Current embedded applications are migrating from single processor-based systems to intensive data communication requiring multiprocessing. The performance demanded by these applications requires the use of heterogeneous multiprocessing architectures in a single chip (MPSoCs) endowed with complex communication infrastructures, such as Networks on Chip or NoCs. NoC parameter choices, such as network dimensioning, topology, routing algorithm, and buffer sizing then become essential aspects for optimizing the implementation of such complex systems. This paper presents NoC models that allow evaluating communication architectures through the variation of parameters during MPSoC design. Applicability of the concepts is demonstrated through two heterogeneous MPSoC case studies: an MJPEG decoder and an H.264 encoder.