Antenna steering for an access point based upon control frames

• US 7,609,648 B2
• Filed: 06/17/2004
• Issued: 10/27/2009
• Est. Priority Date: 06/19/2003
• Status: Expired due to Fees

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Inventors: Hoffmann, John E., Johnson, Kevin P., Nelson, George Rodney Jr., Regnier, John A.
• Primary Examiner(s): Jagannathan; Melanie
• Application Number:
  US10/870,718
• Publication Number:
  US 20050063343A1
• Time in Patent Office: 1,958 Days
• Field of Search: 370/277, 370/278, 370/310, 370/339, 370/338, 370/334, 455/562.1, 455133-139, 342/74, 342/75, 342/77, 343/853, 375/267, 375/347
• US Class Current: 370/252
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0602 using antenna switching H04B7/0686 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/0608 Antenna selection according to transmission parameters
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A method for operating an access point in a wireless local area network (WLAN) is provided. The access point includes a directional antenna for communicating with at least one remote station in a forward link based upon an exchange of packet data comprising a plurality of control frames and a data frame. The directional antenna includes a plurality of antenna patterns. The method includes receiving a first control frame via a first antenna pattern of the directional antenna from the remote station, transmitting a first data frame to the remote station, and receiving a second control frame via a second antenna pattern of the directional antenna from the remote station. A signal quality of the first control frame received via the first antenna pattern and a signal quality of the second control frame received via the second antenna pattern are measured. The respective measured signal qualities associated with the first and second antenna patterns are compared.

Claims

1. A method for operating an access point in a wireless local area network (WLAN), the access point comprising a directional antenna for communicating in a forward link with at least one remote station based upon an exchange of packet data comprising a plurality of control frames and a data frame, the directional antenna comprising a plurality of antenna patterns, the method comprising:

receiving at the access point in the forward link with the at least one remote station a first control frame via a first antenna pattern of the directional antenna from the at least one remote station;

transmitting at the access point a first data frame to the at least one remote station;

receiving at the access point a second control frame via a second antenna pattern of the directional antenna from the at least one remote station;

measuring at the access point a signal quality of the first control frame received via the first antenna pattern and a signal quality of the second control frame received via the second antenna pattern;

comparing at the access point the respective measured signal qualities associated with the first and second antenna patterns; and

selecting at the access point the first or second antenna pattern of the directional antenna based on the comparing.

2. A method according to claim 1 wherein the second antenna pattern is selected for transmitting a second data frame to the at least one remote station if the measured signal quality associated with the second antenna pattern exceeds the measured signal quality associated with the first antenna pattern by a predetermined threshold.

3. A method according to claim 1 wherein transmitting the first data frame is performed using a preferred antenna pattern of the directional antenna;

and wherein the comparing further comprises comparing the respective measured signal qualities associated with the first and second antenna patterns with a signal quality associated with the preferred antenna pattern.

4. A method according to claim 3 wherein the second antenna pattern is selected for transmitting a second data frame to the at least one remote station if the measured signal quality associated with the second antenna pattern exceeds the measured signal qualities associated with the first and preferred antenna patterns by a predetermined threshold.

5. A method according to claim 1 wherein the first antenna pattern comprises an omni angle, and the second antenna pattern comprises a directional angle.

6. A method according to claim 1 wherein the first antenna pattern comprises a first directional angle, and the second antenna pattern comprises a second directional angle.

7. A method according to claim 1 wherein the first control frame received comprises a clear-to-send message, and the second control frame received comprises an acknowledgement message.

8. A method according to claim 1 further comprising creating an antenna database including the respective measured signal qualities associated with the first and second antenna patterns.

9. A method according to claim 1 further comprising selecting the first antenna pattern and the second antenna pattern, and wherein the selecting are performed at the media access control (MAC) layer of the access point.

10. A method according to claim 1 wherein measuring the respective signal qualities comprises determining at least one of a received signal strength indication, a carrier to interference ratio, an energy per bit ratio and a signal to noise ratio.

11. A method according to claim 1 wherein the access point is operating based upon at least one of an IEEE 802.11 standard and an IEEE 802.16 standard.

12. A method according to claim 1 wherein the directional antenna comprises at least one active element and a plurality of passive elements.

13. A method for operating an access point in a wireless local area network (WLAN), the access point comprising a directional antenna for communicating with at least one remote station in a reverse link based upon an exchange of packet data comprising a plurality of control frames and a data frame, the directional antenna comprising a plurality of antenna patterns, the method comprising:

receiving at the access point in the reverse link with the at least one remote station a first control frame via a first antenna pattern of the directional antenna from the at least one remote station;

transmitting at the access point a second control frame to the at least one remote station;

receiving at the access point a first data frame via a second antenna pattern of the directional antenna from the at least one remote station;

measuring at the access point a signal quality of the first control frame received via the first antenna pattern and a signal quality of the first data frame received via the second antenna pattern;

comparing at the access point the respective measured signal qualities associated with the first and second antenna patterns; and

selecting at the access point the first or second antenna pattern of the directional antenna based on the comparing.

14. A method according to claim 13 wherein the second antenna pattern is selected for transmitting a second data frame by the access point to the at least one remote station if the measured signal quality associated with the second antenna pattern exceeds the measured signal quality associated with the first antenna pattern by a predetermined threshold.

15. A method according to claim 13 wherein the first antenna pattern comprise an omni angle, and the second antenna pattern comprises a directional angle.

16. A method according to claim 13 wherein the first antenna pattern comprises a first directional angle, and the second antenna pattern comprises a second directional angle.

17. A method according to claim 13 wherein the first control frame received comprises a request-to-send message, and the second control frame transmitted comprises a clear-to-send message.

18. A method according to claim 13 further comprising creating an antenna database including the respective measured signal qualities associated with the first and second antenna patterns.

19. A method according to claim 13 wherein the directional antenna comprises at least one active element and a plurality of passive elements.

20. An access point for a wireless local area network (WIJAN) comprising:

a directional antenna comprising a plurality of antenna patterns; and

a controller connected to said directional antenna for control thereof, said controller communicating with at least one remote station in a forward link based upon an exchange of packet data comprising a plurality of control frames and a data frame, said controller

receiving a first control frame via a first antenna pattern of said directional antenna from the at least one remote station,

transmitting a first data frame to the at least one remote station,

receiving a second control frame via a second antenna pattern of said directional antenna from the at least one remote station,

measuring a signal quality of the first control frame received via the first antenna pattern and a signal quality of the second control frame received via the second antenna pattern,

comparing the respective measured signal qualities associated with the first and second antenna patterns, and

selecting the first or second antenna pattern of said directional antenna based on the comparing.

21. An access point according to claim 20 wherein said directional antenna comprises at least one active element and a plurality of passive elements.

22. An access point according to claim 20 wherein said controller selects the second antenna pattern for transmitting a next data frame to the at least one remote station if the measured signal quality associated with the second antenna pattern exceeds the measured signal quality associated with the first antenna pattern by a predetermined threshold.

23. An access point according to claim 20 wherein transmitting the data frame is performed by said controller using a preferred antenna pattern of said directional antenna;

and wherein the comparing by said controller further comprises comparing the respective measured signal qualities associated with the first and second antenna patterns with a signal quality associated with the preferred antenna pattern.

24. An access point according to claim 23 wherein said controller selects the second antenna pattern for transmitting a second data frame to the at least one remote station if the measured signal quality associated with the second antenna pattern exceeds the measured signal qualities associated with the first and preferred antenna patterns by a predetermined threshold.

25. An access point according to claim 20 wherein the first antenna pattern comprise an omni angle, and the second antenna pattern comprises a directional angle.

26. An access point according to claim 20 wherein the first antenna pattern comprises a first directional angle, and the second antenna pattern comprises a second directional angle.

27. An access point according to claim 20 wherein the first control frame received comprises a clear-to-send message, and the second control frame transmitted comprises an acknowledgement message.

28. An access point according to claim 20 wherein said controller creates an antenna database including the respective measured signal qualities associated with the first and second antenna patterns, and stores the antenna database.

29. An access point according to claim 20 wherein said controller comprises a physical layer and a media access control (MAC), and selection of the first antenna pattern and the second antenna pattern are performed at the MAC layer.

30. An access point according to claim 20 wherein said controller measures the respective signal qualities based upon determining at least one of a received signal strength indication, a carrier-to-interference ratio, an energy-per-bit ratio and a signal-to-noise ratio.

31. An access point for a wireless local area network (WLAN) comprising:

a directional antenna comprising a plurality of antenna patterns; and

a controller connected to said directional antenna for control thereof, said controller communicating with at least one remote station in a reverse link based upon an exchange of packet data comprising a plurality of control frames and a data frame, said controller

receiving a first control frame via a first antenna pattern of said directional antenna from the at least one remote station,

transmitting a second control frame to the at least one remote station,

receiving a first data frame via a second antenna pattern of said directional antenna from the at least one remote station,

measuring a signal quality of the first control frame received via the first antenna pattern and a signal quality of the first data frame received via the second antenna pattern,

comparing the respective measured signal qualities associated with the first and second antenna patterns, and

selecting the first or second antenna pattern of the directional antenna based on the comparing.

32. An access point according to claim 31 wherein said directional antenna comprises at least one active element and a plurality of passive elements.

33. An access point according to claim 31 wherein said controller selects the second antenna pattern for transmitting a second data frame to the at least one remote station if the measured signal quality associated with the second antenna pattern exceeds the measured signal quality associated with the first antenna pattern by a predetermined threshold.

34. An access point according to claim 31 wherein the first antenna pattern comprise an omni angle, and the second antenna pattern comprises a directional angle.

35. An access point according to claim 31 wherein the first antenna pattern comprises a first directional angle, and the second antenna pattern comprises a second directional angle.

36. An access point according to claim 31 wherein the first control frame received comprises a request-to-send message, and the second control frame transmitted comprises a clear-to-send message.