This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2008-76282, filed on Mar. 24, 2008; the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a wireless base station, communication control method and a program storage medium storing a communication program for performing the communication control method.
2. Related Art
In a wireless LAN (Local Area Network) system compliant with the IEEE802.11 standard, a mobile station connects to a wireless network by specifying an identifier (SSID: Service Set Identifier) assigned to a group of a plurality of base stations. The system is designed such that the mobile station selects and determines a base station to which the mobile station is finally connected from among the base stations belonging to the SSID. For example, the scheme described in JP-A 07-87011(Kokai) that selects a base station of good reception electric field strength and the scheme described in JP-A 09-261711(Kokai) that selects a base station which is physically close to a mobile station using an interface (GPS or the like) for acquiring physical positions are schemes generally used.
However, the selection scheme using wireless propagation quality such as reception electric field strength might mistakenly select a base station of bad communication quality if wireless propagation quality drastically changes under the influences of an environment. For example, despite the fact that a system administrator conducts a careful site survey on a certain floor and installs a base station which is supposed to have good communication quality, if temporary wireless interference occurs at the moment a mobile station attempts to connect to a wireless network, the mobile station may end up being connected to a base station of bad communication quality installed on another floor.
On the other hand, the selection scheme using an interface (GPS or the like) that acquires physical locations allows connection to a base station that enables good communication quality to be stably obtained independently of variations in wireless propagation quality but involves a problem of increases in cost for introducing a new interface and cost for operation/maintenance thereof.
As described above, when a mobile station connects to a wireless network by specifying an SSID, the conventional scheme that uses wireless propagation quality has the problem of mistakenly connecting to a base station of bad communication quality. On the other hand, the scheme that selects a base station based on physical locations allows connection to an appropriate base station, but involves the problem of increasing introduction, operation and maintenance costs.
According to an aspect of the present invention, there is provided with a wireless base station, which is one of a plurality of base stations each forming a wireless area and communicating with a mobile station within the wireless area, comprising:
a reception unit configured to receive an connection request from a mobile station that exists within the wireless area;
an information acquirer configured to acquire connection history information indicating connection history to a base station which was connected by the mobile station in the past;
a condition storage configured to store a connection permission condition to permit connection with the mobile station;
a judgment unit configured to judge whether or not the connection permission condition is satisfied based on the connection history information; and
a reporting unit configured to report a message of connection permission to the mobile station when the connection permission condition is satisfied.
With reference now to the attached drawings, an embodiment of the present invention will be explained below.
In
As shown in
The base station A is provided with a connect request reception unit (a reception unit) 13 that receives a connect request from the mobile station, an connection history information acquirer (an information acquirer) 14 that acquires connection history information on the mobile station from which the connect request reception unit 13 has received the connect request from the connection history information database 12 of the connection history management server M, an connection permission/rejection judgment unit (a judgment unit) 15 that judges connectibility for the mobile station based on whether or not the acquired connection history information satisfies connection permission conditions managed by the connection permission condition database 11, an connection history information updater (an information updater) 16 that updates the connection history information on the mobile station whose connection has been permitted and uploads the connection history information to the connection history information database 12 of the connection history management server M and an connection permission reporting unit 17 that reports permission of connection or rejection of connection to the mobile station.
An example where the respective modules 11, 12, 13, 14, 15, 16 and 17 are configured as hardware has been explained, but the present invention is not limited to this, and the base station A or connection history management server M may also be adapted so as to provide the functions as software executed on a computer. In this case, software (communication program) is stored in a storage such as a hard disk or recording medium such as CD-ROM and can be read from this storage or recording medium and executed.
Suppose an initial state of the system is defined such that the mobile station H1 connects to the base station A for the first time (the mobile station H1 has not been connected to any base station before connecting to the base station A) and the mobile station H2 connects to the base station C for the first time. Therefore, in the initial state, the connection history information on the mobile station H1 and mobile station H2 managed by the connection history management server M is as shown in
Furthermore, as an example of the initial state of the system, suppose the connection permission condition in
Given the above described initial state, the operation of the base station B will be explained as an example.
First, a case where the mobile station H1 attempts to connect to the base station B will be considered.
First, the mobile station H1 sends a connect request to the base station B. The base station B receives the connect request (YES in S21) from the mobile station H1 and makes an inquiry to the connection history management server M (sends a message requesting the acquisition of connection history information) and thereby acquires the connection history information of the mobile station Hi shown in
Next, the base station B refers to the connection permission condition in
Next, the base station B updates the connection history information acquired for the mobile station Hi by adding the latest entry (base station B) thereto and uploads the updated connection history information to the connection history management server M (S24). That is, the base station B sends an update request message requesting an update of the connection history information of the mobile station H1 to the connection history management server M so as to include the base station B as the latest connection destination.
Finally, connection permission is reported to the mobile station H1 (S25). In this way, the connection between the mobile station H1 and the base station B is established and handoff can be realized.
Next, consider a case where the mobile station H2 attempts to connect to the base station B.
First, the mobile station H2 sends a connect request to the base station B. Next, the base station B receives the connect request (YES in S21), makes an inquiry to the connection history management server M (sends a message requesting the acquisition of connection history information) and thereby acquires the connection history information of the mobile station H2 shown in
Next, the base station B refers to the connection permission condition in
This makes it possible to realize handoff control that does not allow the connection between the mobile station H2 and the base station B to be established.
Hereinafter, an embodiment will be shown in consideration of physical locations of living rooms or the like more specifically.
Here, the administrator sets the inclusion of the base station C as the base station immediately before handoff in the connection history information in the connection permission condition of the base station A and sets the inclusion of the base station D as the base station immediately before handoff in the connection history information in the connection permission condition of the base station B.
Assume a case where the mobile station H passes through the entrance A and enters the living room A. When passing through the entrance A, the mobile station H attempts to connect to the base station C. Upon receiving a connect request, the base station C acquires connection history information of the mobile station H from the connection history management server M, adds the base station C to the connection history information as the latest entry and uploads the connection history information after the addition to the connection history management server M again. Next, the mobile station H enters the living room A. In this case, the connection history information of the mobile station H satisfies the connection permission condition of the base station A (see
Like
Here, the administrator sets a condition of requesting the inclusion of connection to the base station C in the connection history information as the connection permission condition of the base stations A1, A2 and A3 and sets a condition of requesting the inclusion of connection to the base station D in the connection history information as the connection permission condition of base stations B1, B2 and B3.
On the other hand, no connection permission condition is set in the base station C and base station D. That is, suppose connection to the base station C and base station D is permitted unconditionally.
Assume a case where the mobile station H passes through the entrance A and enters the living room A. When passing through the entrance A, the mobile station H attempts to connect to the base station C. Upon receiving the connect request, the base station C acquires connection history information of the mobile station H from the connection history management server M, adds the base station C to the connection history information as the latest entry and uploads the connection history information after the addition to the connection history management server M again. Next, the mobile station H enters the living room A. In this case the connection history information of the mobile station H satisfies the connection permission conditions of the base stations A1, A2 and A3, but does not satisfy the connection permission conditions of the base stations B1, B2 and B3. This ensures that the mobile station H can only connect to A1, A2 and A3 of good communication quality.
Here, the administrator further adds a condition of permitting connection when connection in the order of “base station D→base station C” is included in the connection history information and a condition of not permitting connection when connection in the order of “base station C→base station D” is included in the connection history information to the connection permission condition in
Here, in
Assume a case where the mobile station H passes through the entrance A and directly enters the living room A. When passing through the entrance A, the mobile station H attempts to connect to the base station C. Upon receiving the connect request, the base station C acquires connection history information of the mobile station H from the connection history management server M, adds the base station C to the connection history information as the latest entry and uploads the connection history information after the addition to the connection history management server M.
Next, the mobile station H enters the living room A. In this case, the connection history information of the mobile station H satisfies the connection permission conditions of the base stations A1, A2 and A3, but does not satisfy the connection permission conditions of the base stations B1, B2 and B3. Therefore, the mobile station H can reliably connect to only A1, A2 and A3 of good communication quality.
Assume a case where the mobile station H moves from the living room B to the living room A. The mobile station H attempts to connect to the base station D when passing through the entrance B. The base station D which has received the connect request acquires connection history information of the mobile station H from the connection history management server M, adds the base station D to the connection history information as the latest entry and uploads the connection history information after the addition to the connection history management server M. Next, the mobile station H attempts to connect to the base station C when passing through the entrance A. The base station C which has received the connect request acquires the connection history information of the mobile station H from the connection history management server M, adds the base station C to the connection history information as the latest entry and uploads the connection history information after the addition to the connection history management server M.
Next, the mobile station H enters the living room A. In this case, since the connection history information of the mobile station H satisfies the connection permission condition in
In this embodiment, the connection history management server M connected to the network 1 manages connection historys of the mobile station, but the mobile station itself can also manage the connection history information instead of installing the connection history management server M.
As shown in
The connect request reception unit 13 of the base station receives a connect request from the mobile station H, the connection history information acquirer 14 acquires the connection history information of the mobile station H from the mobile station H which has issued the connection request from the connection history information database 12 of the mobile station H. When connection is permitted by connection permission/rejection judgment unit 15, connection history information updater 16 updates the connection history information by adding the base station to which connection is permitted and uploads the updated connection history information to connection history information database 12 of the mobile station H. That is, the base station B sends to the mobile station H an update request message for requesting an update of the connection history information so as to include the base station B as the latest connection destination.
The embodiments of the present invention described so far are not limited to the above described contents, but can be modified and expanded in various ways. Some examples thereof will be shown hereunder.
Instead of using an connection permission condition with which traffic control priority (e.g., access category) is associated to judge connection permission or rejection, it is also possible to use the connection permission condition only for traffic priority control. For example, it is possible to unconditionally permit connection to a mobile station and perform traffic priority control based on a connection permission condition associated with priority.
As described so far, the embodiment of the present invention performs connection control with a handoff destination based on histories of connections to a mobile station and a base station and thereby allows the mobile station to reliably connect to an appropriate base station while minimizing the introduction, operation or maintenance cost.
Number | Date | Country | Kind |
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2008-76282 | Mar 2008 | JP | national |