How Does It Work?
So, what makes such advanced connectivity possible on an aircraft zooming across the sky at more than 600 miles per hour and 30,000 feet above the earth? Surprisingly, it’s really not as complicated as you might think.
To bring connectivity services to each passenger, commercial planes need to first establish a connection to an Internet source. This is done using either a satellite or air-to-ground network. Once a connection is made with a given source (satellite or ground-based unit), connectivity can be delivered to passengers via seat back systems, Wi-Fi hotspots and wireless phone signals.
Unlike air-to-ground networks, satellite networks can provide the aircraft with connectivity anywhere around the globe – over land or over water. This makes it possible for passengers to enjoy complete connectivity on all their wireless devices, and even stream live TV during transcontinental and other long-haul flights.
A small satellite antenna located on the top of the plane’s fuselage communicates with a satellite in orbit above the earth. That satellite, which maintains a constant connection with a ground station, acts as a bridge to supply the plane with a live link to the Internet. As the plane moves along its defined route, the nearest satellite in orbit supplies the connection to the plane.
Satellite networks transmit data at different frequency bands, with the amount of available bandwidth increasing along with the frequency. The two common bandwidths used for in-flight connectivity today are L-band and Ku-band. L-band – sometimes referred to as narrowband – operates at a frequency bandwidth between 1-2 GHz, and has only 30 MHz allocated for use. Comparatively, Ku-band networks utilize 500 MHz of frequency bandwidth between 11-14.5 GHz. Another broadband network in development for in-flight connectivity in coming years is Ka-band, with a frequency range of 19-31 GHz and 500 MHz allocated for use. Both narrowband and broadband networks are capable of providing global satellite coverage.
When flying over land, planes can connect directly to ground-based cellular networks, which transform commercial aircraft into flying hotspots that allow passengers to enjoy full connectivity to the web, messaging or email. An antenna located on the bottom of the plane transmits and receives signals to and from towers on the ground (low-power ground transceivers). As the plane moves along its land route, the signal is supplied by the nearest signal source on the ground. When flying over water, however, planes are beyond the reach of these networks.