AP: Application Processor, i.e., an application chipset
BP: Baseband Processor, i.e., the baseband chip
FCC (Federal Communications Commission) requires separate authentication on BP and AP, because the associated function (signal modulation, coding, radio frequency and displacement) are highly time-dependent RF control, which preferably can function in a CPU core run, and a real-time operating system running on the CPU core, the core operating system and the AP so that the drive will not cause the device to bug the data transmitted to the mobile network catastrophic; and once the BP is good design and certification, No matter how you change the use of the operating system and application software, it can perform proper communication functions, mobile phone designers can more freely design the user interface and application software.
BP primary role is to send and receive various kinds of data, i.e. communication and closely related, BP algorithm in the DSP implementation of the protocol, the data encoding and decoding, the CPU BP is responsible for coordinating and controlling the communication with the base station AP. BP power management module have a great impact on the standby time of it, because most of the time the cpu BP should be in idle state, open only from time to time to see if there is a call into the paging channel. In addition, BP and SIM modules are directly connected, the operation of the SIM card is performed by BP.
