  Backscatter communication is a hot candidate for future IoT systems. It
offers the possibility for connectivity with tiny amounts of energy that can be
easily obtained from energy harvesting. This is possible as backscatter devices
do not actively transmit electromagnetic waves. Instead they only reflect
existing electromagnetic waves by changing the antenna load. This fact leads to
significant differences compared to classical communication wrt. the modulation
schemes and achievable data rates. However, to our best knowledge nobody has so
far systematically analyzed the achievable data rates and transmit ranges for
different parameter configurations. Within this paper we derive theoretical
bounds for backscatter communications based on classical information theory. We
then use these bounds to analyze how different parameters - e.g. the distance,
the frequency, or the transmit power - affect the achievable data rates. The
bounds are derived for mono-static configuration, as well as for bi-static
configurations. This allows feasibility analyses for different use-cases that
are currently discussed in 3GPP and IEEE 802.
