What are AIS, TDMA and SOTDMA protocols?

AIS (Automatic Identification System) Protocol

The Automatic Identification System (AIS) is a maritime communication system that enables ships to transmit and receive essential information on their position, course, speed and other relevant data. It uses VHF signals to enable ships and coast stations to locate each other and improve maritime safety. The system is particularly useful for collision avoidance, monitoring maritime traffic and collecting data for analysis.

TDMA (Time Division Multiple Access)

TDMA is a multiplexing method that allows several users to share the same communication frequency by assigning them separate time slots. In the context of AIS, this means that several vessels can transmit information on the same frequency without interfering with each other. Each user waits his turn to send his data, enabling efficient management of the radio spectrum.

SOTDMA (Self-Organized Time Division Multiple Access)

SOTDMA is a variant of TDMA specifically designed for AIS. Unlike a traditional TDMA system, where time intervals are predefined, SOTDMA allows ships to autonomously manage their transmission intervals. Vessels monitor channel occupancy and adjust their transmission schedule accordingly. This improves efficiency and reduces the risk of signal collisions, particularly in high-traffic environments.