Multimode iterative adaptive smart antenna processing method and apparatus
First Claim
1. A method for performance improvement of a communication receiver receiving signals transmitted from one or more subscriber units, the communication receiver having an array of antenna elements, the method comprising smart antenna processing signals received by each of the antenna elements of the antenna array to provide a smart antenna processed signal, the adaptive smart antenna processing according to a weight vector determined from the signals received by each of the antenna elements, the weight vector determining comprising:
- initializing with a first vector value;
until a switching criterion is met and starting from the first vector value, iteratively modifying the weight vector according to a first adaptive method which minimizes a first cost function, the first adaptive method being an iterative weight determining method with good convergence properties, the final weight vector after the final iteration of the first adaptive method being a second vector value;
starting from the second vector value, modifying the weight vector according to a second adaptive method which minimizes a second cost function, the second adaptive method being a rapidly converging iterative weight determining method, each iteration of both the first and the second adaptive methods comprising determining a copy signal formed from sets of samples from each of the received signals, one set of samples from each received signal, the copy signal formed using the then current weight vector value.
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Abstract
A method and apparatus is described for implementing adaptive smart antenna processing in a receiving communication station that includes an array of antennas and means for adaptive smart antenna processing, the method and apparatus including determining weight vectors for the adaptive smart antenna processing. Using the invention offers advantages when operating in a low SINR environment, for example, in a mobile environment in which the remote users are travelling at high speeds, hence the signals undergo fading. One aspect is hybrid weight adaptation that starts off with a method with good convergence properties, for example, one known to converge in a low SINR environment then switches to a method that converges rapidly, for example when started with relatively high quality initial conditions. To deal with high mobility, the weights determined from data at a particular burst are applied on that particular burst. Such weights may not be optimal for the subsequent bursts. When several users are present in a given channel, a multiport architecture is used to track each individual remote user.
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Citations
33 Claims
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1. A method for performance improvement of a communication receiver receiving signals transmitted from one or more subscriber units, the communication receiver having an array of antenna elements, the method comprising smart antenna processing signals received by each of the antenna elements of the antenna array to provide a smart antenna processed signal, the adaptive smart antenna processing according to a weight vector determined from the signals received by each of the antenna elements, the weight vector determining comprising:
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initializing with a first vector value;
until a switching criterion is met and starting from the first vector value, iteratively modifying the weight vector according to a first adaptive method which minimizes a first cost function, the first adaptive method being an iterative weight determining method with good convergence properties, the final weight vector after the final iteration of the first adaptive method being a second vector value;
starting from the second vector value, modifying the weight vector according to a second adaptive method which minimizes a second cost function, the second adaptive method being a rapidly converging iterative weight determining method, each iteration of both the first and the second adaptive methods comprising determining a copy signal formed from sets of samples from each of the received signals, one set of samples from each received signal, the copy signal formed using the then current weight vector value. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a communication receiver receiving signals transmitted from one or more subscriber units, the communication receiver having an array of antenna elements and adaptive smart antenna processing means, the adaptive smart antenna processing means including means for weighting the signals received by each of the elements of the antenna array in amplitude and phase according to a weight vector for each subscriber unit, the weighting forming a copy signal for the subscriber unit, a method of determining the weight vector for receiving a particular signal transmitted by a particular subscriber unit, the method comprising:
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initializing with a first initial vector value;
until a switching criterion is met and starting from the first initial vector value, iteratively modifying the weight vector according to a first adaptive method which minimizes a first cost function, the first adaptive method being an iterative weight determining method with good convergence properties, the final weight vector after the final iteration of the first adaptive method being a second vector value; and
starting from the second vector value, modifying the weight vector according to a second adaptive method which minimizes a second cost function, the second adaptive method being a rapidly converging iterative weight determining method. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. In a communication receiver receiving signals transmitted from a plurality of subscriber units, the communication receiver having an array of antenna elements and adaptive smart antenna processing means, the adaptive smart antenna processing means including weighting means for weighting the signals received by each of the elements of the antenna array in amplitude and phase according to a weight vector for a particular remote subscriber unit, the weighting forming a copy signal for that subscriber unit, a method of determining the weight vectors for receiving signals transmitted by the plurality of subscriber units, the method comprising:
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for each subscriber unit, initializing with a first initial vector value, the set of first initial vector values being sufficiently mutually independent; and
for each weight vector for each subscriber unit, until a switching criterion is met and starting from the first initial vector value, iteratively modifying the weight vector according to a first adaptive method which minimizes a first cost function, the first adaptive method being an iterative weight determining method with good convergence properties, the final weight vector after the final iteration of the first adaptive method being a second vector value; and
starting from the second vector value, modifying the weight vector according to a second adaptive method which minimizes a second cost function, the second adaptive method being a rapidly converging weight determining method. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. In a communication receiver receiving signals transmitted from one or more subscriber units, the communication receiver having an array of antenna elements and spatio-temporal processing means, the spatio-temporal processing means including means for jointly weighting and time-equalizing the amplitude and phase of the signals received by each of the elements of the antenna array according to a complex valued weight matrix for each subscriber unit, the convolving forming a copy signal for the subscriber unit, a method of determining the weight matrix for receiving a particular signal transmitted by a particular subscriber unit, the method comprising:
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initializing with a first initial matrix value;
until a switching criterion is met and starting from the first initial matrix value, iteratively modifying the weight matrix according to a first adaptive method which minimizes a first cost function, the first adaptive being an iterative weight determining method with good convergence properties, the final weight matrix after the final iteration of the first adaptive method being a second matrix value; and
starting from the second matrix value, iteratively modifying the weight matrix according to a second adaptive method which minimizes a second cost function, the second adaptive method being a rapidly converging weight determining method.
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22. In a communication receiver receiving signals transmitted from one or more subscriber units, the communication receiver comprising an array of antenna elements and adaptive smart antenna processing means, the adaptive smart antenna processing means including means for weighting the signals received by each of the elements of the antenna array in amplitude and phase according to a weight vector for each subscriber unit, the weighting forming a copy signal for the subscriber unit, an apparatus for determining the weight vector for receiving a particular signal transmitted by a particular subscriber unit, the weight determining means comprising:
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initializing means for initializing with a first initial vector value;
first iterative means for iteratively modifying the weight vector according to a first adaptive method which minimizes a first cost function, the first adaptive method being an iterative weight determining method with good convergence properties, second iterative means for iteratively modifying the weight vector according to a second adaptive method which minimizes a second cost function, the second adaptive method being a rapidly converging iterative weight determining method, and a controller for activating the first iterative means starting from the first initial vector value provided by the initializing means until a switching criterion is met, the final weight vector after the final iteration of the first adaptive method being a second vector value, and activating the second iterative means starting from the second vector value to determine the weight vector. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification