Nowadays, cities are places where data streams are continuously and ubiquitously exchanged between smartphones, IoT devices, and other modern technologies. The constantly growing urban populations make it necessary to provide stakeholders like transportation managers and security agencies with accurate methods for crowd-monitoring. In this way, more efficient space construction processes can be designed, i.e., by optimizing resource allocation or enhancing security measures. Analyzing network traffic has proven to be an effective method to estimate people’s presence in various specific areas. This thesis aims to provide a complete understanding of WiFi-based crowd-monitoring techniques, with their main advantages and drawbacks. We conducted an extensive experimental study of WiFi 802.11 probe requests, searching for new valuable information to enhance these systems’ performance and overcome their main limitations.