T-Mobile is once again ahead of the pack when it comes to pure standalone 5G in the United States.

Following its 600MHz nationwide 5G network launch in August 2020, T-Mobile has now converted its 2.5GHz mid-band network—which the company markets as “ultra-capacity”—to run on a 5G core. T-Mobile said that this network, which launched in November 2022, covers more than 250 million people in the U.S., and puts the carrier ahead on standalone 5G in the U.S. 

Meanwhile, carriers worldwide are just starting to move to standalone 5G. The 3rd Generation Partnership Project (3GPP) completed its initial standalone 5G specification in September 2018. Yet AT&T, Verizon and most other major mobile network operators (MNOs) worldwide still rely on a non-standalone (NSA) 5G network for their commercial 5G services.

Verizon has only recently started to move commercial traffic onto its 5G standalone core. AT&T says it is moving customers towards standalone 5G in stages. Both operators use an NSA 5G radio network connected to a 4G core network for much of their 5G service.

In the past, an NSA was the only way to deploy a 5G network when the standard first started to roll out in 2019 and 2020. An NSA 5G network is also cheaper to deploy since it uses an existing 4G core.

Some of the best benefits of 5G, however, are only available when a network is purely 5G.

“Standalone 5G requires software updates in the Radio Access Network and a 5G Core Network, as well as a sufficient amount of spectrum dedicated to 5G and network optimization,” a T-Mobile spokesperson said in an email reply to EE Times’ questions.

T-Mobile is starting its mid-band standalone adventure by bringing carrier aggregation to its network, which involves assigning several radio channels to a user on the 5G service. These frequency blocks are known as carrier channels.  

“We are leveraging 5G carrier aggregation on our standalone 5G network,” the T-Mobile spokesperson said. “Currently, we’re aggregating two channels of 2.5 GHz in places, as well as 2.5 GHz + 600 MHz.” The MNO has also started to combine two or more separate channels of 2.5GHz with a tranche of 1900MHz spectrum.

The aim of this is to increase 5G download speeds for users. T-Mobile said that speeds will vary, depending on the frequency blocks used. The carrier noted, however, that in recent three-band tests, the aggregation has produced peak speeds topping 3 Gbps. 

Pure 5G critical to network slicing

One of the main advantages that standalone 5G enables beyond NSA is network slicing, which enables an MNO to create virtual end-to-end sections on a physical network that can have service level agreements and other characteristics that cater to a specific subscriber base. 

Since 5G first camecommercial use, vendors and operators have been crowing about the benefits of network slicing. The technology, however, cannot be delivered without a pure 5G standalone network.  

“We are still in the early stages of 5G network slicing implementation,” the T-Mobile spokesperson said, adding that network slicing “expands the market for critical enterprise applications that may require a different level or capability than other applications, such as remote operations, robotics and automation.”

MNOs remain cautious about standalone goals

While T-Mobile has a head start on getting its standalone networks up and running, Verizon said that in October 2022 it started moving traffic onto its standalone core following testing and friendly trials. The company hasn’t given any further details about how many users are covered by its standalone network. 

AT&T is also cautious about giving too much away about its standalone plans. “AT&T continues to make progress with our standalone 5G commercial launch,” the company said in prepared remarks. “We have begun to gradually migrate users to the core in stages throughout 2022 and2023.”