Using PRISM model checker as a validation tool for an analytical model of IEEE 802.15.4 networks

Commonly, simulation by using an existing network simulation tool or a simulator developed from scratch is employed for validation of analytical network performance models. An analytical model of star-shaped wireless sensor networks has been proposed in the literature in which, upon receiving a query from the coordinator, each sensor node sends one data frame to it by executing the IEEE 802.15.4 unslotted carrier-sense multiple access with collision avoidance algorithm. The model consists of expressions for calculation of the probability of successful receipt of the data at a certain time and the like. The authors of the model have written a special simulation program in order to validate the expressions. Our aim was to employ probabilistic model checker PRISM instead. PRISM only requires the user to formally specify the network as a kind of state machine and the queries about the probabilities sought in the form of logical formulas. It finds the probabilities automatically and can present them on graphs. We show how to specify the networks formally in such a way that all the expressions from the analytical model can be validated with PRISM. For those networks containing a few nodes, the validation can be carried out by normal model checking, which, in contrast to the simulation, always checks all the possible network behaviors, whereas statistical model checking can be used for the larger networks.