STANFORD UNIVERSITY
EE 350 RADIOSCIENCE SEMINAR
Professor Umran S. Inan
Winter 1998-99
Date: Wednesday, January 13, 1999
Time: 4:15-5:30 PM; Refreshments at 4:00 PM
Location:
** Building 260, Rm. 113 **
**(please note new location)**
Some Key Aspects of Solar-Terrestrial Coupling
Prof. Andrea Goldsmith
Electrical Engineering, Stanford University
Abstract
The spectral efficiency of flat-fading channels can be significantly increased
when the transmitter adapts its power and rate to the channel variation. We
therefore propose an adaptive MQAM modulation technique which optimally adapts
its power and rate to maximize spectral efficiency. The resulting efficiency
is calculated and compared to the theoretical maximum. Additional coding gain
can be obtained by superimposing a trellis or turbo code on top of the
adaptive modulation. Our modulation is sensitive to estimation error and
delay, and we quantify the degradation in performance resulting from these
effects. We also show how adaptive modulation can be used in narrowband and
CDMA multimedia systems to meet different data rate and BER requirements.
We conclude the talk by applying adaptive modulation to a TDMA cellular
system. We determine the resulting area spectral efficiency (bps/Hz/unit area)
for various power adaptation algorithms, propagation conditions, reuse
factors, and cell sizes.