Method, device and system for device to device D2D data transmission

1. A method for device to device (D2D) data transmission, wherein the method comprises:

monitoring, by a first station, a beacon frame broadcast by an access point (AP), and detecting whether the beacon frame has a buffer information indication of a second station, wherein the first station is in a sleep state, and the buffer information indication is used to indicate that the second station has buffered data to be transmitted to the first station;

transmitting, by the first station, a response frame to the second station when it is determined that the beacon frame has the buffer information indication; and

receiving, by the first station, the buffered data transmitted by the second station.

2. The method according to claim 1 , wherein, when there are M first stations, the beacon frame has M element fields, wherein buffer information indications carried in the M element fields are one-to-one corresponding to the M first stations, and M is an integer which is equal to or greater than 2.

3. The method according to claim 1 , wherein the buffer information indication comprises an element ID, an element length and an element body, wherein:

the element ID is used to indicate that the beacon frame comprises a buffer information indication field;

the element length is used to indicate a length of the buffer information indication field; and

the element body comprises identification information identifying the first station and the second station, wherein the identification information is used to set up a direct link between the first station and the second station.

4. The method according to claim 3 , wherein the identification information is a media access control (MAC) address of the first station and a MAC address of the second station.

5. The method according to claim 3 , wherein the indication information is a link identifier, the link identifier is a preset unique link identifier, and the preset unique link identifier is a unique D2D account in a basic service set assigned by the AP during setup of each D2D link, which is used to identify the D2D link that is set up.

6. The method according to claim 3 , wherein the identification information is a link identifier, the link identifier is a D2D ID bitmap, and the D2D ID bitmap is a multi-bit sequence, wherein each bit in the multi-bit sequence indicates a D2D link.

7. The method according to claim 1 , further comprising:

receiving, by the AP, a buffered data indication frame transmitted by the second station, wherein the indication frame is used to indicate that the second station has the buffered data to be transmitted to the first station; and

extracting, by the AP, a buffer information indication in the buffered data indication frame.

8. The method according to claim 7 , wherein the buffered data indication frame comprises a frame type, an Action, a dialog Token and a link identifier, wherein the frame type is used to indicate that a type of the data frame is the buffered data indication frame; the Action is used to indicate that an action corresponding to the data frame indicates that there is buffered data to be transmitted to a corresponding D2D sleeping station; the dialog Token identifies a dialog process of the data frame; and the link identifier is used to indicate a direct link set up between the first station and the second station.

9. A device to device (D2D) terminal device that serves as a first station to set up a direct link with a second station in a sleep state, the D2D terminal device comprising:

a monitoring unit, configured to monitor a beacon frame broadcast by an access point (AP), and to detect whether the beacon frame has a buffer information indication of the second station, wherein the buffer information indication is used to indicate that the second station has buffered data needing to be transmitted to the first station;

a responding unit, configured to transmit a response frame from the first station to the second station when it is determined that the beacon frame has the buffer information indication; and

a receiving unit, configured to receive the buffered data transmitted by the second station.

10. The D2D terminal device according to claim 9 , wherein, when there are M first stations, the monitoring unit is further configured to monitor M element fields in the beacon frame, wherein buffer information indications of D2D links carried in the M element fields are one-to-one corresponding to the M first stations, and M is an integer which is equal to or greater than 2.

11. The D2D terminal device according to claim 9 , wherein the monitoring unit is further configured to detect an element ID, an element length and an element body comprised in the buffer information indication to determine whether the beacon frame has a first buffer information indication of the second station, wherein the element ID is used to indicate that the beacon frame comprises a buffer information indication field; the element length is used to indicate a length of the buffer information indication field; and the element body comprises identification information identifying the first station and the second station, and the identification information is used to set up a direct link between the first station and the second station.

12. The D2D terminal device according to claim 11 , wherein the responding unit is further configured to determine a D2D direct link between the first station and the second station according to a media access control (MAC) address of the first station and a MAC address of the second station identified by the identification information.

13. The D2D terminal device according to claim 11 , wherein the indication information is a link identifier, and the responding unit is further configured to determine a D2D direct link between the first station and the second station according to the link identifier, wherein the link identifier is a preset unique link identifier, and the preset unique link identifier is a unique D2D account in a basic service set assigned by the AP during setup of each D2D link, which is used to identify the D2D link that is set up.

14. The D2D terminal device according to claim 11 , wherein the indication information is a link identifier, and the responding unit is further configured to determine a D2D direct link between the first station and the second station according to the link identifier, wherein the link identifier is a D2D ID bitmap, and the D2D ID bitmap is a multi-bit sequence, wherein each bit in the multi-bit sequence indicates a D2D link.