Spatial joint searcher and channel estimators
First Claim
1. A wireless communication receiver comprising:
- an antenna array which comprises plural antennas, the plural antennas providing respective plural signals indicative of an arriving wavefront;
a joint searcher and channel estimator which essentially concurrently considers the plural signals provided by the plural antennas for determining both a time of arrival and channel coefficient.
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Abstract
A wireless communication receiver (20) comprises an antenna array (22) and a joint searcher and channel estimator (24). Plural antenna elements of the array provide respective plural signals (indicative of one or more arriving wavefronts) to the joint searcher and channel estimator. The joint searcher and channel estimator essentially concurrently considers the plural signals provided by the plural antennas for determining both a time of arrival and composite channel coefficient for each wavefront. The joint searcher and channel estimator applies the channel coefficient and the time of arrival to a detector which provides, e.g., a symbol estimate. Since it contemporaneously processes the signals from plural antennas over a sampling window in order to determine both time of arrival and the channel coefficient, the joint searcher and channel estimator (24) is considered a two dimensional unit. A first dimension is with reference to a time index of the sampling window, i.e., a sampling window time index. A second dimension is a spatial dimension imparted by the spacing of the plural antennas of the array. The spatial joint searcher and channel estimator may take differing embodiments and have differing implementations. In one example, illustrative embodiment the joint searcher and channel estimator includes a non-parametric type correlator (e.g., a correlator which performs a Fast Fourier Transform (FFT) calculation). In another example, illustrative embodiment the joint searcher and channel estimator utilizes a parametric approach.
33 Citations
38 Claims
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1. A wireless communication receiver comprising:
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an antenna array which comprises plural antennas, the plural antennas providing respective plural signals indicative of an arriving wavefront;
a joint searcher and channel estimator which essentially concurrently considers the plural signals provided by the plural antennas for determining both a time of arrival and channel coefficient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 17, 18, 19, 20)
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13. The apparatus of 11, wherein each of the plural possible frequencies for the dimensional receptivity vector represents a different possible direction of arrival of the arriving wavefront.
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14. The apparatus of 11, wherein the correlator output comprises Y(n,t), and wherein the correlator output analyzer determines a maximum absolute value |Y(n,t)|max, wherein the analyzer uses a sampling window time index t_max at which |Y(n,t)|max occurs as the time of arrival of the arriving wavefront;
- and wherein the s analyzer uses the a frequency index n_max at which |Y(n,t)|max occurs as the direction of arrival of the arriving wavefront.
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15. The apparatus of 14, wherein the correlator output comprises Y(n,t), and wherein for each arriving wavefront the correlator output analyzer determines a qualifying absolute value |Y(n,t)|max, wherein the analyzer uses a sampling window time index t_max at which |Y(n,t)|max occurs as the time of arrival of the arriving wavefront;
- and wherein the analyzer uses the a frequency index n_max at which IY(n,t)lmax occurs as the direction of arrival of the arriving wavefront.
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16. The apparatus of 11, wherein the correlator output comprises Y(n,t), and wherein the analyzer determines a maximum absolute value |Y(n,t)|max, wherein the analyzer obtains an amplitude for the arriving wavefront by dividing |Y(n,t)|max by a number of antennas comprising the antenna array.
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21. A method of operating a wireless communication receiver comprising:
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obtaining from plural antennas of an antenna array respective plural signals indicative of an arriving wavefront;
concurrently using the plural signals provided by the plural antennas for determining both a time of arrival and channel coefficient. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 35, 36, 37, 38)
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30. The method of 29, wherein for each combination of plural possible frequencies and plural time indexes, the method comprises evaluating the following expression:
Y(n,t)=Σ
Cj*FFT(n,X(;
,t)),j=1,Kwherein Cj is a coding sequence symbol value j and K is a length of the coding sequence.
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31. The method of 28, wherein each of the plural possible frequencies for the dimensional receptivity vector represents a different possible direction of arrival of the arriving wavefront.
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32. The method of 28, wherein the correlator output comprises Y(n,t), and further comprising determining a maximum absolute value |Y(n,t)|max.
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33. The method of 32, further comprising:
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selecting a sampling window time index t_max at which |Y(n,t)|max occurs as the time of arrival of the arriving wavefront; and
selecting a frequency index n_max at which |Y(n,t)|max occurs as the direction of arrival of the arriving wavefront.
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34. The method of 32, further comprising determining an amplitude for the arriving wavefront by dividing |Y(n,t)|max by a number of antennas comprising the antenna array.
Specification