Diversity-multiplexing tradeoff of MIMO linear precoding

This work characterizes the diversity-multiplexing tradeoff (DMT) of MIMO systems with linear precoders. We analyze the cases of zero-forcing (ZF), regularized ZF (RZF), matched filtering and Wiener filtering precoded MIMO systems. We show that MIMO systems with ZF precoding achieve the same DMT as that of MIMO systems with ZF equalizer. When a regularized ZF (RZF) or Matched filter (MF) precoder is used, the DMT implies an error floor at all rates. However, we observe that in the fixed rate regime (i.e. zero multiplexing gain) both RZF and the MF precoded systems can sometimes achieve the maximum spatial diversity. When the regularization factor in the RZF precoder is optimized in the MMSE sense, the DMT implies low diversity gain in the fixed rate regime; however the diversity in this regime is function of the spectral efficiency and can be as large as the maximum spatial diversity.