# A Smart Parking Solution Architecture Based on LoRaWAN and Kubernetes
## 2 Related Works
In [16], a sensor collects the status of a parking lot. The data collected are passed to a microcontroller. The microcontroller forwards the data to a network server through a gateway. At last the network server forwards the data to the application server. The protocol used for communication between the microcontroller and the network server is User Datagram Protocol (UDP), while the communication made on the network server is through the MQTT protocol. In the application server the state of the battery and the parking lots data are shown in real time through a dashboard. The authors in [17] use sensors for detecting the occupancy of a parking lot. A microcontroller recollects all the data from the sensors and forward to the MQTT Server over WI-FI. The MQTT server forwards the recollected data to a platform that will process and store the received data. In addition, the platform provides a user interface for letting the users reserve a parking lot. It also bills the users for the reservation time of a parking lot. The users are given an RFID card along with a unique login credentials for accessing to parking lot and being identified, respectively. Solution presented in [18] describes a system that uses sensors that send the occupancy information to an information center via Zigbee. This solution also handles a Bluetooth station used to locate users inside the parking lot. It helps users to find the shortest path to an empty slot using a proposed \"Shortest path search algorithm\". All the gathered information is sent to over Wi-Fi to a parking management menu. The number of information centers will grow proportionally to the size of each parking lot where the solution is implemented. Likewise, the solution proposed in in [19] uses Zigbee and Wi-Fi. This last solution in addition, uses an IoT Middleware Layer using RESTful communication so it enables data retrieval from external entities. Real-Time Smart Parking Systems Integration in Distributed ITS for Smart Cities [20] describes a solution for a Distributed Intelligent Transportation System (ITS). The architecture considers the data flow from the edges of the system towards distributed gateway architecture, where the intelligence and storage are distributed across limited geographical areas to avoid some limitations. This architecture is highly scalable since the addition of new components of the system is automatically accommodated by a proportional increase in the number of gateways. For the parking lot system component, the solution works with any kind of detection system since the architecture was built thinking on a highly scalable factor. Collected information is sent to a determined gateway so it can be further processed and sent or presented directly to end-users. Zigbee is another technology widely used for smart parking, as presented in [21]. A Zigbee router covers each parking slot. The information is sent through a multi-hop network to the Coordinator. It transmits the information to the Smart Gateway which analyzes and joins it with the parking slot position, sending it to the Central Server. Finally, the information received feeds two mobile applications: Parking app (users) and Policeman app (traffic cops). The solutions provide a payment feature using NFC in the smart gateway and smartphone. Node Based Architecture for IoT is shown in [8]. In this solution, the end-node is an ultrasonic sensor that collects the information. An Arduino Uno is the processing node that connects and sends the information to the cloud server through an ESP8266-01 Wi-Fi Module. The Server feeds the desktop and mobile applications. It brings the possibility to search for parking slots, booking a place and guide the user to it. In terms of sensor and smart parking system communication, several solutions are proposed. Most of them are focused on wireless communications because they are easy to implement and cheap. Solutions like [8,11,15,22] make use of Wi-Fi technologies for sensor communications.