JP2008263335A - Wireless lan system, access point device, and control method of wireless lan system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless LAN system capable of efficiently performing intermittent receiving operation of a wireless terminal set in power-saving mode in a multi-ESSID environment. <P>SOLUTION: An access point 10 includes a wireless communication section 105 which periodically transmits a beacon including an ESSID using a prescribed frequency channel, a beacon data generator 104 which periodically switches the ESSID included in the beacon without changing the frequency channel, and a data reception processor (a header converter 102 and a wired communication part 101) which relays reception data received from wireless terminals 20 and 21 to transfer destinations predetermined according to logical networks that the wireless terminals 20 and 21 belong to. The wireless terminals 20 and 21, each has a control unit 201 which performs control to receive a beacon including an ESSID indicative of the logical network that the wireless terminal itself belongs to intermittently at a period which is an integral multiple of a switching period of the ESSID at the access point 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless local area network (LAN) system including an access point device and at least one wireless terminal that performs wireless communication with the access point device.

  In a conventional wireless LAN system such as IEEE802.11b, a plurality of logical networks are identified by a network identifier called ESSID (Extended Service Set Identifier). That is, by setting a common ESSID for both the access point device and the wireless terminal, the access point device rejects a connection from a wireless terminal set with an ESSID different from that of the access point device and between the wireless terminals having the same ESSID. Communicate only with. Thereby, interference between networks with different ESSIDs can be avoided.

  Also, by setting a plurality of ESSIDs in one access point and associating each of the plurality of ESSIDs on the wireless LAN side with a plurality of VLAN IDs on the wired LAN side one-to-one, a plurality of networks having different ESSIDs A technique shared by both companies is known (see, for example, Patent Document 1). Such a technique is called multi-ESSID.

In addition, in order to reduce power consumption of a wireless terminal, a technique is known in which the operation of a wireless communication unit included in the wireless terminal is periodically suspended (see, for example, Patent Document 2). Such an operation mode of the wireless terminal is called a power saving mode. The wireless terminal set to the power saving mode receives these data intermittently rather than receiving all beacons and messages transferred from the access point.
JP 2007-28210 A JP 2002-300195 A

  In order to manage a plurality of logical networks having different ESSIDs, an access point corresponding to the multi-ESSID needs to transmit a beacon to each of the plurality of logical networks. As described above, when one access point configures a plurality of logical networks having different ESSIDs using a single frequency channel, the beacon transmission timing of the access point and the wireless terminal that associates with the access point is a beacon. However, there is a problem that the power saving mode operation of the wireless terminal does not function sufficiently because there is no regulation regarding the timing at which the wireless terminal should be received.

  The present invention has been made in view of the above-described problems, and is saved when one access point configures a plurality of logical networks having different network identifiers (ESSID, etc.) using a single frequency channel. An object of the present invention is to provide a wireless LAN system capable of efficiently performing intermittent reception operation of a wireless terminal set in a power mode.

  A wireless LAN system according to the present invention includes an access point device and at least one wireless terminal that performs wireless communication with the access point device, and the access point device further includes a logic to which the wireless terminal belongs. A beacon transmitter that periodically transmits beacon data including a network identifier that can identify a network using a predetermined frequency channel, and the network identifier included in the beacon data is kept the same as the frequency channel. A beacon data generation unit that periodically switches, and a data reception processing unit that relays reception data received from the wireless terminal to a transfer destination that is predetermined according to the logical network to which the wireless terminal belongs. Further, the wireless terminal intermittently receives the beacon data including the network identifier indicating the logical network to which the wireless terminal belongs at a cycle that is an integral multiple of the network identifier switching cycle of the access point device. The control part which controls is provided.

  Thus, in the wireless LAN system according to the present invention, the access point periodically switches the network identifier (such as ESSID) included in the beacon data. Further, the data received by the access point from the wireless terminal is relayed to a predetermined transfer destination according to the network identifier of the logical network to which the wireless terminal belongs. With such a configuration, a plurality of logical networks having different ESSIDs can be configured by using a single frequency channel by at least one access point. In addition, the frequency used can be improved by periodically switching the network identifier included in the beacon data while the access point remains the same frequency channel, and cell planning and carrier sense operations are easy. become.

  Further, the wireless terminal may not receive all the beacon data transmitted by the access point. That is, the wireless terminal only needs to receive beacon data transmitted toward the network having the network identifier set in itself. For this reason, the wireless terminal set to the power saving mode does not need to transition from the nap state to the awake state in order to receive beacon data including other network identifiers that are not related to the wireless terminal. Can be suppressed.

  According to the present invention, when one access point configures a plurality of logical networks having different network identifiers (ESSID, etc.) using a single frequency channel, the intermittent reception operation of the wireless terminal set in the power saving mode is efficiently performed. A well-executable wireless LAN system can be provided.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary for the sake of clarity.

Embodiment 1 FIG.
FIG. 1 shows a configuration of a wireless LAN system 1 according to the present embodiment. The wireless LAN system 1 includes an access point 10 and wireless terminals 20 and 21 that associate with the access point 10 and perform wireless data communication with the access point. Here, it is assumed that different ESSIDs are set for the wireless terminals 20 and 21. Specifically, the ESSID set in the wireless terminal 20 is “A”, and the ESSID set in the wireless terminal 21 is “B”.

  The VLAN switch 11 is connected to networks NW1 and NW2 to which different VLAN IDs are assigned. Specifically, the VLAN ID assigned to the network NW1 is “C”, and the VLAN ID assigned to the network NW2 is “D”. When the VLAN switch 11 transfers the data received from the networks NW1 and NW2 to the access point 10, the VLAN switch 11 adds a VLAN tag indicating the corresponding VLAN ID to the transmission data.

  The access point 10 has a wired LAN interface such as 100BASE-TX and is connected to the VLAN switch 11. In addition, the access point 10 has an ESSID-VLAN correspondence table that defines the correspondence between ESSID and VLANID, and the access point 10 transfers data received from the wireless terminals 20 and 21 to the VLAN switch 11. In this case, a VLAN tag indicating a VLAN ID associated with the ESSID to which the wireless terminal belongs is added to the transmission data. On the other hand, processing when data received from the VLAN switch 11 is transferred to the wireless terminal 20 or 21 is performed as follows. That is, if the data received from the VLAN switch 11 is unicast data, the data is transmitted to the wireless terminal specified by the destination address. If the data received from the VLAN switch 11 is broadcast data, the data is transmitted to the wireless terminal belonging to the ESSID associated with the VLAN ID (VLAN tag) assigned to the broadcast data.

  FIG. 2 is a block diagram showing the configuration of the access point 10. In FIG. 2, the wired communication unit 101 transmits and receives data to and from the VLAN switch 11. The header conversion unit 102 mutually converts a wired LAN header attached to communication data transmitted / received by the wired communication unit 101 and a wireless LAN header attached to communication data transmitted / received by the wireless communication unit 105 described later. . More specifically, the header conversion unit 102 refers to the ESSID-VLANID correspondence table 103 in which ESSID and VLANID are associated with each other, thereby converting between the ESSID on the wireless LAN side and the VLANID on the wired LAN side. I do.

  A specific example of the ESSID-VLANID correspondence table 103 is shown in FIG. The table of FIG. 4 describes the relationship between ESSID and VLAN ID corresponding to the configuration of FIG. Specifically, ESSID = A and VLANID = C are associated with each other, and ESSID = B and VLANID = D are associated with each other.

  Returning to FIG. 2, the beacon data generation unit 104 generates beacon data transmitted by the wireless communication unit 105 described later. The beacon data transmission cycle by the access point 10 is hereinafter referred to as a beacon interval. Further, the beacon data generation unit 104 periodically includes a DTIM (delivery traffic indication message) in the beacon data periodically transmitted at every beacon interval. The DTIM is information for notifying the wireless terminals 20 and 21 set in the power saving mode that there is data waiting for transmission. Hereinafter, beacon data including DTIM is referred to as a DTIM beacon. Further, the beacon generation unit 104 periodically switches the ESSID included in the beacon data in order to transmit beacon data corresponding to a plurality of ESSIDs.

  The wireless communication unit 105 performs wireless data transmission / reception with the wireless terminals 20 and 21 via the antenna 106.

  Next, the configuration of the wireless terminals 20 and 21 will be described with reference to FIG. FIG. 3 is a block diagram illustrating a configuration example of the wireless terminal 20. The control unit 201 acquires a descriptor generated by an upper layer control unit (not shown), controls the data buffer 202, the data processing unit 203, and the wireless communication unit 204 according to the acquired descriptor, and when the processing indicated by the descriptor is completed, To an upper layer processing unit (not shown). Here, the upper layer processing unit bears the upper layer of the wireless LAN communication protocol and is typically a computer provided with driver software for the wireless terminal 20. The descriptor is information related to data transmission / reception with the access point 10 and includes a storage location of transmission data, a transmission data size, a destination address, and the like. Furthermore, the control unit 201 controls establishment of an association with an access point, and sets the power saving mode of the wireless communication unit 204.

  The data buffer 202 is a buffer memory used for storing transmission data acquired from an upper layer processing unit (not shown) and storing received data received from the access point 10. The data processing unit 203 assembles a transmission data frame (MAC frame) and disassembles a reception data frame. The wireless communication unit 204 is a processing unit that performs wireless data transmission / reception with the access point 10 via the antenna 205, and transmits a transmission data frame input from the data processing unit 203 to the access point 10. The received data frame received from 10 is output to the data processing unit 203.

  Next, data transmission / reception timing between the access point 10 and the wireless terminals 20 and 21 will be described with reference to FIG. FIG. 5 shows the transmission timing of beacon data by the access point 10 and the timing at which the wireless terminals 20 and 21 in the power saving mode transition from the doze state to the awake state and receive beacon data. ing.

  In FIG. 5, a beacon 40 </ b> A and a DTIM beacon 41 </ b> A are beacon data transmitted to a wireless terminal belonging to the network of ESSID = A, that is, the wireless terminal 20. On the other hand, the beacons 40B and 41B are beacon data transmitted to the wireless terminal 21 belonging to the network of ESSID = B.

  In the example of FIG. 5, the switching period of the ESSID included in the beacon data is three times the beacon interval. That is, every time three pieces of beacon data are transmitted, the ESSID in the beacon data is switched from “A” to “B” or vice versa.

  In the example of FIG. 5, the DTIM interval is also three times the beacon interval. However, since the above-described ESSID switching is also performed, the transmission interval of the DTIM beacon 41A corresponding to ESSID = A and the transmission interval of the DTIM beacon 41B corresponding to ESSID = B are 6 times the beacon interval.

  When the beacon interval and DTIM interval of the access point 10 are adjusted as shown in FIG. 5, the wireless terminals 20 and 21 that associate with the access point 10 return from the nap state to the awake state in order to receive the beacon. The period (Listen Interval) is six times the beacon interval. Moreover, the timing (wake-up timing) at which the wireless terminals 20 and 21 transition to the awake state is determined by the transmission phases of the DTIM beacons 41A and 41B. That is, the wireless terminals 20 and 21 return from the nap state to the awake state at different timings.

  As described above, in the wireless LAN system 1 according to the present embodiment, the access point 10 periodically switches the ESSID included in the beacon data. In addition, data received by the access point 10 from the wireless terminals 20 and 21 is relayed to a transfer destination VLAN determined in advance according to the ESSID of the logical network to which the wireless terminal belongs. With such a configuration, a plurality of logical networks having different ESSIDs can be configured by using a single frequency channel by at least one access point 10.

  Further, the wireless terminals 20 and 21 do not have to receive all DTIM beacons transmitted by the access point 10. That is, the wireless terminals 20 and 21 need only receive the DTIM beacon transmitted toward the network of the ESSID set for itself. For this reason, the wireless terminals 20 and 21 set in the power saving mode do not need to transition to the awake state in order to receive the DTIM beacon including other ESSID unrelated to itself, and the power consumption of the wireless terminals 20 and 21 Can be effectively suppressed.

Example 1
Hereinafter, an embodiment in which the above-described wireless LAN system 1 is applied to a public wireless LAN service will be described with reference to FIGS. FIG. 6 is a configuration diagram of the wireless LAN system 1 according to the present embodiment. In the example of FIG. 6, the network NW1 is a network that can be accessed by a wireless terminal of a user who has not completed user registration for the public wireless LAN service. On the other hand, the network NW2 is a network that can be accessed by the wireless terminal of the user who has completed user registration of the public wireless LAN service.

  The network NW1 has a configuration in which a VLAN switch 11 and a registration server 14 are connected to a wired LAN 12 to which VLANID = C is assigned. The registration server 14 accepts registration of a user whose user registration has not been completed, and transmits a client electronic certificate to the wireless terminal of the newly registered user.

  The network NW2 has a configuration in which a VLAN switch 11, an authentication server 15, and a router 16 are connected to a wired LAN 13 to which VLANID = D is assigned. The authentication server 15 is specifically a RADIUS authentication server. The access point 10 supports an IEEE 802.1X authentication function and serves as an authenticator in the IEEE 802.1x authentication procedure. The router 16 is a communication device that connects the network NW2 to the Internet.

  Next, a user registration procedure and a user authentication procedure performed when providing the public wireless LAN service in this embodiment will be described. FIG. 7 is a flowchart showing a user registration procedure. First, in step S11, the ESSID of the wireless terminal 20 is set to “A”. In addition, a WEP (Wired Equivalent Privacy) key corresponding to the network with ESSID = A is set in the wireless terminal 20.

  In step S <b> 12, an association is established between the wireless terminal 20 and the access point 10 using the ESSID and WEP key set in the wireless terminal 20. In step S13, the wireless terminal 20 accesses the registration server 14, and a predetermined user registration procedure is performed. When the user registration procedure is completed, a client electronic certificate is transmitted from the registration server 14 to the wireless terminal 20 (step S14). The client electronic certificate includes a registered user name, expiration date information, and an electronic signature of a CA (Certificate Authority). When the reception of the client electronic certificate is completed, the connection between the wireless terminal 20 and the access point 10 is temporarily disconnected.

  Next, a user authentication procedure will be described using the flowchart of FIG. In step S21, the ESSID of the wireless terminal 20 is set to “B”. In step S <b> 22, an association is established between the wireless terminal 20 and the access point 10 using the ESSID set in the wireless terminal 20. In step S 23, an IEEE 802.1X authentication request is transmitted from the wireless terminal 20 to the access point 10, and the authentication server 15 authenticates the wireless terminal 20 through the access point 10. Specifically, under the data relay by the access point 10, the authentication server 15 and the wireless terminal 20 follow the authentication process using the EAP (Extensible Authentication Protocol) -TLS (Transport Layer Security) protocol, Mutual recognition by server electronic certificate may be performed.

  When the authentication in step S23 is successful, the communication encryption key is transmitted from the authentication server 25 to the wireless terminal 20 via the access point 10 (steps S24 and S25). At the same time, the access point 10 permits the wireless terminal 20 to connect to the network NW2. The communication encryption key may be a WEP key or a more reliable encryption key such as an AES (Advanced Encryption Standard) key.

  When the authentication in step S23 fails, the wireless terminal 20 is notified of a message indicating the authentication failure. The access point 10 blocks the connection of the wireless terminal 20 to the network NW2 (step S26).

  According to the configuration shown in the present embodiment, for example, when shifting from the current public wireless LAN service using only the ESSID and the WEP key to a new public wireless LAN service that performs highly reliable user authentication using IEEE802.1X, It is easy for users who use the current service to move to the new service. Further, according to the configuration shown in the present embodiment, it is possible to provide two public wireless LAN services with different authentication methods and encryption methods by one access point 10.

  Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention described above.

1 is a configuration diagram of a wireless LAN system according to an embodiment of the present invention. It is a block diagram of the access point apparatus concerning embodiment of this invention. It is a block diagram of the radio | wireless terminal concerning embodiment of this invention. It is a figure which shows an example of an ESSID-VLANID correspondence table. It is a figure which shows the data transmission / reception timing of the wireless LAN system concerning embodiment of this invention. It is a block diagram which shows the Example of the wireless LAN system concerning embodiment of this invention. It is a flowchart which shows operation | movement of the radio | wireless terminal concerning embodiment of this invention. It is a flowchart which shows operation | movement of the radio | wireless terminal concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless LAN system 10 Access point apparatus 12, 13 Wired LAN
14 Registration server 15 Authentication server 16 Router 20, 21 Wireless terminal 40A, 40B Beacon 41A, 41B DTIM beacon 101 Wired communication unit 102 Header conversion unit 103 SSID-VLANID correspondence table 104 Beacon data generation unit 105 Wireless communication unit 106 Antenna 201 Control unit 202 Data buffer 203 Data processing unit 204 Wireless communication unit 205 Antenna

Claims (8)

A wireless LAN system comprising an access point device and at least one wireless terminal that performs wireless communication between the access point device,
The access point device is
A beacon transmission unit that periodically transmits beacon data including a network identifier capable of identifying a logical network to which the wireless terminal belongs; using a predetermined frequency channel;
A beacon data generation unit that periodically switches the network identifier included in the beacon data while keeping the frequency channel the same;
A data reception processing unit that relays received data received from the wireless terminal to a predetermined transfer destination according to the logical network to which the wireless terminal belongs;
The wireless terminal is
A wireless LAN system comprising a controller that controls to intermittently receive the beacon data including the network identifier indicating the logical network to which the access point device belongs, at an integer multiple of the network identifier switching period by the access point device .   The intermittent reception cycle of the beacon data by the wireless terminal is a transmission cycle of beacon data including DTIM information indicating the existence of data waiting to be transmitted from the access point device to the wireless terminal. The wireless LAN system described in 1. An access point device that configures a wireless LAN with at least one wireless terminal and performs wireless communication with the wireless terminal,
A beacon transmission unit that periodically transmits beacon data including a network identifier capable of identifying a logical network to which the wireless terminal belongs; using a predetermined frequency channel;
A beacon data generation unit that periodically switches the network identifier included in the beacon data while keeping the frequency channel the same;
A data reception processing unit that relays received data received from the wireless terminal to a transfer destination determined in advance according to the logical network to which the wireless terminal belongs;
An access point device comprising:   The access point device according to claim 3, wherein a switching cycle of the network identifier included in the beacon data is twice or more a transmission cycle of the beacon data.   The switching cycle of the network identifier included in the beacon data is a cycle in which the wireless terminal in the power saving mode returns from the nap state to the awake state in order to intermittently receive data transmitted from the access point device. The access point device according to claim 3, wherein the access point device is determined accordingly.   The access point device according to any one of claims 3 to 5, further comprising a data transmission processing unit that switches an encryption processing procedure for transmission data to the wireless terminal in accordance with switching of a network identifier included in the beacon data. A control method of a wireless LAN system comprising an access point device and at least one wireless terminal that performs wireless communication between the access point device,
Periodically transmitting beacon data including a network identifier capable of identifying a logical network to which the wireless terminal belongs using a predetermined frequency channel from the access point device;
Periodically switching the network identifier included in the beacon data while keeping the frequency channel the same;
Relaying data received from the wireless terminal by the access point device to a predetermined transfer destination according to the logical network to which the wireless terminal belongs;
Control method.   Among the plurality of beacon data periodically transmitted from the access point device, the wireless terminal includes beacon data including a network identifier indicating a logical network to which the wireless terminal belongs, which is an integral multiple of the network identifier switching period. The control method according to claim 7, comprising a step of intermittently receiving at a cycle.

Images