Method of subspace beamforming using adaptive transmitting antennas with feedback
First Claim
1. A method for minimizing crosstalk in a wireless communications system comprising an array of transmitting elements and a set of receivers, the method comprising the steps of:
- transmitting from the array to the receivers a set of transmitted signals chosen from the group consisting of a set of information signals and a set of probing signals, where the transmitting is in accordance with a set of initial weight vectors;
feeding back to the array a set of feedback signals, where each of the feedback signals is derived from the response at one of the receivers to the set of transmitted signals;
calculating from the set of feedback signals a set of new information weight vectors that minimize time-average crosstalk between the receivers and maximize time-average desired signal at each receiver; and
transmitting the set of information signals from the array to the receivers in accordance with the set of new information weight vectors.
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Abstract
A method is disclosed for using feedback to reduce crosstalk between mobile receivers in a wireless communications system comprising an adaptive transmitting antenna array. Feedback signals from the receivers are time-averaged and used to calculate a set of weight vectors that minimize crosstalk and maximize desired signal without requiring burdensome feedback rates. Beamforming diversity is combined with feedback through the use of diversity vectors. The preferred embodiment includes a method for obtaining the required feedback by exploiting the SAT circuitry present in the AMPS system currently in use. Consequently, the method may be implemented without modification to existing cellular phone handsets.
244 Citations
10 Claims
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1. A method for minimizing crosstalk in a wireless communications system comprising an array of transmitting elements and a set of receivers, the method comprising the steps of:
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transmitting from the array to the receivers a set of transmitted signals chosen from the group consisting of a set of information signals and a set of probing signals, where the transmitting is in accordance with a set of initial weight vectors; feeding back to the array a set of feedback signals, where each of the feedback signals is derived from the response at one of the receivers to the set of transmitted signals; calculating from the set of feedback signals a set of new information weight vectors that minimize time-average crosstalk between the receivers and maximize time-average desired signal at each receiver; and transmitting the set of information signals from the array to the receivers in accordance with the set of new information weight vectors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification