The Waveform Description Language (WDL) supports specification of reactive systems: systems that react to external events. The language combines familiar block diagram and state machine concepts. Whereas some traditional tools and languages provide ill-defined semantics and a behaviour optimised for a particular implementation domain, WDL has the well defined semantics necessary to provide an unambiguous specification. WDL supports refinement to add or revise detail, and so with a modest amount of refinement, the specification can be simulated to demonstrate completeness. After more substantial refinement the specification may be adapted to suit a particular implementation strategy.
The specification language is primarily graphical: blending hierarchical message flow concepts from block diagram tools such as Ptolemy, and hierarchical state machines from Argos, SDL or UML. The underlying language has interchangeable XML and textual dialects to support persistent representation of the graphics, specification of non-graphical entities, and the non-graphical aspects of graphical entities. The language semantics combines the synchronous reactive principles of languages such as Esterel and the dataflow capabilities of Ptolemy so that the sporadic event driven requirements of high level specifications, and the predictable intensive computation patterns of low level specifications can be represented consistently.
The specification can be partitioned and refined to suit simulation or execution in a variety of contexts and languages.
The aim of WDL is to bring together the good characeristics of many niche languages to create an industry standard specification language.
Once WDL is used to replace existing informal textual specifications, specifications will improve through
Once tool sets are available to handle the extra stages of compilation needed to convert a specification into an implementation, products will benefit from
Once tool sets are available with standard interfaces, the quality of tools may begin to improve rapidly, and libraries of reusable entities may be effectively exploited.
All of which provides the requisite flexibility to handle future requirements that involve supporting ever increasing numbers of modes of operation on both general and special purpose hardware platforms. These motives are particularly strong in the radio field, which is why much of the initial consideration has been concerned with Programmable Digital Radios or Software Definable Radios. There is however nothing uniquely special that is not applicable to another domain that involves continuous operation reacting to external stimuli.
A brief overview of the use of WDL was extracted from the Phase 1 final report. A better oveview is now provided by the Milcom'2001 paper. A more substantial description is provided by the book chapter. More detailed but very preliminary information may be found in the project document:s describing the language and library.
An extensive example of the use of WDL is provided by the example parameterisation of the FM3TR waveform. A brief summary of the full FM3TR Decomposition is available. Some indications of how a specification could be transformed for use on a JTRS radio platform is given here.
These pages describe ongoing work, some of which is publicly funded. More details are available, however not all documents have yet been publicly released, and so some links may refer to non-existent pages or documents.
C.Waugh, UK PDR Phase 1 Final Report, P6957-11-001 Issue 1, Racal Research Limited © DERA, 11 April 2000. pdf
E.D.Willink, PDR Library Primitives, P6957-11-004 Issue 1, Racal Research Limited © DERA, 13 April 2000. pdf
E.D.Willink, FM3TR Decomposition, P6957-11-005 Issue 1, Racal Research Limited © DERA, 13 April 2000. pdf
T.J.Gregory, M.A.Stern, E.D.Willink, WDL & JTRS, P6957-11-013 Issue 1, Racal Research Limited © DERA, 13 April 2000. pdf
E.D.Willink, Waveform Description Language, P6957-11-014 Issue 1, Racal Research Limited © DERA, 13 April 2000. pdf
E.D.Willink, Waveform Description Language : Moving from Implementation to Specification, Milcom'2001, 28-31 October 2001, abstract, pdf, ps
E.D.Willink, The Waveform Description Language, in Walter Tuttlebee (ed), Software Defined Radio: Enabling Technologies, John Wiley, 2002 pdf
E.D.Willink, Definition of Embedded Software using the Waveform Description Language, Software Defined Radio Forum, 12th September 2000, ppt
E.D.Willink, Definition of Reactive Systems using the Waveform Description Language, FM3TR Working Group, 24th October 2000, ppt
E.D.Willink, Definition of Reactive Systems using the Waveform Description Language, Software Defined Radio Forum Waveform Development Environment Workshop, 1st November 2000, ppt
E.D.Willink, Waveform Description Language : Technical Overview, MIT Laboratory for Computer Science, Software Design Group, 20 March 2001, ppt
E.D.Willink, Waveform Description Language : Moving from Implementation to Specification in Ptolemy II, Ptolemy Mini-conference, 22-23 March 2001, ppt
E.D.Willink, Waveform Description Language, and its application to reactive systems, SMi Software Radio Conference, 4-5 April 2001, ppt
Last updated 01 Febuary 2007