CN1735051A - Wireless switching device and its method - Google Patents

Abstract

The invention discloses a wireless switching device, which is used for a wireless local area network user terminal to switch between different access points, including at least two wireless network cards, and each wireless network card searches for access points that can be accessed; and through After the searched access point is connected to the wireless local area network, the wireless data packet is sent and received between the access point; and the data exchange unit is respectively connected with each wireless network card and the user terminal, and is used to receive the wireless network card. The data packets sent by the user terminal are forwarded to the user terminal; and the data packets sent by the user terminal are forwarded to the wireless network card. Correspondingly, the invention also discloses a wireless switching method. The present invention can shorten the time for the user terminal to search for a new access point during the switching process, so that the user terminal can quickly complete the switching process.

Description

Wireless switching device and method thereof

technical field

The present invention relates to the technical field of wireless local area network, in particular to a wireless switching device and method applied in a wireless local area network system.

Background technique

Wireless Local Area Network (WLAN, Wireless Local-Area Network) is a network system that follows the 802.11 protocol of the Institute of Electrical and Electronics Engineers (IEEE, Institute of Electrical and Electronics Engineers) and uses electromagnetic waves as the transmission medium.

The IEEE 802.11 protocol includes two physical layer standards: the 802.11a standard and the 802.11b standard. The working frequency band of the 802.11a standard is at 2.4G, while the working frequency band of the 802.11b standard is at 5G; both the 802.11a standard and the 802.11b standard use the same Media Access Control Protocol (MAC, Media Access Control) technology.

The wireless local area network system is mainly composed of an access point (AP, Access Point) and a terminal inserted with a wireless network card; the following two working modes can be established between different terminals:

A. Peer-to-peer (Ad-Hoc) mode without access point AP: In this mode, terminals can only communicate directly through point-to-point mode;

B. Infrastructure mode with access point AP forwarding: In this mode, the terminal can communicate with the wired network system through the access point AP; as shown in Figure 1, it is the structure of the wireless LAN system using the infrastructure mode In the topology diagram, a terminal 1 inserted with a wireless network card can access a wired network system through an access point AP2.

Wherein, the access point AP is equivalent to a hub (Hub) in the wireless local area network system, and can implement data exchanged between users to be forwarded between multiple interfaces, wherein the interfaces include wireless interfaces and wired interfaces.

At present, in the wireless local area network system, the user usually finds a new access point AP in two ways, as follows:

(1) APs of different access points will periodically broadcast and send beacon messages, so that users can understand their current status information through the periodic broadcast of beacon messages;

According to the current state information of different access points AP, the user selects the corresponding access point AP to access the wireless local area network.

(2) The user actively sends active detection frames to different access points AP;

After the access point AP receives the active detection frame, it will feed back its own corresponding status information to the user, and the user determines to select the corresponding access point AP to access the wireless local area network according to the feedback information of each access point AP.

After the user selects the corresponding access point AP, the main process of communicating with the access point AP is as follows:

The user terminal sends an association request (association request) frame to the access point AP, so as to request the access point AP to join the wireless local area network system;

After receiving the association request frame, the access point AP feeds back an association response (association response) frame to the user terminal to show that the user agrees to join the wireless local area network system.

However, in a wireless local area network system, when a user terminal moves from the area covered by the current access point AP to the area covered by other access points AP, the user terminal needs to re-search for a new access point AP, and search for a new access point AP. The access point AP starts a new communication connection process.

Please refer to Fig. 2, which is a simple schematic diagram of handover processing of a user terminal in a wireless local area network system; because in a wireless local area network system, a user terminal can only communicate with one access point AP at the same time, so when a user terminal switches from When the coverage area of the current access point AP1 moves to the coverage area of the next access point AP2, it is necessary to perform switching processing between the previous access point AP1 and the next access point AP2, that is, the user terminal In this process, it is necessary to disconnect the communication connection with the previous access point AP1, scan or search for other accessible access points AP2, and re-establish the communication connection with the new access point AP2 after searching.

However, at present, when the user terminal is moving, the search time for scanning and searching for other access points APs that can be accessed is generally as long as several seconds. The long search time is usually unbearable on the user side, because the user terminal may have to start the next handover process before the current handover process is completed during the high-speed mobile process. It can be seen that the prior art The handover processing method will undoubtedly affect the communication quality of the user terminal.

Contents of the invention

The technical problem to be solved by the present invention is to propose a wireless switching device and its method, so as to shorten the time for a user terminal to search for a new access point during the switching process, so that the user terminal can quickly complete the switching process.

In order to solve the above problems, the present invention proposes a wireless switching device, which is used for switching between different access points for a wireless local area network user terminal, including:

At least two wireless network cards, each wireless network card searches for an access point that can be accessed; and after accessing the wireless local area network through the searched access point, transmits and receives wireless data packets with the access point; and

The data exchange unit is connected with each wireless network card and the user terminal respectively, and is used for forwarding the data packet received by the wireless network card to the user terminal; and forwarding the data packet sent by the user terminal to the wireless network card.

The device also includes a data packet selection unit, each wireless network card is connected to the data exchange unit through the data packet selection unit, and is used to select one of the data packets with the same data content forwarded by each wireless network card. The data packet is sent to the data exchange unit for processing.

Wherein the wireless network card is connected to the data exchange unit through an Ethernet interface. The data exchange unit is connected to the user terminal through an Ethernet interface. The wireless switching device is internally or externally connected to the user terminal.

Correspondingly, the present invention also proposes a wireless handover method for a wireless local area network user terminal to perform handover processing between different access points, including steps:

(1) Redundantly configuring at least one wireless network card for the user terminal;

(2) When the user terminal maintains a communication connection with the original access point, the redundantly configured wireless network card

Search for other access points that can be accessed separately;

(3) The user terminal selects one of the searched access points as a new access point to be accessed;

(4) The user terminal establishes a communication connection with the selected access point, and disconnects from the original access point

communication connection.

Wherein the wireless network card of redundant configuration in the step (2) searches for the corresponding access point by scanning the corresponding access point status information carried in the beacons broadcast by different access points on the public channel; or

Send active detection frames to each access point, and search for the corresponding access point by viewing the status information fed back by each access point.

Wherein in the step (3), the user terminal selects the access point with the highest transmission signal strength among the searched access points as the new access point to be accessed.

Described step (4) also comprises the step:

Before the user terminal disconnects the communication connection with the original access point, the processing method adopted by the user terminal is as follows:

Randomly select one of the data packets carrying the same data content for processing; or

All packets carrying the same data content are discarded.

Wherein the step (4) further includes a step: when the wireless network card currently in working state fails, the user terminal transfers the follow-up work to another wireless network card with redundant configuration to continue.

The wireless switching device and its method of the present invention configure at least two wireless network cards for the terminal access device, so that the user terminal in the existing wireless local area network system is in the process of high-speed movement. When one of the wireless network cards is in the working state, the remaining configurations In this way, when the location of the user terminal is switched, the other wireless network cards that play a redundant role can actively search for a new access point when the user terminal communicates normally with the previous access point. Therefore, in the prior art, when the user terminal frequently undergoes handover processing, the time taken to search for a new access point can be shortened, and the speed and speed at which the user terminal completes the handover process can be improved. The communication quality of the user terminal.

Description of drawings

Fig. 1 is the structural topology diagram of the wireless local area network system adopting the infrastructure mode;

Fig. 2 is a simple schematic diagram of handover processing performed by a user terminal in a wireless local area network system;

3 is a schematic diagram of specific components of the wireless switching device of the present invention and the working principle of the switching device;

Fig. 4 is a specific composition block diagram of the wireless switching device in which the data packet selection unit is added to prevent the wireless switching device of the present invention from receiving multiple duplicate data packets due to the existence of multiple wireless network cards;

Fig. 5 is a flow chart of the realization principle of the wireless handover method of the present invention;

FIG. 6 is a schematic diagram of a user terminal switching between multiple access points after adopting the wireless switching device and method of the present invention.

Detailed ways

The wireless switching device and the method thereof of the present invention adopt the mode of redundantly configuring wireless network cards to improve the speed of searching for new access points AP in the process of frequent switching by high-speed mobile users in the wireless local area network system, so as to improve the speed of frequent switching of user terminals. Communication quality in the process.

The specific implementation of the wireless switching device of the present invention will be described in detail below in conjunction with each accompanying drawing; please refer to Figure 3, which is a schematic diagram of the specific components of the wireless switching device of the present invention and the working principle of the switching device; wherein the wireless switching device The switching device mainly includes at least two wireless network cards 10 and a data exchange unit 20, and the specific functions and connections of each entity are as follows:

At least two wireless network cards 10, each wireless network card 10 is used to search for the access point AP that can be accessed respectively; Sending and receiving processing of data packets; wherein each wireless network card 10 is responsible for scanning common channels in the wireless LAN system, and selecting a suitable wireless LAN access point AP for access processing according to the transmission signal strength of each access point AP. And after the wireless network card 10 is connected to the wireless local area network system by the selected access point AP, it is responsible for the wireless interface (the wireless interface refers to the interface connected wirelessly with the access point AP) and the data interface (referring to the wired connection with the data exchange unit 20). interface, data packet forwarding between data interface 1 and data interface 2) as shown in the figure; and different wireless network cards 10 respectively select different physical channels to communicate with the selected access point AP.

The data exchange unit 20 is connected with each wireless network card 10 and the user terminal respectively, and is used for forwarding the data packet received by the wireless network card 10 to the user terminal; Wherein the data exchange unit 20 is mainly used for data packet forwarding between data interfaces, and its forwarding rules to data packets are as follows:

The data packet transmitted from the data interface (data interface 1 or data interface 2 shown in the figure) connected with the wireless network card 10 is only forwarded to the data interface (data interface 3 shown in the figure) connected with the user terminal; The direction indicated by the dotted arrow is the direction of packet forwarding;

And forward the data packet sent by the data interface (data interface 3 shown in the figure) connected with the user terminal to all data interfaces (data interface 1 or data interface 2 shown in the figure) connected with the wireless network card 10; Fig. 3 The direction indicated by the solid arrow in the middle is the data packet forwarding direction.

Please refer to Fig. 4, this figure is that the wireless switching device of the present invention is to prevent from receiving multiple duplicate data packets due to the existence of multiple wireless network cards, and adds a specific composition block diagram of the wireless switching device of the data packet selection unit; On the basis of the specific composition and structure of the device, it further includes a data packet selection unit 30, wherein each wireless network card 10 is connected to the data exchange unit 20 through the data packet selection unit 30 respectively, and the data packet selection unit 30 is mainly used for each Select a data packet from the data packets with the same bearer data content forwarded by the wireless network cards 10 and send it to the data exchange unit 20 for processing. Wherein the wireless switching device joins the data packet selection unit 30 mainly because after adopting the wireless switching device of the present invention, as long as one of all the wireless network cards 10 connected to the data switching unit 20 has a wireless network card 10 connected to the wireless local area network system, then and The user terminal connected to the data exchange unit 20 can normally access the wireless local area network system. However, if multiple wireless network cards 10 are connected to the wireless local area network system at the same time, there will be multiple copies of the same data packet received by the user terminal from the network side, so in order to reduce the processing overhead of the data exchange unit 20 , before the data exchange unit 20 forwards the data packets, it is necessary to filter the received multiple repeated data packets, and the purpose of setting the data packet selection unit 30 is to complete this task. Of course, if the data packet selection unit 30 is not provided, simultaneously in order to reduce the processing overhead of the data exchange unit 20 in this case, it is also possible to select the processing mode of discarding these repeated data packets by the data exchange unit 20, because in this case The existence time is short, and it will only appear briefly during the switching process, so discarding the data packets in this short period of time will not affect the progress of the entire communication process.

Each wireless network card 10 mentioned above can be connected to the data exchange unit 20 through an Ethernet interface, of course, it can also be connected to the data exchange unit 20 through other forms of data interfaces, and can even be connected through a private data interface.

At the same time, the data exchange unit 20 can also be connected to the user terminal through an Ethernet interface (such as data interface 2 or 3 shown in FIG. 3 ), and of course other common data interfaces can also be selected for connection.

The wireless switching device proposed above in the present invention can be connected internally or externally to the user terminal, that is, the wireless switching device can be a part of the terminal, can be connected outside the terminal, or can be connected inside the terminal, And at least two wireless network cards must be arranged in each wireless switching device.

Correspondingly, the present invention also proposes a wireless switching method, and the wireless switching method of the present invention will be described in detail below in conjunction with the accompanying drawings. Please refer to Fig. 5, this figure is the realization principle flowchart of the wireless handover method of the present invention; Its main realization process is as follows:

Step S10, redundantly configuring at least one wireless network card for each user terminal in advance;

Step S20, when the user terminal maintains a communication connection with the original access point AP during high-speed movement, the redundantly configured wireless network cards in step S10 can search for other access points in advance before the switching process occurs. AP; wherein the redundantly configured wireless network card can search for the corresponding access point by scanning the corresponding access point status information carried in the beacon detection broadcast by different access point APs on the public channel of the wireless LAN system (this technology is in The prior art has been described, and will not be repeated here); or send an active detection frame to each access point AP, and then search for the corresponding access point AP by checking the status information fed back by each access point AP (this technology also It has been described in the prior art and will not be repeated here).

In step S30, the user terminal selects an AP among the access points AP searched in step S20 as a new access point AP to be accessed; wherein the user terminal can select an AP with the highest transmission signal strength among the searched access point APs The access point AP is used as the new access point AP to be accessed; of course, the overall quality of the signal transmitted by each access point AP can also be considered comprehensively to decide which access point AP to be selected as the access point AP to be accessed. .

In step S40, the user terminal establishes a communication connection with the access point AP selected in step S30, and disconnects the communication connection with the original access point AP. The two processing methods adopted by how to establish a communication connection between the user terminal and the access point AP have been described in detail in the prior art, and will not be repeated here.

Similarly, during the switching process of the user terminal in step S40, before the user terminal disconnects the communication connection with the original access point AP, and has already established the communication connection state with the selected access point AP, the content of the bearer data received is the same Packets will be processed as follows:

Randomly select a data packet from the received data packets with the same bearer data content for processing; or directly discard all received data packets with the same bearer data content.

At the same time, after adopting the wireless switching method of the present invention, if the wireless network card in the current working state of the user terminal fails, the follow-up work can be transferred to another wireless network card with redundant configuration to continue, so that communication interruption can be prevented .

Please refer to FIG. 6, which is a schematic diagram of a user terminal switching between multiple access points after adopting the wireless switching device and its method of the present invention; After installing the wireless switching device of the present invention, when the wireless local area network system is in a high-speed mobile state, after the coverage area of one AP enters the coverage area of another AP, it can maintain a communication connection with the original AP. Let other redundantly configured wireless network cards actively search for other access point APs. In this way, on the basis of communicating with the original AP, the search process of the AP to be switched to has been carried out synchronously. The user terminal of the device can search for other wireless LAN access points AP before the original connection is disconnected, and access the wireless LAN system through the searched AP, so this can greatly save the user terminal between different APs. time to switch between.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be It is regarded as the protection scope of the present invention.

Claims (10)

1, a kind of wireless switching device shifter is used for the wireless local network user terminal and carries out hand-off process between diverse access point, it is characterized in that, comprising:

At least two wireless network cards, each wireless network card is searched for the access point that can insert respectively; And after the access point by search is linked into WLAN (wireless local area network), and the transmitting-receiving of carrying out wireless data packet between the access point is handled; And

The exchanges data unit is connected with described user terminal with each wireless network card respectively, is used for the packet that wireless network card receives is transmitted to user terminal; And the packet that user terminal is sent is transmitted to wireless network card.

2, wireless switching device shifter according to claim 1, it is characterized in that, comprise that also packet chooses the unit, each wireless network card is chosen the unit by this packet respectively and is connected with described exchanges data unit, is used for choosing a packet and sending to the exchanges data unit and handle being transmitted the identical packet of carrying data content that comes by each wireless network card.

3, wireless switching device shifter according to claim 1 and 2 is characterized in that, described wireless network card is connected with described exchanges data unit by Ethernet interface.

4, wireless switching device shifter according to claim 1 and 2 is characterized in that, described exchanges data unit is connected with described user terminal by Ethernet interface.

5, wireless switching device shifter according to claim 1 is characterized in that, described wireless switching device shifter is connected or external connection with described user terminal is built-in.

6, a kind of wireless switching method is used for the wireless local network user terminal and carries out hand-off process between diverse access point, it is characterized in that, comprises step:

(1) is described at least one wireless network card of user terminal redundant configuration;

(2) when described user terminal kept with the communicating to connect of former access point, the wireless network card of redundant configuration was searched for other access points that can insert respectively;

(3) user terminal is chosen an access point that will insert that conduct is new in the access point that searches;

(4) described user terminal is set up and is chosen communicating to connect between the access point, and the communicating to connect of disconnection and former access point.

7, wireless switching method according to claim 6, it is characterized in that, the corresponding access point state information of carrying was searched for corresponding access point during the wireless network card of redundant configuration was detectd by the beacon of diverse access point broadcasting on the scanning common signal channel in the described step (2); Or

Send the active probe frame to each access point,, search for corresponding access point by checking the state information of each access point feedback.

8, wireless switching method according to claim 6 is characterized in that, user terminal is chosen the access point of strength of transmitted signals maximum as the new access point that will insert in the described step (3) in the access point that searches.

9, wireless switching method according to claim 6 is characterized in that, described step (4) also comprises step:

Before described user terminal pair and former access point disconnect and communicating to connect, and and choose the establish a communications link processing mode of the packet employing that the carrying data content of reception is identical state under of access point and be:

One of picked at random is handled in the identical packet of carrying data content; Or

Abandon the identical packet of all carrying data contents.

10, according to any described wireless switching method of claim of claim 6～9, it is characterized in that, described step (4) also comprises step afterwards: when user terminal breaks down at current in running order wireless network card, shift follow-up work and proceed to another wireless network card of redundant configuration.

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