Lsi Corporation

Agere Systems Inc.

Daniel Briker

Eliahou Arviv

Gennady Zilberman

Moshe Bukris

Gil Naveh

Yitzhak Casapu

In one embodiment, a method for demodulating and searching for a preamble signal containing a complex phasor signal is disclosed. The complex phasor is demodulated using a phasor-rotated fast transformer. A received signal is correlated with a spreading code to produce a correlated signal. The correlated signal is coherently accumulated to produce a coherently accumulated signal. A first phasor-rotated signal transformation is performed on a real component of the coherently accumulated signal, and a second phasor-rotated signal transformation is performed on an imaginary component of the coherently accumulated signal. Finally, the signal power of the transformed real and imaginary components of the coherently accumulated signal is determined.

Technique for searching for a preamble signal in a spread spectrum using a fast hadamard transform

A method of detecting received data in a communication system includes the steps of: performing a QR decomposition on a received input vector as a function of one or more characteristics of a communication channel over which the input vector was transmitted; generating a subset of best symbol candidates from a symbol constellation by comparing an input sample (corresponding to an element of the input vector) with one or more prescribed thresholds; identifying at least one symbol satisfying prescribed minimum Euclidian distance criteria among multiple ambiguity symbols in the subset of best symbol candidates; and generating a subset of best symbols including a prescribed number of symbols from the symbol constellation determined to be closest to the input sample. The subset of best symbols is used in a subsequent iteration of the steps of generating the subset of best symbol candidates and identifying at least one symbol satisfying the prescribed minimum Euclidian distance criteria.

[object Object]

In one embodiment, a method for signal processing is provided that uses an improved inversion to mitigate the imprecision introduced by fast approximate methods for division. An input signal is received and processed to generate a matrix M. The matrix M is inverted to generate an inverted matrix M. Matrix M is inverted by (i) decomposing the matrix M into a plurality of first sub-matrices, (ii) generating, based on the first sub-matrices and without any division operations, numerators for a plurality of second sub-matrices of the inverted matrix M, (iii) generating, based on the first sub-matrices and without any division operations, denominators for the second sub-matrices, and (iv) generating the second sub-matrices based on the numerators and denominators. The inverted matrix Mis processed to generate an output signal. Accordingly, a reduction in noise level from inaccuracy in division is achieved, and computational complexity is reduced.

Signal processing using modified blockwise analytic matrix inversion

Technique for searching for a preamble signal in a spread spectrum signal using a fast Hadamard transform

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Kfar Saba, Israel

Daniel Briker