  In this paper, we combine communication-theoretic laws with known,
practically verified results from circuit theory. As a result, we obtain
closed-form theoretical expressions linking fundamental system design and
environment parameters with the power consumption of analog front ends for
communication receivers. This collection of scaling laws and bounds is meant to
serve as a theoretical reference for practical low power front end design. In
one set of results, we first find that the front end power consumption scales
at least as SNDR^3/2 if environment parameters (fading and blocker levels) are
static. The obtained scaling law is subsequently used to derive relations
between front end power consumption and several other important communication
system parameters, namely, digital modulation constellation size, symbol error
probability, error control coding gain and coding rate. Such relations, in
turn, can be used when deciding which system design strategies to adopt for
low-power applications. For example, if error control coding is employed, the
most energy-efficient strategy for the entire receiver is to use codes with
moderate coding gain and simple decoding algorithms, such as convolutional
codes. In another collection of results, we find how front end power scales
with environment parameters if the performance is kept constant. This yields
bounds on average power reduction of receivers that adapt to the communication
environment. For instance, if a receiver front end adapts to fading
fluctuations while keeping the performance above some given minimum
requirement, power can theoretically be reduced at least 20x compared to a
non-adaptive front end.
