# Smart City Pilot Projects Using LoRa and IEEE802.15.4 Technologies
## 2 Related Work  
Smart City-based electronic products and applications are gaining importance nowadays. They address, for instance, urban mobility, public transportation, e-governance, safety, security, public lighting and environmental monitoring. Such complex scenarios are currently investigated by the Research Community. With reference to IoT deployments in smart city scenarios, a survey on research opportunities and challenges is provided in [15], and authors [16] discusses enabling technologies, weaknesses and risks. A survey on technologies and smart city applications is also reported in [17]. One of the objectives of the smart city concept is to monitor, control and manage the resources, such as the electric power. At this regards, the starting point for many current smart city implementations in Europe is the public lighting system [18; 19]. Authors [20] focuses on the design of street light controllers to provide a reduction in power consumption and eventually a reduction in cost of public lighting. The paper provides an estimation of the energy saved but does not report about real values of the power consumption drop achieved through a real deployment, as done here. Moreover, in contrast to this paper, current literature dealing with smart public lighting either shows simulation results (e.g., [21; 22]) or presents the results of limited testbeds (few nodes) (e.g., [21; 23; 24]). As far as the adoption of the IEEE 802.15.4 technology in smart city scenarios is concerned, several papers are currently available. As an example, authors [25] discusses a simulator for evaluating the performance of IEEE 802.15.4 and IEEE 802.11 when applied to such scenarios. Authors [26] investigates the deployment of wireless sensor networks at road intersections in some of the world major cities. Using a propagation model that corresponds to the 2.4 GHz IEEE 802.15.4 technology and considering 52 city maps extracted from OpenStreetMap, the Authors show that the resulting graph is highly disconnected and comprises up to 25% of isolated nodes. However, in the above cited works and in most of the papers on this topic, either no experimental results are provided or very limited testbeds are investigated. As far as significant testbeds are concerned, one of the largest is Smart Santander [27], where around 3,000 IEEE 802.15.4 devices were deployed, which makes the size of such testbed similar to the one presented in this work. However, in contrast with this paper, authors[27] does not deal with smart lighting, thus no specific insight is provided on such application nor on the corresponding economic benefits. With regard to the adoption of LoRa in smart city scenarios, authors [28] presents a LoRaWAN demonstrator to be deployed at the Scientific Campus of the University of Lille. Prior to the installation of the LoRaWAN network, a field study was carried out to explore the link-level performance of such technology. Tests were conducted in both outdoor and indoor environments using only one gateway and showed that LoRa provides good performance over the major part of the Campus. However, neither capacity nor packet success rate were evaluated in the paper. In [29] the authors compare via experimentation the link-level performance obtained with the LoRa proprietary modulation and with an FSK (Frequency Shift Keying) modulation. Experiments are performed in an urban environment and results suggest the superior performance of LoRa over FSK under adverse transmission conditions. Authors [30] studies the performance of a LoRa-based IoT network in a typical urban scenario. The Authors provide simulation results showing that a LoRa network can scale well, thanks to the possibility to use multiple gateways and be equipped with different radios, capable of receiving signals transmitted with different spreading factors at the same time. Finally, authors [31] shows results obtained through the NS-3 network simulator, where the bit error rate, together with the LoRaWAN MAC protocol, are modelled.