Understanding the software communications architecture

The Software Communications Architecture is an open architecture developed by the U.S. Department of Defense to standardize the development of software-defined radio, improve communication systems interoperability, and reduce development and deployment costs. The SCA facilitates software reuse and technology insertion by abstracting radio applications from the supporting platform and defining a common operational environment across platforms. The SCA relies on commercial standards, classic software engineering principles, and software design patterns. While some SCA design choices are controversial and tightly tied to the specific needs for which it was developed, the basic design principles of software reuse and abstraction are sound and necessary if SDR is to achieve its full potential. Some of the techniques and concepts used in the SCA may be foreign to a communications engineer, and can result in confusion and long learning curves. The understanding of these concepts is of great relevance for communications engineers independent of any opinion about the SCA itself. This tutorial is aimed at educating communication engineers on these software engineering principles and describing how the SCA applies them to achieve its goals. We describe the different interfaces of the SCA that provide a framework for the implementation of SDR. The tutorial provides introductory material to understand the basic operation of the SCA as implemented in the Open-Source SCA Implementation::Embedded developed by Wireless @ Virginia Tech.