Extended Techniques for Transmit Antenna Selection With STBCs

Abstract

In this paper, we consider transmit antenna selection (TAS) with space-time block codes (STBCs). We consider a general framework for TAS which, besides antenna subset selection, includes the possibility of having more than one STBC to choose from as well as non-uniform power allocation. Also, to limit the number of transmit RF chains, we require that the maximum (row) rank of the STBC matrices have an upper limit. Simple analysis indicate that transmitting uncoded data via the transmit antenna with the largest Frobenius norm, which can be viewed as a particular case of TAS with orthogonal STBC (OSTBC), not only provides full diversity as if all the transmit antennas were used but also has larger signal-to-noise ratio as compared to TAS with any standard OSTBC (like the Alamouti code). This suggests that TAS with non-orthogonal STBCs should be considered, in particular by means of exploiting instantaneous coherence within subsets of antennas. A few TAS schemes are proposed and computer simulations are used to demonstrate their superior error performance.