Uplink record with 5G-advanced modem: 550 Mbit/s in the network of T-Mobile USA

The US network operator T-Mobile is the first in the world to reach an uplink speed of 550 Mbit/s with a frequency spectrum below 6 GHz. This is reported by the US subsidiary of Deutsche Telekom. For the live demo at a public 5G base station in Seattle, T-Mobile, the network supplier Nokia and the fashion supplier Mediatek have worked together. Mediatek has harvested some attention with his 5G modem at the beginning of the year together with Ericsson and Telstra For the first time, 10 Gbit/s in reception mode delivered.

The record stands out because many network operators traditionally put the reception speed of mobile phone technology in the foreground, although the broadcasting is gradually becoming more important and puts applications such as cloud synchronization or sending high-resolution videos.

The next big thing

Ulf Ewaldsson, President of Technology at T-Mobile, even believes “Uplink will be the next big thing”. The company wants to prepare the ground for games in fast-echo time and professional applications such as remote maintenance with AR and VR headsets.

For the live demo, the three partners have used a base station and an unspecified smartphone prototype according to the 3GPP-standard release 17 with uplink switching tx switching. In the smartphone, this was on the occasion of the Mobile World Congress 2025 presented M90 modem from Mediatek. Nokia steered Airscale radio and system modules as well as software functions according to 5G-advanced, a spokesman said when asked. The partners did not comment on the distance or the exact radio conditions.

TX switching is a comparatively new technique that presents smartphones in particular with challenges. At best, you can use two antennas for the transmission direction and need modern techniques such as the Uplink-Carrier aggregation (UL-CA) and Uplink-Mimo (UL-MIMO) to bundle several radio tapes efficiently. T-Mobile configured a total of 135 MHz in the radio spectrum in the Nokia base station. Of this, 35 MHz accounted for the tape N25 and 100 MHz to N41.

Looking closer, it is an almost typical TX switching configuration: two radio bands are bundled in two operating modes, an FDD and a TDD band. Vodafone also has this concept In January 2024 implemented at his UL-TX switching record of 273 Mbit/s.

But if network operators are not exactly chasing a record, they supply customers alone with FDD ligaments. The transmission and reception direction are divided into different spectrum parts, which are equally wide, for example 5, 10 MHz or 20 MHz per direction (frequency division duplex). As soon as a mobile phone device has snapped into a first FDD band, it can both send and receive data. Because the direction of reception dominates most users, part of the broadcast spectrum is normally broke in the FDD operating mode.

More demand for more upload speed

In TDD mode (Time Division Duplex), both transportation runs in a radio band, but in different time slots. Because network operators can assign the time slots as required, the TDD mode is considered an accelerator of the main direction: If you expect customers to mainly download, in addition to one or more FDD ribbons, they receive at least one TDD band that reserves the majority of the slots for the downlink and thus drastically accelerates downloads. For the uplink record, the slot layout is turned over and the transmission direction has a disproportionate number of time slits.

Overall, the progress appears welcome, although few users still rely on real-time gaming and VR headsets in interaction with mobile phone networks. In a future everyday life, stationary 5G routers with Uplink TX switching are also desirable, simply because you can pull the electricity required for the additional power out of the socket. The uplink turbo is likely to use the manageable energy supply of smartphones far too quickly. Inpatient routers also seem to be interesting because they offer enough space for four broadcasting units and thus for even higher transmission speeds.