Turbo equalisation

Abstract

A receiver () for receiving for receiving encoded data transmitted simultaneously as a plurality of M different sequences of transmitted symbols from different transmit antennas using a plurality of m modulation levels, where M and m are integers and each of the transmitted symbols represents a plurality of bits of the encoded data, comprises a demodulator () arranged to provide N received symbol combinations by receiving at a plurality of N receive antennas (), where N is an integer, the plurality of M different sequences of transmitted symbols, wherein each received symbol combination comprises M simultaneously received ones of the transmitted symbols. An equalizer () is arranged to generate from the N received symbol combinations M pre-processed signals by performing interference cancellation, in which interference cancellation a different symbol of the respective received symbol combination is a wanted signal and the other symbols of the respective received symbol combination are interfering signals. The equalizer () is also arranged to generate from each of the M pre-processed signals a list of up to m initial candidate symbol combinations by, for each of the up to m initial candidate symbol combinations, selecting a first initial symbol indicative of a different one of the m modulation levels and selecting M−1 further initial symbols. The equalizer () is further arranged to generate from the lists of initial candidate symbol combinations an initial estimate of the transmitted symbols. A decoder () is arranged to decode bits represented by the initial estimate of the transmitted symbols.