User Manual

Table Of Contents

Systemdesign

EachBIUhasacombinedUL/DLporttowardsthebasestationandontheothersidethereareseparateUL/DLports.

TheBIUhasanuplinkamplifierandadownlinkattenuatorthatcanbeset.Thesignalsarethenconnectedtothe

POI’s4couplingfieldstoit’scommonports.The

signalisthensplitonto8portsinthedownlinkandcombinedfrom

8portsintheuplink.FromthePOItherearethenpatchestoeachFOIcardintheframe(8inthisillustrationper

uplinkanddown link)andthe900and1800signalarekeptseparateuntil

theFOI.

Itisnotnecessarytokeepthemseparated;theycouldbecombinedforacommonuplinkanddownlink.However,

doingsomeansthatyouhavefeweroptionsinadjustingthesignallevelswiththegainblockandattenuators,in

eachRFchain.

Multiple operators

ThesamewayasmultiplebandsandservicescanbeconnectedtotheMasterUnititisalsopossibletoconnect

severaloperators.InfactthisisoneofthekeystrengthsofaFiber‐DASsystembecauseitisaccesstechnology

agnostic.Thismeansthatitispossiblewithinthe

samebandtomixdifferentaccesstechnologies–ifcareistakento

avoidproblemswhenmixingGSMandCDMAinthesamesystembecauseoftheveryslowandunsophisticated

powerregulationintheGSMuplink.

Whendesigningsuchasystem,careshouldbetakentoplacetheantennastoavoidanyusersgettingtoocloseand

causingtheRemoteUnittogointolimitmode.

Base station interface

ItisrecommendedthateachoperatoroperatestheirownBIUbecauseotherwisethesettingsoftheBIUmayaffect

morethanonesystemorservice.ThiswaydependingonthesettingsoftheindividualBaseStationtheBIUcanbe

adaptedproperlytogetthemostoutofthesystem.

Remote Unit

Multipleoperatorscanshareoneremoteunit.Doingsomeansthatconsiderationshouldbegiventothenumberof

carriersfromeachoperator,sothattheycanfulfi lltheirrespectivelinkbudgets.Iftheoperatorshavealarge

numberofcarriers,suchasforsomeGSMoperatorswhoeasilyhave6,

8even12carriersitwouldbebettertosplit

themuponseparateamplifiersintheRemoteUnitorevenseparateunitsaltogether.

FOI

TheFOIcanbesharedamongtheoperators.Itisrecommendedtoseetothatthedownlinksignallevelsaresimilar

sothattheysharetheavailablebandwidthofthelaserproperly.Similarlyintheuplink

POI

Whencombiningmultipleoperators itisoftenusefultocombinealltheoperators’uplinksandsplitallthe

downlinksonaper‐bandbasis.ThismeansthatifyouhavemorethanoneFOIinthesystemyoushouldlikelyneed

touseanotheroneplusahybridcombiner/splitter.

Hereisaschematiconhowthiscanbeachieved: