JP6255003B2 - Communication system, control method, access point, and computer program - Google Patents

Description

  The present invention relates to a technique for controlling connection between an access point and a wireless terminal.

  Conventionally, base stations for accommodating wireless communication terminals such as smartphones and mobile phones (hereinafter referred to as “wireless terminals”) in mobile communication networks such as 3G (3rd Generation) and LTE (Long Term Evolution) have been developed. I came. Furthermore, in recent years, with the spread of wireless LAN (Local Area Network) standards such as Wi-Fi (registered trademark), public access points for connecting wireless terminals having a wireless LAN communication function to the Internet are being developed. With the maintenance of such base stations and access points, an environment in which wireless terminals can always connect to the Internet is being realized. In response to such a background, several techniques related to an access point aiming at providing a better communication environment for wireless terminals have been proposed. For example, Patent Document 1 describes a technique in which a wireless terminal sets an optimal communication environment for itself by sharing log information shared between access points with the wireless terminal. In this way, with the progress of the wireless communication environment, in recent years, the provision of services using various information collected from wireless terminals has increased.

  On the other hand, there is Bluetooth (registered trademark) as one of communication means of a wireless terminal. Bluetooth (registered trademark) has advantages such as low power consumption compared to mobile communication standards, wireless LAN standards, and the like. And Bluetooth (registered trademark) has also developed a standard called BLE (Bluetooth (registered trademark) Low Energy) which realizes further power saving. Therefore, there is a need to realize a communication environment for realizing the above-described service with Bluetooth (registered trademark). The communication environment here is not an environment in which wireless terminals communicate with each other on a one-to-one basis, but a communication environment in which a plurality of wireless terminals can simultaneously communicate via an access point, such as a wireless LAN. .

JP 2004-364179 A

  However, when trying to construct a communication environment using Bluetooth (registered trademark), a mobile communication network such as 3G or LTE, a wireless LAN such as Wi-Fi (registered trademark), and the like according to the specifications of Bluetooth (registered trademark) A similar connection method (hereinafter referred to as “conventional method”) cannot be used. For this reason, in a wireless terminal accompanying movement, it may take a long time for the wireless terminal to switch the connection destination access point.

  In view of the above circumstances, an object of the present invention is to provide a technique that enables a wireless terminal to switch a connection destination access point in a sufficiently short time.

  One aspect of the present invention is a communication system including a plurality of access points that relay communication of a wireless terminal connected to its own device, wherein each of the plurality of access points is a main one of the plurality of access points. Depending on the communication quality between the connection processing unit that establishes a connection with the wireless terminal and the wireless terminal that is connected to the own device, when the own device is determined as the connection destination of the wireless terminal by the access point to be And a disconnection processing unit for disconnecting the connection with the wireless terminal.

  One aspect of the present invention is the above-described communication system, wherein the main access point acquires signal strength information indicating signal strength information of wireless terminals detected at the plurality of access points. And a connection destination selection unit that selects an access point that is a connection destination of the wireless terminal from among the plurality of access points based on the signal strength information acquired by the signal strength information acquisition unit. .

  One aspect of the present invention is the communication system described above, wherein the disconnection processing unit is not received in a past predetermined period among packets transmitted from the wireless terminal connected to the own device to the own device. The connection with the wireless terminal is disconnected when the packet loss rate indicating the packet ratio is equal to or higher than a predetermined threshold.

  One aspect of the present invention is the communication system described above, wherein the connection destination selection unit selects an access point having the strongest signal strength among access points from which the signal strength information has been acquired. Select as.

  One aspect of the present invention is a control method performed by a communication system including a plurality of access points that relay communication of a wireless terminal connected to its own device, wherein each of the plurality of access points is the plurality of access points. Between the connection processing step of establishing a connection with the wireless terminal and the wireless terminal connected to the own device when the own device is determined as a connection destination of the wireless terminal by the main access point And a disconnection process step of disconnecting the connection with the wireless terminal according to communication quality.

  One aspect of the present invention is the access point in a communication system including a plurality of access points that relay communication of a wireless terminal connected to the own device, and the access point is a main access point of the plurality of access points. When the local device is determined as a connection destination of the wireless terminal, the wireless terminal according to communication quality between the connection processing unit that establishes a connection with the wireless terminal and the wireless terminal that is connected to the local device A disconnection processing unit for disconnecting the connection.

  One aspect of the present invention is directed to a computer functioning as the access point in a communication system including a plurality of access points that relay communication of a wireless terminal connected to its own device. When the own device is determined as a connection destination of the wireless terminal by the access point, the connection processing step for establishing a connection with the wireless terminal and the communication quality between the wireless terminal connected to the own device And a disconnection processing step for disconnecting the connection with the wireless terminal.

  According to the present invention, a wireless terminal having a wireless communication function can switch a connection destination access point in a shorter time.

It is a figure explaining the outline of the communication system 10 of this embodiment. It is a functional block diagram which shows the specific example of a function structure of the access point 1 with which the communication system 10 of embodiment is provided. It is a functional block diagram which shows the specific example of a function structure of the radio | wireless terminal 2 connected to the access point 1 with which the communication system 10 of embodiment is provided. It is a sequence diagram which shows the flow of the process (disconnection process) in which the access point 1 in the communication system 10 of embodiment cut | disconnects the connection with the radio | wireless terminal 2. FIG. It is a figure which shows an example of the method by which the cutting | disconnection process part 15 determines the cutting conditions of the radio | wireless terminal 2 based on the reception condition of a confirmation packet. It is a sequence diagram which shows the flow of the process (connection process) in which the access point 1 in the communication system 10 of embodiment establishes the connection with the radio | wireless terminal 2. FIG. It is a figure which shows the specific example of the effect by which the time required for the radio | wireless terminal 2 to switch the access point 1 is shortened by the communication system 10 of embodiment.

<Outline>
In recent years, wireless terminals using short-range wireless communication standards such as Bluetooth (registered trademark) have become widespread. Although such a short-range wireless communication standard has a narrow wireless communication range, it can operate with lower power than a long-range wireless communication standard such as Wi-Fi (registered trademark) or LTE (Long Term Evolution). have. In Bluetooth (registered trademark), a standard for realizing wireless communication with lower power called BLE (Bluetooth Low Energy) is established. Therefore, if a short-range wireless communication standard capable of operating with low power such as BLE can be used for connection between the wireless terminal and the access point, a communication system more suitable for the portable terminal can be constructed.

  By the way, when it is assumed that the wireless terminal moves, the communication system is required to have a function that allows the wireless terminal to switch the access point of the connection destination according to the movement destination in order to maintain the always-on connectivity of the wireless terminal. It is done. In a mobile communication standard such as LTE, a wireless terminal can be connected simultaneously with a source and destination base station. Therefore, a wireless terminal based on such a mobile communication standard is configured to be able to seamlessly switch from a source base station to a destination base station.

  Further, according to a wireless LAN standard such as Wi-Fi (registered trademark), a wireless terminal can receive a signal transmitted by another access point in a state where a connection with the certain access point is established. Therefore, such a wireless terminal based on the wireless LAN standard is configured to be able to select and switch an access point having a high radio wave reception level based on a received signal.

  On the other hand, Bluetooth (registered trademark) has the following restrictions on specifications. First, in the long-distance wireless communication standards such as LTE and Wi-Fi (registered trademark), the wireless reception strength can be detected for the wireless terminal connected to the base station or the access point. In contrast, Bluetooth (registered trademark) cannot do this. For this reason, the access point cannot determine whether the wireless terminal connected to the own device is present at a position close to the own device or a distant location.

  One is that, in a long-distance wireless communication standard such as LTE or Wi-Fi (registered trademark), a wireless terminal can be connected to another base station or an access point even if it is connected to another base station. And the access point can be detected, but Bluetooth (registered trademark) cannot. This is because, in Bluetooth (registered trademark), the wireless terminal does not detect an access point other than the connected access point.

  Due to the above restrictions, when Bluetooth (registered trademark) is adopted as the communication method between the wireless terminal and the access point, it may take a long time for the wireless terminal to switch the access point to which it is connected. It was. In the following, an embodiment of a communication system that enables a wireless terminal to switch a connection destination access point in a sufficiently short time when using Bluetooth (registered trademark) having the above-described restrictions will be described in detail. explain.

  Note that the communication system of the embodiment described below is not realized by using a function unique to Bluetooth (registered trademark). Therefore, the configuration for the communication system of the embodiment to solve the above-described problem may be applied to any communication system using a communication standard other than Bluetooth (registered trademark). Details of the communication system of the embodiment will be described below.

<Details>
FIG. 1 is a diagram illustrating an outline of a communication system 10 according to the present embodiment. The communication system 10 includes access points 1-1 and 1-2 and a wireless terminal 2. The access points 1-1 and 1-2 relay communication of the wireless terminal 2 connected to its own device. The access points 1-1 and 1-2 are connected to the access point network 20. The access points 1-1 and 1-2 can communicate with each other via the access point network 20. The access point network 20 is connected to the Internet 30. For example, the access points 1-1 and 1-2 function as access points that provide a connection environment to the Internet 30 for the wireless terminal 2 connected to the own device.

  The wireless terminal 2 connects to the access point 1-1 or 1-2. The wireless range 40-1 represents a range in which the access point 1-1 can perform wireless communication, and the wireless range 40-2 represents a range in which the access point 1-2 can perform wireless communication. The wireless terminal 2 in the example of FIG. 1 is provided on the body of a person 100 that moves in the directions of arrows 51 and 52 within the wireless range 40-1 and the wireless range 40-2. Generally, such a terminal worn on the human body is called a wearable terminal. The wireless terminal 2 maintains the connection state to the Internet 30 by switching the connection destination access point from the access point 1-1 to the access point 1-2 as the person 100 moves. In general, such switching of access points is called roaming.

  1 illustrates an example in which the access points 1-1 and 1-2 provide a connection environment to the Internet 30 for the wireless terminal 2, the access points 1-1 and 1-2 are The wireless terminal 2 may be provided with a connection environment to a network other than the Internet 30. Also, the number of access points provided in the communication system 10 may be different from that in FIG. Hereinafter, for the sake of simplicity, the access points 1-1 and 1-2 are referred to as an access point 1 unless it is necessary to distinguish between them.

  FIG. 2 is a functional block diagram illustrating a specific example of a functional configuration of the access point 1 included in the communication system 10 according to the embodiment. The access point 1 includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and executes an access point program. The access point 1 includes a first communication unit 11, a second communication unit 12, a connection processing unit 13, a connection instruction information acquisition unit 14, a disconnection processing unit 15, a disconnection condition determination unit 16, and a connection destination selection unit by executing an access point program. 17, functions as a device including a signal strength information acquisition unit 18 and a connection instruction unit 19. Note that all or part of each function of the access point 1 may be realized using hardware such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA). The access point program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in the computer system. The access point program may be transmitted via a telecommunication line.

The first communication unit 11 is a communication interface for the access point 1 to wirelessly communicate with the wireless terminal 2.
The second communication unit 12 is a communication interface for the access point 1 to connect to the access point network 20. The second communication unit 12 communicates with other access points 1 via the access point network 20.

  The connection processing unit 13 executes connection processing for establishing a connection between the own device and the wireless terminal 2. When the connection processing unit 13 is determined by the main access point 1 (hereinafter referred to as “master AP”) of the plurality of access points included in the communication system 10 as the connection destination of the wireless terminal 2 with the own device. Then, connection with the wireless terminal 2 is established. In this case, the connection processing unit 13 identifies which wireless terminal 2 is determined as the connection destination of the own device based on the connection instruction information notified to itself. The connection instruction information is output from the connection destination selection unit 17 of the own device when the own device is the master AP, and is transmitted from another access point 1 that is the master AP when the own device is not the master AP. .

  The access point 1 operates in a first mode that operates as a master AP among a plurality of access points provided in the communication system 10 and a first mode that operates as an access point other than the master AP (hereinafter referred to as “slave AP”). It is possible to operate in any one of the two modes. For example, the access point 1 stores in advance in the storage unit setting information as to which mode the device is to operate in. The access point 1 refers to the setting information in the activation process of the own device, and activates the own device in the mode indicated by the setting information.

  The connection instruction information acquisition unit 14 is a functional unit that functions when the own device is operating as a slave AP. The connection instruction information acquisition unit 14 acquires connection instruction information transmitted from the master AP to the own apparatus. The connection instruction information acquisition unit 14 outputs the acquired connection instruction information to the connection processing unit 13.

  The disconnection processing unit 15 executes a disconnection process for disconnecting the connection between the own apparatus and the wireless terminal 2. Specifically, the disconnection processing unit 15 performs a disconnection process on the wireless terminal 2 indicated by the identification information notified from the disconnection condition determination unit 16.

  The disconnection condition determination unit 16 determines a condition (hereinafter referred to as “disconnection condition”) for disconnecting the connection of the wireless terminal 2 connected to the own apparatus. Specifically, the disconnection condition determination unit 16 determines the disconnection condition based on the communication quality between the own device and the wireless terminal 2. For example, the communication quality is determined based on the reception status of confirmation packets periodically transmitted from the wireless terminal 2. The disconnection condition determination unit 16 disconnects the wireless terminal 2 when the communication quality determined based on the reception status of the confirmation packet transmitted from a certain wireless terminal 2 is equal to or lower than a predetermined quality. It is determined that the condition is satisfied. The disconnection condition determination unit 16 notifies the disconnection processing unit 15 of the identification information of the wireless terminal 2 that satisfies the disconnection condition.

  The connection destination selection unit 17 is a functional unit that functions when the own device is operating as a master AP. The connection destination selection unit 17 determines an access point 1 (hereinafter referred to as “connection destination AP”) as the next connection destination for the wireless terminal 2 that is disconnected from the access point 1. The signal strength information is information indicating the signal strength of the wireless terminal 2 detected at the access point 1. The signal strength information includes identification information for identifying which wireless terminal 2 represents the signal strength. The signal strength information may be information indicating the signal strength itself between the access point 1 and the wireless terminal 2, or may be information indicating various amounts correlated with the signal strength. For example, the signal strength information may be represented by a received signal strength acquired as RSSI (Received Signal Strength Indicator), or may be represented by a distance between the access point 1 and the wireless terminal 2 correlated with the signal strength. Also good. In this embodiment, the RSSI (reception strength) of the received signal at the access point 1 that receives the transmission signal of the wireless terminal 2 is used as the signal strength information. Specifically, the connection destination selection unit 17 determines the connection destination AP based on the signal strength information acquired by the own device and the slave AP.

  The signal strength information acquisition unit 18 acquires signal strength information about the wireless terminal 2 detected in the own device. When the own apparatus is operating as a master AP, the signal strength information acquisition unit 18 further acquires signal strength information from the slave AP. The signal strength information acquisition unit 18 outputs the signal strength information of the own device and the slave AP to the connection destination selection unit 17. On the other hand, when the own device is operating as a slave AP, the signal strength information acquisition unit 18 transmits the signal strength information of the own device to the master AP.

  The connection instruction unit 19 transmits connection instruction information for instructing a connection with the wireless terminal 2 to the connection destination AP determined by the connection destination selection unit 17. The connection instruction unit 19 instructs the connection destination AP to connect to the wireless terminal 2 indicated by the connection instruction information by transmitting connection instruction information including identification information of the wireless terminal 2 to be connected.

  FIG. 3 is a functional block diagram illustrating a specific example of a functional configuration of the wireless terminal 2 connected to the access point 1 included in the communication system 10 according to the embodiment. The wireless terminal 2 includes a CPU, a memory, an auxiliary storage device, and the like connected by a bus, and executes a terminal program. The wireless terminal 2 functions as a device including the communication unit 21, the connection control unit 22, and the confirmation packet transmission unit 23 by executing the terminal program. All or some of the functions of the wireless terminal 2 may be realized using hardware such as an ASIC, PLD, or FPGA. The terminal program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in the computer system. The terminal program may be transmitted via a telecommunication line.

  The communication unit 21 is a communication interface for the wireless terminal 2 to wirelessly communicate with the access point 1.

  The connection control unit 22 controls establishment and disconnection of the connection with the access point 1. The connection control unit 22 transmits a connection request to the access points around the own device when the connection is disconnected by the connected access point 1 or when the own device is not connected to any access point. A connection is established with the access point 1 responding to the connection request.

  The confirmation packet transmitter 23 periodically transmits a confirmation packet to the connected access point 1 when the own device is connected to any one of the access points 1.

  FIG. 4 is a sequence diagram illustrating a flow of processing (disconnection processing) in which the access point 1 disconnects the connection with the wireless terminal 2 in the communication system 10 according to the embodiment. The process shown in the flowchart of FIG. 4 is executed in a state where the access point 1 and the wireless terminal 2 are connected. In this state, the confirmation packet transmitter 23 of the wireless terminal 2 periodically transmits a confirmation packet to the access point 1 to which the own device is connected (step S101).

  The access point 1 receives the confirmation packet transmitted from the wireless terminal 2 (step S102). The disconnection condition determination unit 16 of the access point 1 determines the disconnection condition of the wireless terminal 2 currently connected to the own apparatus based on the reception status of the confirmation packet (step S103).

FIG. 5 is a diagram illustrating an example of a method in which the disconnection processing unit 15 determines the disconnection condition of the wireless terminal 2 based on the reception status of the confirmation packet. The example of FIG. 5 is an example of determining the cutting condition based on the packet loss rate. The packet loss rate is a value indicating the ratio of unreceived packets among packets transmitted from the wireless terminal 2 connected to the own device to the own device in the past predetermined period. FIG. 5A is a timing chart showing the reception status of confirmation packets that the access point 1 periodically transmits from the wireless terminal 2. The time from t ₁ to t ₁₂ described on the time axis in FIG. 5A represents the reception timing of the confirmation packet, and the square described above each reception timing indicates whether or not the confirmation packet was received at the corresponding time. Represents. A black square indicates that a confirmation packet has been received, and a white square indicates that a confirmation packet has not been received. In the example of FIG. 5A, confirmation packets are received at times t _{1 to} t ₄ , t ₇ and t ₈ and t ₁₂ , and confirmation packets are received at times t ₅ and t ₆ and t _{9 to} t ₁₁ . Absent.

The cutting condition determination unit 16 determines the cutting condition based on the packet loss rate of the confirmation packet received in this way. For example, the disconnection condition determination unit 16 calculates the packet loss rate based on the reception status of the five latest confirmation packets. Figure 5 (B) is a diagram showing a packet loss rate calculated at time t _7. Similarly, FIG. 5C shows a packet loss rate calculated at time t ₈ , and FIG. 5D shows a packet loss rate calculated at time t ₉ . At times t ₇ and t ₈ , three of the five confirmation packets are received. Therefore, the packet loss rate at times t ₇ and t ₈ is (5-3) /5=2/5=0.4. On the other hand, at time t _9, two of the five confirmation packet is received. Therefore, the packet loss rate at time _{t 9} is (5-2) /5=3/5=0.6.

For example, when the disconnection condition in the example of FIG. 5 is “the packet loss rate is equal to or greater than the threshold value 0.5”, the disconnection condition determination unit 16 performs the times t ₇ and t ₈ when the packet loss rate is less than the threshold value. Is determined that the cutting condition is not satisfied. On the other hand, the cutting condition determining unit 16 determines that the cutting condition is satisfied at time t ₉ the packet loss rate is greater than the threshold value. In general, the packet loss rate increases as the wireless terminal 2 moves away from the access point 1. The environment in which the setting of how many recent confirmation packets are received and the threshold value of the packet loss rate are set so that the access point 1 and the wireless terminal 2 can reliably perform the disconnection process. It is good to adjust according to. The determination of the disconnection condition described above is performed for each wireless terminal 2 connected to the access point 1 based on the reception status of the confirmation packet transmitted from each wireless terminal 2.

  Returning to the description of FIG. If it is determined in step S103 that the disconnection condition is not satisfied (step S103-NO), the disconnection condition determination unit 16 returns the process to step S102, and repeatedly executes reception of the confirmation packet and determination of the disconnection condition. . On the other hand, when it is determined in step S103 that the cutting condition is satisfied, the cutting condition determining unit 16 notifies the disconnection processing unit 15 of identification information of the wireless terminal 2 that satisfies the cutting condition. The disconnection processing unit 15 executes disconnection processing for the wireless terminal 2 indicated by the identification information notified from the disconnection condition determination unit 16 (step S104). The disconnection processing unit 15 completes the disconnection process by executing a predetermined disconnection procedure with the connection control unit 22 of the wireless terminal 2 (step S105).

  Similarly, the connection control unit 22 of the wireless terminal 2 completes the disconnection process by executing a predetermined disconnection procedure with the disconnection processing unit 15 of the access point 1 (step S106). When the connection with the access point 1 is disconnected, the connection control unit 22 starts a connection request to the access point 1 around the own device (step S107). Hereinafter, this connection request is referred to as advertisement, and a signal indicating the connection request transmitted by the advertisement is referred to as advertisement signal. Hereinafter, this advertisement signal is abbreviated as ADV as necessary.

  FIG. 6 is a sequence diagram illustrating a flow of processing (connection processing) in which the access point 1 establishes a connection with the wireless terminal 2 in the communication system 10 according to the embodiment. The process shown in the flowchart of FIG. 6 is a process that continues after the disconnection of the connection between the access point 1 and the wireless terminal 2 is completed. That is, the wireless terminal 2 advertises the access point 1 around its own device at the start of the flowchart of FIG. 6 (step S201). The advertisement is continuously executed at a predetermined timing until a connection request is accepted by any access point 1.

  In the following description, connection processing when the wireless terminal 2 switches connection from the master AP to the slave AP will be described. After completing the disconnection with the wireless terminal 2, the master AP requests the slave AP to transmit signal strength information (step S202). The signal strength information acquisition unit 18 of the slave AP receives the signal strength information transmission request, and transmits the signal strength information of the wireless terminal 2 detected at that time to the master AP (step S203).

  Note that the signal strength information acquisition unit 18 may transmit the signal strength information for all the detected wireless terminals 2 or may transmit only the signal strength information of the wireless terminals 2 disconnected from the master AP. In the former case, the master AP may extract the signal strength information for the wireless terminal 2 that is the target of determining the connection destination AP, based on the identification information of the wireless terminal 2 included in the signal strength information. In the latter case, for example, the master AP transmits the transmission request including the identification information of the wireless terminal 2 that has disconnected from its own device, and the slave AP transmits the signal strength information about the wireless terminal 2 indicated by the transmission request. It may be transmitted to the master AP.

  Here, the master AP transmits a transmission request for signal strength information when the connection with the wireless terminal 2 is disconnected. This is because it is assumed that the wireless terminal 2 switches the connection from the master AP to the slave AP. Therefore, when the wireless terminal 2 switches the connection from the slave AP to another access point 1, the master AP makes a transmission request for signal strength information triggered by the reception of the disconnection notification transmitted from the switching source slave AP. Just send it. In this case, the disconnection processing unit 15 of the switching source slave AP may transmit a disconnection notification to the master AP at the timing when the connection with the wireless terminal 2 is disconnected.

  Based on the signal strength information transmitted from the plurality of slave APs, the connection destination selection unit 17 of the master AP determines the connection destination AP of the wireless terminal 2 to which the own device has disconnected (step S204). For example, the connection destination selection unit 17 determines the slave AP that receives the transmission signal of the wireless terminal 2 with the strongest strength among the plurality of slave APs as the connection destination AP. The connection destination selection unit 17 notifies the connection instruction unit 19 of the slave AP determined as the connection destination AP.

  The connection instruction unit 19 transmits connection instruction information for instructing connection to the wireless terminal 2 to which the own device has disconnected from the connection destination AP notified from the connection destination selection unit 17 (step S205). At this time, the connection instructing unit 19 transmits the identification information of the wireless terminal 2 that has been disconnected by its own device, in the connection instruction information.

  The connection instruction information acquisition unit 14 of the slave AP receives the connection instruction information transmitted from the master AP (step S206). The connection instruction information acquisition unit 14 outputs the acquired connection instruction information to the connection processing unit 13.

  In response to receiving the connection instruction information output from the connection instruction information acquisition unit 14, the connection processing unit 13 receives a connection request for the wireless terminal 2 indicated by the connection instruction information (step S207). Specifically, the connection processing unit 13 responds to the advertisement of the wireless terminal 2. When the connection processing unit 13 receives a connection request for the wireless terminal 2, the connection processing unit 13 executes a connection process for the wireless terminal 2 (step S208). The connection processing unit 13 completes the connection process by executing a predetermined connection procedure with the connection control unit 22 of the wireless terminal 2 (step S209).

  Similarly, the connection control unit 22 of the wireless terminal 2 completes the connection process by executing a predetermined disconnection procedure with the connection processing unit 13 of the slave AP (step S210). When the connection between the own device and the slave AP is established, the confirmation packet transmission unit 23 of the wireless terminal 2 starts transmitting a confirmation packet to the connected slave AP (step S211).

  In the communication system 10 of the embodiment configured as described above, the access point 1 disconnects according to the communication quality with the connected wireless terminal 2, and the access point 1 operating as the master AP is Based on the strength of the transmission signal of the wireless terminal 2 detected by the access point 1 including the device, the connection destination AP of the wireless terminal 2 is determined. By providing the access point 1 with such a function, in the communication system 10 according to the embodiment, the wireless terminal 2 can switch the access point 1 in a shorter time.

  FIG. 7 is a diagram illustrating a specific example of the effect that the time required for the wireless terminal 2 to switch the access point 1 is shortened by the communication system 10 according to the embodiment. FIG. 7A is a timing chart showing a flow of access point switching according to a conventional method (for example, a connection method such as 3G, LTE, Wi-Fi (registered trademark)). FIG. 7B is a timing chart showing the flow of access point switching by the communication system 10 of the present embodiment. As shown in FIG. 7A, in the conventional system, the switching of the access point (or base station) is not completed until the connection between the wireless terminal and the access point (or base station) times out. It may take several seconds to several tens of seconds to switch (or base station).

  On the other hand, as described in the above embodiment, the switching method of the communication system 10 of this embodiment is not a timeout type switching method like the conventional method. Therefore, in the communication system 10 according to the present embodiment, it is possible to significantly reduce the time required for the wireless terminal 2 to switch the connection destination access point 1. Specifically, in the communication system 10 of this embodiment, the waiting time for timeout (several seconds to several tens of seconds) in the conventional method is the time between the completion of the disconnection process and the transmission of the connection instruction information (T in the figure). ). Although there is a possibility that it depends on the processing performance of the access point 1 and the scale of the communication system 10, considering the processing performed by the access point 1 during the period of time T, the communication system 10 of the present embodiment has time T It can be realized in the order of 100 to tens of milliseconds.

  For the above reasons, in the communication system 10 of the embodiment, the wireless terminal 2 can connect to the connection destination in a sufficiently short time even when a communication method that is difficult to apply the conventional method such as Bluetooth (registered trademark) is used. The access point 1 can be switched. Therefore, according to the communication system 10 of the embodiment, it is possible to collect information excellent in real time from the moving wireless terminal 2. For example, when the wireless terminal 2 capable of acquiring body data is worn as a wearable terminal by a team competition player, it is possible to grasp the conditions of all the teams in real time. Further, for example, in a care facility, it is possible to grasp the health status of the care recipient in real time. In addition, when BLE is used as a communication method between the access point 1 and the wireless terminal 2, power consumption can be reduced as compared with communication methods such as 3G, LTE, and Wi-Fi (registered trademark). Therefore, a communication environment more suitable for the portable wireless terminal 2 can be constructed.

As described above, in recent years, attempts to collect information from a thing having a communication function (in the above example, a person wearing a wearable terminal) and to create a new service from the collected information have been made in IoT (Internet of Things). of Things) is attracting attention as a technical idea. The communication system 10 according to the present embodiment may be applied to a communication system that provides the wireless terminal 2 with a connection environment to a network such as the Internet 30 or may be applied to a communication system that realizes the above-described IoT. When the communication system 10 according to the present embodiment is applied to a communication system that provides a connection environment to a network, it is possible to improve the always-connectability of the wireless terminal 2. Moreover, when the communication system 10 of this embodiment is applied to the communication system which implement | achieves IoT, it becomes possible to provide a service with higher real-time property.
<Modification>

  The process in which the access point 1 operating as the master AP determines the connection destination AP of the wireless terminal 2 that has been disconnected is not necessarily performed after the connection with the wireless terminal 2 is disconnected. For example, the access point 1 may execute a process of determining a connection destination AP in parallel with the process of determining the disconnection condition of the wireless terminal 2. In this case, for example, the master AP continuously acquires signal strength information from the slave AP at a predetermined timing. The connection destination selection unit 17 detects a wireless terminal 2 that may be disconnected based on the acquired signal strength information, and sets the connection destination AP of the wireless terminal 2 for the detected wireless terminal 2 to the wireless terminal 2. It may be determined before the terminal 2 is disconnected. By providing such a configuration, the access point 1 can determine the connection destination AP at an earlier timing.

  The process in which the access point 1 operating as the master AP determines the connection destination AP does not necessarily have to be performed when the wireless terminal 2 is disconnected. For example, the master AP may determine the connection destination AP in response to a request from the slave AP. In this case, for example, the access point 1 that has received the connection request of the wireless terminal 2 transmits a connection permission request to the master AP. The master AP requests the signal strength information of the wireless terminal 2 from the access point 1 that has transmitted the connection permission request. The master AP may notify the transmission permission to the access point 1 that has transmitted the signal strength information indicating the strongest strength among the signal strengths indicated by the acquired signal strength information. In this case, if the signal strength information of the master AP shows the strongest strength, the signal permission is not notified to any access point 1 that has transmitted the signal strength information, and instead the master AP A connection with the wireless terminal 2 may be performed.

  In the above-described embodiment, the configuration in which the access point 1 has the functions of both the master AP and the slave AP has been described. However, the access point 1 is configured as a device having only the functions necessary for the master AP and the slave AP. May be.

  The master AP provided in the communication system 10 is not limited to one. A plurality of master APs may be provided in the access point 1 included in the communication system 10. In this case, each of the plurality of master APs may be configured to determine a connection destination AP for a slave AP associated in advance. In this case, the slave AP may be configured to determine whether to perform connection with the instructed wireless terminal 2 based on connection instruction information notified from a plurality of master APs. In this case, a certain master AP may be configured to function as a slave AP with respect to another master AP.

  You may make it implement | achieve the access point 1 and the radio | wireless terminal 2 in embodiment mentioned above with a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be a program for realizing a part of the above-described functions, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system. You may implement | achieve using programmable logic devices, such as FPGA (Field Programmable Gate Array).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Communication system, 20 ... Access point network, 30 ... Internet, 40-1, 40-2 ... Wireless range, 51, 52 ... Arrow which shows the moving direction of the person 100, 100 ... Person, 1, 1-1, 1 -2 ... access point, 11 ... first communication unit, 12 ... second communication unit, 13 ... connection processing unit, 14 ... connection instruction information acquisition unit, 15 ... disconnection processing unit, 16 ... disconnection condition determination unit, 17 ... connection Destination selection unit, 18 ... signal strength information acquisition unit, 19 ... connection instruction unit, 2 ... wireless terminal, 21 ... communication unit, 22 ... connection control unit, 23 ... confirmation packet transmission unit

Claims (6)

A communication system including a plurality of access points that relay communication of a wireless terminal connected to its own device,
Each of the plurality of access points is
A wireless communication unit that wirelessly communicates with the wireless terminal based on a short-range wireless communication standard;
A connection processing unit that establishes a connection with the wireless terminal when the device is determined as a connection destination of the wireless terminal by a main access point of the plurality of access points;
A disconnection processing unit that disconnects the connection with the wireless terminal according to the communication quality with the wireless terminal connected to the own device;
Equipped with a,
The main access point is
A signal strength information acquisition unit for acquiring signal strength information indicating the signal strength of the wireless terminal detected at the plurality of access points;
After the disconnection by the disconnection processing unit, based on the signal strength information acquired by the signal strength information acquisition unit, the next connection of the wireless terminal that has been disconnected from the plurality of access points A connection destination selection unit for selecting a destination access point;
Comprising
Communications system. The disconnection processing unit has a packet loss rate indicating a ratio of packets that have not been received in a past predetermined period among packets transmitted from the wireless terminal connected to the own device to the own device. Disconnect from the wireless terminal when
The communication system according to claim 1 . The connection destination selection unit selects, as an access point of the wireless terminal, an access point having the strongest signal strength among access points from which the signal strength information has been acquired.
The communication system according to claim 1 or 2 . A control method performed by a communication system including a plurality of access points that relay communication of a wireless terminal connected to its own device,
Each of the plurality of access points includes a wireless communication unit that wirelessly communicates with the wireless terminal based on a short-range wireless communication standard,
Each of the plurality of access points is
A connection processing step for establishing a connection with the wireless terminal when the device is determined as a connection destination of the wireless terminal by a main access point of the plurality of access points;
A disconnection process step for disconnecting the connection with the wireless terminal according to the communication quality with the wireless terminal connected to the own device;
I have a,
The main access point is
A signal strength information acquisition step of acquiring signal strength information indicating the signal strength of the wireless terminal detected at the plurality of access points;
After the disconnection in the disconnection processing step, based on the signal strength information acquired in the signal strength information acquisition step, the next connection of the wireless terminal that has been disconnected from the plurality of access points A connection selection step for selecting a destination access point;
Control how to have a. The access point in a communication system comprising a plurality of access points that relay communication of a wireless terminal connected to its own device,
A wireless communication unit that wirelessly communicates with the wireless terminal based on a short-range wireless communication standard;
A connection processing unit that establishes a connection with the wireless terminal when the device is determined as a connection destination of the wireless terminal by a main access point of the plurality of access points;
A disconnection processing unit that disconnects the connection with the wireless terminal according to the communication quality with the wireless terminal connected to the own device;
When the own device is the main access point,
A signal strength information acquisition unit for acquiring signal strength information indicating the signal strength of the wireless terminal detected at the plurality of access points;
After the disconnection by the disconnection processing unit, based on the signal strength information acquired by the signal strength information acquisition unit, the next connection of the wireless terminal that has been disconnected from the plurality of access points A connection destination selection unit for selecting a destination access point;
Access point with A computer program for causing a computer to function as the access point according to claim 5 .

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