Single- and multicarrier transmission in up- and downlink scenarios with intersymbol interference: a comparison

Upand downlink transmission over MIMO channels where the transmission paths exhibit intersymbol interference are studied. Equalisation schemes for multipoint-topoint scenarios (multiple access problem, uplink) and precoding schemes for point-to-multipoint scenarios (broadcast channel, downlink) are investigated. In particular, singlecarrier modulation employing decision-feedback equalisation/precoding, multicarrier modulation employing BLAST/precoding per carrier, and frequency-division multiplexing in disjoint frequency bands are considered. The rate regions, i.e., the region of admissible rates of the users, for these approaches are given and compared. It is shown, that despite singleand multicarrier transmission can achieve the same sum rate, in each case MIMO OFDM offers the largest rate region. The results are illustrated via numerical examples.