In increasingly interconnected big cities, frequency bands of 2.4 and 5 GHz play an essential role in various wireless applications, such as Wi-Fi (IoT devices), home automation, and media streaming. However, densely populated urban environments, such as Guayaquil-Ecuador, pose a critical challenge in efficiently managing these spectrum bands for future applications in smart and sustainable cities. The lack of comprehensive studies on interference in these bands in dense indoor environments undermines the reliability of networks. Therefore, this affects the ability to use higher modulation schemes (MCS), which is essential for applications that require higher connection speeds. In this context, this study focused on collecting radio spectrum measurements in downtown of Guayaquil, specifically in the 2.4 and 5 GHz bands. This paper aims to create a probabilistic model that characterizes the statistical properties of interference in the specified frequency bands (2.4 GHz and 5 GHz) within densely populated urban areas. This model is valuable for analyzing and optimizing wireless channel capacity in such environments for future applications of IoT devices in smart cities.