Lattice-reduction-aided receivers for MIMO-OFDM in spatial multiplexing systems

Orthogonal Frequency Division Multiplexing (OFDM) significantly reduces receiver complexity in wireless systems with multipath propagation and therefore has recently been proposed for use in wireless broadband multi-antenna (MIMO) systems. The performance of the maximum likelihood(ML) detector in MIMO-OFDM system is optimal, however, its complexity is prohibitive. A number of other detectors, both linear and non-linear, may offer substantially lower complexity, however, their performance is significantly worse. This paper uses a class of lattice-reduction-aided (LRA) receivers for MIMO-OFDM systems with an arbitrary number of antennas that can achieve near maximum likelihood detector performance with low complexity. Performance comparisons between the LRA receiver and other popular receivers, including linear receivers and V-BLAST in both independent and correlated channels, are provided. It will be shown that the performance of the LRA receiver is superior to that achieved by sub-optimal detection methods, especially when the channel is correlated.