AT&T has been criticized for “confusing” the U.S. market by labeling its advanced 4G network “5G Evolution.” The complaint is that 5G Evolution is not “real 5G.”That requires a bit of explanation, the most important point being that the 5G standard explicitly builds on 4G.
Many observers note that the existence of dense 4G networks featuring using small cells connected using optical fiber reduces the cost of 5G infrastructure. “Operators with existing 4G footprints will be able to leverage their 4G infrastructure for providing 5G services and hence their investment requirement will be relatively less,” said TRAI.
Network Function Virtualization (NFV) and Software Defined Networking (SDN) enable virtual network slices for different vertical markets, and also is an evolution of the core network to support both 4G and 5G.
Massive Multiple Input Multiple Output radios and advanced antenna systems likewise can be part of the transition from 4G to 5G.
In fact, according to 3GPP specifications, 5G will be deployed in two different modes, Non-Standalone (NSA) and Standalone (SA).
In NSA, (5G) NR and (4G) LTE are tightly integrated and connect to either the existing evolved packet core or the 5G NG core. In standalone mode, either 5G NR or 4G LTE radios connect to 5G NG Core.
The point, says India’s TRAI, is that “in order to have speedy deployment of the 5G, initially it is going to be deployed in coexistence with LTE.”