Forward Error Correction (FEC) is a technique used in data transmission to improve reliability. It allows the sender to add redundant data to the original message, enabling the receiver to detect and correct errors without needing a retransmission. This is particularly useful in environments where resending data is costly or impractical, such as in satellite communications. FEC works by encoding the original data into a larger set of bits. When the data is received, the receiver can use the extra bits to identify and fix any errors that occurred during transmission. This process enhances the overall integrity of the communication system.