Direct link protocol in wireless local area networks

• US 6,791,962 B2
• Filed: 01/29/2003
• Issued: 09/14/2004
• Est. Priority Date: 06/12/2002
• Status: Active Grant

• Current Assignee: Intellectual Ventures I LLC (Intellectual Ventures LLC)
• Original Assignee: Globespan Virata, Inc.
• Inventors: Wentink, Maarten Menzo
• Primary Examiner(s): Duong, Frank
• Application Number:
  US10/353,391
• Publication Number:
  US 20030231608A1
• Time in Patent Office: 594 Days
• Field of Search: 370/310, 370/328, 370/336, 370/337, 370/338, 370/345, 370/346, 370/347, 370/348, 370/311, 370/445, 370/449, 370/461, 370/462, 709/238, 709/242, 340/825.72
• US Class Current: 370/338
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 92/18 between terminal devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A technique enabling enhanced stations to communicate with other enhanced stations that periodically or sporadically enter power save mode is disclosed. If a Q-station targeted for a direct link is in power save mode, an access point “wakes” the Q-station. The targeted Q-station responds by transmitting back a PS-Poll frame. The access point then forwards an awaiting direct_link_protocol_request frame to the targeted Q-station, which then responds by transmitting back a direct_link_protocol_response frame to the transmitting Q-station. Subsequently, the targeted Q-station can expect to receive a frame directly from a Q-station requesting the direct link. For example, a data frame containing data or a direct_link_protocol_probe frame can be transmitted. In this way, Q-stations do not have to track when other Q-stations are in power save mode.

Claims

1. A method comprising:

receiving at an access point from a first Q-station a direct_link_protocol_request frame that indicates a second Q-station as the destination of said direct_link_protocol_request frame;

transmitting from said access point a traffic indication map that indicates that traffic is available for said second Q-station;

receiving at said access point, in response to the transmission of said traffic indication map, a PS-Poll frame from said second Q-station; and

forwarding from said access point, in response to the reception of said PS-Poll frame, said direct_link_protocol_request frame to said second Q-station.

2. The method of claim 1 further comprising:

receiving at said access point from said second Q-station, in response to forwarding said direct_link_protocol_request frame, a direct_link_protocol_response frame that indicates said first Q-station as the destination of said response frame; and

forwarding from said access point, in response to said direct_link_protocol_response frame, said direct_link_protocol_response frame to said first Q-station.

3. The method of claim 1 wherein said direct_link_protocol_request frame comprises a destination medium access control address, a source medium access control address, capability information of said first Q-station, supported rates information of said first Q-station, and extended capabilities information of said first Q-station.

4. The method of claim 1 wherein said direct_link_protocol_response frame comprises a destination medium access control address, a source medium access control address, capability information of said second Q-station, supported rates information of said second Q-station, and extended capabilities information of said second Q-station.

5. A system comprising:

(1) a first station for;

(a) transmitting, in response to receiving a direct_link_protocol_response frame, at least one data frame directly to a second station;

(2) an access point for;

(a) queuing a direct_link_protocol_request frame;

(b) transmitting a traffic indication map that indicates that traffic is available for said second station;

(c) forwarding, in response to receiving a PS-Poll frame from said second station, said direct_link_protocol_request frame to said second station for the purpose of establishing a direct link between said first station and said second station; and

(d) forwarding, in response to receiving said direct_link_protocol_response frame from said second station, said direct_link_protocol_response frame to said first station; and

(3) said second station for;

(a) transmitting, in response to receiving said traffic indication map, said PS-Poll frame to said access point; and

(b) transmitting, in response to receiving said direct_link_protocol_request frame from said access point, said direct_link_protocol_response frame to said access point.

6. The system of claim 5 wherein said first station also transmits, in response to receiving said direct_link_protocol_response frame, a direct_link_protocol_probe frame directly to said second station.

7. The system of claim 5 wherein said second station also transmits, subsequent to transmitting said direct_link_protocol_response frame, a direct_link_protocol_probe frame directly to said first station.

8. The system of claim 5 wherein said first station initiates said direct link with said second station by transmitting said direct_link_protocol_request frame to said access point.

9. The system of claim 5 wherein said first station and said second station are quality-of-service enhanced.

10. The system of claim 5 wherein said first station and said second station remain active for the duration of said direct link.

11. The system of claim 5 wherein said access point attaches said first station and said second station to a wired backbone network.

12. A method comprising:

receiving at said first Q-station from an access point a traffic indication map that indicates that traffic is available for said first Q-station;

transmitting from said first Q-station, in response to receiving said traffic indication map, a PS-Poll frame to said access point; and

receiving at said first Q-station from said access point, in response to transmitting said PS-Poll frame, a direct_link_protocol_request frame that indicates a second Q-station as the source.

13. The method of claim 12 further comprising:

transmitting from said first Q-station to said access point, in response to receiving said direct_link_protocol_request frame, a direct_link_protocol_response frame that indicates said second Q-station as the destination of said response frame; and

receiving at said first Q-station directly from said second Q-station, in response to transmitting said direct_link_protocol_response frame, at least one data frame.

14. The method of claim 13 wherein said first Q-station remains ready to communicate directly with said second Q-station for at least the duration of about aDLPIdleTimeout after said first Q-station transmits said direct_link_protocol_response frame.

15. The method of claim 13 wherein said direct_link_protocol_request frame and said direct_link_protocol_response frame comprise security information.

16. The method of claim 13 further comprising receiving at said first Q-station directly from said second Q-station a direct_link_protocol_probe frame.

17. The method of claim 16 wherein said direct_link_protocol_probe frame comprises a destination medium access control address, a source medium access control address, and random data.

18. The method of claim 12 further comprising transmitting from said first Q-station to said access point, in response to receiving said direct_link_protocol_request frame, a direct_link_protocol_response frame that indicates said second Q-station as the destination of said response frame and that the first Q-station is not willing to participate in direct link communication with said second Q-station.

19. The method of claim 12 further comprising:

transmitting from said first Q-station directly to said second Q-station, in response to receiving said direct_link_protocol_request frame, a direct_link_protocol_response frame that indicates said second Q-station as the destination of said response frame; and

receiving at said first Q-station directly from said second Q-station, in response to transmitting said direct_link_protocol_response frame, at least one data frame.

20. A first station comprising:

(1) a receiver for;

(a) receiving a traffic indication map; and

(b) receiving a direct_link_protocol_request frame; and

(2) a transmitter for;

(a) transmitting, in response to receiving said traffic indication map, a PS-Poll frame; and

(b) transmitting, in response to receiving said direct_link_protocol_request frame, a direct_link_protocol_response frame.

21. The first station of claim 20 wherein said first station also receives a direct_link_protocol_probe frame directly from a second station.

22. The first station of claim 20 wherein said first station remains active for the duration of said direct link wherein the duration starts when said first station transmits said direct_link_protocol_response frame.

23. The first station of claim 20 wherein said first station is quality-of-service enhanced.