Protection Switching - Alcatel-Lucent 9500 MXC User Manual

Chapter 1. Commissioning
Lower Than Expected Fade Margin Situation

Protection Switching

Vol. V-1-6
If the measured fade margin is significantly less than the expected margin,
reasons can include:
• Accuracy of measurement not taken into account. For 9500 MXC, the margin
for error can be up to 3 to 4 dB, given the limitations of software-set power
control, RSL measurement and G.826 error capture. Similarly, the margin for
error for a receive threshold check can also be up to 4 dB given the limitations
of internal RSL and BER alarm measurement. Measurement accuracy can be
improved with the use of an external BER tester.
• Equipment performance outside specification.
• Path loss higher than expected.
• Antenna misalignment.
• Interference from other transmitters.
This topic provides test procedures for 9500 MXC Node Links, Rings, DACs and
NCC/NPC.
Refer to:
• Test Measurement on page 1-7
• Link and Ring Protection Logic on page 1-8
• Confirming Link and Ring Protection on page 1-10
• Hot-standby and Space Diversity on page 1-11
• Frequency Diversity on page 1-13
• Ring Protection on page 1-14
• DAC Protection on page 1-15
• DAC Protection Test Procedure on page 1-16
• NCC/NPC on page 1-17
No protection switch operation is permitted within a one to two minute period from
power-on, which is also the time typically required before CT log-in is permitted.
Alcatel-Lucent