MIMO decoder with QR decomposition performed before and after lattice reduction, using a feedback arrangement

摘要

A lattice reduction aided MIMO detector is disclosed which is operable to detect information in a packet based signal comprising a header and one or more data symbols. The detector comprises a pre-processing section 12 operable to derive channel decoding information (C, R, P, T on the basis of a channel estimate H from said header, and a data processing section 14 operable to process said one or more data symbols with reference to said channel decoding information. The pre-processing section comprises QR decomposition means 24 and lattice reduction means 26, wherein an output from the lattice reduction means HT is fed back to the input of the QR decomposition means. Thus the QR decomposition means can be used as a first stage of lattice reduction to, for example, operate on the channel estimate input H to provide an upper triangular matrix R as input to the lattice reduction means. Crucially, the QR decomposition means can also operate on the reduced channel matrix HT to derive channel decoding information such as CORDIC information C based on QH . Fig. 4 is particularly relevant.