Localization of Things (LoT) is a promising solution for smart warehouses, where several robots work autonomously in logistics processes. In this work, we consider the use cases of indoor localization systems based on Ultra Wide Band (UWB). In our system model several agents, divided into tags and anchors, are considered. They are mobile and operate in the same warehouse, so their numbers may change. Firstly, this article reviews the literature focused on scalable localization systems utilizing UWB technology. Then, a simulation model is developed in Matlab to study the system’s scalability for Two-Way Range (TWR) localization approaches. The model considers signal collisions with a given tag localization time intervals, as well as changes in the number of tags and Autonomous Guided Vehicles (AGV)s, where each AGV is equipped with only one anchor. Our model does not account for signal propagation models in the environment, assuming all signals propagate under line-of-sight conditions. Next, an overview of models that could be used to enhance the scalability of LoT systems is presented, along with software tools applicable for simulation in conditions closer to real-world environments. Conclusions are drawn on the need to implement the developed model into the Omnet++ system using an agent-based modeling library to incorporate tag localization while considering their movement.