A Proposal for a Real-Time Extension of TTCN

In this paper we propose an extension of TTCN (Tree and Tabular Combined Notation) to <i>real-time</i> TTCN. The extension is defined on a syntactical and semantical level. Syntactically, we provide facilities to annotate TTCN statements with two time values, namely an earliest execution time (<i>EET</i>) and a latest execution time (<i>LET</i>). The informal interpretation of these time values is that a TTCN statement may be executed if it has been continuously enabled for at least <i>EET</i> units and it must be executed if it has been continuously enabled for <i>LET</i> units. The operational semantics of real-time TTCN is defined by means of timed transition systems. In timed transition systems an execution of a system is modeled by a timed state sequence which counts for time (time progress) and state (execution of TTCN statements) activities. We define a mapping of real-time TTCN to timed transition systems and give examples in order to show the applicability of our approach.