There is a 2 way communication channel between each
Radio Node[9] and the Backend System implemented over
the 900 MHz unlicensed ISM band. The RF network is a
mesh type of network, meaning that Radio Nodes that cannot
directly communicate with the Access Node make use of
other available Radio Nodes to relay messages over
dynamically created routes as opposed to using fixed
dedicated repeaters. This eliminates the need for a repeater
infrastructure when deploying the network.
The RF network protocol consists of a mesh network
layer running on top of a Frequency Hopping Spread
Spectrum protocol. Both line powered and battery powered
devices are supported by the network. One Access Node can
control up to 10,000 Radio Nodes Turbines. The general
model of the network is a push model, with the devices
sending data according to predefined schedules downloaded
from the corresponding Access Nodes, which in turn
download the schedules from the Backend System. Alarm
mechanisms are also implemented, with the End Nodes
being capable of generating alarm messages when a
predefined event occurs. The events are like generator
failure, power outages, battery low, cracks detections.