Korean operator SK Telecom, using a Nokia platform, demonstrated 20.5 Gbps speed over the air, using pre-5G protocols, for the first time, the firms said.
In October 2015, SK Telecom and Nokia showed speeds of 19.1Gbps, using 56 quadrature amplitude modulation (QAM), 8x8 Multiple-Input Multiple-Output (MIMO) transmission and 400 MHz of bandwidth.
SK Telecom also has demonstrated 25 Gbps speeds, using an Ericsson platform.
The tests show that, given enough bandwidth, and trading propagation distance for capacity, while using sophisticated radio technologies and modulation, extraordinary levels of mobile device bandwidth are feasible.
Physics explains the higher capacity of higher-frequency radio waves. Simply, no matter what the modulation method, higher frequencies mean more oscillations in any unit of time. And since each oscillation represents the ability to transmit a symbol state, the more oscillations, the more symbol states can be transmitted, in any unit of time.
Higher-order modulation matters as well, of course. But the foundation is the sheer increase in possible symbol states made possible by higher oscillation rates.
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