In this method, a station that wants to transmit data continuously senses the channel to check whether the channel is idle or busy.
If the channel is busy, the station waits until it becomes idle.
When the station detects an idle-channel, it immediately transmits the frame with probability 1. Hence it is called I-persistent CSMA.
This method has the highest chance of collision because two or more stations may find the channel to be idle at the same time and transmit their frames.
When the collision occurs, the stations wait a random amount of time and start all over again.