Patent ID: 7869546
Filing Date: 2011-01-11
Classification: G06F,H04J

Abstract:
1. A method of detecting a symbol sequence contained in a received signal comprising a cyclic convolution of a Walsh code multiplexed signal and a channel impulse response of a multipath channel, the method comprising: calculating a transformation matrix that relates the Walsh Hadamard Transform (WHT) domain spectra of the data signal and the WHT domain spectra of the channel impulse response to the received signal; and estimating the symbol sequence as a function of the transformation matrix and the received signal, by inverting the transformation matrix and multiplying the received signal by the inverse of the transformation matrix; wherein calculating the transformation matrix is based on applying similarity transforms to the WHT domain spectra of the channel impulse response, wherein the similarity transforms relate the time domain cyclic convolution of the data signal and the channel impulse response to a dyadic convolution of the data signal and the channel impulse response; and wherein applying similarity transforms to the WHT domain spectra of the channel impulse response comprises computing Hadamard products of the similarity transforms and one-dimensional expansions of the WHT domain spectra of the channel impulse response.