摘要 |
System performance in wireless communication is improved by increasing diversity in time, space and frequency. In OFDM-based MIMO systems in which the number of antennas M is greater then the number of simultaneously transmitted OFDM symbols N, circulation transmissions according to the present invention improve signal diversity. In symbol-based circulation transmission, N antennas are chosen from the M available antennas to transmit the N OFDM symbols. In subcarrier-based circulation transmission, M output OFDM symbols are composed from the QAM-mappled samples of the N input OFDM symbols. These M output OFDM symbols are then transmitted from the M antennas simultaneously. |