A blind multi-user MIMO transceiver using code modulation in a multipath context

A deterministic blind equalizer for multiuser multiple input multiple output systems (multiuser MIMO systems, i.e. multiuser systems where both the base station and the users have multiple antennas) with space-only coding that performs direct symbol estimation was proposed by Leus et al. (2001). The proposed algorithm was initially designed to cope with flat-fading transmission channels and was then extended to the case where multipath effects arise, at the cost of a severe increase in computational complexity. In this paper, we propose an extension of the initial algorithm in a wideband context with severe multipath effects, maintaining the computational complexity at reasonable levels by the use of DMT (discrete multi tone, also called OFDM, orthogonal frequency division modulation) and related block transmission techniques that use a cyclic prefix. The results show that the proposed blind equalization method performs efficient noise reduction and MUI (multiuser interference) and ISI (intersymbol interference) cancellation whilst the computational complexity is reduced.