CN107734669B

CN107734669B - Communication method, communication device, access point and station of wireless local area network

Info

Publication number: CN107734669B
Application number: CN201610664295.1A
Authority: CN
Inventors: 董贤东
Original assignee: Meizu Technology Co Ltd
Current assignee: Meizu Technology Co Ltd
Priority date: 2016-08-12
Filing date: 2016-08-12
Publication date: 2021-06-29
Anticipated expiration: 2036-08-12
Also published as: CN107734669A

Abstract

The invention provides a communication method, a communication device, an access point and a station of a wireless local area network, wherein the communication method of the wireless local area network comprises the following steps: generating an MU-RTS frame, wherein the MU-RTS frame comprises resource block information which is distributed to each group of stations supporting the OFDMA function and is used for feeding back a CTS frame, and the MU-RTS frame comprises the number of buffered downlink data frames which are to be continuously sent to each group of stations; transmitting the MU-RTS frame; and after receiving the CTS frame fed back by any group of stations, continuously sending the buffered downlink data frame to each station in any group of stations. The technical scheme of the invention ensures that the OFDMA technology is reasonably applied in the continuous transmission process of the cached downlink data frames, effectively improves the utilization efficiency of the frequency spectrum and meets the communication requirement of 802.11 ax.

Description

Communication method, communication device, access point and station of wireless local area network

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a communication method of a wireless local area network, a communication apparatus of a wireless local area network, an access point, and a station.

Background

In 5 months in 2013, 802.11 has established a research group HEW (High efficiency Wireless local area network) of the next generation Wi-Fi (Wireless Fidelity) technology, namely 802.11ax, and the main research points are to improve the throughput of the existing Wi-Fi technology, improve the effective utilization efficiency and the quality of service (quality of service) of the frequency spectrum, and realize a more intensive communication environment than the existing Wi-Fi technology.

In the existing Wi-Fi standard, a station receives downlink cache data through a TIM (Traffic Indication Map) mechanism, which specifically includes: a station in a PS (Power Saving) state determines whether an AP (Access Point) has downlink data buffered by receiving a TIM message in a Beacon frame, and if so, the station sends a PS-Poll (Power Saving round robin frame) to the AP in a Contention mode during a CP (Contention Period) to obtain the downlink data, and the station is in an Awake state during a CFP (Contention-free Period) until receiving the downlink data. As shown in fig. 1, the PS-Poll sent by the station to the AP and the data sent by the AP to the station are both sent in a unicast manner, and the sent data frame is also a single data frame.

OFDMA (Orthogonal Frequency Division Multiple Access) technology is adopted in 802.11ax to improve the spectrum utilization efficiency. In 802.11ax, there may be multiple data frames buffered by the AP for multiple stations, so if the buffered single downlink data frame is transmitted to the station in PS state in 802.11ax by means of unicast, it is obviously against the vision of 802.11 ax.

Disclosure of Invention

Based on at least one of the above technical problems, the present invention provides a new communication scheme for wireless local area networks, which ensures that the OFDMA technology is reasonably applied in the continuous transmission process of buffered downlink data frames, effectively improves the utilization efficiency of frequency spectrum, and meets the communication requirements of 802.11 ax.

In view of the above, according to a first aspect of the present invention, a communication method of a wireless local area network is provided, including: generating an MU (Multi-User ) -RTS (Request To Send) frame, wherein the MU-RTS frame comprises resource block information which is distributed To each group of stations supporting an OFDMA function and used for feeding back a CTS (Clear To Send) frame, and the MU-RTS frame comprises the number of buffered downlink data frames which are To be continuously sent To each group of stations; transmitting the MU-RTS frame; and after receiving the CTS frame fed back by any group of stations, continuously sending the buffered downlink data frame to each station in any group of stations.

In the technical scheme, the access point allocates resource block information to each group of stations supporting the OFDMA function by generating an MU-RTS frame, so that the stations can feed back a CTS frame to the access point according to the resource block information, and the access point can continuously send a buffered downlink data frame to each group of stations by using the OFDMA technique (e.g., in a multicast manner). Meanwhile, the generated MU-RTS frame contains the number of the buffered downlink data frames to be continuously sent to each group of stations, so that the stations can determine the number of the buffered downlink data frames to be continuously received, and the buffered downlink data frames to be continuously sent by the access point can be conveniently received. Therefore, the technical scheme of the invention ensures that the OFDMA technology is reasonably applied in the continuous transmission process of the buffer downlink data frame by adopting the MU-RTS and CTS mechanism between the access point and the site supporting the OFDMA function, effectively improves the utilization efficiency of the frequency spectrum and meets the communication requirement of 802.11 ax.

Wherein, the resource block information includes: SS (Spatial Stream) information, BW (Bandwidth), and start frequency and end frequency assigned to each station. The resource block information is not only used for the station to receive the buffered downlink data frame, but also used for the station to reply a CTS frame and an acknowledgement message frame (such as M-BA) to the access point.

Further, the MU-RTS is sent during the CP, and the MU-RTS frame may also protect the communication process between the subsequent station and the AP, that is, protect the communication process in which the station receives the buffered downlink data and the station replies the acknowledgment message frame to the AP, and also protect the station to unicast the CTS frame sent to the access point.

In the foregoing technical solution, preferably, before the step of sending the MU-RTS frame, the method further includes: generating a message frame, wherein the message frame comprises indication information and grouping information, the indication information is used for indicating that a plurality of sites supporting an OFDMA function have downlink data to be sent, which is cached by an access point, within a specified time, and the grouping information is used for indicating the grouping condition of the plurality of sites; and sending the message frame.

In the technical scheme, the access point generates the message frame, and the indication information in the message frame can indicate that the access point has the cached downlink data to be sent in the specified time to the plurality of sites supporting the OFDMA function, so that for the plurality of sites supporting the OFDMA function, the access point can adopt the OFDMA technology to transmit the cached downlink data with the sites, the application of the OFDMA technology in the transmission process of the cached downlink data is ensured, and the utilization efficiency of the frequency spectrum is effectively improved; and the message frame contains the grouping information, so that the access point can inform the station of the grouping condition after grouping a plurality of stations, and the access point can conveniently send the cached downlink data to the station in a multicast mode. Wherein the access point may group the plurality of stations supporting OFDMA functionality according to the number of the stations.

In the foregoing technical solution, preferably, the message frame is a beacon frame, and the Indication information is TIM (Traffic Indication Map) information or DTIM (Delivery Traffic Indication Map) information in the beacon frame.

Specifically, when the indication information is TIM information, the access point may separately indicate, in time, buffered downlink data for a station supporting the OFDMA function and a station not supporting the OFDMA function, for example, TIM information in a beacon frame generated by the access point at a first time point is used to indicate to the multiple stations that the access point has buffered downlink data to be transmitted in the first time period, and TIM information in a beacon frame generated at a second time point is used to indicate to the station not supporting the OFDMA function that the access point has buffered downlink data to be transmitted in the second time period; when the indication information is DTIM information, the access point may indicate, through the DTIM information, to a plurality of stations supporting the OFDMA function that the access point has downlink data to be sent, which is cached in the access point, within a specified time.

In any one of the above technical solutions, preferably, the MU-RTS frame includes an information element, where the information element is used to indicate the number of buffered downlink data frames to be continuously sent to each group of stations. That is, the number of buffered downlink data frames to be continuously transmitted may be indicated to the station in the form of an Information Element (IE).

According to the second aspect of the present invention, there is also provided a communication method for a wireless local area network, including: receiving an MU-RTS frame sent by an access point, wherein the MU-RTS frame comprises resource block information distributed by the access point to each group of stations supporting an OFDMA function and the number of buffered downlink data frames to be continuously sent to each group of stations; feeding back a CTS frame to the access point based on the resource block information allocated in the MU-RTS frame; receiving a cached downlink data frame continuously sent by the access point; and replying an acknowledgement message frame aiming at the continuously received cached downlink data frames to the access point based on the resource block information distributed in the MU-RTS frame.

In the technical scheme, the MU-RTS frame generated by the access point includes resource block information allocated to each group of stations supporting the OFDMA function, so that the stations can feed back a CTS frame to the access point according to the resource block information, and the access point can continuously send the buffered downlink data frame to each group of stations by using the OFDMA technology (for example, by means of multicast). And the generated MU-RTS frame contains the number of the buffered downlink data frames to be continuously sent to each group of stations, so that the stations can determine the number of the buffered downlink data frames to be continuously received, and the buffered downlink data frames to be continuously sent by the access point can be conveniently received. Therefore, the technical scheme of the invention ensures that the OFDMA technology is reasonably applied in the continuous transmission process of the buffer downlink data frame by adopting the MU-RTS and CTS mechanism between the access point and the site supporting the OFDMA function, effectively improves the utilization efficiency of the frequency spectrum and meets the communication requirement of 802.11 ax.

According to the third aspect of the present invention, there is further provided a communication apparatus for a wireless local area network, including: a generating unit, configured to generate an MU-RTS frame, where the MU-RTS frame includes resource block information for feeding back a CTS frame, which is allocated to each group of stations that support an OFDMA function, and includes the number of buffered downlink data frames to be continuously sent to each group of stations; a first transmitting unit, configured to transmit the MU-RTS frame; a second sending unit, configured to continuously send the buffered downlink data frame to each station in any group of stations after receiving the CTS frame fed back by any group of stations.

Wherein, the resource block information includes: SS information, BW, and start frequency and end frequency assigned to each station. The resource block information is not only used for the station to receive the buffered downlink data frame, but also used for the station to reply a CTS frame and an acknowledgement message frame (such as M-BA) to the access point.

In the foregoing technical solution, preferably, the generating unit is further configured to generate a message frame, where the message frame includes indication information and grouping information, the indication information is used to indicate, to a plurality of stations supporting an OFDMA function, that a access point has downlink data to be sent, which is buffered, within a specified time, and the grouping information is used to indicate a grouping situation of the plurality of stations; the first transmitting unit is further configured to transmit the message frame prior to transmitting the MU-RTS frame.

In the foregoing technical solution, preferably, the message frame is a beacon frame, and the indication information is TIM information or DTIM information in the beacon frame.

In any one of the above technical solutions, preferably, the MU-RTS frame includes an information element, where the information element is used to indicate the number of buffered downlink data frames to be continuously sent to each group of stations. I.e. the number of buffered downlink data frames to be transmitted continuously can be indicated to the station in the form of an information element (i.e. IE).

According to the fourth aspect of the present invention, there is also provided a communication apparatus for a wireless local area network, including: a first receiving unit, configured to receive an MU-RTS frame sent by an access point, where the MU-RTS frame includes resource block information allocated by the access point to each group of stations supporting an OFDMA function, and includes the number of buffered downlink data frames to be continuously sent to each group of stations; a feedback unit, configured to feedback a CTS frame to the access point based on resource block information allocated in the MU-RTS frame; a second receiving unit, configured to receive buffered downlink data frames continuously sent by the access point; and the sending unit is used for replying the acknowledgement message frame aiming at the continuously received cached downlink data frame to the access point based on the resource block information distributed in the MU-RTS frame.

According to the fifth aspect of the present invention, there is also provided an access point, comprising: the communication device of the wireless local area network according to the third aspect.

According to a sixth aspect of the present invention, there is also provided a station, comprising: a communication apparatus of a wireless local area network as described in the fourth aspect above.

Through the technical scheme, the OFDMA technology is reasonably applied in the continuous transmission process of the cached downlink data frames, the utilization efficiency of the frequency spectrum is effectively improved, and the communication requirement of 802.11ax is met.

Drawings

Fig. 1 is a schematic diagram illustrating a buffered downlink data transmission between an AP and a station in the related art;

fig. 2 shows a schematic flow chart of a communication method of a wireless local area network according to a first embodiment of the present invention;

fig. 3 shows a schematic block diagram of a communication device of a wireless local area network according to a first embodiment of the present invention;

fig. 4 shows a schematic block diagram of an access point according to an embodiment of the invention;

fig. 5 shows a schematic flow chart of a communication method of a wireless local area network according to a second embodiment of the present invention;

fig. 6 shows a schematic block diagram of a communication device of a wireless local area network according to a second embodiment of the present invention;

FIG. 7 shows a schematic block diagram of a station according to an embodiment of the invention;

fig. 8 is a schematic diagram illustrating that an AP and a station perform buffered downlink data transmission according to an embodiment of the present invention.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

Fig. 2 shows a schematic flow chart of a communication method of a wireless local area network according to a first embodiment of the present invention.

As shown in fig. 2, a communication method of a wireless local area network according to a first embodiment of the present invention includes:

step S20, generating an MU-RTS frame, where the MU-RTS frame includes resource block information for feeding back a CTS frame, which is allocated to each group of stations supporting the OFDMA function, and includes the number of buffered downlink data frames to be continuously sent to each group of stations.

In one embodiment of the present invention, the number of buffered downlink data frames to be continuously transmitted may be indicated to the station in the form of an information element (i.e., IE).

The resource block information includes: SS information, BW, and start frequency and end frequency assigned to each station. The resource block information is not only used for the station to receive the buffered downlink data frame, but also used for the station to reply a CTS frame and an acknowledgement message frame (such as M-BA) to the access point.

And step S22, sending the MU-RTS frame.

The MU-RTS is sent during the CP, and the MU-RTS frame may also protect the communication process between the subsequent station and the AP, that is, protect the communication process in which the station receives the buffered downlink data and the station replies the acknowledgment message frame to the AP, and also protect the station to unicast the CTS frame sent to the access point.

Step S24, after receiving the CTS frame fed back by any group of stations, continuously sending the buffered downlink data frame to each station in any group of stations.

In an embodiment of the present invention, before step S22, the method further includes: generating a message frame, wherein the message frame comprises indication information and grouping information, the indication information is used for indicating that a plurality of sites supporting an OFDMA function have downlink data to be sent, which is cached by an access point, within a specified time, and the grouping information is used for indicating the grouping condition of the plurality of sites; and sending the message frame.

In the embodiment, the access point generates the message frame, and the indication information in the message frame can indicate that the access point has the cached downlink data to be sent in the specified time to the plurality of stations supporting the OFDMA function, so that for the plurality of stations supporting the OFDMA function, the access point can transmit the cached downlink data with the stations by using the OFDMA technology, thereby ensuring the application of the OFDMA technology in the transmission process of the cached downlink data and effectively improving the utilization efficiency of the frequency spectrum; and the message frame contains the grouping information, so that the access point can inform the station of the grouping condition after grouping a plurality of stations, and the access point can conveniently send the cached downlink data to the station in a multicast mode. Wherein the access point may group the plurality of stations supporting OFDMA functionality according to the number of the stations.

In an embodiment of the present invention, the message frame is a beacon frame, and the indication information is TIM information or DTIM information in the beacon frame. For example, when the AID (Association Identifier) corresponding to the TIM information is shown as 1, it indicates that the access point buffers the downlink data frame that needs to be sent to the corresponding station.

Among them, the execution subject of the communication method shown in fig. 2 may be a router or the like.

Fig. 3 shows a schematic block diagram of a communication device of a wireless local area network according to a first embodiment of the present invention.

As shown in fig. 3, a communication apparatus 300 of a wireless local area network according to a first embodiment of the present invention includes: a generating unit 302, a first transmitting unit 304 and a second transmitting unit 306.

The generating unit 302 is configured to generate an MU-RTS frame, where the MU-RTS frame includes resource block information for feeding back a CTS frame, which is allocated to each group of stations supporting an OFDMA function, and includes the number of buffered downlink data frames to be continuously sent to each group of stations; a first sending unit 304 is configured to send the MU-RTS frame; the second sending unit 306 is configured to continuously send the buffered downlink data frames to each station in any group of stations after receiving the CTS frame fed back by any group of stations.

In a specific implementation, the generating unit 302 may be a signal processor, a central processing unit, a baseband processor, or the like; the first transmission unit 304 and the second transmission unit 306 may be transmitters or antennas, etc.

In the foregoing technical solution, preferably, the generating unit 302 is further configured to generate a message frame, where the message frame includes indication information and grouping information, the indication information is used to indicate, to a plurality of stations supporting an OFDMA function, that a access point has downlink data to be sent, which is buffered, within a specified time, and the grouping information is used to indicate a grouping situation of the plurality of stations; the first transmitting unit is further configured to transmit the message frame prior to transmitting the MU-RTS frame.

Fig. 4 shows a schematic block diagram of an access point according to an embodiment of the invention.

As shown in fig. 4, an access point 400 according to an embodiment of the present invention includes: such as the communication device 300 of the wireless local area network shown in fig. 3.

Fig. 5 shows a schematic flow chart of a communication method of a wireless local area network according to a second embodiment of the present invention.

As shown in fig. 5, a communication method of a wireless local area network according to a second embodiment of the present invention includes:

step S50, receiving an MU-RTS frame sent by an access point, where the MU-RTS frame includes resource block information allocated by the access point to each group of stations supporting the OFDMA function, and includes the number of buffered downlink data frames to be continuously sent to each group of stations.

And step S52, feeding back a CTS frame to the access point based on the resource block information allocated in the MU-RTS frame.

Step S54, receiving buffered downlink data frames continuously sent by the access point.

Step S56, replying an acknowledgement message frame for the buffered downlink data frames received continuously to the access point based on the resource block information allocated in the MU-RTS frame.

The main body of the communication method shown in fig. 5 may be a mobile phone or a PDA (Personal Digital Assistant), or the like.

Fig. 6 shows a schematic block diagram of a communication device of a wireless local area network according to a second embodiment of the present invention.

As shown in fig. 6, a communication apparatus 600 of a wireless lan according to a second embodiment of the present invention includes: a first receiving unit 602, a feedback unit 604, a second receiving unit 606 and a transmitting unit 608.

The first receiving unit 602 is configured to receive an MU-RTS frame sent by an access point, where the MU-RTS frame includes resource block information allocated by the access point to each group of stations supporting an OFDMA function, and includes the number of buffered downlink data frames to be continuously sent to each group of stations; the feedback unit 604 is configured to feed back a CTS frame to the access point based on the resource block information allocated in the MU-RTS frame; the second receiving unit 606 is configured to receive buffered downlink data frames continuously sent by the access point; the sending unit 608 is configured to reply, to the access point, an acknowledgement message frame for the buffered downlink data frames that are continuously received, based on the resource block information allocated in the MU-RTS frame.

In a specific implementation, the first receiving unit 602 and the second receiving unit 606 may be receivers or antennas, and the feedback unit 604 and the sending unit 608 may be transmitters or antennas.

Fig. 7 shows a schematic block diagram of a station according to an embodiment of the invention.

As shown in fig. 7, a station 700 according to an embodiment of the present invention includes: such as communication device 600 of a wireless local area network shown in fig. 6.

In summary, the technical solution of the present invention is mainly to ensure that the access point can use the OFDMA technology to perform transmission of the buffered downlink data with the station supporting the OFDMA function, so as to improve the utilization efficiency of the frequency spectrum.

The method specifically comprises the following steps:

1. and buffering the broadcast of the downlink data.

During the CP, the AP broadcasts TIM/DTIM information in a beacon frame, and groups the stations that buffer downlink data and support OFDMA functions as needed, and broadcasts the grouped information in the beacon frame.

The TIM/DTIM message is used to indicate to a plurality of stations supporting the OFDMA function that the access point has buffered downlink data to transmit within a specified time. Specifically, when the indication information is TIM information, the access point may separately indicate, in time, buffered downlink data for a station supporting the OFDMA function and a station not supporting the OFDMA function, for example, TIM information in a beacon frame generated by the access point at a first time point is used to indicate to the multiple stations that the access point has buffered downlink data to be transmitted in the first time period, and TIM information in a beacon frame generated at a second time point is used to indicate to the station not supporting the OFDMA function that the access point has buffered downlink data to be transmitted in the second time period; when the indication information is DTIM information, the access point may indicate, through the DTIM information, to a plurality of stations supporting the OFDMA function that the access point has downlink data to be sent, which is cached in the access point, within a specified time.

2. And caching the receiving process of the downlink data.

As shown in fig. 8, the AP transmits an MU-RTS frame, the MU-RTS frame includes resource block information allocated by the AP, and stations (such as STA1, STA2, and STA3 shown in fig. 8) reply to the CTS frame according to the resource block information allocated by the access point after receiving the MU-RTS frame.

The AP may define a new sub-field in the MU-RTS and indicate to the station the number of data frames to be continuously transmitted to the station through the new sub-field, for example, may define a new information element to indicate the number of buffered downlink data frames to be continuously transmitted to the station.

After receiving the CTS frame replied by the station, the AP continuously sends the buffered downlink data frame to the station, and then the station replies an acknowledgment message frame (i.e., Multi Block ACK, M-BA for short, Multi-user acknowledgment message frame) to the AP through the resource Block information allocated by the access point.

When feeding back the CTS frame and the ACK frame to the AP, the station may feed back to the AP at the same time or at different times. The resource block information includes: SS information, BW, etc.

The technical scheme of the invention is described in detail in the above with reference to the accompanying drawings, and the invention provides a new communication scheme of a wireless local area network, so that the OFDMA technology is guaranteed to be reasonably applied in the continuous transmission process of the buffered downlink data frames, the utilization efficiency of the frequency spectrum is effectively improved, and the communication requirement of 802.11ax is met.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A communication method for a wireless local area network, comprising:

generating an MU-RTS frame, wherein the MU-RTS frame comprises resource block information which is distributed to each group of stations supporting the OFDMA function and is used for feeding back a CTS frame, and the MU-RTS frame comprises the number of buffered downlink data frames which are to be continuously sent to each group of stations;

transmitting the MU-RTS frame;

after receiving the CTS frame fed back by any group of stations, continuously sending the cached downlink data frame to each station in any group of stations;

before the step of sending the MU-RTS frame, the method further comprises:

generating a message frame, wherein the message frame comprises indication information and grouping information, the indication information is used for indicating that a plurality of stations supporting the OFDMA function have downlink data to be sent, and the grouping information is used for indicating the grouping condition of the plurality of stations, and the stations are grouped by the access point according to the number of the plurality of stations supporting the OFDMA function;

and sending the message frame.

2. The communication method according to claim 1, wherein the message frame is a beacon frame, and the indication information is TIM information or DTIM information in the beacon frame.

3. A communication method of a wireless local area network according to claim 1 or 2, wherein the MU-RTS frame includes an information element, and the information element is used to indicate the number of buffered downlink data frames to be sent to each group of stations consecutively.

4. A communication method for a wireless local area network, comprising:

receiving an MU-RTS frame sent by an access point, wherein the MU-RTS frame comprises resource block information distributed by the access point to each group of stations supporting an OFDMA function and the number of buffered downlink data frames to be continuously sent to each group of stations;

feeding back a CTS frame to the access point based on the resource block information allocated in the MU-RTS frame;

receiving a cached downlink data frame continuously sent by the access point;

replying a confirmation message frame aiming at the continuously received cached downlink data frames to the access point based on the resource block information distributed in the MU-RTS frame;

before the step of receiving the MU-RTS frame, further comprising:

receiving a message frame, wherein the message frame comprises indication information and grouping information, the indication information is used for indicating that a plurality of stations supporting the OFDMA function have downlink data to be sent, and the grouping information is used for indicating the grouping condition of the plurality of stations, and the access point groups the plurality of stations supporting the OFDMA function according to the number of the stations.

5. A communication apparatus of a wireless local area network, comprising:

a generating unit, configured to generate an MU-RTS frame, where the MU-RTS frame includes resource block information for feeding back a CTS frame, which is allocated to each group of stations that support an OFDMA function, and includes the number of buffered downlink data frames to be continuously sent to each group of stations;

a first transmitting unit, configured to transmit the MU-RTS frame;

a second sending unit, configured to continuously send the buffered downlink data frame to each station in any group of stations after receiving a CTS frame fed back by any group of stations;

the generating unit is further configured to generate a message frame, where the message frame includes indication information and grouping information, the indication information is used to indicate, to a plurality of stations supporting the OFDMA function, that the access point has downlink data to be sent, which is cached in a specified time, and the grouping information is used to indicate a grouping situation of the plurality of stations, where the access point groups the plurality of stations supporting the OFDMA function according to the number of the stations;

the first transmitting unit is further configured to transmit the message frame prior to transmitting the MU-RTS frame.

6. The apparatus according to claim 5, wherein the message frame is a beacon frame, and the indication information is TIM information or DTIM information in the beacon frame.

7. A communication apparatus of a wireless local area network according to claim 5 or 6, wherein the MU-RTS frame includes an information element indicating the number of buffered downlink data frames to be consecutively transmitted to each group of stations.

8. A communication apparatus of a wireless local area network, comprising:

a first receiving unit, configured to receive an MU-RTS frame sent by an access point, where the MU-RTS frame includes resource block information allocated by the access point to each group of stations supporting an OFDMA function, and includes the number of buffered downlink data frames to be continuously sent to each group of stations;

a feedback unit, configured to feedback a CTS frame to the access point based on resource block information allocated in the MU-RTS frame;

a second receiving unit, configured to receive buffered downlink data frames continuously sent by the access point;

a sending unit, configured to reply, to the access point, a confirmation message frame for a continuously received buffered downlink data frame based on the resource block information allocated in the MU-RTS frame;

the first receiving unit is further configured to receive a message frame before receiving the MU-RTS frame, where the message frame includes indication information and grouping information, the indication information is used to indicate, to a plurality of stations supporting an OFDMA function, that an access point has downlink data to be sent, which is buffered in a specified time, and the grouping information is used to indicate a grouping situation of the plurality of stations, where the access point groups the plurality of stations supporting the OFDMA function according to the number of the plurality of stations.

9. An access point, comprising: communication device of a wireless local area network according to any of claims 5 to 7.

10. A station, comprising: communication device of a wireless local area network according to claim 8.