Overview
The 3GPP Long Term Evolution (LTE) initiative is
intended to provide a framework for the evolu-
tion of 3G toward a high-data-rate, low-latency
and packet-optimized radio-access technology.
Its aim is to achieve a peak downlink cell data
rate of greater than 100 Mbps and an increase
in capacity of three to ? ve times compared with
HSDPA (in the same bandwidth), with latency
as low as 20 ms. While LTE has the potential
to enhance 3G networks and enable signi? cant
new service opportunities in mobile TV and
video, achieving success in consumer-enabled
devices will not be easy. Among other things, it
will require the engineer to pay close attention
to the power ampli? er (PA); a component
which plays a key role in the LTE transmitter’s
RF front-end. The PA contributes signi? cantly
to handset power consumption and as an
active device, exhibits nonlinear behavior which
can be problematic. LTE’s evolved Node B
(eNB) power ampli? er faces a similar problem
and is compounded by the fact that it can be
multi-carrier or even mixed-carrier. Optimal
LTE system performance demands that the PA
be both highly ef? cient and linear. Accurately
testing the PA during design and optimization
provides one means of achieving this goal.