NTT DoCoMo Inc. has disclosed its next-generation mobile communication system, "Super 3G," at CEATEC Japan 2007 and demonstrated communictions using 4 x 4 MIMO transmission. This was the system's public debut.
The company demonstrated 12 video streams being delivered at roughly 15 Mbps per stream and interactive communications between a pair of camcorders at the same time using the system's frequency band.
Fujitsu Ltd. manufactured this Super 3G system. Despite the use of the 20 MHz narrow band, data rates using 4 x 4 MIMO transmission reached approximately 200 Mbps when uploading and 25 Mbps when downloading.
"Our goal is to achieve a maximum rate of 300 Mbps," NTT DoCoMo said. Modulation technologies are OFDMA for downloading and "DFT (discrete Fourier transform)-spread OFDM" for uploading. DFT-spread OFDM, a form of single carrier modulation technology, suppresses "the peak-to-average power ratio (PAPR)," which becomes high and therefore has been regarded as a challenge that OFDM has to overcome.
Without using actual radio, DoCoMo connected the system with wires, adding phasing and some other effects for the demonstration. Regarding the commercialization schedule, "We are not sure when we can start offering the service, but we aim to complete the technology in around 2010" said DoCoMo.