Affine Projection Decoders in Uplink of MU-MIMO System and Their Performances

For uplink of Multiuser (MU) Multiple-Input, Multiple-Output (MIMO) system with M receive antennas at base station and one transmit antenna at each user, in this paper, new decoders, namely affine projection decoders, are proposed. Furthermore, detailed analyses on performance of the decoders are given. These show that, for any integer k, 1 <= k <= K (K is the number of users), there is an affine projection decoder such that its diversity order is M - K + k, while its decoding complexity is higher than linear decoders (if k > 1), and lower than Maximum-Likelihood (ML) decoder (if k < K). Hence, any diversity order between M - K + 1, which is the diversity order of linear decoders and M, which is one of ML decoder, can be realized, while decoding complexity is also increased with the increase of the diversity order.