A Proposal for a Real-Time Extension of TTCN

In this paper we propose an extension of TTCN (Tree and Tabular Combined Notation) to real-time 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 (EET) and a latest execution time (LET). The informal interpretation of these time values is that a TTCN statement may be executed if it has been continuously enabled for at least EET units and it must be executed if it has been continuously enabled for LETunits. 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 modelled by a timed state sequence which counts for time (progress of time) 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.