Time-Slotted Channel Hopping has become a main medium access mechanism for low-power industrial wireless networks. It combines time synchronization with scheduled transmissions and channel hopping to support reliable and predictable communication. Although TSCH could improve robustness, its performance is still influenced by frequency-dependent and time-varying wireless conditions in practice. To understand these effects, it is necessary to design evaluation tools that can capture channel behavior without relying on complex physical-layer models. This thesis presents a discrete-event simulation framework for TSCH networks which integrates probabilistic channel modeling at the system level. The framework represents packet delivery outcomes using configurable probabilities. It supports static reliability models as well as frequency-dependent and time-varying channel conditions.