Carrier Sense TDMA (CSTDMA) is an access method for radio channels used in Automatic Ship and Identification Surveillance System (AIS) Class
B. In the Class B version, the AIS network checks the radio traffic to determine when there is no activity
onthe network. Only when the radio network is completely free of radio traffic can it access a channel and transmit the information
. In Class B, the network must be listened to and used by the base station for reservation. The advantage of CSTDMA operation is that the probability of interference between Class A and Class B is extremely low.