signal whose transmission is scheduled in advance between devices that perform wireless communication (step S191).
The measuring unit 152 measures the number of beacon signals detected per unit time (step S192).
The output unit 153 outputs information about the communication quality between devices that perform wireless communication based on the number of beacon signals detected per unit time (step S193).

The communication quality estimation device 10 described above has a computer system inside. Each process described above is stored in a computer-readable storage medium in the form of a program, and the process is performed by a computer reading and executing this program. Here, the computer-readable storage medium refers to magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and the like. Alternatively, the computer program may be distributed to a computer via a communication line, and the computer receiving the distribution may execute the program.

Further, the program may be for realizing part of the functions described above. Further, it may be a so-called difference file (difference program) that can realize the above-described functions in combination with a program already recorded in the computer system.

1 Terminal device 2 AP device (wireless communication device)
3... Communication execution terminal device 4... Load data receiver 5... Load data transmitter 6... Observation device 10... Communication quality estimation device 11... Receiver unit (detection means)
12, 22... Measuring part (measuring means)
13, 23 ... measurement time determination unit (measurement time determination means)
14, 24 ... output section (output means)
21... AP function unit (detection means)
151 ... detection means 152 ... measurement means 153 ... output means

Claims (8)

detection means for detecting transmission of a beacon signal pre-scheduled for transmission between devices in wireless communication;
measuring means for measuring the number of detected beacon signals per unit time;
output means for outputting information on communication quality between devices performing wireless communication based on the number of detected beacon signals per unit time;
A communication quality estimation device comprising: 2. The communication quality estimation device according to claim 1, wherein the measurement means calculates the number of detections per unit time by dividing the number of detections of the beacon signals by the measurement time of the beacon signals of the number of detections. . measurement time determination means for determining a measurement time according to the usage status of the device that performs wireless communication;
The communication quality estimation device according to claim 2, comprising: 4. The communication quality estimation according to any one of claims 1 to 3, wherein the output means outputs the number of detected beacon signals per unit time as information on communication quality between devices that perform wireless communication. Device. The output means converts the scale of the amount of data transmission per unit time based on the number of detections of the beacon signal per unit time, and converts the scale of the amount of data transmission per unit time to the scale of the amount of data transmission between the devices performing wireless communication. 4. The communication quality estimation device according to any one of claims 1 to 3, wherein the communication quality information is output as information relating to the communication quality. The communication quality estimation device according to any one of claims 1 to 5, wherein one of the devices that perform wireless communication is a wireless communication device having an access point function. detecting transmission of a beacon signal pre-scheduled for transmission between devices in wireless communication;
measuring the number of detections per unit time of the beacon signal;
A communication quality estimation method, comprising: outputting information about communication quality between the devices performing wireless communication based on the number of detected beacon signals per unit time. The computer of the communication quality estimation device,
detection means for detecting transmission of a beacon signal pre-scheduled for transmission between devices in wireless communication;
measuring means for measuring the number of detected beacon signals per unit time;
output means for outputting information on communication quality between devices performing wireless communication based on the number of beacon signals detected per unit time;
A program that acts as

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