In this paper, we prove that, in MIMO system affected by flat fading, when the channel is unknown at the trans mitter and known at the receiver side, a space-time code does no induce any information loss, regardless of the channel realization if and only if it is a Trace-Orthogonal Design (TOD). Then, in the effort to find a good tradeoff between performance and receiver complexity, we show that, when symbols are carved from a QPSK constellation, the suboptimal detector composed of a linear MMSE estimator followed by hard decision, achieves the minimum bit error rate (BER), if and only if the encoding matrices are, UP to a multiplicative constant, full rank partial isometrics. Such matrices constitute what we term a Unitary Trace-Orthogonal Design (UTOD). Finally, we propose a procedure for the synthesis of TODs which, moreover, can guarantee full diversity when information symbols are carved from constellations composed of algebraic numbers, i.e., for (practically) any conceivable complex constellation.
Trace-orthogonal space-time coding / Antonio, Fasano; Barbarossa, Sergio. - In: IEEE TRANSACTIONS ON SIGNAL PROCESSING. - ISSN 1053-587X. - 56:5(2008), pp. 2017-2034. [10.1109/tsp.2007.909225]
Trace-orthogonal space-time coding
BARBAROSSA, Sergio
2008
Abstract
In this paper, we prove that, in MIMO system affected by flat fading, when the channel is unknown at the trans mitter and known at the receiver side, a space-time code does no induce any information loss, regardless of the channel realization if and only if it is a Trace-Orthogonal Design (TOD). Then, in the effort to find a good tradeoff between performance and receiver complexity, we show that, when symbols are carved from a QPSK constellation, the suboptimal detector composed of a linear MMSE estimator followed by hard decision, achieves the minimum bit error rate (BER), if and only if the encoding matrices are, UP to a multiplicative constant, full rank partial isometrics. Such matrices constitute what we term a Unitary Trace-Orthogonal Design (UTOD). Finally, we propose a procedure for the synthesis of TODs which, moreover, can guarantee full diversity when information symbols are carved from constellations composed of algebraic numbers, i.e., for (practically) any conceivable complex constellation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.