Communication system, communication method, first relay device, second relay device, and computer program

Abstract

To provide a communication system in which connection can be performed in a WDS mode even in a case where a MAC address of a second relay device that is a connection destination is unknown, a communication method, a first relay device, a second relay device and a computer program.SOLUTION: A first relay device receives input of a predetermined IP address, transmits a scan frame to which the predetermined IP address is set, and searches for a proximate second relay device. The second relay device receives the scan frame and sends back a response frame, to which its own IP frame is set as specific data in a frame, to the first relay device. In a case where the IP address in the received response frame is coincident with the predetermined IP address of which the input is received, the first relay device extracts a MAC address from the received response frame and uses the IP address, of which the input is received, and the extracted MAC address to establish communication with the second relay device in a WDS mode.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a communication system, a communication method, a first relay device, a second relay device, and a computer program that can perform stable wireless communication between wireless communication terminals that are connected to be able to communicate with a relay device in an environment where the positional relationship between adjacent relay devices fluctuates.

Background Art

[0002] When communicating using a wireless LAN, it usually conforms to the IEEE802.11 standard. As one aspect of communication performed using a wireless LAN, communication between a relay device and a wireless communication terminal connected to the relay device is performed in infrastructure mode, and wireless communication may be performed between a plurality of relay devices in a wireless distribution system mode (Wireless Distribution System: hereinafter, WDS mode).

[0003] For example, Patent Document 1 discloses a wireless communication system that performs data communication between wireless LANs. In Patent Document 1, a first relay device that has received a data transmission request from a source wireless communication terminal specifies the MAC address of a second relay device that is a connection destination for communicating in WDS mode, and transmits data to a destination wireless communication terminal connected to the destination relay device (that is, the second relay device).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, in the wireless communication system disclosed in Patent Document 1, the MAC address of the second relay device to which the connection is made is required when connecting in WDS mode. For example, a system administrator who wants to build a wireless communication system in WDS mode faces the problem that they cannot easily identify the MAC address if there are multiple relay devices in close proximity, or if the MAC addresses of multiple relay devices cannot be known because the multiple relay devices are installed on different mobile devices, and as a result they cannot easily build a wireless communication system in WDS mode.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a communication system, a communication method, a first relay device, a second relay device, and a computer program that enable connection in WDS mode even when the MAC address of the second relay device to which the connection is made is unknown. [Means for solving the problem]

[0007] To achieve the above objective, the communication system according to the present invention is a communication system in which a first relay device and a second relay device are capable of wireless communication in WDS mode, wherein the first relay device comprises an input receiving means for receiving input of a predetermined IP address, a frame generation means for generating a scan frame in which the predetermined IP address is set in a wireless frame, and a scan transmission means for transmitting the scan frame for searching for a nearby second relay device, and the second relay device comprises a scan reception determination means for determining whether or not the scan frame has been received, and a response frame generation unit for generating a response frame in which its own IP address is set as unique data in the frame when the scan reception determination means determines that the scan frame has been received, and before the generated The first relay device comprises a response transmission means for sending a response frame back to the first relay device, the first relay device comprising a response receiving means for receiving the response frame, an IP address determination means for determining whether the IP address in the received response frame matches a predetermined IP address received by the input receiving means, a MAC address extraction means for extracting a MAC address from the received response frame if the IP address determination means determines that the IP address in the received response frame matches a predetermined IP address received by the input receiving means, and a communication establishment means for establishing communication with the second relay device in WDS mode using the IP address received and the extracted MAC address.

[0008] Furthermore, in the communication system according to the present invention, it is preferable that the MAC address extraction means extracts identification information associated with the MAC address from the response frame and identifies the MAC address based on the extracted identification information.

[0009] Next, in order to achieve the above objective, the communication system according to the present invention is a communication system in which a first relay device and a second relay device are capable of wireless communication in WDS mode, wherein the second relay device includes beacon transmission means for transmitting beacon frames in which its own IP address is set as unique data in the frame at regular time intervals, and the first relay device includes input reception means for receiving input of a predetermined IP address, beacon reception means for receiving the beacon frame, IP address determination means for determining whether the IP address in the received beacon frame matches the predetermined IP address received by the input reception means, MAC address extraction means for extracting a MAC address from the received beacon frame when the IP address determination means determines that the IP address in the received beacon frame matches the predetermined IP address received, and communication establishment means for establishing communication with the second relay device in WDS mode using the IP address received and the extracted MAC address.

[0010] Furthermore, in the communication system according to the present invention, it is preferable that the MAC address extraction means extracts identification information associated with the MAC address from the beacon frame and identifies the MAC address based on the extracted identification information.

[0011] Next, in order to achieve the above objective, the present invention provides a communication system in which a first relay device and a second relay device are capable of wireless communication in WDS mode, wherein the first relay device includes an input receiving means for receiving input of a predetermined IP address, a frame generating means for generating a scan frame in which the predetermined IP address is set in a wireless frame, and a scan transmitting means for transmitting the scan frame to search for a nearby second relay device, and the second relay device includes a scan reception determination means for determining whether or not the scan frame has been received, and if the scan reception determination means determines that the scan frame has been received, the IP address in the received scan frame matches its own IP address. The system comprises: an IP address determination means for determining whether or not to perform a scan; a response frame generation unit that generates a response frame in which the IP address of

[0012] Furthermore, in the communication system according to the present invention, it is preferable that the MAC address extraction means extracts identification information associated with the MAC address from the response frame and identifies the MAC address based on the extracted identification information.

[0013] Next, in order to achieve the above objective, the present invention provides a communication method that enables a first relay device and a second relay device to communicate wirelessly in WDS mode, comprising the steps of: the first relay device receiving input of a predetermined IP address; generating a scan frame in which the predetermined IP address is set in a wireless frame; and transmitting the scan frame to search for a nearby second relay device; the second relay device determining whether or not it has received the scan frame; if it determines that it has received the scan frame, generating a response frame in which its own IP address is set as unique data within the frame; and sending the generated response frame back to the first relay device; further comprising the steps of: the first relay device receiving the response frame; determining whether or not the IP address in the received response frame matches the predetermined IP address that was received as input; if it determines that the IP address in the received response frame matches the predetermined IP address that was received as input, extracting a MAC address from the received response frame; and establishing communication with the second relay device in WDS mode using the IP address that was received as input and the extracted MAC address.

[0014] Next, in order to achieve the above objective, the communication method according to the present invention is a communication method that enables a first relay device and a second relay device to communicate wirelessly in WDS mode, and includes the steps of: the second relay device transmitting a beacon frame in which its own IP address is set as unique data within the frame at regular time intervals; the first relay device receiving input of a predetermined IP address; receiving the beacon frame; determining whether the IP address in the received beacon frame matches the predetermined IP address that was received as input; if it is determined that the IP address in the received beacon frame matches the predetermined IP address that was received as input, extracting a MAC address from the received beacon frame; and establishing communication with the second relay device in WDS mode using the IP address that was received as input and the extracted MAC address.

[0015] Next, in order to achieve the above objective, the present invention provides a communication method that enables a first relay device and a second relay device to communicate wirelessly in WDS mode, comprising the steps of: the first relay device receiving input of a predetermined IP address; generating a scan frame in which the predetermined IP address is set in a wireless frame; and transmitting the scan frame to search for a nearby second relay device; comprising the steps of: the second relay device determining whether or not it has received the scan frame; if it has determined that it has received the scan frame, determining whether or not the IP address in the received scan frame matches its own IP address; if it has determined that the IP address in the received scan frame matches its own IP address, generating a response frame in which its own IP address is set as unique data in the frame; and sending the generated response frame back to the first relay device; further comprising the steps of: the first relay device receiving the response frame; extracting a MAC address from the received response frame; and establishing communication with the second relay device in WDS mode using the IP address that was received and the extracted MAC address.

[0016] Next, in order to achieve the above objective, the first relay device according to the present invention is a first relay device capable of wirelessly communicating with a second relay device in WDS mode, and is characterized by comprising: an input receiving means for receiving input of a predetermined IP address; a frame generating means for generating a scan frame in which the predetermined IP address is set in a wireless frame; a scan transmitting means for transmitting the scan frame for searching for a nearby second relay device; a response receiving means for receiving a response frame from the second relay device in which the IP address of the second relay device is set as unique data in the frame; an IP address determination means for determining whether the IP address in the received response frame matches the predetermined IP address received by the input receiving means; a MAC address extraction means for extracting a MAC address from the received response frame if the IP address determination means determines that the IP address in the received response frame matches the predetermined IP address received by the input receiving means; and a communication establishment means for establishing communication with the second relay device in WDS mode using the IP address received and the extracted MAC address.

[0017] Furthermore, in the first relay device according to the present invention, it is preferable that the MAC address extraction means extracts identification information associated with the MAC address from the response frame and identifies the MAC address based on the extracted identification information.

[0018] Next, in order to achieve the above objective, the first relay device according to the present invention is a first relay device that can wirelessly communicate with a second relay device in WDS mode, and includes an input receiving means for receiving input of a predetermined IP address. ,beforeThe system is characterized by comprising: a beacon receiving means for receiving beacon frames transmitted at regular time intervals, in which the IP address of the second relay device is set as unique data within the frame; an IP address determination means for determining whether the IP address in the received beacon frame matches the predetermined IP address received by the input receiving means; a MAC address extraction means for extracting the MAC address from the received beacon frame if the IP address determination means determines that the IP address in the received beacon frame matches the predetermined IP address received by the input receiving means; and a communication establishment means for establishing communication with the second relay device in WDS mode using the IP address received and the extracted MAC address.

[0019] Furthermore, in the first relay device according to the present invention, it is preferable that the MAC address extraction means extracts identification information associated with the MAC address from the beacon frame and identifies the MAC address based on the extracted identification information.

[0020] Next, in order to achieve the above objective, the computer program according to the present invention is a computer program that can be executed on a first relay device capable of wirelessly communicating with a second relay device in WDS mode, wherein the first relay device is configured to function as: an input receiving means for receiving input of a predetermined IP address; a frame generating means for generating a scan frame in which the predetermined IP address is set in a wireless frame; a scan transmitting means for transmitting the scan frame for searching for a nearby second relay device; a response receiving means for receiving a response frame from the second relay device in which the IP address of the second relay device is set as unique data in the frame; an IP address determination means for determining whether the IP address in the received response frame matches the predetermined IP address received by the input receiving means; a MAC address extraction means for extracting a MAC address from the received response frame if the IP address determination means determines that the IP address in the received response frame matches the predetermined IP address received by the input receiving means; and a communication establishment means for establishing communication with the second relay device in WDS mode using the input IP address and the extracted MAC address.

[0021] Next, in order to achieve the above objective, the computer program according to the present invention is a computer program that can be executed on a first relay device capable of wireless communication with a second relay device in WDS mode, wherein the first relay device is provided with an input receiving means for receiving a predetermined IP address. ,beforeBeacon receiving means for receiving beacon frames transmitted at regular time intervals, in which the IP address of the second relay device is set as unique data in the frame; IP address determination means for determining whether the IP address in the received beacon frame matches the predetermined IP address received by the input reception means; when the IP address determination means determines that the IP address in the received beacon frame matches the predetermined IP address received by the input reception means, MAC address extraction means for extracting the MAC address from the received beacon frame; and communication establishment means for establishing communication with the second relay device in WDS mode using the received IP address and the extracted MAC address.

Advantages of the Invention

[0022] According to the present invention, based on the IP address, the MAC address of the second relay device as the connection destination can be specified. Therefore, when there are multiple adjacent relay devices, or when the MAC addresses of each of the multiple relay devices cannot be grasped because the multiple relay devices are installed on different mobile bodies, etc., even when the MAC address is uncertain, the MAC address of the second relay device as the connection destination can be easily specified, reducing the work burden of the system administrator and enabling the construction of a wireless communication system in WDS mode.

Brief Description of the Drawings

[0023] [Figure 1] It is a block diagram schematically showing the configuration of a communication system according to Embodiment 1 of the present invention. [Figure 2] It is a block diagram showing an example of a configuration when the CPU (Central Processing Unit) etc. of the first relay device (second relay device) according to Embodiment 1 of the present invention is used as a control unit. [Figure 3] It is a functional block diagram of the first relay device and the second relay device according to Embodiment 1 of the present invention. [Figure 4]This is an illustrative diagram of the data structure of a scan frame generated by a first relay device according to Embodiment 1 of the present invention. [Figure 5] This is an illustrative diagram of the data structure of a response frame generated by a second relay device according to Embodiment 1 of the present invention. [Figure 6] This flowchart shows the processing procedure of the control unit of the first relay device according to Embodiment 1 of the present invention. [Figure 7] This is a functional block diagram of the first relay device and the second relay device according to Embodiment 2 of the present invention. [Figure 8] This is an illustrative diagram showing the data structure of a beacon frame generated by a second relay device according to Embodiment 2 of the present invention. [Figure 9] This flowchart shows the processing procedure of the control unit of the first relay device according to Embodiment 2 of the present invention. [Figure 10] Figure 10 is a functional block diagram of the first and second relay devices according to another embodiment of the present invention. [Modes for carrying out the invention]

[0024] The following will describe in detail, with reference to the drawings, a communication system according to an embodiment of the present invention. The following embodiments are not intended to limit the invention as described in the claims, and it goes without saying that not all combinations of characteristic features described in the embodiments are necessarily essential to the solution.

[0025] Furthermore, the present invention can be implemented in many different embodiments and should not be interpreted as being limited to the descriptions of the embodiments. The same elements are denoted by the same reference numerals throughout the embodiments.

[0026] The following embodiments describe a device in which a computer program is introduced into a computer system. As will be apparent to those skilled in the art, the present invention can be implemented as a computer program that can be executed in part by a computer. Therefore, the present invention can take the form of a hardware embodiment, a software embodiment, or a combination of software and hardware embodiments, which is a communication system that enables connection in WDS mode even when the MAC address of the second relay device to which it is connected is uncertain. The computer program can be recorded on any computer-readable recording medium such as a hard disk, DVD, CD, optical memory device, or magnetic storage medium such as an SD card.

[0027] This embodiment allows the MAC address of the second relay device to be connected to to be identified based on the IP address. Therefore, even when MAC addresses are uncertain, such as when there are multiple relay devices in close proximity, or when the MAC addresses of multiple relay devices cannot be determined because they are installed on different mobile devices, the MAC address of the second relay device to be connected to can be easily identified. This reduces the workload of the system administrator and makes it possible to build a wireless communication system in WDS mode.

[0028] Hereinafter, a communication system according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, elements having the same or similar configuration or function are denoted by the same or similar reference numerals, and detailed descriptions are omitted.

[0029] (Embodiment 1) Figure 1 is a schematic block diagram showing the configuration of a communication system according to Embodiment 1 of the present invention. As shown in Figure 1, the communication system 10 according to Embodiment 1 of the present invention is configured such that a first relay device 1, which is connected by wired or wireless means to communicate with one or more terminal devices 3, and a second relay device 2, which is connected by wired or wireless means to communicate with one or more terminal devices 4, can be connected to each other so that wireless communication can be performed in WDS mode.

[0030] Figure 2 is a block diagram showing an example configuration when the CPU (Central Processing Unit) etc. of the first relay device 1 (second relay device 2) according to Embodiment 1 of the present invention is used as a control unit. In Figure 2, the first relay device 1 (second relay device 2) according to Embodiment 1 of the present invention consists of at least a control unit 11 (21) such as a CPU (Central Processing Unit), memory 12 (22), storage device 13 (23), portable disk drive 16 (26), communication interface 17 (27), and an internal bus 18 (28) for connecting the above-mentioned hardware.

[0031] The control unit 11(12) is connected to the aforementioned hardware components of the first relay device 1 (second relay device 2) via the internal bus 18(28), and controls the operation of the aforementioned hardware components, as well as executing various software functions according to the computer program 5 stored in the storage device 13(23). The memory 12(22) is composed of volatile memory such as SRAM and SDRAM, and a load module is deployed when the computer program 5 is executed, and it stores temporary data and the like that generated when the computer program 5 is executed.

[0032] The storage device 13(23) is composed of an internal fixed storage device (hard disk, flash memory), ROM, etc. The computer program 5 may be pre-stored in the storage device 13(23) of Embodiment 1 of the present invention, or it may be downloaded from a portable recording medium 6 such as a DVD, CD-ROM, flash memory, or SD card that contains program and data information, via a portable disk drive 16(26) and stored in the storage device 13(23). When the computer program 5 is executed, it is expanded from the storage device 13(23) to the memory 12(22) and executed. The computer program 5 may, of course, be a computer program downloaded from an external computer via the communication interface 17(27).

[0033] The storage device 13(23) includes a terminal address storage unit 131(231) that stores the IP addresses and MAC addresses of one or more terminal devices 3(4) connected to each relay device via wired or wireless communication, in association with each other. The IP addresses and MAC addresses of the terminal devices 3(4) to be connected may be stored in advance, or they may be updated and stored in real time with the IP addresses and MAC addresses of the connected terminal devices 3(4).

[0034] The communication interface 17(27) is connected to the internal bus 18(28) and, by connecting to an external network such as the Internet, wired LAN or wireless LAN, or WAN, it is possible to send and receive data with one or more terminal devices 3(4), the second (first) relay device 2(1), and other relay devices. The parameter settings of the first relay device 1 and the second relay device 2, and the data stored in the storage device 13(23), are mainly performed from an external computer that is connected via the communication interface 17(27).

[0035] As described above, there is no fundamental difference in hardware configuration between the first relay device 1 and the second relay device 2. Of course, as shown in Figure 2, the first relay device 1 (second relay device 2) may be equipped with input / output interfaces 14 (24) and video interfaces 15 (25), and parameter settings and data storage may be performed by operating on a touch display 7 having an LCD panel or the like connected to each interface. Note that the input / output interfaces 14 (24) and video interfaces 15 (25) do not necessarily have to be equipped in the first relay device 1 (second relay device 2). For example, parameter settings and data storage may be performed from a communication terminal used by the system administrator, which is connected to the communication interface 17 (27).

[0036] Figure 3 is a functional block diagram of the first relay device 1 and the second relay device 2 according to Embodiment 1 of the present invention. In Figure 3, the sequence for constructing the WDS mode communication system 10 from the first relay device 1 to the second relay device 2 will be explained with reference to Figure 4.

[0037] The input receiving unit 101 of the first relay device 1 receives input from a user or administrator of the IP address (a predetermined IP address) set on the second relay device, which will be the communication partner in WDS mode. The predetermined IP address can be received from a terminal device that is connected to the first relay device 1 and capable of communicating with it. Of course, if the first relay device 1 is equipped with a touch display 7 or the like, it may also receive direct input. The input receiving unit 101 is implemented by the control unit 11, the touch display 7, the video interface 15, and the communication interface 17, etc.

[0038] The frame generation unit 102 of the first relay device 1 generates a scan frame in which a predetermined IP address received as input is set as a wireless frame. Here, Figure 4 is an illustrative diagram of the data structure of a scan frame generated by the first relay device 1 according to Embodiment 1 of the present invention. Figure 4(a) shows an illustrative diagram of the data structure of a scan frame, and Figure 4(b) shows an illustrative diagram of the IEEE802.11 frame format. As shown in Figure 4(a), the first relay device 1 generates a scan frame in which the IP address received as input is set in the private area 41 of the data area 42 shown in Figure 4(b). The frame generation unit 102 is realized by a control unit 11, a storage device 13, a memory 12, etc.

[0039] Returning to Figure 3, the scan transmission unit 103 broadcasts the scan frame generated by the frame generation unit 102 towards the surrounding area of ​​its own device (the first relay device 1) in order to search for the nearby second relay device 2. The destination is not specified because it is a broadcast transmission. The scan transmission unit 103 is implemented by the control unit 11, storage device 13, memory 12, and communication interface 17, etc.

[0040] The destination MAC address of the scan frame is set in the IEEE 802.11 header 43 of the IEEE 802.11 frame format. Specifically, in the frame format shown in Figure 4(b), the Address1 storage area 44 is set to "FF:FF:FF:FF:FF:FF" used during broadcast transmission, and the Address2 storage area 45 is set to the MAC address of the first relay device 1, which is the source.

[0041] Returning to Figure 3, the scan reception determination unit 201 of the second relay device 2 determines whether or not it has received a scan frame from the first relay device 1. If the scan reception determination unit 201 determines that it has received a scan frame, the response frame generation unit 202 generates a response frame in which its own IP address is set as unique data within the frame. The scan reception determination unit 201 and the response frame generation unit 202 are implemented by the control unit 21, storage device 23, memory 22, and communication interface 27, etc.

[0042] Figure 5 is an illustrative diagram of the data structure of a response frame generated by the second relay device 2 according to Embodiment 1 of the present invention. Here, Figure 5(a) shows an illustrative diagram of the data structure of the response frame, and Figure 5(b) shows an illustrative diagram of the IEEE 802.11 frame format. As shown in Figure 5(a), the second relay device 2, having determined that it has received a scan frame, generates a response frame in which its own IP address is set in the private area 51 of the data area 52 shown in Figure 5(b).

[0043] Returning to Figure 3, the response transmission unit 203 sends the response frame generated by the response frame generation unit 202 back to the first relay device 1, which is the source of the scan frame. The response transmission unit 203 is implemented by the control unit 21, storage device 23, memory 22, and communication interface 27, etc.

[0044] The source MAC address of the response frame is set in the IEEE 802.11 header 53 of the IEEE 802.11 frame format. Specifically, in the frame format shown in Figure 5(b), the MAC address of the first relay device 1, which is the source of the scan frame (the destination of the response frame), is set in the Address1 storage area 54, and the MAC address of the second relay device 1, which is the source of the response frame, is set in the Address2 storage area 55.

[0045] Returning to Figure 3, the response receiving unit 104 of the first relay device receives a response frame from the second relay device 2. The IP address determination unit 105 determines whether the IP address in the received response frame matches a predetermined IP address that was received as input by the input receiving unit 101. The response receiving unit 104 is implemented by the control unit 11, storage device 13, memory 12, and communication interface 17, etc.

[0046] If the IP address determination unit 105 determines that the IP address in the received response frame matches a predetermined IP address received by the input reception unit 101, the MAC address extraction unit 106 extracts the MAC address from the received response frame. Specifically, it extracts the MAC address set in the Address2 storage area 55 of the frame format shown in Figure 5(b).

[0047] On the other hand, if the IP address determination unit 105 determines that the IP address in the received response frame does not match a predetermined IP address that was received by the input reception unit 101, it discards the received response frame and notifies the response reception unit 104 to wait for the reception of other response frames.

[0048] In this case, if there are multiple second relay devices, there will be multiple response frames for the scan frame transmitted from the scan transmission unit 103. That is, the response receiving unit 104 may receive multiple response frames.

[0049] Therefore, for example, the IP address determination unit 105 may similarly determine whether the IP address of other received response frames received by the response reception unit 104 matches a predetermined IP address. If no response frame matching the predetermined IP address is found, the unit may instruct the scan transmission unit 103 to resend the scan frame generated by the frame generation unit 102, or it may put the unit into a waiting state for input of a predetermined IP address from a user or administrator by the input reception unit 101. The IP address determination unit 105 and the MAC address extraction unit 106 are implemented by the control unit 11, storage device 13, memory 12, etc.

[0050] In the IEEE 802.11 frame format, instead of the MAC address itself, a unique identification information associated with the MAC address is usually stored. Therefore, since the Address2 storage area 55 contains the identification information associated with the MAC address of the second relay device 2, it is sufficient to extract this identification information and then identify the MAC address based on the extracted identification information.

[0051] The communication establishment unit 107 establishes communication with the second relay device 2 in WDS mode using the IP address received as input and the extracted MAC address. Specifically, communication is established between the communication establishment unit 107 of the first relay device 1 and the communication establishment unit 204 of the second relay device through an authentication process and an association process, which involve mutual verification of the channel used, modulation scheme, and MAC address to establish communication, after which the communication transitions to data communication. Note that the processes after the authentication process are not particularly limited as long as they are well known processes, so a detailed explanation is omitted. The communication establishment units 107 and 204 are implemented by a control unit 11 (21), a storage device 13 (23), a memory 12 (22), a communication interface 17 (27), etc.

[0052] Figure 6 is a flowchart showing the processing procedure of the control unit 11 until the first relay device 1 according to Embodiment 1 of the present invention establishes communication with the second relay device 2. As shown in Figure 6, the control unit 11 of the first relay device 1 accepts input of a predetermined IP address (for example, input from a system administrator, etc.) (step S601).

[0053] The control unit 11 generates a scan frame in which a predetermined IP address received as input is set in the wireless frame (step S602), and transmits the generated scan frame (step S603). The destination is not specified because it is a broadcast transmission.

[0054] The control unit 11 receives a response frame generated by the second relay device 2, in which its own IP address is set as unique data within the frame (step S604). The control unit 11 determines whether the IP address in the received response frame matches the predetermined IP address that was received as input (step S605).

[0055] If the control unit 11 determines that the IP address in the received response frame does not match the predetermined IP address that was received as input (step S605: NO), the control unit 11 returns to step S604 and enters a state of waiting for the reception of other response frames. If the control unit 11 determines that the IP address in the received response frame matches the predetermined IP address that was received as input (step S605: YES), the control unit 11 extracts the MAC address from the received response frame (step S606).

[0056] The control unit 11 establishes communication with the second relay device 2 in WDS mode using the IP address received as input and the extracted MAC address (step S607). After communication is established, if communication with the second relay device 2 ends, the first relay device enters a waiting state for IP address input by the user or administrator, or for scan frames from another relay device (a new first relay device).

[0057] As described above, in this embodiment 1, the MAC address of the second relay device 2, which is the connection destination, can be identified based on the IP address. Therefore, even when the MAC address is uncertain, such as when there are multiple relay devices in close proximity, or when the MAC addresses of multiple relay devices cannot be determined because they are installed on different mobile devices, the MAC address of the second relay device 2, which is the connection destination, can be easily identified. This reduces the workload of the system administrator and makes it possible to build a wireless communication system in WDS mode.

[0058] (Embodiment 2) The configuration of the communication system 10 according to Embodiment 2 of the present invention, and the block diagram showing an example configuration when the CPU (Central Processing Unit), etc., of the first relay device 1 (second relay device 2) of the communication system 10 according to Embodiment 2 of the present invention is used as a control unit, are the same as in Embodiment 1, so detailed explanations are omitted by using the same reference numerals. Embodiment 2 differs from Embodiment 1 in that, instead of the first relay device 1 transmitting scan frames, the second relay device 2 transmits beacon frames at regular time intervals.

[0059] Figure 7 is a functional block diagram of the first relay device 1 and the second relay device 2 according to Embodiment 2 of the present invention. In Figure 7, the sequence for constructing the WDS mode communication system 10 from the first relay device 1 to the second relay device 2 will be explained with reference to Figure 8.

[0060] The input receiving unit 101 of the first relay device 1 receives input of the IP address (a predetermined IP address) set on the second relay device 2, which is the WDS communication partner. The predetermined IP address can be received from a terminal device that is connected to the first relay device 1 and capable of communicating with it. Of course, if the first relay device 1 is equipped with a touch display 7 or the like, it may also receive input directly.

[0061] The beacon transmission unit 205 of the second relay device 2 transmits a beacon frame indicating that it is in a connectable state. Figure 8 is an illustrative diagram showing the data structure of a beacon frame generated by the second relay device 2 according to Embodiment 2 of the present invention. Figure 8(a) shows an illustrative diagram of the data structure of a beacon frame, and Figure 8(b) shows an illustrative diagram of the IEEE 802.11 frame format. As shown in Figure 8(a), the second relay device 2 sets its own IP address in the private area 81 of the beacon frame in the data area 82 shown in Figure 8(b). The beacon transmission unit 205 is realized by a control unit 22, a storage device 23, a memory 22, and a communication interface 27, etc.

[0062] The second relay device 2 then transmits the generated beacon frames at regular time intervals (e.g., 100 msec). The beacon frames are incorporated into the data area 82 of the IEEE 802.11 frame format shown in Figure 8(b), similar to Embodiment 1. The destination is not specified, as it is a broadcast transmission.

[0063] The destination MAC address of the beacon frame is set in the IEEE 802.11 header 83 of the IEEE 802.11 frame format. That is, in the frame format shown in Figure 8(b), the Address1 storage area 44 that stores the destination is set to "FF:FF:FF:FF:FF:FF" for the beacon frame, and the Address2 storage area 85 is set to the MAC address of the second relay device 2, which is the source.

[0064] Returning to Figure 7, the beacon receiving unit 108 of the first relay device receives a beacon frame from the second relay device 2. The IP address determination unit 105 determines whether the IP address in the received beacon frame matches a predetermined IP address that has been received as input by the input receiving unit 101. The beacon receiving unit 108 is implemented by the control unit 11, storage device 13, memory 12, and communication interface 17, etc.

[0065] If the IP address determination unit 105 determines that the IP address in the received beacon frame matches a predetermined IP address received by the input reception unit 101, the MAC address extraction unit 106 extracts the MAC address from the received beacon frame. Specifically, it extracts the MAC address set in the Address2 storage area 85 of the frame format shown in Figure 8(b). On the other hand, if the IP address determination unit 105 determines that the IP address in the received beacon frame does not match a predetermined IP address received by the input reception unit 101, it discards the received beacon frame and notifies the beacon reception unit 108 to wait for the reception of other beacon frames. The IP address determination unit 105 and the MAC address extraction unit 106 are implemented by the control unit 11, storage device 13, memory 12, etc.

[0066] In the IEEE 802.11 frame format, instead of the MAC address itself, a unique identification information associated with the MAC address is usually stored. Therefore, since the Address2 storage area 85 contains the identification information associated with the MAC address of the second relay device 2, it is sufficient to extract the identification information and then identify the MAC address based on the extracted identification information.

[0067] The communication establishment unit 107 establishes communication with the second relay device 2 in WDS mode using the IP address received as input and the extracted MAC address. Specifically, communication is established between the communication establishment unit 107 of the first relay device 1 and the communication establishment unit 204 of the second relay device through an authentication process and an association process, which involve mutual verification of the channel used, modulation scheme, and MAC address to establish communication, after which the communication transitions to data communication. Note that the processes after the authentication process are not particularly limited as long as they are well known processes, so a detailed explanation is omitted. The communication establishment units 107 and 204 are implemented by a control unit 11 (21), a storage device 13 (23), a memory 12 (22), a communication interface 17 (27), etc.

[0068] Figure 9 is a flowchart showing the processing procedure of the control unit 11 until communication is established between the first relay device 1 and the second relay device 2 according to Embodiment 2 of the present invention. As shown in Figure 9, the control unit 11 of the first relay device 1 accepts input of a predetermined IP address (for example, input from a system administrator, etc.) (step S901).

[0069] The control unit 11 receives a beacon frame generated by the second relay device 2, in which its own IP address is set as unique data within the frame (step S902). The control unit 11 determines whether the IP address in the received beacon frame matches a predetermined IP address that was received as input (step S903).

[0070] If the control unit 11 determines that the IP address in the received beacon frame does not match the predetermined IP address that was accepted as input (step S903: NO), the control unit 11 returns to step S902 and enters a state of waiting for the reception of other beacon frames. If the control unit 11 determines that the IP address in the received beacon frame matches the predetermined IP address that was accepted as input (step S903: YES), the control unit 11 extracts the MAC address from the received beacon frame (step S904).

[0071] The control unit 11 establishes communication with the second relay device 2 in WDS mode using the IP address received as input and the extracted MAC address (step S905). After communication is established, if communication with the second relay device 2 ends, the first relay device enters a waiting state for IP address input by the user or administrator, or for scan frames from another relay device (a new first relay device).

[0072] As described above, in this embodiment 2, by using a beacon frame that specifies an IP address, the MAC address of the second relay device 2, which is the connection destination, can be identified. Therefore, even when the MAC address is uncertain, such as when there are multiple relay devices in close proximity, or when the MAC addresses of multiple relay devices cannot be determined because the MAC addresses of multiple relay devices are installed on different mobile devices, the MAC address of the second relay device 2, which is the connection destination, can be easily identified. This reduces the workload of the system administrator and makes it possible to build a wireless communication system in WDS mode.

[0073] It should be noted that the present invention is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the spirit of the present invention. For example, in Embodiment 1, the first relay device 1 that transmitted the scan frame determines whether the IP address included in the response frame returned from one or more second relay devices 2 is the same as the IP address that received the input. However, the second relay device 2 may determine whether the IP address included in the scan frame received by itself is the same as the IP address set on itself, and only if it determines that they are the same, it will return a response frame to the first relay device 1. In this case as well, it can be expected that the same effects as in Embodiment 1 will be achieved.

[0074] Figure 10 is a functional block diagram of a first relay device 1 and a second relay device 2 according to another embodiment of the present invention. In Figure 10, the sequence for constructing the WDS mode communication system 10 from the first relay device 1 to the second relay device 2 will also be explained.

[0075] The input receiving unit 101 of the first relay device 1 receives input from a user or administrator of the IP address (a predetermined IP address) set on the second relay device, which will be the communication partner in WDS mode. The predetermined IP address can be received from a terminal device that is connected to the first relay device 1 and capable of communicating with it. Of course, if the first relay device 1 is equipped with a touch display 7 or the like, it may also receive direct input. The input receiving unit 101 is implemented by the control unit 11, the touch display 7, the video interface 15, and the communication interface 17, etc.

[0076] The frame generation unit 102 of the first relay device 1 generates a scan frame in which a predetermined IP address received as input is set as a wireless frame. The data structure of the generated scan frame is the same as in Embodiment 1, so a detailed explanation is omitted. The frame generation unit 102 is implemented by a control unit 11, a storage device 13, a memory 12, etc.

[0077] The scan transmission unit 103 broadcasts the scan frame generated by the frame generation unit 102 toward the surrounding area of ​​its own device (first relay device 1) in order to search for the nearby second relay device 2. The destination is not specified because it is a broadcast transmission. The scan transmission unit 103 is implemented by the control unit 11, storage device 13, memory 12, and communication interface 17, etc.

[0078] The scan reception determination unit 201 of the second relay device 2 determines whether or not it has received a scan frame from the first relay device 1. If the scan reception determination unit 201 determines that a scan frame has been received, the IP address determination unit 205 determines whether or not the IP address in the received scan frame matches the IP address of its own device (the second relay device 2).

[0079] If the IP address determination unit 205 determines that the IP address in the received scan frame does not match the IP address of its own device (second relay device 2), the IP address determination unit 205 discards the received scan frame. If the IP address in the received scan frame matches the IP address of its own device (second relay device 2), the response frame generation unit 202 generates a response frame in which the IP address stored in the received scan frame is the same as its own IP address, and sets this as unique data within the frame. The data structure of the response frame is the same as in Embodiment 1, so a detailed explanation is omitted. The scan reception determination unit 201, IP address determination unit 205, and response frame generation unit 202 are implemented by the control unit 21, storage device 23, memory 22, and communication interface 27, etc.

[0080] The response transmission unit 203 sends the response frame generated by the response frame generation unit 202 back to the first relay device 1, which is the source of the scan frame. The response transmission unit 203 is implemented by the control unit 21, storage device 23, memory 22, and communication interface 27, etc.

[0081] The response receiving unit 104 of the first relay device receives a response frame from the second relay device 2. The MAC address extraction unit 106 extracts the MAC address from the received response frame. The response receiving unit 104 and the MAC address extraction unit 106 are implemented by the control unit 11, storage device 13, memory 12, and communication interface 17, etc.

[0082] In the IEEE 802.11 frame format, instead of the MAC address itself, a unique identification information associated with the MAC address is usually stored. Therefore, since the Address2 storage area 55 contains the identification information associated with the MAC address of the second relay device 2, it is sufficient to extract this identification information and then identify the MAC address based on the extracted identification information.

[0083] The communication establishment unit 107 establishes communication with the second relay device 2 in WDS mode using the IP address received as input and the extracted MAC address. Specifically, communication is established between the communication establishment unit 107 of the first relay device 1 and the communication establishment unit 204 of the second relay device through an authentication process and an association process, which involve mutual verification of the channel used, modulation scheme, and MAC address to establish communication, after which the communication transitions to data communication. Note that the processes after the authentication process are not particularly limited as long as they are well known processes, so a detailed explanation is omitted. The communication establishment units 107 and 204 are implemented by a control unit 11 (21), a storage device 13 (23), a memory 12 (22), a communication interface 17 (27), etc.

[0084] Furthermore, the IP addresses of the present invention are assumed to be assigned to each relay device in advance. However, they do not need to be associated one-to-one with MAC addresses; for example, each connected vehicle may be assigned a unique IP address. In this case, even if the order in which the vehicles are connected or the connected vehicles are changed, the MAC address of the relay device installed in the adjacent vehicle can be reliably extracted based on the IP address. [Explanation of symbols]

[0085] 1. First relay device 2. Second relay device 11, 21 Control Unit 12, 22 memory 13, 23 Storage device 16, 26 disk drives 17, 27 Communication Interfaces 18, 28 Internal bus

Claims

1. A communication system in which a first relay device and a second relay device can communicate wirelessly in WDS mode, The first relay device is An input receiving means that accepts input of a predetermined IP address, Frame generation means for generating scan frames in which the predetermined IP address is set in the wireless frame, A scan transmission means that transmits the scan frame for searching for a nearby second relay device, and Equipped with, The second relay device, A scan reception determination means for determining whether or not the aforementioned scan frame has been received, When the scan reception determination means determines that the scan frame has been received, a response frame generation unit generates a response frame in which its own IP address is set as unique data within the frame, A response transmission means that sends the generated response frame back to the first relay device. Equipped with, The first relay device is A response receiving means for receiving the response frame, An IP address determination means that determines whether the IP address in the received response frame matches the predetermined IP address that was received as input by the input receiving means, If the IP address determination means determines that the IP address in the received response frame matches the predetermined IP address that was received by the input receiving means, the MAC address extraction means extracts the MAC address from the received response frame. A communication establishment means that establishes communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address. A communication system characterized by comprising the following features.

2. The communication system according to claim 1, characterized in that the MAC address extraction means extracts identification information associated with the MAC address from the response frame and identifies the MAC address based on the extracted identification information.

3. A communication system in which a first relay device and a second relay device can communicate wirelessly in WDS mode, The second relay device, The system includes a beacon transmission means that transmits beacon frames at regular time intervals, in which the system's own IP address is set as unique data within the frame. The first relay device is An input receiving means that accepts input of a predetermined IP address, A beacon receiving means for receiving the aforementioned beacon frame, An IP address determination means that determines whether the IP address in the received beacon frame matches the predetermined IP address that was input by the input receiving means, If the IP address determination means determines that the IP address in the received beacon frame matches the predetermined IP address that was received as input, the MAC address extraction means extracts the MAC address from the received beacon frame. A communication establishment means that establishes communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address. A communication system characterized by comprising the following features.

4. The communication system according to claim 3, characterized in that the MAC address extraction means extracts identification information associated with a MAC address from the beacon frame and identifies the MAC address based on the extracted identification information.

5. A communication system in which a first relay device and a second relay device can communicate wirelessly in WDS mode, The first relay device is An input receiving means that accepts input of a predetermined IP address, Frame generation means for generating scan frames in which the predetermined IP address is set in the wireless frame, A scan transmission means that transmits the scan frame for searching for a nearby second relay device, and Equipped with, The second relay device, A scan reception determination means for determining whether or not the aforementioned scan frame has been received, When the scan reception determination means determines that the scan frame has been received, the IP address determination means determines whether the IP address in the received scan frame matches its own IP address. The IP address determination means determines that the IP address in the received scan frame matches its own IP address, and the response frame generation unit generates a response frame in which its own IP address is set as unique data within the frame. A response transmission means that sends the generated response frame back to the first relay device. Equipped with, The first relay device is A response receiving means for receiving the response frame, MAC address extraction means for extracting the MAC address from the received response frame, A communication establishment means that establishes communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address. A communication system characterized by comprising the following features.

6. The communication system according to claim 5, characterized in that the MAC address extraction means extracts identification information associated with the MAC address from the response frame and identifies the MAC address based on the extracted identification information.

7. A communication method that enables a first relay device and a second relay device to communicate wirelessly in WDS mode, By the first relay device, A step of accepting input of a specified IP address, The steps include generating a scan frame in which the predetermined IP address is set in the wireless frame, The steps include: transmitting the scan frame to search for a nearby second relay device; Includes, By the second relay device, The steps include determining whether or not the aforementioned scan frame has been received, When it is determined that the aforementioned scan frame has been received, the steps include generating a response frame in which the IP address of the IP address is set as unique data within the frame, The steps include sending the generated response frame back to the first relay device and Includes, and further By the first relay device, The step of receiving the response frame, The steps include determining whether the IP address in the received response frame matches the predetermined IP address that received the input, If it is determined that the IP address in the received response frame matches the predetermined IP address that received the input, the steps include extracting the MAC address from the received response frame, The steps include establishing communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address, and A communication method characterized by including

8. A communication method that enables a first relay device and a second relay device to communicate wirelessly in WDS mode, By the second relay device, The process includes the step of sending a beacon frame in which the user's own IP address is set as unique data within the frame at regular time intervals, By the first relay device, A step of accepting input of a specified IP address, The steps include receiving the beacon frame, The steps include determining whether the IP address in the received beacon frame matches the predetermined IP address that was received as input, If it is determined that the IP address in the received beacon frame matches the predetermined IP address that was received as input, the steps include extracting the MAC address from the received beacon frame, The steps include establishing communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address, and A communication method characterized by including

9. A communication method that enables a first relay device and a second relay device to communicate wirelessly in WDS mode, By the first relay device, A step of accepting input of a specified IP address, The steps include generating a scan frame in which the predetermined IP address is set in the wireless frame, The steps include: transmitting the scan frame to search for a nearby second relay device; Includes, By the second relay device, The steps include determining whether or not the aforementioned scan frame has been received, When it is determined that the scan frame has been received, the step is to determine whether the IP address in the received scan frame matches the IP address of the user. If it is determined that the IP address in the received scan frame matches its own IP address, the system generates a response frame in which its own IP address is set as unique data within the frame. The steps include sending the generated response frame back to the first relay device and Includes, and further By the first relay device, The step of receiving the response frame, The steps include extracting the MAC address from the received response frame, The steps include establishing communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address, and A communication method characterized by including

10. A first relay device capable of wireless communication with a second relay device in WDS mode, An input receiving means that accepts input of a predetermined IP address, Frame generation means for generating scan frames in which the predetermined IP address is set in the wireless frame, A scan transmission means that transmits the scan frame for searching for a nearby second relay device, A response receiving means that receives a response frame from the second relay device in which the IP address of the second relay device is set as unique data within the frame, An IP address determination means that determines whether the IP address in the received response frame matches the predetermined IP address that was received as input by the input receiving means, If the IP address determination means determines that the IP address in the received response frame matches the predetermined IP address that was received by the input receiving means, the MAC address extraction means extracts the MAC address from the received response frame. A communication establishment means that establishes communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address. A first relay device characterized by comprising the following:

11. The first relay device according to claim 10, characterized in that the MAC address extraction means extracts identification information associated with the MAC address from the response frame and identifies the MAC address based on the extracted identification information.

12. A first relay device capable of wireless communication with a second relay device in WDS mode, An input receiving means that accepts input of a predetermined IP address, A beacon receiving means that receives beacon frames transmitted at regular time intervals, in which the IP address of the second relay device is set as unique data within the frame, An IP address determination means that determines whether the IP address in the received beacon frame matches the predetermined IP address that was input by the input receiving means, If the IP address determination means determines that the IP address in the received beacon frame matches the predetermined IP address that was input by the input receiving means, the MAC address extraction means extracts the MAC address from the received beacon frame. A communication establishment means that establishes communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address. A first relay device characterized by comprising the following:

13. The first relay device according to claim 12, characterized in that the MAC address extraction means extracts identification information associated with a MAC address from the beacon frame and identifies the MAC address based on the extracted identification information.

14. A computer program that can be executed on a first relay device capable of wireless communication with a second relay device in WDS mode, The first relay device is An input receiving means that accepts input of a predetermined IP address, Frame generation means for generating scan frames in which the predetermined IP address is set in the wireless frame, Scan transmission means for transmitting the scan frame for searching for a nearby second relay device, A response receiving means that receives a response frame from the second relay device in which the IP address of the second relay device is set as unique data within the frame. IP address determination means that determines whether the IP address in the received response frame matches the predetermined IP address that was received as input by the input receiving means. If the IP address determination means determines that the IP address in the received response frame matches the predetermined IP address that was input by the input receiving means, the MAC address extraction means extracts the MAC address from the received response frame, and Communication establishment means for establishing communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address. A computer program characterized by being designed to function as such.

15. A computer program that can be executed on a first relay device capable of wireless communication with a second relay device in WDS mode, The first relay device is An input receiving means that accepts input of a predetermined IP address, A beacon receiving means that receives beacon frames transmitted at regular time intervals, wherein the IP address of the second relay device is set as unique data within the frame. IP address determination means that determines whether the IP address in the received beacon frame matches the predetermined IP address that was received by the input receiving means. If the IP address determination means determines that the IP address in the received beacon frame matches the predetermined IP address that was input by the input receiving means, the MAC address extraction means extracts the MAC address from the received beacon frame, and Communication establishment means for establishing communication with the second relay device in WDS mode using the IP address received as input and the extracted MAC address. A computer program characterized by being designed to function as such.

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