Radwin RW 2000 Series, Руководство по установке, Страница: 104 / 127

Page 104 June 2023
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Dual Antennas at the RT‐A(HBS) and RT‐B(HSU)
When using dual antennas at both sites (single bipolar antenna or two unipolar antennas)
you can choose between Spatial Multiplexing Mode and Diversity Mode.
Spatial Multiplexing Mode
Under this mode, the system doubles the link capacity. At the same time, it keeps the same
rate and modulation per radio as was used with a single antenna, thus increasing capacity,
range, and availability.
For example, at 80MHz CBW, using a dual antenna, a RADWIN 2000 D
‐
Plus ODU can
transmit at modulation of 256QAM and FEC of 5/6 and can get an air rate of 866.7 Mbps,
compared to 433.3 Mbps with a 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 minimum separation between the antennas must
be maintained (for example, by using dual polarization antennas a cross-polarization
separation is attained).
Upon selecting the Antenna Type as Dual, a RADWIN 2000
‐
Plus Family ODU automatically
selects this mode and doubles the air rates.
The RADWIN Manager indicates a case of unbalanced RSSs 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 no clear line
‐
of
‐
sight (LOS) between the transmitter and the 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 a separation between the antennas; this is done 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)
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 ODU is automatically shut down.