Licensed Microwave Links vs. Unlicensed Outdoor Wireless Bridges (White Paper)
With unlicensed wireless Ethernet bridge systems it can never be guaranteed that a system will operate interference free and with any predictable reliability. Many manufactured systems can help overcome interference by having a good carrier to interference ratio inherent with the hardware and by proper design and installation.
With licensed microwave links one can have a predictable reliability because of the lack of interference. Many licensed microwave backhaul systems can be design and installed for 99.999% predictable reliability ( meaning the system is predicted to have less than 5 min of outage time a year ) .