Blind MMSE combining for RAKE receivers

A blind MMSE multipath combining method for RAKE receivers in long-code CDMA systems is proposed. The method uses the data before and after the onset of the desired user´s transmission. It shows that the generalized eigendecomposition of the autocorrelation matrices of the post-RAKE signals in these two intervals gives an MMSE combiner for the desired user signal, without the need of the channel state information. The method does not require precise models of the interference but still offers similar performance as that of the optimal RAKE combiner or even better under certain circumstances. An adaptive algorithm is also developed.