# An IoT-Based Participatory Antitheft System for Public Safety Enhancement in Smart Cities
## 4 Performance Evaluation and Discussion  
During the experimental tests performed it was considered that line of sight or partial line of sight were maintained for the range test. The most adverse condition was the likely presence of few Wi-Fi networks in the area and vehicles travelling along the street. Actual results for many applications may vary. However, the test performed demonstrates that it is possible to maintain a range of up to 300 m, far greater than the range of most modern Bluetooth applications. Figure 12: TL ANT2409A 9 dBi gain antenna. Figure 13: iBLio BLE module connected with 2 dBi gain antenna. could improve the achievable range. In almost all measurement tests, the coverage distance was measured in mainly line of sight conditions. Additionally, changes could be made to the layout of the PCB, to increase the distance from the copper plating and the antenna, however, this would require the size of the node to increase. The range could be potentially extended by using a point-to-point network with repeaters. Current consumption during advertising mainly depends on the advertising interval, which is adjusted by modifying the relevant parameter. Practically, in order to save current, it the device should advertise periodically and not continuously. The measurement setup that was used for measuring the current is schematically shown in Figure 16, while the lab devices are depicted in Figure 17 and the measurements diagram is illustrated in Figure 18.  
It was found that current consumption was approximately equal to 36 mA, which is quite close to the value found by the device manufacturer [50] regarding current consumption in advertising mode with advertising interval 1000 ms, 31 bytes payload, and 4 dBm output power. In order to reliably evaluate the effectiveness of the proposed sensor platform, to fine tune sensor/smartphone software parameters, and to evaluate the overall performance of the system proposed, a two months pilot survey with several participants was conducted at certain pilot sites [35]. Specifically, the City.Risks consortium has organized two test sessions in two capital cities (i.e., Rome and Sofia) to check the functionality of the proposed system in real environments [51]. The tests performed in Rome, took place in December 2017 in Circo Massimo and in Aventino. First, in Circo Massimo, which is an area free of buildings, a small group of citizens was involved in the test, together with representatives of the Municipal Police and some members of the City.Risks consortium. Specifically, there were four different teams of participants in the field: the \"victims of theft\", the \"thieves\", the \"policemen\" and the \"community activists\". The City.Risks Operation Center was established at the Municipal Police headquarters of Rome. In the tests performed, the first type of participants were equipped with some BLE sensors, previously registered on their smartphones and started wandering around in the area. After a while, they were approached by some of the second type of participants, who \"stole\" the BLE tags and moved away. The thefts were reported to the members of the Operation Center, who activated the stolen tags so that they could be tracked by the community activists. The pieces of information collected by the smartphones were sent to the Operation Center and eventually the policemen \"arrested\" the \"thieves\" and retrieved the stolen tags. Next, in the Aventino residential area, the same scenario was executed to simulate the effect of blocking buildings on the BLE signals. Once again, the \"stolen\" tags were retrieved. The pilot tests conducted in Sofia, took place in February 2018 inside The Mall shopping center. In these tests some citizens participated playing all of the aforementioned roles. Three gateways were placed in different locations inside the mall, to detect the stolen tags. These pilot tests gave the opportunity to evaluate the functionality of the system indoors.