  We introduce a novel communication strategy for DC Micro Grids (MGs), termed
power talk, in which the devices communicate by modulating the power levels in
the DC bus. The information is transmitted by varying the parameters that the
MG units use to control the level of the common bus voltage, while it is
received by processing the bus measurements that units perform. This
communication is challenged by the fact that the voltage level is subject to
random disturbances, as the state of the MG changes with random load
variations. We develop a corresponding communication model and address the
random voltage fluctuations by using coding strategies that transform the MG
into some well-known communication channels. The performance analysis shows
that it is possible to mitigate the random voltage level variations and
communicate reliably over the MG bus.
