From now on, passengers throughout the underground network of the Cologne subway will have access to Deutsche Telekom's LTE network. 250 antennas supply platforms and tunnels on all LTE frequencies with up to 300 Mbit/s. What is special about this is that customers of other mobile phone providers can also use parts of the telecommunications infrastructure in the future.
The Stadtbahn, as the mix of tram and subway is called, only runs underground for around 36 of the total of 199 kilometers. So far, passengers on these sections of the route had no or only very poor mobile phone reception. From now on, 250 LTE antennas ensure that fast LTE is also available underground. Around 90 remote units connected via fiber optic supply the 250 antennas installed in the area of the platforms and tunnels, which transmit on the known LTE frequencies of Deutsche Telekom. 800, 900, 1,800, 2,100 and 2,600 MHz are made available underground and deliver up to 300 Mbit/s in the downlink.
mobile phone provider can intrude
The first underground network operator is Deutsche Telekom, but the LTE infrastructure on the antenna side is not only available to Magenta customers. Other wireless service providers such as Vodafone or Telefónica/O2 can intervene and offer their customers high-speed wireless services in the underground. “We share the network with the other network operators and competitors,” said Andre Graf, a Telekom technician and responsible for the expansion of mobile communications in the tunnels and stations of the Cologne subway. As a spokesman for Telekom explained to ComputerBase, the antennas can also cover the frequencies of the other network operators, but these would have to build their own infrastructure apart from the antennas. According to the current status, the LTE network has only been completed for customers of Deutsche Telekom.
Expansion in the small time window at night
Graf also explains the challenges involved in the expansion, because underground work on the cellular network was only allowed when the train was not in use. There were only around two to three hours per night for assembly, because the subway runs until 1:30 a.m. and resumes operation from 4 to 5 a.m. The work was also particularly difficult. “We are not allowed to touch the contact wire that supplies the railway with electricity. And we have a lot of concrete here. As a result, a lot of antennas have to be used so that we can achieve a good coverage with mobile communications. ”
The actual construction time was around six months, but the expansion was a planning phase several years ahead. Many approval procedures with the Kölner Verkehrs-Betriebe (KVB) and the city of Cologne were necessary. The network, which has now been completed, has been set up in such a way that it can be expanded for the future. The topic of 5G does not yet play a role in the current announcement.