Monitoring device, monitoring system, monitoring method, and program

Abstract

To provide a monitoring device and the like capable of efficiently performing radio communication.SOLUTION: A monitoring device 40 comprises: a mode switching unit 41 for performing radio communication by performing switching between a relay mode capable of relaying radio communication performed by a first radio communication device 20 and a second radio communication device 30 and a monitoring mode for monitoring radio communication performed by the first radio communication device 20 and the second radio communication device 30; a monitoring unit 42 for monitoring first radio communication, which is radio communication performed between the first radio communication device 20 and the second radio communication device 30 without intervention of the mode switching unit 41; and a determination unit 43 for determining whether or not a state of the first radio communication satisfies a first criterion. When it is determined by the determination unit 43 that the state of the first radio communication does not satisfy the first criterion, the mode switching unit 41 performs switching to the relay mode.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a monitoring device and the like. [Background technology]

[0002] Conventionally, monitoring devices that monitor wireless communications have been known. As an example of the monitoring device, Patent Document 1 discloses a site survey system that investigates the communication status in an area where a predetermined system may be constructed before the system is constructed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-66004 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the site survey system of Patent Document 1 cannot improve communication quality when communication quality deteriorates (e.g., wireless communication cannot be maintained, wireless connection is lost, etc.), even if it investigates the status of wireless communication within the system and identifies the cause. Therefore, installing a device (e.g., an access point) with a wireless relay function to relay wireless communication within the system to improve communication quality is considered. However, these measures not only increase costs, but also unnecessarily increase the wireless bandwidth usage rate within the system by constantly relaying wireless communication, which may result in radio interference. Thus, there is a problem in that it is not possible to efficiently investigate wireless communication within the system, analyze the cause, and improve it.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a monitoring device or the like that can efficiently perform wireless communication. [Means for solving the problem]

[0006] In order to solve the above problem, a monitoring device according to one embodiment of the present invention includes a mode switching unit that switches between a relay mode capable of relaying wireless communication between a first wireless communication device and a second wireless communication device and a monitoring mode that monitors wireless communication between the first wireless communication device and the second wireless communication device, a monitoring unit that monitors a first wireless communication, which is wireless communication between the first wireless communication device and the second wireless communication device that does not go through the mode switching unit, and a determination unit that determines whether the state of the first wireless communication satisfies a first criterion, and the mode switching unit switches to the relay mode when the determination unit determines that the state of the first wireless communication does not satisfy the first criterion.

[0007] According to this, when it is determined that the state of the first wireless communication does not satisfy the first criterion, the mode switching unit switches to the relay mode, so that wireless communication can be relayed without providing a relay device or the like separate from the monitoring device. Therefore, since relaying can be performed efficiently according to the state of wireless communication, wireless communication can be performed efficiently.

[0008] Furthermore, one of the first wireless communication device and the second wireless communication device may be an access point and the other may be a station, and when in the relay mode, the mode switching unit may perform a second wireless communication which is wireless communication between the first wireless communication device and the mode switching unit, and a third wireless communication which is wireless communication between the second wireless communication device and the mode switching unit.

[0009] According to this, when one of them is an access point and the other is a station, wireless communication can be efficiently relayed, so that wireless communication can be performed efficiently.

[0010] In addition, the first wireless communication device may be an access point, the second wireless communication device may be a station, and the mode switching unit, when in the relay mode, may operate as a station with respect to the first wireless communication device and as an access point with respect to the second wireless communication device.

[0011] According to this, when the first wireless communication device is an access point and the second wireless communication device is a station, relay can be performed more efficiently according to the wireless communication situation, so that wireless communication can be performed more efficiently.

[0012] In addition, the communication frame transmitted by the first wireless communication includes information indicating a first transmission rate indicating the transmission rate transmitted from the first wireless communication device or the transmission rate transmitted from the second wireless communication device in the first wireless communication. The monitoring unit acquires the respective first transmission rates from the communication frames separately acquired from the first wireless communication device and the second wireless communication device, and the determination unit, based on the respective first transmission rates, determines the second transmission rate, which is the transmission rate in the second wireless communication that is wireless communication performed between the first wireless communication device and the mode switching unit, and the third transmission rate, which is the transmission rate in the third wireless communication that is wireless communication performed between the second wireless communication device and the mode switching unit. When the first transmission rate acquired by the monitoring unit is R1, the estimated second transmission rate is R2, and the estimated third transmission rate is R3, if R1 < R2 × R3 ÷ (R2 + R3), it may be determined that the state of the first wireless communication does not satisfy the first criterion.

[0013] According to this, it is possible to easily determine whether the state of the first wireless communication satisfies the first criterion. Therefore, relay can be performed more efficiently according to the wireless communication situation, so that wireless communication can be performed more efficiently.

[0014] In addition, the communication frame transmitted by the first wireless communication includes retransmission information indicating whether the communication frame has been retransmitted. The monitoring unit acquires one or more pieces of the retransmission information from one or more of the communication frames transmitted during a predetermined period, and the determination unit calculates a retransmission rate during the predetermined period based on the one or more pieces of retransmission information. If the calculated retransmission rate is 0.5 or more, it may be determined that the state of the first wireless communication does not satisfy the first criterion.

[0015] This makes it possible to easily determine whether the state of the first wireless communication satisfies the first criterion, and therefore, more efficient relaying can be performed according to the state of wireless communication, thereby making it possible to perform wireless communication more efficiently.

[0016] Furthermore, when in the relay mode, the mode switching unit may perform a second wireless communication which is a wireless communication between the first wireless communication device and the mode switching unit, and a third wireless communication which is a wireless communication between the second wireless communication device and the mode switching unit, and at least one of the first wireless communication device and the second wireless communication device may disconnect the wireless communication with the mode switching unit when the radio wave strength from the monitoring device is smaller than a predetermined threshold, and when the second wireless communication or the third wireless communication is disconnected, the mode switching unit may switch to the monitoring mode which does not relay the wireless communication between the first wireless communication device and the second wireless communication device.

[0017] According to this, when the radio wave intensity from the monitoring device is lower than a predetermined threshold, the second wireless communication or the third wireless communication is disconnected, and the mode switching unit switches to the monitoring mode when the second wireless communication or the third wireless communication is disconnected. Therefore, when it is better not to perform relaying by the mode switching unit, radio wave interference and the like can be suppressed by not performing relaying by the mode switching unit, and wireless communication can be performed more efficiently.

[0018] Furthermore, when in the relay mode, the mode switching unit may perform a second wireless communication which is a wireless communication between the first wireless communication device and the mode switching unit, and a third wireless communication which is a wireless communication between the second wireless communication device and the mode switching unit, and if the state of the second wireless communication or the third wireless communication does not satisfy a second criterion, switch to the monitoring mode which does not relay the wireless communication between the first wireless communication device and the second wireless communication device, and disconnect the second wireless communication and the third wireless communication.

[0019] According to this, the mode switching unit switches to the monitoring mode when the state of the second wireless communication or the third wireless communication does not satisfy the second criterion. Therefore, when it is better not to perform relaying by the mode switching unit, relaying by the mode switching unit is not performed, thereby suppressing radio wave interference and the like, and wireless communication can be performed more efficiently.

[0020] In addition, in order to solve the above problem, a monitoring system according to one embodiment of the present invention comprises a first wireless communication device, a second wireless communication device, and a monitoring device, wherein the monitoring device has a mode switching unit that switches between a relay mode capable of relaying wireless communication between the first wireless communication device and the second wireless communication device and a monitoring mode that monitors wireless communication between the first wireless communication device and the second wireless communication device to perform wireless communication, a monitoring unit that monitors first wireless communication, which is wireless communication between the first wireless communication device and the second wireless communication device that does not go through the mode switching unit, and a judgment unit that judges whether the state of the first wireless communication satisfies a first criterion, wherein the mode switching unit switches to the relay mode when the judgment unit judges that the state of the first wireless communication does not satisfy the first criterion, and in the relay mode, the first wireless communication device performs second wireless communication with the mode switching unit, and the second wireless communication device performs third wireless communication with the mode switching unit.

[0021] This provides the same effects as the above-described monitoring device.

[0022] In addition, in order to solve the above problem, a monitoring method according to one embodiment of the present invention is a monitoring method performed by a monitoring device, wherein the monitoring device has a mode switching unit that switches between a relay mode capable of relaying wireless communication performed between a first wireless communication device and a second wireless communication device and a monitoring mode that monitors wireless communication performed between the first wireless communication device and the second wireless communication device, and includes a monitoring step of monitoring a first wireless communication that is wireless communication performed between the first wireless communication device and the second wireless communication device and does not go through the mode switching unit, a determination step of determining whether the state of the first wireless communication satisfies a first criterion, and a switching step in which the mode switching unit switches to the relay mode if it is determined in the determination step that the state of the first wireless communication does not satisfy the first criterion.

[0023] This provides the same effects as the above-described monitoring device.

[0024] In order to solve the above problem, a program according to one aspect of the present invention is a program that causes a computer to execute the above monitoring method.

[0025] This provides the same effects as the above-described monitoring device. [Effects of the Invention]

[0026] According to the present invention, a monitoring device or the like can efficiently perform wireless communication. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a schematic diagram showing a monitoring system according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the functional configuration of the monitoring system of FIG. [Figure 3] FIG. 3 is an explanatory diagram for explaining estimation of a transmission rate by a monitoring device of the monitoring system of FIG. [Figure 4] FIG. 4 is a flowchart showing an example of an operation in which the monitoring device of the monitoring system of FIG. 1 switches to the relay mode. [Figure 5] FIG. 5 is a flowchart showing an example of an operation in which the monitoring device of the monitoring system of FIG. 1 switches to the monitoring mode. [Figure 6] FIG. 6 is an explanatory diagram for explaining an example of the operation of FIG. [Figure 7] FIG. 7 is a flowchart showing another example of the operation of the monitoring device of the monitoring system of FIG. 1 switching to the monitoring mode. [Figure 8] FIG. 8 is an explanatory diagram for explaining another example of the operation of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0029] The embodiments described below each show a preferred specific example of the present invention. The numerical values, shapes, materials, components, the arrangement and connection of the components, steps, the order of steps, and the like shown in the following embodiments are merely examples and are not intended to limit the present invention.

[0030] Furthermore, among the components in the following embodiments, those that are not described in the independent claims that represent the highest concept of the present invention will be described as optional components that constitute more preferred embodiments. Note that the same components will be given the same reference numerals, and their description may be omitted.

[0031] (Embodiment) Fig. 1 is a schematic diagram showing a monitoring system 10 according to an embodiment. As shown in Fig. 1, the monitoring system 10 includes a first wireless communication device 20, a second wireless communication device 30, and a monitoring device 40. Fig. 1(a) shows a state in which the monitoring device 40 monitors wireless communication performed between the first wireless communication device 20 and the second wireless communication device 30. Fig. 1(b) shows a state in which the monitoring device 40 relays wireless communication performed between the first wireless communication device 20 and the second wireless communication device 30. An overview of the monitoring system 10 will be described with reference to Fig. 1.

[0032] The first wireless communication device 20 is an access point. The first wireless communication device 20 normally transmits and receives radio waves to and from the second wireless communication device 30, as shown in (a) of FIG.

[0033] The second wireless communication device 30 is a station. The second wireless communication device 30 normally transmits and receives radio waves to and from the first wireless communication device 20, as shown in (a) of Fig. 1, and is capable of performing wireless communication using the radio waves. Furthermore, as shown in (b) of Fig. 1, when direct wireless communication between the first wireless communication device 20 and the second wireless communication device 30 is not possible due to the presence of an obstacle 1, the first wireless communication device 20 and the second wireless communication device 30 can perform wireless communication via a monitoring device 40.

[0034] For example, the first wireless communication device 20 and the second wireless communication device 30 are installed in a factory or an office, and perform wireless communication by Wi-Fi (registered trademark). Note that the first wireless communication device 20 and the second wireless communication device 30 may perform wireless communication by a wireless communication standard other than Wi-Fi (registered trademark).

[0035] The monitoring device 40 is a device that can monitor the wireless communication between the first wireless communication device 20 and the second wireless communication device 30 (see (a) of Figure 1), and can also relay the wireless communication (see (b) of Figure 1) by switching modes as described below.

[0036] As shown in FIG. 1(a), the monitoring device 40 monitors the first wireless communication, which is wireless communication performed between the first wireless communication device 20 and the second wireless communication device 30, and which does not go through the monitoring device 40.

[0037] Also, as shown in (b) of Figure 1, if the first wireless communication does not satisfy the standard (first standard) that can ensure a certain communication quality because the first wireless communication is blocked by an obstacle 1, etc., the monitoring device 40 switches to a mode that can relay communication between the first wireless communication device 20 and the second wireless communication device 30, and relays the communication.

[0038] The monitoring device 40 can automatically improve communication quality and reduce the bandwidth usage rate (reduce radio wave interference) compared to when relaying is always performed.

[0039] The monitoring system 10 will be described in detail below with reference to FIGS.

[0040] Fig. 2 is a block diagram showing the functional configuration of the monitoring system 10 of Fig. 1. Fig. 3 is an explanatory diagram for explaining the estimation of a transmission rate by the monitoring device 40 of the monitoring system 10 of Fig. 1. The functional configuration etc. of the monitoring system 10 will be described with reference to Figs. 2 and 3.

[0041] 2, the monitoring device 40 has a mode switching unit 41, a monitoring unit 42, a determination unit 43, and a storage unit 45. The mode switching unit 41 and the monitoring unit 42 are realized by a wireless communication circuit such as an antenna and a wireless module, the determination unit 43 is realized by a processor or the like, and the storage unit 45 is realized by a memory or the like.

[0042] The mode switching unit 41 has a function (mode switching function) of switching between a mode for monitoring wireless communication performed between the first wireless communication device 20 and the second wireless communication device 30 (monitoring mode) and a mode for relaying wireless communication (relay mode). When a determination unit 43 (described later) determines that the state of the first wireless communication does not satisfy a first criterion, the mode switching unit 41 switches the monitoring device 40 to the relay mode and relays communication between the first wireless communication device 20 and the second wireless communication device 30 by itself. The operation of the determination unit 43 when switching to the relay mode will be described in detail later.

[0043] When in relay mode, the mode switching unit 41 performs second wireless communication, which is wireless communication between the first wireless communication device 20 and the mode switching unit 41, and also performs third wireless communication, which is wireless communication between the second wireless communication device 30 and the mode switching unit 41.

[0044] When the mode switching unit 41 is in the relay mode and receives information addressed to the second wireless communication device 30 from the first wireless communication device 20, the mode switching unit 41 transmits the information to the second wireless communication device 30. When the mode switching unit 41 is in the relay mode and receives information addressed to the first wireless communication device 20 from the second wireless communication device 30, the mode switching unit 41 transmits the information to the first wireless communication device 20.

[0045] In the relay mode, the mode switching unit 41 operates, for example, as a station with respect to the first wireless communication device 20, which is an access point, and operates as an access point with respect to the second wireless communication device 30, which is a station. In this case, switching from the monitoring mode to the relay mode may be performed, for example, by first causing the mode switching unit 41 of the monitoring device 40 to start operating as an access point and perform a wireless connection operation with the second wireless communication device 30, and then causing the mode switching unit 41 to perform a wireless connection operation with the first wireless communication device 20 as a station.

[0046] Furthermore, when in the relay mode, the mode switching unit 41 can switch the monitoring device 40 to a monitoring mode in which the monitoring device 40 does not relay wireless communication performed between the first wireless communication device 20 and the second wireless communication device 30, but monitors the state of that wireless communication. Specifically, the mode switching unit 41 switches the monitoring device 40 to the monitoring mode when, for example, the determination unit 43 determines that the state of the second wireless communication does not satisfy the second criterion. The operation of the determination unit 43 when switching to the monitoring mode will be described in detail later.

[0047] The monitoring unit 42 monitors the first wireless communication when the mode switching unit 41 switches to the monitoring mode. For example, the monitoring unit 42 captures a communication frame transmitted between the first wireless communication device 20 and the second wireless communication device 30 in the monitoring mode. The communication frame includes information indicating the sender and information indicating the destination, and the monitoring unit 42 can determine from the communication frame that wireless communication is being performed between the first wireless communication device 20 and the second wireless communication device 30, and can therefore monitor the first wireless communication.

[0048] For example, a communication frame transmitted by the first wireless communication includes a first transmission rate, which is the transmission rate in the first wireless communication. For example, a communication frame transmitted from the first wireless communication device 20 includes a first transmission rate indicating the transmission rate from the first wireless communication device 20, and a communication frame transmitted from the second wireless communication device 30 includes a first transmission rate indicating the transmission rate from the second wireless communication device 30. (These rates are not necessarily the same value.) The monitor 42 acquires the respective first transmission rates from communication frames acquired separately from the first wireless communication device 20 and the second wireless communication device 30. Furthermore, a communication frame transmitted in the first wireless communication includes retransmission information indicating whether the communication frame has been retransmitted, and the monitor 42 acquires one or more pieces of retransmission information from one or more communication frames transmitted during a predetermined period. The monitor 42 also acquires bandwidth utilization rate, route information, etc.

[0049] As described above, both the mode switching unit 41 and the monitoring unit 42 are realized as hardware using a wireless module, an antenna, etc. However, while the monitoring unit 42 only receives radio waves, the mode switching unit 41, as described above, transmits / receives radio waves and operates as both an access point function and a station function.

[0050] The determination unit 43 determines whether or not the state of the first wireless communication satisfies a first criterion. For example, the first criterion is a criterion that can ensure a certain level of communication quality, and when the state of the first wireless communication satisfies the first criterion, the first wireless communication can ensure a certain level of communication quality.

[0051] (1st standard) Here, for one of the first criteria, there is an idea of using the transmission rate as the switching criterion. For example, the determination unit 43 estimates a second transmission rate, which is the transmission rate in the second wireless communication, and a third transmission rate, which is the transmission rate in the third wireless communication, based on the first transmission rate among the monitoring data captured in the monitoring mode. For example, the determination unit 43 obtains one or more first transmission rates from one or more communication frames transmitted from the first wireless communication device 20 in a predetermined period (for example, 1 second), and estimates the second transmission rate based on the maximum value of the first transmission rate (the maximum rate that could be demodulated without error). For example, the determination unit 43 sets the maximum value as the second transmission rate. Also, the determination unit 43 obtains one or more first transmission rates from one or more communication frames transmitted from the second wireless communication device 30 in a predetermined period, and estimates the third transmission rate based on the maximum value of the first transmission rate. For example, the determination unit 43 sets the maximum value as the third transmission rate. Specifically, for example, when two first transmission rates of 24 Mbps and 36 Mbps transmitted from the first wireless communication device 20 to the second wireless communication device 30 are obtained, and in the second wireless communication device 30, the frame transmitted at 24 Mbps can be demodulated without error and the frame transmitted at 36 Mbps cannot be correctly demodulated, it can be estimated that the second transmission rate is likely to enable error - free implementation of the second wireless communication when using 24 Mbps, and 24 Mbps is set as the second transmission rate. Similarly, the third transmission rate can be estimated. As shown in FIG. 3, the determination unit 43 sets the first transmission rate obtained by the monitoring unit 42 as R1, the estimated second transmission rate as R2, and the estimated third transmission rate as R3. When the transmission rate in the case of relay by the mode switching unit 41 in the relay mode is R, the transmission rate is estimated by R = R2×R3÷(R2 + R3). When R1 < R, that is, when R1 < R2×R3÷(R2 + R3), it is determined that the state of the first wireless communication does not meet the first criterion. Note that when R2 << R3, R ≈ R2, and when R2 ≈ R3, R ≈ R2 / 2.

[0052] Another possible first criterion is to use latency as a criterion for switching. For example, the determination unit 43 calculates a retransmission rate for a predetermined period based on one or more pieces of retransmission information, and if the calculated retransmission rate is 0.5 or higher, determines that the first wireless communication does not satisfy the first criterion. This is because the number of transmissions and receptions in relay mode is twice the number of transmissions and receptions in monitoring mode due to the relaying of the monitoring device 40. Therefore, even if the retransmission rate is zero, the latency in relay mode is less than half the latency of the first wireless communication in monitoring mode. Specifically, the determination unit 43 calculates the retransmission rate by dividing the number of communication frames retransmitted in a predetermined period by the number of communication frames transmitted in the predetermined period. For example, if five pieces of retransmission information are acquired in a predetermined period (e.g., one second), and two of the five pieces of retransmission information are retransmitted and three of the five pieces are not retransmitted, the determination unit 43 divides 2 by 5 to calculate the retransmission rate as 0.4. In this case, the determination unit 43 determines that the state of the first wireless communication satisfies the first criterion because the calculated retransmission rate is not equal to or greater than 0.5.

[0053] The storage unit 45 stores various information (for example, communication frames, bandwidth usage rates, and route information) acquired by the monitoring unit .

[0054] Fig. 4 is a flowchart showing an example of an operation of switching to the relay mode by the monitoring device 40 of the monitoring system 10 of Fig. 1. With reference to Fig. 4, an example of an operation of switching to the relay mode by the monitoring device 40 of the monitoring system 10 will be described.

[0055] As shown in FIG. 4, the monitoring unit 42 monitors the first wireless communication (monitoring step) (step S1).

[0056] The determination unit 43 determines whether or not the state of the first wireless communication satisfies a first criterion (determination step) (step S2).

[0057] If the state of the first wireless communication satisfies the first criterion (Yes in step S2), the determination unit 43 again determines whether or not the state of the first wireless communication satisfies the first criterion (determination step) (step S2).

[0058] When the determination unit 43 determines that the state of the first wireless communication does not satisfy the first criterion (No in step S2), the mode switching unit 41 switches to the relay mode (switching step) (step S3).

[0059] Whether the first criterion mentioned above is based on transmission rate or latency depends on which is prioritized for transmission and reception. Generally, when transmission rate is prioritized, multiple data tends to be sent together using high-throughput aggregation, resulting in large frame sizes. On the other hand, when latency is prioritized, aggregation is avoided, so frame sizes tend to be small. In monitoring mode, it is desirable to include such packet sizes as monitoring data and select the first criterion method based on this.

[0060] (Switching from relay mode to monitoring mode) Fig. 5 is a flowchart showing an example of the operation of the monitoring device 40 of the monitoring system 10 of Fig. 1 switching to monitoring mode. Fig. 6 is an explanatory diagram for explaining the operation of Fig. 5. An example of the operation of the monitoring device 40 of the monitoring system 10 switching to monitoring mode will be described with reference to Fig. 5 and Fig. 6. In this example, the first wireless communication device 20 is an access point, and the second wireless communication device 30 is a station.

[0061] As shown in (a) of Fig. 6, in the relay mode, the second wireless communication device 30 measures the radio wave intensity (RSSI) from the monitoring device 40 in the third wireless communication. When the radio wave intensity in the third wireless communication decreases and becomes smaller than a predetermined threshold, the second wireless communication device 30 disconnects the third wireless communication as shown in (b) of Fig. 6. For example, the predetermined threshold is set by a user or the like and stored in advance in the storage unit 45.

[0062] 6(c), when the second wireless communication device 30 disconnects the third wireless communication, the second wireless communication device 30 performs roaming. When the third wireless communication is disconnected, the monitoring device 40 detects that the third wireless communication has been disconnected.

[0063] 6(d), after roaming, the second wireless communication device 30 performs the first wireless communication with the first wireless communication device 20. When the monitoring device 40 detects that the third wireless communication has been disconnected, it disconnects the second wireless communication and switches to the monitoring mode.

[0064] Based on the explanation of Fig. 6, the operation flow of the mode switching unit 41 of the monitoring device 40 will now be explained using Fig. 5. When the mode switching unit 41 detects that the third wireless communication has been disconnected (step S11), it disconnects the second wireless communication (step S12) and switches to the monitoring mode (step S13). Note that step S13 may be performed before step S12. In the flow of Fig. 5, the switch to the monitoring mode is triggered by the disconnection of the third wireless communication, and this is because the second wireless communication device 30 has determined that the RSSI in the third wireless communication has fallen below a predetermined RSSI threshold, and the monitoring device 40 is in a passive state.

[0065] The first wireless communication device 20 may measure the radio wave intensity from the monitoring device 40 in the second wireless communication, and may disconnect the second wireless communication when the radio wave intensity from the monitoring device 40 in the second wireless communication decreases and becomes smaller than a predetermined threshold. In this case, when the mode switching unit 41 detects that the second wireless communication has been disconnected, it disconnects the third wireless communication and switches to the monitoring mode.

[0066] Fig. 7 is a flowchart showing another example of the operation of the monitoring device 40 of the monitoring system 10 of Fig. 1 switching to monitoring mode. Fig. 8 is an explanatory diagram for explaining the operation of Fig. 7. Another example of the operation of the monitoring device 40 of the monitoring system 10 switching to monitoring mode will be described with reference to Figs. 7 and 8. In this example, the first wireless communication device 20 is an access point, and the second wireless communication device 30 is a station.

[0067] As shown in Fig. 8(a), the monitoring device 40 monitors the status of the second wireless communication and the third wireless communication. When the status of the second wireless communication or the third wireless communication deteriorates and no longer satisfies the second criterion, the monitoring device 40 disconnects the second wireless communication, as shown in Fig. 8(b). The second criterion here is, for example, a decrease in the amount of traffic relayed by the monitoring device 40 itself or a deterioration in the communication conditions during relaying.

[0068] As shown in FIG. 8(c), when the monitoring device 40 disconnects the second wireless communication, it also disconnects the third wireless communication.

[0069] 8(d), when the third wireless communication is disconnected, the second wireless communication device 30 performs a scan and then performs the first wireless communication with the first wireless communication device 20. When the third wireless communication is disconnected, the monitoring device 40 switches to the monitoring mode.

[0070] From here, the operation flow of the mode switching unit 41 of the monitoring device 40 will be described with reference to Fig. 7 based on the explanation of Fig. 8. As shown in Fig. 7, the determination unit 43 determines whether the state of the second wireless communication satisfies the second criterion (step S21).

[0071] If the state of the second wireless communication satisfies the second criterion (Yes in step S21), the determination unit 43 again determines whether or not the state of the second wireless communication satisfies the second criterion (step S21).

[0072] If the state of the second wireless communication does not satisfy the second criterion (No in step S21), the mode switching unit 41 disconnects the second wireless communication (step S22), disconnects the third wireless communication (step S23), and switches to the monitoring mode (step S24). Note that the order of steps S22, S23, and S24 is not particularly limited.

[0073] 7 shows a case where the determination unit 43 determines whether the state of the second wireless communication satisfies the second criterion, but similarly, the determination unit 43 may determine whether the state of the third wireless communication satisfies the second criterion. In this case, when the state of the third wireless communication does not satisfy the second criterion, the mode switching unit 41 may disconnect the second wireless communication and the third wireless communication and switch to the monitoring mode.

[0074] As the second criterion here, R may be calculated using the above-mentioned formula using the actual transmission rate value in relay mode instead of R2 and R3, and R may be set as R>R1 in terms of the magnitude relationship with R1 recorded when monitoring mode was operating normally, and the second wireless communication and the third wireless communication may be disconnected if this is no longer met.

[0075] The monitoring system 10 has been described above.

[0076] The monitoring device 40 of this embodiment includes a mode switching unit 41 that switches between a relay mode capable of relaying wireless communication between the first wireless communication device 20 and the second wireless communication device 30 and a monitoring mode that monitors wireless communication between the first wireless communication device 20 and the second wireless communication device 30, a monitoring unit 42 that monitors the first wireless communication, which is wireless communication between the first wireless communication device 20 and the second wireless communication device 30 that does not go through the mode switching unit 41, and a judgment unit 43 that judges whether the state of the first wireless communication satisfies a first criterion, and the mode switching unit 41 switches to the relay mode when the judgment unit 43 judges that the state of the first wireless communication does not satisfy the first criterion.

[0077] According to this, when it is determined that the state of the first wireless communication does not satisfy the first criterion, the mode switching unit 41 switches to the relay mode, so that wireless communication can be relayed without providing a relay device or the like separate from the monitoring device 40. Therefore, since relaying can be performed efficiently according to the state of wireless communication, wireless communication can be performed efficiently.

[0078] In addition, in the monitoring device 40 according to this embodiment, one of the first wireless communication device 20 and the second wireless communication device 30 is an access point and the other is a station, and when in relay mode, the mode switching unit 41 performs second wireless communication, which is wireless communication between the first wireless communication device 20 and the mode switching unit 41, and performs third wireless communication, which is wireless communication between the second wireless communication device 30 and the mode switching unit 41.

[0079] According to this, when one of them is an access point and the other is a station, wireless communication can be efficiently relayed, so that wireless communication can be performed efficiently.

[0080] Furthermore, the first wireless communication device 20 is an access point, and the second wireless communication device 30 is a station, and the mode switching unit 41 in the monitoring device 40 according to this embodiment operates as a station with respect to the first wireless communication device 20 and as an access point with respect to the second wireless communication device 30 when in relay mode.

[0081] According to this, when the first wireless communication device 20 is an access point and the second wireless communication device 30 is a station, relaying can be performed more efficiently depending on the wireless communication situation, so that wireless communication can be performed more efficiently.

[0082] Also, in the monitoring device 40 according to the present embodiment, the communication frame transmitted by the first wireless communication includes information indicating a first transmission rate indicating the transmission rate transmitted from the first wireless communication device 20 or the transmission rate transmitted from the second wireless communication device in the first wireless communication. The monitoring unit 42 acquires each first transmission rate from the communication frames separately acquired from the first wireless communication device 20 and the second wireless communication device 30. The determination unit 43 estimates a second transmission rate, which is the transmission rate in the second wireless communication that is the wireless communication performed between the first wireless communication device 20 and the mode switching unit 41, and a third transmission rate, which is the transmission rate in the third wireless communication that is the wireless communication performed between the second wireless communication device 30 and the mode switching unit 41, based on each first transmission rate. When the first transmission rate acquired by the monitoring unit 42 is R1, the estimated second transmission rate is R2, and the estimated third transmission rate is R3, if R1 < R2 × R3 ÷ (R2 + R3), it is determined that the state of the first wireless communication does not satisfy the first criterion.

[0083] According to this, it is possible to easily determine whether or not the state of the first wireless communication satisfies the first criterion. Therefore, relay can be performed more efficiently according to the wireless communication situation, and wireless communication can be performed more efficiently.

[0084] Also, in the monitoring device 40 according to the present embodiment, the communication frame transmitted by the first wireless communication includes retransmission information indicating whether the communication frame has been retransmitted. The monitoring unit 42 acquires one or more retransmission information from one or more communication frames transmitted in a predetermined period. The determination unit 43 calculates a retransmission rate in the predetermined period based on the one or more retransmission information, and if the calculated retransmission rate is 0.5 or more, it is determined that the state of the first wireless communication does not satisfy the first criterion.

[0085] According to this, it is possible to easily determine whether or not the state of the first wireless communication satisfies the first criterion. Therefore, relay can be performed more efficiently according to the wireless communication situation, and wireless communication can be performed more efficiently.

[0086] Furthermore, in the monitoring device 40 according to this embodiment, when the mode switching unit 41 is in relay mode, it performs a second wireless communication which is wireless communication between the first wireless communication device 20 and the mode switching unit 41, and a third wireless communication which is wireless communication between the second wireless communication device 30 and the mode switching unit 41; when the radio wave intensity from the monitoring device 40 is smaller than a predetermined threshold, at least one of the first wireless communication device 20 and the second wireless communication device 30 disconnects the wireless communication with the mode switching unit 41; and when the second wireless communication or the third wireless communication is disconnected, the mode switching unit 41 switches to a monitoring mode which does not relay the wireless communication between the first wireless communication device 20 and the second wireless communication device 30.

[0087] According to this, when the radio wave intensity from monitoring device 40 is lower than a predetermined threshold, the second wireless communication or the third wireless communication is disconnected, and mode switching unit 41 switches to monitoring mode when the second wireless communication or the third wireless communication is disconnected. Therefore, when it is better not to perform relaying by mode switching unit 41, relaying by mode switching unit 41 can be prevented to suppress radio wave interference, etc., and wireless communication can be performed more efficiently.

[0088] Furthermore, in the monitoring device 40 according to this embodiment, when in relay mode, the mode switching unit 41 performs a second wireless communication, which is wireless communication between the first wireless communication device 20 and the mode switching unit 41, and a third wireless communication, which is wireless communication between the second wireless communication device 30 and the mode switching unit 41, and if the state of the second wireless communication or the third wireless communication does not satisfy the second criterion, the mode switching unit 41 switches to a monitoring mode that does not relay the wireless communication between the first wireless communication device 20 and the second wireless communication device 30, and disconnects the second wireless communication and the third wireless communication.

[0089] According to this, the mode switching unit 41 switches to the monitoring mode when the state of the second wireless communication or the third wireless communication does not satisfy the second criterion. Therefore, when it is better not to perform relaying by the mode switching unit 41, relaying by the mode switching unit 41 can be prevented to suppress radio wave interference, etc., and wireless communication can be performed more efficiently.

[0090] Furthermore, the monitoring system 10 according to this embodiment includes a first wireless communication device 20, a second wireless communication device 30, and a monitoring device 40. The monitoring device 40 has a mode switching unit 41 that switches between a relay mode capable of relaying wireless communication between the first wireless communication device 20 and the second wireless communication device 30 and a monitoring mode that monitors wireless communication between the first wireless communication device 20 and the second wireless communication device 30, a monitoring unit 42 that monitors the first wireless communication, which is wireless communication between the first wireless communication device 20 and the second wireless communication device 30 that does not go through the mode switching unit 41, and a judgment unit 43 that judges whether the state of the first wireless communication satisfies a first criterion. When the judgment unit 43 judges that the state of the first wireless communication does not satisfy the first criterion, the mode switching unit 41 switches to the relay mode. In the relay mode, the first wireless communication device 20 performs a second wireless communication with the mode switching unit 41, and the second wireless communication device 30 performs a third wireless communication with the mode switching unit 41.

[0091] This provides the same effects as the monitoring device 40 described above.

[0092] Furthermore, the monitoring method according to this embodiment is a monitoring method performed by the monitoring device 40, and the monitoring device 40 has a mode switching unit 41 that switches between a relay mode capable of relaying wireless communication performed between the first wireless communication device 20 and the second wireless communication device 30 and a monitoring mode that monitors wireless communication performed between the first wireless communication device 20 and the second wireless communication device 30, and performs wireless communication, and includes a monitoring step (step S1) of monitoring the first wireless communication, which is wireless communication performed between the first wireless communication device 20 and the second wireless communication device 30 and does not go through the mode switching unit 41, a determination step (step S2) of determining whether the state of the first wireless communication satisfies a first criterion, and a switching step (step S3) in which the mode switching unit 41 switches to the relay mode if it is determined in the determination step that the state of the first wireless communication does not satisfy the first criterion.

[0093] This provides the same effects as the monitoring device 40 described above.

[0094] Moreover, the program according to the present embodiment is a program that causes a computer to execute the above-described monitoring method.

[0095] This provides the same effects as the monitoring device 40 described above.

[0096] (Other embodiments) In the monitoring device 40 in the above-described embodiment, one wireless module may serve as both the mode switching unit 41 and the monitoring unit 42, or, without being limited to this, multiple wireless modules may each have their own dedicated functions and switch modes by turning power on and off, etc.

[0097] In the above-described embodiment, the first wireless communication device 20 is an access point and the second wireless communication device 30 is a station. However, the present invention is not limited to this. For example, the first wireless communication device 20 may be a station and the second wireless communication device 30 may be an access point. The first wireless communication device 20 and the second wireless communication device 30 may be two nodes among a plurality of nodes that form a mesh network. In this case, the mode switching unit 41 may wirelessly communicate with the node using radio waves transmitted from the node.

[0098] The present invention can be realized not only as an apparatus or a system, but also as a method in which the processing means constituting the apparatus or system are steps, as a program that causes a computer to execute those steps, as a non-transitory recording medium such as a computer-readable CD-ROM on which the program is recorded, or as information, data, or signals that represent the program.These programs, information, data, and signals may be distributed via a communication network such as the Internet.

[0099] While the monitoring device and the like of the present invention have been described above based on the embodiments, the present invention is not limited to these embodiments. As long as they do not deviate from the spirit of the present invention, various modifications that a person skilled in the art can make to the present embodiments and configurations constructed by combining components of different embodiments are also included within the scope of the present invention. [Industrial Applicability]

[0100] The present invention can be used as a device for monitoring wireless communications, etc. [Explanation of symbols]

[0101] 1. Obstacles 10. Surveillance System 20 First wireless communication device 30 Second wireless communication device 40 Monitoring equipment 41 Mode switching section 42 Monitoring Department 43 Judgment section 45 Storage section

Claims

1. a mode switching unit that switches between a relay mode capable of relaying wireless communication between a first wireless communication device and a second wireless communication device and a monitoring mode that monitors wireless communication between the first wireless communication device and the second wireless communication device, and performs wireless communication; a monitoring unit that monitors a first wireless communication that is wireless communication performed between the first wireless communication device and the second wireless communication device without going through the mode switching unit; a determination unit that determines whether or not a state of the first wireless communication satisfies a first criterion; the mode switching unit switches to the relay mode when the determination unit determines that the state of the first wireless communication does not satisfy the first criterion. monitoring equipment.

2. one of the first wireless communication device and the second wireless communication device is an access point and the other is a station; the mode switching unit, in the relay mode, performs second wireless communication which is wireless communication performed between the first wireless communication device and the mode switching unit, and performs third wireless communication which is wireless communication performed between the second wireless communication device and the mode switching unit. The monitoring device of claim 1 .

3. the first wireless communication device is an access point; the second wireless communication device is a station; the mode switching unit, when in the relay mode, operates as a station with respect to the first wireless communication device and as an access point with respect to the second wireless communication device; The monitoring device according to claim 2 .

4. the communication frame transmitted by the first wireless communication includes information indicating a first transmission rate indicating a transmission rate transmitted from the first wireless communication device or a transmission rate transmitted from the second wireless communication device in the first wireless communication; the monitoring unit acquires the first transmission rate from the communication frames acquired separately from the first wireless communication device and the second wireless communication device, the determination unit estimates, based on the respective first transmission rates, a second transmission rate which is a transmission rate in a second wireless communication which is wireless communication performed between the first wireless communication device and the mode switching unit, and a third transmission rate which is a transmission rate in a third wireless communication which is wireless communication performed between the second wireless communication device and the mode switching unit, and determines that the state of the first wireless communication does not satisfy the first criterion if R1<R2×R3÷(R2+R3), where R1 is the first transmission rate acquired by the monitoring unit, R2 is the estimated second transmission rate, and R3 is the estimated third transmission rate. The monitoring device of claim 1 .

5. the communication frame transmitted by the first wireless communication includes retransmission information indicating whether the communication frame is a retransmission, the monitoring unit acquires one or more pieces of retransmission information from one or more communication frames transmitted during a predetermined period; the determination unit calculates a retransmission rate for the predetermined period based on the one or more pieces of retransmission information, and determines that the state of the first wireless communication does not satisfy the first criterion when the calculated retransmission rate is 0.5 or more. The monitoring device of claim 1 .

6. the mode switching unit, in the relay mode, performs second wireless communication which is wireless communication performed between the first wireless communication device and the mode switching unit, and performs third wireless communication which is wireless communication performed between the second wireless communication device and the mode switching unit; at least one of the first wireless communication device and the second wireless communication device disconnects wireless communication with the mode switching unit when radio wave intensity from the monitoring device is lower than a predetermined threshold; the mode switching unit switches to the monitoring mode in which wireless communication performed between the first wireless communication device and the second wireless communication device is not relayed when the second wireless communication or the third wireless communication is disconnected. The monitoring device of claim 1 .

7. The mode switching unit In the relay mode, a second wireless communication is performed which is a wireless communication performed between the first wireless communication device and the mode switching unit, and a third wireless communication is performed which is a wireless communication performed between the second wireless communication device and the mode switching unit, If the state of the second wireless communication or the third wireless communication does not satisfy a second criterion, switching to the monitoring mode in which wireless communication performed between the first wireless communication device and the second wireless communication device is not relayed, and disconnecting the second wireless communication and the third wireless communication. The monitoring device of claim 1 .

8. a first wireless communication device, a second wireless communication device, and a monitoring device; The monitoring device has a mode switching unit that switches between a relay mode capable of relaying wireless communication performed between the first wireless communication device and the second wireless communication device and a monitoring mode that monitors wireless communication performed between the first wireless communication device and the second wireless communication device, a monitoring unit that monitors first wireless communication, which is wireless communication performed between the first wireless communication device and the second wireless communication device and does not go through the mode switching unit, and a determination unit that determines whether or not a state of the first wireless communication satisfies a first criterion, the mode switching unit switches to the relay mode when the determination unit determines that the state of the first wireless communication does not satisfy the first criterion; In the relay mode, the first wireless communication device performs second wireless communication with the mode switching unit, and the second wireless communication device performs third wireless communication with the mode switching unit. Surveillance system.

9. A monitoring method performed by a monitoring device, the monitoring device includes a mode switching unit that switches between a relay mode capable of relaying wireless communication performed between a first wireless communication device and a second wireless communication device and a monitoring mode that monitors wireless communication performed between the first wireless communication device and the second wireless communication device, and performs wireless communication; a monitoring step of monitoring a first wireless communication that is wireless communication performed between the first wireless communication device and the second wireless communication device without using the mode switching unit; a determining step of determining whether a state of the first wireless communication satisfies a first criterion; a switching step of the mode switching unit switching to the relay mode when it is determined in the determining step that the state of the first wireless communication does not satisfy the first criterion. Monitoring method.

10. A program that causes a computer to execute the monitoring method according to claim 9.

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