Method and system for steering antenna beam

• US 20070135167A1
• Filed: 12/08/2005
• Published: 06/14/2007
• Est. Priority Date: 12/08/2005
• Status: Active Grant

• Current Assignee: Accton Technology Corporation
• Original Assignee: Accton Technology Corporation
• Inventors: Liu, I-Ru
• Granted Patent: US 7,613,482 B2
• Time in Patent Office: Days
• US Class Current: 455/562.100
• CPC Class Codes: H01Q 21/06 Arrays of individually energised antenna units similarly polarised and spaced apart
• CPC Class Codes: H01Q 3/2617 Array of identical elements
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Abstract

A hybrid wireless network system is disclosed. The hybrid wireless network system includes an antenna array, an analog subsystem, and a digital subsystem. The antenna array at least includes two antenna elements. In the case of using multiple antenna elements to extend link range and coverage, a coarse-fine method is included for antenna elements selection. The analog subsystem calculates a difference signal and a sum signal based on the two RF signals. The analog subsystem includes step leveling devices. The digital subsystem estimates a direction-of-arrival (DOA) based on the sum signal and the difference signal. The step-leveling devices receive weights from the digital subsystem, in form of a feedback control, to apply the weights on the two RF signals respectively. The digital subsystem repetitively calculates new weights to update a beam pattern formed by the two RF signals until the DOA approaches null.

Claims

1. A hybrid wireless network system for steering antenna beams, comprising:

an antenna array, receiving at least two RF signals;

an analog subsystem comprising;

a step leveling device coupling to the antenna array;

a magic-Tee coupler connected to the step leveling device for calculating a difference signal and a sum signal based on the two RF signals; and

a phase-sensing comparator for calculating a polarity data based on the comparison of the difference signal and the sum signal; and

a digital subsystem comprising a transceiver and a receiver, estimating a direction-of-arrival (DOA) based on the difference signal and the polarity data, and generating weights based on the DOA; and

wherein the step-leveling device receive the weights from the digital subsystem, in form of a feedback control, to apply the weights on the two RF signals respectively;

wherein the digital subsystem repetitively calculates new weights to update a beam pattern of the antenna array until the DOA approaches null.

2. The system according to claim 1, wherein the antenna array comprises amplitude-compared antenna elements.

3. The system according to claim 1, wherein the antenna array comprises phased antenna elements, the analog subsystem further comprising:

a microwave coupling unit (90°

hybrid coupler), for converting phase signals received by the phase-comparison antenna elements into amplitude signals.

4. The system according to claim 1, wherein the digital subsystem further comprises:

a media access control (MAC) connected to the transceiver; and

a baseband processor (BBP) connected to the MAC for processing signals to and from a network via the antenna array.

5. The system according to claim 1, wherein the DOA is calculated by correlating the difference signal to the polarity data.

6. The system according to claim 1, wherein the antenna array has two antenna elements.

7. The system according to claim 6, wherein the analog subsystem further comprises a diversity switch connected between the antenna array and the step leveling device for selectively connecting one of the antenna elements to the step leveling device.

8. The system according to claim 7, wherein the device further comprising an additional antenna array to extend link coverage.

9. A method for steering antenna beams of a network system, the method comprising:

receiving at least two RF signals based on initial weights via an antenna array;

calculating a difference signal and a sum signal based on amplitudes of the two RF signals;

calculating a polarity data based on the difference signal and the sum signal; and

estimating direction-of-arrival (DOA) of the RF signals based on the polarity data and the difference signal.

10. The method according to claim 9, wherein the polarity data is calculated based on the comparison of polarities of the difference signal and the sum signal.

11. The method according to claim 9, wherein the estimating DOA step comprises generating the estimated DOA by correlating the difference signal to the polarity data.

12. The method according to claim 9, further comprising:

calculating new weights for the two RF signals based on the DOA; and

continuously updating the antenna beams using the new weights via virtue of feedback until the DOA approaches null.

13. The method according to claim 9, wherein the network system comprising an antenna array having antenna element pairs that are symmetrically disposed with respect to an array bore site such that an antenna element to the left of the bore site has a corresponding antenna element to the right of the bore site, the method further comprising:

performing at least one of a coarse mode and a fine mode to calculate weights and apply the weights to RF signals received by the antenna array, so as to locate a direction of arrival (DOA) of the RF signals;

wherein the coarse mode comprises selecting an inner antenna element pair closer to the bore site to calculate coarse weights; and

wherein the fine mode comprises selecting an outer antenna element pair farther from the bore site to calculate fine weights.

14. The method according to claim 13, wherein the fine weights are calculated based on multiplying the coarse weights by a set of coefficients.

15. The method according to claim 13, wherein the fine weights are calculated based on the outer antenna element pair and the coarse weights.

16. The method according to claim 13, wherein the coarse weights and the fine weights each comprise tracking weights, the method further comprising:

checking if signal quality of the RF signals is abnormal under current mode of operation, if yes, switching the current mode of operation, the current mode of operation being either the coarse mode or the find mode; and

if the signal quality is not abnormal, applying the calculated weights under the current mode of operation and keeping the tracking weights to the direction of the RF signals.