# Feasibility Analysis of a LoRa-Based WSN Using Public Transport
## 1 Introduction
Among the others, we have: Sigfox [18], which offers longer-range communication with respect to LoRa but has service subscription costs; NarrowBand IoT [19] (NB-IoT) that differs with respect to LoRa since it is a cellular, and then SIM-based technology [20]. Other technologies are also Weightless, 5 by5 Wireless, HaLow, and so on. Among the main advantages of LoRa with respect to traditional technologies, are its long-range capabilities (up to 15 km), battery life optimization, easy deployment, and robustness to interference [21]. These features make LoRa the ideal choice for a vast number of IoT applications. A detailed study about LoRa, including the report of different tests, is documented in [22] where some possible solutions for performance enhancements of a IoT network based on the LoRa technology are also proposed. While most implementations built with these technologies are single-hop networks used to connect only end-devices to gateways and relying on the Internet for the remaining part, there are examples of multi-hop networks based on LoRa. In [23], a multi-hop linear network is deployed, with nodes forming a line topology and packets travelling from a node to the next in the line. In [24], the focus is on the effects of concurrent transmission in a multi-hop network, in order to ensure network reliability. The proposed network has a very simple multi-hop structure with respect to other proposed solutions for IoT, including, among the others, clustering [25], adaptive clustering [26], and specific routing clustering algorithms [27]. However, we believe that the proposed approach, even if simple, is suitable for the application of a DMS using public transport. A future further extension of this approach to other vehicles, can be also used to improve address problem of interest, energy and physical-aware coalition formation and resource management in smart IoT applications [28; 29]. The Low-Power Wide Area Network (LPWAN) presented in this work is realized with LoRa technology, a wireless communication technology (working on free-of-charge unlicensed spectrum) that uses Chirp Spread Spectrum (CSS) modulation to encode information. The prototypical network includes three types of nodes, which differ in their role but not in their hardware. On the public transport vehicles, the sensor nodes are installed on the vehicles themselves; they transmit air-quality sensors' and weather-parameters sensors' data to the gateway, together with position, date, and time information. Gateways spread around the city receive the information and relay it to the supergateway, a central node which processes this information. The supergateway may display the data, keep track of the correct operation of end-nodes and gateways belonging to the network, reporting any possible malfunction. Figure 1 is an example of potential installation in the city of Turin, Italy. After a brief presentation of the LoRa technology (Section 2), we focus on the theoretical analysis of propagation performance (Section 3). We describe the networking solutions that could be properly adopted for the realization of a LoRa-based WSN using public transport (Section 4) and the software implementation (Section 5). Conclusions and outlooks are given in the last section.