MINI-LINKEandEMicro
8.1.3 1+1 Protection Switching
8.1.3.1 Switching due to Hardware Failure
Transmitter Switching
Maximum interrupt time on any traffic at hot standby switching, that is the
time from detected failure in redundant equipment until regained frame
synchronization in final demultiplexer on the receiving side, is 200 ms.
Receiver Switching
Maximum interrupt time for hardware switching is 40 ms.
8.1.3.2 Switching due to Fading
Receiver Hitless S witching
With standby channel working at –60 dBm RF input level and operating channel
RF input moving from –60 dBm down to –90 dBm at a velocity of <20 dB/s, the
receiver switching is hitless.
Note: Manual switching controls both the RMX Switch and Hardware Switch,
see also Section 3.9.2.6 on page 58.
8.1.4 Power Splitter Attenuation for 1+1 Systems
The power splitter is used when two radio units are connected to one antenna.
The power splitter comes in two versions:
• Symmetrical, with equal attenuation in both channels
• Asymmetrical, with one main channel and one standby channel
The symmetrical version is mainly used in 1+1 working standby systems where
both radios are transmitting (Working standby provides not only hardware
protection but also frequency diversity). The asymmetrical version is mainly
used in 1+1 hot standby systems where only one radio is t ransmitting.
If the fade margin is low in a 1+1 hot standby system, the symmetrical power
splitter is recommended. This is due to the fact that the fade margin will be
reduced by almost 11dB in worst case.
133
AE/LZT 110 2012 R8C 2002- 03-04
To Next Page
Loading...