User's Manual Part 1

Designing a Fusion Wideband Solution
Page 62 InterReach Fusion Wideband Installation, Operation, and Reference Manual
© 2013 TE Connectivity Ltd D-620616-0-20 Rev H • TECP-77-044 Issue 7 • May 2013
OVERVIEW
DesigningaFusionWidebandsolutionisamatterofdeterminingcoverageandcapacityneeds.
Thisrequiresthefollowingsteps:
1 Determinethewirelessservice provider’sre
quirements;referto“DownlinkRSSI
DesignGoal
”onpage64.
Thefollowinginformationistypic
allyprovidedbytheserviceprovider:
• Frequ
ency(forexample,1900MHz)
• Band(forexample,“A‐F”ban
dinthePCSspectrum)
• Protocol(fo
rexample,CDMA,GSM,1xRTT,GPRS,andsoon)
• Number
ofsectorsandpeakcapacitypersector(translatestothenumberofRFcarriers
thatthesystemwillhavetotransmit)
• DownlinkRSS
Idesigngoal(RSSI,receivedsignalstrengthatthewirelesshandset,for
example,–85dBm)
Thedesigngoalisalwaysastrongersign
althanthemobilephoneneeds.Itincludes
inherentfactorswhichaffectperformance.
• RFsource(b
asestationorbidirectionalamplifierorrepeater),typeofequipmentif
possible.
2 Determineth
edownlinkpowerpercarrierfromtheRFsourcethroughtheDAS;refer
to“MaximumOu
tputPowerperCarrier”onpage65.
Themaximumpowerpercarrierisa
functionofmodulationtype,thenumberofRFcarriers,
signalqualityissues,regulatoryemissionsrequirements,andFusionWideband’sRF
performance.Powerpercarrierdecreasesasthenumberofcarriersincreases.
3 Deve
lopanRFlinkbudget;referto“EstimatingRFCoverage”onpage82.
KnowingboththepowerpercarrierandRSSIdesigngoal,youcandevelopanRFdownlink
link
budgetwhichestimatestheallowablepathlossfromanRAU’santennatothewireless
handset.
allowablepat
hloss=powerpercarrier+antennagain–designgoal
Satisfactoryperformancecanbeexpectedaslongaspathlossisbelowthislevel.