|This article does not cite any references or sources. (November 2012)|
A baseband processor (also known as baseband radio processor, BP, or BBP) is a device (a chip or part of a chip) in a network interface that manages all the radio functions (all functions that require an antenna). This may not include Wi-Fi and/or Bluetooth. A baseband processor typically uses its own RAM and firmware.
Baseband processors typically run a RTOS written in firmware:
The rationale of separating the baseband processor from the main processor (known as the AP or Application Processor) is threefold:
- Radio Performance
- Radio control functions (signal modulation, encoding, radio frequency shifting, etc.) are highly timing dependant, and require a real-time OS.
- Some authorities (e.g. the U.S. Federal Communications Commission (FCC)) require that the entire software stack running on a device which communicates with the cellular network must be certified. Separating the BP into a different component allows reusing them without having to certify the full AP.
- Radio Reliability
- Separating the BP into a different component ensures proper radio operation while allowing application and OS changes.
Significant manufacturers of baseband processors include:
- Intel Mobile Communications- former infineon wireless division
Since the software run on baseband processors is usually proprietary, it is impossible to perform an independent code audit. By reverse engineering baseband chips, researchers have found security vulnerabilities that could be used to access and modify data on the phone remotely. In March 2014, the makers of the free Android derivative Replicant announced that they have found a backdoor in the baseband software of Samsung Galaxy phones that allows remote access to user data on the phone.
- Baseband Processor entry at openezx.org
- Babin, Steve. Developing software for Symbian OS: A beginner's guide to creating Symbian OS v9 smartphone applications in C++. Symbian Press, 2007, p. 80.