Radwin 2000 D+ - Page 213

RADWIN2000D+UserManual Release3.6.00 B‐2
SingleAntennasatBothSites ChapterB
maintained.(Forexample,byusingdualpolarizationantennasacrosspolarizationseparation
isattained).
UponselectingAntennaTypeasDual,RADWIN2000D+automaticallyselectsthismodeand
doublestheairrates.
RADWINManagerindicatesacaseofunbalancedRSSbetweenthetwoantennasinthe
centerpanel.
DiversityMode
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eff ective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.
Ante nnadiversityrequiresantennaseparationwhichispossiblebyusingadual‐polarization
antennaorbytwospatiallyseparatedantennas.
UseDiversityinstead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bothsites,theODUsoperatewithasingleradiothatis
connectedtotheANT1connector.Thesecondradioisautomaticallyshutdown.
B.2.3SingleatOneSite,DualAntennasattheOther
InthismodeoneofthesitesusestheODUwithasingleantennawhiletheothersiteusesthe
ODUwithadualantenna.
Theadvantagesinthismodeincomparisontousingasingle antennainbothsitesare
doubledtotalTxPowerandadditionalpolarizationand/orspacediversity(dependingonthe
polarizationofinstalledantennas).
Theairratesused inthismodearesameaswhenusingsingleantennasinbothsites.