LTE: How does it work? What can it do? Where is it available?

LTE (Long Term Evolution) is a mobile communication standard. In the cellular network, mobile data can be transferred over the air in larger amounts and at higher speeds than was possible under earlier wireless communication standards. As the name “Long Term Evolution” implies, this standard will continue to be valid for a long time to come. The launch of 5G will not change this. The LTE network will continue to serve as the foundation upon which the 5G mobile network is built.

What is LTE? 

LTE is also referred to as “4G”, the fourth generation of mobile communication technology. LTE consists of a number of enhancements to the “Universal Mobile Telecommunications System” (UMTS) – the third generation of mobile communications. Accordingly, 5G consists of a series of enhancements to LTE. As such, it is clear that 5G represents the ongoing evolution of cellular technology. 

The standards are defined in the 3rd Generation Partnership Project (3GPP), a worldwide consortium of standards organizations that develop protocols for mobile telecommunications. The work of the 3GPP helps to ensure that mobile communication standards are compatible worldwide. The foundation of the LTE network is an IP network architecture. This is why Deutsche Telekom has also converted its fixed-line network to Internet Protocol (IP).

How long has LTE been around?

The world’s first public LTE network began operation in Stockholm and Oslo on December 14, 2009. The first LTE station in Germany was activated by Deutsche Telekom in Kyritz an der Knatter on August 31, 2020.

How does the LTE network work?

Among other innovations, LTE uses MIMO (multiple input, multiple output) antenna technology. Thanks to its low latency, LTE enables the transmission of voice services (VoLTE: Voice over LTE) and video telephony via Internet Protocol, as well as supporting the use of time-critical applications, such as online games on your smartphone. With its bandwidth of 20 MHz, LTE can achieve speeds of up to 300 Mbit/s downlink and 75 Mbit/s uplink, with a latency of under 20 milliseconds.

GSM and UMTS are the precursors of LTE

Mobile communications broke through to the mass market with the debut of the GSM (Global System for Mobile Communications) standard. Mobile phones became lighter and less expensive. The commercialization of GSM around the world and increasing competition reduced the costs of the system technology and user devices. A major benefit of GSM for users is that even after crossing national borders, they did not need a new SIM card or device. And in addition to voice calls, GSM made it possible to send texts via SMS (Short Message Service). At the peak, users in Germany sent 59 billion short texts per year. With the rise of WhatsApp, Facebook, Instagram, and others, the popularity of SMS has declined sharply. 8.9 million short texts were sent in Germany in 2018.

In addition, GSM standardized the number 112 as the "Worldwide Emergency Telephone Number." Even today, GSM is still the most widely used mobile communication standard, although LTE network coverage has caught up significantly in rural areas in the interim. Overall, 98% of Germany’s population now has LTE coverage in Deutsche Telekom’s mobile network in Germany. 

UMTS is the third generation (3G) mobile communication standard. The UMTS network supported much higher data rates than the GSM network. UMTS enables data transmission speeds of up to 42 Mbit/s. GSM supports a maximum of 220 Kbit/s. A major innovation of the UMTS network was that the higher data rate made it possible to transmit music files. In contrast, LTE achieves speeds of up to 300 Mbit/s in downlink and 75 Mbit/s in uplink. This makes the LTE network much faster, enabling the transmission of video and even streaming.

At the auction of UMTS frequencies in July/August 2000, the Federal Republic of Germany took in 98.8 billion deutschmarks (the equivalent of around 50 billion euros). UMTS was unable to deliver on its lofty promises, however. Its transmission rates could not satisfy customers’ increasing hunger for bandwidth.  Nonetheless, the iPhone heralded the breakthrough of the mobile Internet, even though the first iPhone models didn’t support UMTS. In 2007, Deutsche Telekom launched the iPhone on the German market in an exclusive deal, marking the start of a one-of-a-kind success story. The iPhone 4 was the first model to support UMTS data transmission via HSUPA, with speeds of up to 5.7 Mbit/s.

Another advantage of LTE: when building out the network, the mobile base stations that had already been built for GSM and UMTS could be used – making it unnecessary to establish an entirely new infrastructure for the fourth-generation network.

Who can use LTE?

To use LTE and fast Internet on a mobile device, a user must have an LTE-capable smartphone or tablet, book an LTE rate plan, and be located in an LTE radio cell. That’s no problem today: modern smartphones from Apple, Samsung, Huawei, and many others have native LTE support. Today, inexpensive LTE rate plans for smartphone users aren’t only offered by the network operators, but also by mobile communication discounters. Deutsche Telekom’s LTE network now covers over 98 percent of households in Germany. LTE is available both in cities and rural areas. The buildout of the fourth generation of mobile communication technology will continue in the coming years.

Where is mobile Internet via LTE available?

Network operators have published many maps on the Internet showing their respective LTE coverage. On www.telekom.de/schneller, Deutsche Telekom shows its coverage in its mobile network for LTE, as well as for GSM and 5G. In its broadband atlas, Germany’s BMVI (Federal Ministry of Transport and Digital Infrastructure) shows nationwide network coverage for LTE, along with coverage by the fixed-line network. In addition, Germany’s Federal Network Agency (BNetzA) offers a search function for certain locations with an overview of all available network operators in each location.

Where are the LTE transmission towers located?

Locations on building roofs or existing towers are used for LTE antennas . An antenna on a roof is usually not more than ten meters in height. The height of the towers in Deutsche Telekom’s network is usually 30-40 meters. The supports are usually made of concrete, while steel lattice masts are also used. The antennas are affixed to the antenna masts and are connected to a radio head with an HF cable. The other system technology is installed at the foot of the tower or in an equipment room.

Which frequencies are used for LTE?

Deutsche Telekom currently uses LTE on the following frequencies (key date: June 30, 2020):

• LTE band 3 in the 1.8 GHz range 
  Deutsche Telekom currently uses these frequencies exclusively for LTE.
• LTE band 1 in the 2.1 GHz range
  This frequency band was previously used for 3G/UMTS. As part of its 5G Booster initiative, Deutsche Telekom began using 15 megahertz from this frequency band for Dynamic Spectrum Sharing (DSS), variable for LTE/4G and 5G, in June 2020. 
• LTE band 7 in the 2.6 GHz range
  These frequencies are used primarily in cities, to increase the capacity of the LTE networks. The physical properties of these frequencies do not enable widespread usage due to their limited range.
• LTE band 8 in the 900 MHz range
  Deutsche Telekom uses these frequencies to provide good indoor coverage in cities and wider coverage in rural areas.
• LTE band 20 in the 800 MHz range
  LTE band 20 is essentially the mother of the LTE network. All network operators use these frequencies, especially in rural areas.

Why is LTE also important for 5G? 

Technically, 5G isn’t an independent network, but rather adds new functions and technical features to the existing 4G network. The technical facts (see addendum below) simply rule out considering 4G and 5G in isolation. With the combination of available frequencies, Deutsche Telekom is speeding up the 5G rollout significantly – especially in rural areas. This technology offensive is giving LTE another boost as well, because customers have another frequency band for using LTE and thus more bandwidth. Dynamic Spectrum Sharing (DSS) ensures that this additional spectrum can be used by LTE customers and customers with 5G-enabled devices. DSS and the additional spectrum increase data rates: in rural areas, some speeds have more than doubled. Customers here can surf the Internet at speeds of up to 225 Mbit/s. In urban areas, peak speeds are 600-800 Mbit/s, which means users there also surf even faster than before.  The combination of DSS and the rollout of 5G sites in the 3.6 GHz frequency band makes up the new communication standard. Like LTE, 5G also uses a variety of frequency bands to provide coverage in cities and rural areas.