Real-time Communication in Vehicular Ad Hoc Networks (VANETs)

4.3.2 Discrete Event Simulation
According to the particular logical facets that a system intends to represent,
simulation models can artificially be categorized as continuous simulation
models and discrete simulation models [36].
In continuous simulations the state of the system changes continuously with
time elapsing, as illustrated in Figure 4.2. The state change of a continuous
system can be described by some known differential equations.
Figure 4.2 Continuous Simulation Model
On the other hand, the state of a discrete system changes just only at a
discrete set of selected time points (or say moments) in a determined period
[49], as shown in Figure 4.3. For instance, in a traffic modeling scenario,
vehicle arrival at a certain point that occurs at distinct points in a scheduled
period can be considered as an event. A unit in a traffic environment, e.g. a car,
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