Diversity-multiplexing tradeoff in MIMO relay channels for a broad class of fading distributions

Diversity multiplexing tradeoff (DMT) in MIMO relay channels, where the transmitter and receiver are equipped with multiple antennas and the relay with a single one, is derived for a broad class of fading distributions, including, as special cases, non-identical, spatially correlated, and non-zero mean channels. It is shown that the DMT does not depend on a particular fading distribution, but rather on its polynomial behavior near zero. The DMT turns out to be the same for the simple "amplify-and-forward" mode and more complicated "decode-and-forward" relaying (with capacity achieving codes), i.e. the full processing capability at the relay does not help to improve the DMT.