'Institute of Electrical and Electronics Engineers (IEEE)'
Doi
Abstract
Cataloged from PDF version of article.The design of space–time signals for noncoherent
block-fading channels where the channel state information is
not known a priori at the transmitter and the receiver is considered.
In particular, a new algebraic formulation for the diversity
advantage design criterion is developed. The new criterion encompasses,
as a special case, the well-known diversity advantage
for unitary space–time signals and, more importantly, applies to
arbitrary signaling schemes and arbitrary channel distributions.
This criterion is used to establish the optimal diversity-versus-rate
tradeoff for training based schemes in block-fading channels.
Our results are then specialized to the class of affine space–time
signals which allows for a low complexity decoder. Within this
class, space–time constellations based on the threaded algebraic
space–time (TAST) architecture are considered. These constellations
achieve the optimal diversity-versus-rate tradeoff over
noncoherent block-fading channels and outperform previously
proposed codes in the considered scenarios as demonstrated by
the numerical results. Using the analytical and numerical results
developed in this paper, nonunitary space–time codes are argued
to offer certain advantages in block-fading channels where the appropriate
use of coherent space–time codes is shown to offer a very
efficient solution to the noncoherent space–time communication
paradigm