JP2002185458A - Wireless LAN system and terminal - Google Patents

Abstract

(57) [Problem] To improve the communication efficiency of the entire system in a wireless LAN system. An access point includes a first storage unit that stores the number of connected terminals, and a first threshold setting unit that sets a first threshold value that is an upper limit number of connectable terminals.
23 is compared with the number of connected terminals stored in the first storage unit and the first threshold set in the first threshold setting unit, and it is determined that the number of connected terminals exceeds the first threshold A terminal connection control unit 1121 for issuing a connection switching instruction to another access point 12 to at least one of the connected terminals 21 to 2n, and receiving the connection switching instruction from the terminal connection control unit. 2n searches for another connectable access point based on a radio wave received from another access point, and switches the wireless connection to the other access point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless LAN system, and more particularly, to dynamically controlling a connection between a terminal and an access point in order to realize efficient data communication and low power consumption in a wireless LAN system. About technology.

[0002]

2. Description of the Related Art In order for a terminal performing wireless communication to connect to a backbone network, it must first connect to an access point. When there are a plurality of access points within the range of radio waves, it is common to connect to the access point with the highest received radio wave intensity from the viewpoint of communication speed and communication quality.

FIG. 14 is a schematic diagram showing a schematic configuration of a conventional wireless LAN system. A plurality of terminals 2 are connected to an access point 11 connected to the wired network 3.
1, 22, 23 and 24 are connected. No terminal is connected to the access point 12 connected to the wired network 3. In this way, each terminal determines which access point to connect to, and is allowed up to the limit of the access point.

[0004]

When an access point to be connected is determined based on the received signal strength, if there are many terminals near a specific access point, connections to that access point are concentrated. Since the traffic that can be processed by one access point is limited,
As shown in FIG. 14, when the access point 11 performs data transfer with a plurality of terminals 21, 22, 23, and 24 in a time sharing manner, the communication speed of each terminal decreases, and the transfer capability of each terminal decreases. Resulting in. However, the wired network 3, which is the backbone network, can process much more data than the amount of communication that can be processed by the access point, so that the overall system becomes inefficient.

[0005] When the number of terminals relative to the access point is small, the number of connections to the access point is reduced.
Some access points have extra transfer capacity. Accordingly, an unnecessary number of access points are in operation, and wasteful power is consumed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a wireless LAN system in which communication efficiency of the entire system is improved and power consumption is reduced, and a terminal suitable for the wireless LAN system. It is in.

[0007]

To achieve the above object, a first wireless LAN system according to the present invention comprises a wired backbone network, a plurality of access points connected to the backbone network, and an access point. A wireless LAN system having a plurality of terminals that access a backbone network by performing wireless connection, wherein each of the plurality of access points is connected to a first storage unit that stores the number of connected terminals. 1st which is the maximum number of terminals
A first threshold setting unit that sets the threshold of the number of connected terminals, and compares the number of connected terminals stored in the first storage unit with the first threshold set in the first threshold setting unit. A terminal connection control unit that issues a connection switching instruction to another access point to at least one of the terminals to be connected when it is determined that the value exceeds the first threshold, and the connection switching from the terminal connection control unit is performed. The terminal receiving the instruction searches for another connectable access point based on the radio wave received from the other access point, and switches the wireless connection to the other access point.

According to this first wireless LAN system,
The load on the access point where connections are concentrated can be reduced, and the transfer capability of the terminal connected to it and the terminal that has switched the connection to another access point can be increased.

In order to achieve the above object, a second wireless LAN system according to the present invention provides a wired backbone network, a plurality of access points connected to the backbone network, and wireless connection with the access points. A wireless LAN system including a plurality of terminals that access a backbone network, wherein each of the plurality of access points is a first storage unit that stores the number of connected terminals, and a maximum number of connectable terminals. A first threshold setting unit that sets a first threshold, a second storage unit that stores information about another access point connected to the backbone network, which is acquired via the backbone network, and a first storage The number of connected terminals is compared with the first threshold set in the first threshold setting unit, and the number of connected terminals is compared with the first threshold set in the first threshold setting unit.
Is determined, the connection switching instruction to another access point is issued to at least one of the connecting terminals, and the access point information stored in the second storage unit is notified. With a terminal connection control unit, the terminal having received the connection switching instruction and the access point information from the terminal connection control unit determines another connectable access point based on the access point information,
The wireless connection is switched to the other access point.

According to the second wireless LAN system,
An access point with a high concentration of terminal connections can use a wired network to search for other access points on the network and quickly collect information needed to connect to other access points. , The terminal that has received the connection switching instruction eliminates the need to search for another access point by itself, and selects an access point to switch connection immediately based on information of another access point wirelessly transmitted from the access point. -Since the connection can be determined, the connection can be switched efficiently.

[0011] To achieve the above object, a third wireless LAN system according to the present invention provides a wired backbone network, a plurality of access points connected to the backbone network, and wireless connection with the access points. A wireless LAN system having a plurality of terminals accessing a backbone network, wherein each of the plurality of access points is a first storage unit for storing the number of connected terminals, and an upper limit number of connectable terminals. A first threshold setting unit for setting a first threshold, and a terminal corresponding to each of the plurality of terminals, the terminal corresponding to information of another connectable access point obtained from another connectable access point via a wireless connection. The second storage unit, which is stored in association with the storage unit, compares the number of connected terminals stored in the first storage unit with the first threshold set in the first threshold setting unit. And, if the number of connection terminals has exceeded a first threshold value, stored in the second storage unit,
Based on information on other connectable access points associated with the terminal, determine a terminal that performs connection switching to another connectable access point, and, for the terminal that performs the connection switch, another connectable access point. A terminal connection control unit for issuing a connection switching instruction to an access point.

According to the third wireless LAN system,
The access point where terminal connections are concentrated determines the terminal and access point with the best connection relationship based on the information of connectable access points collected from each terminal, and switches connection to that terminal Since the instruction is issued, the terminal that has switched the connection can access the wired network via the new access point without reducing the communication speed.

[0013] In the third wireless LAN system, the information on the other connectable access points includes the number of terminals connected to the other connectable access points, and the terminal connection control unit determines that the number of connected terminals is the smallest. It is preferable to determine a terminal that can be connected to a small number of other access points as a terminal that performs connection switching.

According to this configuration, the terminal that has performed the switching is
The most data transfer opportunity can be obtained, and the best transfer capability can be secured.

[0015] In the third wireless LAN system, the information of the other connectable access points includes the radio wave intensity received from the other connectable access points, and the terminal connection control unit determines that the radio wave intensity is the highest. It is preferable to determine a terminal that can be connected to another access point as a terminal that performs connection switching.

According to this configuration, the terminal that has performed the switching is
A connection with good conditions in terms of communication speed and communication quality can be obtained.

Further, in the third wireless LAN system, the information of another connectable access point includes transmission line distortion for the other connectable access point,
It is preferable that the terminal connection control unit determines a terminal that can be connected to another access point having the smallest transmission path distortion as a terminal that performs connection switching.

According to this configuration, the terminal that has performed the switching is
A connection with good conditions in terms of communication speed and communication quality can be obtained.

In the first to third wireless LAN systems, the terminal connection control unit includes a second threshold value setting unit for setting a second threshold value which is a lower limit number of connectable terminals, and a first storage unit. Is compared with the second threshold set in the second threshold setting unit, and the number of connected terminals is set to the second
If it is determined that the threshold value is less than the threshold value, a connection switching instruction to other access points is issued to all connected terminals, and after connection switching of all terminals is completed, the necessary minimum functions of the access point It is preferable to set the power save mode in which only the power save mode is activated.

According to this configuration, the access point can be used efficiently, and the power consumption can be reduced.

To achieve the above object, a terminal according to the present invention is a terminal in the first to third wireless LAN systems, and the terminal is a wireless transmission / reception unit for wirelessly communicating with an access point. And a terminal control unit that controls access to a wired network via a wireless transmission / reception unit and an access point, and controls connection switching to another access point in accordance with an instruction from the access point. I do.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 is a schematic diagram showing a schematic configuration of a wireless LAN system according to an embodiment.

In FIG. 1, a plurality of terminals 2 are connected to an access point 11 connected to a wired network 3.
Connections of 1, 22, 23 and 24 are concentrated. In this case, the access point 11 transmits, for example, to the terminal 24, the access point 1 that is currently performing the connection 24A.
1 issues a connection switching instruction 4 to another access point 12. The terminal 24 that has received the connection switching instruction 4 receives the radio wave 5 transmitted from another access point 12, and if it can determine that the access point is a connectable access point based on the intensity of the radio wave 5, the terminal 24 transmits to the access point 12. The connection switching 6 of the access point 12 is performed, and the connection 24B with the access point 12 is performed.

As a result, the number of terminals connected to the access point 11 decreases, and the terminals 21, 2
The same applies to the terminal 24 whose connection has been changed to the access point 12, and the communication efficiency can be improved as a whole system.

FIG. 2 is a block diagram showing a detailed configuration of the wireless LAN system of FIG.

In FIG. 2, the access point 11
Wired transmitting / receiving unit 1 for connecting to wired network 3
11, a control unit 11 that controls data transfer between the wired network 3 and each terminal and controls the number of connected terminals
2, and a wireless transmission / reception unit 113 for performing wireless communication with each terminal. Although not shown, the access point 12 has the same configuration as the access point 11.

The control unit 112 includes a terminal connection control unit 1121 for controlling connection with a terminal, a connection terminal number storage unit 1122 for storing the number of connected terminals, and a connection number for setting the maximum number of terminals. And a threshold setting unit 1123.

The access point 11 has a plurality of terminals 2
1, 2n are connected. Each terminal includes a wireless transmission / reception unit 211 for performing wireless communication with the access points 11 and 12, and a control unit 212 for performing data transfer control with the access points 11 and 12 via the wireless transmission / reception unit. It has a similar configuration.

Next, the operation of the wireless LAN system according to the present embodiment will be described together with a flowchart showing the procedure for switching the terminal connection in the normal operation mode in FIG.

When a certain terminal 21 starts operating (step 312) while the access point 11 is operating (step 300), a connection 21A is made wirelessly with the access point 11 to access the wired network 3 (step 301). ). At this time, the terminal connection control unit 11
In step 21, the number N of connected terminals is counted, and the counted number N of connected terminals is stored in the connected terminal number storage unit 1122 (step 302).

Next, in the terminal connection control unit 1121,
The number of connection terminals N stored in the number-of-connection-terminals storage unit 1122 and the number-of-connections threshold K set in the number-of-connections-value setting unit 1123
Is performed (step 303), and as a result, if the number N of connected terminals does not exceed the threshold value K of the number of connections (No), connection with another terminal is performed.

Subsequently, when the other terminals 22,..., 2n start operating and start the connection with the access point 11, and the number N of connected terminals exceeds the threshold K of the number of connections (determination in step 303). Yes), access point control unit 1
12, the terminal connection control unit 1121 randomly selects a terminal, determines a terminal (terminal 2n in FIG. 2) to perform connection switching (step 304), and issues an access point connection switching instruction 4 (step 304). 305).

When the terminal 2n receives the connection switching instruction 4 (Yes in step 313), the terminal 2n searches for another access point (the access point 12 in FIG. 2) based on the received radio wave intensity or the like (step 314). Connection 2n
A connection switching 6 is performed from the access point 11 performing A to the access point 12 (step 31).
5) Connect 2 nB to the access point 12.

After the connection switching is completed (Yes in the judgment of step 306), the access point 11 subtracts 1 from the number N of connected terminals (step 307) and compares it with the threshold K of the number of connections (step 308). . If the result of the comparison in step 308 is that the number N of connected terminals still exceeds the connection threshold K (Yes), steps 304 to 3
08 is repeated, and when the number N of connected terminals becomes equal to or smaller than the connection threshold K (No in the determination of Step 308), Step 30
The process branches to 1 to prepare for connection with a new terminal.

(Second Embodiment) In the first embodiment,
The terminal that has received the connection switching instruction determines a change destination access point based on radio waves and information received from another access point. For this reason, a waiting time for receiving the transmission radio waves from the neighboring access points occurs, which is not efficient. Therefore, a second embodiment for solving such a problem will be described below.

FIG. 4 is a schematic diagram showing a schematic configuration of a wireless LAN system according to a second embodiment of the present invention.

In FIG. 4, the access point 11 that has been determined to have a concentrated connection is connected to another access point 1 existing on the network through the wired network 3.
Gather information about 2,13. Next, the access point 11 collects the other access points 12, 13 collected.
To the terminal 24 that has issued the access point connection switching instruction 4. Based on the information 12I and 13I of the other access points 12 and 13 sent from the access point 11, the terminal 24 determines the access point 12 as a new access point to be connected.
To access point 12 from the current connection 24A.
Connection switching 6 is performed on the connection 24B to the connection.

FIG. 5 is a block diagram showing a detailed configuration of the wireless LAN system of FIG. In FIG. 5, the same components as those in the first embodiment shown in FIG.

As shown in FIG. 5, in the second embodiment,
In addition to the configuration of the first embodiment, the access point control unit 112 includes an access point information storage unit 1124 that stores information on other access points 12 and 13 on the wired network 3. Information stored in the access point information storage unit 1124 is sent to the terminal that issued the connection switching instruction via the terminal connection control unit 1121 and the wireless transmission / reception unit 113.

Next, the operation of the wireless LAN system according to the present embodiment will be described together with a flowchart showing the procedure for switching the terminal connection in the normal operation mode in FIG. In FIG. 6, the same steps as those in the first embodiment in FIG.

The second embodiment shown in FIG. 6 is different from the first embodiment shown in FIG. 3 in that a connection switching terminal is selected and determined in an access point processing step 304, a connection switching instruction issuance step 305, The step 313 of accepting a connection switching instruction in the processing at the terminal and the step 314 of searching for another access point are deleted, and the step 600 of collecting and storing other access point information in the processing at the access point issuance of the connection switching instruction. This is provided with a step 601 for notifying other access point information and a step 602 for receiving a connection switching instruction / other access point information in processing at the terminal.

If it is determined in step 303 that the number N of connected terminals has exceeded the threshold number K of connections (Yes), the access point 11 transmits information such as ID numbers of the other access points 12 and 13 on the wired network 3. Are collected, and information on the other access points 12 and 13 is stored in the access point information storage unit 1124 (step 60).
0).

Next, the terminal connection control unit 1121 issues a connection switching instruction to the terminal 2n selected at random, and notifies the other access point information 4 collected (step 601). When receiving the connection switching instruction and the other access point information (Yes in the determination of step 602), the terminal 2n selects and determines, for example, the access point 13 as the access point for performing the connection switching based on the other access point information. And the current connection is 2nA
Is performed (step 315), and 2 nB of connection to the access point 13 is performed.

As described above, according to the present embodiment, there is no need for the terminal that has received the connection switching instruction to search for another access point by itself, and the connection switching is immediately performed based on the other access point information. Since the access point to be performed can be selected and determined, the connection can be switched efficiently.

(Third Embodiment) In the first and second embodiments, an access point with a concentrated connection determines a terminal that issues an access point switching instruction. In this case, if a connection switching instruction is issued to a terminal having only an access point with poor connection conditions, the connection state of the terminal that has received the connection switching instruction may be deteriorated, which may cause a reduction in communication speed. Therefore, a third embodiment for solving such a problem will be described below.

FIG. 7 is a schematic diagram showing a schematic configuration of a wireless LAN system according to the third embodiment of the present invention.

In FIG. 7, the terminals 21 and 22 connected to the access point 11 where connection is concentrated are transmitted by radio waves 12A output from the access point 12 existing in the vicinity.
Is received, and the terminal 23 connected to the access point 11 is connected to the access points 13 and 1 existing in the vicinity.
4 receives the radio waves 13A and 14A respectively output from the terminal 4 and sends information 15 relating to connectable access points to the current access point 11.

The access point 11 excludes the terminals 21 and 22 that can be connected to only one access point 12 based on the information 15 sent from each terminal.
A terminal 23 connectable to any one of the three access points 13 and 14 is selected and determined, and an access point connection switching instruction 16 is issued to the terminal 23.

Next, the terminal 23 selects and determines one of the two access points 13 and 14 on the basis of the access point information, for example, the access point 13 and changes the access point 1 from the current connection 23A.
The connection switch 6 is executed for the connection 23B to the connection 3B. Thus, the terminal 23 can connect to the new access point 13 under good connection conditions.

FIG. 8 is a block diagram showing a detailed configuration of the wireless LAN system of FIG. In FIG. 8, the same components as those in the first embodiment shown in FIG.

As shown in FIG. 8, in the third embodiment,
In addition to the configuration of the first embodiment, the access point 11
The control unit 112 includes an access point information storage unit 1125 for each terminal that stores information on connectable access points collected from each of the terminals 21,..., 2n.

Next, the operation of the wireless LAN system according to the present embodiment will be described together with a flowchart showing the procedure for switching the terminal connection in the normal operation mode in FIG. In FIG. 10, the same steps as those in the first embodiment in FIG.

If it is determined in step 303 that the number N of connected terminals has exceeded the threshold value K of the number of connections (Yes), the access point 11 issues a connectable access point information collection instruction 80 to all connected terminals. (Step 1000). When each terminal receives the information collection instruction 80 (Yes in step 1003), the radio waves 81 transmitted from the neighboring access points 12, 13, and 14 are transmitted.
, And a connectable peripheral access point 12,
Information such as the number of connected terminals 13 and 14, radio wave intensity, and transmission line distortion level is collected (step 1004), and the information is transmitted to the currently connected access point 11 (step 1005).

When the access point 11 receives the information on the connectable access points for each terminal (Yes in the judgment in step 1001), the access point 11
The terminal-specific access point information storage unit 1125 of FIG.
Is stored as a data table as shown in FIG.

Next, the access point 11 determines the combination of the number of connected terminals, the radio field intensity, and the transmission line distortion level, which are information on the connectable access points 12, 13, and 14 to the terminals 21,. Terminal (terminal 2n) and access point (access point 13) having the connection condition with the best condition
(Step 1002), and issues a connection switching instruction 4 to the corresponding access point 13 to the terminal 2n (step 305).

Upon receiving the connection switching instruction from the access point 11, the terminal 2n (Y in step 1006)
es), the connection is switched to the access point 13 (step 315).

As described above, according to the present embodiment, an access point with a concentrated connection can access a terminal having the best connection relationship based on information on connectable access points collected from each terminal. Determine the points,
Since the connection switching instruction is issued to the terminal, the terminal that has switched the connection can access the wired network via the new access point without lowering the communication speed.

(Fourth Embodiment) FIG. 11 is a schematic diagram showing a schematic configuration of a wireless LAN system according to a third embodiment of the present invention.

In FIG. 11, when the number of terminals connected to the access point 12 is as small as that of the terminal 22, and the data transfer capability at the access point 11 has a margin, the access point 12 Issue instruction 17. The terminal 22 that has received the access point switching instruction 17 executes the connection switching 18 from the access point 12 that is currently performing the connection 19 to the access point 11, and performs the connection 20 with the new access point 11.

As a result, since there are no terminals connected to the access point 12, the access point 12 enters the power save mode, which leaves only necessary minimum functions. As a result, access points can be used efficiently, and power consumption can be reduced.

FIG. 12 is a block diagram showing a detailed configuration of the wireless LAN system of FIG. In FIG. 12, the same components as those of the first embodiment shown in FIG.

As shown in FIG. 12, in the fourth embodiment, in addition to the configuration of the first embodiment, the control unit 112 of the access point 11 includes a connection number lower limit threshold for setting a lower limit of the number of terminal connections. A setting unit 1126 is provided. The connection number threshold setting unit 1123 that sets the upper limit of the number of connectable terminals in the first to third embodiments is referred to as a connection number upper threshold setting unit 1123 in this embodiment.

Next, the operation of the wireless LAN system according to the present embodiment will be described together with a flowchart showing the procedure for switching the terminal connection in the power save mode in FIG. In FIG. 13, the same steps as those in the first embodiment of FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

Upon entering the processing routine in the power save mode (step 1300), the access point 12
The number of connected terminals N is compared with the lower limit threshold L of the number of connected terminals (step 1301). If the result of the comparison in step 1301 is that the number N of connected terminals is equal to or greater than the lower limit threshold L for the number of connections (No),
Moving to step 300, the normal operation mode of the access point is entered, as shown in FIGS.

On the other hand, as a result of the comparison in step 1301,
When the number N of connected terminals is smaller than the lower limit threshold L for the number of connections (Y
es), the access point 12 issues a connection switching instruction to all connected terminals (only the terminal 22 in FIGS. 11 and 12) (step 305).

Then, the access point 12 completes the switching of all the terminals to be connected (Yes in the judgment of step 306), and confirms that there are no more connected terminals (Yes in the judgment of step 1302). (Step 1303).

[0068]

As described above, according to the present invention,
By dynamically switching the connection between the access point and the terminal based on the conditions of the terminal connected to the access point, efficient data transfer can be realized in the entire system.

Further, in an access point with a small number of connected terminals, an instruction to switch the access point is issued to the connected terminal, so that the connection is changed to another access point, and the access point with no connection to the terminal is changed. Power consumption can be reduced by setting the power save mode using only the necessary minimum functions.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a wireless LAN system according to a first embodiment of the present invention;

FIG. 2 is a block diagram showing a detailed configuration of the wireless LAN system of FIG. 1;

FIG. 3 is a flowchart showing a procedure for switching a terminal connection in a normal operation mode according to the first embodiment of the present invention;

FIG. 4 is a schematic diagram showing a schematic configuration of a wireless LAN system according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a detailed configuration of the wireless LAN system of FIG. 4;

FIG. 6 is a flowchart showing a procedure for switching a terminal connection in a normal operation mode according to the second embodiment of the present invention;

FIG. 7 is a schematic diagram showing a schematic configuration of a wireless LAN system according to a third embodiment of the present invention.

FIG. 8 is a block diagram showing a detailed configuration of the wireless LAN system of FIG. 7;

9 is an access point information storage unit 1 for each terminal shown in FIG. 8;
The figure which shows the content of the data table stored in 125

FIG. 10 is a flowchart showing a procedure for switching a terminal connection in a normal operation mode according to the third embodiment of the present invention;

FIG. 11 shows a wireless LAN according to a fourth embodiment of the present invention.
Schematic diagram showing the schematic configuration of the system

FIG. 12 is a block diagram showing a detailed configuration of the wireless LAN system in FIG. 11;

FIG. 13 is a flowchart illustrating a procedure for switching a terminal connection in a power save mode according to a fourth embodiment of the present invention;

FIG. 14 is a schematic diagram showing a schematic configuration of a conventional wireless LAN system.

[Explanation of symbols]

 11, 12, 13, 14 access point 111 wired transmission / reception unit 112 access point control unit 1121 terminal connection control unit 1122 connected terminal number storage unit 1123 connection number threshold setting unit (connection upper limit threshold setting unit) 1124 access point information storage unit 1125 Terminal-specific access point information storage unit 1126 Connection number lower limit threshold setting unit 113 Wireless transmission / reception unit 21, 22, 23, 24, 2n terminal 211 Terminal wireless transmission / reception unit 212 Terminal control unit 3 Wired network 4 Connection switching instruction

Claims (8)

[Claims] 1. A wireless LAN system having a wired backbone network, a plurality of access points connected to the backbone network, and a plurality of terminals accessing the backbone network by making a wireless connection with the access point. Each of the plurality of access points includes a first storage unit that stores the number of connected terminals, a first threshold setting unit that sets a first threshold value that is a maximum number of connectable terminals. Comparing the number of connected terminals stored in the first storage unit with a first threshold set in the first threshold setting unit, and determining that the number of connected terminals exceeds the first threshold And a terminal connection control unit for issuing a connection switching instruction to another access point to at least one of the terminals to be connected, wherein the connection switching from the terminal connection control unit is performed. Terminal that received indicates a wireless LAN system, characterized in that search for other access points that can be connected on the basis of the radio wave received from the other access points, switches the radio connection to the other access points. 2. A wireless LAN system including a wired backbone network, a plurality of access points connected to the backbone network, and a plurality of terminals that access the backbone network by making a wireless connection with the access point. Each of the plurality of access points includes a first storage unit that stores the number of connected terminals, a first threshold setting unit that sets a first threshold value that is a maximum number of connectable terminals. A second storage unit that stores information about another access point connected to the backbone network, which is acquired via the backbone network, and the number of connection terminals stored in the first storage unit, When comparing with the first threshold set in the first threshold setting unit and judging that the number of connected terminals exceeds the first threshold, the terminal to be connected is determined. A terminal connection control unit that issues a connection switching instruction to another access point and notifies the access point information stored in the second storage unit to at least one of The terminal receiving the connection switching instruction and the access point information from the connection control unit determines another connectable access point based on the access point information, and switches the wireless connection to the other access point. Characteristic wireless LAN system. 3. A wireless LAN system having a wired backbone network, a plurality of access points connected to the backbone network, and a plurality of terminals that access the backbone network by making a wireless connection with the access point. Each of the plurality of access points includes a first storage unit that stores the number of connected terminals, a first threshold setting unit that sets a first threshold value that is a maximum number of connectable terminals. A second storage unit that stores information on the other connectable access points obtained by each of the plurality of terminals from another connectable access point via a wireless connection in association with a corresponding terminal, The number of connected terminals stored in the first storage unit is compared with a first threshold set in the first threshold setting unit, and the number of connected terminals is set to the first threshold. If it is determined that the threshold value has been exceeded, connection switching to the other connectable access point is performed based on the information of the other connectable access point associated with the terminal, which is stored in the second storage unit. Is determined, and for the terminal performing the connection switching,
A wireless LAN system comprising: a terminal connection control unit that issues a connection switching instruction to the another connectable access point. 4. The information of the other connectable access points includes the number of terminals connected to the other connectable access points, and the terminal connection control unit determines that the number of the connected terminals is the smallest. 4. The wireless LAN system according to claim 3, wherein a terminal connectable to the access point is determined as a terminal that performs the connection switching. 5. The information of the other connectable access point includes a radio field intensity received from the other connectable access point, and the terminal connection control unit determines that the other access point having the highest radio field intensity 4. The wireless LAN system according to claim 3, wherein a terminal that can be connected to the terminal is determined as a terminal that performs the connection switching. 6. The information of the other connectable access point includes transmission path distortion for the other connectable access point, and the terminal connection control unit determines that the other access point has the minimum transmission path distortion. 4. The wireless LAN system according to claim 3, wherein a terminal that can be connected to the terminal is determined as a terminal that performs the connection switching. 7. The terminal connection control unit further includes a second threshold value setting unit that sets a second threshold value that is a lower limit number of connectable terminals, and the connection terminal stored in the first storage unit. Comparing the number with the second threshold set in the second threshold setting unit, if it is determined that the number of connected terminals is less than the second threshold, for all connected terminals, other A connection switching instruction to an access point is issued, and after the connection switching of all the terminals is completed, a power saving mode is set in which only necessary minimum functions of the access point are activated. The wireless LAN system according to any one of claims 1 to 6. 8. The terminal in the wireless LAN system according to claim 1, wherein the terminal is a wireless transmission / reception unit for performing wireless communication with the access point; and the wireless transmission / reception unit. And a terminal control unit that controls access to the wired network via the access point and the access point, and controls connection switching to another access point according to an instruction from the access point. Terminal.