  Network-on-chip (NoC) is the most promising design paradigm for the
interconnect architecture of a multiprocessor system-on-chip (MPSoC). On the
downside, a NoC has a significant impact on the overall energy consumption of
the system. NoC simulators are highly relevant for design space exploration
even at an early stage. Since links in NoC consume up to 50% of the energy, a
realistic energy consumption of links in NoC simulators is important. This work
presents a simulation environment which implements a technique to precisely
estimate the data dependent link energy consumption in NoCs with virtual
channels for the first time. Our model works at a high level of abstraction,
making it feasible to estimate the energy requirements at an early design
stage. Additionally, it enables the fast evaluation and early exploration of
low-power coding techniques. The presented model is applicable for 2D and 3D
NoCs. A case study for an image processing application shows that the current
link model leads to an underestimate of the link energy consumption by up to a
factor of four. In contrast, the technique presented in this paper estimates
the energy quantities precisely with an error below 1% compared to results
obtained by precise, but computational extensive, bit-level simulation.
