We propose an antenna grouping method that improves the error rate performance of space-time codes in a wide range of mobility environments. The idea is to group symbols to antennas based on limited feedback from the mobile station to utilize all antennas. Our approach requires only two bits of feedback information to achieve better link performance and full rate for a certain four transmit antenna system. Numerical results confirm the bit/frame error gains over the Alamouti-based space-time block code and antenna subset selection strategies.

This letter proposes a method for choosing the best quantized beamforming vector that represents a subcarrier group, for coordinated beamforming in the downlink of multiuser multiple input multiple output-orthogonal frequency division multiplexing systems. The correlation between subcarriers is exploited for reducing the feedforward overhead, while maximizing the sum rate.