Summary: IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 54, NO. 1, JANUARY 2008 33
Diversity Embedded Space­Time Codes
Suhas N. Diggavi, Member, IEEE, A. Robert Calderbank, Fellow, IEEE, Sanket Dusad, and
Naofal Al-Dhahir, Fellow, IEEE
Abstract--Rate and diversity impose a fundamental tradeoff in
wireless communication. High-rate space­time codes come at a
cost of lower reliability (diversity), and high reliability (diversity)
implies a lower rate. However, wireless networks need to support
applications with very different quality-of-service (QoS) require-
ments, and it is natural to ask what characteristics should be
built into the physical layer link in order to accommodate them.
In this paper, we design high-rate space­time codes that have a
high-diversity code embedded within them. This allows a form
of communication where the high-rate code opportunistically
takes advantage of good channel realizations while the embedded
high-diversity code provides guarantees that at least part of the
information is received reliably. We provide constructions of linear
and nonlinear codes for a fixed transmit alphabet constraint. The
nonlinear constructions are a natural generalization to wireless
channels of multilevel codes developed for the additive white

Source: Al-Dhahir, Naofal - Department of Electrical Engineering, University of Texas at Dallas

Collections: Engineering