Physical Layer Development Framework for OsmocomBB

Abstract

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 realtime 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.

On the Mapping of Incremental Redundancy into a Physical Layer ASIC

“…Such an architecture is apt for use in previously mentioned applications, such as IoT or M2M communication, where low-power and low-area are indispensable. In order to gain insight into IR mechanisms, an Evolved EDGE capable version of the open source MatPHY GSM framework [10] was equipped with IR functionality. The minimum IR memory size in order to meet the 3GPP throughput requirements is determined based on the receiver performance.…”

“…IR performance simulations have been split into two parts, one that uses parallelization and a sequential one. The former is is done with an extended version of MatPHY, an open source PHY development framework [10]. It outputs BLER p i for i = 0, 1, 2, .…”

“…The latter can be used in an interactive manner to test MatPHY packet switched operations. The original MatPHY presented in [10] has a memory mapped file with a handshake protocol as interface between phydev and higher layers. In order to reuse the same interface in phydev, the minimalistic RLC/MAC software implements the same interface.…”