T-Mobile has begun deploying a new network capability called L4S — Low Latency, Low Loss, Scalable Throughput — as part of its 5G Advanced upgrade. The feature is already active in several U.S. cities, with additional rollouts planned.
T-Mobile says L4S reduces latency, minimizes packet loss, and improves responsiveness even when network demand is high. Those improvements make the technology especially valuable for cloud gaming, extended reality (XR) devices, video conferencing, and remote driving. While wired networks have used L4S methods for some time, this deployment marks one of the first large-scale uses in a wireless carrier network in the United States.
T-Mobile’s chief technology officer, John Saw, told The Verge that customers don’t need new handsets or special service plans to benefit from L4S — the optimization is performed on the network side and applies to compatible sessions automatically.
Because T-Mobile’s 5G Advanced network runs on a standalone 5G core rather than legacy 4G cores, the carrier can add features like L4S more readily and layer on additional capabilities over time, such as network slicing. This architecture aims to provide more flexible performance profiles so apps and devices receive the network behavior they require.
Another part of the strategy is sharing near-real-time network telemetry with developers, enabling apps to adapt dynamically to changing conditions for a better end-user experience.
Remote driving gets a boost
T-Mobile demonstrated L4S’s potential in a remote driving trial conducted with Berlin-based Vay. The company reported that remote operators experienced a steady, low-latency connection that felt responsive even in congested coverage areas, helping to reduce the sense of delay when controlling vehicles from a distance.
The carrier also completed XR trials with Qualcomm and Ericsson using a lightweight pair of smart glasses to stream immersive content over an L4S-enabled link. Test participants reported clearer visuals and smoother motion, and fewer symptoms of motion sickness — a common hurdle for XR adoption. These results suggest L4S could help make XR experiences more comfortable and reliable for wider consumer use.
Smoother cloud gaming
Cloud gaming is already benefiting from L4S as well. NVIDIA has added L4S support to its GeForce NOW platform, and T-Mobile reports that players on the network experienced reduced lag and fewer dropped frames, delivering gameplay that felt closer to native console performance.
Video calling in crowded environments such as airports and stadiums is another practical use case. With L4S, the network can adapt in real time to preserve video and audio quality, reducing frozen video and clipped audio. T-Mobile says it has been testing the capability with popular apps including FaceTime.
A step toward programmable networks
T-Mobile positions L4S as a foundational capability for more programmable, application-aware networks. The carrier plans to offer differentiated performance tiers tailored to specific application needs — for instance, prioritizing ultra-low latency for gaming or stable throughput for live production — as part of future service options.
By exposing live network metrics like cell congestion and latency budgets to partners and developers, T-Mobile says applications can be tuned to respond intelligently to network changes in real time, improving reliability and user experience.
L4S is included in the broader 3GPP Release 18 specifications, and T-Mobile intends to incorporate the feature into upcoming enterprise offerings. Although the rollout is ongoing, the company indicates more commercial use cases are approaching readiness.
(Photo by Mika Baumeister)
See also: T-Mobile expands Starlink beta to AT&T and Verizon
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