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.
Highlights
I T is well-known that multiple-input multiple-output (MIMO) wireless communications systems have increased capacity [1]–[3] if the number of receive antennas is at least as large as the number of transmit antennas
In this paper we have considered a general framework for transmit antenna selection with space-time block codes
In our general framework, based on the instantaneous channel conditions, the transmitter chooses a space-time block codes (STBCs) and a weighting matrix for transmission aiming at minimizing the error probability
Summary
I T is well-known that multiple-input multiple-output (MIMO) wireless communications systems have increased capacity [1]–[3] if the number of receive antennas is at least as large as the number of transmit antennas. Alamouti’s scheme called the researchers’ attention because of its simplicity and its low decoding complexity; maximum likelihood decoding is simplified because of the orthogonality imposed on the codewords This technique has been generalized through the concept of orthogonal designs to an arbitrary number of transmit antennas by Tarokh et al [5], who coined the name space-time block codes (STBCs). In [6], an OSTBC is used along with the optimal subset of transmit antennas, which is the one whose associated subchannel matrix has the largest Frobenius norm This translates to maximizing the instantaneous received signal-to-noise ratio (SNR) This scheme applies to any OSTBC, the authors have focused on transmit antenna selection with Alamouti (TAS/A), where the Alamouti code [4] is used along with the optimal pair of antennas.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
