Even if 5G will–if successful–be a revolution in mobile business models, its technological foundations will be an evolution from 4G. That is one of the paradoxes of 5G: it will, in many ways, be a technological evolution from 4G, but its success as a platform will be quite revolutionary.
The “5G is an evolution from 4G” trend is obvious, such as the improvement in 4G network performance. Perhaps the most-obvious developments are faster speeds, as channels are aggregated (across licensed bands as well as using unlicensed spectrum).
Where once 4G LTE speeds topped out around 75 Mbps, for example, speeds now are heading for a gigabit.
The latest advance comes in the latency area. Working with Nokia, SK Telecom has demonstrated reduced latency between an LTE handset and base station from 25 milliseconds to 2 ms.
The latency improvements illustrate another trend, namely the evolution of advanced 4G technologies to underpin 5G. Latency performance, spectrum aggregation, use of small cells and multiple input multiple output (MIMO) radios, as well as ways to use the 4G signaling network to support 5G air interfaces are examples.
The latency between the handset and base station in the existing LTE environment is around 25 ms, SK Telecom notes. Lower latency matters for some internet of things applications, especially autonomous vehicles and telemedicine.
Skeptics might argue that the ability to support 5G levels of lower latency means 5G is not needed. Optimists will say the test proves 5G latency goals can be hit, removing one more development obstacle.
At 25 ms latency, a self-driving vehicle running at 150 kilometers per hour (okay, most of us are never in vehicles moving that fast), the vehicle travels about one meter after receiving a “decelerate” message, before it actually begins to decelerate.
At 2 ms latency, the vehicle moves only 8 centimeters before it begins to slow down, which will significantly enhance the overall safety in autonomous driving.
| Speed | Latency(Handset-Base station) | |
| 2G | 14.4kbps ~ 64kbps | 300 ~ 1000ms |
| 3G | 144kbps ~ 14.4Mbps | 50 ~ 100ms |
| 4G | 75Mbps ~ | 25ms or lower |
| 5G | 20Gbps ~ | 1ms or lower |
Source: Nokia
