User's Manual

1
Chapter 1 Introduction
TheBirdfiberdistributedantennasystem(Fiber‐DAS)wasdevelopedfromthestartwithfiber‐opticcableasthe
distributionmedium.Thisallowsforexcellentradioperformanceandbestinclasssystemnoisefigureoflessthan
3dB,fromtheremoteunitantennaporttothebasestationinterfaceport.
TheBir
dFiber‐DASsystemisaflexibleandscalablesolution,meaningthesystemcanbetailoredforalmostany
requirement.Thisflexibilityprovidestheusertheabilitytoadjustmanyofthesystemsparameterstofittheir
specificneeds.
Thisma
nualcontainsdesign,installation,andcommissioningguidelines,aswellassystemmaintenancepractices.It
alsocontainsinformationregardinggeneralpracticeswithinintheindustryaswell.
Fiber-DAS calculator — Inad
ditiontothismanual,theFiber‐DAScalculatorisanindispensabletool,thisExcel
spreadsheetincludesthefollowingfeatures,providinginsighttohowwellthesystemwillperform:
SystemNoiseFigurecalculator
Intermodulationperformancecalculator
Uplink/DownlinkBalance
Dynamicheadroom
RF on fiber
Afiberdistributedantennasystem(Fiber‐DAS)isanefficientmethodoftransmittingradiosignalsoverlarge
distances.OurFiber‐DAScanprovideasmuchas30kmoffiberbetweenthehead‐endandtheremoteunit,
providingthat theradioaccesstechnologyusedintheRadioAccessNetwork(RAN)doe
snotsuffertimingissuesand
thatthefiberlossiswithinthespecification.
TheFib
er‐DASusesaninfra‐redlightsource,modulatedwiththecombinedradiosignalsthatneedtobe
propagated.Thefiberchannelsystemisultrawide‐band,rangingfrom88MHzupto2600MHz,thuscoveringmost
typesofradiocommunicationsystemsincludingasFMbroadcast,VHFcommunicationradios,LT
E,TETRA,GSM,
CDMA,WCDMAandmanyotherradioaccesstechnologies.
Mostlandmo
bileradioandcellularsystemsuseFrequencyDivisionDuplex(FDD)whichmeans:
 Twoseparatefibers,onefortheuplink(signalsfromtheterminaltowardsthebasestation)andoneforthe
downlink(signals fromtheradiobasestationtowardstheterminal)
 Orasinglefiberandthesignalsmustbemultiplexedusingdifferentwavelengths.
Bird’sFib
er‐DASuseswave‐lengthdivisionmultiplexing(WDM)asthestandardconfigurationfeaturingthe
following:.
Sing
lemodefiber
Angledconnectors
Upto15dBopticalloss
Note: SeparateUL/DLfi
berscanbeusedifitisnecessaryordesired.
Thedy
namicofthefiberisgoodenoughtotoleratemulti‐carrier,multi‐bandandmulti‐operatorsolutions,butthey
sharetheavailabledynamicsandifthereisalargenumberofcarriersthefiberattenuationneedstobeconsidered.
Becausethemodula
tionisanalogthesystemrequiresthefiberstobeofsinglemodetype.Allconnectorsusedin
Bird’sFiber‐DASequipmentareSC‐APCtypewitha7°angle.Itisimportantthatallconnectors(i.e.patches)
betweentheMasterUnit(MU)andtheRemoteUnits(RU)beangle
d,otherwisereflectionscouldresultcausing
problemswiththequalityofthesignalsthroughthesystem.