The latest communication technologies invariably consist of modules with dynamic behavior. There exists a number of design tools for communication system design with their foundation in dataflow modeling semantics. These tools must not only support the functional specification of dynamic communication modules and subsystems but also provide accurate estimation of resource requirements for efficient simulation and implementation. We explore this trade-off - between flexible specification of dynamic behavior and accurate estimation of resource requirements - using a representative application employing an adaptive modulation scheme. We propose an approach for precise modeling of such applications based on a recently-introduced form of dynamic dataflow called core functional dataflow. From our proposed modeling approach, we show how parameterized looped schedules can be generated and analyzed to simulate applications with low run-time overhead as well as guaranteed bounded memory execution. We demonstrate our approach using the Advanced Design System from Agilent Technologies, Inc., which is a commercial tool for design and simulation of communication systems.