Mobile communications for industrial applications - CERN

Wireless technologiesFrequency rangesIn contrast to copper or fiber-opticcables, wireless transmission processesuse air as the transmission link.The propagation conditions of electromagneticwaves in air vary considerablydepending on the room properties andthe wavelength of the electromagneticradiation.State-of-the-art modules use techniquessuch as antenna diversity andhigh-performance receivers in order toprevent interruptions in radio traffic.A further aspect is that air is used generallyas the transmission link. This necessitatesthe assignment of various frequencyranges for specific applications,limitation of the maximum permissibletransmission power, and selection ofspecific transmission procedures.A differentiation is made in the frequencyranges of wireless technologiesbetween:· Personal Area Network (PAN) up toapprox. 10 m radius· Local Area Network (LAN) up toapprox. 30 m to 300 m radius and· Wide Area Network (WAN).Current wireless networks such as WirelessLAN according to IEEE 802.11b andBluetooth use frequency ranges in theso-called ISM bands (Industrial, Medical,Scientific Band). Data transfer rates upto 11 Mbit/s can be currently implementedusing the modulation proceduresselected there.TYPEData transferrateAvailableDistanceBluetooth1 Mbit/sYesPCMCIAUp to approx.10 m11 Mbit/sYesPCMCIAFig. 12: Technical specifications of the various radio systemsWireless LAN,IEEE 802.11 bFrom approx.30 m to 300 m9.6kbit/sYesPCMCIAAboveapprox.300 mDepending onenvironmentUp to42 kbit/sYesPCMCIAAboveapprox.300 mUp to42 kbit/sYesPCMCIAAboveapprox.300 mGSM, HSCSD,GPRS, UMTSUp to2 Mbit/sIn thefutureAboveapprox.300 mUp to approx. Above approx. Up to approx.Above 300 mPersonal AreaNetwork (PAN)Local AreaNetwork (LAN)Wide AreaNetwork (WAN)Fig. 13: Wireless networks for different application areas11