Summary: 3112 IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 48, NO. 12, DECEMBER 2002
Existence and Construction of Noncoherent Unitary
Vahid Tarokh, Member, IEEE, and Il-Min Kim
Dedicated to D. James E. Mazo on the Occasion of His Retirement
Abstract--We consider transmission using transmit and reception
using receive antennas in a wireless environment assuming that
neither the transmitter nor the receiver knows the channel coefficients.
For the scenario that the transmission employs noncoherent
unitary spacetime codes and for a block-fading channel model where
the channel is static during channel uses and varies from channel
uses to the other, we establish the bound min( ) on the
diversity advantage provided by the code. In order to show that the
requirement min( ) cannot be relaxed, for any given ,
, , and min( ), we then construct unitary
spacetime codes of rate that guarantee diversity advantage . Two
constructions are given that are also amenable to simple encoding and
noncoherent maximum-likelihood (ML) decoding algorithms.
Index Terms--Diversity, multiple antennas, noncoherent, spacetime
codes, wireless communications.