Reduced complexity channel estimation for wireless communication systems
First Claim
1. A method used in a wireless communication system, comprising:
- obtaining an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one; and
obtaining an intermediate matrix for the DFT matrix.
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Abstract
Techniques to derive a channel estimate using substantially fewer number of complex multiplications than with a brute-force method to derive the same channel estimate. In one method, an intermediate vector B is initially derived based on K sub-vectors of a vector Ĥ for a channel frequency response estimate and at least two DFT sub-matrices for a DFT matrix {tilde over (W)}, where K>1. An intermediate matrix A for the DFT matrix {tilde over (W)} is also obtained. A least square channel impulse response estimate is then derived based on the intermediate vector B and the intermediate matrix A. In one implementation, the intermediate vector B is obtained by first computing DFTs of a matrix ĤT×L, which is formed based on the vector Ĥ, to provide a matrix GL×L. Inner products between the columns of a base DFT sub-matrix W1 and the rows of the matrix GL×L are then computed to obtain the entries of the intermediate vector B.
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Citations
18 Claims
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1. A method used in a wireless communication system, comprising:
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obtaining an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one; and obtaining an intermediate matrix for the DFT matrix. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method used in a wireless communication system, comprising:
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obtaining an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and K discrete Fourier transform (DFT) sub-matrices of a DFT matrix, where K is an integer greater than one; and obtaining an intermediate matrix derived based on the K DFT sub-matrices.
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11. A method used in an orthogonal frequency division multiplexing (OFDM) communication, comprising:
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forming a first matrix for an initial frequency response estimate of the wireless channel; computing discrete Fourier transforms (DFTs) of the first matrix to obtain a second matrix; computing inner products between a base DFT sub-matrix and the second matrix to obtain an intermediate vector; and obtaining an intermediate matrix derived for a DFT matrix for the initial frequency response estimate.
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12. An apparatus, comprising:
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at least one processor configured to obtain an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one, and obtain an intermediate matrix for the DFT matrix; and a memory coupled to the at least one processor.
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13. An apparatus used in a wireless communication system comprising:
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means for obtaining an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one; and means for obtaining an intermediate matrix for the DFT matrix. - View Dependent Claims (14)
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15. A device in a wireless communication system, comprising:
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a demodulator operative to receive a pilot transmission on a group of designated subbands; and a processor operative to obtain a first channel estimate for the group of designated subbands based on the received pilot transmission, obtain an intermediate vector derived based on K sub-vectors of a vector for the first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one, and obtain an intermediate matrix for the DFT matrix. - View Dependent Claims (16)
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17. A processor-readable medium with instructions used in a wireless communication system, the instructions for:
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obtaining an intermediate vector derived based on K sub-vectors of a vector for a first channel estimate and at least two discrete Fourier transform (DFT) sub-matrices for a DFT matrix, wherein the DFT matrix corresponds to the vector for the first channel estimate and K is an integer greater than one; and obtaining an intermediate matrix for the DFT matrix. - View Dependent Claims (18)
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Specification