Analiza technologii beamforming (wieloantenowych systemów WiFi) we współczesnych systemach dostępu bezprzewodowego.pdf

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Marketing v.
Reality in Multi-
Antenna Wi-Fi
Guide to Beamforming
March 2011
Scott Reeves
Technical Director
EMEA
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Summary
Wi-Fi vendors are marketing chip-based beamforming more heavily
They gloss over limitations, naturally
Mutually-exclusive chip-based beamforming and spatial multiplexing
Zero gain from implicit beamforming, minimal (2 dB) from explicit
Zero client support today for explicit
Customers are easily confused, since all beamforming sounds the
same to any non-specialist
A back-to-the-basics view (focusing on simple but technically
accurate descriptions how multi-antenna techniques really work)
can cut through the confusion
...and illustrate why Ruckus BeamFlex remains the superior
approach
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Conventional Wi-Fi: omni Tx pattern
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BeamFlex Smart Antennas
Vertically -polarized
antenna
elements
Auto
RF signal
optimizer
(Optimises RF coverage based on device
orientation)
Horizontally-
polarized
antenna
elements
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Automatic Interference Mitigation (AIM)
Interference Rejection is Essential
7 dBi signal gain
Chip-based beamforming has no
mechanism to reject interference
Omni-directional antennas can’t
ignore interference
BeamFlex mitigates interference
by positioning antenna nulls in
specific directions
Negating interference can be
more beneficial than signal gain
-10db
interference
rejection
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