What is CCA (Clear channel assessment)?

Clear channel assessment alludes to the technique of discovering the state of the channel, which is appropriate for the transmission of information. Clear Channel Assessment examines the current state of utilization of a wireless medium. Like function is found in IEEE 802.11 networks and assists in contention avoidance.
The device performs a CCA when transmitting a packet, and examines if the channel is available for transmission. The identified energy on the channel is contrasted with the CA (Clear Channel Assessment) parameter value. If the detected energy surpasses the CA parameter value, the device does not send the packet. The device CCA also inserts a delay before a transmission happens.