Method and apparatus for robust estimation of directions of arrival for antenna arrays
First Claim
1. A method of operating a direction of arrival (DOA)-aided digital beam forming (DBF) subsystem, wherein a direction of arrival estimator (DOAE) determines direction of arrival (DOA) estimates for incident signals received by an array antenna, said method comprising the steps of:
- calculating a composite power pattern for a plurality of points within a desired field of view;
deriving said DOA estimates for said incident signals by applying at least one peak-finding technique to said composite power pattern;
establishing a beam in a direction substantially equal to a DOA estimate for one of said incident signals, when said one of said incident signals is a desired signal; and
directing nulls in directions substantially equal to DOA estimates for others of said incident signals, when said others are undesired sources.
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Accused Products
Abstract
A direction of arrival (DOA)-aided digital beamforming (DBF) subsystem (300 FIG. 3) is provided for mitigating interference and increasing the frequency reuse factor in communication systems. The DOA-aided DBF subsystem is used to accurately position beams and nulls in at least one antenna beam pattern. By accurately directing beams at desired locations and nulls at undesired locations, the DOA-aided DBF subsystem provides a more efficient processing of antenna beam patterns in communication systems. The DOA-aided DBF subsystem is used in geostationary satellites, non-geostationary satellites, and terrestrial communication devices. The DOA-aided DBF subsystem uses a unique algorithm to determine DOA information that allows more efficient beam management and allows more subscribers to be served, while saving spectrum and power.
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Citations
27 Claims
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1. A method of operating a direction of arrival (DOA)-aided digital beam forming (DBF) subsystem, wherein a direction of arrival estimator (DOAE) determines direction of arrival (DOA) estimates for incident signals received by an array antenna, said method comprising the steps of:
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calculating a composite power pattern for a plurality of points within a desired field of view; deriving said DOA estimates for said incident signals by applying at least one peak-finding technique to said composite power pattern; establishing a beam in a direction substantially equal to a DOA estimate for one of said incident signals, when said one of said incident signals is a desired signal; and directing nulls in directions substantially equal to DOA estimates for others of said incident signals, when said others are undesired sources. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. In an antenna array comprising a plurality of antenna elements, wherein a plurality of incident signals are received at said antenna array, a method for deriving a direction of arrival (DOA) estimate for one of said plurality of incident signals, said method comprising the steps of:
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downconverting said plurality of incident signals into a plurality of digital received signals; determining, by a digital beamformer, a plurality of digital baseband signals from said plurality of digital received signals; and processing, by a direction of arrival estimator (DOAE), said plurality of digital baseband signals. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A direction of arrival (DOA)-aided digital beamforming (DBF) subsystem comprising:
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at least one antenna array having a plurality of elements; a plurality of receive/transmit (Rx/Tx) modules coupled to said plurality of elements; a digital beamformer (DBF) coupled to said plurality of Rx/Tx modules, said DBF controlling N elements of said plurality of elements to establish a plurality of beams; a direction of arrival estimator (DOAE) coupled to said DBF, said DOAE for determining direction of arrival (DOA) estimates for said plurality of beams; a controller coupled to said DBF and to said DOAE; means for selecting a first receive subarray of said plurality of elements as a reference array; means for selecting a second receive subarray of said plurality of elements; means for combining weighted received signals from said second receive subarray and reference array signals from said first receive subarray; means for determining a complex baseband signal covariance matrix C for said first receive subarray; means for determining a complex cross-correlation vector d using said first receive subarray and said second receive subarray; means for determining a complex weight vector w that minimizes received power at said at least one antenna array; means for determining a normalized pattern for said at least one antenna array using said complex weight vector w; and means for determining said direction of arrival estimates using at least one maximum point in said normalized pattern.
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27. A direction of arrival (DOA)-aided digital beamforming (DBF) subsystem comprising:
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at least one antenna array having a plurality of elements; a plurality of receive/transmit (Rx/Tx) modules coupled to said plurality of elements; a digital beamformer (DBF) coupled to said plurality of Rx/Tx modules, said DBF controlling N elements of said plurality of elements to establish a plurality of beams; a direction of arrival estimator (DOAE) coupled to said DBF, said DOAE for determining direction of arrival (DOA) estimates for said plurality of beams; a controller coupled to said DBF and to said DOAE; means for selecting a first receive subarray of said plurality of elements as a reference array; means for selecting a second receive subarray of said plurality of elements; means for combining weighted received signals from said second receive subarray and reference array signals from said first receive subarray; means for determining a complex baseband signal covariance matrix C for said first receive subarray; means for determining a complex cross-correlation vector d using said first receive subarray and said second receive subarray; means for determining a complex weight vector w that minimizes received power at said at least one antenna array; means for determining a composite pattern for said at least one antenna array using said complex weight vector w; and means for determining said direction of arrival estimates using at least one minimum point in said composite pattern.
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Specification