NTT Docomo, Japan’s leading mobile operator, in a joint outdoor experiment conducted recently with the Tokyo Institute of Technology succeeded in the world’s first packet transmission uplink rate of approximately 10Gb/s. The test, which is expected to help pave the way for future super-high-bit-rate mobile communications, took place in Ishigaki City of Okinawa prefecture, Japan.
In the experiment, a 400MHz bandwidth in the 11GHz spectrum was transmitted from a mobile station moving at approximately 9KM/h. Multiple-input multiple-output (MIMO) modules were used to spatially multiplex different data streams using 8 transmitting antennas and 16 receiving antennas on the same frequency.
In light of the squeeze on remaining frequencies as mobile data traffic continues to increase, NTT Docomo aims to achieve a transmission speed of more than 10Gb/s using super-high-frequency bands exceeding 5GHz. Such high frequencies have been difficult to use for mobile networks due to the limited distances their waves are able to travel, especially along indirect paths such as around buildings. This is why more robust lower-frequency waves have been the preferred choice for mobile communications systems so far.
The technologies behind the experiment also are applicable to downlink packet transmissions, suggesting that it should be possible to achieve a 10Gb/s downlink, which is one hundred times the 100Mb/s maximum rate of NTT Docomo’s current Xi 4G/LTE service.
NTT Docomo’s research and development initiatives have made news numerous times over the years, including for field tests that achieved downlink maximum speeds of 2.5Gb/s on December 14, 2005 and 5Gb/s on December 14, 2006.