CSMA-CA

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is a network protocol for carrier transmission. This protocol is used in wireless networks to avoid collisions caused by the simultaneous transmission of data packets. In CSMA/CA, before a device transmits data, it first checks whether the channel is clear. If the channel is busy, the device waits for a random period before checking again. This process is called "carrier sensing". However, due to the hidden node problem, a device might not be able to detect all other devices in the network. To overcome this, CSMA/CA uses an additional technique known as "collision avoidance". In collision avoidance, before sending data, a device sends a short message called a Request to Send (RTS) to the receiving device. The receiving device responds with a Clear to Send (CTS) message. All other devices in the network hear this CTS message and avoid sending data for a certain period, thus preventing collisions. Despite these measures, collisions can still occur. When a collision is detected, the device waits for a random period before attempting to retransmit, further reducing the chance of repeated collisions.