High bit rates for 3G and beyond using MIMO channels

This paper studies the applicability of selected high rate open-loop space-time codes and closed-loop beamforming concepts for future wireless systems, such as WCDMA/HSDPA. Several spectrally efficient space-time codes are evaluated and their performance is compared to related closed-loop concepts, where a feedback link from the receiver is used to aid (downlink) beamforming. The comparison is based on schemes that attain 4bps/Hz spectral efficiency, where either two parallel QPSK streams or a single 16-QAM stream is transmitted using up to four transmit antennas, and one or two receive antennas.