Cellular network

from Wikipedia, the free encyclopedia
A transmitter for UMTS and LTE in the Wiesbaden main station of Deutsche Telekom

The term cellular network describes the technical infrastructure on which the transmission of signals for cellular radio takes place. The cellular network essentially comprises the cellular switching network, in which the signals are transmitted and switched between the fixed facilities and platforms of the cellular network, as well as the access network, in which the signals are transmitted between a cellular antenna and the mobile phone (colloquially mobile phone); the access network is also referred to as an air interface .

Distribution of cellular networks

In Germany currently has three mobile networks are operated: According to the network operator to the Federal Network Agency in the first quarter of 2019 the network of Telekom Germany about 44.7 million, the Vodafone about 47.9 million and that of Telefonica Germany about 45.1 million Attendees. In total, there were a little over 137 million mobile phone contracts in Germany.

The oldest networks still in operation are the D-Netz and the E-Netz , which were introduced in Germany in 1991 and 1993 and are based on the GSM standard. At the time, voice transmission was the most common form. In the mid-1990s, however, data transmission gained in importance and required a modernization of GSM . The GPRS standard was developed and introduced for this purpose . The mobile switching network is expanded to include the capability of packet-oriented data transmission , but the radio network is not changed. Finally, the introduction of data-optimized 3G networks aims to increase data transmission rates (see Mobile Internet ) and also eliminates capacity problems in voice transmission. Expanded functionalities, for example in the multimedia area , will follow with the expansion of the 3G networks. The most important 3G standard is the Universal Mobile Telecommunications System (UMTS). With the market launch of “ smartphones ” that increasingly support data applications, the capacity requirements of the networks increased further, which led to the development of the Long-Term-Evolution-Standard (LTE). LTE only uses data transmission and in this respect differs from the older networks that also use circuit switching.

In Switzerland mobile networks operated since 1,993th

→ see main article: History of mobile networks in Switzerland


Cellular antennas on the horse's head

Like the landline network, cellular networks are divided into a core network and several access networks . The function of the core network is to connect the individual access networks, which enable the end users to access the network. The main distinction between cellular and landline networks is the access network, which sets up wireless communication links in cellular networks and thus ensures the mobility of the participants. The access networks are usually radio networks and are often referred to by their English term, Radio Access Network (RAN) . Depending on the standard, there are also other components and subnets that are supposed to guarantee the functionality of the services .

Global System for Mobile Communications (GSM)

→ see main article: Network architecture of GSM

The separation adopted from the fixed network is most pronounced in the GSM system. The base station subsystem (BSS) , which consists of the base stations , provides all functions that are necessary for the connection between the network and mobile subscribers and thus corresponds to the classic access network. The Network Subsystem (NSS) then coordinates the individual BSS. It contains all the components for switching telephone calls and therefore corresponds to the core network. The third component of the architecture is the Intelligent Network Subsystem (IN) , which contains databases that provide additional services. This includes, for example, the administration of prepaid services.

General Packet Radio Service (GPRS)

Basic structure of a cellular network based on the GSM standard

→ see main article: GPRS network architecture

GPRS extends GSM to include the ability to transfer data. Both systems use the same base stations so that no changes have been made to the access network with the exception of a new software version. However, the core network has been expanded to include the ability to set up packet-switching communication links. This enables flexible bandwidths and thus improves the efficiency of the transmission capacity of the channels . For this purpose, the network was given the Packet Control Unit (PCU) to reserve the time slots in the base stations, the Serving GPRS Support Node (SGSN) to route the data packets between the individual radio networks and the Gateway GPRS Support Node (GGSN) to connect the cellular network added to the internet .

Universal Mobile Telecommunications System (UMTS)

→ see main article: UMTS network architecture

UMTS represents the further development of the GSM / GPRS architecture and was also designed for data transmission from the start. At the beginning the core network was hardly changed and only adapted by means of a software update. The structure of the access network is, however, a new development and is called UMTS Terrestrial Radio Access Network (UTRAN).

In contrast to GSM / GPRS, UTRAN does not use a multiplex method for data transmission, but assigns the signals to the participants via individual codes. Later, new architectures such as the Bearer Independent Core Network (BICN) were developed and implemented in the core network , which brought together the previously separate transmission of voice and data connections in a common IP- based transmission method .

Long Term Evolution (LTE)

LTE Evolved Packet System (EPS)
SGW: Serving Gateway
PGW: PDN (Packet Data Network) Gateway
HSS: Home Subscriber Server
ANDSF: Access Network Discovery and Selection Function
ePDG: Evolved Packet Data Gateway
UE: User Equipment
eNodeB: evolved Node B

→ see main article: LTE network architecture

With LTE , the classic methods of signal transmission have been replaced by packet switching and data transmission. A separate voice transmission no longer exists. At the same time, the hierarchical structure has been flattened. Only the actual data traffic is routed through the access and core network, support services such as mobility management or paging are taken over by the Mobility Management Entity , which communicates with both the access network, which is called LTE evolved UTRAN (eUTRAN), and the core network .

Technical processes in cellular networks

Cellular networks are to be assigned to the communication networks and are primarily used to transmit messages . The mobility of the participants makes signal transmission more difficult compared to other networks such as the fixed network. Hence, there are some specific processes that make mobile communication possible. These include transmission over the air interface, mobility management , paging or handover . Depending on the architecture and technology, these functions are provided by other assemblies and are sometimes organized differently ( → see the sections on the architectures above ).


If a network fails, many people are often affected. Some major cell network outages in Germany are listed below:

date operator Problem / number of people affected root cause
October 27, 2000 E-plus 5.7 million customers Error in the signaling software of the switching node
April 27, 2003 T-Mobile several million customers Power failure at the Cologne hub, the failure is noticed too late, the batteries do not last that long
April 20, 2006 O₂ Berliners can no longer call for 6 hours Failure of a digital exchange
April 10, 2008 Vodafone almost 30 million customers in the evening Crash of a computer in the headquarters
May 18, 2008 Vodafone 2 days Internet <-> Mobilnet Hardware failure after maintenance work
April 21, 2009 T-Mobile 3 hours nationwide network failure for 40 million customers Software error in the HLR
September 6, 2012 Telekom Germany Almost all users of the web'n'walk HandyFlat and web'n'walk Handy DayFlat from Telekom Deutschland could not receive or send messages via WhatsApp over the mobile Internet Inadvertently changed parameters due to software update
21st May 2013 Telekom Germany There is a nationwide disruption in the Deutsche Telekom mobile network. Customers do not get a connection to the mobile internet. Problems in data communication
June 11, 2016 Telekom Germany Nationwide customers do not get a connection to the mobile network. Problems in the database; SIM cards cannot be checked for validity
15th May 2018 Telefónica Deutschland Holding Nationwide customers do not get a connection to the mobile network. Software problems at Telefónica
5th November 2018 Telefónica Deutschland Holding Customers in West Germany have no internet connection. Cut fiber optic cable

Plans to shut down cellular communications

The police in Saxony-Anhalt can require any service provider within the meaning of Section 3 No. 6 TKG to prevent communication connections if this is to avert a current danger to the existence or the security of the federal government or a state or to life, limb or Freedom of a person is required.

See also

Web links

Wiktionary: Cellular network  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. Federal Network Agency - mobile radio subscribers. Retrieved July 7, 2019 .
  2. M. Sauter: Basic Course Mobile Communication Systems - UMTS, HSDPA and LTE, GSM, GPRS and Wireless LAN , 4th edition (2011), p. 16, ISBN 978-3-8348-1407-4
  3. M. Sauter: Basic Course Mobile Communication Systems - UMTS, HSDPA and LTE, GSM, GPRS and Wireless LAN , 4th edition (2011), p. 94, ISBN 978-3-8348-1407-4
  4. M. Sauter: Basic Course Mobile Communication Systems - UMTS, HSDPA and LTE, GSM, GPRS and Wireless LAN , 4th edition (2011), pp. 117ff., ISBN 978-3-8348-1407-4
  5. M. Sauter: Basic Course Mobile Communication Systems - UMTS, HSDPA and LTE, GSM, GPRS and Wireless LAN , 4th edition (2011), p. 156ff., ISBN 978-3-8348-1407-4
  6. 3G forum from UMTSlink.at: LTE system architecture - LTE tutorial part 2, accessed: January 18, 2012 ( Memento of the original from January 7, 2012 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.umtslink.at
  7. https://windowsunited.de/telefonica-hat-bundesweit-stoerung-im-mobilfunknetz
  8. https://www.teltarif.de/o2-probleme-nrw/news/74559.html
  9. Interruption and prevention of communication links. Section 33, No. 6, SOG LSA. In: www.landesrecht.sachsen-anhalt.de . juris GmbH, May 20, 2014, accessed on December 9, 2018 : " The police can require any service provider [...] to interrupt or prevent communication connections if this is necessary to avert a current danger . "