Wireless terminal, information processing method, and information processing program

Abstract

The present invention suppresses the occurrence of communication interruption even when connection is switched to a wireless access point having a different segment. This wireless terminal comprises: a connection unit that is connected to a wireless access point via wireless communication; a first acquisition unit that acquires an IP address to be used in the wireless communication; a wireless communication unit that uses the acquired IP address to perform wireless communication via the wireless access point; a second acquisition unit that acquires a MAC address of a wireless device connected to the same network segment as the wireless access point; and a storage unit that stores the MAC address acquired by the second acquisition unit. The first acquisition unit reacquires an IP address to be used in the wireless communication when the MAC address of the wireless access point, which serves as the connection target of the connection unit, is not stored in the storage unit.

Description

[Technical Field]

[0001] The present invention relates to a wireless terminal, an information processing method, and an information processing program. [Background technology]

[0002] Wireless local area networks (LANs) are used in businesses, homes, etc. In wireless LANs, wireless devices such as smartphones and notebook personal computers connect to wireless access points. Once connected to a wireless access point, the wireless device obtains an IP address from a Dynamic Host Configuration Protocol (DHCP) server or similar to perform wireless communication.

[0003] Patent document 1 proposes a wireless terminal that sends a presence confirmation request message to a wireless base station at the handover destination, and when it receives a response to the presence confirmation request message, determines that the wireless base station at the handover destination and the wireless base station to which it is currently connected are in the same subnetwork. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2009 / 090953 Summary of the Invention [Problem to be solved by the invention]

[0005] The IP address system differs depending on the network segment. Therefore, if a wireless terminal connects to a wireless access point in a segment different from the wireless access point to which it is currently connected, the communication with the wireless terminal will be cut off due to the difference in the IP address system.

[0006] One aspect of the disclosed technology aims to provide a wireless terminal, an information processing method, and an information processing program that can prevent communication disconnections from occurring even when switching a connection to a wireless access point in a different segment. [Means for solving the problem]

[0007] One aspect of the disclosed technology is exemplified by the following wireless terminal: The wireless terminal includes a connection unit that connects to a wireless access point via wireless communication, a first acquisition unit that acquires an IP address to be used in the wireless communication, a wireless communication unit that performs wireless communication via the wireless access point using the acquired IP address, a second acquisition unit that acquires a MAC address of a wireless device connected to the same network segment as the wireless access point, and a storage unit that stores the MAC address acquired by the second acquisition unit, and the first acquisition unit re-acquires the IP address to be used in the wireless communication if the MAC address of the wireless access point to which the connection unit is connected is not stored in the storage unit. [Effects of the Invention]

[0008] According to the disclosed technology, it is possible to prevent communication disconnections from occurring even when switching a connection to a wireless access point in a different segment. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wireless network according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a hardware configuration of the smartphone according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of a processing block of the smartphone according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of an access point management table stored in the management database. [Figure 5]FIG. 5 is a diagram illustrating an example of a processing flow for creating an access point management table by the smartphone according to the embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of a processing flow of handover processing by the smartphone according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Embodiment> The configurations of the embodiments described below are examples, and the disclosed technology is not limited to the configurations of the embodiments. A wireless terminal according to the present embodiment has, for example, the following configuration: The wireless terminal according to the present embodiment includes a connection unit that connects to a wireless access point via wireless communication, a first acquisition unit that acquires an IP address to be used in the wireless communication, a wireless communication unit that performs wireless communication via the wireless access point using the acquired IP address, a second acquisition unit that acquires a MAC address of a wireless device connected to the same network segment as the wireless access point, and a storage unit that stores the MAC address acquired by the second acquisition unit, and the first acquisition unit re-acquires the IP address to be used in the wireless communication if the MAC address of the wireless access point to which the connection unit is connected is not stored in the storage unit.

[0011] The storage unit stores the MAC addresses of wireless devices connected to the same network segment as the wireless access point. Therefore, if the MAC address of the wireless access point to be connected is not stored in the storage unit, it can be determined that the wireless access point to be connected is connected to a different segment from the currently connected wireless access point. Therefore, by re-acquiring an IP address in such a case, the wireless terminal can prevent communication disconnections that would occur if the wireless terminal were connected to a wireless access point in a different segment.

[0012] An embodiment in which the wireless terminal is applied to a smartphone will be further described below with reference to the drawings. Fig. 1 is a diagram showing an example of the configuration of a wireless network 500 according to the embodiment. The wireless network 500 includes a router 501, multiple access points 51, 52, 53, and 54, and a smartphone 100.

[0013] The router 501 assigns an IP address in response to a request from the smartphone 100 connected via each of the access points 51, 52, 53, and 54. The router 501 includes, for example, a DHCP server. The router 501 also functions as a gateway that connects the smartphone 100 to the Internet.

[0014] The access points 51, 52, 53, and 54 are access points for a wireless LAN. A wireless terminal such as the smartphone 100 performs wireless communication via one of the access points 51, 52, 53, and 54.

[0015] The router 501 has access points 51, 52, 53, and 54 arranged in a first segment and a second segment, respectively. Access points 51 and 53 are arranged in the first segment, and access points 52 and 54 are arranged in the second segment. The IP address system of the first segment is, for example, a network address of "192.168.1.0" and a subnet mask of "255.255.255.0". The IP address system of the second segment is, for example, a network address of "192.168.2.0" and a subnet mask of "255.255.255.0". In other words, the ranges of IP addresses used in the first segment are different from those in the second segment. Therefore, wireless communication cannot be performed in the second segment using an IP address used in the first segment.

[0016] The smartphone 100 is a portable wireless terminal. For example, the smartphone 100 moves when carried by a user. The smartphone 100 switches the access point to which it is connected as it moves. In FIG. 1 , the movement of the smartphone 100 is schematically indicated by an arrow. For example, when the smartphone 100 switches the access point to which it is connected from access point 51 to access point 53, the smartphone 100 can continue communication using the IP address already set in the smartphone 100 because the access points 51 and 53 are in the same segment. On the other hand, when the smartphone 100 switches the access point to which it is connected from access point 53 to access point 54, the smartphone 100 moves to a different segment. Therefore, the smartphone 100 cannot continue communication using the IP address already set in the smartphone 100, and communication is disconnected. In this embodiment, in order to prevent such communication disconnections, the smartphone 100 employs the following configuration.

[0017] <Hardware configuration of smartphone 100> 2 is a diagram showing an example of a hardware configuration of a smartphone 100 according to an embodiment. The smartphone 100 includes a central processing unit (CPU) 101, a main memory unit 102, an auxiliary memory unit 103, and a communication unit 104. The CPU 101, the main memory unit 102, the auxiliary memory unit 103, and the communication unit 104 are interconnected by a connection bus.

[0018] The CPU 101 is also referred to as a microprocessor unit (MPU) or a processor. The CPU 101 is not limited to a single processor and may have a multiprocessor configuration. Furthermore, a single CPU 101 connected via a single socket may have a multi-core configuration. At least a portion of the processing performed by the CPU 101 may be performed by a processor other than the CPU 101, such as a dedicated processor such as a digital signal processor (DSP), a graphics processing unit (GPU), a numerical calculation processor, a vector processor, or an image processing processor. Furthermore, at least a portion of the processing performed by the CPU 101 may be performed by an integrated circuit (IC) or other digital circuit. Furthermore, at least a portion of the CPU 101 may include an analog circuit. Integrated circuits include large-scale integrated circuits (LSIs), application-specific integrated circuits (ASICs), and programmable logic devices (PLDs). PLDs include, for example, field-programmable gate arrays (FPGAs). The CPU 101 may be a combination of a processor and an integrated circuit. This combination is called, for example, a microcontroller unit (MCU), a system-on-a-chip (SoC), a system LSI, or a chipset. In the smartphone 100, the CPU 101 loads a program stored in the auxiliary storage unit 103 into a work area in the main storage unit 102 and controls peripheral devices through the execution of the program. This enables the smartphone 100 to execute processing that meets a predetermined purpose. The main storage unit 102 and the auxiliary storage unit 103 are recording media that the smartphone 100 can read.

[0019] The main storage unit 102 is exemplified as a storage unit that is directly accessed by the CPU 101. The main storage unit 102 includes a random access memory (RAM) and a read only memory (ROM).

[0020] The auxiliary storage unit 103 stores various programs and various data on a readable and writable recording medium. The auxiliary storage unit 103 is also called an external storage device. The auxiliary storage unit 103 stores an operating system (OS), various programs, various tables, etc. The OS includes a communication interface program that exchanges data with external devices connected via the communication unit 104. The external devices include, for example, other information processing devices and external storage devices connected via a computer network, etc. The auxiliary storage unit 103 may be, for example, part of a cloud system, which is a group of computers on a network.

[0021] The auxiliary storage unit 103 is, for example, an erasable programmable ROM (EPROM), a solid state drive (SSD), a hard disk drive (HDD), etc.

[0022] The communication unit 104 is an interface that connects to a wireless LAN via, for example, access points 51, 52, 53, and 54. The communication unit 104 communicates with an external device via the wireless LAN.

[0023] The smartphone 100 may further include, for example, an input unit that accepts operation instructions, etc. from a user, etc. Examples of such an input unit include input devices such as a keyboard, a pointing device, a touch panel, an acceleration sensor, or a voice input device.

[0024] The smartphone 100 may include, for example, an output unit that outputs data processed by the CPU 101 and data stored in the main memory unit 102. Examples of such an output unit include output devices such as a Liquid Crystal Display (LCD), a Plasma Display Panel (PDP), an Electroluminescence (EL) panel, and an organic EL panel.

[0025] <Processing block of smartphone 100> 3 is a diagram illustrating an example of processing blocks of a smartphone 100 according to an embodiment. The smartphone 100 includes a connection unit 11, an IP address acquisition unit 12, an AP information collection unit 13, a wireless communication unit 14, and a management database 15. The smartphone 100 executes processes as each unit of the smartphone 100, such as the connection unit 11, the IP address acquisition unit 12, the AP information collection unit 13, the wireless communication unit 14, and the management database 15, by having a CPU 101 execute a computer program deployed in an executable manner in a main storage unit 102.

[0026] The management database 15 is a database that manages information about access points. FIG. 4 is a diagram illustrating an example of an access point management table 151 stored in the management database 15. The access point management table 151 includes the following fields: "IP Address," "MAC Address," "SSID," "Threshold," and "RSSI Difference." The "IP Address" field stores the IP address of the device collected by the AP information collection unit 13. The "MAC Address" field stores the MAC address of the device collected by the AP information collection unit 13. The "SSID" field stores the Service Set Identifier (SSID) collected by the AP information collection unit 13. Note that if the device from which information is collected is not the access point 51, 52, 53, or 54, the "SSID" field may be left blank. The "Threshold" field stores a threshold value that serves as a reference for handover. The threshold value may be determined as appropriate. The "RSSI Difference" field stores a value used to determine handover. The "RSSI Difference" field stores a value that differs depending on, for example, whether the device is in the same segment as the smartphone 100.

[0027] The connection unit 11 establishes a connection with one of the access points 51, 52, 53, and 54. For example, the connection unit 11 selects and connects to an access point having the highest Received Signal Strength Indicator (RSSI) among the access points 51, 52, 53, and 54. Furthermore, the connection unit 11 performs handover to switch the access point to which the smartphone 100 is connected as the smartphone 100 moves.

[0028] The IP address acquisition unit 12 requests the router 501 to assign an IP address, and acquires the IP address from the router 501. The request for IP address assignment is made by, for example, a DHCP Discover message.

[0029] When the connection unit 11 connects to an access point, the AP information collection unit 13 makes an Address Resolution Protocol (ARP) request to collect the MAC addresses of devices connected to the same segment as the smartphone 100. The AP information collection unit 13 also collects the SSIDs and IP addresses of access points connected to the same segment. The AP information collection unit 13 stores the collected information in the access point management table 151 of the management database 15.

[0030] The wireless communication unit 14 performs wireless communication via the access point connected by the connection unit 11 using the IP address acquired by the IP address acquisition unit 12.

[0031] If the MAC address of the access point to which the connection unit 11 is to connect is not stored in the auxiliary storage unit 103, the IP address acquisition unit 12 requests the router 501 to assign an IP address, and reacquires the IP address.

[0032] <Processing flow of smartphone 100> Fig. 5 is a diagram showing an example of a processing flow for creating the access point management table 151 by the smartphone 100 according to the embodiment. The processing flow illustrated in Fig. 5 is executed periodically, for example. Hereinafter, an example of a processing flow for creating the access point management table 151 by the smartphone 100 will be described with reference to Fig. 5.

[0033] At T1, the connection unit 11 connects to one of the access points 51, 52, 53, and 54. Here, it is assumed that the connection unit 11 is connected to the access point 51. The AP information collection unit 13 acquires the SSID of the connected access point 51. The AP information collection unit 13 also acquires the SSID of the access point 53 connected to the same first segment as the access point 51.

[0034] At T2, the AP information collection unit 13 transmits an ARP request. At T3, the AP information collection unit 13 determines whether or not an ARP response to the ARP request transmitted at T2 has been received. If an ARP response has been received (YES at T3), the process proceeds to T4. If an ARP response has not been received (NO at T3), the process waits for the ARP response.

[0035] At T4, the AP information collection unit 13 registers the information acquired by the ARP response received at T3 in the access point management table 151 of the management database 15. Here, the MAC address and IP address of the access point 53 located in the same segment as the access point 51 are acquired and registered in the access point management table 151. The AP information collection unit 13 also registers the SSID acquired at T1 in the access point management table 151.

[0036] Fig. 6 is a diagram showing an example of a processing flow of handover processing by the smartphone 100 according to the embodiment. The processing in Fig. 6 illustrates processing for handing over from the access point 53 to the access point 51 or the access point 52. Hereinafter, an example of a processing flow of handover by the smartphone 100 will be described with reference to Fig. 6.

[0037] In T11, the connection unit 11 determines whether the RSSI of the access point 53 is equal to or less than the RSSI threshold registered in the access point management table 151. If the RSSI is equal to or less than the RSSI threshold (YES in T11), the process proceeds to T12. If the RSSI is not equal to the RSSI threshold, the connection unit 11 continues the connection to the currently connected access point 53 without performing handover.

[0038] In T12, the connection unit 11 selects a wireless access point with which communication is possible as a target wireless access point. The IP address acquisition unit 12 determines whether the MAC address of the wireless access point selected by the connection unit 11 is registered in the access point management table 151. If it is registered (YES in T12), the process proceeds to T13. If it is not registered (NO in T12), the process proceeds to T16. For example, if the wireless access point selected by the connection unit 11 is access point 51, it is a wireless access point in the same first segment as access point 53, so the determination in T12 is YES. Also, for example, if the wireless access point selected by the connection unit 11 is access point 52, it is a wireless access point in a second segment different from access point 53, so the determination in T12 is NO.

[0039] At T13, the IP address acquisition unit 12 adopts the first threshold, which is lower than the second threshold (see T16), as the threshold used to determine handover.

[0040] At T14, the IP address acquisition unit 12 determines whether or not the handover condition is satisfied. That is, the IP address acquisition unit 12 determines that the handover condition is satisfied if the RSSI of the access point 51 selected by the connection unit 11 as the connection target is higher than the RSSI of the currently connected access point 53 by at least a first threshold. If the condition is satisfied (YES in T14), the process proceeds to T15. If the condition is not satisfied (NO in T14), the connection unit 11 continues the connection to the access point 53 without performing handover to the access point 51.

[0041] At T15, the connection unit 11 switches the connection from the access point 53 to the access point 51 selected at T12.

[0042] At T16, the IP address acquisition unit 12 adopts a second threshold higher than the first threshold (see T13) as the threshold used to determine handover.

[0043] At T17, the IP address acquisition unit 12 determines whether or not the handover condition is satisfied. That is, the IP address acquisition unit 12 determines that the handover condition is satisfied if the RSSI of the access point 52 selected by the connection unit 11 as the connection target is higher than the RSSI of the currently connected access point 53 by at least the second threshold. If the condition is satisfied (YES in T17), the process proceeds to T15. If the condition is not satisfied (NO in T17), the connection unit 11 continues the connection to the access point 53 without performing handover to the access point 52.

[0044] At T18, the connection unit 11 switches the connection from the access point 53 to the access point 52 selected at T12. Here, the access point 52 is determined at T12 to have no MAC address registered in the access point management table 151. That is, at T18, the connection is switched to a wireless access point in the second segment different from the access point 53.

[0045] At T19, the IP address acquisition unit 12 requests the router 501 to reacquire an IP address. The smartphone 100 performs wireless communication via the access point 52 using the reacquired IP address.

[0046] <Effects of the embodiment> In the embodiment described above, when the smartphone 100 connects to a wireless access point, it collects the MAC addresses of devices in the same segment as the wireless access point and registers the collected information in the access point management table 151. If the MAC address of a wireless access point selected as a handover destination candidate is not already registered in the access point management table 151, the smartphone 100 can determine that the selected wireless access point is connected to a segment different from the currently connected wireless access point. In such a case, the smartphone 100 reacquires an IP address, thereby preventing wireless communication from being disconnected even when the smartphone 100 moves to a segment different from the current segment.

[0047] In the smartphone 100, the threshold for handover is set higher, that is, a second threshold for handover to a wireless access point in a different segment, than a first threshold for handover to a wireless access point in the same segment. By adopting such thresholds, handover to a wireless access point in a different segment is suppressed, and wireless communication of the smartphone 100 is prevented from being disconnected or temporarily stopped.

[0048] Furthermore, in this embodiment, when connecting to a wireless access point, the MAC address of a device in the same segment as the wireless access point is acquired, and this information is used to determine whether the wireless access point to be handed over is in the same segment as the currently connected wireless access point. Therefore, compared to a technique that queries the network to make this determination each time a handover occurs, this embodiment eliminates the need to wait for a response from the network, thereby reducing the network load and preventing a decrease in the processing speed for the determination.

[0049] <Modification> In the embodiment described above, the access point management table 151 registers not only MAC addresses but also IP addresses, SSIDs, and RSSI differences. Because IP addresses are registered, the smartphone 100 can determine whether the handover destination wireless access point is in the same segment as the currently connected access point, based on the IP address as well as the MAC address. However, the access point management table 151 may register only MAC addresses without registering IP addresses. The MAC address acquired by the ARP request transmitted at T2 in FIG. 5 is the MAC address of a device in the same segment as the currently connected wireless access point. Therefore, whether the handover destination wireless access point is in the same segment as the currently connected wireless access point can be determined based on whether the MAC address of the handover destination wireless access point is registered in the access point management table 151. Furthermore, the "RSSI difference" in the access point management table 151 may be managed in a management table separate from the access point management table 151 or as a setting value (constant) in a program.

[0050] When switching the connection destination to a wireless access point in a different segment (T18 in FIG. 6), the information registered in the access point management table 151 may be deleted after the switch. Then, the AP information collection unit 13 may acquire the MAC address of a device in the same segment as the wireless access point after the switch, and register it in the access point management table 151. By performing such processing, it is possible to prevent the access point management table 151 from becoming bloated, and to update the information registered in the access point management table 151 to information about a device in the same segment as the currently connected wireless access point.

[0051] The embodiments and modifications disclosed above can be combined with each other.

[0052] <<Computer-readable recording medium>> An information processing program that causes a computer or other machine or device (hereinafter referred to as a computer, etc.) to realize any of the above functions can be recorded on a computer-readable recording medium. Then, by having the computer, etc. read and execute the program from this recording medium, the function can be provided.

[0053] Here, a computer-readable recording medium refers to a recording medium that stores information such as data and programs electrically, magnetically, optically, mechanically, or chemically and that can be read by a computer. Among such recording media, those that are removable from a computer include, for example, flexible disks, magneto-optical disks, Compact Disc Read Only Memory (CD-ROM), Compact Disc Recordable (CD-R), Compact Disc Rewriteable (CD-RW), Digital Versatile Disc (DVD), Blu-ray Disc (BD), Digital Audio Tape (DAT), 8mm tape, and memory cards such as flash memory. Furthermore, examples of recording media that are fixed to a computer include hard disks and ROMs. [Explanation of symbols]

[0054] 100··Smartphone 101 CPU 102...Main memory 103...Auxiliary storage section 104··Communications Department 11 Connection 12. IP address acquisition section 13··AP Information Collection Department 14. Wireless Communication Unit 15··Management Database 151 Access point management table 500··Wireless Network 501 Router 51, 52, 53, 54 Access points

Claims

1. a connection unit for connecting to a wireless access point via wireless communication; a first acquisition unit that acquires an IP address to be used in the wireless communication; a wireless communication unit that performs wireless communication via the wireless access point using the acquired IP address; a second acquisition unit that acquires a MAC address of a wireless device connected to the same network segment as the wireless access point; a storage unit that stores the MAC address acquired by the second acquisition unit, the first acquisition unit, when a MAC address of a wireless access point to be connected by the connection unit is not stored in the storage unit, reacquires an IP address to be used in the wireless communication; The second acquisition unit When the connection unit connects to a second wireless access point whose MAC address is not stored in the storage unit, the information stored in the storage unit is erased; Obtaining a MAC address of a wireless device connected to the same segment as the second wireless access point; storing the acquired MAC address of a wireless device connected to the same segment as the second wireless access point in the storage unit; Wireless terminal.

2. The connection portion is If the MAC address of the wireless access point to be connected is stored in the storage unit, switching the connection to the wireless access point to be connected when the RSSI of the wireless access point to be connected is higher than the RSSI of the currently connected wireless access point by a first threshold or more; If the MAC address of the wireless access point to be connected is not stored in the storage unit, switching the connection to the wireless access point to be connected when the RSSI of the wireless access point to be connected is higher than the RSSI of the currently connected wireless access point by at least a second threshold value that is greater than the first threshold value. The wireless terminal of claim 1 .

3. A process of connecting to a wireless access point via wireless communication; A process of acquiring an IP address to be used in the wireless communication; Using the acquired IP address, wireless communication is performed via the wireless access point. A process of acquiring a MAC address of a wireless device connected to the same network segment as the wireless access point; A process of storing the acquired MAC address in a storage unit; a process of reacquiring an IP address to be used in the wireless communication when the MAC address of the wireless access point to be connected in the connection process is not stored in the storage unit, The process of acquiring the MAC address includes: When the computer connects to a second wireless access point whose MAC address is not stored in the storage unit, the information stored in the storage unit is deleted; Obtaining a MAC address of a wireless device connected to the same segment as the second wireless access point; storing the acquired MAC address of a wireless device connected to the same segment as the second wireless access point in the storage unit; Information processing methods.

4. A process of connecting to a wireless access point via wireless communication; A process of acquiring an IP address to be used in the wireless communication; Using the acquired IP address, wireless communication is performed via the wireless access point. A process of acquiring a MAC address of a wireless device connected to the same network segment as the wireless access point; A process of storing the acquired MAC address in a storage unit; and if the MAC address of the wireless access point selected as the connection target in the connection process is not stored in the storage unit, causing the computer performing the wireless communication to reacquire an IP address to be used in the wireless communication; The process of acquiring the MAC address includes: When the computer connects to a second wireless access point whose MAC address is not stored in the storage unit, the information stored in the storage unit is deleted; Obtaining a MAC address of a wireless device connected to the same segment as the second wireless access point; storing the acquired MAC address of a wireless device connected to the same segment as the second wireless access point in the storage unit; Information processing program.

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