Novel Transmit Antenna Selection Schemes with Reduced Channel Feedback Rate Requirement

In this paper, we propose three different transmit antenna selection schemes with reduced feedback requirement compared with the conventional scheme. In Scheme 1, all the Lt available transmit antennas are divided as equally as possible into two groups. The best single antenna within each group is selected. In Scheme 2, only the best one among Lt antennas is made known to the transmitter, and the other one is selected at random. Scheme 3 is for even Lt, and Lt antennas are divided into multiple subsets each consisting of two adjacent antennas, among which the best subset is selected. Analytical performances of these three schemes with the Alamouti space-time block code (STBC) are derived for flat Rayleigh fading channels. The asymptotic signal-to-noise ratio (SNR) loss of each proposed scheme relative to the conventional transmit antenna selection scheme is quantified. Together with the reduction in feedback requirement, the relative merit of each proposed scheme is delineated. In general, all of the three schemes provide a good trade-off between error performance and feedback requirement. And the application scenario for each scheme is also identified. The results in this paper provide guidance for the design of transmit antenna selection systems with various feedback channel bandwidths, different requirements for quality of service, and specific antenna configuration.