| 摘要 |
A method is disclosed to minimize the mean-square-error of an estimate of an unknown parameter, such as a data symbol transmitted through a channel, such as a WCDMA channel. The method includes steps of (a) replacing a required multiplication of an input signal vector by an inverse covariance matrix, which is one of a total signal covariance matrix or an interference-plus-noise covariance matrix, by linear filtering, wherein directly computed or estimated filter elements of a row or a column of the inverse covariance matrix, corresponding to time instant i, are used as linear filter coefficients; (b) forming a vector g(i) from the filter outputs, the vector g(i) being estimated element by element using the linear filter; and (c) using the vector g(i) in place of a vector that would have been obtained by directly multiplying the signal vector by the inverse covariance matrix. The linear filter w(i) converges or closely converges to a row or column of the required inverse covariance matrix. For the case of the interference-plus-noise covariance matrix, when a desired filter is found through adaptation, the desired filter is used to filter the total signal, including the desired signal, to generate the output vector g(i). The filter outputs generated using either of the total signal covariance matrix or the interference-plus-noise covariance matrix are employed to estimate an unknown parameter through the use of a further filter matched to the pulse shape of the unknown parameter carried by the input signal, where the further filter is a RAKE receiver that performs multipath combining at a chip level and single code correlation, or a RAKE receiver that performs despreading using a code correlator bank, and multipath combining at the symbol level using the correlator outputs.
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