A Crowd Monitoring Methodology based on the Analysis of the Electromagnetic Spectrum

Abstract

In this work, a system able to monitor the crowd density detecting mobile phone communications through the analysis of the electromagnetic spectrum is proposed and experimentally assessed. The variations of the electromagnetic spectrum are collected with a low-cost spectrum analyzer, and a high gain log-periodic directive antenna (LPDA). The objective is to relate the spectral power density in a given frequency band to estimate the connections present and the number of people in a given area. In particular, a linear regression estimator, whose parameters have been calculated with the least square method modeled considering experimental data in a controlled environment, permits us to infer the number of customers detected on a given frequency band. The obtained experimental results demonstrated the efficacy of the method, which can be used not only to monitoring the number of people in a given scenario, but it also be used for commercial activities to detect the presence and pervasiveness of different mobile phone companies.

Monitoring Large Crowds With WiFi: A Privacy-Preserving Approach

“…Another bleeding-edge approach is the monitoring of the electromagnetic spectrum [13]. This solution is noncooperative and consists in monitoring frequency bands used by telco operators and their customers to make calls, send text messages and have mobile internet access.…”

“…Moreover, tens of nodes are necessary to monitor a single room (they installed approximately one node per 15 to 40 square meters based on [15,Fig. 2,13,and 24]). Besides, their counting errors are higher than ours: Results in [15,Fig.…”

“…Moreover, [20] has not been tested for areas hosting hundreds of individuals. The work [13] has sometimes better accuracy and sometimes worse accuracy than the present counting system; it also has not been tested on crowds of more than 100 people (see [13,Fig. 6]).…”