The application is concerned with decoding a signal sent from a plurality of transmit antennae and received by at least one antenna, the signal comprising codewords having a finite plurality of states and associated transitions and having been modified by respective channel responses for each transmit path, wherein at the decoder a set of estimated codewords and associated channel responses is derived and trellis decoding techniques are employed using the received signal and the derived estimates. The coding is performed by a coding machine operating as a state machine having a series of allowable transitions between states. - The method comprises determining an initial estimate for said set of channel responses and selecting an assumed initial state of said coding machine; extrapolating from said initial estimate and state using said received signal to determine a set of estimated transmitted codewords and associated sets of channel responses, each estimated codeword having an associated estimated set of channel responses; and determining an estimated input data symbol sequence from said set of estimated transmitted codewords to decode said received signal. The extrapolation comprises a plurality of iterations, each iteration comprising establishing a set of allowed transitions from each possible state of said coding machine at a said iteration to each allowed new state of said coding machine for a next iteration; selecting, for each allowed new state of said coding machine with a plurality of allowed transitions to the new state, one of said plurality of transitions by estimating a set of channel responses for each said allowed transition and comparing, for each said allowed transition, said received signal to a codeword associated with the transition modified by said estimated set of channel responses associated with the transition; and then updating the estimated set of channel responses associated with the selected transition using said received signal.
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