Physical Layer Development Framework for OsmocomBB
The open source GSM protocol stack of the OsmocomBB project offers a versatile development environment regarding the data link and network layer. There is no solution available for developing physical layer baseband algorithms in combination with the data link and network layer. In this paper, a baseband development framework architecture with a suitable interface to the protocol stack of OsmocomBB is presented. With the proposed framework, a complete GSM protocol stack can be run and baseband algorithms can be evaluated in a closed system. It closes the gap between physical layer signal processing implementations in Matlab and the upper layers of the OsmocomBB GSM protocol stack. An embedded version of the system has been realized with FPGA and PowerPC to enable real-time operation. The functionality of the system has been verified with a testbed comprising an OpenBTS base-station emulator, a receiver board with RF transceiver and our developed physical layer signal processing system.
KeywordsBaseband signal processing Physical layer hardware architectures OsmocomBB GSM protocol stack L1CTL messages
We would like to thank Dominic Just and Pirmin Vogel for their valuable work during their student projects and Raphael Rolny for this consultation regarding user cooperation. We thank ACP AG for providing us the IRIS305 single-chip RF transceiver for our testbed setup. In addition, we want to thank David Tschopp and Dominik Riha for their support on the receiver board. This work was funded by CTI, Switzerland, in collaboration with ACP AG.
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