Wireless positioning systems have become popular in recent years. Outdoor positioning has been addressed successfully, but location indoors still presents some open issues. One of them is related with the scalability of time-based ranging algorithms. The aim of this study is to develop a simulation framework in order to evaluate the scalability and stability of two time-based ranging positioning algorithms in IEEE 802.11 networks: 2-Way Time of Flight (TOF) and passive TDOA. Details about this simulation model are provided and both algorithms are compared in a proof-of-concept scenario. Results show that Passive TDOA provides a better scalability and more stable measurements than the solutions based on pure 2-Way TOF algorithms.