Automatic Repeat Request (ARQ) is a communication protocol used in data transmission to ensure reliable delivery of messages. When a sender transmits data, the receiver checks for errors. If an error is detected, the receiver requests the sender to resend the corrupted data. This process helps maintain the integrity of the information being communicated. ARQ is commonly used in various networking technologies, including Wi-Fi and cellular networks. By implementing ARQ, systems can minimize data loss and improve overall communication efficiency. This method is essential for applications where accurate data transfer is critical, such as in file transfers and streaming services.