OptiX RTN 600
Product Description
Commercial in Confidence
Page 21 of 44
Note:
When 1+1 FD configuration involves two antennas, the two antennas should have
proper height difference, so that the signals received by the antennas have less space
correlation. This configuration achieves both frequency diversity and space diversity
and is thus called FD+SD.
4.4.3 Switching Principle
I. Transmit Direction
The cross-connect unit transmits two service signals to the active and the standby IF
units. The active ODU transmits an RF signal with a frequency of f1 to the antenna.
The standby ODU transmits an RF signal with a frequency of f2 to the antenna.
Frequencies f1 and f2 have correlation.
II. Receive Direction
The antenna transmits two RF signals at frequencies of f1 and f2 to the active and the
standby ODUs. Both the active and the standby IF units always transmit received
signals to each other. When one unit detects that there are bit errors or faults in its
received signal from the ODU , it selects the better-quality signal transmitted from the
other unit. The cross-connect unit always selects the service signal from the active IF
unit.
Note:
1+1 FD is compatible with HSB. When the active IF unit or the active ODU becomes
faulty, the cross-connect unit selects the service signal from the standby IF unit. This
is called HSB switching. The HSB switching can interrupt services.
4.5 1+1 SD Configuration
1+1 space diversity (SD) is one of the methods used for channel backup. The OptiX
RTN 600, configured with 1+1 SD, uses two antennas that have certain space to
receive the same signal. In this way, the fading in the signal transmission is reduced.
In a 1+1 SD system, choose a proper height difference for the two antennas to reduce
space correlation and thus to avoid simultaneous severe fading occurring to the
receive signals of the two diversities, thus ensuring a better quality of space diversity.
The 1+1 SD switching does not affect services.
