# US 7,609,648 B2 · Antenna steering for an access point based upon control frames > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,648 B2 - Document ID: US7609648B2 - Status: Granted - Kind: B2 - Application number: 10/870,718 - Filed: 2004-06-17 - Published: 2005-03-24 - Granted: 2009-10-27 - Earliest claimed: 2003-06-19 - Assignees: IPR Licensing, Inc. - Inventors: John E. Hoffmann; Kevin P. Johnson; George Rodney Nelson, Jr.; John A. Regnier - Web page: https://patentgrep.com/patent/US7609648B2 ## CPC - H04B 7/0602: {using antenna switching (H04B7/0686 takes precedence; antenna beam directivity switching H01Q3/24)} - H04B 7/0408: using two or more beams, i.e. beam diversity - H04B 7/0608: {Antenna selection according to transmission parameters} - H04W 88/08: Access point devices - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## 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 ### Claim 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 1) 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. ### Claim 4 (depends on 3) 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. ### Claim 5 (depends on 1) A method according to claim 1 wherein the first antenna pattern comprises an omni angle, and the second antenna pattern comprises a directional angle. ### Claim 6 (depends on 1) 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. ### Claim 7 (depends on 1) 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. ### Claim 8 (depends on 1) 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. ### Claim 9 (depends on 1) 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. ### Claim 10 (depends on 1) 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. ### Claim 11 (depends on 1) 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. ### Claim 12 (depends on 1) A method according to claim 1 wherein the directional antenna comprises at least one active element and a plurality of passive elements. ### Claim 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. ### Claim 14 (depends on 13) 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. ### Claim 15 (depends on 13) A method according to claim 13 wherein the first antenna pattern comprise an omni angle, and the second antenna pattern comprises a directional angle. ### Claim 16 (depends on 13) 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. ### Claim 17 (depends on 13) 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. ### Claim 18 (depends on 13) 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. ### Claim 19 (depends on 13) A method according to claim 13 wherein the directional antenna comprises at least one active element and a plurality of passive elements. ### Claim 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. ### Claim 21 (depends on 20) An access point according to claim 20 wherein said directional antenna comprises at least one active element and a plurality of passive elements. ### Claim 22 (depends on 20) 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. ### Claim 23 (depends on 20) 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. ### Claim 24 (depends on 23) 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. ### Claim 25 (depends on 20) 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. ### Claim 26 (depends on 20) 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. ### Claim 27 (depends on 20) 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. ### Claim 28 (depends on 20) 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. ### Claim 29 (depends on 20) 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. ### Claim 30 (depends on 20) 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. ### Claim 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. ### Claim 32 (depends on 31) An access point according to claim 31 wherein said directional antenna comprises at least one active element and a plurality of passive elements. ### Claim 33 (depends on 31) 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. ### Claim 34 (depends on 31) 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. ### Claim 35 (depends on 31) 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. ### Claim 36 (depends on 31) 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.