Cognitive Radio (Maritime VDES)

Cognitive radio in the maritime VDES context is adaptive spectrum use where the VHF Data Exchange System senses channel occupancy and assigns the application-specific message (ASM) and VDE channels dynamically to avoid interference with AIS. VDES, standardized in ITU-R M.2092, layers ASM and a higher-rate VHF data exchange on top of legacy AIS while protecting the AIS reporting channels. Cognitive techniques manage the shared, congested VHF maritime band so terrestrial and satellite VDES links coexist with AIS Channels 87B and 88B without degrading collision-avoidance reporting.