JP6090753B2 - COMMUNICATION SYSTEM, DEVICE SERVER, COMMUNICATION TERMINAL, AND COMMUNICATION METHOD - Google Patents

Description

  The present invention relates to a communication system, a device server, a communication terminal, and a communication method. In particular, the present invention relates to a communication system, a device server, a communication terminal, and a communication method in a communication system including a device server connected to a device according to a predetermined connection standard and a communication terminal that communicates with the device via the device server.

  Peripheral devices (hereinafter also simply referred to as “devices”) that are used by connecting to a communication terminal with a predetermined connection standard are known. Examples of the peripheral device include a printer, a display device, and a storage device. As a connection standard for connecting a peripheral device to a communication terminal, there is a USB (Universal Serial Bus) standard, an RS-232C standard, or the like. The device can be connected not only directly to a communication terminal using a cable but also via a communication line (Patent Document 1). In this case, a device that terminates the communication line and is connected to the device according to a predetermined connection standard is referred to as a device server. That is, it can be said that the device server transfers communication between the communication terminal and the device by appropriately converting the communication data format and the connection standard.

JP 2011-242822 A

  However, when there are a plurality of wireless communication paths as candidates for the communication line, an appropriate communication path may not be selected depending on the positions of the communication terminal and the wireless base station or the communication quality of the wireless communication.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a communication system that selects a more appropriate communication path between a communication terminal and a device server.

  In order to solve the above problems, a communication system according to an aspect of the present invention includes a device server connected to a device according to a predetermined connection standard, and a communication terminal that communicates with the device via the device server. The communication terminal is a first base station that is an arbitrary radio base station, or a radio base station that is connected to the device server and is connected to the first base station via a network. A device connection capable of communicating with the device server through wireless communication with a second base station that is a base station, wherein the device server indicates information indicating the device and information indicating the second base station in association with each other. A generation unit that generates information, and a transmission unit that transmits the device connection information generated by the generation unit to the communication terminal through a first communication link established between the first base station and the communication terminal; ,Previous A relay unit that relays communication between the communication terminal and the device, wherein the communication terminal establishes the first communication link with the first base station, and the transmission unit transmits A reception unit that receives the device connection information through the first communication link, and a device communication unit that performs communication with the device, wherein the establishing unit further communicates the communication terminal with the device. And disconnecting the established first communication link and establishing a second communication link with the second base station associated with the device in the device connection information received by the receiving unit. The device communication unit communicates with the device through the second communication link by being relayed by the relay unit.

  According to this, the communication terminal establishes a communication link with a radio base station associated with a device server connected with a predetermined connection standard to a device to be connected among a plurality of radio base stations. And can communicate with the device via the established communication link.

  According to the prior art, when the communication quality of a communication link established before attempting to connect to a device is good, a new communication link is not established as described above. Therefore, the communication path for communication with the device with the communication terminal is not necessarily optimal.

  According to the present invention, even if the communication quality of the communication link established before attempting to connect to the device is good, the communication terminal can communicate with the device that is suitable for communication with the device to be connected. A new communication link is established between them. Thus, the communication system according to one embodiment of the present invention can select a more appropriate communication path between the communication terminal and the device server.

  The communication terminal further includes a radio wave strength determination unit that determines whether or not a received radio wave strength of a radio wave received from the second base station is greater than or equal to a first threshold, and the establishing unit includes the received radio wave When the radio field strength determination unit determines that the strength is not equal to or greater than the first threshold, the first communication link is prohibited from being disconnected and the second communication link is established. Further, communication between the communication terminal and the device through the first communication link may be relayed.

  According to this, when the communication terminal can perform good communication with the radio base station corresponding to the device to which the communication terminal is to connect, a new communication link is established with the radio base station. Establish. Therefore, the communication system can select a more appropriate communication path between the communication terminal and the device server, and can communicate well with the selected communication path.

  In addition, the radio field strength determination unit uses a value larger than a predetermined second threshold value used for roaming of the radio base station by the communication terminal as the first threshold value, and the received radio field strength is the first threshold value. It may be determined whether or not this is the case.

  According to this, the communication terminal uses the threshold value (second threshold value) of the received radio wave strength used for roaming as a criterion for determining whether or not the communication quality with the radio base station corresponding to the device to which the communication terminal is to connect is good. ) Use a larger threshold. In other words, when the received radio wave intensity of a radio wave received from a radio base station that newly establishes a communication link satisfies a stricter standard than that of AP switching by roaming, AP switching by communication path selection according to the present invention is performed. To. Therefore, the communication system can select a more appropriate communication path between the communication terminal and the device server, and can communicate well with the selected communication path.

  The communication terminal further includes a reception unit that receives designation information indicating a designated device designated by a user, and the establishment unit receives the device connection information when the reception unit receives the device connection information. The second communication link may be established with a radio base station associated with the designated device indicated by the accepted designation information in the device information.

  According to this, a communication terminal establishes a communication link with the radio base station corresponding to the apparatus (designated apparatus) designated by the user. The communication terminal communicates via the established communication link, thereby performing communication that becomes an appropriate communication path with the designated device.

  The device connection information indicates a device ID that can identify the device, a SSID (Service Set Identifier) and a BSSID (Basic Service Set Identifier) of a wireless communication path provided by the second base station in association with each other. When the receiving unit receives the device connection information, the establishing unit, based on the SSID and BSSID associated with the device ID included in the received device connection information, The second communication link may be established with a base station.

  According to this, when the device ID indicating the device is acquired, the communication terminal specifies the wireless communication path of the wireless base station corresponding to the device, and establishes a new communication link in the specified wireless communication path. be able to. As a result, a new communication link can be established with the radio base station.

  The ESSID of the wireless communication path provided by the first base station and the ESSID of the wireless communication path provided by the second base station may be the same.

  According to this, in a communication system configured to include a plurality of radio base stations having the same SSID, the communication terminal selects a radio base station suitable for communicating with a device from the plurality of radio base stations. It is possible to communicate with the device through a communication path via the selected wireless base station.

  The ESSID of the wireless communication path provided by the first base station and the ESSID of the wireless communication path provided by the second base station may be different from each other.

  According to this, in a communication system configured to include a plurality of radio base stations having different SSIDs, the communication terminal selects a radio base station suitable for communicating with a device from the plurality of radio base stations. It is possible to communicate with the device through a communication path via the selected wireless base station.

  Further, the predetermined connection standard may be a USB (Universal Serial Bus) standard.

  According to this, when communicating with a USB device using a device server that relays USB communication performed between the communication terminal and the USB device, the communication terminal communicates with the wireless base station corresponding to the device server. A communication link can be established between them.

  The device server may include the second base station inside the device server.

  According to this, the same effect as described above can be obtained in a radio base station having a device server function or a device server having a radio base station function.

  A communication system comprising a device server connected to a device according to a predetermined connection standard, and a communication terminal communicating with the device via the device server, wherein the communication terminal is an arbitrary radio base in the communication system Device connection information that can communicate with the device server through wireless communication with a station, and the device server indicates information indicating the device and information indicating path characteristics between the wireless base station and itself. A transmission unit that transmits the device connection information generated by the generation unit to the communication terminal, and a relay unit that relays communication between the communication terminal and the device. A terminal that establishes a wireless communication link with an arbitrary wireless base station; a receiving unit that receives the device connection information transmitted by the transmitting unit through the wireless communication link; and the device A communication unit that performs communication between the wireless communication station and the establishment unit, when the communication terminal communicates with the device, the radio base station that is most suitable based on the device connection information received by the reception unit To establish a new wireless communication link with the wireless base station, and the device communication unit is relayed by the relay unit so that the device communicates with the device through the newly established wireless communication link. The communication may be performed.

  According to this, when a network device such as a router exists on the LAN connecting the wireless base stations, communication can be performed using a communication path through the optimal network device via which the wireless base station is connected.

  A communication system comprising a device server connected to a device according to a predetermined connection standard and a communication terminal communicating with the device via the device server, wherein the communication terminal is an arbitrary radio base station. Through wireless communication with one base station or a second base station which is a wireless base station connected to the device server via a wireless communication line and connected to the first base station via a network The generation unit is communicable with the device server, and the device server generates device connection information indicating information indicating the device and information indicating a radio base station in the communication system, and the generation unit A transmission unit that transmits the device connection information generated by the communication terminal to the communication terminal, and a relay unit that relays communication between the communication terminal and the device. An establishment unit that establishes a wireless communication link with each other, a reception unit that receives the device connection information transmitted by the transmission unit through the wireless communication link, and a device communication unit that performs communication with the device The establishment unit further establishes a wireless communication link with the first base station, which is a device excluding the second base station, when the communication terminal communicates with the device, The device communication unit may perform communication with the device through the newly established wireless communication link by being relayed by the relay unit.

  According to this, when the device server is connected to the wireless base station by wireless communication, an appropriate one is selected from the communication paths in which the wireless communication is not performed, and wireless communication is performed in the selected communication path. It can be performed.

  The device server according to one aspect of the present invention is a device server connected to a device according to a predetermined connection standard, and a communication terminal that communicates with the device via the device server is an arbitrary radio base station. Can communicate with the device server through a certain first base station or a second base station that is a wireless base station connected to the device server and connected to the first base station via a network The device server generates a device connection information indicating the information indicating the device and the information indicating the second base station in association with each other, and the device connection information generated by the generation unit. A transmission unit that transmits to the communication terminal through a first communication link established between the first base station and the communication terminal, and a relay unit that relays communication between the communication terminal and the device. Prepare.

  Thereby, there exists an effect similar to said communication system.

  A communication terminal according to an aspect of the present invention is a communication terminal that communicates with the device via a device server connected to the device with a predetermined connection standard, and the communication terminal is an arbitrary radio base station. The device through wireless communication with a first base station or a wireless base station connected to the device server and a wireless base station connected to the first base station via a network The communication terminal is capable of communicating with a server, and the communication terminal includes an establishing unit for establishing the first communication link with the first base station, information indicating the device, and information indicating the second base station. A receiving unit that receives the device connection information shown in association with the first communication link; and a device communication unit that performs communication with the device, wherein the establishing unit is further configured so that the communication terminal is the device. Before establishing when communicating with Disconnecting the first communication link and establishing a second communication link with the second base station associated with the device in the device connection information received by the receiving unit, the device communication unit, By being relayed by the relay unit, communication with the device through the second communication link is performed.

  Thereby, there exists an effect similar to said communication system.

  A communication method according to an aspect of the present invention is a communication method in a communication system including a device server connected to a device according to a predetermined connection standard and a communication terminal that communicates with the device via the device server. The communication terminal is a first base station which is an arbitrary radio base station, or a radio base station connected to the device server and connected to the first base station via a network. Communication with the device server is possible through wireless communication with a certain second base station, and the communication method generates device connection information indicating information indicating the device and information indicating the second base station in association with each other. And a transmission step of transmitting the device connection information generated in the generation step to the communication terminal through a first communication link established between the first base station and the communication terminal. A relay step for relaying communication between the communication terminal and the device; an establishment step for establishing the first communication link with the first base station; and the device connection transmitted in the transmission step. A reception step of receiving information through the first communication link, and a device communication step of performing communication with the device, wherein the establishing step further includes the communication terminal communicating with the device, Disconnect the established first communication link, and establish the second communication link with the second base station associated with the device in the device connection information received in the receiving step, In the device communication step, communication with the device through the second communication link is performed by being relayed by the relay unit.

  Thereby, there exists an effect similar to said communication system.

  Note that the present invention can be realized not only as an apparatus but also as a method using steps as processing units constituting the apparatus, as a program for causing a computer to execute the steps, or as a computer read recording the program. It can also be realized as a possible recording medium such as a CD-ROM, or as information, data or a signal indicating the program. These programs, information, data, and signals may be distributed via a communication network such as the Internet.

  The communication system according to the present invention can select a more appropriate communication path between the communication terminal and the device server.

FIG. 1 is a network configuration diagram of the communication system according to the first embodiment. FIG. 2 is a hardware configuration diagram of the device server according to the first embodiment. FIG. 3 is a hardware configuration diagram of the communication terminal according to the first embodiment. FIG. 4 is a hardware configuration diagram of the radio base station according to the first embodiment. FIG. 5 is a functional block diagram of the communication system according to the first embodiment. FIG. 6 is an explanatory diagram illustrating a first example of device connection information according to the first embodiment. FIG. 7 is a flowchart showing processing of the communication terminal according to Embodiment 1. FIG. 8 is a flowchart showing processing of the device server according to the first embodiment. FIG. 9 is a sequence diagram of the communication system according to the first embodiment. FIG. 10A is an explanatory diagram of a communication path between a device server and a communication terminal in the prior art. FIG. 10B is an explanatory diagram of a communication path between the device server and the communication terminal according to Embodiment 1. FIG. 11 is a network configuration diagram of a communication system according to the first modification of the first embodiment. FIG. 12A is an explanatory diagram illustrating an example of device connection information created from device connection information acquired from a plurality of radio base stations according to the first modification of the first embodiment. FIG. 12B is a network configuration diagram of a communication system according to Modification 2 of Embodiment 1. FIG. 12C is an explanatory diagram illustrating an example of device connection information created from device connection information acquired from a plurality of radio base stations according to Modification 2 of Embodiment 1. FIG. 13 is a network configuration diagram of the communication system according to the second embodiment. FIG. 14 is an explanatory diagram showing an example of device connection information created from device connection information acquired from a plurality of radio base stations according to the second embodiment. FIG. 15 is a network configuration diagram of a communication system according to the third embodiment.

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

  Each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are described as optional constituent elements that constitute a more preferable embodiment.

  In addition, the same code | symbol is attached | subjected to the same component and description may be abbreviate | omitted.

(Embodiment 1)
In the present embodiment, a communication system that selects a more appropriate communication path between a communication terminal and a device server will be described.

  FIG. 1 is a network configuration diagram of a communication system 50 according to the present embodiment.

  As illustrated in FIG. 1, the communication system 50 includes a device server 11, a communication terminal 15, radio base stations 31 and 32, a device 35, LANs 40 and 41, and a connection cable 42.

  The device server 11 is connected to the device 35 by a connection cable 42. The device server 11 is connected to the radio base station 32 via a LAN 41 (Local Area Network). The device server 11 relays communication between the communication terminal 15 and the device 35 through the LAN 41. That is, the device server 11 receives the communication packet on the LAN related to the communication from the communication terminal 15, extracts the communication data for the device 35 included in the received communication packet, and sends the extracted communication data to the device 35. Transmit according to the connection standard. The device server 11 receives communication data from the device 35 according to a predetermined connection standard, includes the received communication data in a communication packet on the LAN, and transmits the communication data to the communication terminal 15 through the LAN 41. In this way, the device server 11 relays transmission / reception of communication data according to a predetermined connection standard between the communication terminal 15 and the device 35. Note that “relay” refers to data communication on a LAN and data communication in accordance with a predetermined connection standard being converted from one to the other and transferring the communication data as described above.

  The predetermined connection standard is a connection standard different from the LAN, and can be, for example, the USB standard or the RS232C standard. Hereinafter, a case where the predetermined connection standard is the USB standard (hereinafter also simply referred to as “USB”) will be described. However, the above is merely an example, and the present invention is not limited to the USB standard. Note that communication conforming to the USB standard is also referred to as USB communication.

  The communication terminal 15 is a wireless communication terminal having a wireless communication interface. The communication terminal 15 establishes a communication link 25 with the radio base station 31 or establishes a communication link 26 with the radio base station 32 to perform radio communication. The communication terminal 15 can communicate with other communication devices connected to the LAN 40 via the communication link 25 and the radio base station 31, or via the communication link 26 and the radio base station 32.

  Further, the communication terminal 15 can communicate with the device server 11 through the communication link, the radio base station, and the LAN 41 as described above. The device server 11 relays the USB communication so that the communication terminal 15 can perform USB communication with the device 35.

  The radio base station 31 is a radio base station (access point) having a radio communication interface. The radio base station 31 establishes a communication link 25 with the communication terminal 15 existing in the radio communicable area and performs radio communication. The communication link 25 is established in a logical communication path 21 (hereinafter, also simply referred to as “communication path”) for wireless communication. The communication path is specified by attribute information including an SSID (Service Set Indentifier) that is an identifier of a network used for wireless communication and a BSSID (Basic Service Set Indentifier). In the attribute information 21A of the communication path 21 of the radio base station 31, the SSID is “SS1” and the BSSID is “BS1”. The SSID may be written as a character string (for example, “abc01”) made up of alphabetic characters, numbers, or symbols. The BSSID is a numerical value expressed by 48 bits (a numerical value expressed by a 12-digit hexadecimal number) and may be expressed as “00: 00: 01: 00: 11: aa”. Note that the wireless communication is realized by a wireless LAN that conforms to, for example, the IEEE 802.11a, b, g, and n standards. The radio base station 31 corresponds to the first base station.

  The radio base station 31 is connected to the LAN 40 and transfers a communication frame (communication packet) exchanged between the communication terminal 15 and another communication apparatus connected to the LAN 40. Specifically, when receiving a communication frame whose destination is a terminal connected to the LAN 40 from the communication terminal 15, the radio base station 31 transfers the communication frame to the LAN 40. Further, upon receiving a communication frame destined for the communication terminal 15 from a terminal connected to the LAN 40, the radio base station 31 transfers the communication frame to the communication terminal 15.

  Similar to the radio base station 31, the radio base station 32 is a radio base station apparatus having a radio communication interface. The radio base station 32 establishes a communication link 26 with the communication terminal 15 and performs radio communication. In the attribute information 22A of the communication path 22 of the radio base station 32, the SSID is “SS1” and the BSSID is “BS2”. That is, the communication path 21 of the radio base station 31 and the communication path 22 of the radio base station 32 have the same SSID and different BSSIDs. The radio base station 32 corresponds to a second base station.

  The device 35 is a device having a predetermined function that is connected to the device server 11 by the connection cable 42. The device 35 is, for example, a printer, a display device, or a storage device. When the device server 11 relays USB communication, the device 35 can perform USB communication with the communication terminal 15.

  The LAN 40 is a communication network (local area network) used for communication between the radio base station 31 and the radio base station 32. Note that the LAN 40 is realized by a wired LAN conforming to, for example, the IEEE 802.3 standard.

  The LAN 41 is a communication network used for communication between the radio base station 32 and the device server 11. Note that the LAN 40 is realized by a wired LAN conforming to, for example, the IEEE 802.3 standard.

  The connection cable 42 is a cable used for communication between the device server 11 and the device 35 according to a predetermined connection standard. The type of cable is generally determined in advance by a predetermined connection standard. If the predetermined connection standard is the USB standard, the connection cable 42 is a USB cable.

  1 except for the device server 11 and the communication terminal 15 need only have the same functions as those in the prior art.

  In FIG. 1, a communication system 50 including two radio base stations is shown. From a radio base station 31 not connected to the device server 11 to a radio base station 32 connected to the device server 11, a communication terminal A description will be given of switching of the communication link 15 (also referred to as “AP switching”). Here, the communication system 50 may include three or more radio base stations. In FIG. 1, the device server 11 is connected to one of the two radio base stations, but the device server may be connected to each of the two radio base stations. Furthermore, when there are three or more radio base stations, the device server 11 may be connected to some or all of them. In any of the above cases, the radio base station in which the communication terminal 15 has established the communication link before the AP switching is regarded as the radio base station 31, and the radio base station in which the communication terminal 15 establishes the communication link after the AP switching. The station may be regarded as the radio base station 32.

  FIG. 2 is a hardware configuration diagram of the device server 11 according to the present embodiment.

  As shown in FIG. 2, the device server 11 includes a CPU 101 (Central Processing Unit), a ROM 102 (Read Only Memory), a RAM 103 (Random Access Memory), a storage device 104, a NIC 105 (Network Interface Card), and the like. USB-IF 106 (Universal Serial Bus-Interface).

  The CPU 101 is a processor that executes a control program stored in the ROM 102.

  The ROM 102 is a read-only storage area that holds a control program and the like.

  The RAM 103 is a volatile storage area used as a work area used when the CPU 101 executes a control program.

  The storage device 104 is a non-volatile storage area that holds a control program or image data.

  The NIC 105 is a communication interface that transmits communication data to the LAN 40 or the like or receives communication data from the LAN 40 or the like. The NIC 105 may be a wired LAN interface that conforms to the IEEE 802.3 standard or the like, or may be a wireless LAN interface that conforms to the IEEE 802.11a, b, g, or n standard.

  The USB-IF 106 is a communication interface that transmits data to the device 35 according to the USB standard or receives data from the device 35 according to the USB standard. The USB-IF 106 is an example of a communication interface that performs communication corresponding to a predetermined connection standard.

  FIG. 3 is a hardware configuration diagram of the communication terminal according to the present embodiment.

  As illustrated in FIG. 3, the communication terminal 15 includes a CPU 151, a ROM 152, a RAM 153, a storage device 154, and a WNIC 155. Of the hardware components of the communication terminal 15, the same components as those in the device server 11 have the same names, and a detailed description thereof is omitted.

  The WNIC 155 is a wireless communication interface that performs wireless communication with the communication terminal 15. The WNIC 155 is a wireless LAN communication interface that conforms to, for example, the IEEE 802.11a, b, g, and n standards.

  FIG. 4 is a hardware configuration diagram of the radio base station according to the present embodiment.

  As illustrated in FIG. 4, the radio base station 31 includes a CPU 301, a ROM 302, a RAM 303, a storage device 304, a WNIC 305, and a NIC 306. Of the hardware components of the radio base station 31, the same components as those in the device server 11 or the communication terminal 15 are given the same names, and detailed description thereof is omitted. Note that the radio base station 32 has the same hardware configuration as that of the radio base station 31, and therefore a detailed description of the radio base station 32 is omitted.

  Note that the radio base station 32 may be provided inside the device server 11. In that case, hardware components common to the radio base station 32 and the device server 11 are shared by both. Similarly to the above, the radio base station 31 may include the device server 11 inside the radio base station 31.

  FIG. 5 is a functional block diagram of the communication system according to the present embodiment.

  As shown in FIG. 5, the communication system 50 includes a device server 11 and a communication terminal 15.

  First, the device server 11 will be described. The device server 11 includes a generation unit 111, a transmission unit 112, and a relay unit 113.

  The generation unit 111 generates device connection information that indicates information indicating the device 35 and information indicating the radio base station 32 in association with each other. Specifically, the generation unit 111 includes the device ID of the device 35 to which the device server 11 is connected by the connection cable 42, and the attribute information 22A of the communication path 22 of the wireless base station 32 to which the device server 11 is connected by the LAN 41. Is generated in association with each other. In other words, in the device connection information, a radio base station suitable for passing through when the communication terminal 15 performs USB communication with the device is associated with each device. The device ID or attribute information 22A may be acquired from the device 35 or the radio base station 32, or may be set in advance by a user or the like. The “appropriate radio base station” may be, for example, a radio base station whose communication path passing through the radio base station is the shortest path. In addition, it is good also as a radio base station in which the cost concerning communication becomes the minimum in consideration of the type of communication link. The generation unit 111 is realized by the CPU 101, the ROM 102, the RAM 103, the storage device 104, and the like. The device connection information will be described in detail later.

  The transmission unit 112 transmits the device connection information generated by the generation unit 111 to the communication terminal 15. The transmitted device connection information is received by the communication terminal 15 through the communication link 25 established between the radio base station 31 and the communication terminal 15. Specifically, in a state where the communication terminal 15 has established the communication link 25 with the radio base station 31, the transmission unit 112 transmits the device connection information generated by the generation unit 111. The transmitted device connection information is delivered to the communication terminal 15 via the LAN 41, the wireless base station 32, the LAN 40, and the wireless base station 31 in this order. The transmission unit 112 is realized by the CPU 101, the ROM 102, the RAM 103, the storage device 104, the NIC 105, and the like.

  The relay unit 113 relays communication between the communication terminal 15 and the device 35 performed through the communication link 26 established between the radio base station 32 and the communication terminal 15. Specifically, the relay unit 113 relays USB communication between the communication terminal 15 and the device 35 in a state where the communication terminal 15 has established the communication link 26 with the wireless base station 32. That is, the communication data for the device 35 included in the communication packet received from the communication terminal 15 through the LAN 41 is extracted, and the extracted communication data is transmitted to the device 35 according to the USB standard. The device server 11 receives communication data from the device 35 according to the USB standard, and transmits a communication packet including the received communication data to the communication terminal 15 through the LAN 41. The relay unit 113 is realized by the CPU 101, the ROM 102, the RAM 103, the storage device 104, the USB-IF 106, and the like.

  Next, the communication terminal 15 will be described. The communication terminal 15 includes an establishing unit 161, a receiving unit 162, a device communication unit 163, a radio wave intensity determining unit 164, and a receiving unit 165.

  First, the establishing unit 161 establishes a communication link 25 with the radio base station 31 on the communication path 21 specified by the attribute information 21A. Specifically, the establishment unit 161 performs communication (Authentication) for authentication and communication (Association) for establishing a connection with the radio base station 31 to establish a communication with the radio base station 31. A communication link 25 is established.

  In addition, when the communication terminal 15 connects to the device 35, the establishing unit 161 disconnects the established communication link 25, and the radio base station associated with the device 35 in the device connection information received by the receiving unit 162 A communication link 26 is established with Specifically, when the receiving unit 162 receives the device connection information, the establishing unit 161 performs communication for releasing connection (Disassociation) and communication for releasing authentication between the wireless base station 31 (Deauthentication). ), The communication link 25 is disconnected. Thereafter, in order to establish a connection with the device 35 described in the received device connection information, an attribute is obtained with the radio base station 32 that is a radio base station associated with the device 35 in the device connection information. A communication link 26 is established on the communication path 22 specified by the information 22A. The procedure for establishing the communication link 26 with the radio base station 32 is the same as the procedure for establishing the communication link 25 with the radio base station 31.

  The reception unit 162 receives the device connection information transmitted by the transmission unit 112 of the device server 11 through the communication link 25. The device connection information is associated with a wireless base station suitable for passing through the device when the communication terminal 15 performs USB communication with the device.

  The device communication unit 163 performs USB communication with the device 35 via the wireless base station 32 and the device server 11. The device communication unit 163 performs communication with the device 35 through the communication link 26 by being relayed by the relay unit 113.

  The radio wave strength determination unit 164 determines whether or not the received radio wave strength of the radio wave received from the radio base station 32 is greater than or equal to the first threshold. Specifically, the radio field strength determination unit 164 acquires the received radio field strength of the radio wave received from the wireless base station 32 by the WNIC 155 of the communication terminal 15. Then, it is determined whether or not the acquired received radio wave intensity is equal to or higher than the first threshold value. When it is determined that the received radio wave intensity is not equal to or higher than the first threshold value, switching to the radio base station by the establishing unit 161 is performed. Disconnecting and establishing the communication link 26 may be prohibited.

  In addition, the communication terminal conventionally has a second threshold value that is a threshold value for switching a radio base station with which a communication link is established among a plurality of radio base stations. The second threshold is, for example, a threshold used for so-called roaming. That is, when the communication terminal moves from the vicinity of the wireless base station A to the vicinity of the adjacent wireless base station, the received radio wave intensity from the wireless base station A falls below the second threshold, or the wireless terminal When the received radio wave intensity from the base station B exceeds the second threshold, the communication terminal switches the radio base station.

  The radio wave intensity determination unit 164 may set a value larger than the second threshold as the first threshold (that is, first threshold> second threshold). That is, the reference of the received radio wave intensity may be set more strictly than in the case of roaming. In this way, it is possible to perform switching after determining that sufficiently good communication is possible in the radio base station after switching.

  The accepting unit 165 accepts designation information indicating a designated device designated by the user. When the reception unit 165 receives the designation information, when the reception unit 162 receives the device connection information, the reception unit 162 communicates with the designated device indicated by the received designation information between the wireless base station associated with the device information. The communication link may be established with

  FIG. 6 is an explanatory diagram showing a first example of device connection information according to the present embodiment.

  The device connection information T601 shown in FIG. 6 includes a device ID, an SSID, and a BSSID.

  The device ID is an identifier that can uniquely identify the device 35.

  The SSID is an SSID of a radio base station that is suitable for passing through when the device 35 specified by the device ID and the communication terminal 15 perform USB communication.

  The BSSID is a BSSID of a radio base station that is suitable for passing through when the device 35 specified by the device ID and the communication terminal 15 perform USB communication.

  In the device connection information T601, the device 35 specified by the device ID corresponds to the SSID and BSSID included in the attribute information 22A of the communication path 22 of the wireless base station 32 suitable for communicating with the device 35. Shown with it.

  In the device connection information T601, the SSID included in the attribute information 22A of the communication path 22 of the wireless base station 32 connected to the device 35 identified by the device ID and the device server 11 connected to the device 35 via the LAN 41. A BSSID may be associated.

  7 and 8 are flowcharts of the communication terminal and the device server according to the present embodiment, respectively. FIG. 9 is a sequence diagram of the communication system according to the present embodiment. The flow of communication of the communication system according to the present embodiment will be described with reference to these. In these drawings, the radio base station 31 may be described as AP1, and the radio base station 32 may be described as AP2.

  FIG. 7 is a flowchart showing processing of the communication terminal according to the present embodiment.

  In step S <b> 701, the establishing unit 161 establishes the communication link 25 with the radio base station 31. For example, when the communication terminal 15 is located closer to the radio base station 31 than the radio base station 32, the radio communication of the communication terminal 15 is started (by starting the radio communication module or turning on the power of the communication terminal 15). In this case, the communication terminal 15 establishes the communication link 25 with the radio base station 31 as described above. The communication link 25 is established after communication for authentication and connection establishment is performed between the establishing unit 161 of the communication terminal 15 and the radio base station 31. Note that step S701 corresponds to the establishment 901 in FIG.

  In step S <b> 702, the receiving unit 162 acquires device connection information from the device server 11 through the communication link 25. As described above, when there are a plurality of device servers in the communication system 50, the device connection information is acquired from each of the plurality of device servers. In order to acquire the device connection information, the communication terminal 15 transmits a device connection information acquisition request to the device server 11 in advance, and the device server 11 transmits to the communication terminal 15 in response to the transmitted acquisition request. You may make it acquire by the receiving part 162 receiving. Alternatively, the device server 11 may periodically transmit the latest device connection information at that time, and the reception unit 162 may receive the transmitted device connection information. Note that step S702 corresponds to the device connection information 902 and 903 in FIG.

  In step S703, the accepting unit 165 accepts designation information indicating a designated device designated by the user. Here, the case where the designated device designated by the user is the device 35 will be described below. Note that step S703 corresponds to “accept device designation” 904 in FIG.

  In step S <b> 704, the radio wave strength determining unit 164 acquires the received radio wave strength of the radio wave received from the wireless base station 32 by the WNIC 155 of the communication terminal 15. Here, the reason why the wireless base station 32 is selected is based on the device connection information acquired from the device server 11, but the device 35 and the wireless base station 32 which are designated devices designated by the user in step S703. Is associated with the device connection information. Note that step S704 corresponds to “obtain received radio wave intensity” 905 in FIG.

  In step S705, the radio wave intensity determination unit 164 determines whether or not the received radio wave intensity acquired in step S704 is equal to or greater than a first threshold value.

  In step S705, when the radio field strength determination unit 164 determines that the received radio field strength is equal to or higher than the first threshold (Yes in step S705), the establishment unit 161 establishes the communication link 25 with the radio base station 31 in step S706. Disconnect. Note that step S705 corresponds to the cutting 906 in FIG.

  In step S <b> 707, the establishing unit 161 establishes the communication link 26 with the radio base station 32. Note that step S707 corresponds to the establishment 907 in FIG.

  In step S <b> 708, the device communication unit 163 performs USB communication with the device 35 via the wireless base station 32 and the device server 11. Note that step S708 corresponds to the USB communication 908 in FIG.

  On the other hand, if the radio field strength determining unit 164 determines in step S705 that the received radio field strength is not equal to or greater than the first threshold (No in step S705), the process proceeds to step S711.

  In step S <b> 711, the device communication unit 163 performs USB communication with the device 35 via the wireless base station 31, the wireless base station 32, and the device server 11. That is, the device communication unit 163 performs USB communication using the established communication link 25 without switching to the radio base station by the establishment unit 161.

  FIG. 8 is a flowchart showing processing of the device server according to the present embodiment.

  In step S801, the generation unit 111 generates device connection information indicating information indicating the device 35 and information indicating the radio base station 32 in association with each other.

  In step S802, the transmission unit 112 transmits the device connection information generated by the generation unit 111 in step S801 to the communication terminal 15. The transmitted device connection information is received by the communication terminal 15 through the communication link 25 established between the radio base station 31 and the communication terminal 15. Note that step S802 corresponds to communication of the device connection information 902 in FIG.

  In step S803, the USB communication between the communication terminal 15 and the device 35 through the communication link 26 established between the wireless base station 32 and the communication terminal 15 is relayed. Of course, whether the communication link 25 or the communication link 26 is routed depends on the determination result of step S705 in FIG. 7, but FIG. 9 shows a case where the communication link 26 is selected. Note that step S803 corresponds to the USB communication 908 in FIG.

  Next, a communication path for communication between the communication terminal and the device server will be described while comparing the case of the conventional technique and the case according to the present embodiment.

  FIG. 10A is an explanatory diagram of a communication path between a device server and a communication terminal in the prior art.

  A communication system 50A shown in FIG. 10A is a communication system configured by using a conventional device server 1001 and a communication terminal 1002 in place of the device server 11 and the communication terminal 15 according to the present embodiment.

  In the communication system 50 </ b> A, when the communication terminal 1002 that initially establishes the communication link 25 with the radio base station 31 tries to perform USB communication with the device 35 via the device server 1001, communication is performed on the communication path 1005. That is, the communication terminal 1002 uses a communication path 1005 that passes through the device server 1001 using the established communication link 25. A communication path 1005 is a communication path between the communication terminal 1002 and the radio base station 32 via the radio base station 31, the communication link 25, and the LAN 40.

  FIG. 10B is an explanatory diagram of a communication path between the communication terminal and the device server according to Embodiment 1.

  A communication system 50 shown in FIG. 10B is a communication system formed using the device server 11 and the communication terminal 15 according to the present embodiment.

  In the communication system 50, when the communication terminal 15 that initially establishes the communication link 25 with the wireless base station 31 tries to perform USB communication with the device 35 via the device server 11, the communication terminal 10 communicates with the communication path 1015. That is, the communication terminal 15 disconnects the established communication link 25 and newly establishes a communication link 26 with the radio base station 32 when the received radio wave intensity of the radio wave from the radio base station 32 is equal to or higher than a certain level. The communication path 1015 passing through the device server 11 using the established communication link 26 is used. The communication path 1015 is a communication path that passes only through the communication link 26 between the communication terminal 15 and the radio base station 32. As described above, according to the communication terminal 15 and the device server 11 according to the present embodiment, the communication terminal 15 and the device server 11 can perform communication through a more appropriate route.

  As described above, according to the communication system according to the present embodiment, a communication terminal is associated with a device to be connected by a device server connected with a predetermined connection standard among a plurality of radio base stations. A communication link can be established with the radio base station, and communication with the device can be performed via the established communication link.

  According to the prior art, when the communication quality of the communication link established before attempting to connect to the device is good, the new communication link is not established as described above. Therefore, the communication path for communication with the device with the communication terminal is not necessarily optimal.

  According to the present invention, even if the communication quality of a communication link established before attempting to connect to a device is good, a new communication is established with a radio base station corresponding to the device to which the communication terminal is to be connected. Establish a communication link to Thus, the communication system according to one embodiment of the present invention can select a more appropriate communication path between the communication terminal and the device server.

  In addition, when the communication terminal can perform good communication with the radio base station corresponding to the device to which the communication terminal is to connect, the communication terminal newly establishes a communication link with the radio base station. Therefore, the communication system can select a more appropriate communication path between the communication terminal and the device server, and can communicate well with the selected communication path.

  In addition, the communication terminal is larger than the received radio wave intensity threshold (second threshold) used for roaming as a criterion for determining whether or not the communication quality with the radio base station corresponding to the device to which the communication terminal is to be connected is good. Use a threshold. In other words, when the received radio wave intensity of a radio wave received from a radio base station that newly establishes a communication link satisfies a stricter standard than that of AP switching by roaming, AP switching by communication path selection according to the present invention is performed. To. Therefore, the communication system can select a more appropriate communication path between the communication terminal and the device server, and can communicate well with the selected communication path.

  Further, the communication terminal establishes a communication link with a radio base station corresponding to the device (designated device) designated by the user. The communication terminal communicates via the established communication link, thereby performing communication that becomes an appropriate communication path with the designated device.

  In addition, when a device ID indicating a device is acquired, the communication terminal can identify a wireless communication path of a wireless base station corresponding to the device, and can establish a new communication link in the identified wireless communication path. . As a result, a new communication link can be established with the radio base station.

  In addition, in a communication system including a plurality of radio base stations having the same SSID, the communication terminal selects and selects a radio base station suitable for communicating with a device from the plurality of radio base stations. It is possible to communicate with a device through a communication path via a wireless base station.

  In addition, when a communication terminal communicates with a USB device using a device server that relays USB communication performed between the communication terminal and the USB device, the communication terminal communicates with a wireless base station corresponding to the device server. A link can be established.

  In addition, the same effect as described above can be achieved in a wireless base station having a device server function or a device server having a wireless base station function.

(Modification 1 of Embodiment 1)
In this modification, a communication system in which a plurality of device servers are connected to a plurality of radio base stations, and a communication system that selects a more appropriate communication path between the communication terminal and the device server will be described.

  FIG. 11 is a network configuration diagram of a communication system 51 according to this modification.

  A communication system 51 illustrated in FIG. 11 includes device servers 11A and 11B, a communication terminal 15, wireless base stations 31 and 32, and LANs 40, 41A, and 41B. Of the above components, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The device server 11A is connected to the printer A and the display device A by a USB cable. Each of the printer A and the display device A corresponds to the device 35 in the first embodiment.

  The device server 11B is connected to the printer B and the display device B by a USB cable. Each of the printer B and the display device B corresponds to the device 35 in the first embodiment.

  FIG. 12A is an explanatory diagram illustrating an example of device connection information created from device connection information acquired from a plurality of radio base stations according to the present modification.

  The device connection information T1201 illustrated in FIG. 12A includes a device ID, an SSID, and a BSSID, similarly to the device connection information T601.

  When there are a plurality of device servers and a plurality of devices as shown in FIG. 11, there are as many entries as the number of devices in the device connection information T1201 shown in FIG. 12A. Since each of the plurality of device servers (11A and 11B) transmits device connection information about the device connected to the own device, the communication terminal 15 receives the device connection information transmitted by the device server, and receives the received device. This is because the integrated connection information is stored as device connection information T1201.

  Specifically, the device connection information T1201 includes printer A (PRT-A), display device A (DISP-A), printer B (PRT-B), and display device B (DISP-B) as device IDs. Have. For each device ID, the SSID and BSSID of the wireless communication path provided by the wireless base station to which the device with the device ID is connected by USB are shown.

  In the following, processing when the communication terminal 15 initially establishes the communication link 25 with the wireless base station 31 and then tries to perform USB communication with the printer B will be described.

  The receiving unit 162 of the communication terminal 15 receives the device connection information T1201 in step S702 (FIG. 7). Then, when communicating with a device associated with the SSID and BSSID of the wireless base station 32 among the devices indicated by the device ID of the device connection information T1201, the establishing unit 161 sets the established communication link 25. Disconnect (step S706 in FIG. 7), and establish a new communication link 26 on the communication path 22 specified by the SSID and BSSID associated with the device ID of the other party with which communication is performed (step S707 in FIG. 7). . Then, it communicates with the device through the newly established communication link 26.

  As described above, according to the communication system according to the present modification, even in a communication system in which a plurality of device servers are connected to a plurality of radio base stations, a more appropriate communication path between the communication terminal and the device server. Can be selected.

(Modification 2 of Embodiment 1)
In this modification, a communication system in which a device server is connected to a LAN to which a plurality of radio base stations are connected, and a communication system that selects a more appropriate communication path between the communication terminal and the device server Will be described.

  FIG. 12B is a network configuration diagram of the communication system according to the second modification.

  A communication system 50B illustrated in FIG. 12B includes a device server 11, a communication terminal 15, wireless base stations 31 and 32, a device 35, LANs 40 and 41C, and a connection cable 42. Of the above components, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The communication system 50B includes a LAN 41C instead of the LAN 41 in the communication system 50 according to the first embodiment. Other points are the same as those of the LAN 41 in the communication system 50 according to the first embodiment.

  The LAN 41C is connected to the device server 11 and the LAN 40. When the device server 11 communicates with the radio base station 32, a communication path via the LANs 41C and 40 is used.

  In communication system 50B, as in communication system 50 in the first embodiment, the communication terminal selects a more appropriate communication path by including the path characteristics between the communication terminal and the apparatus server in the apparatus connection information. can do. For example, when there is a router between the wireless base station 31 and the wireless base station 32 on the LAN 40, the communication terminal 15 can communicate with the device server 11 in a communication path with a smaller number of routers. Can be selected. That is, if the device server 11 includes the number of routers on the communication path in the device connection information, the communication terminal 15 that has received the device connection information can select a communication path with a smaller number of routers. You can choose. The number of routers on the communication path can be acquired by a routing protocol such as RIP (Routing Information Protocol).

  FIG. 12C is an explanatory diagram illustrating an example of device connection information created from device connection information acquired from a plurality of radio base stations according to the present modification.

  FIG. 12C shows device connection information T1211 in which a column indicating the number of routers is newly added to the device connection information T601 shown in FIG. When the communication terminal having the device connection information T1211 communicates with the device PRT1, the wireless base station (in this example, the SSID is SS3 and the BSSID is BS6 so that the number of routers passing through the communication path is the smallest). Select a certain radio base station. This selection may be automatically selected by the communication terminal, or may be selected by the user by indicating a plurality of routes.

  In addition, as a path | route characteristic, you may use the parameter | index reflecting the classification or the zone | band of the communication link of LAN40 instead of the number of routers mentioned above.

  As described above, according to the communication system according to the present modification, when there is a network device such as a router on the LAN connecting the wireless base stations, the communication path through the optimum network device is used. Can communicate.

(Embodiment 2)
In this embodiment, a communication system in which SSIDs of a plurality of radio base stations are different from each other, and a more appropriate communication path is selected between a communication terminal and a device server will be described.

  FIG. 13 is a network configuration diagram of the communication system according to the present embodiment.

  The communication system 52 includes device servers 11A and 11B, a communication terminal 15, wireless base stations 31 and 32B, and LANs 40, 41A and 41B. Of the above components, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The difference from the first embodiment is that the radio base station 32B has an SSID different from that of the radio base station 31 as attribute information.

  Similarly to the radio base station 31, the radio base station 32B is a radio base station device having a radio communication interface. The radio base station 32B establishes a communication link 26B with the communication terminal 15 and performs radio communication. In the attribute information 22C of the communication path 22B of the radio base station 32B, the SSID is “SS2” and the BSSID is “BS2”. That is, the communication path 21 of the radio base station 31 and the communication path 22B of the radio base station 32B have different SSIDs and different BSSIDs. The radio base station 32B corresponds to a second base station.

  FIG. 14 is an explanatory diagram showing an example of device connection information created from device connection information acquired from a plurality of radio base stations according to this modification.

  Device connection information T1401 shown in FIG. 14 includes a device ID, an SSID, and a BSSID, similarly to the device connection information T601.

  As shown in FIG. 14, the device connection information T1401 indicates the SSID and BSSID of the radio base station connected to the device server connected to the device for each device. Since each of the plurality of device servers (11A and 11B) transmits device connection information about the device connected to the own device, the communication terminal 15 receives the device connection information transmitted by the device server, and receives the received device. This is because the connection information integrated is stored as device connection information T1401.

  Initially, when the communication terminal 15 establishes the communication link 25 with the radio base station 31 and then tries to perform USB communication with the printer B, the same processing as in the first modification of the first embodiment is performed. Communication with the device through the newly established communication link 26 is possible.

  As described above, according to the communication system according to the present embodiment, the communication terminal includes a plurality of wireless base stations having different SSIDs. It is possible to select an appropriate radio base station for communication and communicate with a device through a communication path via the selected radio base station.

(Embodiment 3)
In the present embodiment, a communication system in which a wireless base station and a device server communicate with each other by wireless communication, and a communication system that selects a more appropriate communication path between a communication terminal and a device server will be described.

  FIG. 15 is a network configuration diagram of the communication system according to the present embodiment.

  The communication system 53 includes a device server 11 </ b> C, a communication terminal 15, radio base stations 31 and 32, a LAN 40, and a connection cable 42. Of the above components, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The difference from the first embodiment is that the device server 11C can communicate with the radio base station 32 through the communication link 27.

  In FIG. 15, a process when the communication terminal 15 initially establishes the communication link 26 with the radio base station 32 and then tries to perform USB communication with the device 35 will be described below.

  The radio field strength determination unit 164 of the communication terminal 15 acquires the received radio field strength of the radio wave received by the WNIC 155 from the radio base station 31 instead of the process of step S704 in FIG. Here, the reason why the radio base station 31 is selected will be described as follows.

  Since the designated device designated by the user is the device 35, and the wireless base station 32 is the wireless base station 32 connected to the device server 11 connected to the device 35 according to the USB standard via the LAN 40, Embodiment 1 or 2 Therefore, it can be said that it is appropriate for the communication terminal 15 to establish a communication link with the radio base station 32. However, unlike the first or second embodiment, this embodiment differs from the first or second embodiment in that the radio base station 32 has established a communication link with the device server 11C. Degradation or throughput reduction.

  Therefore, in the present embodiment, the communication terminal 15 establishes a communication link with a suitable radio base station 31 that is a radio base station excluding the radio base station 32. As described in the first embodiment, the selection of a suitable radio base station may be instructed by the device server 11C to the communication terminal 15 by the device connection information, or as described in the second modification of the first embodiment. In addition, the communication terminal 15 side may select based on the device connection information. In any case, in a communication system in which a wireless base station and a device server communicate with each other by wireless communication, it is important to select a base station to be connected to a communication terminal from other than “a wireless base station to which a device server is connected”. It is. By doing so, the communication quality or throughput of the communication link between the device server 11C and the radio base station 32 and the communication link between the communication terminal 15 and the radio base station 31 can be maintained.

  For the processing after step S704 in FIG. 7 and the processing shown in FIG. 8, the AP switching processing in the present embodiment is realized by performing processing in which the radio base station 31 and the radio base station 32 are replaced. can do.

  As described above, according to the communication system according to the present embodiment, when a device server is connected to a wireless base station by wireless communication, an appropriate communication path from which the wireless communication is not performed is appropriate. Wireless communication can be performed on the selected communication path.

  While the communication system of the present invention has been described based on the embodiment, the present invention is not limited to this embodiment. Unless it deviates from the meaning of this invention, the form which carried out the various deformation | transformation which those skilled in the art can think to this embodiment, and the structure constructed | assembled combining the component in different embodiment is also contained in the scope of the present invention. .

  The present invention is applicable to a communication system that selects a more appropriate communication path between a communication terminal and a device server. Specifically, it can be used for a wireless LAN or a wired LAN in a factory or an office.

11, 11A, 11B, 11C, 1001 Equipment server 15, 1002 Communication terminal 21, 22, 22B Communication path 21A, 22A, 22C Attribute information 25, 26, 26B, 27 Communication link 31, 32, 32B Wireless base station 35 Equipment 40 41, 41A, 41B, 41C LAN
42 Connection cable 50, 50A, 50B, 51, 52, 53 Communication system 101, 151, 301 CPU
102, 152, 302 ROM
103, 153, 303 RAM
104, 154, 304 Storage device 105, 306 NIC
106 USB-IF
111 Generation Unit 112 Transmission Unit 113 Relay Unit 155, 305 WNIC
161 Establishing unit 162 Receiving unit 163 Device communication unit 164 Radio wave strength determining unit 165 Accepting unit 1005, 1015 Communication path T601, T1201, T1211, T1401 Device connection information

Claims (14)

A communication system including a device server connected to a device according to a predetermined connection standard, and a communication terminal that communicates with the device via the device server,
The communication terminal is a first base station which is an arbitrary radio base station, or a radio base station connected to the device server and connected to the first base station via a network. Can communicate with the device server through wireless communication with a second base station;
The device server is
A generating unit that generates device connection information indicating the information indicating the device and the information indicating the second base station in association with each other;
A transmitter that transmits the device connection information generated by the generator to the communication terminal through a first communication link established between the first base station and the communication terminal;
A relay unit that relays communication between the communication terminal and the device;
The communication terminal is
An establishing unit for establishing the first communication link with the first base station;
A receiver that receives the device connection information transmitted by the transmitter via the first communication link;
A device communication unit that performs communication with the device;
The establishing unit further includes:
When the communication terminal communicates with the device, the established first communication link is disconnected, and the second base station associated with the device in the device connection information received by the receiving unit Establish a second communication link between them,
The device communication unit is
A communication system that performs communication with the device through the second communication link by being relayed by the relay unit. The communication terminal further includes:
A radio field strength judging unit for judging whether or not the received radio wave strength of radio waves received from the second base station is equal to or higher than a first threshold;
The establishment unit
When the radio field intensity determination unit determines that the received radio field intensity is not equal to or greater than the first threshold, disconnecting the first communication link and establishing the second communication link are prohibited,
The relay unit further includes:
The communication system according to claim 1, wherein communication between the communication terminal and the device through the first communication link is relayed. The radio field intensity determination unit
A value larger than a predetermined second threshold value used for roaming of the radio base station by the communication terminal is used as the first threshold value to determine whether the received radio wave intensity is equal to or higher than the first threshold value. The communication system according to claim 2. The communication terminal further includes:
A reception unit that receives designation information indicating a designated device designated by a user;
The establishment unit
When the receiving unit receives the device connection information, the second communication with the radio base station associated in the device information with the designated device indicated by the designation information received by the receiving unit. The communication system according to any one of claims 1 to 3, wherein a link is established. The device connection information includes information indicating a device ID that can identify the device, an SSID (Service Set Identifier) and a BSSID (Basic Service Set Identifier) of a wireless communication path provided by the second base station in association with each other. Including
The establishment part
When the receiving unit receives the device connection information, the second communication link with the second base station based on the SSID and BSSID associated with the device ID included in the received device connection information. The communication system according to any one of claims 1 to 4. The communication system according to claim 5, wherein an ESSID of a wireless communication path provided by the first base station and an ESSID of a wireless communication path provided by the second base station are the same. The communication system according to claim 5, wherein an ESSID of a wireless communication path provided by the first base station and an ESSID of a wireless communication path provided by the second base station are different from each other. The communication system according to any one of claims 1 to 7, wherein the predetermined connection standard is a USB (Universal Serial Bus) standard. The communication system according to claim 1, wherein the device server includes the second base station inside the device server. A communication system including a device server connected to a device according to a predetermined connection standard, and a communication terminal that communicates with the device via the device server,
The communication terminal can communicate with the device server through wireless communication with an arbitrary wireless base station in the communication system,
The device server is
A generator for generating device connection information indicating information indicating the device and information indicating a path characteristic between the radio base station and itself;
A transmission unit that transmits the device connection information generated by the generation unit to the communication terminal;
A relay unit that relays communication between the communication terminal and the device;
The communication terminal is
An establishing unit for establishing a wireless communication link with an arbitrary wireless base station;
A receiver that receives the device connection information transmitted by the transmitter via the wireless communication link;
A device communication unit that performs communication with the device;
The establishing unit further includes:
When the communication terminal communicates with the device, it selects the most suitable radio base station based on the device connection information received by the receiving unit and establishes a new radio communication link with the radio base station,
The device communication unit is
A communication system that performs communication with the device through the newly established wireless communication link by being relayed by the relay unit. A communication system including a device server connected to a device according to a predetermined connection standard, and a communication terminal that communicates with the device via the device server,
The communication terminal is a first base station that is an arbitrary radio base station, or a radio base station that is connected to the device server via a radio communication line and is connected to the first base station via a network. It is possible to communicate with the device server through wireless communication with a second base station that is a base station,
The device server is
A generator that generates device connection information indicating information indicating the device and information indicating a wireless base station in the communication system;
A transmission unit that transmits the device connection information generated by the generation unit to the communication terminal;
A relay unit that relays communication between the communication terminal and the device;
The communication terminal is
An establishing unit for establishing a wireless communication link with an arbitrary wireless base station;
A receiver that receives the device connection information transmitted by the transmitter via the wireless communication link;
A device communication unit that performs communication with the device;
The establishing unit further includes:
When the communication terminal communicates with the device, a new wireless communication link is established with the first base station that is a device excluding the second base station,
The device communication unit is
A communication system that performs communication with the device through the newly established wireless communication link by being relayed by the relay unit. A device server connected to a device with a predetermined connection standard,
The communication terminal that communicates with the device via the device server is a first base station that is an arbitrary wireless base station, or a wireless base station that is connected to the device server and is connected to the first base via a network. Can communicate with the device server through a second base station which is a radio base station connected to the station,
The device server is
A generating unit that generates device connection information indicating the information indicating the device and the information indicating the second base station in association with each other;
A transmitter that transmits the device connection information generated by the generator to the communication terminal through a first communication link established between the first base station and the communication terminal;
A device server comprising: a relay unit that relays communication between the communication terminal and the device. A communication terminal that communicates with the device via a device server connected to the device with a predetermined connection standard,
The communication terminal is a first base station which is an arbitrary radio base station, or a radio base station connected to the device server and connected to the first base station via a network. Can communicate with the device server through wireless communication with a second base station;
The communication terminal is
An establishing unit for establishing the first communication link with the first base station;
A receiver that receives information indicating the device and information indicating the second base station in association with each other via the first communication link;
A device communication unit that performs communication with the device;
The establishing unit further includes:
When the communication terminal communicates with the device, it disconnects the established first communication link and the second base station associated with the device in the device connection information received by the receiving unit. Establish a second communication link with
The device communication unit is
A communication terminal that communicates with the device through the second communication link by being relayed by the relay unit. A communication method in a communication system comprising a device server connected to a device according to a predetermined connection standard, and a communication terminal communicating with the device via the device server,
The communication terminal is a first base station which is an arbitrary radio base station, or a radio base station connected to the device server and connected to the first base station via a network. Can communicate with the device server through wireless communication with a second base station;
The communication method is:
A step of generating device connection information indicating the information indicating the device and the information indicating the second base station in association with each other;
Transmitting the device connection information generated in the generating step to the communication terminal through a first communication link established between the first base station and the communication terminal;
A relay step of relaying communication between the communication terminal and the device;
Establishing the first communication link with the first base station;
Receiving the device connection information transmitted in the transmitting step through the first communication link;
A device communication step for performing communication with the device,
In the establishing step,
When the communication terminal communicates with the device, the established first communication link is disconnected, and the second base station associated with the device in the device connection information received in the receiving step. Establishing the second communication link between them,
In the device communication step,
A communication method for performing communication with the device through the second communication link by being relayed by the relay unit.

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