NTT DoCoMo lays stage for 10Gbps uplink

Caroline Gabriel/Wireless Watch

Japan's NTT DoCoMo is sometimes outshone by Softbank and SK Telecom in terms of real world deployments of cutting edge technology, but it remains hard to beat in terms of its futuristic R&D. Its latest test saw the world's first uplink packet transmission to reach 10Gbps.

The outdoor experiment was conducted recently with the Tokyo Institute of Technology, and the cellco said it would help to pave the way for future superfast mobile standards in “5G” and beyond.

In the test, which took place in Ishigaki City of Okinawa Prefecture, 400MHz in the 11-GHz band was used to transmit from a terminal moving at nine kilometers and hour. MIMO smart antenna arrays, with eight transmitting and 16 receiving antennas, was used for spatial multiplexing of different data streams.

DoCoMo, like many carriers, is interested in using higher frequency spectrum for mobility as the conventional bands start to reach their capacity.

Spectrum over 5GHz has very short range and poor ability to penetrate walls and obstacles, although very high data rates can be achieved as seen in technologies like 60GHz WiGig. However, emerging antenna and other techniques are starting to make these bands more usable, even for mobility.

The test was run under the auspices of a program sponsored by Japan's Ministry of Internal Affairs and Communications to research the expansion of radio spectrum resources.

The technologies behind DoCoMo's experiment could also be applied to downlink, holding out the prospect of boosting the 100Mbps peak rate of the carrier's current Xi LTE service tenfold. The carrier pointed out that its R&D teams hit download speeds of 2.6-Gbps in experiments as far back as 2005, and reached 5-Gbps in 2006.

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