The work describes a specific approach to modeling and simulating Wireless Sensor Networks (WSN), using nested Petri Nets formalism. The tool for modeling/simulating WSN must take into consideration resources, time and sensors cost. Even though Petri Nets are good for modeling dynamic systems, they do not have enough means to express these aspects. Hence some extension were introduced to handle them.

Time Petri nets are an extension of Petri nets formalism with time specifications on transitions. The formalism is convenient for model distributed systems and enables capturing the time characteristics of distributed system activities. The primary tool for models behaviour understanding is reachability graph. In [10] the algorithm for constructing Time Petri net reachability graph was suggested. It is based on essential states, but the number of states in the resultant net reachability graph increases when time specification are scaled up, while the behaviour of the net is invariant under time specification scaling. We study the modification of this algorithm that allows to build Time Petri nets reachability graphs more efficiently using common divisors of the time specification in the components of a Time Petri net.