  This paper investigates the problem of coordinating several agents through
their actions. Although the methodology applies to general scenarios, the
present work focuses on a situation with an asymmetric observation structure
that only involves two agents. More precisely, one of the agents knows the
past, present, and future realizations of a state (the system state) that
affects the common payoff function of the agents; in contrast, the second agent
is assumed either to know the past realizations of the system state or to have
no knowledge of it. In both cases, the second agent has access to some strictly
causal observations of the first agent's actions, which enables the two agents
to coordinate. These scenarios are applied to the problem of distributed power
control; the key idea is that a transmitter may embed information about the
wireless channel state into its transmit power levels so that an observation of
these levels, e.g. the signal-to-interference plus noise ratio, allows the
other transmitter to coordinate its power levels. The main contributions of
this paper are twofold. First, we provide a characterization of the set of
feasible average payoffs when the agents repeatedly take long sequences of
actions and the realizations of the system state are \acs{iid}. Second, we
exploit these results in the context of distributed power control and introduce
the concept of coded power control. We carry out an extensive numerical
analysis of the benefits of coded power control over alternative power control
policies, and highlight a simple yet non-trivial example of a power control
code.
