CN105323826A - Wireless local area network access method, access point and terminal - Google Patents

Abstract

The invention provides a method for accessing a wireless local area network, an access point and a terminal. Wherein, in the method, the notification message sent by the AP on the channel of the first frequency band not only carries the channel information of the first frequency band, but also carries the channel information of the second frequency band that the terminal is expected to access preferentially, so that the terminal can quickly obtain And maintain the channel information on multiple frequency bands, and then when accessing the AP in the future, you can directly select the frequency band with priority access from the channel information of the maintained multiple frequency bands according to the predetermined strategy to achieve efficient and fast access. Spectrum navigation avoids repeated timeout processes or disassociation operations in the prior art, reduces spectrum navigation time and channel occupation, and improves user experience.

Description

A method for accessing a wireless local area network, an access point and a terminal

technical field

The invention relates to the technical field of wireless local area network (WLAN), in particular to a method for accessing a wireless local area network, an access point (AP) and a terminal.

Background technique

IEEE802.11n supports two frequency bands of 2.4GHz and 5.8GHz at the same time. The 2.4GHz frequency range is 2.4-2.483GHz, and there are at most three channels that do not interfere with each other at the same time, and each channel is 20MHz. The 5.8G frequency band has high frequency and rich spectrum resources (5.15GHz-5.85GHz), has 8 non-overlapping channels, and has strong anti-interference ability. Especially when deploying high-speed 802.11n networks in batches, the 802.11n protocol stipulates that 40MHz bandwidth must be used, so only one channel is available in the entire 2.4GHz frequency band. When deploying 802.11n 40MHz networks on a large scale, co-channel interference is serious, while 5.8GHz spectrum resources are abundant , which can effectively avoid the generation of co-channel interference.

At present, 2.4GHz is very common and has a large number of users, while 5.8GHz has attracted more and more attention because of its rich spectrum resources (5.15GHz to 5.85GHz) and low interference. Since 2.4GHz is widely used, there are often a large number of 802.11b/g clients in the frequency band, which may easily cause network congestion. Dual-band terminals that can work in the above two frequency bands usually select APs to access by comparing the signal strengths of the two frequency bands. The 5.8GHz frequency band has high frequency and serious signal attenuation, causing dual-band network card users to access 2.4GHz The possibility is still very high, which is likely to cause a heavy load on the 2.4GHz frequency band, while there is basically no access to the 5.8GHz frequency band.

In order to effectively utilize the 5.8GHz frequency band, many manufacturers have proposed their own spectrum navigation methods to guide dual-band terminals to preferentially access the 5.8GHz frequency band. At present, there are mainly two kinds of spectrum navigation methods commonly used:

a. The AP listens to the probe request (ProbeRequest) frame sent by the terminal on the 2.4GHz frequency band, and delays the response to the ProbeRequest, causing the ProbeRequest of the 2.4GHz frequency band of the dual-band terminal to time out, repeated many times, to guide the dual-band terminal as much as possible Send the ProbeRequest in the 5.8GHz frequency band, and then respond to the ProbeRequest in the 5.8GHz frequency band, so as to guide the dual-band terminal to the 5.8GHz frequency band.

b. The AP sends a disassociation (Disassociation) frame to reject the association request of the terminal, disassociates the association with the dual-frequency terminal in the 2.4GHz frequency band, and repeats it several times to guide the dual-frequency terminal to associate with the 5.8GHz frequency band as much as possible.

The existing spectrum navigation methods guide the terminal to access the 5.8GHz frequency band by not responding to the terminal’s association request of the 2.4GHz frequency band for a long time, or repeatedly disassociate the user’s 2.4GHz frequency band association, but the existing terminals are based on The size of the signal strength is used to select the access AP, so these methods cannot guarantee that the dual-band client will be able to successfully guide the dual-band client to access the 5.8GHz frequency band, and these methods require repeated timeout processes or disassociation operations, and the spectrum navigation takes a long time , and the channel is occupied for a long time, suppressing user bandwidth, resulting in poor user experience.

Contents of the invention

The technical problem to be solved by the embodiments of the present invention is to provide a method for accessing a wireless local area network, an access point and a terminal, so as to efficiently guide the terminal to access the wireless local area network on a predetermined frequency band.

In order to solve the above technical problems, a method for accessing a wireless local area network provided by an embodiment of the present invention is applied to a terminal, including:

The terminal receives an announcement message sent by the AP on the first channel of the first frequency band, the AP supports both the first frequency band and the second frequency band, and the announcement message carries the first frequency band of the AP on the first frequency band. channel information;

judging whether the notification message also carries information about a second channel of the AP in a second frequency band, where the second channel of the second frequency band is a channel that the AP expects the terminal to access preferentially;

When the announcement message carries information about the second channel of the AP in the second frequency band, the terminal establishes the AP, the first channel of the first frequency band, and the second frequency band according to the announcement message A list of associations between the second channels of ;

When the user chooses to access the AP, according to a preset access policy, select the second channel of the second frequency band from the association list, and access the AP on the second channel.

Among them, in the above method,

The announcement message also carries indication information for indicating whether the AP supports two frequency bands at the same time, and when the indication information indicates that the AP supports two frequency bands at the same time, the announcement message also carries the indication information that the AP expects Information about the second channel on the second frequency band that the terminal preferentially accesses;

Further, when the indication information indicates that the AP supports two frequency bands at the same time, it is determined that the announcement message carries information about the second channel of the AP in the second frequency band.

Among them, the above method also includes:

Record the signal strength of the AP in each channel in the association list;

After selecting the second channel of the second frequency band from the association list, further according to the recorded signal strength, it is judged whether the signal strength of the AP on the second channel satisfies a preset condition, and if the preset condition is met, condition, access the AP on the second channel; otherwise, access the AP on the first channel.

Among them, in the above method,

When the announcement message carries information about a second channel of the AP in a second frequency band, unicast sending a probe request frame to the AP on the second channel and receiving a probe response frame returned by the AP, Record the signal strength of the AP on the second channel in the association list according to the signal strength of the probe response frame.

Wherein, in the above method, the first frequency band is the 2.4GHz frequency band, the second frequency band is the 5.8GHz frequency band, and the notification message is the beacon frame broadcast and/or the The probe response frame returned by the AP for the probe request frame sent by the terminal on the first channel.

Wherein, in the above method, the AP uses the same service set identifier SSID on different frequency bands, and the notification message also carries the SSID of the AP on the first frequency band, and in establishing the association list, use The AP is represented by the SSID of the AP on the first frequency band.

The embodiment of the present invention also provides another method for accessing a wireless local area network, applied to an AP, including:

The AP obtains a preset policy, the AP supports both the first frequency band and the second frequency band, and the preset policy indicates that the AP preferentially accesses the terminal on the second frequency band;

When the AP sends a first notification message carrying the information of the first channel on the first channel of the first frequency band, according to the preset strategy, the AP is also carried in the first notification message Information about the second channel of the second frequency band that the terminal is expected to access preferentially, so that the terminal can establish the AP, the first channel of the first frequency band, and the second channel of the second frequency band according to the first notification message. A list of associations between two channels.

Among them, in the above method,

When the AP sends the first announcement message, it further carries indication information for indicating whether the AP supports two frequency bands at the same time in the first announcement message.

Among them, the above method also includes:

The AP sends a second notification message carrying information of the second channel on a second channel of the second frequency band, and the second notification message does not carry channel information of other frequency bands other than the second frequency band.

Among them, the above method also includes:

The first notification message sent by the AP also carries the SSID on the first frequency band, and the second notification message sent also carries the SSID on the second frequency band, wherein the SSID on the first frequency band is the same as the second frequency band. The SSID is the same on the frequency band.

The embodiment of the present invention also provides a terminal, including:

The receiving unit is configured to receive an announcement message sent by the AP on the first channel of the first frequency band, the AP supports the first frequency band and the second frequency band at the same time, and the announcement message carries the information of the AP on the first frequency band information on the first channel;

A judging unit, configured to judge whether the notification message also carries information about a second channel of the AP in a second frequency band, where the second channel of the second frequency band is a channel that the AP expects the terminal to access preferentially;

An establishment unit, configured to, when the announcement message carries information about the second channel of the AP in the second frequency band, establish the AP, the first channel of the first frequency band, and the An association list between the second channels of the second frequency band;

An access unit, configured to select a second channel of the second frequency band from the association list according to a preset access strategy when the user chooses to access the AP, and access the AP on the second channel. Said AP.

Among them, in the above terminal,

The announcement message also carries indication information for indicating whether the AP supports two frequency bands at the same time, and when the indication information indicates that the AP supports two frequency bands at the same time, the announcement message also carries the indication information that the AP expects Information about the second channel on the second frequency band that the terminal preferentially accesses;

The judging unit is further configured to judge that the announcement message carries information of a second channel of the AP in the second frequency band when the indication information indicates that the AP supports two frequency bands at the same time.

Among them, in the above terminal,

The establishment unit is also used to record the signal strength of the AP in each channel in the association list;

The access unit is further configured to, after selecting the second channel of the second frequency band from the association list, further judge whether the signal strength of the AP on the second channel meets the predetermined signal strength according to the recorded signal strength. A condition is set, and when the preset condition is met, the AP is accessed on the second channel; otherwise, the AP is accessed on the first channel.

Among them, in the above terminal,

The establishing unit is further configured to, when the notification message carries information about a second channel of the AP in the second frequency band, unicast send a probe request frame to the AP on the second channel and receive the According to the probe response frame returned by the AP, record the signal strength of the AP on the second channel in the association list according to the signal strength of the probe response frame.

Wherein, in the above-mentioned terminal, the first frequency band is the 2.4GHz frequency band, the second frequency band is the 5.8GHz frequency band, and the notification message is the beacon frame broadcast and/or the The probe response frame returned by the AP for the probe request frame sent by the terminal on the first channel.

Wherein, in the above-mentioned terminal, the AP uses the same service set identifier SSID on different frequency bands, and the notification message also carries the SSID of the AP on the first frequency band;

The establishing unit is further configured to use the SSID of the AP on the first frequency band to represent the AP when establishing the association list.

The embodiment of the present invention also provides an AP, the AP supports the first frequency band and the second frequency band at the same time, and the AP includes:

a policy unit, configured to obtain a preset policy, the preset policy instructing the AP to preferentially access the terminal on the second frequency band;

The first sending unit is configured to, when sending a first notification message carrying information of the first channel on the first channel of the first frequency band, according to the preset strategy, in the first notification message Carrying information about the second channel of the second frequency band that the AP expects the terminal to access preferentially, so that the terminal establishes the AP, the first channel of the first frequency band, and the second channel according to the first notification message. An association list between the second channels of the two frequency bands.

Among them, among the above APs,

The first sending unit is further configured to, when sending the first notification message, further carry indication information for indicating whether the AP supports two frequency bands at the same time in the first notification message.

Among them, the above AP also includes:

The second sending unit is configured to send a second notification message carrying information of the second channel on a second channel of a second frequency band, and the second notification message does not carry other frequency bands other than the second frequency band channel information.

Among them, among the above APs,

The first sending unit is further configured to carry the SSID on the first frequency band in the sent first notification message;

The second sending unit is further configured to carry the SSID on the second frequency band in the sent second announcement message;

Wherein, the SSID on the first frequency band is the same as the SSID on the second frequency band.

Compared with the prior art, the method for accessing the wireless local area network, the access point and the terminal provided by the embodiments of the present invention have at least the following beneficial effects: the announcement message sent by the AP on the channel of the first frequency band not only carries the second The channel information of the first frequency band also carries the channel information of the second frequency band that the terminal is expected to access preferentially, so that the terminal can quickly obtain and maintain the channel information on multiple frequency bands, and then when accessing the AP in the future, according to the predetermined strategy, in the Among the channel information of multiple frequency bands maintained, the frequency band with priority access is directly selected for access, which realizes efficient and fast spectrum navigation, avoids the repeated timeout process or disassociation operation of the prior art, and reduces the frequency spectrum Navigation time and channel occupancy improve user experience. Moreover, the embodiment of the present invention guides the terminal to preferentially access the 5.8GHz frequency band, so that the high-capacity 5.8GHz frequency band can be better utilized, effectively improving the spectrum utilization efficiency of the network, and ensuring high user throughput.

Description of drawings

FIG. 1 is a schematic flowchart of a method for accessing a wireless local area network provided by an embodiment of the present invention;

FIG. 2 is a schematic flowchart of a method for accessing a wireless local area network provided by another embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a terminal provided by an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of an AP provided by an embodiment of the present invention;

FIG. 5 is a schematic diagram of message interaction between a terminal and an AP in an example of the present invention;

FIG. 6 is an extended schematic diagram of the ExtendedCapabilities field in an example of the present invention;

FIG. 7 is an extended schematic diagram of the VendorSpecific field in an example of the present invention;

Fig. 8 is a schematic diagram of an application environment of the method for accessing a network in an example of the present invention.

detailed description

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will describe in detail with reference to the drawings and specific embodiments.

In the embodiment of the present invention, both the terminal and the AP can work in at least two frequency bands. In order to improve spectrum navigation efficiency, an embodiment of the present invention provides a method for accessing a wireless local area network, which can efficiently guide a terminal to access a wireless local area network in a predetermined frequency band, and improve user experience. The following will describe respectively from the terminal side and the AP side.

First, taking a terminal as an example, the method for accessing a wireless local area network provided by the embodiment of the present invention is applied to a terminal that supports dual-frequency access, that is, the terminal can work in two frequency bands, and can access APs on these frequency bands. . As shown in Figure 1, the method provided by the embodiment of the present invention includes the following steps:

Step 11, the terminal receives an announcement message sent by the AP on the first channel of the first frequency band, the AP supports the first frequency band and the second frequency band at the same time, and the announcement message carries the information of the AP on the first frequency band information of the first channel.

Here, the AP supports both the first frequency band and the second frequency band, and can work on the first channel of the first frequency band and the second channel of the second frequency band. The notification message carries information about the first channel of the AP on the first frequency band, and may also carry a service set identifier (SSID, ServiceSetIdentifier) of the AP on the first frequency band.

Specifically, the announcement message may be a beacon (Beacon) frame broadcast and sent by the AP on the first channel, and the beacon frame carries the SSID of the AP on the first frequency band and the SSID of the AP on the first frequency band. Information on the first channel. The notification message may also be a probe response (Proberesponse) frame sent by the AP to the terminal in unicast in response to the scanning of the terminal on the first channel of the first frequency band. The terminal scans on each channel of the first frequency band, and broadcasts and sends a probe request (ProbeRequest) frame respectively; after the AP receives the above-mentioned probe request frame on the first channel it works on, it will unicast a probe response frame to the terminal. It carries information about the SSID of the AP on the first frequency band and the first channel of the AP on the first frequency band.

As a preferred implementation manner, in the embodiment of the present invention, the AP may use the same SSID in different frequency bands. In WLAN, the terminal identifies the AP according to the SSID. In the embodiment of the present invention, the AP uses the same SSID on different frequency bands, so that when the terminal receives messages on different frequency bands, it can directly determine whether these messages carry the same SSID. to identify whether these messages are from the same AP.

Step 12, judging whether the notification message also carries the information of the second channel of the AP in the second frequency band, and the second channel of the second frequency band is a channel that the AP expects the terminal to access preferentially.

The embodiment of the present invention improves the above notification message in the prior art. In the prior art, the notification message only carries relevant information of the current channel. In the embodiment of the present invention, the notification message may carry channel information of other frequency bands other than the current channel. So that the terminal can quickly obtain relevant information of the channel and other channels according to the notification message received on the channel. In order to be compatible with the existing technology, the terminal judges in this step whether the notification message carries relevant information of other channels, and if so, proceeds to step 13; otherwise, it can be processed according to the processing method of the prior art.

In order to facilitate identification of whether the notification message carries information about other channels, in the embodiment of the present invention, the notification message may carry indication information indicating whether the AP supports two or more frequency bands at the same time, and the indication information indicates the When the AP supports more than two frequency bands at the same time, the notification message also carries information about the second channel of the AP on the second frequency band. In this way, in step 12, when the indication information in the notification message indicates that the AP supports more than two frequency bands at the same time, the terminal may determine that the notification message carries the information of the second frequency band that the AP expects the terminal to access preferentially. Information on the second channel.

Step 13: When the notification message carries information about the second channel of the AP in the second frequency band, according to the notification message, establish the AP, the first channel of the first frequency band, and the second channel of the first frequency band. An association list between the second channels of the two frequency bands.

In this step 13, the terminal can quickly establish the association relationship between the AP, the first channel and the second channel directly according to the notification message received on the first channel, without waiting for the scanning on the second channel.

In the embodiment of the present invention, if the APs use the same SSID on different frequency bands, then in establishing the association list, the SSID of the AP on the first frequency band (same as the SSID of the second frequency band) can be directly used. ) to represent the AP to simplify the characterization of AP. In this way, when the user wants to access the wireless local area network through the AP, he only needs to select the AP from the association list of each AP obtained by the terminal, and the APs in the association list can directly use the AP's SSID to represent.

Step 14, when the user chooses to access the AP, select a second channel of the second frequency band from the association list according to a preset access strategy, and access the AP on the second channel.

In this step, the terminal may display the above association list to the user, and the association list shows the user that the AP can work on the first frequency band and the second frequency band. When multiple APs are scanned by the terminal, the associated list of multiple APs may be displayed to the user at the same time. Users can select an AP they want to access in these association lists. When the user chooses to access the network through a certain AP, in order to guide the terminal to preferentially access a certain frequency band, such as the second frequency band that the AP expects the terminal to access preferentially, it can be guided by a preset access policy, for example, the The policy indicates to use the frequency band that the AP expects the terminal to access preferentially, so the terminal selects and accesses the second channel of the second frequency band from the association list of the AP according to the policy. Subsequent terminals can access the AP through authentication and association procedures according to the procedures of the prior art.

In the above method, in order to guide the terminal to preferentially access the wireless local area network through the 5.8GHz frequency band, the first frequency band may be the 2.4GHz frequency band, and the second frequency band may be the 5.8GHz frequency band. When there is a 5.8GHz frequency band, access through the 5.8GHz frequency band is preferred. In this way, in step 14, according to the strategy, the terminal will directly unicast the authentication frame and the association frame to the corresponding AP on the 5.8GHz frequency band, so as to realize the priority access on the 5.8GHz frequency band.

Considering the requirements for channel signal strength, the embodiment of the present invention can pre-record the signal strength information of the AP on the channel of each frequency band, so that in the above step 14, after selecting the second channel of the second frequency band, further according to According to the recorded signal strength, it is judged whether the signal strength of the AP on the second channel meets the preset condition, and when the preset condition is met, the AP is connected on the second channel; otherwise, the AP is connected on the first channel The AP, of course, also needs to judge whether the signal strength of the AP on the first channel meets the requirements before accessing on the first channel, and if so, start the access process, otherwise, prompt the user that the signal quality of the AP cannot meet Access requirements.

In the embodiment of the present invention, the signal strength of the AP on each channel can be directly recorded in the association list. Specifically, in step 11, the terminal may determine the signal strength of the AP on the first channel according to the received notification message sent by the AP on the first channel in the first frequency band. In step 13, when it is determined that the notification message carries the information of the second channel of the AP in the second frequency band, the terminal may immediately unicast a probe request frame to the AP on the second channel, and then receiving the probe response frame returned by the AP, and recording the signal strength of the AP on the second channel in the association list according to the signal strength of the probe response frame. Thus, the terminal can maintain the signal strength of the channel of each channel in the association list.

The above method illustrates how the embodiment of the present invention guides the terminal to preferentially access the AP in the 5.8GHz frequency band. It can be seen that the notification message sent by the AP on the channel of the first frequency band not only carries the channel information of the first frequency band , also carries the channel information of the second frequency band that the terminal is expected to access preferentially, so that the terminal can quickly obtain and maintain the channel information on multiple frequency bands, and then when the subsequent terminal accesses the AP, according to the predetermined strategy, the channel information in the maintained multiple Among the channel information of each frequency band, the frequency band with priority access is directly selected for access, which realizes efficient and fast spectrum navigation, avoids the repeated timeout process or disassociation operation of the prior art, and reduces the spectrum navigation time and channel occupancy, improving the user experience. In the embodiment of the present invention, the terminal is guided to preferentially access the 5.8 GHz frequency band, so that the high-capacity 5.8 GHz frequency band can be better utilized, the frequency spectrum utilization efficiency of the network is effectively improved, and high throughput of users is ensured.

The method for accessing a wireless local area network according to an embodiment of the present invention will be described below from an AP side, and the AP supports working on two frequency bands (a first frequency band and a second frequency band) at the same time. As shown in Figure 2, when the method is applied to an AP, it includes steps:

In step 21, the AP acquires a preset policy, the AP supports both the first frequency band and the second frequency band, and the preset policy instructs the AP to preferentially access the terminal on the second frequency band.

Step 22, when the AP sends a first announcement message carrying information of the first channel on the first channel of the first frequency band, according to the preset strategy, the first announcement message carries Information about the second channel of the second frequency band that the AP expects the terminal to access preferentially, so that the terminal establishes the AP, the first channel of the first frequency band, and the second channel according to the first notification message. A list of associations between the second channels of the frequency band.

Through the above steps, the terminal can be made to establish the association list, and then when accessing the AP, the second channel of the second frequency band that is preferentially accessed in the list is preferentially used for access.

In the embodiment of the present invention, in the above step 22, when the AP sends the first announcement message, it may also carry indication information indicating whether the AP supports two frequency bands at the same time in the first announcement message, In order for the terminal to quickly judge whether the notification message carries channel information of the second frequency band according to the indication information.

Similar to the prior art, the terminal may also send a second notification message on the second channel of the second frequency band, and at this time, the notification message carries the second notification message of the information of the second channel, but does not carry other notification messages. The channel, such as the information of the first channel of the first frequency band.

The above-mentioned first notification message and second notification message may specifically be a beacon frame periodically broadcast by the AP, or a probe response frame unicast and fed back by the AP for the terminal scanning on a specific channel.

As a preferred implementation manner, the APs all use the same SSID in different frequency bands. The first notification message sent by the AP also carries the SSID on the first frequency band, and the second notification message sent also carries the SSID on the second frequency band. Since the SSIDs of each frequency band are the same, the above notification The SSID on the first band in the message is the same as the SSID on the second band.

The above respectively explains how the method described in the embodiment of the present invention is applied to the terminal and the AP. Based on the above method, an embodiment of the present invention provides a terminal and an AP for implementing the above method. Referring to Figure 3, the terminal provided by the embodiment of the present invention includes:

The receiving unit 31 is configured to receive an announcement message sent by the AP on the first channel of the first frequency band, the AP supports the first frequency band and the second frequency band at the same time, and the announcement message carries the information of the AP on the first frequency band the information of the first channel;

A judging unit 32, configured to judge whether the notification message also carries information about a second channel of the AP in a second frequency band, where the second channel of the second frequency band is a channel that the AP expects the terminal to access preferentially;

The establishing unit 33 is configured to, when the announcement message carries information about the second channel of the AP in the second frequency band, according to the announcement message, establish the AP, the first channel of the first frequency band, and a list of associations between second channels in the second frequency band;

The access unit 34 is configured to select a second channel of the second frequency band from the association list according to a preset access policy when the user chooses to access the AP, and access the second channel on the second channel The AP.

In the embodiment of the present invention, the announcement message also carries indication information indicating whether the AP supports two frequency bands at the same time, and when the indication information indicates that the AP supports two frequency bands at the same time, the announcement message also carries It carries the information of the second channel on the second frequency band that the AP expects the terminal to access preferentially. The judging unit 32 is further configured to judge that the notification message carries information about the second channel of the AP in the second frequency band when the indication information indicates that the AP supports two frequency bands at the same time.

In order to judge whether the channel of the access frequency band meets the preset requirement, in the embodiment of the present invention, the establishment unit 33 is further configured to record the signal strength of the AP in each channel in the association list. The access unit 34 is further configured to, after selecting the second channel of the second frequency band from the association list, further judge whether the signal strength of the AP on the second channel meets the requirements of the recorded signal strength. A preset condition, when the preset condition is met, the AP is accessed on the second channel; otherwise, the AP is accessed on the first channel.

Specifically, the establishment unit 33 is further configured to, when the notification message carries information about the second channel of the AP in the second frequency band, unicast a detection request to the AP on the second channel frame and receive a probe response frame returned by the AP, and record the signal strength of the AP on the second channel in the association list according to the signal strength of the probe response frame.

In order to preferentially guide the terminal to access on the 5.8GHz frequency band, the first frequency band is the 2.4GHz frequency band, the second frequency band is the 5.8GHz frequency band, and the announcement message is a beacon sent by the AP broadcast on the first channel frame and/or the probe response frame returned by the AP with respect to the probe request frame sent by the terminal on the first channel.

As a preferred implementation manner, in the embodiment of the present invention, the AP uses the same SSID in different frequency bands, and the notification message also carries the SSID of the AP in the first frequency band. The establishing unit 33 is further configured to use the SSID of the AP on the first frequency band to represent the AP when establishing the association list.

The embodiment of the present invention also provides an AP, the AP supports both the first frequency band and the second frequency band, please refer to Figure 4, including:

A policy unit 41, configured to obtain a preset policy, the preset policy instructs the AP to preferentially access the terminal on the second frequency band;

The first sending unit 42 is configured to, when sending a first notification message carrying information of the first channel on a first channel of a first frequency band, according to the preset policy, in the first notification message carry the information of the second channel of the second frequency band that the AP expects the terminal to access preferentially, so that the terminal can establish the AP, the first channel of the first frequency band, and the A list of associations between second channels of the second frequency band.

The second sending unit 42 is configured to send a second notification message carrying information of the second channel on a second channel of the second frequency band, and the second notification message does not carry other notification messages outside the second frequency band. Channel information for the frequency band.

Here, the first sending unit 42 is further configured to, when sending the first notification message, further carry indication information in the first notification message for indicating whether the AP supports two frequency bands at the same time.

The first sending unit 42 is further configured to carry the SSID on the first frequency band in the sent first announcement message. The second sending unit 43 is further configured to carry the SSID on the second frequency band in the sent second announcement message. Wherein, the SSID on the first frequency band is the same as the SSID on the second frequency band.

The above embodiments are described by taking two frequency bands (the first frequency band and the second frequency band as an example). The present invention is not limited to the case of two frequency bands. The AP in the present invention can support more than two frequency bands at the same time, and the AP can also set the desired frequency band for priority access. In this way, when sending the above notification message on the frequency band of non-priority access, it can carry the priority frequency band at the same time. Access to information about channels in the frequency band, so that the terminal establishes the above-mentioned association relationship, and then selects the channel access of the frequency band that the AP expects to access preferentially during subsequent access.

Finally, the present invention will be described in more detail through a specific example in conjunction with guiding terminals to preferentially access the 5.8GHz frequency band under the 802.11n architecture.

In this example, the AP actively announces its dual-band characteristics, and the terminal (STA) preferentially accesses the 5.8GHz frequency band according to a certain algorithm, which can make better use of the high-capacity 5.8GHz frequency band, effectively improve the spectrum utilization efficiency of the network, and ensure that users high throughput. To achieve the above purpose, this example adopts the following technical solutions:

When the smart spectrum navigation function is enabled on the AP, the AP notifies the surrounding STAs of its dual-frequency mode function through Beacon frames or Proberesponse frames at 2.4GHz, and notifies the working channel information of the 5.8GHz frequency band with the same SSID as the 2.4GHz frequency band. After receiving the notification above, the STA generates an SSID scan list of the two frequency bands. If the 5.8GHz frequency band meets the basic communication requirements, it starts the corresponding state machine and sends a ProbeRequest unicast frame to the designated channel of the 5.8GHz frequency band that it wishes to associate with. The AP carries the detailed configuration information of the 5.8GHz channel in the ProbeResponse frame and sends it back to the STA, and the terminal then completes the scan. Subsequently, the STA performs authentication and association with the designated 5.8GHz frequency band. The specific interaction process is shown in Figure 5. The dotted line in Figure 5 indicates that either Beacon frame or Probe frame can be selected. On the 2.4GHz frequency band Notify the STA of the working channel information of the 5.8GHz frequency band. The specific workflow of this example is as follows:

This example provides the 5.8G priority access method under the 802.11n architecture. The specific workflow is as follows:

1. The AP announces that the dual-band function is enabled

The IEEEStd802.11-2012 standard stipulates that a network performance field can be added to the ExtendedCapabilities information element to notify the STA of the performance of the network. The STA can judge whether it can access the network according to these performance fields. Therefore, in order to ensure the specification of the frame format and consistency, choose to use the second reserved field of the Capabilities field of the ExtendedCapabilities information element as the announcement field of dual-frequency performance (that is, the Doublefrequency field). When this field is set to 0, it means that it only supports 2.4GHz; when it is set to 1, it means Both 2.4GHz and 5.8GHz frequency bands are supported. The positions of the Doublefrequency field bits in the ExtendedCapabilities information element are shown in Figure 6.

In addition to announcing that the dual-band function is supported, the AP also needs to announce the channel used by the 5.8G SSID with the same name as the 2.4G SSID. For this reason, the current channel notification field of the 5.8G frequency band is added in the VendorSpecific field, and the channel used by the 2.4G frequency band is still Notified through the DSParameterSet field. The added VerdorSpecific format is shown in Figure 7, where the ElementID is filled with the reserved value of ElementID 17; the Length is filled with 1; the OFDMParameterSet field is filled with 1, indicating that the function of this information element is to announce the channel used by the 5.8G frequency band, and the filling is 0. Indicates that the 5.8G frequency band is not enabled temporarily, and the following fields can be ignored; Currentchannel fills the channel currently used by the 5.8G frequency band.

If the STA is actively scanning, the ProbeResponse frame sent by the AP uses the same field filling method as the above-mentioned Beacon.

2. STA scanning process

Before joining the network, the STA first scans the network. During the scanning process, it can passively receive Beacon frames, or actively broadcast and send ProbeRequest frames to obtain Proberesponse frames returned by the AP.

In passive mode, STA obtains SSID information by monitoring Beacon packets on 2.4G. If the received beacon has a dual-frequency attribute, send a unicast proberequest message on the 5.8G channel announced by the dual-frequency attribute, and confirm the relevant information through the received proberesponse message to complete the establishment of the 5.8GSSID entry. The passive scanning process of 5.8G is consistent with the normal mode.

In active mode, STA sends proberequest frame on 2.4G and obtains SSID information through the received proberesponse frame. If the received proberesponse frame has dual-frequency attribute, it will send unicast on the 5.8G channel advertised by the dual-frequency attribute proberequest frame, and confirm the relevant information through the received proberesponse frame, and complete the establishment of the 5.8GSSID entry. The active scanning process of 5.8G is consistent with the normal mode.

After scanning, two SSID association lists are generated, so that all SSIDs found and their related parameters can be listed, and one list stores SSIDs in the 2.4G frequency band and their related parameters (such as signal strength, supported rate set, country code, etc.) , the other stores the SSID and related parameters of the 5.8G frequency band. The schematic diagram is shown in Figure 8. AP1, AP2, and AP3 in Figure 8 all represent SSIDs. The channels and related parameters below are displayed on the same line in the list.

3. 5.8G preferred

When a user accesses a wireless local area network, for example, chooses to access AP1, the STA first finds the SSID in the 5.8G frequency band association list, and judges whether its signal strength meets the preset communication requirements. If it meets the requirements, it selects 5.8GHz channel access, if not satisfied, then search the 2.4G frequency band association list, select the corresponding AP access.

The above description is 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, these improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (20)

1. A method for accessing a wireless local area network, applied to a terminal, characterized in that it comprises: The terminal receives an announcement message sent by the AP on the first channel of the first frequency band, the AP supports both the first frequency band and the second frequency band, and the announcement message carries the first frequency band of the AP on the first frequency band. channel information; judging whether the notification message also carries information about a second channel of the AP in a second frequency band, where the second channel of the second frequency band is a channel that the AP expects the terminal to access preferentially; When the announcement message carries information about the second channel of the AP in the second frequency band, the terminal establishes the AP, the first channel of the first frequency band, and the second frequency band according to the announcement message A list of associations between the second channels of ; When the user chooses to access the AP, according to a preset access policy, select the second channel of the second frequency band from the association list, and access the AP on the second channel. 2. The method of claim 1, wherein The announcement message also carries indication information for indicating whether the AP supports two frequency bands at the same time, and when the indication information indicates that the AP supports two frequency bands at the same time, the announcement message also carries the indication information that the AP expects Information about the second channel on the second frequency band that the terminal preferentially accesses; Further, when the indication information indicates that the AP supports two frequency bands at the same time, it is determined that the announcement message carries information about the second channel of the AP in the second frequency band. 3. The method of claim 1, further comprising: Record the signal strength of the AP in each channel in the association list; After selecting the second channel of the second frequency band from the association list, further according to the recorded signal strength, it is judged whether the signal strength of the AP on the second channel satisfies a preset condition, and if the preset condition is met, condition, access the AP on the second channel; otherwise, access the AP on the first channel. 4. The method of claim 3, wherein, When the announcement message carries information about a second channel of the AP in a second frequency band, unicast sending a probe request frame to the AP on the second channel and receiving a probe response frame returned by the AP, Record the signal strength of the AP on the second channel in the association list according to the signal strength of the probe response frame. 5. The method according to claim 1, wherein the first frequency band is a 2.4GHz frequency band, the second frequency band is a 5.8GHz frequency band, and the announcement message is broadcast and sent by the AP on the first channel The beacon frame and/or the probe response frame returned by the AP in response to the probe request frame sent by the terminal on the first channel. 6. The method according to claim 1, wherein the AP uses the same service set identifier (SSID) on different frequency bands, and the notification message also carries the SSID of the AP on the first frequency band, In establishing the association list, the SSID of the AP on the first frequency band is used to represent the AP. 7. A method for accessing a wireless local area network, applied to an AP, comprising: The AP obtains a preset policy, the AP supports both the first frequency band and the second frequency band, and the preset policy indicates that the AP preferentially accesses the terminal on the second frequency band; When the AP sends a first notification message carrying the information of the first channel on the first channel of the first frequency band, according to the preset strategy, the AP is also carried in the first notification message Information about the second channel of the second frequency band that the terminal is expected to access preferentially, so that the terminal can establish the AP, the first channel of the first frequency band, and the second channel of the second frequency band according to the first notification message. A list of associations between two channels. 8. The method of claim 7, wherein, When the AP sends the first announcement message, it further carries indication information for indicating whether the AP supports two frequency bands at the same time in the first announcement message. 9. The method of claim 7, further comprising: The AP sends a second notification message carrying information of the second channel on a second channel of the second frequency band, and the second notification message does not carry channel information of other frequency bands other than the second frequency band. 10. The method of claim 9, further comprising: The first notification message sent by the AP also carries the SSID on the first frequency band, and the second notification message sent also carries the SSID on the second frequency band, wherein the SSID on the first frequency band is the same as the second frequency band. The SSID is the same on the frequency band. 11. A terminal, characterized in that, comprising: The receiving unit is configured to receive an announcement message sent by the AP on the first channel of the first frequency band, the AP supports the first frequency band and the second frequency band at the same time, and the announcement message carries the information of the AP on the first frequency band information on the first channel; A judging unit, configured to judge whether the notification message also carries information about a second channel of the AP in a second frequency band, where the second channel of the second frequency band is a channel that the AP expects the terminal to access preferentially; An establishment unit, configured to, when the announcement message carries information about the second channel of the AP in the second frequency band, establish the AP, the first channel of the first frequency band, and the An association list between the second channels of the second frequency band; An access unit, configured to select a second channel of the second frequency band from the association list according to a preset access strategy when the user chooses to access the AP, and access the AP on the second channel. Said AP. 12. The terminal according to claim 11, characterized in that, The announcement message also carries indication information for indicating whether the AP supports two frequency bands at the same time, and when the indication information indicates that the AP supports two frequency bands at the same time, the announcement message also carries the indication information that the AP expects Information about the second channel on the second frequency band that the terminal preferentially accesses; The judging unit is further configured to judge that the announcement message carries information of a second channel of the AP in the second frequency band when the indication information indicates that the AP supports two frequency bands at the same time. 13. The terminal according to claim 11, characterized in that, The establishment unit is also used to record the signal strength of the AP in each channel in the association list; The access unit is further configured to, after selecting the second channel of the second frequency band from the association list, further judge whether the signal strength of the AP on the second channel meets the predetermined signal strength according to the recorded signal strength. A condition is set, and when the preset condition is met, the AP is accessed on the second channel; otherwise, the AP is accessed on the first channel. 14. The terminal according to claim 13, characterized in that, The establishing unit is further configured to, when the notification message carries information about a second channel of the AP in the second frequency band, unicast send a probe request frame to the AP on the second channel and receive the According to the probe response frame returned by the AP, record the signal strength of the AP on the second channel in the association list according to the signal strength of the probe response frame. 15. The terminal according to claim 11, wherein the first frequency band is a 2.4GHz frequency band, the second frequency band is a 5.8GHz frequency band, and the notification message is broadcast and sent by the AP on the first channel The beacon frame and/or the probe response frame returned by the AP in response to the probe request frame sent by the terminal on the first channel. 16. The terminal according to claim 11, characterized in that, The AP uses the same SSID on different frequency bands, and the notification message also carries the SSID of the AP on the first frequency band; The establishing unit is further configured to use the SSID of the AP on the first frequency band to represent the AP when establishing the association list. 17. An AP, the AP supports both the first frequency band and the second frequency band, characterized in that the AP includes: a policy unit, configured to obtain a preset policy, the preset policy instructing the AP to preferentially access the terminal on the second frequency band; The first sending unit is configured to, when sending a first notification message carrying information of the first channel on the first channel of the first frequency band, according to the preset strategy, in the first notification message Carrying information about the second channel of the second frequency band that the AP expects the terminal to access preferentially, so that the terminal establishes the AP, the first channel of the first frequency band, and the second channel according to the first notification message. An association list between the second channels of the two frequency bands. 18. The AP of claim 17, wherein The first sending unit is further configured to, when sending the first notification message, further carry indication information for indicating whether the AP supports two frequency bands at the same time in the first notification message. 19. The AP according to claim 17, further comprising: The second sending unit is configured to send a second notification message carrying information of the second channel on a second channel of a second frequency band, and the second notification message does not carry other frequency bands other than the second frequency band channel information. 20. The AP of claim 19, wherein The first sending unit is further configured to carry the SSID on the first frequency band in the sent first notification message; The second sending unit is further configured to carry the SSID on the second frequency band in the sent second notification message; Wherein, the SSID on the first frequency band is the same as the SSID on the second frequency band.