Method for operating a smart antenna in a WLAN using medium access control information

• US 7,428,408 B2
• Filed: 09/16/2005
• Issued: 09/23/2008
• Est. Priority Date: 09/20/2004
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Cha, Inhyok, Li, Yingxue
• Primary Examiner(s): NGUYEN, THUAN T
• Application Number:
  US11/228,816
• Publication Number:
  US 20060079220A1
• Time in Patent Office: 1,103 Days
• Field of Search: 455/275.1, 455/277.1, 455/277.2, 455/452.1, 455/452.3, 455/13.3, 455 8- 10, 455/41.2, 455/41.1, 455/276.1, 455/67.11, 455/67.13, 343/702, 343/833, 343/834
• US Class Current: 455/276.1
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04B 7/082 selecting best antenna path
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A communications device with a switched beam antenna operates in a wireless local area network (WLAN) that includes a plurality of transmitters. The switched beam antenna generates a plurality of antenna beams. A method for operating the communications device includes receiving signals from the plurality of transmitters operating within the WLAN, identifying the received signals comprising medium access control (MAC) information, and determining a quality metric for each received signal comprising MAC information. A transmitter is selected based on the quality metrics. The antenna beams are scanned for receiving from the selected transmitter the signals comprising MAC information. A quality metric associated with each scanned antenna beam is determined. One of the scanned antenna beams is then selected for communicating with the selected transmitter based on the quality metrics.

Claims

1. A method for operating a communications device in a wireless local area network (WLAN) comprising a plurality of transmitters, the communications device comprising a switched beam antenna for generating a plurality of antenna beams, the method comprising:

receiving signals from the plurality of transmitters operating within the WLAN;

identifying the received signals comprising medium access control (MAC) information;

determining a quality metric for each received signal comprising MAC information;

selecting a transmitter based on the quality metrics;

scanning the plurality of antenna beams for receiving from the selected transmitter the signals comprising MAC information, and determining a quality metric associated with each scanned antenna beam; and

selecting one of the scanned antenna beams for communicating with the selected transmitter based on the quality metrics.

2. A method according to claim 1 wherein the MAC information is included within a packet, the MAC information comprising for each packet a source address and a destination address.

3. A method according to claim 2 further comprising associating the selected antenna beam with the source address of the selected transmitter so that when a subsequent packet is received with the same source address, the same antenna beam is used to receive the MAC information.

4. A method according to claim 1 further comprising:

periodically scanning the plurality of antenna beams for receiving from the non-selected transmitters the signals comprising MAC information, and determining a quality metric associated with each scanned antenna beam;

comparing the quality metrics associated with the non-selected transmitters to the quality metric associated with the selected transmitter; and

selecting one of the scanned antenna beams based on the comparing for communicating with one of the non-selected transmitters.

5. A method according to claim 1 further comprising:

identifying the transmitters not providing signals comprising MAC information; and

avoiding selection of antenna beams in a direction of the identified transmitters not providing signals comprising MAC information.

6. A method according to claim 1 wherein determining the quality metric for each received signal is based on the MAC information associated therewith, the MAC information comprising at least one of a received signal strength indicator (RSSI) value, a received packet RATE value indicating a transmission rate by which the signal was transmitted, a LENGTH value indicating a number of bytes contained in a data part of the signal, and a value of a dot11 counter.

7. A method according to claim 1 wherein determining the quality metric for each received signal is based on the MAC information associated therewith, the MAC information comprising at least one of a received packet-error rate, a packet success rate, an average PHY transmission rate of received frames, and an average short-term throughput of a data part of the signal.

8. A method according to claim 1 wherein the plurality of antenna beams comprises a plurality of directional antenna beams.

9. A method according to claim 1 wherein the plurality of antenna beams comprises a plurality of directional antenna beams and an omni-directional antenna beam, with the omni-directional beam being used for identifying the received signals comprising MAC information, and a directional antenna beam being used for communicating with the selected transmitter.

10. A communications device for operating in a wireless local area network (WLAN) comprising a plurality of transmitters, the communications device comprising:

a switched beam antenna for generating a plurality of antenna beams;

a beam selector connected to said switched beam antenna for selecting one of said plurality of antenna beams;

a transceiver connected to said switched beam antenna and to said beam selector for receiving signals from the plurality of transmitters operating within the WLAN, said transceiver comprising

a medium access control (MAC) module for identifying the received signals comprising MAC information, and

a quality metric module for determining a quality metric for each received signal comprising MAC information;

said beam selector for selecting a transmitter based on the quality metrics, and for scanning the plurality of antenna beams for receiving from the selected transmitter the signals comprising MAC information;

said quality metric module for determining a quality metric associated with each scanned antenna beam; and

said beam selector for selecting one of the scanned antenna beams for communicating with the selected transmitter based on the quality metrics.

11. A communications device according to claim 10 wherein the MAC information is included within a packet, the MAC information comprising for each packet a source address and a destination address.

12. A communications device according to claim 11 wherein said transceiver associates the selected antenna beam with the source address of the selected transmitter so that when a subsequent packet is received with the same source address, the same antenna beam is used to receive the MAC information.

13. A communications device according to claim 10 wherein said beam selector periodically scans the plurality of antenna beams for receiving from the non-selected transmitters the signals comprising MAC information;

wherein said quality metric module determines a quality metric associated with each scanned antenna beam, and compares the quality metrics associated with the non-selected transmitters to the quality metric associated with the selected transmitter; and

wherein said beam selector selects one of the scanned antenna beams based on the comparing for communicating with one of the non-selected transmitters.

14. A communications device according to claim 10 wherein said MAC module identifies the transmitters not providing signals comprising MAC information;

and wherein said beam selector avoids selection of antenna beams in a direction of the identified transmitters not providing signals comprising MAC information.

15. A communications device according to claim 10 wherein said transceiver further comprises:

a signal strength indicator (RSSI) module for determining a received signal strength for each received signal;

a RATE module for determining a received packet RATE value indicating a transmission rate by which each signal was transmitted;

a LENGTH module for determining a LENGTH value indicating a number of bytes contained in a data part of each signal;

a counter for counting a received number of packets for each signal; and

wherein said quality metric module determines the quality metric for each received signal based on the MAC information associated therewith, the MAC information comprising at least one of the received RSSI value from said RSSI module, the received packet RATE value from said RATE module, the LENGTH value from said LENGTH module, and the value of said counter.

16. A communications device according to claim 10 wherein said transceiver further comprises:

a received packet-error rate module for determining an error rate of received packets for each signal;

a packet success rate module for determining a success rate of received packets for each signal;

a transmission rate module for determining an average PHY transmission rate of received frames for each signal;

a throughput module for determining an average short-term throughput of a data part for each signal;

wherein said quality metric module determines the quality metric for each received signal based on the MAC information associated therewith, the MAC information comprising at least one of the received packet-error rate, the packet success rate, the average PHY transmission rate of the received frames for each signal, and the average short-term throughput of a data part for each signal.

17. A communications device according to claim 10 wherein the plurality of antenna beams comprises a plurality of directional antenna beams.

18. A communications device according to claim 10 wherein the plurality of antenna beams comprises a plurality of directional antenna beams and an omni-directional antenna beam, with the omni-directional beam being used for identifying the received signals comprising MAC information, and a directional antenna beam being used for communicating with the selected transmitter.