A conventional PtP microwave radio link is
typically designed to operate over long LOS
hops and have a very high availability requirement,
meaning that the outage probability has to
be very low. For example, the availability associated
with a desired data rate can sometimes be as extreme as 99.999 percent, which corresponds
to an average outage time of only 5 min/yr [1].
This is commonly referred to as five nines availability.
Such high availability figures are sometimes
required due to the nature of the traffic
the link carries. For example, an outage in the
traffic to and from a traffic aggregation point is
a very serious event leading to many dropped
connections and poor user experience. To reach
such a high availability figure, the radio link
needs to have a fade margin that is large enough
to compensate for a fading event