Installation Guide

TVWhiteSpaceInstallationGuide Release1.0 B‐2
ScopeofthisAppendix
ForexamplewithadualantennaRADWINTVWhiteSpacecantransmitatmodulationof
64QAMandFECof5/6 andgetanairrateof130Mbps,comparedto65Mbpswithsingle
antenna.
Toworkinthismode,eachantennaportmustbeconnectedtoanantenna,theRSSlevelin
bothreceiversshouldbebalancedandaminimalseparationbetweentheantennasmustbe
maintained.(Forex ample,byusingdualpolarizationantennasacrosspolarizationseparation
isattained).
UponselectingAntennaTypeasDual,RADWINTVWhiteSpaceautomaticallyselectsthis
modeanddoublestheairrates.
TheRADWINManagerindicatesacaseofunbalancedRSSbetweenthetwoantennasinthe
HBSpanels.
DiversityMode
(notapplicableforFCCproducts)
DiversityModeusestwoantennastoimprovethequalityandreliabilityofthelink.Often,
thereisnotaclearline‐of‐sight(LOS)betweentransmitterandreceiver.Insteadthesignalis
reflectedalongmultiplepathsbeforefinallybeingreceived.
Eachsuch“bounce”canintroducephaseshifts,timedelays,attenuations,andeven
distortionsthatcandestructivelyinterferewithoneanotherattheapertureofthereceiving
antenna.Antennadiversityisespeciallyeffectiveatmitigatingthesemulti‐pathsituations.
Thisisbecausemultipleantennasaffordareceiverseveralrecordingsofthesamesignal.Each
antennawillbeexposedtoadifferentinterferenceenvironment.Thus,ifoneantennais
undergoingadeepfade,itislikelythatanotherhasasufficientsignal.Collectivelysucha
systemcanprovidearobustlink.
Antennadiversityrequiresantennaseparationwhichispossiblebyusingadual‐polarization
antennaorbytwospatiallyseparatedantenna s.
UseDiversityinst
eadofSpatialMultiplexinginthefollowingsituations:
• WhenthesystemcannotoperateinSpatialMultiplexingMode
• Whenoneofthereceivershashighinterferencecomparedtothesecondreceiver(i.e.
thesystemis“unbalanced”)
• WhenyouachievehighercapacityinDiversityModethaninSpatialMultiplexingMode
• Whenhighrobustnessisofimportanceand
thecapacityofDiversityModeissufficient
(upto25Mbpsfullduplex)
B.2.2SingleAntennasatBothSites
ByselectingasingleantennaattheHBSandSU,theODUsoperatewithasingleradiothatis
connectedtotheANT1connector.Thesecondradioisautomaticallyshutdown.
FOR REGULATORY USES ONLY