Baseband processor

A baseband processor is a device in a network [interface controller] that manages all the radio functions ; however, this term is generally not used in reference to Wi-Fi and Bluetooth radios. A baseband processor typically uses its own RAM and firmware. Baseband processors are typically device fabrication|fabricated] using CMOS or RF CMOS technology, and are widely used in radio-frequency and wireless communications.

Overview

Baseband processors typically run a real-time [operating system] as their firmware, such as ENEA's OSE, Nucleus RTOS, ThreadX, and VRTX. There are more than a few significant manufacturers of baseband processors, including Broadcom, Icera, Intel Mobile Communications, MediaTek, Qualcomm, Spreadtrum, and ST-Ericsson.
The rationale of separating the baseband processor from the main processor is threefold:
; Radio performance
; Radio reliability
; Legal

Security concerns

Since the software which runs on baseband processors is usually proprietary, it is impossible to perform an independent code audit. By reverse engineering some of the baseband chips, researchers have found security vulnerabilities that could be used to access and modify data on the phone remotely. In March 2014, makers of the free Android derivative Replicant announced they had found a backdoor in the baseband software of Samsung Galaxy phones that allows remote access to the user data stored on the phone.