  Power talk is a novel concept for communication among units in a Micro Grid
(MG), where information is sent by using power electronics as modems and the
common bus of the MG as a communication medium. The technique is implemented by
modifying the droop control parameters from the primary control level. In this
paper, we consider power talk in a DC MG and introduce a channel model based on
Thevenin equivalent. The result is a channel whose state that can be estimated
by both the transmitter and the receiver. Using this model, we present design
of symbol constellations of arbitrary order and analyze the error probability
performance. Finally, we also show how to design adaptive modulation in the
proposed communication framework, which leads to significant performance
benefits.
