Channel estimating reference signal processor for communication system adaptive antennas
First Claim
1. An antenna array adaptive signal processor for improving the signal-to-noise ratio of a received signal containing a direct component and multipath components in an unknown electromagnetic environment comprising:
- signal conducting means for carrying a plurality of signals from antenna elements along a plurality of preselected paths,filter means connected between said array signal and each of said signal conducting means to minimize the mean square error of said array signal as compared with a reference signal, whereby said array signal is formed in a selected look direction, andadaptive channel estimating means for generating said reference signal so that said reference signal includes the direct component as well as the multipath components of the received signal.
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Accused Products
Abstract
A spread spectrum communication adaptive array antenna processor is disclosed which can acquire and remain synchronized to a pseudo-noise (PN) signal transmitted in a multipath signal environment. The plurality of antennas which receive rf signals are individually associated with mixing circuitry which reduces the received signals to IF frequencies. The IF signals are fed into the adaptive filtering portion of the adaptive signal processor which contains circuits to generate an adaptive weight corresponding to each antenna element. An array signal is formed by summing the products of each IF signal with a filter weight corresponding to each antenna element generated within each respective adaptive loop. The adaptive signal processor utilizes the complex conjugate of the error feedback signal which is then multiplied by each respective IF signal. The complex conjugate of this integrated product forms each filter weight. A channel estimator generates an adaptive reference signal which inclues the essential multipath characteristics of the received signal. By using this reference signal in conjunction with the array signal generated by the adaptive filtering portion of the processor, the adaptive array can form an appropriate main beam without prior knowledge of the signal propagation direction.
80 Citations
6 Claims
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1. An antenna array adaptive signal processor for improving the signal-to-noise ratio of a received signal containing a direct component and multipath components in an unknown electromagnetic environment comprising:
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signal conducting means for carrying a plurality of signals from antenna elements along a plurality of preselected paths, filter means connected between said array signal and each of said signal conducting means to minimize the mean square error of said array signal as compared with a reference signal, whereby said array signal is formed in a selected look direction, and adaptive channel estimating means for generating said reference signal so that said reference signal includes the direct component as well as the multipath components of the received signal. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification