JP5954157B2 - Information processing apparatus and program - Google Patents

Description

  Some embodiments relate to an information processing apparatus and a program.

  In recent years, for example, information processing apparatuses such as smartphones, mobile phones, PDAs, electronic notebooks, personal computers (PCs), and tablet PCs are equipped with wireless communication devices. The wireless communication device includes, for example, a wireless local area network (LAN). These information processing apparatuses connect to, for example, an access point via a wireless communication device and transmit / receive information.

  FIG. 1 is a diagram illustrating a configuration of a system 100 for wireless communication. In FIG. 1, system 100 includes a station 101 and an access point 102. The station 101 is, for example, the information processing apparatus 1 equipped with a wireless communication device. In the example shown in FIG. 1, the station 101 operates as a slave unit for wireless communication, and the access point 102 operates as a master unit for wireless communication. The access point 102 sends out a beacon 103 as notification information. In addition, the station 101 establishes a connection with the access point 102 and performs data transmission / reception 104 by wireless communication.

  FIG. 2 is a diagram illustrating a sequence of wireless communication between the station 101 and the access point 102. The wireless communication may be, for example, communication using a wireless LAN. The access point 102 can receive a connection request from a station 101 in the vicinity and can establish a wireless connection with the station 101 in the vicinity. When each station 101 requests connection to the access point 102, the station 101 transmits a connection request called a probe request to the access point 102 (process 201). The probe request includes the SSID (Service Set Identifier) of the access point to which connection is requested. The SSID is an identifier for identifying an access point. When the access point 102 receives the probe request including the SSID of its own device, the access point 102 returns a connection response called a probe response to the station 101 that has transmitted the probe request (process 202). By transmitting and receiving the probe request and the probe response, the station 101 that transmitted the probe request and the access point 102 recognize the existence of each other.

  Subsequently, the station 101 and the access point 102 authenticate each other using a predetermined authentication method in order to confirm whether or not the other party can be connected to each other (process 203). This exchange of authentication is called, for example, authentication. If it is confirmed by authentication that the station 101 can be connected to, the connection is established by a process called association (process 204). The access point periodically sends a signal called a beacon 103 to the periphery (process 205). For example, the station 101 can recognize the presence of the access point 102 by the beacon 103. Alternatively, the station 101 can know whether or not the received data addressed to itself is in the access point 102 based on the information added to the beacon 103. The station 101 transmits / receives data to / from the access point 102 via the established connection as necessary (process 206). For example, as described above, the station 101 establishes a connection with the access point 102 and transmits / receives data by wireless communication.

  With respect to the wireless communication exemplified above, when wireless connection with the access point device is impossible, power supply to the connected wireless device is stopped, so that unnecessary battery consumption can be prevented. Technology is known. There is also known a wireless LAN system that can prevent a decrease in throughput even when an access point fails. There is known a communication device capable of establishing one-to-one high-speed non-contact communication with a device located at a short distance without interference. (For example, see Patent Document 1 to Patent Document 3)

JP 2005-167893 A JP 2000-349787 A JP 2006-186418 A

  However, for example, when an event that affects the entire region, such as a disaster or a power failure, occurs, a plurality of access points existing in the region may go down all at once. In this case, even if a search is made for an access point to which a station can be connected in the area, there is a situation where the possibility of finding a connectable access point is low because most of the peripheral access points are down. Therefore, there is a possibility that power consumed when searching for an access point to which the station can be connected is wasted. Therefore, some embodiments have an object of providing a technique capable of suppressing power consumption by a wireless communication device when an event that affects the entire region such as a disaster or a power failure occurs.

  An information processing apparatus according to one aspect of the present invention includes a wireless communication device that performs wireless communication, a generation unit, a determination unit, and a change unit. The generation unit receives radio waves from a plurality of peripheral access points at a plurality of timings using a wireless communication device. The generation unit generates reception intensity history information in which the reception intensity of the radio wave received at each timing of the plurality of timings is associated with the access point identified by the identifier included in the received radio wave. In the reception strength history information, the determination unit cannot measure the reception strength at the second timing subsequent to the first timing among the access points whose reception strength at the first timing is equal to or greater than a predetermined threshold. It is determined whether the access points occupy a predetermined ratio or more. When the determination unit determines that the ratio of the access points that cannot be measured is less than a predetermined ratio, the change unit determines a time interval until the next reception of radio waves from the neighboring access points as the first time interval. Set to time interval. In addition, when the changing unit determines that the ratio occupied by the access points that are not measurable by the determination unit is equal to or greater than a predetermined rate, the time interval until the next reception of radio waves from neighboring access points is determined. Change to a second time interval longer than the first time interval.

  According to the above-described aspect, for example, when an event that affects the entire region such as a disaster or a power failure occurs, power consumption by the wireless communication device can be suppressed.

1 is a diagram illustrating a configuration of a wireless communication system. It is a figure which illustrates the sequence of radio | wireless communication. It is a graph which illustrates the relationship between the reception intensity of the radio wave from the access point received in the station, and the distance between the station and the access point. It is a graph which illustrates the receiving intensity of the electric wave from the access point received by a station when an access point goes down. It is a figure which illustrates the reception intensity | strength of the electromagnetic wave from the access point received in a station when the event which brings down the access point of the periphery of a station simultaneously generate | occur | produces. It is a graph which illustrates the number of the access points which can receive an electromagnetic wave in a station, when the event which brings down several access points of the circumference of a station simultaneously occurs. 6 is a graph illustrating time intervals for performing a scan of an access point, according to some embodiments. It is a figure which shows the example which turns off a wireless LAN function, when the event which brings down several access points which exist in the whole area according to some embodiment at the same time generate | occur | produces. It is a figure which illustrates the functional block structure of the information processing apparatus which concerns on some embodiment. It is a figure which illustrates receiving intensity history information concerning a 1st embodiment. It is a figure which illustrates the operation | movement flow of the production | generation process of the reception intensity history information performed by the control part of a station. It is a figure which illustrates the operation | movement flow of the change process of the time interval until it performs the next scan when the event which brings down the access point of the whole area based on 1st Embodiment generate | occur | produces. It is a figure which illustrates the operation | movement flow of the return process based on 1st Embodiment. It is a figure which illustrates receiving intensity history information concerning a 2nd embodiment. It is a figure which illustrates the operation | movement flow of the change process of the time interval until it performs the next scan when the event which brings down the access point of the whole area based on 2nd Embodiment generate | occur | produces. It is a figure which illustrates change of the number of probe requests which other stations which can be received in a station originate in a case where a plurality of access points which exist in the whole area down according to a 3rd embodiment go down all at once. It is a figure which illustrates the operation | movement flow of the change process of the time interval until the next scan is performed when the event which brings down the access point of the whole area based on 3rd Embodiment generate | occur | produces. It is a figure which illustrates the hardware constitutions of the computer for implement | achieving the information processing apparatus which functions as a station based on some embodiment. It is a figure which illustrates control which switches on and off of the electric power supply to the wireless LAN communication apparatus which concerns on some embodiment.

  Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol was attached | subjected to the corresponding element in several drawing. In the following description, a wireless LAN is described as an example of wireless communication, but the embodiment is not limited to this. For example, the embodiments may be applied to other wireless communication schemes.

  FIG. 3 is a graph illustrating the relationship between the reception intensity of radio waves from the access point 102 received at the station 101 and the distance between the station 101 and the access point 102. In FIG. 3, the vertical axis represents the radio wave reception intensity from the access point 102, and the horizontal axis represents the distance between the station 101 and the access point 102. As shown in the figure, the reception intensity decreases as the distance increases. When the reception intensity falls below a certain level, the station 101 cannot normally transmit / receive data to / from the access point 102. For example, a wireless LAN has a communication distance of about 100 m in a place with good visibility. If the station 101 moves and is further away, it becomes out of service area and is disconnected. In such a disconnection that occurs when the distance between the station 101 and the access point 102 is increased, the radio wave reception intensity gradually weakens, eventually resulting in an incommunicable reception intensity, and the connection is disconnected. The

  However, when some failure occurs in the access point 102 and the access point 102 goes down, the reception intensity of the radio wave from the access point 102 received by the station 101 suddenly decreases regardless of the distance. FIG. 4 is a graph illustrating the reception intensity of radio waves from the access point 102 received by the station 101 when some failure occurs and the access point 102 goes down. In FIG. 4, the vertical axis represents the reception intensity of radio waves from the access point 102 received by the station 101, and the horizontal axis represents time. In the example shown in FIG. 4, the station 101 is not moving, so that radio waves can be received from the access point 102 with a stable reception intensity before the access point 102 goes down. However, radio waves are not transmitted from the access point 102 after a failure occurs in the access point 102 that is the connection destination and the access point 102 is down. Therefore, the reception intensity of the radio wave received from the access point 102 received by the station 101 suddenly drops to zero, thereby disconnecting the connection between the station 101 and the access point 102.

  As described above, the disconnection of the connection due to the access point 102 being down is the disconnection of the connection due to the separation of the distance described above, and the tendency of the decrease in the reception intensity of the radio wave from the access point 102 detected at the station 101. Is different. For this reason, whether the cause of the disconnection is due to the distance being removed or the access point 102 is down due to the tendency of the radio wave reception intensity of the access point 102 detected at the station 101 to decrease. It is possible to estimate.

  Here, when the access point 102 is down due to, for example, the occurrence of a disaster or a power outage, the effect is not limited to only one access point, but a plurality of access points in the region where the disaster or power outage occurred. 102. Then, a plurality of access points 102 in the entire region may go down at the same time. FIG. 5 exemplifies reception strength of radio waves received from a plurality of peripheral access points 102 received by the station 101 when a plurality of access points 102 around the station 101 simultaneously fail and go down. FIG.

  In FIG. 5, the vertical axis represents the radio wave reception intensity from the access point 102 received by the station 101. The horizontal axis indicates the execution timing of the scan of the access point 102 by the station 101 as t1 to t8. The station 101 scans the peripheral access point 102 at a predetermined timing. T1 to t8 shown in FIG. 5 are examples of these timings. The scan is a process for the station 101 to recognize the presence of an arbitrary access point 102 in the vicinity. The station 101 receives the radio wave transmitted from the access point 102, and the station 101 receives the access point 102. Recognize the existence of By scanning, for example, a plurality of access points 102 existing in the vicinity may be recognized, or none of the access points 102 may be recognized. In the scan, the station 101 may recognize the presence of the access point 102 existing in the vicinity from the beacon 103 flying around the periphery, for example. Alternatively, the station 101 may search for a nearby access point 102 by sending a probe request in a scan, and recognize the presence of the access point 102 present in the vicinity from a reply by a probe response. Further, in the scan, the station 101 may recognize the presence of the access point 102 present in the vicinity based on both the beacon 103 and the response of the probe response to the probe request. Further, the station 101 may identify a plurality of access points 102 existing in the vicinity based on identifiers such as SSID included in the beacon 103 and the probe response, for example.

  In FIG. 5, in the scan from t1 to t7, the station 101 receives radio waves from a plurality of access points 102. However, in the period from t7 to t8, for example, it is assumed that an event has occurred in which a plurality of access points 102 existing in the entire region, such as disasters and power outages, are brought down at the same time. In this case, the down access point 102 cannot transmit the beacon 103 or return a probe response. As a result, at t8, the station 101 cannot receive radio waves from the access points 102 existing in the vicinity, and in the example shown in FIG. 5, the reception intensity of radio waves from the access points 102 existing in the vicinity is all zero. Yes. That is, when an event occurs in which a plurality of access points 102 in the area around the station 101 go down at the same time, the station 101 simultaneously and suddenly receives intensities from the plurality of access points 102 during scanning. A drop is detected.

  FIG. 6 is a graph illustrating the number of access points 102 that can receive radio waves in the station 101 when an event occurs in which a plurality of access points 102 in the vicinity of the station 101 go down all at once. In FIG. 6, the vertical axis represents the number of access points 102 that can receive radio waves at the station 101. On the horizontal axis, the execution timing of the scan of the access point 102 by the station 101 is shown as t1 to t8.

  In FIG. 6, during the period from t1 to t7, the station 101 detects a plurality of access points 102 in the vicinity thereof by scanning. However, in the period from t7 to t8, for example, it is assumed that an event has occurred in which a plurality of access points 102 existing in the entire region, such as disasters and power outages, are brought down at the same time. In this case, the down access point 102 cannot send out the beacon 103 or send back a probe response, so the station 101 cannot detect the access point 102 existing in the vicinity by scanning. As a result, the number of access points 102 existing in the vicinity detected by the station 101 at t8 decreases rapidly, and is zero in the example shown in FIG. In this way, for example, when an event that simultaneously brings down a plurality of access points 102 in a region such as a disaster or power outage occurs, the station 101 has a sudden increase in the number of access points 102 that can receive radio waves. A decrease is observed. Therefore, by monitoring the number of access points 102 detected by scanning or the reception intensity, etc., and detecting the simultaneous decrease in the number or reception intensity, a plurality of access points 102 existing in the entire region are brought down at the same time. The occurrence of an event can be detected.

  In addition, when an event occurs in which a plurality of access points 102 existing in the entire region are brought down at the same time, the station 101 cannot find the access point 102, and thus repeatedly executes scanning. However, since the access point 102 existing in the vicinity is down, there is a high possibility that a new connection destination is not found even when searching for a new connection destination by scanning. For example, when an event occurs in which a plurality of access points 102 in the entire region goes down all at once, such as a disaster or a power failure, it may take time to recover. In that case, even if the station 101 executes the scan, the access point 102 has not been recovered yet and cannot be found. Under such circumstances, it is undesirable for the access point 102 to repeatedly execute scanning, which leads to wasted power. Further, in a situation where an event that causes a plurality of access points 102 in the entire region to be brought down at the same time occurs, the means for charging the battery of the station 101 may be cut off. Therefore, there is a demand for a technology that can suppress power consumption by a wireless communication device when an event that affects the entire region, such as a disaster or a power failure, occurs.

The waste of power due to the scan under the situation where the access points 102 in the entire area are brought down at the same time is caused by, for example, the user manually turning off the wireless communication function such as the wireless LAN of the station 101. Can be prevented. However, there is no guarantee that all users will perform an operation to turn off the wireless function without forgetting, and there is a risk of running out of battery when the user notices. Therefore, in some embodiments, in order to avoid such a situation, when a situation is detected in which a plurality of access points 102 around the station 101 are down all at once, the next scan is executed. The time interval is changed to a time interval longer than normal. As a result, power consumption due to the scan of the station 101 can be suppressed.
FIG. 7 is a graph illustrating time intervals for performing a scan of access point 102, according to some embodiments. In FIG. 7, the vertical axis indicates the length of the time interval at which the station 101 scans the access point 102. The horizontal axis indicates the execution timing of the scan of the access point 102 by the station 101 as t1 to ti.

  In FIG. 7, during the period from t1 to t7, there is no event of bringing down a plurality of access points 102 existing in the entire area such as a disaster or a power failure. Therefore, the station 101 scans the access point 102 at regular time intervals during the period from t1 to t6. However, a disaster has occurred in the surrounding area where the station 101 exists during the period from t7 to t8. In such a case, the control unit 900 changes the time interval for executing the scan to a time interval longer than the normal time. For example, in the example illustrated in FIG. 7, the control unit 900 has a time interval longer than a scan time interval at a normal time (for example, a period from t1 to t7) before a disaster occurs after t8 after the disaster occurs. Scanning with As a result, power consumption due to scanning of the access point 102 can be reduced.

  Here, the time interval for executing the scan will be described in more detail. The station 101 executes a scan at a predetermined timing in order to search for a nearby access point 102. The time interval between the executions of this scan takes the following aspects into consideration, for example, in a normal situation where there are no events that cause multiple access points 102 that exist in the entire region, such as disasters or power outages, to go down all at once. May be set. That is, scanning of the access point 102 by the station 101 is a process that consumes a relatively large amount of power, and therefore it is preferable to reduce the number of scans as much as possible in order to reduce power consumption. However, if the number of scans is too small, for example, even if there is an access point 102 that can communicate more comfortably than the currently connected access point 102, the access point 102 is not recognized and cannot be used. A situation occurs. In order to prevent such a situation from occurring as much as possible, the time interval between the execution of a scan and the execution of the next scan is usually in the range of about 15 seconds to about 5 minutes (more preferably, 30 seconds to 2 minutes). Range). As described above, the time interval for executing the scan of the access point 102 is normally set to a length that suppresses battery consumption while preventing usability from being reduced as much as possible.

  On the other hand, in a situation where a plurality of access points 102 existing in the entire area such as a disaster or power outage are being brought down at the same time, even if the scan is executed at the normal time interval described above, the access point 102 May not have recovered yet. For example, when a large-scale disaster or the like occurs, it may take 1 day to several days. In such a situation, if the station 101 repeats scanning of the access point 102 at the normal time interval described above, power is wasted. Therefore, it is preferable to suppress battery consumption as much as possible even in a situation where usability is somewhat reduced, unlike in the normal situation, in a situation where a plurality of access points 102 that exist in the entire region are brought down at the same time. . Therefore, in some embodiments, in a situation where an event has occurred in which a plurality of access points 102 existing in the entire region are brought down at the same time, the scan time interval is taken into account in consideration of the time required to restore the access points 102. Is set to a longer time than normal. The time interval in such a situation may be set, for example, in the range of about 20 minutes to about 2 hours (more preferably in the range of about 30 minutes to about 1 hour).

  The time interval from the execution of the normal scan to the execution of the next scan described above is referred to as the first time interval in the following description of the embodiments. On the other hand, in the description of the following embodiment, the time interval from the execution of the scan in the situation where the event of simultaneously bringing down the plurality of access points 102 existing in the region to the next scan is executed is described. Is referred to as the second time interval. Note that the second time interval is a longer time interval than the first time interval.

  In some embodiments, when the scan time interval is changed to a second time interval that is longer than the normal first time interval, wireless communication is performed in a period until the next scan is executed. You may comprise so that a LAN function may be turned off. FIG. 8 is a diagram illustrating an example in which the wireless LAN function is turned off when an event that simultaneously brings down a plurality of access points 102 existing in a region according to some embodiments occurs. In FIG. 8, the vertical axis indicates a state where the wireless LAN function in the station 101 is on or off. On the horizontal axis, the execution timing of scanning of the access point 102 by the station 101 is shown as t1 to t8. Note that the wireless LAN function being on is, for example, a state in which power is supplied to the wireless LAN communication device provided in the station 101. On the other hand, that the wireless LAN communication device is off is a state in which power supply to the wireless LAN communication device provided in the station 101 is stopped, for example. Here, it is assumed that during the period from t7 to t8, an event has occurred in which a plurality of access points 102 existing in the entire region, such as disasters and power outages, are brought down all at once. In this case, in some embodiments, the station 101 turns off the wireless LAN function as shown at t8. Therefore, the power consumption by the wireless LAN function can be further suppressed as compared with the case where the scan time interval is simply changed to the second time interval longer than the first time interval.

  FIG. 9 is a diagram illustrating a functional block configuration of the information processing apparatus 1 according to some embodiments. The information processing apparatus 1 used as the station 101 includes a control unit 900 and a storage unit 930, for example. The control unit 900 includes functional units 910 such as a generation unit 911, a determination unit 912, and a change unit 913, for example. Furthermore, the control unit 900 includes, for example, a second determination unit 914, a third determination unit 915, a counting unit 916, a fourth determination unit 917, a fifth determination unit 918, a sixth determination unit 919, a second change unit 920, A function unit 910 such as a stop unit 921 is included. The storage unit 930 of the information processing apparatus 1 stores information 932 such as a program 931, reception intensity history information 1000 and 1400, which will be described later, and the number 10 of probe requests. The control unit 900 of the information processing apparatus 1 functions as, for example, each functional unit 910 described above by reading and executing the program 931. Details of each functional unit 910 and information 932 stored in the storage unit 930 will be described later.

  Hereinafter, referring to FIG. 10 to FIG. 13, the power consumption by the wireless LAN is reduced when an event occurs in which a plurality of access points 102 existing in the entire area is down all at once according to the first embodiment. Processing will be described.

  FIG. 10 is a diagram illustrating received strength history information 1000 according to the first embodiment. The reception intensity history information 1000 is stored in the storage unit 930 of the station 101 in one embodiment. The reception strength history information 1000 includes an access point reception strength history 1001. Each access point reception intensity history 1001 includes an identifier 1002 for identifying the access point 102 and a reception intensity history from the access point 102 identified by the identifier 1002 as a reception intensity history 1003 in time series. Storing. In the example of FIG. 10, the reception intensity history 1003 by the latest scan is registered at the right end. Therefore, in the reception intensity history 1003, the reception intensity on the left side is the radio wave reception intensity detected at an older scan timing, and the reception intensity on the right side is the reception intensity detected at a newer scan timing. It is. The identifier 1002 may be an SSID in one embodiment. In FIG. 10, the reception intensity of radio waves is expressed in dBm (1 mW is assumed to be 0 dB). In the reception intensity history 1003, “impossible to measure” indicates that the radio wave reception intensity is low and measurement is impossible.

  Next, with reference to FIG. 11, a generation process of the reception intensity history information 1000 executed by the control unit 900 of the station 101 will be described. FIG. 11 is a diagram illustrating an operation flow of the generation processing of the reception intensity history information 1000 executed by the control unit 900 of the station 101. The operation flow of FIG. 11 is implemented by, for example, reading and executing the program 931 stored in the storage unit 930 by the control unit 900 of the station 101. The operation flow of FIG. 11 starts at a predetermined timing that is determined as a timing for executing scanning of the peripheral access point 102, for example. In one embodiment, the operation flow of FIG. 11 starts after the elapse of a first time interval, which is a time interval from execution of the above-described normal scan to execution of the next scan.

  In step S <b> 1101, the control unit 900 of the station 101 performs a scan to search for nearby access points 102. In the scan, the control unit 900 of the station 101 may detect, for example, the access point 102 existing in the vicinity from the beacon 103 flying around the periphery. Alternatively, the control unit 900 may send a probe request to the peripheral access point 102 and detect the access point 102 existing in the vicinity based on the probe response received as a reply. Furthermore, the control unit 900 may detect the access point 102 present in the vicinity based on both the beacon 103 and the probe response to the probe request. For example, the beacon 103 and the probe response include the SSID as the identifier 1002 for identifying the access point 102 that has transmitted. The station 101 can identify the access point 102 existing in the vicinity by such an identifier 1002 such as an SSID.

  Subsequently, in step S1102, the control unit 900 determines whether there is a newly detected access point 102 that is not yet registered in the identifier 1002 of the received intensity history information 1000 among the access points 102 detected in the scan. Determine whether or not. If there is a newly detected access point 102 (Yes in step S1102), the flow proceeds to step S1103. On the other hand, if there is no newly detected access point 102 (No in step S1102), the flow proceeds to step S1104. In step S1103, control unit 900 registers access point reception intensity history 1001 of newly detected access point 102 in reception intensity history information 1000. In the identifier 1002 of the access point reception strength history 1001 to be registered, an identifier capable of identifying the newly detected access point 102, for example, information such as an SSID is registered. Subsequently, in step S1104, the control unit 900 adds the reception intensity of the radio wave from the access point 102 detected by the scan in step S1101 to the rightmost column of the reception intensity history 1003 of the reception intensity history information 1000. This operation flow ends. Of the access point reception intensity histories 1001 registered in the reception intensity history information 1000, a value indicating that the reception intensity of radio waves cannot be measured is registered for those in which radio waves could not be detected. In the example illustrated in FIG. 10, “unmeasurable” is used as a value indicating that the radio wave reception intensity is not measurable. The control unit 900 generates the reception intensity history information 1000 illustrated in FIG. 10 according to the operation flow of FIG. 11 described above.

  In the operation flow of FIG. 11 described above, the control unit 900 functions as, for example, the generation unit 911 in the processing from step S1101 to step S1104.

  FIG. 12 shows an operation of increasing the time interval until the next scan of neighboring access points 102 is performed when an event occurs in which the access points 102 in the region are down according to the first embodiment. It is a figure which illustrates a flow. The operation flow of FIG. 12 is implemented by, for example, reading and executing the program 931 stored in the storage unit 930 by the control unit 900 of the station 101. In one embodiment, the operation flow of FIG. 12 is performed by scanning the peripheral access points 102 according to the operation flow of FIG. 11 at the first time interval in the normal state described above, and the reception strength history information 1000 is updated. Start after.

  In step S1201, the control unit 900 of the station 101 refers to the reception intensity history information 1000. Then, in the reception intensity history information 1000, the control unit 900 receives the reception intensity history 1003 registered by the first timing scan and the reception intensity history registered by the second timing scan subsequent to the first timing. The received intensity of 1003 is compared. Note that the scan at the second timing may be the scan timing of the latest reception intensity history 1003 registered in the reception intensity history information 1000, for example. That is, for example, in FIG. 10, it may be the scan timing of the reception intensity history 1003 of T0 registered at the right end of the access point reception intensity history 1001. Also, the scan at the first timing preceding the second timing may be, for example, the scan timing immediately before the scan timing of the latest reception intensity history 1003. That is, for example, in FIG. 10, it may be the scan timing of the reception intensity history 1003 of T-1 registered second from the right end of the access point reception intensity history 1001.

  Then, the control unit 900 determines the ratio of the access points 102 that cannot be measured in the second timing scan among the access points 102 whose reception intensity registered in the first timing scan is larger than a predetermined threshold. Ask. Note that the predetermined threshold value may be set to a value at which it is determined that it is difficult to normally communicate data when the reception intensity is equal to or less than the threshold value, for example. Alternatively, in another embodiment, the threshold value may be set to a radio wave intensity that cannot be measured by a wireless communication device such as a wireless LAN provided in the station 101. Further, the measurement impossibility may be that the radio wave intensity cannot be measured by a wireless communication device such as a wireless LAN provided in the station 101, for example. And the control part 900 determines whether this calculated | required ratio is more than a predetermined | prescribed ratio. In other words, out of the access points 102 whose reception strength is equal to or higher than the threshold at the first timing, whether the percentage of the access points 102 whose reception strength becomes unmeasurable at the second timing is equal to or higher than a predetermined rate. judge.

  In step S1201, if it is less than the predetermined ratio, the flow proceeds to step S1202. In step S1202, the control unit 900 sets the time interval until the next scan of the access point 102 to the first time interval at the normal time, and the operation flow ends. On the other hand, if it is determined in step S1201 that the ratio is equal to or greater than the predetermined ratio, the flow proceeds to step S1203. In step S1203, the control unit 900 changes the time interval until the next scan of the access point 102 to the second time interval longer than the first time interval at the normal time, and the operation flow ends. . Here, the details of the first time interval and the second time interval have been described above. In one embodiment, the control unit 900 may be configured to further turn off the wireless LAN function in step S1203. Here, turning off the wireless LAN function may be, for example, stopping power supply to the wireless LAN communication device included in the station 101.

  With the operation flow of FIG. 12 described above, the control unit 900 of the station 101 causes the reception intensity at the first timing (for example, the scan executed immediately before the latest scan) to be equal to or higher than a predetermined threshold. A certain access point 102 is specified. Of the identified access points 102, the proportion of the access points 102 whose reception intensity becomes unmeasurable at the second timing (for example, the latest scan) subsequent to the first timing is a predetermined proportion. It is determined whether it is above. Here, when the ratio of the access points 102 that have fallen to an unmeasurable level from the first timing to the second timing is high, the cause is an event that causes a plurality of access points 102 in the entire region to go down all at once. There is a high possibility. Therefore, in the operation flow of FIG. 12, the control unit 900 changes the time interval from the execution of a scan to the execution of the next scan to a second time interval that is longer than the first time interval in normal times. It has changed. Therefore, for example, it is possible to prevent unnecessary power consumption by repeating scanning at the first normal time interval even though the access point 102 that has been down due to the occurrence of a disaster has not been recovered. Can do. In addition, when the time interval from the execution of the scan to the execution of the next scan is changed to the second time interval, the wireless LAN function is turned off in the period until the next scan is executed, Further power saving effect can be expected.

  In the operation flow of FIG. 12, a predetermined ratio is used to detect the occurrence of an event that causes a plurality of access points 102 in the entire region to be brought down at the same time. This is because when the access points 102 are operated using, for example, storage batteries, they continue to operate even under a power outage condition, and there is a possibility of receiving radio waves from those access points 102. Alternatively, even when an event such as a disaster or a power failure occurs that affects the entire area, there is a possibility that a weak radio wave may be received from the access point 102 that exists outside the area. Therefore, even when an event that affects the entire region such as a disaster or a power failure occurs, there is a possibility that the reception strength of all radio waves of the access point 102 in the vicinity does not become unmeasurable. For this reason, the occurrence of an event that brings down a plurality of access points 102 in the entire area at the same time is determined using a predetermined ratio. The predetermined ratio is set to such a value that it is possible to estimate the occurrence of an event that affects the entire region such as a disaster or a power failure. For example, as the predetermined ratio, a value of 30% to 100% may be used.

  In the operation flow of FIG. 12 described above, the control unit 900 functions as, for example, the determination unit 912 in the process of step S1201. Further, in the processing of step S1202 and step S1203, the control unit 900 functions as the changing unit 913, for example.

  Next, with reference to FIG. 13, a process for returning the time interval from the execution of a scan to the execution of the next scan from the second time interval to the first time interval will be described. FIG. 13 is a diagram illustrating an operation flow of the restoration process of the wireless LAN function according to the first embodiment. The operation flow in FIG. 13 is implemented by, for example, reading and executing the program 931 stored in the storage unit 930 by the control unit 900 of the station 101. In one embodiment, the operation flow of FIG. 13 shows that when the time interval from execution of a scan to execution of the next scan is set to the second time interval, Executed when two time intervals have elapsed.

  In step S <b> 1301, the control unit 900 of the station 101 performs a scan to search for an access point 102 existing in the vicinity. For example, when the wireless LAN function is turned off by the processing in step S1203 in FIG. 12, for example, scanning is performed after the wireless LAN function is turned on. Subsequently, in step S1302, the control unit 900 determines whether or not the connectable access point 102 exists in the vicinity. The access point 102 that can be connected is an access point 102 that can establish a connection by executing a series of processes such as association and authentication as described with reference to FIG. That's it.

  If there is no access point 102 that can be connected to the periphery (No in step S1302), the flow proceeds to step S1303. In step S1303, the control unit 900 sets the time interval until the next scan of the access point 102 to the second time interval longer than the first time interval at the normal time, and the operation flow ends. . In one embodiment, the control unit 900 may further be configured to turn off the wireless LAN function in step S1303. Here, turning off the wireless LAN function may be, for example, stopping power supply to the wireless LAN communication device included in the station 101.

  On the other hand, in step S1302, if there is a connectable access point 102 in the vicinity (Yes in step S1302), the flow proceeds to step S1304. In step S1304, the control unit 900 connects to the connectable access point 102 detected in step S1302, and the flow proceeds to step S1305. In step S1305, the control unit 900 changes the time interval until the next scan of the access point 102 from the second time interval to the first time interval in the normal time which is a shorter time interval, This operation flow ends.

  According to the operation flow of FIG. 13, when the control unit 900 of the station 101 executes a scan with a second time interval, if there is an access point 102 that can be connected to the periphery, the control unit 900 sets the scan time interval to the normal time. The first time interval can be returned. On the other hand, when there is no access point 102 that can be connected to the periphery, the down access point 102 may not be recovered yet. Therefore, the time interval until the next scan of the access point 102 is set again to the second time interval, and the power consumed by executing the scan is reduced.

  In the operation flow of FIG. 13 described above, the control unit 900 functions as, for example, the sixth determination unit 919 in the processing of step S1301, step S1302, and step S1304. Further, in the processing of step S1303 and step S1305, the control unit 900 functions as the second changing unit 920, for example.

  As described above, in the first embodiment, a situation in which there is a high possibility that an event that causes a plurality of access points 102 in the entire region to be brought down at the same time has occurred. Detection is performed based on a change in the reception intensity of the radio wave from 102. For example, when an event that simultaneously brings down a plurality of access points 102 existing in a region such as a disaster or power outage occurs around the station 101, the access points 102 that are down are expected to occupy a considerable proportion. On the other hand, when the access point 102 is down due to an individual cause that has occurred in each access point 102, it is unlikely that a plurality of access points 102 that are present in the region at the same time will fail. Therefore, for example, by appropriately setting the predetermined ratio in step S1201, it is possible to distinguish between a failure caused by an event that brings down a plurality of access points 102 in the region all at once and a failure caused by an individual cause. Is possible. Then, in a situation where it is estimated that an event that causes the access points 102 in the entire region to go down all at once, the time interval between the execution of the scan and the next execution of the scan is set to the first time of the normal time. A second time interval longer than the time interval is set. Therefore, it is possible to prevent frequent scanning in a situation where a plurality of access points 102 in the entire region are down, and to reduce power consumption.

  Subsequently, the second embodiment will be described with reference to FIGS. 14 and 15. In the first embodiment, the example in which the time interval until the next scan of the access point 102 is changed based on the ratio of the access points 102 where the reception intensity becomes unmeasurable has been described. However, for example, a radio wave may be temporarily shielded near the station 101 by a large truck passing near the station 101. When the scan of the access point 102 is executed in such a situation, there is a possibility that the ratio of the access point 102 where radio waves cannot be measured occupies a predetermined ratio. However, the shielding of radio waves due to the passage of a large truck near the station 101 is temporary. Therefore, in such a situation, it is not preferable to change the time interval until the next scan of the access point 102 to a longer time interval. Therefore, in the second embodiment, a further determination is made in order to more accurately determine whether or not an event has occurred in which a plurality of access points 102 existing in the entire region such as a disaster or a power outage are brought down at the same time. Do.

  FIG. 14 is a diagram illustrating received intensity history information 1400 according to the second embodiment. The reception intensity history information 1400 is stored in the storage unit 930 of the station 101 in one embodiment. Reception strength history information 1400 includes an access point reception strength history 1401. Each access point reception intensity history 1401 includes an identifier 1402 for identifying the access point 102 and a reception intensity history from the access point 102 identified by the identifier 1402 as a reception intensity history 1403 in time series. Storing. In the example of FIG. 14, the reception intensity history 1403 by the latest scan is registered at the right end. Therefore, in the reception intensity history 1403, the reception intensity on the left side is the radio wave reception intensity detected at the older scan timing, and the reception intensity on the right side is the reception intensity detected at the newer scan timing. It is. The identifier 1402 may be an SSID in one embodiment. In FIG. 14, the reception intensity of radio waves is expressed in dBm (1 mW is assumed to be 0 dB). In the reception intensity history 1403, “unmeasurable” indicates that the radio wave reception intensity is low and measurement is impossible. The reception intensity history information 1400 and the reception intensity history information 1000 are corresponding information. For example, the access point reception strength history 1401, the identifier 1402, and the reception strength history 1403 may be the same information as the access point reception strength history 1001, the identifier 1002, and the reception strength history information 1000, respectively.

  FIG. 15 shows an operation of increasing the time interval until the next scan of neighboring access points 102 is executed when an event occurs in which the access points 102 in the entire region are down according to the second embodiment. It is a figure which illustrates a flow. The operation flow of FIG. 15 is implemented by, for example, reading and executing the program 931 stored in the storage unit 930 by the control unit 900 of the station 101. In one embodiment, the operation flow of FIG. 15 is performed by scanning the peripheral access point 102 according to the operation flow of FIG. 11 at the first time interval described above, and the reception intensity history information 1000 is updated. Start after.

  In step S1501, the control unit 900 of the station 101 refers to the reception strength history information 1400. Then, in the reception intensity history information 1000, the control unit 900 receives the reception intensity history 1403 registered by the first timing scan and the reception intensity history registered by the second timing scan subsequent to the first timing. The received intensity of 1403 is compared. Note that the scan at the second timing may be, for example, the scan timing immediately before the scan timing of the latest reception intensity history 1403 registered in the reception intensity history information 1400. That is, for example, in FIG. 14, it may be the scan timing of the T-1 reception intensity history 1403 registered second from the right end of the access point reception intensity history 1401. Further, the scan at the first timing preceding the second timing may be, for example, the scan timing two times before the scan timing of the latest reception intensity history 1403. That is, for example, in FIG. 14, it may be the scan timing of the T-2 reception intensity history 1403 registered third from the right end of the access point reception intensity history 1401.

  Then, the control unit 900 determines the ratio of the access points 102 that cannot be measured in the second timing scan among the access points 102 whose reception intensity registered in the first timing scan is larger than a predetermined threshold. Ask. Note that the predetermined threshold value may be set to a value at which it is determined that it is difficult to normally communicate data when the reception intensity is equal to or less than the threshold value, for example. Alternatively, in another embodiment, the threshold value may be set to a radio wave intensity that cannot be measured by the wireless LAN communication device provided in the station 101. Further, the measurement impossibility may be, for example, that the radio wave intensity cannot be measured by the wireless LAN communication device provided in the station 101. And the control part 900 determines whether this calculated | required ratio is more than a predetermined | prescribed ratio. In other words, out of the access points 102 whose reception strength is equal to or higher than the threshold at the first timing, whether the percentage of the access points 102 whose reception strength becomes unmeasurable at the second timing is equal to or higher than a predetermined rate. judge. The predetermined ratio is set to a ratio that can estimate the occurrence of an event that affects the entire region, such as a disaster or a power failure. For example, as the predetermined ratio, a value of 30% to 100% may be used. In step S1501, when it is less than the predetermined ratio (step S1501 is No), the flow proceeds to step S1505. On the other hand, in step S1501, if the ratio is equal to or greater than the predetermined ratio (step S1501 is Yes), the flow proceeds to step S1502.

  In step S1502, the control unit 900 performs further determination on the access point 102 that becomes unmeasurable from a value larger than the threshold value from the first timing to the second timing in step S1501. The control unit 900 determines whether or not fluctuations in radio wave reception intensity from all access points 102 that cannot be measured are stable within a predetermined range in a predetermined period in the past. For example, the control unit 900 determines whether or not the reception intensity is stable in a period from the first timing to the third timing preceding the first timing by the number of predetermined timings. For example, the third timing may be a scan timing two times before the first scan timing. That is, in the example shown in FIG. 14, the third timing may be the scan timing of the T-4 reception strength history 1403 registered fifth from the right end of the access point reception strength history 1401. Then, the controller 900 determines that the difference between the maximum value and the minimum value of the reception intensity in the period from the first timing to the third timing (for example, the period from T-2 to T-4) is within a predetermined range. It is determined whether it is within the range. The predetermined range is 20 dB in the example shown in FIG.

  In step S1502, when the fluctuation is not within the predetermined range (No in step S1502), the flow proceeds to step S1505. On the other hand, in step S1502, if the fluctuation is within 20 dB (Yes in step S1502), the flow proceeds to step S1503. In step S1503, the control unit 900 determines whether the access point 102 that becomes unmeasurable from the first timing to the second timing in step S1501 is unmeasurable at the fourth timing subsequent to the second timing. Determine whether or not. The fourth timing may be, for example, a scan timing immediately after the second scan timing. That is, in the example shown in FIG. 14, the fourth timing may be the scan timing of the reception strength history 1403 of T0 registered at the rightmost end of the access point reception strength history 1401. This is a reception intensity history 1403.

  If it is determined in step S1503 that the received intensity at the subsequent scan timing is not measurable (No in step S1503), the flow proceeds to step S1505. On the other hand, when the reception intensity at the subsequent scan timing is not measurable (Yes in step S1503), the flow proceeds to step S1504. In step S1504, the control unit 900 changes the time interval until the next scan of the access point 102 to the second time interval longer than the first time interval at the normal time, and the operation flow ends. . Here, the details of the first time interval and the second time interval have been described above. In one embodiment, the control unit 900 may further be configured to turn off the wireless LAN function in step S1504. Here, turning off the wireless LAN function may be, for example, stopping power supply to the wireless LAN communication device included in the station 101. If it is determined No from step S1501 to step S1503, the flow proceeds to step S1505. In step S1505, the control unit 900 sets the time interval until the next scan of the access point 102 to the first normal time interval, and the operation flow ends.

  In the operation flow of FIG. 15 described above, the control unit 900 of the station 101 has a reception intensity at a first timing (for example, a scan executed two times before the latest scan) equal to or higher than a predetermined threshold. The access point 102 is specified. Of the identified access points 102, the percentage of the access points 102 that cannot be measured at the second timing subsequent to the first timing (for example, the scan executed immediately before the latest scan) Is greater than or equal to a predetermined ratio. Here, when the ratio of the access points 102 whose reception intensity has become unmeasurable from the first timing to the second timing is higher than a predetermined ratio, there is an event in which a plurality of access points 102 in the entire region are brought down at the same time. It is thought that it may have occurred. However, as described above, the radio wave may be temporarily shielded due to, for example, a large truck passing near the station 101. In order to reduce the possibility that such temporary shielding of radio waves may be mistaken for the occurrence of a disaster or the like, in the second embodiment, the determinations of step S1502 and step S1503 are further performed.

  In the determination in step S1502, it is determined whether the access point 102 whose reception intensity has been unmeasurable from the first timing to the subsequent second timing has shown a stable reception intensity in the past from the first timing. For example, if the reception intensity of radio waves from the access points 102 has not been stable in the past from the first timing, the cause of the decrease in the reception intensity at the access points 102 is irrelevant to the occurrence of a disaster or power outage Is likely. Therefore, when there is such an access point 102, the time interval until the next access point 102 is scanned is not changed, and is set to the first normal time interval.

  In addition, in the determination in step S1503, the access point 102 whose reception intensity has become unmeasurable from the first timing to the subsequent second timing continues even at the fourth timing following the first timing. It is determined whether measurement is impossible. For example, even if the reception intensity of the radio wave from the access point 102 cannot be measured at the first timing, it is assumed that it has recovered from the measurement inability at the subsequent fourth timing. In this case, the cause of the decrease in the reception intensity at these access points 102 is irrelevant to the occurrence of a disaster or a power outage, or even if there is a relationship, there is a high possibility that it can be recovered quickly. Therefore, when there is such an access point 102, the time interval until the next access point 102 is scanned is not changed, and is set to the first normal time interval.

  Therefore, according to the second embodiment, the access points 102 in the entire region such as disasters and power outages are more accurately compared with the first embodiment based on the determinations described in step S1502 and step S1503. It is possible to detect the occurrence of events that bring down all at once.

  In the second embodiment, when the time interval until the next scan is executed in step S1504 is changed to the second time interval, when the second time interval elapses after the scan is executed, FIG. You may comprise so that 13 operation | movement flows may be performed. According to the operation flow of FIG. 13, when the control unit 900 of the station 101 executes a scan with a second time interval, if there is an access point 102 that can be connected to the periphery, the control unit 900 sets the scan time interval to the normal time. The first time interval can be returned. On the other hand, when there is no access point 102 that can be connected to the periphery, the down access point 102 may not be recovered yet. Therefore, the time interval until the next scan of the access point 102 is set again to the second time interval, and the power consumed by executing the scan is reduced.

  In the operation flow of FIG. 15 described above, the control unit 900 functions as, for example, the determination unit 912 in the process of step S1501. In the process of step S1502, the control unit 900 functions as the second determination unit 914, for example. In the process of step S1503, the control unit 900 functions as the third determination unit 915, for example. In the processing in step S1504 and step S1505, the control unit 900 functions as the changing unit 913, for example.

  Subsequently, the third embodiment will be described with reference to FIGS. 16 and 17. In the first and second embodiments, an example has been described in which a simultaneous down of a plurality of access points 102 existing in a region such as a disaster or a power failure is detected based on the reception intensity of radio waves from the access points 102. In the third embodiment, when simultaneous down of a plurality of access points 102 existing in a region such as a disaster or a power failure is detected based on the number of probe requests 10 transmitted by other stations 101 in the vicinity An example of

  FIG. 16 shows a probe request transmitted by another station 101 that can be received by the station 101 when a plurality of access points 102 existing in the entire region such as a disaster or power outage are down all at once according to the third embodiment. It is a figure which illustrates change of several 10 of. In FIG. 16, the vertical axis represents the number of probe requests 10 that can be received by the station 101. On the horizontal axis, the execution timing of scanning of the access point 102 by the station 101 is shown as t1 to t8.

  In FIG. 16, during the period from t1 to t7, the station 101 detects a probe request transmitted by the station 101 existing in the vicinity within a certain range of increase / decrease. However, in the period between t7 and t8, for example, it is assumed that an event has occurred in which a plurality of access points 102 existing in the entire region, such as a disaster or a power outage, are brought down all at once. In this case, the down access point 102 cannot return a probe response. For this reason, the peripheral stations 101 cannot receive a probe response, cannot establish a connection, and frequently send out probe requests. As a result, the number of probe requests per unit time transmitted by the peripheral stations 101 detected at the station 101 increases rapidly (for example, t8 in FIG. 16). Therefore, in the station 101, by detecting a rapid increase in the number of probe requests 10 sent by the peripheral stations 101, it is possible to detect the occurrence of an event that causes the access points 102 in the entire region to be brought down at the same time, such as a disaster or a power failure. It is possible.

  FIG. 17 shows an operation flow for changing the time interval until the next scan of the access point 102 based on the increase in the number of probe requests 10 sent by the peripheral stations 101 according to the third embodiment. Illustrate. The operation flow in FIG. 17 is implemented by, for example, reading and executing the program 931 stored in the storage unit 930 by the control unit 900 of the station 101. In one embodiment, the operational flow of FIG. 17 begins after a scan of peripheral access points 102 is performed at a first time interval. In step S <b> 1701, the control unit 900 of the station 101 counts the number of probe requests 10 transmitted from other peripheral stations 101 and acquires the number as X. In step S1702, the controller 900 determines that the number of probe requests 10 counted in step S1701 is larger than Y, which is 10 probe requests counted in step S1701 when the operation flow of FIG. 17 was executed last time. It is determined whether or not the number has increased. In the example shown in FIG. 17, “5” is used as the predetermined number. Note that the probe request count 10 (that is, the value of Y) counted in step S1701 when the operation flow of FIG. 17 was executed last time may be stored in the storage unit 930, for example. When the operation flow of FIG. 17 is executed for the first time and Y which is the number of previous probe requests 10 is not stored in the storage unit 930, the timer A is reset and the value of X acquired in step S1701 is set to Y Is used as the value of, the process of step S1702 is executed. The case where the operation flow of FIG. 17 is executed for the first time and the storage unit 930 does not store Y which is the number of previous probe requests 10 is, for example, when the station 101 is powered on.

  In step S1702, when the value of X is larger than the value of Y by a predetermined number or more (step S1702 is Yes), the flow proceeds to step S1703. In step S1703, the control unit 900 determines whether or not the timer A that counts a predetermined period has expired. If the timer A has not expired (No in step S1703), the operation flow ends. On the other hand, if the timer A has expired (step S1703 is Yes), the flow proceeds to step S1704. In step S1704, the control unit 900 changes the time interval until the next scan of the access point 102 is executed to a second time interval longer than the first time interval in normal times. Subsequently, in step S1705, the control unit 900 resets the timer A, and this operation flow ends.

  On the other hand, in step S1702, when the value of X is not larger than the Y value by a predetermined number or more (No in step S1702), the flow proceeds to step S1706. In step S1706, the control unit 900 sets the time interval until the next scan of the access point 102 to the first time interval in the normal time. Subsequently, in step S1707, the control unit 900 resets the timer A, and the operation flow ends. Here, the details of the first time interval and the second time interval have been described above. In one embodiment, the control unit 900 may be configured to further turn off the wireless LAN function in step S1704. Here, turning off the wireless LAN function may be, for example, stopping power supply to the wireless LAN communication device included in the station 101.

  In the operation flow of FIG. 17 described above, the control unit 900 of the station 101 obtains the number of probe requests 10 transmitted from the peripheral station 101 obtained this time in step S1701 when the operation flow of FIG. Compare with the number of probe requests given. Then, it is determined whether or not the number of probe requests 10 has increased by a predetermined number or more compared to the previous time. When the number of probe requests 10 from the previous time to this time has increased by a predetermined number or more, there is a possibility that an event that causes the access points 102 in the entire region to be brought down at the same time, such as a disaster or a power failure, has occurred. However, for example, when the station 101 is used in a subway or the like, there is a situation where radio waves from the access point 102 are temporarily shielded in a section between stations. Even in such a situation, the peripheral station 101 cannot find the access point 102, and thus frequently sends a probe request. For this reason, there is a situation in which Step S1702 is determined as Yes also due to temporary shielding such as a section between subway stations. Therefore, in the operation flow of FIG. 17, whether or not the state in which the number of probe requests 10 has increased by a predetermined number or more compared to the previous time is continued in the period until the timer A expires, as determined in step S1703. Is judged. Even if there is temporary shielding such as a section between subway stations, if the shielding is canceled before the timer A expires, the flow is determined to be No in step S1702. Therefore, the scanning time interval is not changed to the second time interval. On the other hand, if the state in which the number of probe requests 10 has increased by a predetermined number or more compared to the previous time continues until timer A expires, the increase in probe requests is not due to a temporary cause. Probability is high. Therefore, in step S1704, the time interval until the next scan of the access point 102 is changed to a second time interval longer than the first time interval in the normal time. Therefore, it is possible to prevent frequent scans in a situation where a plurality of access points 102 in the region are brought down at the same time, thereby reducing power consumption.

  In the operation flow of FIG. 17 described above, the control unit 900 functions as, for example, the counting unit 916 in the process of step S1701. In the process of step S1702, the control unit 900 functions as, for example, the fourth determination unit 917. In the processing of step S1703, step S1705, and step S1707, the control unit 900 functions as the fifth determination unit 918, for example. In the processing of step S1704 and step S1706, the control unit 900 functions as the changing unit 913, for example.

  Note that the third embodiment may be implemented in combination with the first embodiment and the second embodiment. For example, instead of step S1203 in FIG. 12 and step S1504 in FIG. 15, the operation flow in FIG. 17 may be executed. In this case, for example, the number of probe requests 10 counted as X in step S1701 in FIG. 17 is the probe counted at the second timing in the operation flow in FIG. 12 or the second timing in the operation flow in FIG. The number of requests may be ten. The number of previous probe requests 10 used as Y in step S1702 in FIG. 17 is, for example, the probe request counted at the first timing in the operation flow in FIG. 12 or the first timing in the operation flow in FIG. 10 may be used.

  FIG. 18 is a diagram illustrating a hardware configuration of a computer 1800 for realizing the information processing apparatus 1 that functions as the station 101 according to some embodiments. The hardware configuration of the computer 1800 in FIG. 18 includes, for example, a processor 1801, a memory 1802, a storage device 1803, a reading device 1804, and a communication interface 1806. Furthermore, the hardware configuration of the computer 1800 in FIG. 18 also includes an input / output interface 1807 and a wireless LAN communication device 1808. Note that the processor 1801, the memory 1802, the storage device 1803, the reading device 1804, the communication interface 1806, and the input / output interface 1807 are connected to each other via a bus 1820, for example.

  The processor 1801 provides a part or all of the functions of each functional unit 910 described above by executing a program 931 describing the above-described operation flow procedure using the memory 1802. The control unit 900 of the information processing apparatus 1 is, for example, a processor 1801, and the storage unit 930 is, for example, a memory 1802, a storage device 1803, and a removable storage medium 1805. For example, the processor 1801 reads and executes a program 931 stored in the storage device 1803, thereby functioning as a functional unit 910 such as a generating unit 911, a determining unit 912, and a changing unit 913. Further, the processor 1801 reads out and executes a program 931 stored in the storage device 1803, for example, and thereby, for example, a functional unit 910 such as a second determination unit 914, a third determination unit 915, and a sixth determination unit 919. Function as. Still further, the processor 1801 reads and executes the program 931 stored in the storage device 1803, for example, thereby counting, a counting unit 916, a fourth determination unit 917, a fifth determination unit 918, a second change unit 920, and a stop. It functions as a functional unit 910 such as the unit 921. In the storage device 1803 of the computer 1800, for example, reception intensity history information 1000 and 1400 and the number of probe requests 10 are stored.

  The memory 1802 is a semiconductor memory, for example, and includes a RAM area and a ROM area. The storage device 1803 is, for example, a semiconductor memory such as a hard disk or a flash memory (SSD (Solid State Drive)), or an external storage device. The reading device 1804 accesses the removable storage medium 1805 in accordance with instructions from the processor 1801. The removable storage medium 1805 is, for example, a semiconductor device (USB memory or the like), a medium to / from which information is input / output by magnetic action (magnetic disk or the like), a medium to / from which information is input / output by optical action (CD-ROM, For example, a DVD).

  The communication interface 1806 is connected to, for example, a wireless LAN communication device 1808 and transmits / receives data via the network 1830 in accordance with instructions from the processor 1801. Further, the communication interface 1806 may be connected to a wireless communication device such as Bluetooth (registered trademark), cellular, IrDA (registered trademark), or GPS, and other communication devices. The communication interface 1806 may transmit and receive data via the network 1830 by these communication devices in accordance with instructions from the processor 1801. A wireless LAN communication device 1808 controls the wireless LAN function and performs wireless LAN communication. The input / output interface 1807 corresponds to an interface between an input device such as a microphone, a keyboard, and a mouse, and an output device such as a display device and a speaker.

The program 931 according to the embodiment is provided to the information processing apparatus 1 in the following form, for example.
(1) Installed in advance in the storage device 1803.
(2) Provided by a removable storage medium 1805.
(3) Provided from a server 1840 such as a program server.

  FIG. 19 is a diagram illustrating control for switching on and off the power supply to the wireless LAN communication device according to some embodiments including the first to third embodiments described above. The control unit 900 reads out and executes the program 931 stored in the storage unit 930, thereby executing, for example, the processing shown in the operation flow of FIGS. 12, 13, 15, and 17 described above. In these operation flows, for example, it has been described above that the wireless LAN function may be switched on or off in step S1203, step S1301, step S1303, step S1504, or step S1704. In this case, for example, as illustrated in FIG. 19, the control unit 900 controls the switch SW that switches power supply to the wireless LAN communication device 1808 with a control signal so as to switch the wireless LAN function on or off. It may be configured.

  In some embodiments including the first to third embodiments described above, the scan time interval of the access point 102 may not be constant. Thus, for example, the first time interval described above may vary between a predetermined range (eg, a range of about 15 seconds to about 5 minutes) each time a scan is performed. In other words, the scan executed at the first time interval may not be executed at a constant cycle. Similarly, the second time interval may also change between a predetermined range (eg, a range of about 20 minutes to about 2 hours) each time a scan is performed.

  In the above, several embodiments have been described. However, the embodiments according to the present invention are not limited to the above-described embodiments, but should be understood as including various modifications and alternative forms of the above-described embodiments. For example, it will be understood that various embodiments can be embodied by modifying the components without departing from the spirit and scope thereof. Further, it will be understood that various embodiments according to the present invention can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. Alternatively, various implementations according to the present invention may be made by deleting or replacing some components from all the components shown in the embodiment, or adding some components to the components shown in the embodiment. One skilled in the art will appreciate that the form may be implemented.

DESCRIPTION OF SYMBOLS 1 Information processing apparatus 100 System 101 Station 102 Access point 900 Control part 910 Function part 911 Generation part 912 Determination part 913 Change part 914 2nd determination part 915 3rd determination part 916 Count part 917 4th determination part 918 5th determination part 919 6th determination unit 920 2nd change unit 921 stop unit 930 storage unit 1800 computer 1801 processor 1802 memory 1803 storage device 1804 reader 1805 removable storage medium 1806 communication interface 1807 input / output interface 1808 wireless LAN communication device 1820 bus 1830 network 1840 server

Claims (7)

A wireless communication device for performing wireless communication;
The radio communication device receives radio waves from a plurality of neighboring access points at a plurality of timings, and the reception strength of the radio waves received at each timing of the plurality of timings is identified by an identifier included in the received radio waves A generating unit that generates reception intensity history information associated with an access point to be
In the reception strength history information, among the access points whose reception strength at the first timing is equal to or greater than a predetermined threshold, the access at which the reception strength at the second timing subsequent to the first timing becomes unmeasurable A determination unit that determines whether or not the proportion of points is equal to or greater than a predetermined proportion;
When the determination unit determines that the ratio of the access points that cannot be measured is less than a predetermined ratio, the time interval until the next reception of radio waves from the neighboring access points is the first time interval When the determination unit determines that the ratio of the access points that cannot be measured is equal to or greater than a predetermined ratio, the time interval until the next reception of radio waves from neighboring access points is set. A changing unit for changing to a second time interval longer than the first time interval;
An information processing apparatus comprising: In the access point where the reception intensity becomes unmeasurable from a value equal to or higher than a predetermined threshold from the first timing to the second timing when the determination unit determines that the ratio is equal to or higher than a predetermined ratio, A second determination unit configured to determine whether or not a difference between a maximum value and a minimum value of the reception intensity in a period from a third timing preceding the timing to the first timing is within a predetermined range; ,
The change unit determines that the determination unit is equal to or greater than a predetermined ratio, and further determines that the second determination unit determines that the variation is within a predetermined range. The information processing apparatus according to claim 1, wherein a time interval until the reception of the radio wave is changed from the first time interval to the second time interval. When the determination unit determines that it is equal to or higher than a predetermined ratio, the reception strength of the access point at which the reception strength becomes unmeasurable from a value equal to or higher than a predetermined threshold from the first timing to the second timing is A third determination unit that determines whether measurement is impossible at the fourth timing subsequent to the second timing;
The change unit determines that the determination unit is equal to or greater than a predetermined ratio, and further determines that the third determination unit cannot measure even at the fourth timing. The information processing apparatus according to claim 1, wherein a time interval until execution of reception of radio waves from a point is changed from the first time interval to the second time interval. A counting unit that counts the number of probe requests transmitted from surrounding stations at each of the plurality of timings;
Whether or not the number of probe requests at the second timing is greater than the number of probe requests at the first timing when the determination unit determines that the ratio is equal to or greater than a predetermined ratio A fourth determination unit for determining whether or not
A fifth determination unit that determines whether or not the state of increasing the predetermined number or more continues for a predetermined period or more when the fourth determination unit determines that the increase is a predetermined number or more;
Further comprising
When the determination unit determines that the determination unit is equal to or greater than a predetermined ratio, and further determines that the fifth determination unit continues for the predetermined period or longer, the change unit next receives from a neighboring access point. 4. The information processing apparatus according to claim 1, wherein a time interval until radio wave reception is performed is changed from the first time interval to the second time interval. 5. . A sixth determination unit that determines whether there is a connectable access point among the access points that have received the radio wave when performing reception of radio waves from neighboring access points at the second time interval; ,
When the sixth determination unit determines that there is an access point that can be connected, the time interval until the next reception of radio waves from neighboring access points is set from the second time interval to the first time. A second changing unit for changing to an interval;
The information processing apparatus according to any one of claims 1 to 4, further comprising:   When the change unit changes the time interval until the next reception of radio waves from neighboring access points to the second time interval, it next executes reception of radio waves from neighboring access points. The information processing apparatus according to claim 1, further comprising a stop unit that stops power supply to the wireless communication device during the period up to. A radio communication device receives radio waves from a plurality of neighboring access points at a plurality of timings, and the reception intensity of the radio waves received at each timing of the plurality of timings is identified by an identifier included in the received radio waves. Reception strength history information associated with the access point
In the reception strength history information, among the access points whose reception strength at the first timing is equal to or greater than a predetermined threshold, the access at which the reception strength at the second timing subsequent to the first timing becomes unmeasurable Determine if the percentage of points is greater than or equal to a certain percentage,
If it is determined in the determination that the proportion of the access points that cannot be measured is less than a predetermined ratio, the time interval until the next reception of radio waves from neighboring access points is set to the first time interval. Set, when it is determined that the ratio occupied by the access points that are not measurable in the determination is equal to or greater than the predetermined ratio, the time interval until the next reception of radio waves from neighboring access points, Changing to a second time interval longer than the first time interval;
A program that causes a computer to execute processing.

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