Communication system, radio communication device, communication method, and program

Abstract

To provide a communication system, a radio communication device, a communication method, and a program, capable of increasing a data frame transmission time in radio communication in which a transmission time is limited to a certain ratio.SOLUTION: A radio communication device 1 comprises: a connection processing section 111 that generates an association request frame including apparatus information request flag information and transmits the frame to a base station 2 to establish radio communication with the base station 2; an apparatus information acquisition section 112 that when acquiring an apparatus information notification frame transmitted from the base station 2, extracts IP address information and MAC address information included in the acquired apparatus information notification frame; an address identification section 113 that identifies, out of MAC address information stored in an address storage section 131, MAC address information associated with IP address information included in an ARP request frame; and an address notification section 115 that generates an ARP reply frame including the identified MAC address information and notifies a camera 3 of the ARP reply frame.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a communication system, a wireless communication device, a communication method, and a program. [Background technology]

[0002] A wireless LAN access point has been proposed that includes a terminal management means for managing information about wireless terminals connected to the access point via a wireless LAN (Local Area Network); a terminal determination means for, when receiving an ARP request packet from an ARP (Address Resolution Protocol) issuer, identifying the destination of the ARP request packet and determining, based on information from the terminal management means, whether a wireless terminal corresponding to the destination exists among the wireless terminals connected to the access point (see, for example, Patent Document 1); and a proxy response means for, if a wireless terminal corresponding to the destination exists, creating an ARP response packet for the wireless terminal on behalf of the wireless terminal based on information from the terminal management means and returning the ARP response packet to the ARP issuer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-88918 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, a wireless LAN access point such as that described in Patent Document 1 may be used as a system for communicating with a device connected to a wireless slave device capable of wireless communication via a wired connection. In this case, an ARP request packet issued by the device is transmitted to the wireless LAN access point via the wireless slave device. Therefore, the communication time between the wireless slave device and the wireless LAN access point is occupied by the ARP request packet, which reduces the communication time for data communication from the device to the wireless LAN access point. This situation is not desirable for wireless communication standards such as IEEE802.11ah used in Japan, which limit transmission time to a certain percentage.

[0005] The present invention has been made in consideration of the above reasons, and aims to provide a communication system, a wireless communication device, a communication method, and a program that can increase the transmission time of a data frame in wireless communication in which the transmission time is limited to a certain percentage. [Means for solving the problem]

[0006] In order to achieve the above object, a communication system according to the present invention comprises: A communication system including a wireless communication device capable of communicating with a first device and a base station that wirelessly communicates with the wireless communication device, The wireless communication device a connection processing unit that establishes a wireless connection with the base station by generating a management frame including device information request flag information indicating that the management frame requests the base station to transmit IP address information and MAC address information of a second device that can communicate with the base station, and transmitting the management frame to the base station; a device information acquisition unit that, upon receiving a device information notification frame transmitted from the base station and including the IP address information and the MAC address information of the second device, extracts the IP address information and the MAC address information included in the received device information notification frame; an address storage unit that stores the IP address information and the MAC address information of the second device extracted by the device information acquisition unit in association with each other; an address request acquisition unit that acquires an address request frame transmitted from the first device, the address request frame including the IP address information of the second device and requesting notification of MAC address information of the second device; an address specification unit that specifies, when any of the IP address information stored in the address storage unit matches the IP address information included in the acquired address request frame, the MAC address information that is associated with the IP address information included in the address request frame from the MAC address information stored in the address storage unit; an address notification unit that generates an address response frame including the identified MAC address information and transfers the frame to the first device; The base station When the management frame transmitted from the wireless communication device is acquired, if it is determined that the acquired management frame contains the device information request flag information, the device information notification unit generates a device information notification frame including the IP address information and the MAC address information of the second device and transmits the frame to the wireless communication device.

[0007] A wireless communication device according to another aspect of the present invention comprises: A wireless communication device capable of communicating with a first device and wirelessly communicating with a base station, a connection processing unit that establishes a wireless connection with the base station by generating a management frame including device information request flag information indicating that the management frame requests the base station to transmit IP address information and MAC address information of a second device that can communicate with the base station, and transmitting the management frame to the base station; a device information acquisition unit that, upon receiving a device information notification frame including the IP address information and the MAC address information of the second device transmitted from the base station, extracts the IP address information and the MAC address information included in the received device information notification frame; an address storage unit that stores the IP address information and the MAC address information of the second device extracted by the device information acquisition unit in association with each other; an address request acquisition unit that acquires an address request frame transmitted from the first device, the address request frame including the IP address information of the second device and requesting notification of MAC address information of the second device; an address specification unit that specifies, when any of the IP address information stored in the address storage unit matches the IP address information included in the acquired address request frame, the MAC address information that is associated with the IP address information included in the address request frame from the MAC address information stored in the address storage unit; and an address notification unit that generates an address response frame including the identified MAC address information and transfers the frame to the first device.

[0008] A communication method according to another aspect of the present invention comprises: A communication method for a communication system including a wireless communication device capable of communicating with a first device and a base station that wirelessly communicates with the wireless communication device, a step in which the wireless communication device generates a management frame including device information request flag information indicating that the management frame requests the base station to transmit IP address information and MAC address information of a second device that can communicate with the base station, and transmits the management frame to the base station, thereby establishing a wireless connection with the base station; When the base station acquires the management frame transmitted from the wireless communication device, if it determines that the acquired management frame includes the device information request flag information, it generates a device information notification frame including the IP address information and the MAC address information of the second device and transmits the device information notification frame to the wireless communication device; When the wireless communication device acquires the device information notification frame transmitted from the base station, the wireless communication device extracts the IP address information and the MAC address information included in the acquired device information notification frame; a step of storing the extracted IP address information and MAC address information of the second device by the wireless communication device in association with each other; a step of the wireless communication device acquiring an address request frame transmitted from the first device, the address request frame including the IP address information of the second device and requesting notification of MAC address information of the second device; a step in which, when any of the IP address information stored in an address storage unit matches the IP address information included in the acquired address request frame, the wireless communication device identifies the MAC address information associated with the IP address information included in the address request frame from the MAC address information stored in the address storage unit; The method includes a step in which the wireless communication device generates an address response frame including the identified MAC address information and transfers the frame to the first device.

[0009] From another viewpoint, the program according to the present invention is Computer, a connection processing unit that generates a management frame including device information request flag information indicating that a base station is requested to transmit IP address information and MAC address information of a second device that can communicate with the base station, and transmits the management frame to the base station, thereby establishing a wireless connection with the base station; a device information acquisition unit that, upon receiving a device information notification frame transmitted from the base station and including the IP address information and the MAC address information of the second device, extracts the IP address information and the MAC address information included in the received device information notification frame; an address storage unit that stores the IP address information and the MAC address information of the second device extracted by the device information acquisition unit in association with each other; an address request acquisition unit that acquires an address request frame that includes the IP address information of the second device and requests notification of MAC address information of the second device, transmitted from the first device; an address specification unit that specifies, when any of the IP address information stored in the address storage unit matches the IP address information included in the acquired address request frame, the MAC address information that is associated with the IP address information included in the address request frame from the MAC address information stored in the address storage unit; an address notification unit that generates an address response frame including the identified MAC address information and notifies the first device of the generated address response frame; Function as. [Effects of the Invention]

[0010] According to the present invention, a wireless communication device establishes a wireless connection with a base station by generating a management frame including device information request flag information and transmitting it to the base station. When the base station determines that the management frame transmitted from the wireless communication device includes device information request flag information, the base station generates a device information notification frame including IP address information and MAC address information of a second device and transmits it to the wireless communication device. When the wireless communication device acquires the device information notification frame transmitted from the base station, it extracts the IP address information and MAC address information contained in the acquired device information notification frame. When the wireless communication device acquires an address request frame transmitted from a first device, if any of the IP address information stored in the address storage unit matches the IP address information contained in the acquired address request frame, the wireless communication device identifies, from the MAC address information stored in the address storage unit, the MAC address information associated with the IP address information contained in the address request frame, and generates an address response frame including the identified MAC address information to notify the first device. This reduces the frequency of sending address request frames from the wireless communication device to the base station when an address request frame for acquiring MAC address information of a second device is sent from the first device to the wireless communication device, thereby reducing the usage rate of the wireless band and increasing the transmission time of the data frame. This is particularly effective in wireless communication in which the proportion of time that can be used for frame transmission per preset unit time (e.g., per hour) is limited to a certain proportion (e.g., 10%, or 360 seconds). [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating a configuration of a communication system according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram illustrating a hardware configuration of a communication system according to an embodiment. [Figure 3] FIG. 1 is a diagram illustrating a functional configuration of a communication system according to an embodiment. [Figure 4]FIG. 4 is a sequence diagram showing processing of a communication system according to an embodiment. [Figure 5] FIG. 10 is a diagram illustrating the structure of an association request frame according to an embodiment. [Figure 6] FIG. 4 is a sequence diagram showing processing of a communication system according to an embodiment. [Figure 7] FIG. 4 is a sequence diagram showing processing of a communication system according to an embodiment. [Figure 8] 10 is a flowchart illustrating an example of the flow of wireless communication processing executed by the wireless communication device according to the embodiment. [Figure 9] 10 is a flowchart illustrating an example of the flow of wireless communication processing executed by the wireless communication device according to the embodiment. [Figure 10] 10 is a flowchart illustrating an example of the flow of a base station communication process executed by a base station according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] A communication system according to an embodiment of the present invention will be described below with reference to the drawings. The communication system according to the embodiment includes a wireless communication device capable of communicating with a first device, and a base station that wirelessly communicates with the wireless communication device.

[0013] the second device is configured to receive the IP address information of the second device and transmit the management frame to the base station; the wireless communication device has: a connection processing unit that establishes a wireless connection with the base station by generating a management frame including device information request flag information indicating that the base station is to transmit IP address information and MAC address information of a second device that can communicate with the base station; a device information acquisition unit that, upon receiving a device information notification frame including the IP address information and MAC address information of the second device transmitted from the base station, extracts the IP address information and MAC address information included in the received device information notification frame; an address memory unit that stores the IP address information and MAC address information of the second device extracted by the device information acquisition unit in correspondence with each other; an address request acquisition unit that acquires from a first device an address request frame including the IP address information of the second device and requesting notification of the MAC address information of the first device; an address identification unit that, if any of the IP address information stored in the address memory unit matches the IP address information included in the received address request frame, identifies the MAC address information associated with the IP address information included in the address request frame from the MAC address information stored in the address memory unit; and an address notification unit that generates an address response frame including the identified MAC address information and transmits the address response frame to the first device. When the base station acquires a management frame transmitted from a wireless communication device, if it determines that the acquired management frame contains device information request flag information, the base station has a device information notification unit that generates a device information notification frame including IP address information and MAC address information of the second device and transmits it to the wireless communication device.

[0014] As shown in FIG. 1, the communication system according to this embodiment includes a wireless communication device 1 connected to, for example, a camera 3 via a wired communication path NW2, and a base station 2 connected to a network NW1 including a server 4. The wireless communication device 1 and the base station 2 are wirelessly connected via a wireless communication link NW3. The network NW1 will be described as a wired local area network (LAN), but it may also be a wireless LAN. The wireless communication link NW3 is wireless communication conforming to the IEEE 802.11ah standard. The camera 3 is used, for example, as a surveillance camera for monitoring production equipment. It is a first device having an ARP table storage unit (not shown) that stores ARP (Address Resolution Protocol) table information that associates the MAC (Media Access Control) address of the server 4 with the IP address. The camera 3 transmits an ARP request frame to the wireless communication device 1 via the wired communication path NW2 at each preset ARP table update interval, thereby acquiring an ARP response frame transmitted from the wireless communication device 1. Then, the camera 3 stores the MAC address information contained in the acquired ARP response frame in the ARP table storage unit in association with the IP address information contained in the ARP request frame.

[0015] The server 4 is a second device that acquires image information indicating an image captured by the camera 3, which is transmitted from the camera 3 via the wireless communication device 1 and the base station 2, and stores and manages the acquired image information in an image storage unit (not shown). The server 4 is assigned an IP address assigned by a Dynamic Host Configuration Protocol (DHCP) server (not shown) connected to the network NW1. When an IP address update event occurs in which the IP address assigned to the server 4 is updated, the server 4 generates an IP address update notification frame including IP address information indicating the updated IP address and transmits it to the base station 2. In addition, a device newly connected to the network NW1 generates a network join notification frame including IP address information indicating the IP address assigned to the server 4 and MAC address information indicating the MAC address of the server 4, and transmits it to the base station 2.

[0016] 2, the base station 2 includes a CPU (Central Processing Unit) 201, a main memory 202, an auxiliary memory 203, a wireless module 206, a wired communication interface (hereinafter referred to as "wired communication I / F") 207, and a bus 209 connecting these components together. The main memory 202 is made up of a volatile memory such as a RAM (Random Access Memory), and is used as a working area for the CPU 201. The auxiliary memory 203 is made up of a nonvolatile memory such as a ROM (Read Only Memory), or an SSD (Solid State Drive), HDD (Hard Disk Drive), etc., and stores programs for controlling the base station 2.

[0017] The wireless module 206 communicates using a communication method conforming to a wireless LAN standard, for example, IEEE802.11ah. The wireless module 206 includes an antenna (not shown), a receiving circuit (not shown), a signal processing unit (not shown), and a transmitting circuit (not shown). The receiving circuit receives a wireless signal via the antenna, demodulates the received wireless signal to generate a baseband signal, and outputs the baseband signal to the signal processing unit. The transmitting circuit generates a wireless signal corresponding to a frame to be transmitted by modulating a carrier signal using the baseband signal input from the signal processing unit, and transmits the generated wireless signal via the antenna. The signal processing unit is implemented by, for example, a DSP (Digital Signal Processor), and generates a frame corresponding to the wireless signal received by the receiving circuit based on the baseband signal input from the receiving circuit, and sends the frame to the bus 209.

[0018] The wired communication I / F 207 communicates using a communication method conforming to the Ethernet standard, for example, IEEE802.3. The wired communication I / F 207 has an MDI-X (Medium Dependent Interface Crossover) port, a receiving circuit (not shown), a signal processing unit (not shown), and a transmitting circuit (not shown). The receiving circuit receives a signal via the MDI-X port, demodulates the received signal to generate a baseband signal, and outputs the baseband signal to the signal processing unit. The transmitting circuit generates a signal corresponding to a frame to be transmitted by modulating a carrier signal using the baseband signal input from the signal processing unit, and transmits the generated signal via the MDI-X port. The signal processing unit is realized by, for example, a DSP, and generates a frame corresponding to the signal received by the receiving circuit based on the baseband signal input from the receiving circuit, and sends the frame to the bus 209.

[0019] In the base station 2, the CPU 201 loads a program stored in the auxiliary storage unit 203 into the main storage unit 202 and executes it, thereby functioning as an address acquisition unit 211, a connection processing unit 212, a device information notification unit 213, a frame acquisition unit 214, and a frame transmission unit 215, as shown in FIG. 3. Furthermore, the address acquisition unit 211, the connection processing unit 212, the device information notification unit 213, and the frame transmission unit 215 also function using the wireless module 206 or the wired communication I / F 207 shown in FIG. 2. Furthermore, the auxiliary storage unit 203 shown in FIG. 2 includes an address storage unit 231 that stores IP address information and MAC address information of each device included in the network NW1 including the server 4 in association with each other, as shown in FIG. 3. Furthermore, the main storage unit 202 shown in FIG. 2 includes a frame buffer 221 that temporarily stores data frames transmitted from the wireless communication device 1, as shown in FIG. 3.

[0020] The address acquisition unit 211 is a base station-side address acquisition unit that transmits an address request frame to the server 4 and thereby acquires an address response frame containing MAC address information and IP address information of the server 4. The address acquisition unit 211 then extracts the MAC address information and IP address information contained in the acquired address response frame, associates the extracted MAC address information and IP address information with each other, and stores them in the address storage unit 231. Here, the address request frame is, for example, an ARP request frame, and the address response frame is, for example, an ARP response frame. Furthermore, upon acquiring an ARP request frame transmitted from the wireless communication device 1, the address acquisition unit 211 broadcasts the ARP request frame to each device, including the server 4, connected to the network NW1. Upon acquiring an ARP response frame from each device, the address acquisition unit 211 transmits an ARP response frame containing MAC address information of the sender of the ARP response frame to the wireless communication device 1. Furthermore, when the address acquisition unit 211 acquires an IP address update notification frame transmitted from the server 4, it extracts the MAC address information and IP address information included in the acquired IP address update notification frame, and uses the extracted MAC address information and IP address information to update the MAC address information and IP address information stored in the address storage unit 231. Furthermore, when the address acquisition unit 211 acquires a network join notification frame transmitted from a device that has been newly connected to the network NW1, it extracts the MAC address information and IP address information included in the acquired network join notification frame, and adds the extracted MAC address information and IP address information to the address storage unit 231.

[0021] When the connection processing unit 212 receives a probe request frame transmitted from the wireless communication device 1, the probe request frame includes ESSID (Extended Service Set Identifier) information previously assigned to the wireless network to which the base station 2 belongs. In response to the received probe request frame, the connection processing unit 212 transmits a probe response frame to the wireless communication device 1. Next, when the connection processing unit 212 receives an authentication request frame transmitted from the wireless communication device 1, the connection processing unit 212 transmits an authentication response frame in response to the received probe request frame. Here, the connection processing unit 212 employs, for example, an open system authentication method. Next, when the connection processing unit 212 receives an association request frame from the wireless communication device 1, the connection processing unit 212 transmits an association response frame to the wireless communication device 1 in response to the received association request frame. The connection processing unit 212 also determines whether the received association request frame includes device information request flag information for requesting transmission of IP address information and MAC address information of a device connected via the network NW1 to the base station 2. When the connection processing unit 212 determines that the received association request frame includes device information request flag information, the connection processing unit 212 notifies the device information notification unit 213 of device information request notification information including the determination.

[0022] When the device information request notification information is notified from the connection processing unit 212, the device information notification unit 213 generates a device information notification frame including IP address information and MAC address information of each device connected to the network NW1 including the server 4, which is stored in the address storage unit 231, and transmits the frame to the wireless communication device 1. Note that the device information notification frame may include device identification information (such as a UUID (Universally Unique IDentifier) assigned by software for unique identification) for identifying a device connected to the network NW1, in addition to the IP address information and MAC address information.

[0023] When the frame acquisition unit 214 acquires a data frame including image information indicating an image captured by the camera 3, for example, transmitted from the wireless communication device 1, the frame acquisition unit 214 stores the acquired data frame in the frame buffer 221. The frame transmission unit 215 sequentially transmits the data frames stored in the frame buffer 221 to the server 4 via the network NW1.

[0024] 2, the wireless communication device 1 includes a CPU 101, a main memory unit 102, an auxiliary memory unit 103, a wireless module 106, a wired communication I / F 107, and a bus 109 that interconnects these components. The main memory unit 102 is configured from a volatile memory and is used as a work area for the CPU 101, while the auxiliary memory unit 103 is configured from a non-volatile memory, SSD, HDD, or the like, and stores a program for controlling the wireless communication device 1.

[0025] The wireless module 106 communicates using a communication method conforming to a wireless LAN standard, for example, IEEE802.11ah. The wireless module 106 includes an antenna (not shown), a receiving circuit (not shown), a signal processing unit (not shown), and a transmitting circuit (not shown). The receiving circuit receives a wireless signal via the antenna, demodulates the received wireless signal to generate a baseband signal, and outputs the baseband signal to the signal processing unit. The transmitting circuit generates a wireless signal corresponding to a frame to be transmitted by modulating a carrier signal using the baseband signal input from the signal processing unit, and transmits the generated wireless signal via the antenna. The signal processing unit is implemented, for example, by a DSP, and generates a frame corresponding to the wireless signal received by the receiving circuit based on the baseband signal input from the receiving circuit, and sends the frame to the bus 109.

[0026] The wired communication I / F 107 communicates using a communication method conforming to the Ethernet standard, for example, IEEE802.3. The wired communication I / F 107 has an MDI-X port, a receiving circuit (not shown), a signal processing unit (not shown), and a transmitting circuit (not shown). The receiving circuit receives a signal via the MDI-X port, demodulates the received signal to generate a baseband signal, and outputs the baseband signal to the signal processing unit. The transmitting circuit generates a signal corresponding to a frame to be transmitted by modulating a carrier signal using the baseband signal input from the signal processing unit, and transmits the generated signal via the MDI-X port. The signal processing unit is realized by, for example, a DSP, and generates a frame corresponding to the signal received by the receiving circuit based on the baseband signal input from the receiving circuit, and sends the frame to the bus 109.

[0027] In the wireless communication device 1, the CPU 101 loads a program stored in the auxiliary storage unit 103 into the main storage unit 102 and executes it, thereby functioning as a connection processing unit 111, a device information acquisition unit 112, an address identification unit 113, an address request acquisition unit 114, an address notification unit 115, an address acquisition unit 116, a frame acquisition unit 117, and a frame transmission unit 118, as shown in FIG. 3. Furthermore, the connection processing unit 111, the device information acquisition unit 112, and the frame transmission unit 118 also function using the wireless module 106, etc., shown in FIG. 2. Furthermore, the address request acquisition unit 114, the address notification unit 115, and the frame acquisition unit 117 also function using the wired communication I / F 107, etc., shown in FIG. 2. Furthermore, the main storage unit 102 shown in FIG. 2 has a frame buffer 121 that temporarily stores data frames transmitted from the camera 3, as shown in FIG. 3. 2 includes an address storage unit 131 that stores the IP address information and MAC address information of each device included in the network NW1, including the server 4, in association with each other, and a policy information storage unit 132. The policy information storage unit 132 stores policy information indicating a policy for processing an ARP request frame transmitted from the camera 3 when the IP address information included in the ARP request frame does not exist among the IP address information stored in the address storage unit 131. Specifically, the policy information storage unit 132 stores one of the following two types of policy information that are set in advance by the user. One is discard policy information indicating that the ARP request frame is to be discarded when the IP address information included in the ARP request frame transmitted from the camera 3 does not exist among the IP address information stored in the address storage unit 131. The other is forwarding policy information indicating that if the IP address information contained in the ARP request frame sent from camera 3 does not exist among the IP address information stored in address memory unit 131, the ARP request frame is sent to base station 2 to inquire of base station 2 about the MAC address information corresponding to the IP address information contained in the ARP request frame.

[0028] For example, when the wireless communication device 1 is started up, the connection processing unit 111 transmits to the base station 2 a probe request frame including ESSID information that has been assigned in advance to the wireless network to which the base station 2 belongs. Next, when the connection processing unit 111 acquires a probe response frame transmitted from the base station 2, it transmits an authentication request frame to the base station 2 in response to the probe response frame. Subsequently, when the connection processing unit 111 acquires an authentication response frame transmitted from the base station 2, it generates an association request frame for the base station 2 in response to the authentication response frame, including the above-mentioned device information request flag information, and transmits the association request frame to the base station 2. Thereafter, when the connection processing unit 111 acquires an association response frame transmitted from the base station 2, it notifies the frame transmitting unit 118 of frame transmission permission notification information that permits the frame transmitting unit 118 to transmit a data frame.

[0029] When the device information acquisition unit 112 acquires a device information notification frame transmitted from the base station 2, it extracts the IP address information and MAC address information of each device included in the network NW1, including the server 4, contained in the acquired device information notification frame.

[0030] The address storage unit 131 stores the IP address information and MAC address information of each device included in the network NW1, including the server 4, extracted by the device information acquisition unit 112, in association with each other.

[0031] The address request acquisition unit 114 acquires an ARP request frame transmitted from the camera 3, which includes the IP address information of one of the devices included in the network NW1 including the server 4, and requests notification of the MAC address information of the server 4.

[0032] When the address request acquisition unit 114 acquires an ARP request frame, the address determination unit 113 determines whether any of the IP address information stored in the address storage unit 131 matches the IP address information included in the acquired ARP request frame. If the address determination unit 113 determines that any of the IP address information stored in the address storage unit 131 matches the IP address information included in the acquired ARP request frame, the address determination unit 113 identifies MAC address information associated with the IP address information included in the ARP request frame from the MAC address information stored in the address storage unit 131. The address determination unit 113 then notifies the address notification unit 115 of the identified MAC address information. On the other hand, if the address determination unit 113 determines that there is no IP address information stored in the address storage unit 131 that matches the IP address information included in the acquired ARP request frame, the address determination unit 113 notifies the address notification unit 115 and the address acquisition unit 116 of IP address non-existence notification information.

[0033] The address notification unit 115 transfers to the camera 3 an ARP response frame including the MAC address information identified by the address identification unit 113 or an ARP response frame notified by the address acquisition unit 116. Furthermore, when the address notification unit 115 is notified of IP address non-existence notification information from the address identification unit 113, the address notification unit 115 determines whether or not the policy information storage unit 132 stores the above-mentioned discard policy information. If the address notification unit 115 determines that the policy information storage unit 132 stores discard policy information, it executes processing to discard the acquired ARP request frame.

[0034] The address acquisition unit 116 is a wireless communication device-side address acquisition unit that transmits an ARP request frame to the base station 2 and, upon receiving an ARP response frame transmitted from the base station 2, notifies the address notification unit 115. Specifically, it is assumed that the address acquisition unit 116 is notified of IP address non-existence notification information from the address identification unit 113 and determines that the policy information storage unit 132 stores the above-mentioned forwarding policy information. In this case, the address acquisition unit 116 transmits an ARP request frame to the base station 2 to inquire of the base station 2 about MAC address information corresponding to the IP address information contained in the ARP request frame. Then, upon receiving an ARP response frame transmitted from the base station 2, the address acquisition unit 116 notifies the address notification unit 115 of the received ARP response frame. Furthermore, the address acquisition unit 116 stores the MAC address information contained in the received ARP response frame in the address storage unit 131 in association with the IP address information contained in the ARP request frame.

[0035] After receiving the above-mentioned frame transmission permission notification information from connection processing unit 111, frame acquisition unit 117 acquires a data frame including image information indicating an image captured by camera 3 and transmitted from camera 3, and stores the acquired data frame in frame buffer 121. Frame transmission unit 118 sequentially transmits the data frames stored in frame buffer 121 to base station 2 via wireless communication link NW3.

[0036] Next, processing of the communication system according to this embodiment will be described with reference to FIGS. 4 to 7. Here, it is assumed that the base station 2 acquires, from the server 4, IP address information indicating an IP address previously assigned by the server 4 and MAC address information, and stores these information in the address storage unit 231 in association with each other. First, as shown in FIG. 4, when the wireless communication device 1 starts up, the wireless communication device 1 transmits a probe request frame including ESSID information identifying the wireless network to which the base station 2 belongs to the base station 2 (step S1). On the other hand, when the base station 2 acquires the probe request frame, the base station 2 transmits a probe response frame to the wireless communication device 1 in response (step S2). On the other hand, when the wireless communication device 1 acquires the probe response frame, the wireless communication device 1 transmits an authentication request frame to the base station 2 in response (step S3). On the other hand, when the base station 2 acquires the authentication request frame, the base station 2 transmits an authentication response frame to the wireless communication device 1 in response (step S4). On the other hand, when the wireless communication device 1 receives the authentication response frame, it generates an association request frame including device information request flag information in response to the authentication response frame (step S5), and transmits the generated association request frame from the wireless communication device 1 to the base station 2 (step S6). Here, the association request frame has a 7-octet VIE (Vendor Specific Information Element) field, which is permitted for use by the supplier of the wireless communication device 1 and in which one octet of information indicating the device information request flag information is embedded, as shown in Fig. 5, for example. Returning to Fig. 4, on the other hand, when the base station 2 receives the association request frame, it transmits an association response frame from the base station 2 to the wireless communication device 1 in response to the association request frame (step S7).

[0037] Here, it is assumed that the base station 2 determines that the acquired association request frame includes device information request flag information (step S8). In this case, the device information notifying unit 213 of the base station 2 generates a device information notification frame including IP address information and MAC address information of each device included in the network NW1, including the server 4, stored in the address storage unit 231 (step S9). Subsequently, the generated device information notification frame is transmitted from the base station 2 to the wireless communication device 1 (step S10). Meanwhile, upon acquiring the device information notification frame, the wireless communication device 1 extracts the IP address information and MAC address information included in the acquired device information notification frame. Then, the address storage unit 131 stores the extracted IP address information and MAC address information in association with each other (step S11).

[0038] In this way, a wireless connection is established between the wireless communication device 1 and the base station 2. Then, after the frame transmission permission notification information is notified from the connection processing unit 111, a data frame including image information showing an image captured by the camera 3 is transferred from the camera 3 to the wireless communication device 1 as needed. Then, when the wireless communication device 1 acquires the data frame, the data frame is transmitted from the wireless communication device 1 to the base station 2 via the wireless communication link NW3, and then transmitted to the server 4 via the network NW1 (not shown).

[0039] Thereafter, when the ARP table update time arrives for updating the ARP table information stored in the ARP table storage unit of the camera 3, an ARP request frame is transmitted from the camera 3 to the wireless communication device 1 (step S12). Meanwhile, as shown in FIG. 6, after the wireless communication device 1 acquires the ARP request frame from the camera 3, it determines that any of the IP address information stored in the address storage unit 131 matches the IP address information included in the acquired ARP request frame (step S13). In this case, the wireless communication device 1 identifies the MAC address information associated with the IP address information included in the ARP request frame from the MAC address information stored in the address storage unit 131, and generates an ARP response frame including the identified MAC address information (step S14). Next, the generated ARP response frame is transferred from the wireless communication device 1 to the camera 3 (step S15). Meanwhile, upon acquiring the ARP response frame, the camera 3 updates the ARP table information stored in the ARP table storage unit using the MAC address information included in the acquired ARP response frame (step S16).

[0040] 6, it is assumed that the time for updating the ARP table of the camera 3 has arrived, and after the process of step S12 has been executed, the wireless communication device 1 determines that the IP address information stored in the address storage unit 131 does not match the IP address information included in the acquired ARP request frame (step S17). Then, it is assumed that the wireless communication device 1 determines that the policy information storage unit 132 stores the above-mentioned discard policy information (step S18). In this case, the wireless communication device 1 executes a process of discarding the acquired ARP request frame (step S19).

[0041] On the other hand, as a third example, as shown in FIG. 6, it is assumed that the time to update the ARP table of the camera 3 has arrived, and after the processes of steps S12 and S17 have been executed, the wireless communication device 1 determines that the policy information storage unit 132 stores the above-mentioned forwarding policy information (step S20). In this case, as shown in FIG. 7, an ARP request frame is transmitted from the wireless communication device 1 to the base station 2 (step S21). On the other hand, upon receiving the ARP request frame transmitted from the wireless communication device 1, the base station 2 broadcasts the ARP request frame to devices included in the network NW1, including the server 4 (step S22). On the other hand, upon receiving the ARP request frame including its own IP address information, the server 4 generates an ARP response frame including its own MAC address information in response to the ARP request frame (step S23). Subsequently, the generated ARP response frame is transmitted from the server 4 to the base station 2 (step S24). On the other hand, upon receiving the ARP response frame, the base station 2 transmits an ARP response frame including the MAC address information of the server 4 to the wireless communication device 1 in response to the ARP request frame (step S25). On the other hand, when the wireless communication device 1 acquires the ARP response frame, the ARP response frame including the MAC address information of the server 4 is transferred from the wireless communication device 1 to the camera 3 in response thereto (step S26). On the other hand, when the camera 3 acquires the ARP response frame, it updates the ARP table information stored in the ARP table storage unit using the MAC address information included in the acquired ARP response frame (step S27).

[0042] 7, when an IP address update event occurs in which the IP address assigned to the server 4 is updated, the server 4 generates an IP address update notification frame including IP address information indicating the updated IP address (step S28), and the generated IP address update notification frame is transmitted from the server 4 to the base station 2 (step S29). Meanwhile, when the base station 2 acquires the IP address update notification frame, it extracts the MAC address information and IP address information included in the acquired IP address update notification frame, and updates the MAC address information and IP address information stored in the address storage unit 231 using the extracted MAC address information and IP address information (step S30). Thereafter, the base station 2 generates a device information notification frame including the updated IP address information and MAC address information stored in the address storage unit 231 (step S31), and the generated device information notification frame is transmitted from the base station 2 to the wireless communication device 1 (step S32). On the other hand, when the wireless communication device 1 acquires the device information notification frame, it extracts the IP address information and MAC address information included in the acquired device information notification frame, and updates the IP address information and MAC address information stored in the address storage unit 131 using the extracted IP address information and MAC address information (step S33). Note that when a new device is connected to the network NW1 and a network join notification frame is transmitted from that device to the base station 2, the same processes as those in steps S30 to S33 described above are also executed.

[0043] Next, wireless communication processing executed by the wireless communication device 1 according to this embodiment will be described with reference to FIGS. 8 and 9. This wireless communication processing is initiated when the wireless communication device 1 is started. First, when the wireless communication device 1 is started, the connection processing unit 111 transmits a probe request frame including ESSID information previously assigned to the wireless network to which the base station 2 belongs to the wireless communication device 1 (step S101). Next, when the connection processing unit 111 receives a probe response frame transmitted from the base station 2 (step S102), it transmits an authentication request frame to the base station 2 in response to this (step S103). Subsequently, when the connection processing unit 111 receives an authentication response frame transmitted from the base station 2 (step S104), it generates an association request frame including device information request flag information in response to this and transmits the association request frame to the base station 2 (step S105). Thereafter, the connection processing unit 111 acquires the association response frame transmitted from the base station 2 (step S106), and notifies the frame transmitting unit 118 of frame transmission permission notification information.

[0044] Next, when the device information acquisition unit 112 acquires a device information notification frame transmitted from the base station 2 (step S107), it extracts the IP address information and the MAC address information included in the acquired device information notification frame. Then, the address storage unit 131 stores the IP address information and the MAC address information extracted by the device information acquisition unit 112 in association with each other (step S108).

[0045] Next, the address request acquisition unit 114 determines whether or not an ARP request frame transmitted from camera 3 has been acquired (step S109). If the address request acquisition unit 114 determines that an ARP request frame transmitted from camera 3 has not been acquired (step S109: No), the process of step S117, which will be described later, is executed. On the other hand, it is assumed that the address request acquisition unit 114 determines that an ARP request frame transmitted from camera 3 has been acquired (step S109: Yes). In this case, when the address request acquisition unit 114 acquires an ARP request frame, the address specification unit 113 determines whether any of the IP address information stored in the address storage unit 131 matches the IP address information included in the acquired ARP request frame (step S110). If the address identification unit 113 determines that any of the IP address information stored in the address storage unit 131 matches the IP address information included in the acquired ARP request frame (step S110: Yes), it identifies the MAC address information associated with the IP address information included in the ARP request frame from the MAC address information stored in the address storage unit 131, and notifies the address notification unit 115 of the identified MAC address information. Then, the address notification unit 115 generates an ARP response frame including the MAC address information identified by the address identification unit 113, and transfers the frame to the camera 3 (step S111).

[0046] On the other hand, if the address specification unit 113 determines that the IP address information stored in the address storage unit 131 does not contain IP address information that matches the IP address information contained in the acquired ARP request frame (step S110: No), it notifies the address notification unit 115 and the address acquisition unit 116 of IP address non-existence notification information. Then, the address notification unit 115 determines whether the policy information storage unit 132 stores the above-mentioned discard policy information (step S112). Here, if the address notification unit 115 determines that the policy information storage unit 132 stores discard policy information (step S112: Yes), it executes a process of discarding the acquired ARP request frame (step S113).

[0047] On the other hand, it is assumed that the address acquisition unit 116 has received IP address non-existence notification information from the address identification unit 113 and has determined that the policy information storage unit 132 stores the above-mentioned forwarding policy information, not a discarding policy (step S112: No). In this case, the address acquisition unit 116 transmits an ARP request frame to the base station 2 (step S114), acquires an ARP response frame transmitted from the base station 2 (step S115), and notifies the address notification unit 115 of the acquired ARP response frame. At this time, the address acquisition unit 116 stores the MAC address information included in the acquired ARP response frame in the address storage unit 131 in association with the IP address information included in the ARP request frame. Then, the address notification unit 115 transfers the notified ARP response frame to the camera 3 (step S116).

[0048] Thereafter, the device information acquisition unit 112 determines whether or not a device information notification frame transmitted from the base station 2 has been acquired (step S117). This device information notification frame is transmitted by the base station when the IP address assigned to the server 4 is updated or when a new device is connected to the network NW1. If the device information acquisition unit 112 determines that a device information notification frame has not been acquired (step S117: No), the device information acquisition unit 112 executes the processing of step S119, which will be described later. On the other hand, if the device information acquisition unit 112 determines that a device information notification frame has been acquired (step S117: Yes), the device information acquisition unit 112 extracts the IP address information and MAC address information included in the acquired device information notification frame. Then, the address storage unit 131 stores the IP address information and MAC address information extracted by the device information acquisition unit 112 in association with each other (step S118).

[0049] Next, after receiving the frame transmission permission notification information, frame acquisition unit 117 determines whether or not it has acquired a data frame including image information indicating an image captured by camera 3 and transmitted from camera 3 (step S119). If frame acquisition unit 117 determines that it has not acquired a data frame (step S119: No), it executes the process of step S109 again. On the other hand, if frame acquisition unit 117 determines that it has acquired a data frame (step S119: Yes), it stores the acquired data frame in frame buffer 121. Then, frame transmission unit 1185 sequentially transmits the data frames stored in frame buffer 221 to base station 2 (step S120). Subsequently, it executes the process of step S109 again.

[0050] Next, a base station communication process executed by base station 2 according to this embodiment will be described with reference to Fig. 10. In parallel with this base station communication process, base station 2 executes a process in which, when frame acquisition unit 214 acquires a data frame transmitted from wireless communication device 1, it stores the acquired data frame in frame buffer 221, and frame transmission unit 215 sequentially transmits the data frames stored in frame buffer 221 to server 4 via network NW1. Also, address acquisition unit 211 acquires address response information transmitted from server 4 by transmitting the above-mentioned address request information to server 4 in advance, extracts MAC address information and IP address information included in the acquired address response information, and stores the extracted MAC address information and IP address information in address storage unit 231 in association with each other.

[0051] First, the connection processing unit 212 determines whether or not it has received a probe request frame transmitted from the wireless communication device 1 (step S201). If the connection processing unit 212 determines that it has not received a probe request frame (step S201: No), it executes the processing of step S209, which will be described later. On the other hand, if the connection processing unit 212 determines that it has received a probe request frame (step S201: Yes), it transmits a probe response frame to the wireless communication device 1 in response (step S202). Next, if the connection processing unit 212 receives an authentication request frame transmitted from the wireless communication device 1 (step S203), it transmits an authentication response frame in response (step S204). Next, if the connection processing unit 212 receives an association request frame from the wireless communication device 1 (step S205), it transmits an association response frame to the wireless communication device 1 in response (step S206). Thereafter, the connection processing unit 212 determines whether the acquired association request frame includes device information request flag information for requesting transmission of device information (step S207). If the connection processing unit 212 determines that the acquired association request frame does not include device information request flag information (step S207: No), the process proceeds to step S209, which will be described later.

[0052] On the other hand, if it is determined that device information request flag information is included (step S207: Yes), the connection processing unit 212 notifies the device information request notification information to the device information notification unit 213. Then, the device information notification unit 213 generates a device information notification frame including the IP address information and MAC address information of each device included in the network NW1 including the server 4, which is stored in the address storage unit 231, and transmits the frame to the wireless communication device 1 (step S208).

[0053] Next, the address acquisition unit 211 determines whether or not an ARP request frame transmitted from the wireless communication device 1 has been acquired (step S209). If the address acquisition unit 211 determines that an ARP request frame has not been acquired (step S209: No), the process of step S212, which will be described later, is executed. On the other hand, if the address acquisition unit 211 determines that an ARP request frame has been acquired (step S209: Yes), the address acquisition unit 211 broadcasts the ARP request frame to devices included in the network NW1, including the server 4 (step S210). Then, the address acquisition unit 211 acquires the ARP response frame, and transmits the ARP response frame, including the MAC address information included in the acquired ARP response frame, to the wireless communication device 1 (step S211).

[0054] Next, the address acquisition unit 211 determines whether or not an IP address update notification frame or a network join notification frame has been acquired (step S212). If the address acquisition unit 211 determines that an IP address update notification frame or a network join notification frame has not been acquired (step S212: No), the process of step S201 is executed again. On the other hand, if the address acquisition unit 211 determines that an IP address update notification frame or a network join notification frame has been acquired (step S212: Yes), the address acquisition unit 211 extracts the MAC address information and IP address information included in the acquired IP address update notification frame or network join notification frame, and updates the MAC address information and IP address information stored in the address storage unit 231 using the extracted MAC address information and IP address information (step S213). Thereafter, the device information notification unit 213 generates a device information notification frame including the updated IP address information and MAC address information stored in the address storage unit 231, and transmits the generated frame to the wireless communication device 1 (step S214). Next, the process of step S201 is executed again.

[0055] As described above, in the communication system according to the present embodiment, in the process of establishing a wireless connection with the base station 2, the wireless communication device 1 generates an association request frame including device information request flag information and transmits it to the base station 2. As a result, the base station 2 generates a device information notification frame including IP address information and MAC address information of the server 4 and transmits it to the wireless communication device 1. When the wireless communication device 1 acquires the device information notification frame transmitted from the base station 2, it extracts the IP address information and MAC address information included in the acquired device information notification frame and stores the extracted IP address information and MAC address information in the address storage unit 131 in association with each other. Thereafter, when the wireless communication device 1 acquires an ARP request frame transmitted from a device connected to the wireless communication device 1 by wire (the camera 3 in this example), if any of the IP address information stored in the address storage unit 131 matches the IP address information included in the acquired address request information, the wireless communication device 1 identifies the MAC address information associated with the IP address information included in the address request information from the MAC address information stored in the address storage unit 131, and generates an ARP response frame including the identified MAC address information and transfers it to the camera 3. As a result, when an ARP request frame for obtaining MAC address information of server 4 is sent from camera 3 to wireless communication device 1, wireless communication device 1 can return an ARP response frame itself without forwarding the ARP request frame to base station 2, thereby reducing the frequency of sending ARP request frames from wireless communication device 1 to base station 2 and thereby increasing the transmission time of data frames.

[0056] In Japan, when wireless communication is performed in the sub-gigahertz band using standards such as IEEE 802.11ah, the time used for frame transmission is limited to a duty of 10%. Therefore, it is preferable for wireless communication devices 1 and base stations 2, whose main role is to transmit data frames, to minimize unnecessary frame transmission. Furthermore, in LPWA (Low Power Wide Area) wireless communication technologies such as IEEE 802.11ah, a configuration is generally adopted in which wireless communication devices 1 installed at multiple locations over a relatively wide area transmit data acquired by devices such as sensors and cameras connected to each wireless communication device 1 to a base station 2. In other words, when wireless communication is performed between the wireless communication device 1 and the base station 2 using a wireless communication standard (e.g., IEEE 802.11ah) in which the proportion of time available for frame transmission per preset unit time (e.g., per hour) is limited to a certain proportion (e.g., 10%, or 360 seconds), it is even more important for the wireless communication device 1 to minimize the transmission of wireless frames other than data frames, thereby maximizing the transmission time that can be allocated to transmitting data frames.

[0057] On the other hand, when a device such as a camera 3 connected to the wireless communication device 1 transmits data to a base station 2 connected to the base station 2 via a network NW1 using IP communication, a mechanism for performing so-called ARP resolution by transmitting and receiving an ARP request frame and an ARP response frame is generally used. However, because the wireless communication device 1 transmits wireless frames other than data frames for ARP resolution, this consumes the transmission time that would otherwise be used for transmitting data frames. Therefore, in order to perform ARP resolution without transmitting and receiving ARP request frames and ARP response frames between the wireless communication device 1 and the base station 2, there is a need for a mechanism for the wireless communication device 1 to transmit an ARP response frame on behalf of the device in response to an ARP request frame transmitted from the device.

[0058] In contrast, in this embodiment, when the wireless communication device 1 transmits an association request frame to the base station 2, device information request flag information is embedded in the association request frame to request transmission of IP address information and MAC address information for each device, including the server 4, that communicates with the base station 2 via the network NW1. As a result, when the wireless communication device 1 completes the wireless connection between the base station 2 and the wireless communication device 2, the request from the wireless communication device 1 to the base station 2 to transmit IP address information and MAC address information for each device connected to the base station 2 via the network NW1 can be completed, thereby suppressing subsequent transmission of ARP request frames from the wireless communication device 1 to the base station 2. Furthermore, while the size of the data field of the ARP request frame is 28 octets, the size of the VIE field of the association request frame is 7 octets, as described above, which is ¼ the size of the data field. Therefore, the transmission time can be significantly reduced compared to when the wireless communication device 1 transmits an ARP request frame to obtain MAC address information for each device connected to the base station 2 via the network NW1.

[0059] Furthermore, when the IP address information of the server 4 is updated or when a new device is connected to the network NW1, the address acquisition unit 211 of the base station 2 according to this embodiment acquires the IP address information and the MAC address of the server 4 whose IP address has been updated or the device newly connected to the network NW1. Then, the device information notification unit 213 of the base station 2 generates a device information notification frame including the IP address information and the MAC address information of the server 4 whose IP address has been updated or the device newly connected to the network NW1, and transmits the frame to the wireless communication device 1. As a result, when the IP address information of the server 4 is updated or when a new device is connected to the network NW1, the IP address information stored in the address storage unit 131 of the wireless communication device 1 is updated accordingly, so that the IP address information stored in the address storage unit 131 of the wireless communication device 1 is always kept as the latest IP address information. Therefore, when the IP address of the server 4 is updated or when a new device is connected to the network NW1, it is possible to prevent the updated IP address information of the server 4, or the IP address information and MAC address information of the newly connected device, from being stored in the address memory unit 131 of the wireless communication device 1 for a long period of time.

[0060] Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations of the embodiments. For example, the connection processing unit 111 of the wireless communication device 1 may include device information request flag information in a type of management frame other than an association request frame, such as a probe request frame or an authentication request frame, and transmit the frame to the base station 2.

[0061] In the embodiment, an example has been described in which the camera 3 and the wireless communication device 1 are separate entities, but this is not limited to this, and the communication system may also include a camera system in which the camera 3 and the wireless communication device 1 are housed in a single housing.

[0062] Furthermore, it has been explained that the policy memory unit 132 of the wireless communication device 1 stores either discard policy information or forward policy information as policy information indicating the policy for processing an ARP request frame when the IP address information included in the ARP request frame sent from the camera 3 is not present in the IP address information stored in the address memory unit 131. However, it is also possible to store both of these two types of policy information and allow the user of the wireless communication device 1 to select either one depending on the situation using a selection means such as a switch provided on the wireless communication device 1.

[0063] The various functions of the wireless communication device 1 and base station 2 according to the present invention can be realized using a computer system, rather than a dedicated system. For example, a program for executing the above operations may be stored on a non-transitory recording medium (such as a CD-ROM) that can be read by the computer system and distributed to a computer connected to the network, and the program may be installed in the computer system to configure the wireless communication device 1 and base station 2. The method for providing the program to the computer is arbitrary. For example, the program may be uploaded to a server on a communication line and distributed to the computer via the communication line.

[0064] Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to these. The present invention includes any combination of the embodiments and modifications, and any combination to which appropriate modifications have been made. [Industrial Applicability]

[0065] The present invention is suitable as a relay device having a bridge function for connecting a wired LAN to a wireless LAN. [Explanation of symbols]

[0066] 1: wireless communication device, 2: base station, 3: camera, 4: server, 101, 201: CPU, 102, 202: main memory, 103, 203: auxiliary memory, 106, 206: wireless module, 107, 207: wired communication I / F, 109, 209: bus, 111, 212: connection processing unit, 112: device information acquisition unit, 113: address identification unit, 114: address request acquisition unit, 115: address notification unit, 116, 211: address acquisition unit, 117, 214: frame acquisition unit, 118, 215: frame transmission unit, 121, 221: frame buffer, 131, 231: address storage unit, 132: policy information storage unit, 213: device information notification unit, NW1: network, NW2: wired communication path, NW3: wireless communication link

Claims

1. A communication system including a wireless communication device capable of communicating with a first device, and a base station that wirelessly communicates with the wireless communication device, The wireless communication device a connection processing unit that generates a management frame including device information request flag information indicating a request to the base station to transmit IP address information and MAC address information of a second device that can communicate with the base station, and transmits the management frame to the base station, thereby establishing a wireless connection with the base station; a device information acquisition unit that, upon receiving a device information notification frame transmitted from the base station and including the IP address information and the MAC address information of the second device, extracts the IP address information and the MAC address information included in the received device information notification frame; an address storage unit that stores the IP address information and the MAC address information of the second device extracted by the device information acquisition unit in association with each other; an address request acquisition unit that acquires an address request frame transmitted from the first device, the address request frame including the IP address information of the second device and requesting notification of MAC address information of the second device; an address specification unit that specifies, when any of the IP address information stored in the address storage unit matches the IP address information included in the acquired address request frame, the MAC address information that is associated with the IP address information included in the address request frame from the MAC address information stored in the address storage unit; an address notification unit that generates an address response frame including the specified MAC address information and transfers the frame to the first device; The base station a device information notification unit that, when acquiring the management frame transmitted from the wireless communication device, determines that the acquired management frame includes the device information request flag information, generates a device information notification frame including the IP address information and the MAC address information of the second device, and transmits the device information notification frame to the wireless communication device; Communication system.

2. the address notification unit discards the notification of the address response frame to the first device when the IP address information stored in the address storage unit does not match the IP address information included in the acquired address request frame. The communication system of claim 1 .

3. The wireless communication device a wireless communication device-side address acquisition unit that, when the IP address information stored in the address storage unit does not match the IP address information included in the acquired address request frame, transmits the address request frame to the base station, and acquires the address response frame that is transmitted from the base station and includes the MAC address information of the second device corresponding to the address request frame; When the address notification unit acquires the address response frame transmitted from the base station, the address notification unit transfers the acquired address response frame to the first device. The communication system of claim 1 .

4. The base station a base station-side address acquisition unit that acquires the IP address information and a MAC address of the second device when the IP address information of the second device is updated or when communication with the second device is newly enabled; the device information notification unit generates a device information notification frame including the acquired IP address information and MAC address information, and transmits the frame to the wireless communication device, even when the IP address information and the MAC address information of the second device whose IP address information has been updated or the second device that has newly become communicable are acquired. The communication system of claim 1 .

5. The wireless communication used for wireless communication between the wireless communication device and the base station is wireless communication in which the ratio of time that can be used for frame transmission per preset unit time is limited to a certain ratio. The communication system of claim 1 .

6. A wireless communication device capable of communicating with a first device and wirelessly communicating with a base station, a connection processing unit that generates a management frame including device information request flag information indicating a request to the base station to transmit IP address information and MAC address information of a second device that can communicate with the base station, and transmits the management frame to the base station, thereby establishing a wireless connection with the base station; a device information acquisition unit that, upon receiving a device information notification frame including the IP address information and the MAC address information of the second device transmitted from the base station, extracts the IP address information and the MAC address information included in the received device information notification frame; an address storage unit that stores the IP address information and the MAC address information of the second device extracted by the device information acquisition unit in association with each other; an address request acquisition unit that acquires an address request frame transmitted from the first device, the address request frame including the IP address information of the second device and requesting notification of MAC address information of the second device; an address specification unit that specifies, when any of the IP address information stored in the address storage unit matches the IP address information included in the acquired address request frame, the MAC address information that is associated with the IP address information included in the address request frame from the MAC address information stored in the address storage unit; an address notification unit that generates an address response frame including the identified MAC address information and transfers the frame to the first device; Wireless communication device.

7. A communication method for a communication system including a wireless communication device capable of communicating with a first device and a base station that wirelessly communicates with the wireless communication device, a step in which the wireless communication device generates a management frame including device information request flag information indicating a request to the base station to transmit IP address information and MAC address information of a second device that can communicate with the base station, and transmits the management frame to the base station, thereby establishing a wireless connection with the base station; When the base station acquires the management frame transmitted from the wireless communication device, if it determines that the acquired management frame includes the device information request flag information, it generates a device information notification frame including the IP address information and the MAC address information of the second device and transmits the device information notification frame to the wireless communication device; When the wireless communication device receives the device information notification frame transmitted from the base station, the wireless communication device extracts the IP address information and the MAC address information included in the received device information notification frame; storing, by the wireless communication device, the extracted IP address information and the MAC address information of the second device in association with each other; a step of the wireless communication device acquiring an address request frame transmitted from the first device, the address request frame including the IP address information of the second device and requesting notification of MAC address information of the second device; a step in which, when any of the IP address information stored in an address storage unit matches the IP address information included in the acquired address request frame, the wireless communication device identifies the MAC address information associated with the IP address information included in the address request frame from the MAC address information stored in the address storage unit; and a step of the wireless communication device generating an address response frame including the identified MAC address information and transferring the frame to the first device. Communication method.

8. Computer, a connection processing unit that generates a management frame including device information request flag information indicating that the management frame requests a base station to transmit IP address information and MAC address information of a second device that can communicate with the base station, and transmits the management frame to the base station, thereby establishing a wireless connection with the base station; a device information acquisition unit that, upon receiving a device information notification frame transmitted from the base station and including the IP address information and the MAC address information of the second device, extracts the IP address information and the MAC address information included in the received device information notification frame; an address storage unit that stores the IP address information and the MAC address information of the second device extracted by the device information acquisition unit in association with each other; an address request acquisition unit that acquires an address request frame that includes the IP address information of the second device and requests notification of MAC address information of the second device, transmitted from a first device; an address specifying unit that specifies, when any of the IP address information stored in the address storage unit matches the IP address information included in the acquired address request frame, the MAC address information that is associated with the IP address information included in the address request frame from the MAC address information stored in the address storage unit; an address notification unit that generates an address response frame including the identified MAC address information and notifies the first device of the generated address response frame; A program to function as a

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