Field trial of space-time equalizer and delay diversity transmission in uplink for TDMA mobile communication

Space-time (ST) equalizer and delay diversity transmission (DDT) were field tested in uplink for a time-division multiple-access mobile communication system. The ST equalizer used a cascade connection of constrained array processors and branch-metric-combining (BMC) maximum-likelihood sequence estimation which was designed to provide both space- and path-diversity gains from first-arrival and one-symbol-delay paths while suppressing excessive intersymbol interference. DDT with two antennas was used for the mobile transmitter to ensure sufficient path diversity at the ST equalizer in a small-delay-spread environment. Test results showed that the ST equalizer bit error rate (BER) was significantly better than an ST equalizer without BMC and a single array processor for both micro- and macrocell environments. Furthermore, the ST equalizer BER with DDT was better than that without DDT for the microcell environment.