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to maintain parts of the traffic by switching to a lower modulation, using Hitless
Adaptive Modulation.
The availability for a 56 MHz channel is illustrated in Figure 4.
Received signal
512 QAM
256 QAM
128 QAM
64 QAM
16 QAM
4 QAM Receiver
Threshold
Link throughput
406 Mbps
369 Mbps
326 Mbps
285 Mbps
189 Mbps
94 Mbps
Figure 4
Example of Hitless Adaptive Modulation, 56 MHz
In order to handle channel variations, the channel conditions are continuously
monitored on the Rx side by measurement of Signal to Noise and Interference
Ratio (SNIR). When the receiver, based on this data, detects that channel
conditions imply a change to the next higher or lower modulation, a message
is sent to the transmitter on the other side requesting a higher or lower
modulation. Upon receipt of such request the transmitter starts transmitting
with the new modulation. Each direction is independent. At demodulation the
receiver follows the modulation as a slave.
Hitless Adaptive Modulation can be configured to run in automatic or manual
mode, where automatic mode is default. In manual mode it is possible to
control and set static physical modes and thereby perform advanced fault
tracing or advanced performance tests.
Hitless Adaptive Modulation is compatible with Automatic Transmit Power
Control (ATPC), which is working in a closed loop only in the highest configured
modulation. In lower modulations the output power is set as high as possible.
Note: Hitless Adaptive Modulation requires a license.
1/221 02-CSH 109 172/1-V1 Uen E | 2012-11-07
99.5% Availability
99.9% Availability
99.95% Availability
99.99% Availability
99.995% Availability
99.999% Availability
MINI-LINK PT 2010 Functions – Radio Link
Time
<44 h total down time per year
<9 h total down time per year
<5 h total down time per year
<1 h total down time per year
<0.5h total down time per year
<5 min total down time per year
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