5G Builds Directly on Advanced 4G

source: Qualcomm

Some observers will argue that the “5G Evolution” networks already launched by AT&T are not really “5G.” You might recall similar arguments back when 4G was first launched, especially since there were two different air interface standards.

The arguments soon enough will be moot. For starters, the name “5G Evolution” is proper, describing investments that all roadmaps show will be foundational for the 5G air interface.

The AT&T 5G Evolution networks feature network upgrades that include LTE-Advanced technologies like 256 QAM, 4x4 MIMO, and 3-way carrier aggregation, all of which also will be used by 5G, at those same locations, but with a 5G air interface.

By the end of 2017, AT&T expects to deploy LTE-License Assisted Access and four-way carrier aggregation in certain areas of 5G Evolution metros. Those features also will be foundational for 5G networks.

Small cells are also an important ingredient on our path to 5G, and AT&T is  installing small cells in Indianapolis. Those small cells use centralized RAN (C-RAN) architecture, allowing engineers to add capacity and improve efficiency for hundreds of cell sites quickly and simultaneously.

source: Qualcomm

C-RAN is a key building block for AT&T’s software-defined network, which in turn is integral to 5G.

The point is that 5G builds on advanced 4G, in a direct way.

When the 3GPP approved a “Non StandAlone” (NSA) version of 5G New Radio (5G NR specification,  the way was cleared for suppliers and mobile operators to deploy a version of 5G radio that uses the existing LTE packet core with a broader array of spectrum resources (legacy 4G and new 5G), including spectrum above 6 GHz, below 6 GHz and including LTE Unlicensed and Wi-Fi resources.

So  5G will use many different spectrum assets, aggregating all those assets (including 4G assets) and in early deployments. The air interface is 5G, but control plane functions and spectrum assets can leverage LTE-Advanced.

That is one way 5G will be introduced by building on existing 4G assets, aggregating LTE-Advanced assets with new spectrum resources, with the newer 5G air interface.