  Opportunistic analysis has traditionally relied on independence assumptions
that break down in many interesting and useful network topologies. This paper
develops techniques that expand opportunistic analysis to a broader class of
networks, proposes new opportunistic methods for several network geometries,
and analyzes them in the high-SNR regime. For each of the geometries studied in
the paper, we analyze the opportunistic DMT of several relay protocols,
including amplify-and-forward, decode-and-forward, compress-and-forward,
non-orthogonal amplify-forward, and dynamic decode-forward. Among the
highlights of the results: in a variety of multi-user single-relay networks,
simple selection strategies are developed and shown to be DMT-optimal. It is
shown that compress-forward relaying achieves the DMT upper bound in the
opportunistic multiple-access relay channel as well as in the opportunistic nxn
user network with relay. Other protocols, e.g. dynamic decode-forward, are
shown to be near optimal in several cases. Finite-precision feedback is
analyzed for the opportunistic multiple-access relay channel, the opportunistic
broadcast relay channel, and the opportunistic gateway channel, and is shown to
be almost as good as full channel state information.
