CN102833720B - Roaming system and method for selecting access point by wireless access control device - Google Patents

Abstract

A roaming system and method for selecting access point by wireless access control device, through detecting the access point of the mobile device and transmitting the signal intensity between the access point and the mobile device to the wireless access control device, the wireless access control device informs the mobile device of the technical means of selecting the on-line access point according to the signal intensity between the mobile device and each access point, can give consideration to the network on-line quality and the data transmission efficiency of the mobile device, and achieve the technical effect of high-speed roaming.

Description

Roaming system and method for selecting access point by wireless access control device

technical field

A roaming system and its method, in particular a roaming system and its method in which an access point is selected by a wireless access control device.

Background technique

Roaming (roaming) refers to a behavior that occurs when a mobile device (station, STA) is switched from a wireless signal coverage of a first access point (AccessPoint, AP) to a wireless signal coverage of a second access point.

In the current roaming technology, mainly using WiFi technology, different access points can monitor each other's characteristics on the same channel and within a certain distance, so that the access point can detect that the mobile device has moved to two The intersection area of the wireless signal coverage of two access points. Among them, the method of judging that the mobile device has moved to the intersection of the wireless signal coverage of two access points is usually determined by the mobile device itself, so the mobile device must perform a certain degree of packet collection, so that the mobile device can be in the While confirming the connection status, select the access point with the best connection quality.

Therefore, if it is to be determined on the mobile device whether the mobile device has moved to the intersection of the wireless signal coverage of two access points, the mobile device must sacrifice part of the bandwidth (bandwith) to collect Communication packets, which will reduce the data transmission efficiency of mobile devices.

To sum up, it can be seen that there has long been a problem in the prior art that mobile devices cannot balance network connection quality and data transmission efficiency. Therefore, it is necessary to propose improved technical means to solve this problem.

Contents of the invention

In view of the problem in the prior art that mobile devices cannot take into account both network connection quality and data transmission efficiency, the present invention provides a roaming system and method for selecting an access point by a wireless access control device, wherein:

The roaming system provided by the present invention, in which a wireless access control device selects an access point, at least includes: a mobile device (station, STA); a first access point (AccessPoint, AP), which provides a mobile device connection for forwarding ( forward) the first target device registration (TargetStationRegister) message sent by the mobile device, wherein the first target device registration message sent by the mobile device includes the security key and the four-hand handover identification code of the mobile device; the second access point , used to obtain the MAC address of the mobile device according to the packet transmitted between the mobile device and the first access point after the mobile device is detected, and transmit a target device query (TargetStationQuery) message including the MAC address of the mobile device, and Judging that the roaming identification data in the response message is the same as the roaming identification data corresponding to the MAC address of the mobile device, confirming the identity of the mobile device and then transmitting the detected signal strength with the mobile device; Wireless Access Controller (WAC) After receiving the target device query message sent by the second access point, the first access point sends a monitor access point registration (MonitorAPRegister) message to the mobile device, so that the mobile device The entry point registration message establishes a connection with the second access point. After receiving the target device query message, the wireless access control device searches for the roaming identification data of the mobile device according to the MAC address of the mobile device, and then transmits a message containing the roaming identification data of the mobile device. After the response message is sent to the second access point and used to determine that the signal strength conforms to the predefined roaming rule, the roaming command is sent to the mobile device, so that the mobile device roams to the second access point according to the roaming command.

The roaming method for selecting an access point by a wireless access control device provided by the present invention, the steps at least include: connecting the mobile device to the first access point; sending the first target device registration message to the mobile device through the first access point The wireless access control device, wherein the first target device registration message sent by the mobile device includes the security key of the mobile device and the four-hand handshake identification code; after the second access point detects the mobile device, according to the mobile device and The MAC address of the mobile device is obtained from the packet transmitted between the first access points, and a target device query message containing the MAC address of the mobile device is sent to the wireless access control device, so that the wireless access control device transmits the message through the first access point The monitoring access point registration message is sent to the mobile device; the mobile device will establish a connection with the second access point according to the received monitoring access point registration message; address, searching for the roaming identification data of the mobile device, and then sending a response message containing the roaming identification data of the mobile device to the second access point; the second access point judges that the roaming identification data in the response message corresponds to the MAC address of the mobile device Confirm the identity of the mobile device when the roaming identification data is the same; the second access point transmits the detected signal strength between the mobile device and the second access point to the wireless access control device; the wireless access control device judges that the signal strength meets the preset After the roaming rules are defined, a roaming command is sent to the mobile device; the mobile device roams to the second access point according to the roaming command.

The system and method provided by the present invention are as above, and the difference between the present invention and the prior art is that the present invention detects the signal strength between the access point of the mobile device and the mobile device to the wireless access control device, and the wireless access control The device notifies the mobile device to select an access point for connection according to whether the signal strength between the mobile device and each access point conforms to the pre-defined roaming rules, so as to solve the problems existing in the prior art and achieve the technical effect of high-speed roaming.

Description of drawings

FIG. 1A and FIG. 1B are schematic diagrams of roaming proposed by the present invention.

FIG. 2A is a flowchart of a roaming method for selecting an access point by a wireless access control device according to the present invention.

FIG. 2B is a flowchart of an additional method for the first access point to transmit the first signal strength according to the present invention.

FIG. 2C is a flow chart of an additional method for the second access point to transmit the second signal strength according to the present invention.

FIG. 2D is a detailed flow chart of the method for the first access point to transmit the first signal strength according to the present invention.

FIG. 2E is an additional flow chart of the roaming method for selecting an access point by a wireless access control device according to the present invention.

[Description of main component symbols]

100 mobile devices

201 first access point

202 second access point

300 wireless access control device

401 first signal coverage

402 The second signal covers a range.

detailed description

The features and implementation methods of the present invention will be described in detail below in conjunction with the drawings and embodiments, the content is enough to enable anyone familiar with the relevant art to easily and fully understand the technical means used to solve the technical problems of the present invention and implement them accordingly, thereby realizing The effect that the present invention can achieve.

In the present invention, a wireless access control device (WirelessAccessController, WAC) connected to an access point (AccessPoint, AP) determines that there is a connection quality around the mobile device (station, STA) that is higher than that of the first access point currently connected. When the second access point is better, the mobile device is notified of roaming from the first access point to the second access point.

In the present invention, the access point connected to the mobile device 100 before roaming is called "first access point", and the access point connected to mobile device 100 after roaming is called "second access point". In addition, in the present invention, all access points in the wireless network where the mobile device is located will also be represented by access points, and other access points that are not currently connected to the mobile device will be represented by "other access points". point.

The operation of the system of the present invention will be described below with "FIG. 1A" and "FIG. 1B". As shown in FIG. 1A or FIG. 1B , the system of the present invention includes a mobile device 100 , a first access point 201 , a second access point 202 and a wireless access control device 300 .

The mobile device 100 can move arbitrarily. When the mobile device 100 enters a wireless network, the mobile device 100 will detect the presence of surrounding access points, and use a four-way handshake (4-wayhandshake) to connect with one of the detected access points. At this time, the access point connected with the mobile device 100 is the "first access point". The mobile device 100 is also responsible for continuously detecting the signal strength (ReceiveSignalStrengthIndicator, RSSI) of other access points after connecting with the access point.

In addition, the mobile device 100 may also establish a connection with the AP indicated in the monitor AP register message after receiving the monitor AP register (MonitorAP Register) message transmitted by the wireless access control apparatus 300 .

Regardless of whether the mobile device 100 is connected to the access point in a four-handed handshake, or is connected to the access point according to the monitoring access point registration message sent by the wireless access control device 300, before the mobile device 100 is connected to the access point , will send communication packets to transmit data before connecting. In some embodiments, the fourth MAC network address in the communication packet can be used as roaming identification data (roamdomain) of the mobile device 100, but the roaming identification data mentioned in the present invention is not limited thereto.

After the mobile device 100 is connected to the first access point 201 , it can send a first target device registration (TargetStationRegister) message to the wireless network control apparatus 300 through the first access point 201 . Wherein, the first target device registration message transmitted by the mobile device 100 may include the security key (SecurityKey) of the mobile device 100 and the four-hand handshake identification code, but the first target device registration message described in the present invention does not take this as a limit.

Similarly, after the mobile device 100 is connected to the second access point 202 , it can send the second target device registration message to the wireless access control apparatus 300 through the second access point 202 . Wherein, the second target device registration message transmitted by the mobile device 100 may include the security key and the roaming identification code of the mobile device 100, but the second target device registration message in the present invention is not limited thereto.

The mobile device 100 is also responsible for receiving a roaming command (roaming command) transmitted from the wireless access control apparatus 300 through the first AP 201 or the second AP 202, and roaming to the second AP 202 in the roaming command.

The first access point 201 has a first signal coverage area 401, provides multiple mobile devices in the first signal coverage area 401 online, and is responsible for forwarding (forward) the first target device registration message transmitted by the mobile device 100 to the wireless network. Access control device 300. After receiving the first target device registration message, the first access point may store the security key in the first target device registration message.

The first access point 201 is also responsible for monitoring (sniffer) whether the mobile device 100 communicates with other access points after connecting with the mobile device 100. If the first access point 201 detects that the mobile device 100 is communicating with other access points After transmitting the communication packet, it is further judged whether the roaming identification data in the monitored communication packet is the same as the roaming identification data of the mobile device. If the roaming identification data in the communication packet is the same as the roaming identification data of the mobile device, the first access The point 201 obtains the signal strength between the first access point 201 and the mobile device, and transmits the obtained signal strength to the wireless access control device 300 . In the present invention, the signal strength transmitted by the first access point 201 is called "first signal strength".

In fact, the first access point 201 will transmit the signal strength between each mobile device connected to the first access point 201 at a specific frequency (that is, a specific time interval), that is, the first access point 201 The first access point 201 will transmit the signal strength between the mobile device 100 and the mobile device 100 to the wireless access control device 300 after listening to the communication packets transmitted by the mobile device 100 and other access points within a specific time (time interval). In a certain time interval, if the first access point 201 does not hear the communication packet between the mobile device 100 and other access points, the first access point 201 will not transmit the signal strength with the mobile device 100 .

In addition, the first access point 201 may also forward the received monitoring access point registration message to the mobile device 100 after receiving the monitoring access point registration message sent by the wireless access control device 300 .

The second access point 202 has a second signal coverage area 402, and is responsible for trying to monitor the connection packets transmitted between the mobile device 100 and the first access point 201 after the mobile device 100 moves into the second signal coverage area 402, for example, The KeepAlive packet sent from the mobile device 100 to the first access point or the ACK packet sent back to the mobile device 100 by the first access point.

The second access point 202 can obtain the MAC address of the mobile device 100 from the connection packet after listening to the connection packet transmitted between the mobile device 100 and the first access point 201, and send a target device query containing the MAC address of the mobile device 100 (TargetStationQuery) message to the wireless access control device 300 .

After the wireless access control device 300 sends back the response message of the target device query message, the second access point 202 can obtain the roaming identification data corresponding to the MAC address of the mobile device 100 from the response message of the target device query message, and determine Whether the roaming identification data in the response message and the roaming identification data of the mobile device 100 are the same, so as to confirm the identity of the mobile device 100 when the roaming identification data in the response message and the roaming identification data of the mobile device 100 are the same.

After confirming the identity of the mobile device 100 , the second access point 202 may transmit the signal strength with the mobile device 100 to the wireless access control apparatus 300 . In the present invention, the signal strength transmitted from the second access point 202 to the wireless access control device 300 is called "second signal strength".

Similar to the first access point 201, the second access point 202 can listen to the second communication packet transmitted between the mobile device 100 and other access points within a specific time interval, and transmit the second signal strength to the wireless network. Access control device 300.

Generally speaking, the first access point 201 can write the signal strength between each mobile device connected to the first access point 201 into the signal strength report data, and transmit the signal strength report data to the wireless access point at a specific frequency. The control device 300, the second access point 202 can also use the method of the first access point 201 to transmit the first signal strength, write the second signal strength into the signal strength report data, and then send the signal strength report data to the wireless access point. However, the manner in which the first access point 201 transmits the first signal strength to the wireless access control device 300 or the second access point 202 transmits the second signal strength is not limited to the above.

It is worth mentioning that the first access point 201 and the second access point 202 only provide different functions to the mobile device 100, and there is no difference between the two in practice, that is, the mobile device 100 uses four hands After the mobile device 100 is connected to an access point by means of hand grip, or after the mobile device 100 roams from the access point to another access point, for the mobile device 100, the access point is the first access point described in the present invention. An access point, and if another mobile device roams from other access points to the same access point, then for the roaming mobile device, the access point is the "second access point" described in the present invention ".

The wireless access control device 300 is responsible for receiving the first target device registration message sent by the mobile device 100 through the first access point 201, and the first signal strength between the mobile device 100 and the mobile device 100 sent by the first access point 201 , the second target device registration message sent by the mobile device through the second access point 202, the target device query message sent by the second access point 202, and the communication with the mobile device sent by the second access point 202 Second signal strength between 100.

The wireless access control device 300 is responsible for sending a response message to the second access point 202 after receiving the target device query message sent by the second access point 202, and sending a monitoring access point registration message through the first access point 201. message to mobile device 100.

The wireless access control apparatus 300 is also responsible for judging whether the second signal strength between the second access point 202 and the mobile device 100 complies with the predefined roaming rules. If the second signal strength complies with the predefined roaming rules, it means that the mobile device 100 In general, the most suitable access point for online connection is the second access point 202. Therefore, the wireless access control device 300 can transmit a roaming command to the mobile device 100, so that the mobile device 100 can roam from the first access point 201 according to the roaming command. to the second access point 202 .

The predefined roaming rules described in the present invention vary with different antennas used by the access point. In some embodiments, when the antenna used by the access point is a leak cable (LeakCable), the roaming rule can be Whether the second access point 202 transmits the second signal strength between the second access point 202 and the mobile device 100 to the wireless access control device 300 for the first time, if so, the second signal strength complies with the roaming rule; in some embodiments , when the antenna used by the access point is a directional antenna (directional antenna), the roaming rule may be that the second signal strength is greater than a predetermined strength threshold; and in some embodiments, the antenna used by the access point is omnidirectional When using an omniantenna, the roaming rule may be that the second signal strength is greater than the first signal strength.

In practice, when the antenna used by the access point is a directional antenna or an omnidirectional antenna, the pre-defined roaming rules can usually include Whether the duration that the second signal strength is greater than the first signal strength or the strength threshold exceeds a predetermined time threshold, that is, the wireless access control device 300 determines that the second signal strength is greater than the first signal strength or the strength threshold Finally, it is also necessary to judge whether the second signal strength is greater than the first signal strength or the duration of the strength threshold exceeds the predetermined time threshold, if the second signal strength is greater than the first signal strength or the duration of the strength threshold also exceeds the threshold , the wireless access control apparatus 300 will determine that the second signal strength complies with the predefined roaming rule, and transmit the roaming command to the mobile device 100 .

The wireless access control device 300 is also responsible for deleting the previously stored connection status data of the mobile device 100 after receiving the second target device registration message sent by the mobile device 100, and recording that the mobile device has connected to the second access point 202 .

Next, an embodiment is used to illustrate the operating system and method of the present invention, and please refer to "FIG. 2A" for the main flow chart of the roaming method for selecting an access point by a wireless access control device according to the present invention. In this embodiment, it is assumed that the mobile device 100 is a notebook computer, but the mobile device 100 of the present invention is not limited thereto, and any other device that can use the communication protocol of IEEE802.11 can be referred to as the present invention. The mobile devices mentioned above, for example, mobile phones, PDAs, etc.

If the wireless network architecture in this embodiment is as shown in "FIG. 1A", the mobile device 100 enters the first signal coverage area 401 owned by the first access point 201 (step 501), but does not enter the second access point. After 202 possessing the second signal coverage 402, the mobile device 100 can connect to the first access point 201 (step 540). At this point, the mobile device 100 is connected to the first access point 201 in a four-handed handshake.

After the mobile device 100 is connected to the first access point 201 (step 540), the mobile device 100 can send the first target device registration message to the first access point 201, so as to forward the first target device through the first access point 201. Register a message to the wireless access control device 300 (step 550).

After the mobile device 100 transmits the first target device registration message to the wireless access control device 300 through the first access point 201 (step 550), the first access point 201 can continuously detect the mobile device 100 and the first signal strength between the first APs 201, and transmit the detected first signal strength to the wireless access control device 300 (step 580). Wherein, the time interval for the first access point 201 to detect the first signal strength is, for example, 50 ms, 100 ms, etc., but the present invention is not limited thereto.

In order to reduce the load of the wireless access control device 300, before the first access point 201 transmits the first signal strength to the wireless access control device 300, as shown in the flow of "Fig. The second access point 202 transmits the communication packet (step 561). If the first access point 201 does not hear the communication packet between the mobile device 100 and the second access point 202, it means that the mobile device 100 has not moved into the second signal coverage area 402 owned by the second access point 202. At this time, only the first access point 201 of the mobile device 100 can be connected, so no roaming is required. Therefore, the wireless access control apparatus 300 does not need to process the signal strength between the mobile device 100 and each access point, so the first access point 201 may not transmit the detected first signal strength.

And if the mobile device 100 has moved to the intersection of the first signal coverage area 401 owned by the first access point 201 and the second signal coverage area 402 owned by the second access point 202 (step 601), as shown in "Fig. 1B", the mobile device 100 will detect the existence of the second access point 202 because it is constantly detecting other access points, and then the mobile device 100 will communicate with the second access point 202 Communication packets are generated for the exchange of data. In this way, the first access point 201 monitoring the packets sent by the mobile device 100 can monitor the communication packets transmitted between the mobile device 100 and the second access point 202 .

After the first access point 201 monitors the communication packet transmitted between the mobile device 100 and the second access point 202, the first access point 201 can further determine whether the roaming identification data recorded in the monitored communication packet is Same as the roaming identification data of the mobile device 100 (step 563). Since the communication packet monitored by the first access point 201 is a data exchange packet between the mobile device 100 and the second access point 202, the first access point 201 can determine that the roaming identification data in the communication packet is related to the mobile device. The roaming identification data of the device 100 are the same.

Then, the first access point 201 can detect the first signal strength between the first access point 201 and the mobile device 100, and transmit the detected first signal strength to the wireless access control device 300 (step 580) . In this embodiment, it is assumed that the first access point 201 will write the first signal strength between the first access point 201 and the mobile device 100 into the signal strength report data, and then write the signal strength recorded with the first signal strength The report data is sent to the wireless access control device 300, but the manner in which the first access point 201 sends the first signal strength is not limited thereto.

In addition, in practice, the first access point 201 will continuously transmit the first signal strength between the first access point 201 and the mobile device 100 to the wireless access control apparatus 300 at a certain time interval. Wherein, the time interval for the first access point 201 to transmit the first signal strength to the wireless access control device 300 is, for example, 50 ms, 100 ms, etc., but the time interval described in the present invention is not limited thereto.

After the mobile device 100 moves to the intersection of the first signal coverage area 401 owned by the first access point 201 and the second signal coverage area 402 owned by the second access point 202 (step 601), the second access point The access point 202 can detect the presence of the mobile device 100 when there is a packet transfer between the mobile device 100 and the first access point 201, and then the second access point 202 can detect the presence of the mobile device 100 according to the communication between the mobile device 100 and the first access point 201. The MAC location of the mobile device 100 is obtained from the packet transmitted between the points 201, and a target device query message including the MAC address of the mobile device 100 is sent to the wireless access control device 300 (step 620).

After receiving the target device query message transmitted by the second access point 202, the wireless access control apparatus 300 may transmit a monitoring access point registration message to the first access point 201, and the first access point 201 receives the wireless After accessing the monitoring access point registration message sent by the control device 300, the received monitoring access point registration message is forwarded to the mobile device 100 (step 630).

After the mobile device 100 receives the monitoring access point registration message forwarded by the wireless access control device 300 through the first access point 201 (step 630), the mobile device 100 will follow the received monitoring access point registration message and The second access point 202 establishes a connection (step 640).

Similarly, after the wireless access control device 300 receives the target device query message, the wireless access control device 300 can search for the roaming identification data of the mobile device 100 according to the MAC address of the mobile device 100, and then transmit the roaming identification data containing the mobile device 100. The data response message is sent to the second access point 202, so that the second access point 202 can confirm the identity of the mobile device 100 through the roaming identification data in the received response message.

After the second access point 202 confirms the identity of the mobile device 100, the second access point 202 can continuously detect the second signal strength between the mobile device 100 and the second access point 202 at a certain time interval, and send The detected second signal strength is sent to the wireless access control device 300 (step 680). Wherein, the time interval for the second access point 202 to detect the second signal strength is, for example, 50 ms, 100 ms, etc., but the present invention is not limited thereto.

However, similarly, in order to reduce the load on the wireless access control device 300, before the second access point 202 transmits the second signal strength to the wireless access control device 300, it can first monitor Whether the mobile device 100 communicates the connection packet with the first access point 201 (step 662).

Due to the characteristics of WiFi, when the mobile device 100 moves to the intersection of the first signal coverage area 401 owned by the first access point 201 and the second signal coverage area 402 owned by the second access point 202, the second access point The access point 202 will be able to monitor the connection packet transmitted between the mobile device 100 and the first access point 201, therefore, the second access point 202 can judge whether the roaming identification data recorded in the monitored connection packet is consistent with The roaming identification data of the mobile device 100 is the same (step 663). Since the connection packet monitored by the second access point 202 is a packet for the mobile device 100 and the first access point 201 to confirm that the connection is maintained, the second access point 202 can determine that the roaming identification data in the connection packet is consistent with The roaming identification data of the mobile device 100 is the same.

Then, the second access point 202 can detect the second signal strength between the second access point 202 and the mobile device 100, and transmit the detected second signal strength to the wireless access control device 300 (step 680) . Wherein, the second access point 202 can write the second signal strength between the second access point 202 and the mobile device 100 into In the signal strength report data (step 681), the signal strength report data recorded with the second signal strength is transmitted to the wireless access control device 300 (step 685), but the second access point 202 transmits the second signal strength It is not limited to this.

In addition, the second access point 202 will continuously transmit the second signal strength between the second access point 202 and the mobile device 100 to the wireless network at the same time interval as the first access point 201 (that is, at the same frequency). Access control device 300.

The first access point 201 continuously transmits the detected first signal strength to the wireless access control device 300 (step 580), and the second access point 202 continuously transmits the detected second signal strength to the wireless access control device 300. After accessing the control device 300 (step 680), the wireless access control device 300 can determine whether the second signal strength meets the predefined roaming rules (step 710), so as to select the best access point for the mobile device 100 . Wherein, the time interval for the wireless access control device 300 to judge whether the second signal strength complies with the predefined roaming rules is usually the same as the first access point 201/second access point 202 transmitting the first signal strength/second signal strength. The time intervals are the same, but the present invention is not limited thereto, wherein the predefined roaming rules are related to the deployed antenna system.

In this embodiment, when the antenna used by the mobile device 100 and the access point is a leaky cable, the roaming rule can be defined as whether the second access point 202 transmits the data between the second access point 202 and the mobile device 100 for the first time The second signal strength is sent to the wireless access control device 300. At this time, if the wireless access control device 300 judges that the second signal between the second access point 202 and the mobile device 100 transmitted by the second access point 202 is received for the first time strength, the wireless access control device 300 will determine that the second signal strength complies with roaming rules, and if the second access point 202 has previously sent the second signal strength to the wireless access control device 300, the wireless access control device 300 will It is determined that the second signal strength does not comply with the roaming rule.

If the antennas used by the mobile device 100 and the access point are directional antennas, the roaming rule in this embodiment can be defined as the second signal strength is greater than the predetermined strength threshold, that is, if the wireless access control device 300 determines that After the second signal strength transmitted by the second access point 202 is greater than the predetermined strength threshold, the wireless access control device 300 determines that the second signal strength complies with the roaming rule. In addition, the roaming rule may also include that the duration of the second signal strength greater than the predetermined strength threshold exceeds the predetermined time threshold. In this case, the wireless access control device 300 determines that the second After the second signal strength is greater than the predetermined strength threshold, it is also necessary to determine that the duration of the second signal strength greater than the predetermined strength threshold also exceeds the predetermined time threshold, so that the wireless access control device 300 will determine that the second signal strength meets the roaming rules.

However, when the first antenna used by the mobile device 100 and the access point is an omnidirectional antenna, the roaming rule in this embodiment can be defined as the second signal strength being greater than the first signal strength, or even similar to the definition for a directional antenna. , the roaming rule may further include that the duration in which the second signal strength is greater than the first signal strength exceeds a predetermined time threshold. In this way, in addition to determining that the second signal strength transmitted by the second access point 202 is greater than the first signal strength transmitted by the first access point 201, the wireless access control device 300 also needs to determine that the second signal strength is greater than The duration of the first signal strength also exceeds the predetermined time threshold, so that the wireless access control device 300 judges that the second signal strength complies with the roaming rule, otherwise the wireless access control device 300 will not consider that the second access point 202 is relatively The first access point 201 is more suitable for the mobile device 100 to connect to.

After the wireless access control device 300 judges that the second signal strength conforms to the predefined roaming rules, the wireless access control device 300 will send a roaming command to the mobile device through the first access point 201 and/or the second access point 202 100 (step 720).

After the wireless access control apparatus 300 transmits the roaming command to the mobile device 100 through the access point (step 720), the mobile device 100 can roam from the first access point 201 to the second mobile device according to the roaming command transmitted by the wireless access control device 300. Two access points 202 (step 730).

Then please continue to refer to "Fig. 2E", after the mobile device 100 roams to the second access point 202, the mobile device 100 can send the second target device registration message to the wireless access control device 300 through the second access point 202 (step 750).

After the wireless access control device 300 receives the second target device registration message sent by the mobile device 100, the wireless access control device 300 may delete the online status data of the mobile device (step 792), and record that the mobile device has been connected to the second target device. Two access points 202 (step 796), thus completing all roaming procedures.

In the above embodiment, when the second access point 202 does not hear the connection packet between the mobile device 100 and the first access point 201, it means that the mobile device 100 has moved to the first signal possessed by the first access point 201 Outside the coverage area 401 , only the second access point 202 of the mobile device 100 can be connected at this time, so roaming is not required. Therefore, the wireless access control apparatus 300 does not need to process the signal strength between the mobile device 100 and each access point, so the second access point 202 may not transmit the detected first signal strength.

In summary, it can be seen that the difference between the present invention and the prior art lies in that the access point that detects the mobile device transmits the signal strength between the mobile device and the wireless access control device, and the wireless access control device bases the mobile device Whether the signal strength between the device and each access point complies with the pre-defined roaming rules is a technical means to inform the mobile device to select the access point for connection. This technical means can solve the problem that the mobile device in the existing technology cannot take into account the quality of the network connection. Problems with data transmission efficiency, and then achieve the technical effect of high-speed roaming.

Furthermore, the roaming method for selecting an access point by a wireless access control device of the present invention can be implemented in hardware, software, or a combination of hardware and software, and can also be implemented in a centralized manner in a computer system or distributed in different components. Distributed implementation of several interconnected computer systems.

Although the embodiments provided by the present invention are as above, the content described is not intended to directly limit the patent protection scope of the present invention. Anyone with ordinary knowledge in the technical field of the present invention, without departing from the spirit and scope provided by the present invention, makes some changes and modifications to the form and details of the implementation of the present invention, all of which belong to the patent protection of the present invention scope. The scope of patent protection of the present invention must still be defined by the appended claims as the criterion.

Claims (10)

1. A roaming method for selecting an access point by a wireless access control device, the roaming method at least includes the following steps: a mobile device is connected to a first access point; The mobile device transmits a first target device registration message to a wireless access control device through the first access point, wherein the first target device registration message transmitted by the mobile device includes a security key of the mobile device and Four-handed handshake identification code; After a second access point detects the mobile device, it obtains the MAC address of the mobile device from the packet transmitted between the mobile device and the first access point, and transmits a message containing the MAC address of the mobile device. The target device sends a query message to the wireless access control device, so that the wireless access control device transmits a monitoring access point registration message to the mobile device through the first access point; The mobile device will establish a connection with the second access point according to the received monitoring access point registration message; After receiving the target device query message, the wireless access control device searches for the roaming identification data of the mobile device according to the MAC address of the mobile device, and then sends a response message including the roaming identification data of the mobile device to the second Access Point; confirming the identity of the mobile device when the second access point determines that the roaming identification data in the response message is the same as the roaming identification data corresponding to the MAC address of the mobile device; The second access point transmits a detected signal strength between the mobile device and the second access point to the wireless access control device; After the wireless access control device judges that the signal strength complies with a predefined roaming rule, it sends a roaming command to the mobile device; and The mobile device roams to the second access point according to the roaming command. 2. The roaming method for selecting an access point by the wireless access control device as claimed in claim 1, wherein the roaming method starts with the mobile device sending the first target device registration message to the wireless access point through the first access point After the step of entering the control device, it further includes the first access point listening to a communication packet transmitted between the mobile device and the second access point, and judging the roaming identification data in the communication packet and the roaming identification data of the mobile device After being identical, transmitting the signal strength between the mobile device and the first access point to the wireless access control device at a certain frequency. 3. The roaming method for selecting an access point by a wireless access control device as claimed in claim 1, wherein the roaming method further includes the second step after the second access point detects the mobile device. The access point detects that the mobile device transmits a connection packet with the first access point, and after judging that the roaming identification data in the connection packet is the same as the roaming identification data of the mobile device, it continues to transmit the signal strength to the wireless access point. into the control unit. 4. The roaming method for selecting an access point by a wireless access control device as claimed in claim 1, wherein the second access point transmits the signal strength between the mobile device and the second access point to the wireless access point The step of accessing the control device is that the second access point writes the signal strength into a signal strength report data, and transmits the signal strength report data to the wireless access control device at a specific frequency. 5. The roaming method for selecting an access point by the wireless access control device according to claim 1, wherein the roaming method further includes the mobile device after the mobile device roams to the second access point according to the roaming command Sending a second target device registration message to the wireless access control device through the second access point, the wireless access control device deletes the online state data of the mobile device after receiving the second target device registration message, And record the step that the mobile device has been connected to the second access point. 6. A roaming system in which an access point is selected by a wireless access control device, the roaming system at least includes: a mobile device; A first access point, providing the mobile device with a connection to forward a first target device registration message sent by the mobile device, wherein the first target device registration message sent by the mobile device includes the mobile device's Security key and four-hand handshake identification code; A second access point, after detecting the mobile device, obtains the MAC address of the mobile device according to the packet transmitted between the mobile device and the first access point, and transmits the MAC address including the mobile device Address a target device query message, and determine that the roaming identification data in a response message is the same as the roaming identification data corresponding to the MAC address of the mobile device, and confirm the identity of the mobile device to transmit the detected mobile device. a signal strength between devices; and A wireless access control device, configured to transmit a monitoring access point registration message to the mobile device through the first access point after receiving the target device query message sent by the second access point, so that the The mobile device establishes a connection with the second access point according to the received monitoring access point registration message, and the wireless access control device searches for the mobile device according to the MAC address of the mobile device after receiving the target device query message roaming identification data of the mobile device, and then transmit the response message including the roaming identification data of the mobile device to the second access point and use it to judge that the signal strength conforms to a predefined roaming rule, and then send a roaming command to the mobile device , enabling the mobile device to roam to the second access point according to the roaming command. 7. The roaming system for selecting an access point by a wireless access control device as claimed in claim 6, wherein the predefined roaming rule is that the signal strength is greater than the signal strength transmitted by the first access point and the signal strength The duration longer than the signal strength transmitted by the first access point satisfies a predetermined time threshold, the signal strength is the signal strength between the second access point and the mobile device for the first time transmission, or the signal strength is greater than a predetermined strength threshold value. 8. The roaming system for selecting an access point by a wireless access control device as claimed in claim 6, wherein the first access point is further used to detect that the mobile device transmits a communication packet with the second access point , and after judging that the roaming identification data in the communication packet is the same as the roaming identification data of the mobile device, transmitting the signal strength between the mobile device and the first access point to the wireless access control device at a certain frequency. 9. The roaming system for selecting an access point by a wireless access control device as claimed in claim 6, wherein the second access point is further used to detect that the mobile device transmits a connection packet with the first access point , and after judging that the roaming identification data in the connection packet is the same as the roaming identification data of the mobile device, continue to transmit the signal strength to the wireless access control device. 10. The roaming system in which an access point is selected by a wireless access control device as claimed in claim 6, wherein the mobile device is further configured to forward a message through the second access point after roaming to the second access point. The second target device registration message is sent to the wireless access control device, and the wireless access control device is further configured to delete the online state data of the mobile device after receiving the second target device registration message, and record that the mobile device has Connect to the second access point.