  In this paper, we investigate relay selection for cooperative
multiple-antenna systems that are equipped with buffers, which increase the
reliability of wireless links. In particular, we present a novel relay
selection technique based on switching and the selection of the best link, that
is named Switched Max-Link. We also introduce a novel relay selection criterion
based on the Maximum Likelihood (ML) principle and the Pairwise Error
Probability (PEP) denoted Maximum Minimum Distance (MMD) that is incorporated
into the proposed Switched Max-Link protocol. We compare the proposed MMD to
the existing Quadratic Norm (QN), in terms of PEP and computational complexity.
Simulations are then employed to evaluate the performance of the proposed and
existing techniques.
