  This paper studies the performance of transmission schemes that have rate
that increases with average SNR while maintaining a fixed outage probability.
This is in contrast to the classical Zheng-Tse diversity-multiplexing tradeoff
(DMT) that focuses on increasing rate and decreasing outage probability. Three
different systems are explored: antenna diversity systems, time/frequency
diversity systems, and automatic repeat request (ARQ) systems. In order to
accurately study performance in the fixed outage setting, it is necesary to go
beyond the coarse, asymptotic multiplexing gain metric. In the case of antenna
diversity and time/frequency diversity, an affine approximation to high SNR
outage capacity (i.e., multiplexing gain plus a power/rate offset) accurately
describes performance and shows the very significant benefits of diversity. ARQ
is also seen to provide a significant performance advantage, but even an affine
approximation to outage capacity is unable to capture this advantage and outage
capacity must be directly studied in the non-asymptotic regime.
