Radio cell

A radio cell is the area in which the signal sent by a transmitter of a mobile radio network can be received and decoded without errors. Each radio cell has a cell ID .

Cell size

The size of a radio cell depends on the meteorological and geographical conditions, settlement structure , vegetation , construction height and type of antennas used , the transmission power and the mobile radio standard used . The cell size is limited by the range of the radio signal. The cell size is only a few meters in diameter for a UMTS - femtocell , 35 km for an ordinary GSM cell and the double for sparsely populated areas (coastal waters). With a cell radius of up to 150 kilometers, the European Aviation Network (EAN) probably has the largest radio cells of all operating cellular networks (as of 2018).

Depending on the mobile radio standard used, the size of the radio cell can change with the load. This effect is called cellular respiration .

With optimal radio conditions, when there is a line of sight between the transmitting and receiving antenna (s) and the first Fresnel zone is free of any obstacles, the maximum range of a radio cell is significantly limited by a certain factor depending on the multiplex method used :

• Timing advance with TDM or a combination of TDM and FDM including OFDM for example: GSM , LTE
• Cell respiration in CDM for example: UMTS

Many mobile radio systems are configured in such a way that mobile telephones that are far away are prevented from using the radio cell. These cell phones are supposed to use nearby radio cells. This prevents handovers triggered by overreach . The detection of distant cell phones takes place via the timing advance . In general, however, the maximum range of a radio cell is limited by the curvature of the earth . The formula for geodetic visibility can be used to calculate the maximum range of a radio cell, which is limited by the curvature of the earth.

Capacity of a radio cell

The possible capacity of a radio cell depends largely on the mobile radio standard used and can range from four simultaneous calls (in a radio cell according to the TETRA standard) to seven simultaneous calls (in a GSM radio cell with a carrier frequency used) and around 98 simultaneous calls (in a UMTS Radio cell with the usual AMR-NB 12.2 kbit / s) up to 860 simultaneous calls (maximum for technical reasons in a GSM radio cell).

Overlapping of the radio cells

Neighboring radio cells, regardless of the standards, usually overlap. There are several reasons for this:

• Terminal devices that do not have an active connection to the network should be given the opportunity to select a new cell if the supply deteriorates. The process of selecting a new radio cell is called cell reselection .
• Terminal devices that have an active connection to the network can be assigned a new cell for further communication by the network without interrupting the communication process. The process of uninterrupted transfer of a communication link from one cell to another is known as handover .
• Mobile networks are of limited availability, if possible redundant realized. If one cellular antenna fails, the neighboring cellular antenna takes over the supply of the failed cell.

See also

• Range (radio technology) , maximum distance between transmitter and receiver with a radio connection
• IMEI serial number for the unique identification of mobile radio devices
• IMSI for the unique identification of network subscribers in GSM and UMTS cellular networks
• IMSI catcher for eavesdropping on cell phone calls
• SIM card to identify the user in the cellular network
• Mobile phone tracking
• Stealth Ping - also Silent SMS or Silent SMS to locate cell phones or to create movement profiles

Web links

• Radio Mobile - program and website for the calculation of radio links and radio cell sizes in the Amateur Radio (English)

Wiktionary: radio cell  - explanations of meanings, word origins, synonyms, translations

supporting documents

1. ↑ http://www.telecomhall.com/parameter-timing-advance-ta.aspx telecomHall - Parameter Timing Advance (TA)
2. ↑ http://4g5gworld.com/blog/timing-advance-ta-lte 4G 5G World - Timing Advance (TA) in LTE
3. ↑ telecomhall.com telecomHall - What is Ec / Io (and Eb / No)?
4. ↑ ETSI EN 300 392-2 (V3.2.1): Terrestrial Trunked Radio (TETRA); Voice plus Data - Part 2: Air Interface , 09/2007, Available here
5. ↑ ^{a b} 3GPP TS 45.001: Physical layer on the radio path; General description; Release 7.8.0 ( English , ZIP / DOC; 805 kB) September 23, 2008. Accessed September 15, 2009.
6. ↑ https://www.umtsworld.com/technology/wcdma.htm UMTSWorld.com - WCDMA (UMTS)
7. ↑ Nortel Networks: Technical Specifications of the GSM Base Transceiver Station (BTS) 18000 ( English ) Archived from the original on November 13, 2006. Information: 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. Retrieved September 15, 2009: "Up to 18 TRX in one single cabinet, Up to 3 radio cabinets"