Method and apparatus for interference rejection with different beams, polarizations, and phase references
First Claim
1. A method for reducing the effects of signal fading, time dispersion, and interference in a radio communications system, comprising the steps of:
- (a) receiving a radio signal on at least one antenna element representing a transmitted symbol sequence;
(b) processing said radio signal to produce received signal samples for said at least one antenna;
(c) estimating a channel tap for said at least one antenna to a produce a channel tap estimate;
(d) estimating scalar impairment correlation properties among the received signal samples to produce an estimate of scalar impairment correlation properties;
(e) forming scalar branch metrics in a scalar branch metric processor using said received signal samples, said channel tap estimate, and said scalar estimate of impairment correlation properties; and
(f) employing said scalar branch metrics in a sequence estimation algorithm to estimate said transmitted symbol sequence.
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Accused Products
Abstract
A digital radio communication system includes processing to jointly mitigate the deleterious effects of fading, time dispersion and interference using interference rejection and diversity combining. The system employs a selection processor for preliminarily reducing the number of signals for interference rejection and diversity combining based on one or more criterion. The system accommodates signals from dual polarized antennas. In one particular embodiment, the system performs interference rejection and diversity combining by separating a received signal into its in-phase and quadrature components.
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Citations
48 Claims
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1. A method for reducing the effects of signal fading, time dispersion, and interference in a radio communications system, comprising the steps of:
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(a) receiving a radio signal on at least one antenna element representing a transmitted symbol sequence; (b) processing said radio signal to produce received signal samples for said at least one antenna; (c) estimating a channel tap for said at least one antenna to a produce a channel tap estimate; (d) estimating scalar impairment correlation properties among the received signal samples to produce an estimate of scalar impairment correlation properties; (e) forming scalar branch metrics in a scalar branch metric processor using said received signal samples, said channel tap estimate, and said scalar estimate of impairment correlation properties; and (f) employing said scalar branch metrics in a sequence estimation algorithm to estimate said transmitted symbol sequence. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for reducing the effects of signal fading, time dispersion, and interference in a radio communications system, comprising:
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means for receiving a radio signal on at least one antenna element representing a transmitted symbol sequence; means for processing said radio signal to produce received signal samples for said at least one antenna; means for estimating a channel tap for said at least one antenna to a produce a channel tap estimate; means for estimating scalar impairment correlation properties among said radio signal samples to produce an estimate of scalar impairment correlation properties; means for forming scalar branch metrics in a scalar branch metric processor using said received signal samples, said channel tap estimates, and said scalar estimate of impairment correlation properties; and means for employing said scalar branch metrics in a sequence estimation algorithm to estimate said transmitted symbol sequence. - View Dependent Claims (7, 8, 9, 10)
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11. A method for reducing degradation in a transmitted signal sequence comprising the step of:
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(a) providing a number of radio signals representing said transmitted signal sequence; (b) selecting a second number of signals from said number of radio signals using a selection processor on the basis of one or more selection criterion, where said second number is less than said first number; (c) processing said second number of signals to generate an estimate of said transmitted signal sequence; wherein said step (c) further comprises the steps of; (d) receiving said second number of signals from said selection processor; (e) processing said second number of signals to produce received signal samples; (f) estimating channel taps for said signals to produce channel tap estimates; (g) estimating impairment correlation properties among said received signals to produce an estimate of impairment correlation properties; (h) forming branch metrics in a branch metric processor using said received signal samples, said channel tap estimates, and said estimate of impairment correlation properties; and (i) employing said scalar branch metrics in a sequence estimation algorithm to estimate said transmitted symbol sequence. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 31, 32, 33)
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21. An apparatus for reducing degradation in a transmitted signal sequence comprising:
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(a) means for providing a first number of radio signals representing said transmitted signal sequence; (b) means for selecting a second number of signals from said first number of radio signals using a selection processor on the basis of one or more selection criterion, where said second number is less than said first number; (c) means for processing said second number of signals to generate an estimate of said transmitted signal sequences; wherein said means for processing further comprises; means for receiving said second number of signals from said selection processor; means for processing said second number of signals to produce received signal samples; means for estimating channel taps for said signals to produce channel tap estimates; means for estimating impairment correlation properties among said received signals to produce an estimate of impairment correlation properties; means for forming branch metrics in a branch metric processor using said received signal samples, said channel tap estimates, and said estimate of impairment correlation properties; and means for employing said scalar branch metrics in a sequence estimation algorithm to estimate said transmitted symbol sequence. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 34, 35, 36)
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37. A method for reducing the effects of signal fading, time dispersion, and interference in a radio communications system, comprising the steps of:
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(a) receiving a signal representing a transmitted symbol sequence on plural antenna elements; (b) processing said signal to produce received signal samples for each of said plural antenna elements; (c) estimating channel taps for said plural antenna elements to a produce channel tap estimates; (d) estimating impairment correlation properties among said received signals to produce an estimate of impairment correlation properties; (e) forming branch metrics in a branch metric processor using said received signal samples, said channel tap estimates, and said estimate of impairment correlation properties; and (f) employing said branch metrics in a sequence estimation algorithm to estimate said transmitted symbol sequence, wherein said plural antenna elements include at least a first element producing a first polarization, and a second element producing a second polarization. - View Dependent Claims (38)
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39. An apparatus for reducing the effects of signal fading, time dispersion, and interference in a radio communications system, comprising:
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plural antenna elements for receiving a signal representing a transmitted symbol sequence; processing logic for processing said signal to produce received signal samples for each said plural antenna elements; a first estimator for estimating channel taps for said plural antenna elements to a produce channel tap estimates; a second estimator for estimating impairment correlation properties among said received signals to produce an estimate of impairment correlation properties; a branch metric processor for forming branch metrics using said received signal samples, said channel tap estimates, and said estimate of impairment correlation properties; and logic for employing said branch metrics in a sequence estimation algorithm to estimate said transmitted symbol sequence, wherein said plural antenna elements include at least a first element producing a first polarization, and a second element producing a second polarization. - View Dependent Claims (40)
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41. In a digital communications system for transmitting a sequence of digital symbols, a method for reducing the effects of signal fading, time dispersion, and interference in a radio communications system, comprising the steps of:
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(a) receiving a number of radio signals; (b) selecting groups of radio signals using a selection processor; (c) processing each group of radio signals to produce branch metrics; (d) adding said branch metrics from different groups to produce combined branch metrics; and (e) employing said combined branch metrics in a sequence estimation algorithm to estimate said transmitted symbol sequence. - View Dependent Claims (42)
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43. An apparatus for reducing the effects of signal fading, time dispersion, and interference in a radio communications system, comprising:
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means for receiving a number of radio signals representing a transmitted sequence of symbols; means for selecting groups of radio signals using a selection processor; a plurality of processing means, each for processing a respective group of radio signals, to produce branch metrics; means for adding said branch metrics from different groups to produce combined branch metrics; and means for employing said combined branch metrics in a sequence estimation algorithm to estimate said transmitted symbol sequence. - View Dependent Claims (44)
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45. A method for reducing degradation in a transmitted signal sequence comprising the step of:
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(a) receiving a number of radio signals from a plurality of antenna elements, a first group of said antenna elements using a first polarization and a second group of said antenna elements using a second polarization; (b) processing said radio signals in at least one beamforming processor to produce a first number of radio signals; (c) selecting a second number of radio signals from said first number of radio signals using a selection processor on the basis of one or more selection criterion, where said second number is less than said first number, and said second number is greater than 1; and (d) processing said second number of signals to generate an estimate of said transmitted signal sequence using a sequence estimation algorithm employing branch metrics; wherein said step (c) is constrained to select at least one signal having a first polarization, and at least one signal having a second polarization, wherein the first polarization is orthogonal to said second polarization. - View Dependent Claims (46)
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47. An apparatus for reducing degradation in a transmitted signal sequence comprising:
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a plurality of antenna elements for receiving a number of radio signals, a first group of said antenna elements using a first polarization and a second group of said antenna elements using a second polarization; at least one beamformer for processing said radio signals to produce a first number of radio signals; a selector for selecting a second number of radio signals from said first number of radio signals using a selection processor on the basis of one or more selection criterion, where said second number is less than said first number, and said second number is greater than 1; and a processor for processing said second number of signals to generate an estimate of said transmitted signal sequence using a sequence estimation algorithm employing branch metrics; wherein said selector is constrained to select at least one signal having a first polarization, and at least one signal having a second polarization, wherein the first polarization is orthogonal to said second polarization. - View Dependent Claims (48)
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Specification