Field experiments on dual-polarized MIMO transmission with ultra-multilevel OFDM signals toward digital terrestrial broadcasting for the next generation

We developed a transmission system using ultra-multilevel orthogonal frequency division multiplexing (OFDM) technology and dual-polarized multiple-input multiple-output (MIMO) technology for experimental purposes based on the conventional digital terrestrial broadcasting signal format, ISDB-T. We conducted field experiments at 27 reception points around NHK Science & Technology Research Laboratories (STRL) using an experimental transmitter installed at NHK STRL. As a result, we obtained quasi error free (QEF) operation in MIMO -OFDM transmission whose carrier modulation scheme was 4096QAM. We found that the average required field strength was about 60 dBμV/m for 4096QAM in the field experiments and there was a large difference in field strength at some reception points between both polarized signals that deteriorated the bit error rate characteristics, even if the average field strength was sufficiently high.