Collision avoidance(CA) is a technique used in local area networks and radio networks that avoids simultaneous access to the transmission medium or radio channels by multiple nodes or terminals. This ensures that each node in a network can transmit its signal without colliding with other signals.
The collision avoidance techniques work with carrier detection or reservation techniques. As for carrier detection, these techniques continuouslycheck whether the transmission medium or a radio channel is busy or free. If the transmission medium is used by another station for signal transmission, then all stations that are ready to transmit must wait until the transmitting station finishes its transmission. If radio channels are occupied, the stations ready to transmit look for free radio channels.
In reservation techniques, stations are given a specific time slot or container to transmit data. In radio networks, different radio channels are made available to the individual stations to avoid interference that leads to collisions.
Another collision-free technique is handshaking with mutual acknowledgement.