The Joint Tactical Radio System (JTRS) with participation from the Wireless Innovation Forum has approved SCA 4.0 as the next generation of the Software Communications Architecture (SCA). The SCA standard was initially released in 1999 and this 'operating system for radios' has enabled several generations of Software Defined Radios during this time.
SCA 4.0 (previously known as SCA Next during its development phase) is a major revision of the standard that can be much better tailored to the specific capabilities of each radio and its mission. Memory and processing power consumption can be reduced significantly. Architectural enhancements also improve security while enabling much faster boot-up times and reconfiguration of the radio.
SCA 4.0 is specifically designed to support the reprogrammability of the radio frequency (RF) and signal processing components of the radio. A radio can be installed in an airplane or vehicle with the knowledge it can be upgraded with a software download. Its open architecture permits a waveform written for one radio to be ported readily to another radio. This capability allows governments and organizations to develop a waveform once, and then reuse the waveform on multiple radios, with the assurance of interoperability with other radios. SCA 4.0 provides an enhanced set of features to support portability and interoperability of waveforms.
SCA 4.0 is more scalable, lightweight, and flexible than SCA 2.2.2. It is compatible with radio sizes ranging from small, single channel radios to prime-power, multi-channel sets. As a technology refresh, it incorporates advances in portability for Digital Signal Processor (DSP) and Field Programmable Gate Array (FPGA) processors and new design patterns for its Application Program Interfaces (APIs).
CORBA (Common Object Request Broker Architecture) is no longer mandated, permitting radio-specific middleware similar to Android’s Remote Procedure Call (RPC) for communication between software components to be used. Registration of components and devices has been redesigned, incorporating a ‘push’ model that substantially reduces communication overhead. This enhancement facilitates dynamic or static configurations and reduces startup times.
A flexible specification for the Application Environment Profile (AEP) defines the minimum operating system features required for a specific radio platform. Units of functionality permit a radio supplier to independently define optional services such as log, event, CORBA, multichannel, etc.
The SCA 4.0 Specification is available for download from the JPEO JTRS Software Communications Architecture (SCA) website.