W2A-2 Locally Coherent Ultra-Wideband RadioChannel ModelforSensor Networks inIndustrial Environment

We describe anewtransfer function modelfor thestatic ultra-wideband (UWB)radiochannel inindustrial indoor environments forSPIN(Sensor, Positioning, andIden- tification Network) applications. Themodeladdresses prop- agation between oneormoretransmitter andoneormore receiver positions. Itislocally coherent, i.e., itaccounts for smallscaledisplacements oftransmitter andreceiver. Itis a geometry-based stochastic channel modelwhichcombines quasi-deterministic andpurelystochastic components. The environment isrepresented byasetofscatterers whichdescribe theinterior structure ofthebuilding. Modelled quantities are thetransfer functions pertaining totransmission between the transmitter andreceiver positions, thecorresponding setof paths, including directions ofarrival atthereceiver, individual pathgains anddelays. Parameters derived from3-11GHz measurements inanindustry-type hallaregiven. IndexTerms-Ultra-wideband, propagation, industrial radio channel, channel model, sensor networks. I.INTRODUCTION Ultra-wideband (UWB)technology isconsidered attrac- tive, onereason being that itoffers thepotential forawide rangeofsystems that seamlessly combine bothcommunica- tion andlocalization. Oneinstance ofsuchsystems isgiven bysensor networks that besides transmission ofsensor data maybeusedtolocalize theposition ofsensors. Inparticular, theapplication toindustrial environments isinteresting, wherelarge amounts ofsensor andother data areproduced. Within theEC ISTFP6integrated project PULSERS(1) suchsystems havebeeninvestigated. Thispaperreports on achannel modelderived within PULSERStosupport link level simulations foronetypeofmultiple antenna systems (MAS)inindustrial indoor environments forSPIN(Sensor, Positioning, andIdentification Network) applications. Such environments aree.g. infactory halls withseveral machines andmetallic structures positioned throughout thehall. Thesystem inviewinthis paperconsists ofseveral sen- sors, ofwhicheachcommunicates withoneofseveral access points. Dataarerelayed between access points. Sensors are positioned atornearmachines, whileaccesspoints are located sufficiently hightoallowformostly line-of-sight (LOS)conditions forinter access point communication. Fur- thermore, access points areequipped withmultiple antennas that maybeusedtosupport, besides advanced transmission schemes, dataacquisition forlocalization ofsensors. Onlyfewultra-wideband measurements inindustrial en- vironments havebeenreported inliterature sofar(e.g. (2), (3)). Therefore, inthecourse oftheproject weperformed astatic measurement campaign asbasis forthemodelling process covering several scenarios that might beencountered insensor networks. Inthis workwefocus onthetwobasic scenarios required forthegeneric system described above, i.e., transmission between sensors andaccess points, and inter-access point transmission. A majorobjective forthemodelwassimpleness and flexibility. Furthermore, themodelshould begeneric enough tobeapplicable todifferent environments anditshould be suitable forfuture extensions addressing thetime-variance in thechannel. Aswill bedetailed below, wechose ageometry- basedstochastic channel modeltypetoaccommodate these requirements. Thepaperisorganized asfollows. InSection II,ashort summaryofthemeasurements isgiven. Section IIIdescribes themodel; after anoverview ofthemodelling approach in Section III-A, themodelequations andtwosetsofparam- eters derived fromourmeasurements aregiven inSection III-B. Someexample results arepresented inSection IV.