1. An apparatus configured to: generate a set of filter coefficients w from inverting a series of sub-matrices F, each of the sub-matrices of size no greater than 2×2 and representing an element of an approximated correlation matrix C rr for a spread spectrum signal received over a multipath channel, where said sub-matrices are each a block-diagonal matrix with elements taken from an element-wise fast Fourier transform of a column of the approximated correlation matrix; wherein the apparatus is configured to generate the set of filter coefficients by combining, as a matrix multiplication F −1 H (D) m , the inverted sub-matrices F −1 with a fast Fourier transform of channel estimation coefficients h of a channel matrix H, where F −1 represents the inversion of the sub-matrices F; the apparatus further configured to perform an inverse fast Fourier transform on the result of the multiplying to resolve a filter matrix W whose elements w comprise the set of filter coefficients; and the apparatus is further configured, for each k th filter coefficient, to matrix multiply the inverted and fast Fourier transformed columnar elements F ↔ - 1 = [ f 0 , 0 ⁡ ( k ) f 0 , 1 ⁡ ( k ) f 1 , 0 ⁡ ( k ) f 1 , 1 ⁡ ( k ) ] - 1 with a combination {umlaut over (Γ)} k =[γ 1 (k)γ 2 (k)] of the k th elements of the channel coefficients h in the Fourier transformed channel matrix H.