Block diagonalisation-based multiuser multiple input multiple output-aided downlink relaying

A novel block diagonalisation (BD)-based Multiuser multiple input multiple output (MU-MIMO)-aided relaying scheme is proposed for downlink transmissions, which does not require any channel state information at the base station (BS) and decomposes a MU-MIMO-aided relaying system into several parallel single-user MIMO-assisted relaying schemes. Furthermore, based on the proposed algorithm the optimal linear processing matrix designed for the maximum achievable capacity is derived, which significantly outperforms the so-called naive weighting matrix.