With the rise of modular
system architecture for
distributed satellite systems with multiple
small payloads instead of conventional larger spacecrafts, the efficient characterization of
power budget and available power constraints become even more vital. In order to establish
high data rate downlink com
munications in small satellite applications, use of highly
efficient, non
-
conventional power amplification techniques is going to be a key factor in
future communication systems. The concept of having small, less power consuming and high
data rate transmis
sion system extends to vast number of applications like light weight
Unmanned Aerial Vehicle (UAV) and hand
-
held communication modules etc.
The idea is to study and develop an
adaptive
envelope tracking technique which should be
able to dynamically supply
power to
Radiofreq
uency power amplifier. Consequently,
a
n
optimal control over system power consumption leads
to
enhanced efficiency.
The amplifiers
intended for such systems exhibit nonlinear behavior when it comes to operating at maximum
output power an
d cause distortion in adjacent bands.
Introducing a power supply modulation
block in combination with digital linearization techniques such as DPD
offers considerable
improvement.
Th
is thesis tests a dynamic power supply adaptive shaping technique f
or LTE signals. In
comparison to conventional fixed supply
RF PAs, Envelope Tracking PA has resulted in
improved linearity at the output as well as reduced unwanted power leakage into adjacent
frequency channels.
By imposing an isogain trajectory trough th
e shaping function, we can
optimize the available power for high data rate communications while keeping the
intermodulation distortion
at acceptable levels by considering a tradeoff
between efficiency
and
computational load
