The main function of the baseband processor in mobile phones is to manage communication tasks. It handles all radio functions, including voice calls, SMS, and data transmission, ensuring seamless connectivity across various networks, like GSM or CDMA. This specialized processor works alongside the application processor to execute its tasks while minimizing power consumption. It is integral for maintaining call quality and network stability, and it supports features like 4G LTE and dual-SIM operation. Overall, the baseband processor is crucial for the mobile device's communication capabilities.