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WLAN

Belongs to:
Mobile communications and radio applications
Synonyms:
Access Point, Hotspot, Router, Wi-Fi
Description:

W-LAN is an acronym for "Wireless Local Area Network" and enables a wireless connection among different mobile terminals within a radio network. In general, a standard of the IEEE 802.11 family is employed. Examples of mobile terminals are smartphones, tablets or laptops. Other modern applications are among others radios, E-Readers and bulbs. Present standards, e.g. IEEE 802.11a/h, 802.11b/g oder 802.11n, are situated in the (German) S-band (2 - 4 GHz) at 2,45 GHz oder in the (German) C-band (4 -6 GHz) at 5 GHz. In the course of the year 2015 the standard IEEE 802.11ad is introduced between 57.25 GHz - 65.88 GHz, enabling higher transmission rates in the Gbit range.

Nowadays, WLAN cards are already included in mobile terminals. However, some laptops use PC cards, also known as PCMCIA cards, in order to enable an internet access and provide more memory space. W-LAN base stations are called access points. In order to distinguish between private and public access points, the terms "router" (for private W-LAN) and "hotspot" (for public W-LAN) are used in the following.

Although W-LAN and Wi-Fi are technically not identical, they are often used as synonyms, especially in English-speaking countries.

Frequency ranges:
  • 2.4–2.4835 GHz
  • 5.15–5.35 GHz
  • 5.47–5.725 GHz
Type of field:
electromagnetic

Measurements (acc. to literature)

mobile phone
Measurand Value Feature Remarks
electric field strength 0.06–0.07 V/m (measured) - on an underground platform during peak hours; the same range has been measured while moving on an underground train between two stations; Wifi 2G [1]
Router
Measurand Value Feature Remarks
electric field strength 0.02 V/m (mean, measured) 2.4 GHz averaged over measurements at different locations [2]
electric field strength 0.06 V/m (mean, measured) frequency not specified average value of 18 participants, who were monitored with an RF exposimeter for 24h [3]
electric field strength 0.07–0.6 V/m (calculated) 2.4 GHz value span of 23 measurements with different settings of access point and measuring spectrum analyzer; weighting based on dual time-amplitude computation of the measured WiFi signal [4]
electric field strength 0.1 V/m (maximum, simulated) 5.2 GHz in the head of an adult [5]
electric field strength 0.11 V/m (maximum, measured) 2.4 GHz maximum value out of 41 measuring sights in rural areas [6]
electric field strength 0.12–1.16 V/m (calculated) 2.4 GHz value span of 23 measurements with different settings of access point and measuring spectrum analyzer; weighting considers the duty cycle [4]
electric field strength 0.16 V/m (maximum) 2.4 GHz maximum value out of 50 measuring sights in suburban areas [6]
electric field strength 0.18 V/m (mean, calculated) 2.4 GHz mean value of 23 measurements with different settings of the acces point and the measuring spectrum analyzer; weighting based on dual time-amplitude computation of the measured WiFi signal [4]
electric field strength 0.19–1.47 V/m (measured) 2.4 GHz value span of 23 measurements with different settings of the access point and measuring spectrum analyzer [4]
electric field strength 0.21 V/m (maximum, measured) 2.4 - 2.5 GHz - [7]
electric field strength 0.34–0.47 V/m (mean, measured) 2.4 GHz download: at a distance of 42 cm and a height of 1.15 m [8]
electric field strength 0.36 V/m (mean, calculated) 2.4 GHz mean value of 23 measurements with different setting of the access point and the measuring spectrum analyzer; averaged with considereation of duty cycle [4]
electric field strength 0.5 V/m (measured) 2.4 GHz at a distance of 200 cm [9]
electric field strength 0.51 V/m (mean, measured) 2.4 GHz mean value of 23 measurements with different settings of the access point and measuring spectrum analyzer [4]
electric field strength 0.51 V/m (mean, measured) 2.4 GHz mean value of 23 measurements with different settings of the access point and the measuring spectrum analyzer [4]
electric field strength 0.54 V/m (maximum, measured) 2.4 GHz maximum value out of 77 measuring sights in urban areas [6]
electric field strength 0.68 V/m (maximum, measured) 2.4 GHz maximum value of a 24h measurement in 5 homes in Belgium [10]
electric field strength 0.7 V/m (measured) 2.4 GHz at a distance of 100 cm [9]
electric field strength 0.8 V/m (measured) 2.4 GHz at a distance of 50 cm [9]
electric field strength 0.9 V/m (maximum, measured) 2.4 GHz idle mode: at a distance of 220 cm and a height of 1.25 m [8]
electric field strength 0.97 V/m (measured) 2.4 GHz at a distance of 30 cm [9]
electric field strength 1.05 V/m (maximum, measured) 2.4 GHz download: at a distance of 220 cm and a height of 1.25 m [8]
electric field strength 1.06–1.08 V/m (mean, measured) 2.4 GHz download: at a distance of 40 cm and a height of 0.95 m [8]
electric field strength 1.29 V/m (maximum, measured) 2.4 GHz download: at a distance of 180 cm and a height of 1.25 m [8]
electric field strength 1.6 V/m (maximum, measured) 2.4 GHz download: at a distance of 180 cm and a height of 1.25 m [8]
electric field strength 1.68 V/m (maximum, measured) 2.4 GHz idle mode:at a distance of 180 cm and a height of 1.25 m [8]
electric field strength 1.7 V/m (maximum, measured) 2.4 GHz maximum value of a 24h measurement at 5 schools in Belgium [10]
electric field strength 1.74 V/m (maximum, simulated) 2.4 GHz simulated maximum value in the head of an adult [5]
electric field strength 2 V/m (measured) 2.4 GHz at a distance of 0.5 m [11]
electric field strength 2.47 V/m (maximum, measured) frequency not specified maximum value of 18 participants, who were monitored with an RF exposimeter for 24h [3]
electric field strength 2.79 V/m (maximum, measured) 2.4 GHz idle mode: at a distance of 290 cm and a height of 1.25 m [8]
electric field strength 13.23 V/m (maximum, calculated) 2.4 GHz antenna is positioned at a distance of 20 cm to the modell with a 12 cm thick brick wall separating them; output power of the antenna: 100 mW [12]
electric field strength 11.92 V/m (maximum, calculated) 2.4 GHz antenna is located at a distance of 4 cm to the corner of the room; distance of the model to the antenna: 53 cm; output power of the antenna: 100 mW; thickness of brick wall: 12 cm [12]
electric field strength 21.7 V/m (calculated) 2.4 GHz antenna at a distance of 4 cm to a metal wall; distance of the model to the antenna: 20 cm; output power of the antenna: 100 mW [12]
magnetic flux density 0.041 µT (maximum, calculated) 2.4 GHz antenna is located at a distance of 4 cm to the corner of the room; distance of the model to the antenna: 53 cm; output power of the antenna: 100 mW; thickness of brick wall: 12 cm [12]
magnetic flux density 0.045 µT (maximum, calculated) 2.4 GHz antenna is positioned at a distance of 20 cm to the modell with a 12 cm thick brick wall separating them; output power of the antenna: 100 mW [12]
magnetic flux density 0.072 µT (maximum, calculated) 2.4 GHz antenna at a distance of 4 cm to a metal wall; distance of the model to the antenna: 20 cm; output power of the antenna: 100 mW [12]
magnetic flux density 1.752 mT (maximum, calculated) frequency not specified at the surface of the device at 50 Hz [13]
magnetic field strength 5.64 mA/m (maximum, simulated) 5.2 GHz in the head of an adult [5]
magnetic field strength 25.02 mA/m (maximum, simulated) 2.4 GHz in the head of an adult [5]
power density 0.0097 µW/m² (measured) 2.4 GHz in urban areas of Sweden [14]
power density 0.19 µW/m² (measured) 2.4 GHz in the capital of Sweden (Stockholm) [14]
power density 0.72 µW/m² (measured) 2.4 GHt in urban areas of Sweden [14]
power density 6.63–9.23 µW/m² (mean) 2.4 - 2.5 GHz mean values (depedent on measurement approach) in suburban region [7]
power density 12.6 µW/m² (mean) 2,4 - 2,483 GHz arithmetic mean value out of 130 measuring sights in 2006 [15]
power density 30.29 µW/m² (mean) 2.4 - 2.483 GHz arithmetic mean value out of 130 measuring sights in 2009 [15]
power density 498.34 µW/m² (mean) 2.4 - 2.483 GHz arithmetic mean value of 213 measurement points in 2009 [15]
power density 2–10 mW/m² (measured) 2.4 and 5 GHz at a distance of 1 m [16]
power density 18 mW/m² (simulated) 2.4 GHz at a distance of 1 m inside a school [17]
power density 87 mW/m² (simulated) 2.4 GHz at a distance of 0.5 m inside a school [17]
SAR 0.01 mW/kg (maximum, calculated) 2.4 GHz averaged over the whole body of a 1- to 10-year-old child at a distance of 30 - 100 cm [9]
SAR 12.6 µW/kg (maximum) 5 GHz averaged over the whole body of a 10-year-old child [17]
SAR 19.1 µW/kg (maximum) 2.4 GHz averaged over the whole body of a 10-year-old child [17]
SAR 3.99 mW/kg (simulated) 2.4 GHz in the torso of a 10-year-old child (school environment) [17]
SAR 5.7 mW/kg (simulated) 2.4 GHz in the head of a 10-year-old child (school environment) [17]
SAR 8 mW/kg (maximum, calculated) 2.4 GHz antenna is located at a distance of 4 cm to the corner of the room; distance of the model to the antenna: 53 cm; output power of the antenna: 100 mW; thickness of brick wall: 12 cm [12]
SAR 8 mW/kg (maximum, calculated) 2.4 GHz antenna is positioned at a distance of 20 cm to the modell with a 12 cm thick brick wall separating them; output power of the antenna: 100 mW [12]
SAR 19 mW/kg (maximum, measured) 2.4 GHz antenna at a distance of 4 cm to a metal wall; distance of the model to the antenna: 20 cm; output power of the antenna: 100 mW [12]
SAR 0.1 W/kg (measured) 5 GHz IEEE 802.11a: at a data rate of 7.5 MB/S; averaged over 10 g for an elliptically formed flat phantom filled with liquid [18]
SAR 0.18 W/kg (measured) 5 GHz IEEE 802.11a: at a data rate of 6 MB/s; averaged over 10 g for an elliptically formed flat phantom filled with liquid [18]
SAR 0.25–0.27 W/kg (measured) 2.4 GHz IEEE 802.11g: at a data rate of 26 MB/s; averaged over 10 g for an elliptically formed flat phantom filled with liquid [18]
SAR 0.36 W/kg (measured) 5 GHz IEEE 802.11a: at a data rate of 28 MB/s; averaged over 10 g [18]
SAR 0.44–0.73 W/kg (measured) 2.4 GHz IEEE 802.11b: at a data rate of 6 MB/s; averaged over 10 g for an elliptically formed flat phantom filled with liquid [18]
SAR 0.54 W/kg (measured) 5 GHz IEEE 802.11a: at a data rate of 30 MB/s; averaged over 10 g [18]
power 0.1 W (maximum) 2.4 GHz antenna output power [19]
power 0.2–1 W (maximum) 5 - 6 GHz antenna output power [19]
Hotspot
Measurand Value Feature Remarks
electric field strength 0.7 V/m (mean, measured) frequency not specified out of 100 measuring points in the Netherlands [20]
electric field strength 0.12–3.1 V/m (measured) frequency not specified out of 100 measuring points in the Netherlands [20]
power density 0.1–3 µW/m² (measured) frequency not specified Lindner Hotels & Resorts: at a distance of 5 - 15 m; antenna behind a wallboard at a height of 4; no eye contact [21]
power density 1 µW/m² (measured) frequency not specified GWD Göttingen: at a distance of 50 m; outdoor sector antenna; eye contact [21]
power density 4 µW/m² (measured) frequency not specified Accom (internet operator): at a distance of 40 m; window at a height of 8 m; eye contact [21]
power density 4.3 µW/m² (measured) frequency not specified Accom (internet provider): at a distance of 20 m; window at a height of 8 m; eye contact [21]
power density 4.5 µW/m² (measured) frequency not specified Accom (internet operator): at a sideward distance of 20 m; window at a height of 8 m; eye contact [21]
power density 5 µW/m² (measured) frequency not specified University of Münster: at a distance of 4 m; corridor beneath the room with the omnidirectional antenna, massive ceiling; not eye contact [21]
power density 7 µW/m² (measured) frequency not specified Accom (internet operator): at a distance of 10 m; window at a height of 8 m; eye contact [21]
power density 13 µW/m² (measured) frequency not specified Lindner Hotels & Resorts: at a distance of 7 m; antenna behind a wallboard at a height of 4 m; no eye contact [21]
power density 13 µW/m² (measured) frequency not specified University of Münster: at a distance of 20 m; omnidirectional antenna behind a panel; no eye contact [21]
power density 16 µW/m² (measured) frequency not specified University of Münster: at a distance of 3 m; library above the room with the omnidirectional antenna, massive ceiling; no eye contact [21]
power density 20 µW/m² (measured) frequency not specified Airport München-Erding: at a distance of 50 cm; two sector antennas; eye contact [21]
power density 20 µW/m² (measured) frequency not specified Airport München-Erding: at a distance of 45 m; two sector antennas; no eye contact [21]
power density 20 µW/m² (measured) frequency not specified University of Münster: at a distance of 5 m; omnidirectional antenna at a height of 2 m; eye contact [21]
power density 26 µW/m² (measured) frequency not specified GWD Göttingen: at a distance of 13 m; sum of two antennas behind blinds; no eye contact [21]
power density 29 µW/m² (measured) frequency not specified University of Münster: at a distance of 7 m; omnidirectional antenna behind curtain; no eye contact [21]
power density 51 µW/m² (measured) frequency not specified University of Münster: at a distance of 5 cm; omnidirectional antenna behind a panel; no eye contact [21]
power density 75 µW/m² (measured) frequency not specified Lindner Hotels & Resorts: at a distance of 15 m; antenna behind a cabinet door; no eye contact [21]
power density 80 µW/m² (measured) frequency not specified Airport München-Erding: at a distance of 20 m; sum of two sector antennas; eye contact [21]
power density 95 µW/m² (measured) frequency not specified Lindner Hotels & Resorts: at a distance of 7 m; antenna behind a cabinet door; no eye contact [21]
PC card
Measurand Value Feature Remarks
SAR 1.93 mW/kg (maximum) frequency not specified averaged over the whole body at a transmitted power of 240 mW (situation: laptop is located on the lap) [22]
SAR 8.17 mW/kg–0.18 W/kg (mean, measured) 2.4 GHz averaged over 10 g (head) at an inreasing distance from 3 - 31 cm [17]
SAR 75 mW/kg (maximum) frequency not specified for a laptop, averaged over 10 g of tissues of the upper left thigh at a transmitted power of 240 mW (situation: laptop is located on the lap) [22]
SAR 0.05–0.07 W/kg (min-max value, measured) 5 GHz IEEE 802.11a: for a data rate of 13.3 MB/s; averaged over 10 g [18]
SAR 0.06 W/kg (maximum, measured) 2,4 GHz IEEE 802.11g: for a data rate of 26 MB/s; averaged over 10 g [18]
SAR 0.11 W/kg (maximum, measured) 2.4 GHz IEEE 802.11g: for a data rate of 21.5 MB/s; averaged over 10 g [18]
SAR 0.13 W/kg (maximum, measured) 2.4 GHz IEEE 802.11b: for a data rate of 6 MB/s; averaged over 10 g [18]
SAR 0.43 W/kg (maximum, measured) 2.4 GHz IEEE 802.11b: for a data rate of 6.3 MB/s; averaged over 10 g [18]
SAR 5.22–0.166 W/kg (mean, measured) 5 GHz averaged over 10 g (head) at an inreasing distance from 3 - 31 cm [17]
power density 0.05–2 mW/m² (measured) frequency not specified during data transmission at a distance of 1 m [23]
power density 1 mW/m² (maximum) frequency not specified laptop during file upload/download, measured at a distance of 1 m [24]
power density 3.97 mW/m² (maximum) frequency not specified WLAN pc card in a notebook, measured at a distance of 0.35 m [25]
power density 7 mW/m² (maximum) frequency not specified laptop not communicating with the WLAN [24]
electric field strength 100–150 V/m (maximum, measured) frequency not specified for a laptop [22]
laptop
Measurand Value Feature Remarks
electric field strength 2.89–5.72 V/m (maximum) - at a distance of 0.5 m [26]
power 1–16 mW (maximum) - in the 5 GHz band [26]
power 5–17 mW (maximum) - in the 2.4 GHz band [26]

References

  1. Gryz K et al. (2015): Radiofrequency electromagnetic radiation exposure inside the metro tube infrastructure in Warszawa
  2. Joseph W et al. (2010): Assessment of general public exposure to LTE and RF sources present in an urban environment
  3. Valic B et al. (2015): Typical exposure of children to EMF: exposimetry and dosimetry
  4. Miclaus S et al. (2014): Exposure levels due to WLAN devices in indoor environments corrected by a time-amplitude factor of distribution of the quasi-stochastic signals
  5. Parazzini M et al. (2010): Assessment of the exposure to WLAN frequencies of a head model with a cochlear implant
  6. Joseph W et al. (2012): Assessment of RF exposures from emerging wireless communication technologies in different environments
  7. Breckenkamp J et al. (2012): Residential characteristics and radiofrequency electromagnetic field exposures from bedroom measurements in Germany
  8. Barbiroli M et al. (2011): Assessment of Population and Occupational Exposure to Wi-Fi Systems: Measurements and Simulations
  9. Ibrani M et al. (2014): Assessment of the exposure of children to electromagnetic fields from wireless communication devices in home environments
  10. Verloock L et al. (2014): Temporal 24-hour assessment of radio frequency exposure in schools and homes
  11. Moser M et al. (2006): [Non-ionizing radiation and health protection in Switzerland: basic information]
  12. Martinez-Burdalo M et al. (2009): FDTD assessment of human exposure to electromagnetic fields from WiFi and bluetooth devices in some operating situations
  13. Leitgeb N et al. (2008): Magnetic emission ranking of electrical appliances. A comprehensive market survey
  14. Estenberg J et al. (2014): Extensive frequency selective measurements of radiofrequency fields in outdoor environments performed with a novel mobile monitoring system
  15. Tomitsch J et al. (2012): Trends in residential exposure to electromagnetic fields from 2006 to 2009
  16. Electric Power Engineering Centre (EPECentre) (2012): Health and safety aspects of electricity smart meters. A study into potential health effects of radio frequency emissions from smart meters
  17. Findlay RP et al. (2010): SAR in a child voxel phantom from exposure to wireless computer networks (Wi-Fi)
  18. Bayerischer Industrie- und Handelskammertag BIHK e.V. (BIHK e.V., Deutschland): www.sisby.de - Strahlenbelastung bei Funk-Breitband
  19. Otto M et al. (2007): Electromagnetic fields (EMF): Do they play a role in children's environmental health (CEH)?
  20. Aerts S et al. (2013): Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling
  21. Eddelbüttel D (2002): [Test - WLAN hotspots]
  22. Zhou Y et al. (2008): SAR of Wireless Communication Terminals Operated near the Human Body Using the Example of PCMCIA Data Cards
  23. National Grid (UK): Smart Meters
  24. Foster KR (2007): Radiofrequency exposure from wireless LANs utilizing Wi-Fi technology
  25. Eddelbüttel D (2003): [Unvisible nets - WLAN access points (test)]
  26. Peyman A et al. (2011): Assessment of Exposure To Electromagnetic Fields From Wireless Computer Networks (Wi-Fi) in Schools; Results of Laboratory Measurements