Long Range (LoRa) is a technology widely used to build Low-Power Wide-Area Networks (LPWANs) that enables bidirectional transmission of data packets over long distances. Most suitable for Internet of Things (IoTs) applications, it enables the broad-range communication and enables transmission of small data packets over long distances. This technology is perfect for covering remote areas where other data networks are not available. The small amount of data exchanged can be limiting if complex processing is required to understand specific events happening around the devices. An image elaboration or video processing is an example. As of today this tasks are mostly available in the cloud. Recent developments in the field of artificial intelligence hardware have led to the emergence of a new generation of low-power hardware capable of carrying out inference on pre-trained models with good performance on the edge for a few watts. In this paper we investigate the use of LoRa technology in combination with Edge Artificial Intelligence computing and Blockchain to build an architecture enabling vehicle surveillance and control of large and remote areas.
1. Introduction
cult to solve. Imagine having to cover vast mountainous
or wooded areas, or in any case areas that are dificult
Over the past few years, interest in Low Power Wide to reach and are poorly or not at all covered by other
Area Area (LPWA) technologies has grown so much that types of networks [
SYSTEM 2021 @ Scholar’s Yearly Symposium of Technology, A LoRa receiver can decode transmissions 20 dB below Engineering and Mathematics. July 27–29, 2021, Catania, IT the noise floor [ 16], making very long communication " lorenzo.felli@isprambiente.it (L. Felli); distances possible, while operating at a very low power. alessandro.vizzarri@uniroma2.it (A. Vizzarri) LoRa transceivers available today can operate between (A.0V0i0z0z-a0r0r0i)1-8338-7957 (L. Felli); 0000-0002-6274-991X7 137MHz to 1020MHz, and therefore can also operate in © 2021 Copyright for this paper by its authors. Use permitted under Creative licensed bands. However, they are often deployed in CPWrEooUrckReshdoinpgs IhStpN:/c1e6u1r3-w-0s.o7r3g CCoEmmUoRns LWiceonsrekAstthribouptionP4r.0oIncteerenadtiionnagl s(CC(CBYE4U.0)R.-WS.org) ISM bands (EU: 868MHz and 433MHz, USA: 915MHz and 433MHz). The LoRa physical layer may be used cal sensors (such as temperature, lights, speakers), and with any MAC layer; however, Long Range Wide Area moving computing power closer to these sensors in the Network (LoRaWAN) is the currently proposed MAC. physical world makes sense. With collection and proLoRaWAN operates in a simple star topology. A LoRa cessing power now available on the edge, companies can transceiver has five runtime-adjustable transmission pa- significantly reduce the volumes of data that must be rameters: Transmission Power (TP), Carrier Frequency moved and stored in the cloud, saving themselves time (CF), Spreading Factor (SF), Bandwidth (BW), and Coding and money in the process. Image recognition and video Rate (CR). These parameters have an influence on the streaming are just the tip of the iceberg. Security camera transmission duration, energy consumption, robustness companies, for example, struggle to use cloud-based soluand range [17]. Transmission Power (TP). TP on a LoRa tions because real-time data and video streaming to the receiver can be adjusted between -4 dBm and 20 dBm in cloud is prohibitively expensive [19]. Autonomous cars 1 dB steps. Because of regulatory and hardware limita- need ofline functionality on the road [ 20], while AR/VR tions, however, this is often limited between 2 dBm and gaming companies maintain their brand credibility by 14 dBm. TP has a direct influence on energy consumption keeping their products resilient to lag using 5G networks and the range of the signal. Carrier Frequency (CF). CF or other technologies [21]. is the centre frequency, which can be programmed in steps of 61Hz between 137MHz to 1020MHz. Spreading Factor (SF). SF determines how many bits are encoded 4. Blockchain in each symbol, and can be set between 6 and 12. A higher spreading factor increases the Signal to Noise Ratio (SNR) and therefore receiver sensitivity and range of the signal. However, it lowers the transmission rate and thus increases the transmission duration and energy consumption. The SFs in LoRa are orthogonal. Consequently, concurrent transmissions with diferent SF do not interfere with each other, and can be successfully decoded (assuming a receiver with multiple receive paths).
Bandwidth (BW). BW can be set from (a fairly narrow) 7.8 kHz up to 500 kHz. In a typical LoRa deployment, only 125 kHz, 250 kHz and 500 kHz are considered. A wider bandwidth means a more spread-out and therefore more interference-resilient link. In addition, it increases the data rate, as the chips are sent out at a rate equivalent to the bandwidth. The downside of a higher bandwidth is a less sensitive reception, caused by the integration of additional noise. Coding Rate (CR). CR is the amount of Forward Error Correction (FEC) that is applied to the message to protect it against burst interference. Higher CR makes the message longer and therefore increases the time on air. LoRa transceivers with diferent CR, and operating in ‘explicit header mode’, can still communicate with each other, as the CR is encoded in the header.
Blockchain technology was introduced by a single
entity or group under the name of Satoshi Nakamoto in
2008 and the code of its implementation was published
a year later in 2009 in the document ‘Bitcoin: A
Peerto-Peer Electronic Cash System’ [
Bitcoin uses the public key infrastructure (PKI)
mechanism [
Inside each node there is a key-value database in which the blocks containing the transactions that have reached consensus will be written. Each node validates the new blocks. Although the search for the hash that satisfies the consensus called Proof of Work takes on average 10 minutes regardless of the network’s computational capacity, checking the correctness of these hashes is extremely fast. 3. Edge computing This method creates a linear chain of blocks on which all nodes agree (Figure 1). This chain of blocks is the public Edge computing refers to applications, services, and pro- ledger technique of Bitcoin, called Blockchain. cessing performed outside of a central data center and closer to end users [18]. The definition of “closer” falls along a spectrum and depends highly on networking 5. Application Scenarios technologies used, the application characteristics, and the desired end user experience. While edge applications In this section, we discuss several recent IoT applications do not need to communicate with the cloud, they may based on LoRa and LPWAN and analyze possible areas still interact with servers and internet based applications. for improvement. The studies will be broken down by Many of the most common edge devices feature physi- application type.
Health Devices) has gained traction. This technology enables continuous health monitoring of human vital signs in everyday life, even 24h per day. Clinical environments can also benefit from the innovative advantages of this technology minimizing interference and discomfort with patients’ daily lives. A low-cost LoRa health monitoring system was proposed by Lousado et al. [37]. The system is able to track diferent environment data to monitoring the health conditions of the elderly in their homes using LoRa technology and The Things Network cloud framework. The LoRa node was developed using an ESP32/LoRa microcontroller and collect various environmental sensors data on temperature, humidity, carbon monoxide, gas, and smoke. The results seem encouraging, succeeding in closed places to reach a communication range of 1.2 km. Dimitrievski et al. [38] address the dig
tial for the preservation and prevention of all natural environments. Within precision agriculture (PA) practices, proximity data collection is often accomplished by IoT devices that act as collectors of environmental information. Many studies are present about environmental monitoring platforms realized by exploiting LORA technology. Ali et al. [25] built an environmental monitoring platform by combining the features of LORA and ZigBee.
Leveraging the best wireless features of ZigBee and LoRa, Figure 2: Blockchain, IoT and LoRA main use cases they proposed a diversified communication system with smart features in a single loT system. Wang et al. [26] presented a wireless sensor network system dedicated for meteorological monitoring based on Long Range (LoRa) for real-time services such as agricultural production demand. Very interesting the study conducted by Chen et al. to monitor air quality by using a UAV (Unmanned Aerial Vehicle) and LoRa communication system [27].
Authors in [28] proposed a system for automated oil spill
detection by remote sensing. Nordin et al. implemented a
narrowband IoT-based hydrological monitoring system in
a lagoon environment [
idated with the emergence of IoT devices. These two areas have now become closely related concepts. Many ifelds of urban monitoring can be covered by IoT and LORA technology. Del Campo et al. [30] proposed the LoRa technology to monitor the power distribution on suburban area. Many studies address public lighting in a smart city context [31, 32, 33, 34]. One of the most interesting is presented by Pasolini et al [35]. They studied how to implement smart street lighting by comparing IEEE 802.15.4 short-range communication technology