Control of a multi-sectored antenna system to improve channel efficiency

• US 20060171357A1
• Filed: 01/28/2005
• Published: 08/03/2006
• Est. Priority Date: 01/28/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Giaimo, Edward C. III, King, Wayne G., Russo, David William, Murzanski, Chris A., Brennan, James, Ranta, Craig Steven, Stegner, Stephen M.
• Granted Patent: US 7,359,362 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams

Abstract

A wireless device is coupled to a multi-sector antenna that includes a plurality of different sectors, any of which can be activated to transmit and receive in a desired direction specific to that sector. Optionally, an omnidirectional antenna is included for initially establishing a wireless connection with another wireless device, such as an access point. A parameter indicative of signal quality, such as throughput or received signal strength indication (RSSI) is determined by polling with each antenna sector to establish a prioritized candidate list. If a receive Trigger becomes active in response to a parameter falling below a threshold level, a new candidate sector is selected from the current list based upon a next-best signal quality. The directionality of the multi-sector antenna provides a substantially higher data rate compared to that of the conventional omnidirectional antenna.

Claims

1. A method for conducting wireless radio frequency (RF) communications with a wireless device using an antenna that is coupled to the wireless device and is able to transmit and receive an RF signal in a desired direction, with a relatively high gain, wherein the desired direction is selectable from a plurality of different directions in which the antenna can transmit and receive an RF signal, comprising the steps of:

(a) associating the wireless device in a communication link with another wireless device;

(b) determining a signal quality for RF communications with the other wireless device using the antenna, for each of at least some of the plurality of different directions; and

(c) based upon signal qualities determined, selecting an initial desired direction for the antenna to be used for communicating with the other wireless device, the initial desired direction being selected by evaluating the signal qualities that were determined to select a direction in which a value of the signal quality was optimum.

2. The method of claim 1, further comprising the steps of:

(a) determining a candidate list of directions for transmitting and receiving RF signals while communicating with the other wireless device with the antenna, based upon the signal qualities determined for at least some of the different directions, wherein entries in the candidate list are prioritized based upon the signal quality in the different directions; and

(b) in response to a change in the signal quality, selecting another direction from the candidate list, as a new desired direction for communicating with the other wireless device.

3. The method of claim 1, wherein the signal quality comprises at least one of a plurality of parameters, including:

(a) a data throughput over the communication link;

(b) a success in communicating data over the communication link;

(c) a received signal strength indication (RSSI);

(d) a retry count accumulated before successfully transmitting data over the communication link;

(e) an RSSI of a returned acknowledgement (ACK) from the other wireless device;

(f) a signal-to-noise ratio;

(g) an average determined over time of at least one of the parameters (a) through (f).

4. The method of claim 1, wherein the antenna comprises a multi-sector antenna and each different direction corresponds to a different sector of the multi-sector antenna, so the step of selecting the initial desired direction for the antenna comprises the step of selecting one of the sectors of the multi-sector antenna for communicating with the other wireless device.

5. The method of claim 2, wherein the step of determining the candidate list of directions for transmitting and receiving RF signals with the antenna comprises the step of re-determining the signal quality for each direction of the antenna immediately before determining the candidate list, so that a current signal quality in each of the different directions is used in determining the candidate list.

6. The method of claim 1, wherein the step of associating the wireless device in the communication link with the other wireless device comprises the step of using an omnidirectional antenna to initially detect and authenticate with the other wireless device, the wireless device communicating with the other wireless device over the omnidirectional antenna at a relatively lower data rate than that used for communicating with the other wireless device in the initial desired direction using the antenna.

7. The method of claim 1, wherein the step of associating the wireless device in the communication link with the other wireless device comprises the step of scanning available communication channels in at least some of the different directions until a communication with the other wireless device is established on one of the communication channels.

8. A memory medium having machine instructions for carrying out the steps of claim 1.

9. A wireless station that is controllable to transmit and receive wireless radio frequency (RF) signals in a selected desired direction at a relatively high data rate compared to a data rate that would be achieved if the RF signals were transmitted and received omnidirectionally, comprising:

(a) a wireless transceiver;

(b) an antenna that is coupled to the wireless transceiver and is controllable to transmit and receive RF signals in a desired direction automatically selected from a plurality of different directions in which the antenna can be caused to transmit and receive the RF signals;

(c) a processor that is coupled to the antenna to select the desired direction in which it is used for communicating with the RF signals; and

(d) a memory coupled to the processor, for storing machine language instructions, the processor executing the machine language instructions, causing the processor to;

(i) establish a communication link with another wireless device;

(ii) determine a signal quality for RF communications conducted with the other wireless device using the antenna, for each of at least some of the plurality of different directions; and

(iii) based upon signal qualities determined, select an initial desired direction for the antenna to be used for communicating with the other wireless device, the initial desired direction being selected by evaluating the signal qualities that were determined, to select a direction as the initial desired direction for which a value of the signal quality was optimum.

10. The wireless station of claim 9, wherein the machine language instructions further cause the processor to:

(a) determine a candidate list of directions for transmitting and receiving RF signals, while communicating with the other wireless device using the antenna, based upon the signal qualities determined for at least some of the different directions, wherein the directions included on the candidate list are prioritized based upon the signal quality determined for each direction; and

(b) in response to a change in the signal quality, select another direction from the candidate list as a new desired direction for communicating with the other wireless device.

11. The wireless station of claim 9, wherein the signal quality comprises at least one of a plurality of parameters, including:

(a) a data throughput over the communication link;

(b) a success in communicating data over the communication link;

(c) a received signal strength indication (RSSI);

(d) a retry count accumulated before successfully transmitting data over the communication link;

(e) an RSSI of a returned acknowledgement (ACK) from the other wireless device;

(f) a signal-to-noise ratio;

(g) an average determined over time of at least one of the parameters (a) through (f).

12. The wireless station of claim 9, wherein the antenna comprises a multi-sector antenna and each different direction corresponds to a different sector of the multi-sector antenna, and wherein the machine language instructions cause the processor to select one of the sectors of the multi-sector antenna for communicating with the other wireless device, where the sector that is selected transmits and receives in the initial desired direction determined by the processor.

13. The wireless station of claim 10, wherein the machine language instructions further cause the processor to re-determine the signal quality for each direction of the antenna immediately before determining the candidate list, so that a current signal quality in each of the different directions is used in determining the candidate list.

14. The wireless station of claim 9, further comprising a switch that is coupled to an omnidirectional antenna, to the antenna, and to the wireless transceiver, the machine language instructions further causing the processor to active the switch so as to use the omnidirectional antenna to initially detect and authenticate with the other wireless device, the wireless station communicating with the other wireless device over the omnidirectional antenna at a relatively lower data rate than that used for communicating with the other wireless device in the initial desired direction using the antenna.

15. The wireless station of claim 9, wherein the machine language instructions further cause the processor to use the wireless transceiver and antenna to scan available communication channels in at least some of the different directions until a communication with the other wireless device is established on one of the communication channels.

16. A method for controlling a direction in which radio frequency (RF) signals are transmitted and received by a client device that is communicating with an access point in a wireless network, comprising the steps of:

(a) establishing a communication link between the client device and the access point;

(b) selecting an initial direction that provides a best signal quality for the RF signals communicated between the client device and the access point using an antenna that is steerable to a plurality of different directions when transmitting and receiving the RF signals;

(c) enabling communication with the access point in the initial direction by controlling the antenna to communicate RF signals in the initial direction.

17. The method of claim 16, further comprising the steps of:

(a) automatically determining a signal quality associated with communication with the access point in each of a plurality of different directions by steering the antenna to each of said plurality of different directions and detecting a value for the signal quality at each different direction; and

(b) automatically prioritizing directions for communication with the access point based upon the signal quality detected for each of said different directions.

18. The method of claim 17, further comprising the step of responding to a deterioration of communication with the access point in a current direction by selecting a new direction for communication with the access point with the antenna, the new direction being automatically selected based upon a priority of the new direction compared to the priority of other directions.

19. The method of claim 16, wherein the step of establishing the communication link between the client device and the access point is carried out with RF signals conveyed by an omnidirectional antenna.

20. The method of claim 16, wherein the signal quality comprises at least one of a plurality of parameters, including:

(a) a data throughput when communicating with the access point;

(b) a success in communicating data between the access point and the client device;

(c) a received signal strength indication (RSSI);

(d) a retry count accumulated before successfully transmitting data between the access point and the client device;

(e) an RSSI of a returned acknowledgement (ACK) from the access point;

(f) a signal-to-noise ratio;

(g) an average determined over time of at least one of the parameters (a) through (f).