Earth stations in motion (ESIM) communicate, currently, with geostationary-satellite orbit (GSO) systems operating in the fixed-satellite service (FSS) and operate on platforms in motion in the frequency ranges 17.7-20.2 GHz (space-to-Earth) and 27.5-30 GHz (Earth-to-space).
Historically, communication services to mobile platforms were usually provided by satellite systems in the mobile-satellite service (MSS) using relatively low-frequency bands (e.g. the 1.5 GHz, 1.6 GHz, 2.1 GHz, and 2.4 GHz bands). The frequency bandwidths available to individual users in these ranges are relatively low - typically a few kHz to a few hundred kHz. The narrow frequency bandwidths available limit the data rates that can be achieved, which range from a few kbit/s to around 700 kbit/s in a single channel.
The typical data rates currently provided by terminals operating in networks serving ESIMs are around 100 Mbit/s. Data rates may increase to support greater broadband demand or be reduced for applications using smaller earth station antennas while still supporting much higher data rates than are available over existing MSS systems. ITU studies examine how to deliver higher data rates, without impacting other and existing services adversely.
When ships are at sea or aircraft cross the oceans, they are out of reach of terrestrial networks. For such craft on or over vast oceans, an ESIM system can resolve this challenge by providing continuous broadband connectivity for crew and passengers.
ESIMs provide broadband communications on cruise ships, the largest of which can accommodate several thousands of passengers. In addition, ESIM stations can provide broadband communications for managing ship operations, such as for transmission of engine diagnostics, as well as for access to the ship operator's corporate network and for its crew's communications.
In addition, ESIMs meet the broadband connectivity requirements of land vehicles, including trains, coaches, vans, trucks, and motorhomes. Land ESIM can provide connectivity throughout countries and are particularly useful in areas that are not served by terrestrial networks.
ESIM applications also exist for government users and aid organizations that have broadband communication needs for land vehicles, ships, and aircraft. For example, when telecommunications infrastructure is down due to natural disasters, land ESIM can be vital.