This capability reduce latency or delay, resulting in an improved real-time experience when using immersive applications. It cuts down on lag, making the network faster, while maintaining high throughput, or the amount of data transmitted.
T-Mobile began its 5G deployment with a 5G Standalone (5G SA) network, which is purpose-built for 5G workstreams and doesn’t piggyback on 4G infrastructure. Most other carriers still rely on 4G cores.
This not only resulted in better speeds and greater capacity, but also allowed the company to launch 5G Advanced, which is an important step in 5G technology. This new category of 5G enables better network performance.
Improving the performance of apps where latency can undermine experience
L4S is a part of 5G Advanced. It improves responsiveness and minimizes packet loss or the loss of small data units. This is crucial for use cases where response time can make or break the experience, such as when gaming or attending an online meeting. More importantly, it can be potentially life-saving in scenarios where every millisecond counts, such as remote driving. L4S isn’t a new tech, but T-Mobile is the first company to use it in wireless. It allows T-Mobile‘s 5G network to be more proactive, which is incredibly important for time-critical applications like remote driving, for which the carrier has partnered with the Berlin-based Vay. The company develops remote driving technology, operating cars from different locations.
Implementation of L4S will also allow for the fine-tuning of other experiences, such as Extended Reality (XR) and cloud gaming. T-Mobile notes that XR has the potential to change how we work and play, but it has been held back by jitter and delays. The company has partnered with Qualcomm and Ericsson to test the performance of slim smart glasses with L4S enabled. The result was clear visuals, better frame delivery or data transmission, and reduced motion sickness. T-Mobile concluded that L4S can help take XR mainstream.
L4S can also improve cloud gaming by minimising interruptions. T-Mobile says NVIDIA has already enabled L4S support in GeForce NOW to reduce latency and packet loss during gameplay. This, along with T-Mobile’s 5G Advanced network, should allow for a console-level experience when cloud gaming, even during network congestion.
The tech will also improve the quality of online meetings and calls by dynamically adjusting for network congestion. This will reduce stutters, frozen frames, and distorted audio.
L4S will be foundational to T-Mobile‘s network slicing framework. It will also enable the network to make smarter decisions and offer customized performance tiers for XR, gaming, video, and other latency-sensitive use cases.
The company also plans to bring the capabilities to enterprise offerings to unlock lag-free experiences across industries. It has also teamed up with Apple and other companies to optimize how their apps work.
In short, L4S is a tech designed to improve video streaming. As T-Mobile‘s president of technology, Ulf Ewaldsson, previously said, this video priority tech will create a better video experience for different apps. He explained that during times of overload, the network will send a message to the app to ask it to adapt to the condition to ensure the video keeps playing smoothly. This will be achieved by lowering video quality, which is better than buffering or freezing.
It’s a video priority technology that creates a better video experience for different applications. [During conditions of network congestion] there is signaling going from the network to the app that tells it to slow down the bit-rates to adapt to the conditions, so you always get optimal rates through for whatever video you’re watching.
—Ulf Ewaldsson, T-Mobile‘s president of technology, October 2024
