Klaus vom Hofe


5G tests out of the bus

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Technology is a means, not an end. The most important thing is that it benefits the customers. The new 5G communication standard promises to be more customer-centric than any previous generation. 5G:haus Engineers like Tomáš Kašparec are working hard to make sure this is the case in practice.

Berlin, Winterfeldtstrasse. A warm summer morning. The courtyard is still cast in shadow. Colleagues are arriving at work, cups of coffee in hand. Many are still wearing the headphones they listen to on public transportation. The Deutsche Telekom building is eight stories tall. And up on the roof stands  a transmission mast with the first 5G antennas that were deployed in Europe.

Down below, in the courtyard, stands a white VW bus. Today, like many other days, it serves as the workplace of Tomáš Kašparec and his colleague, Lukáš Kratochvíl. The two engineers are testing 5G New Radio here – the mobile part of the new 5G communication standard. While 5G network deployment is still ongoing across further sites in the Berlin cluster, the trials are happening across 5 sites with 15 already activated antennas. All in all, the preparation and deployment of the sites was the fruits of many months of intense work involving many colleagues from Telekom Deutschland, DT Group teams, as well as the 5G equipment supplier Huawei.

Advanced antennas techniques

They are the first 5G antennas in Europe that are transmitting live: with higher throughput and lower latency. Each transmission mast covers three radio cells with 64 transmitters/receivers. Each one of them carries three smaller antennas – all in all 192. They are integrated in a box on the transmission mast. Advanced antennas techniques are used to form multiple radio beams that automatically direct themselves toward the individual users and vehicles in the cells, rather than "spraying" resources randomly all over the whole cell. The network of the future is flexible and smart and more efficient.

The sliding doors on the bus are open. Tomáš Kašparec and Lukáš Kratochvíl watch the screens and devices in the interior, occasionally flipping switches. The prototype 5G terminal device from Huawei is waiting for its deployment. It is called a "Test CPE", short for "customer premises equipment". It is barrel shaped and still around as large as a big water bottle. It doesn't have any features that customers could use yet, but it transmits in the 5G network. The engineers are setting up a trial. "We're testing the network from the customer perspective. And in a regular environment: through the urban canyons of a major city," says Kašparec.

The preparations take hours

Today they are measuring how a radio cell handles a mass uplink – that is, when many people upload data at the same time. Ultimately, this can create mutual interference. A generator on the VW bus plays a decisive role in the tests: it disrupts the radio cell with this exact interference at the touch of a button. A bit later, Tomáš Kašparec will drive out and measure how this might affect customer speeds. But until they reach that point, the colleagues continue tweaking the parameters in the measurement programs. "The preparations often take hours," he says with a smile, "but the measurements sometimes only take minutes."

As the two engineers configure the devices, they are joined by technicians from network equipment supplier Huawei. It's their hardware on the test bench, along with their measurement program. One of the colleagues offers them a coffee. Czech can be heard, mixed in with Chinese and English. All eyes are focused on the devices.

The excitement is palpable. It has to work. There's no way to compare the measurement results, aside from LTE performance. The data that Tomáš Kašparec and Lukáš Kratochvíl provide from the customer perspective will either verify the differentiation from LTE – or if not, the feedback goes back to Huawei on what needs to be improved to ensure that 5G actually delivers the customer benefits it promises.

Tomáš Kašparec and Lukáš Kratochvíl are conducting these measurement activities for the 5G:haus: Deutsche Telekom’s virtual laboratory to drive 5G technology development and foster innovation, together with leading industry partners. In this case, they are completing a performance assessment of the 5G NR deployment in our live environment from a customer perspective; therefore in terms of coverage, capacity, user experience and mobility. These learning are then shared within the DT technology community, so they don’t need to be replicated by every DT national company. It's an excellent example of the international collaboration within the Group.

Kašparec, now 38 years old, worked for Nokia's network equipment division for nine years after earning his degree in radio technology. He joined Deutsche Telekom in 2015 – and is based in Prague. His experience on the vendor side is now paying off in spades as he works and interacts with experts from these companies on a daily basis.

The time has finally come. The equipment is ready. Kašparec takes his laptop and the CPE to a station wagon that's parked on the street outside. He carefully fastens the test CPE to the back seat and connects it to the computer. Then comes the hard part: finding a parking space in Berlin's Schöneberg borough, in the middle of a 5G radio cell. With that feat accomplished, he gives the order to the VW bus on Winterfeldtstrasse. Kratochvíl starts the interference generator, while Kašparec begins uploading data. Everything works smoothly. The engineer monitors the upload speed on his laptop.

Back in the sunny courtyard on Winterfeldtstrasse, is Tomáš Kašparec visibly satisfied with the test. It is just one of many special moments the team has experienced. He will present the results to the project team soon. What's so special about their jobs? The two engineers don't need long to answer. "We have the chance to shape something completely new here," says Kašparec. "Everything we're doing here is a first. That's a strange feeling sometimes. And we learn new things every day."


What is 5G?

What distinguishes the new global communication standard from the previous mobile generations.