Method of and apparatus for digital radio signal reception

Abstract

A receiver is described, for instance for GSM systems, wherein a plurality of digital signals each comprising a training sequence (x,(t)) usable to generate an estimation of the transmission channel are received in diversity (A.,. . . A.N) in the form of a plurality of replicas (,.N) each comprising a respective replica of the training sequence. The received digital signal is subjected to a delaying action thereby obtaining a plurality of versions of such signal, each comprising a respective set of signal replicas. Each version is subjected to a respective filtering action (,.N) independently from the other versions, by employing a respective first set of filtering coefficients (w*,. . . w*,. . . w*,) obtained starting from a respective initial set of filtering coefficients. This respective initial set is obtained by performing, for each replica of the received signal, a filtering action exploiting a respective second set of filtering coefficients identified as a signal (u(t)) able to generate, by convolution (u(t)*x,(t)) with the training sequence, a unitary function &dgr;(t) on a given time window, preferably on one bit. The filtering coefficients of the first set are derived starting from said initial set of filtering coefficients through an MMSE adaptation, preferably with an initial rapid convergence phase of the RLS type followed by an optimisation phase of the LMS type.