## 4 LoRaWAN-Based Outdoor Positioning in Application-Specific IoT Domains
### Smart Transportation (Intelligent Transportation)  
With the growth of cities, the scale of the transportation system of cities has become large that leads to uncontrolled growth in traffic volume. The caused problems by increased traffic can be divided into three categories: traffic congestion (delay and fuel prices increment), safety (accidents and emergencies), and pollution (air pollution increment) [115]. IoT development has become a new opportunity for the elimination of transportation problems by introducing smart transportation [116]. Smart transportation develops a wide variety of sensors to gather information about the roads, vehicles, and drivers. Using these data, transportation servers locate vehicles and determine the best route for problem reduction. For efficient development of smart transportation, authors in [117] proposed six different categories of sensors (safety, diagnostic, traffic, assistance, environment, and user) that can divide into two parts of in-vehicle sensors and road sensors. Effective use of sensors greatly depends on adopted wireless communication technology. The authors in [118] proposed a vehicle-to-everything (V2X) communication architecture with LoRaWAN wireless technology. The authors mentioned that LoRaWAN plays an important role in developing and solving fundamental challenges such as reliability, data handover, time criticality, modularity, and energy efficiency with vehicles on the move for V2X. Performance of LoRaWAN schemes with different parameter configurations for V2X is evaluated and compared in [119]. The authors mentioned that higher BW and lower SF parameter configurations should be selected to resist the fast fading caused by the Doppler effect. Localization Methods in Smart Transportation  
One of the most popular categories of LoRaWAN base localization is vehicle monitoring, locating, and tracking. In this category, embedded sensors communication in vehicles is used for localization. This is useful for problems avoidance such as congestion. Commonly used methods for localization have limitations such as coverage, availability, and operational cost. The authors in [120] mentioned that the availability of communication networks is an important part of the vehicle positioning system and the communication will be lost for the area which is not covered by the cellular network. To overcome this problem, they proposed the Integration of LoRa-Cellular (ILC) using hybrid communications to trace a vehicle position. The decision on which network is used for communication is decided based on the RSSI level and energy consumption. The authors in [121] developed a transit vehicle tracking service prototype based on an Intelligent Transportation Systems (ITS) architecture to evaluates the operation of LoRaWAN technology in a transit vehicle tracking service in a medium-sized city. They investigate optimal LoRaWAN configuration parameters (SF, BW, and CR) for the service. The authors in [122] proposed a real-time bus positioning system based on LoRaWAN technology which can help people to identify the dynamic location of buses and the expected arrival time. The proposed system is composed of terminal devices, data concentrators, cloud servers, and a user interface. The evaluation of the method show wide coverage, low loss rate, low power consumption, and low cost. The authors in [123] propose an IoT-based bus location system using the LoRaWAN concept. In the proposed method, the location information of the bus is collected and distributed using the LoRaWAN network. In addition, they propose the use of smart bus stops using electronic paper, which has the characteristics of excellent outdoor visibility and low power consumption. The authors in [124] proposed the development of an IoT-based public vehicle tracking system, using LoRaWAN and Intelligent Transportation Systems services. As a proof of concept, the authors designed and executed some experiments based on the proposed method.