# Smart City Pilot Projects Using LoRa and IEEE802.15.4 Technologies
###### Abstract
This topology is adopted by most Low-Power Wide-Area Networks (LPWANs), which are especially designed to interconnect battery-powered devices with low bit rates over long ranges. Due to their low cost, wide coverage and straightforward setup, LPWANs are actively considered by academia and industry as the future wireless communication standard for IoT. Indeed, according to [8], by 2025 almost half of wide area IoT connections will be supported by LPWANs. LPWANs operate on both unlicensed and licensed frequency bands and include proprietary and open standard options, among which the most relevant are LTE Cat-M1 [9] (also known as LTE-M), LTE Cat-NB1 [10] (also known as NB-IoT), FlexNet [11], LoRa [12], Sigfox [13] and Telensa [14]. In particular, LoRa will be the first LPWAN technology to break the milestone of 100 million connections, by the end of 2018 [8]. Both the above discussed solutions (short-range and long-range communications technologies with mesh and star topologies, respectively) are addressed in this paper, which presents the implementation of two smart city testbeds developed in Italy. The first one was developed in 2012 by the Wireless Communication Laboratory at the University of Bologna -WiLAB-, and operated until 2014 in the framework of the PEGASUS project. It consisted of the realization of a mesh topology (implemented on top of the IEEE 802.15.4 standard) of _enhanced_ street lamps, which enabled smart services such as smart lighting, smart parking, vehicle-to-roadside communications and telemetering. The choice of the mesh network topology, along with the IEEE 802.15.4 short-range technology, is motivated by the regular deployment of light poles, usually at short distance one to the other. A successive real-world, large-scale implementation, which counts around 3000 street lamps installed in the Italian municipality of Montechiarugolo, is also presented in this paper. To the best of the Authors' knowledge, this is the first paper showing a large-scale wireless network of street lights, which is fully operational since 2014. The second testbed concerns with the implementation of a LPWAN in the framework of the RIGERS project, carried out with the support of the municipal council of Bologna, which is aimed at building-monitoring applications. In this case, the adoption of the IEEE 802.15.4 would be highly critical because of its reduced coverage, coupled with the difficult propagation conditions of indoor environments (nodes are placed inside apartments, which has a detrimental impact on the connectivity owing to the limited link budget of the IEEE 802.15.4 technology). For this reason, the long-range LoRa technology, which exhibits a high receiving sensitivity, has been chosen, along with the star network topology. The project is still ongoing and this paper reports about: (1) the results of the measurement campaigns carried out in two different districts of the city of Bologna to estimate the related path-loss models; (2) the network-level performance obtained through a simulator incorporating the estimated path-loss models. Apart from providing the technical details of the two testbeds and discussing their performance through experimental results and simulations, in this paper we want to highlight that, although addressed at the same urban scenario, IoT-based services as those considered here could require different technologies and network topologies in order to be effective. Indeed, owing to their differences (number of nodes, nodes layout, propagation conditions, etc.) the two testbeds are somehow orthogonal. The paper is organized as follows. In Section 2 an overview of related work is provided. In Section 3 the communication technologies adopted in the testbeds are introduced. In Section 4 the smart lighting testbed is described, whereas the RIGERS project is discussed in Section 5. Final conclusions are drawn in Section 6.