Date Added: Sep 2011
The authors propose a timed broadcasting process calculus for wireless systems where time-consuming communications are exposed to collisions. The operational semantics of their calculus is given in terms of a labeled transition system. The calculus enjoys a number of desirable time properties such as time determinism: the passage of time is deterministic; patience: devices will wait indefinitely until they can communicate; maximal progress: data transmissions cannot be delayed, they must occur as soon as a possibility for communication arises. They use their calculus to model and study MAC-layer protocols with a special emphasis on collisions and security. The main behavioural equality of their calculus is a timed variant of barbed congruence, a standard branching-time and contextually-defined program equivalence.