A Survey on the Viability of Confirmed Traffic in a LoRaWAN <s> A. SMART CITY <s> Smart cities initiatives have been subject of discussion in various forums throughout the world. This innovation in urban infrastructure of cities and the impacts of intensive application of technology are still being identified and mapped. A fundamental aspect under technological viewpoint to make this novelty a reality, and most comprehensive as possible is related to communication networks. Concept of Internet of Things (IoT) only materializes through a combination of technologies based on private and public networks and the Internet as the main platform. Utilities companies have already started their participation in this process in sense that they are deploying smart grids using technologies like RF Mesh and PLC, being RF Mesh the most widespread in world markets. But it is necessary to insert smart grid projects in the context of smart cities and in its converging alternatives of communications infrastructure. This work explores an emerging technology named as Long Range Wide Area Network (LoRaWAN) and proposes that this is the current alternative best suited to the big scenario of IoT, in which smart grids are included, and also compares with the RF Mesh technology widely adopted for this application. <s> BIB001 </s> A Survey on the Viability of Confirmed Traffic in a LoRaWAN <s> A. SMART CITY <s> Low-power wide area networking technology offers long-range communication, which enables new types of services. Several solutions exist; LoRaWAN is arguably the most adopted. It promises ubiquitous connectivity in outdoor IoT applications, while keeping network structures and management simple. This technology has received a lot of attention in recent months from network operators and solution providers. However, the technology has limitations that need to be clearly understood to avoid inflated expectations and disillusionment. This article provides an impartial and fair overview of the capabilities and limitations of LoRaWAN. We discuss those in the context of use cases, and list open research and development questions. <s> BIB002 </s> A Survey on the Viability of Confirmed Traffic in a LoRaWAN <s> A. SMART CITY <s> Recent research on Low Power Wide Area Network (LPWAN) technologies which provide the capability of serving massive low power devices simultaneously has been very attractive. The LoRaWAN standard is one of the most successful developments. Commercial pilots are seen in many countries around the world. However, the feasibility of large scale deployments, for example, for smart city applications need to be further investigated. This paper provides a comprehensive case study of LoRaWAN to show the feasibility, scalability, and reliability of LoRaWAN in realistic simulated scenarios, from both technical and economic perspectives. We develop a Matlab based LoRaWAN simulator to offer a software approach of performance evaluation. A practical LoRaWAN network covering Greater London area is implemented. Its performance is evaluated based on two typical city monitoring applications. We further present an economic analysis and develop business models for such networks, in order to provide a guideline for commercial network operators, IoT vendors, and city planners to investigate future deployments of LoRaWAN for smart city applications. <s> BIB003 </s> A Survey on the Viability of Confirmed Traffic in a LoRaWAN <s> A. SMART CITY <s> Low-power wide-area networking (LPWAN) technologies are capable of supporting a large number of Internet of Things (IoT) use cases. While several LPWAN technologies exist, Long Range (LoRa) and its network architecture LoRaWAN, is currently the most adopted technology. LoRa provides a range of physical layer communication settings, such as bandwidth, spreading factor, coding rate, and transmission frequency. These settings impact throughput, reliability, and communication range. As IoT use cases result in varying communication patterns, it is essential to analyze how LoRa's different communication settings impact on real IoT use cases. In this paper, we analyze the impact of LoRa's communication settings on four IoT use cases, e.g. smart metering, smart parking, smart street lighting, and vehicle fleet tracking. Our results demonstrate that the setting corresponding to the fastest data rate achieves up to 380% higher packet delivery ratio and uses 0.004 times the energy compared to other evaluated settings, while being suitable to support the IoT use cases presented here. However, the setting covers a smaller communication area compared to the slow data rate settings. Moreover, we modified the Aloha-based channel access mechanism used by LoRaWAN and our results demonstrate that the modified channel access positively impacts the performance of the different communication settings. <s> BIB004 </s> A Survey on the Viability of Confirmed Traffic in a LoRaWAN <s> A. SMART CITY <s> Low-power wide-area network (LPWAN) technologies are gaining momentum for Internet-of-things applications since they promise wide coverage to a massive number of battery operated devices using grant-free medium access. LoRaWAN, with its physical (PHY) layer design and regulatory efforts, has emerged as the widely adopted LPWAN solution. By using chirp spread spectrum modulation with qausi-orthogonal spreading factors (SFs), LoRa PHY offers coverage to wide-area applications while supporting high-density of devices. However, thus far its scalability performance has been inadequately modeled and the effect of interference resulting from the imperfect orthogonality of the SFs has not been considered. In this paper, we present an analytical model of a single-cell LoRa system that accounts for the impact of interference among transmissions over the same SF (co-SF) as well as different SFs (inter-SF). By modeling the interference field as Poisson point process under duty cycled ALOHA, we derive the signal-to-interference ratio distributions for several interference conditions. Results show that, for a duty cycle as low as 0.33%, the network performance under co-SF interference alone is considerably optimistic as the inclusion of inter-SF interference unveils a further drop in the success probability and the coverage probability of approximately 10% and 15%, respectively, for 1500 devices in a LoRa channel. Finally, we illustrate how our analysis can characterize the critical device density with respect to cell size for a given reliability target. <s> BIB005
An area in which LoRaWAN deployments are highly suitable is smart city operations, as these involve a high amount of devices that transmit only a few times a day BIB002 , BIB004 . A smart city's network would include several thousands of sensors monitoring aspects of the city such as air and water quality, road conditions and traffic congestion BIB003 . These aspects could all make use of unconfirmed traffic, but others such as smart lighting and smart metering require acknowledgements for commands transmitted to the devices. Smart metering involves the remote monitoring and control of electricity, water or gas consumption and would involve thousands of devices in urban cities BIB005 . Smart meters are part of the large resource networks responsible for keeping the city functional. Worldwide, the electricity sector has increasingly been aiming to optimise and automate the generation, transmission and distribution of electricity through the creation of smart grids, with smart meters being involved in this process BIB001 . LoRaWAN is a strong contender to enable the installation of smart meters due to the urban ranges possible and the number of devices a single gateway can support BIB001 . Acknowledgements play an important part in allowing providers to use their smart meters to e.g. switch off a non-paying customer's electricity. LoRa's low power consumption makes it an attractive choice for smart city deployments as frequent battery changing would be difficult in several applications. The technology has also shown the potential to be combined with energy harvesters to e.g. not only monitor traffic flow but be powered from the vibrations generated by vehicles  .