Enhancing the quality of the simple phone call—and setting the stage for 5G Advanced.

T-Mobile was the first U.S. carrier to roll out Wi-Fi Calling for smartphones, allowing users to place calls and send texts when little to no cellular reception is available. Wi-Fi calling was followed by HD Voice to dramatically enhance in-call audio performance.  

Our advanced version of Voice over LTE (VoLTE) technology brought both data and voice onto the same radio layer for faster call connections and data speeds. Finally, we moved voice traffic to the 5G network with Voice over New Radio (VoNR). 

How we made it happen:

Working with our longstanding partners Ericsson, Nokia, Qualcomm, MediaTek, and Cisco, T-Mobile achieved the first low-band VoLTE and VoNR calls. These proofs of concept eliminated the need for a mid-band LTE anchor and helped usher in the standalone core, network slicing, and later 5G Advanced.  

The first low-band SA 5G voice call used Evolved Packet System (EPS) fallback to VoLTE in the interim while the VoNR technology was being fully developed. Our tests for the first low-band VoNR call on a production network proved that standalone and non-standalone (NSA) 5G devices could operate with active sessions at the same time in the same cell.  

Connecting a nation with the high-speed, low-latency performance of 5G.

T-Mobile was the first U.S. carrier to launch a nationwide 5G network. In addition to connecting more people in more places, our nationwide 5G network gained us an early lead in next-generation wireless technology and ushered in more innovative 5G-based applications and services.

How we made it happen:

Carriers had been hyping 5G for years. T-Mobile was the first to offer true, standards-based 5G using clear 600 MHz spectrum. The merger with Sprint and its 2.5 GHz spectrum made 5G multi-spectrum a reality and uniquely positioned us to deliver 5G across the nation.

Switching on the first 5G Standalone network—nationwide.

T-Mobile was the first carrier in the world to stand up a 5G Standalone (SA) network. Unlike 5G Non-Standalone (NSA), 5G SA does not rely on existing 4G core infrastructure and instead uses a dedicated 5G core. 5G’s advances are the result of the network becoming increasingly software defined. This “programmability” of the network offers more flexible service configuration and delivery.

Benefits of the 5G Standalone core:

• Makes possible a whole new level of performance with faster speeds, lower latency, and far more capacity.   

• Paves the way for emerging services and applications like network slicing and 5G channel aggregation.  

• Amplifies the performance of consumer experiences for augmented and virtual reality and real-time translation. 

How we made it happen:

T-Mobile worked with multiple global industry leaders to accomplish a series of standalone 5G world firsts—from the first 5G SA data session between commercial modems from two suppliers on a production network to the first low-band VoNR and ViNR calls. Each of these tests demonstrated the potential of standalone 5G and paved the way to our standalone core as it exists today.  

Our 5G core network coordinates different parts of the access network and connects to the internet and the core networks of other telecom operators. The core’s service-based architecture eliminates the unwieldy signaling approach of the 4G core network. Instead, signaling is processed by interconnected network functions—typically virtual instances—each of which must request authorization to access another’s services.  

T-Mobile's first 5G SA network worked only for our low-band frequencies, improving 5G coverage by 30 percent. Today, the entire network is covered, and we're able to automate the programming of it through a simple command. 

Dedicating slices of the network for custom uses.

Network slicing carves up network resources to create unique, virtualized networks on top of a shared 5G architecture. These secured, distinct slices make it possible for T-Mobile to customize traffic for different services and applications.

Network slicing use cases: 

• T-Priority, the nation’s first network slice for first responders, ensures they get lower latency and faster 5G speeds more consistently, and gives them the highest priority across every 5G band.

• The T-Mobile Secure Access Service Edge (SASE) solution includes the first ever commercial deployment of a network slice with T-Mobile Security Slice, offering businesses and government orgs an extra layer of security and control.

• T-Mobile has successfully used network slicing to run point-of-sale systems that handle millions of dollars of transactions at massive events like the Las Vegas Grand Prix and PGA Championship.

How we made it happen:

Slicing the network is an old concept that’s been missing one key feature: the programmability to assign each slice of network its own characteristics, rules, and logic.  

We recognized that the software-defined architecture of our 5G SA core held the missing piece and brought chipmakers Qualcomm and MediaTek to explore the potential. We relied on our 5G RAN and core partners, Ericsson, Cisco, and Nokia, for the features needed to support slicing. And we brought in vendors like Apple, Google, and Samsung so they could develop the necessary components to support it on consumers’ favorite devices.  

Offering coverage in remote areas where cell towers can’t go.

T-Satellite is solving wireless’ biggest pain point—mobile dead zones. In partnership with Starlink, our T-Satellite solution uses direct-to-cell technology to provide mobile users connectivity in remote areas where siting is impractical, and traditional signals can’t reach. In the future, we could see land-based 5G technologies and satellites working together to provide coverage for users on the move in cars, ships, and planes.

How we made it happen: 

T-Mobile and SpaceX worked together to overcome the technical challenges of bringing satellite connectivity to smartphones. First, breakthroughs in miniaturization and electronics made it possible to integrate wireless RAN technology directly onto the new Starlink V2 Mini satellites.  

By tapping into frequencies typically reserved for ground-based networks—which satellites hadn’t used before—we were able to extend coverage everywhere without modifying the hardware needed to use the service. This innovative strategy ensures our service remains compatible with standard midband spectrum to support a wide range of devices, and even other carriers. 

Innovating for the future, here and now.

3GPP is the global body that sets the standards for how 5G works, and the authority T-Mobile looks to when it’s time to lead the way for other carriers. We blended elements from the 3GPP’s Release 17 and 18 to stand up the first 5G Advanced network—and set a new standard in network capabilities. This next-evolution of 5G networks is driving more intent-based and pervasive experiences using built-in artificial intelligence and automation.

How we made it happen: 

Release 17 focused on enhancements to radio access network (RAN), beamforming, and multiple-input, multiple-output (MIMO). Combining that with the artificial intelligence (AI) and machine learning (ML) standards set in Release 18 allowed us to make 5G Advanced a reality here and now—and brings us all closer to the widespread adoption of AI and ML in consumer and industry applications.

Unlocking an advanced wireless network with and for AI. 

5G Advanced features are paving the way for the rapid development of AI-RAN—and the transformative potential it unlocks. Leading the way, with our partners NVIDIA, Ericsson, and Nokia, we’re designing and driving mobile networks with AI at the center. Soon, AI-RAN enhanced networks will leverage billions of data points to devise algorithms that maximize performance, predict real-time capacity, and support new applications like generative AI and robotics. 

True innovation doesn’t happen in a bubble. T-Mobile has long depended on a partner ecosystem to move wireless forward. And we’re staunch believers in supporting and investing in developer innovation, too.