On the design of Modular Software Defined Radio Systems

Software Radio and its enabling technologies have been discussed extensively in the past. The focus of most work is either on a specific hardware part of the transceiver´s signal processing chain, or on algorithm design for the digital baseband. However, a methodology for managing open, Software Defined Radio systems is still in demand. In this paper, the implementation of a software defined physical layer is perceived as a real-time embedded system design problem on multiprocessor hardware, using pieces of software which are unknown a priori. We propose a new way of modeling this design situation. Granularity G is introduced to describe the degree of modularity in software defined communication functions. The speedup s is used to assess the quality of modular implementations. Computer simulations lead us to first observations under the premises of the new model. A mathematical analysis complements these experiments and reveals how to adjust the simulation parameters for interpretable results. The speedup behavior of a simple graph structure is predicted from this analysis. A more complicated structure is then reassessed by means of simulation, finally leading to enhanced guidelines for the design of Modular Software Defined Radio systems.