# A Smart Parking Solution Architecture Based on LoRaWAN and Kubernetes
## 2 Related Works
These solutions present multiple limitations like signal range and energy consumption in contrast with other technologies like IEEE 802.15.4 (i.e., LoRaWAN) that are wide-range coverage and low power consumption. Even though Wi-Fi offers greater data rates, this is not considered a strength since sensors should not send a lot of data in a short time. On the other side, technologies based on IEEE 802.15.4 are lighter, so they require little processing power. As for technologies based on IEEE 802.15.4, there are several IoT-oriented protocols adopted. Solutions such as [18,19,21] use ZigBee for sensor communication. It only presents a drawback; the range of coverage is shorter compared to other IEEE 802.15.4 technologies; despite its ability to send long-distance messages using a mesh topology. Some solutions like [14,16,20] make use of LoRaWAN because of the low power consumption; a feature that enhance battery duration, and a range comparable to cellular communication technologies. The only disadvantage of technologies based on IEEE 802.15.4 is low data rate, but IoT devices does not require huge data rates. Infrastructure showed in [11] uses Wi-Fi Access points (AP) to gather information from each sensor of for each determined section. This information is sent to every Local parking management system and uploaded to the Central Parking Management System (CPMS). This infrastructure uses more communication resources and needs more hardware devices per parking lot. Hence, it can become too expensive depending on the size of the parking lot facilities. In [20], authors explain the benefits of local data processing before arriving at the control center. This architecture provides greater reliability, confining faults within each gateway while the rest of the system continues to operate. In [23] local data processing is performed to optimize the monitoring of parking spaces. In our implementation, the data is processed before being stored in the NoSQL repository. This is mandatory since the data collected by the sensors have unnecessary additional information and processing it reduces its size and increases their informational value. In this implementation the data are stored in a NoSQL repository for the versatility it offers, the system generates a large amount of data that must be recorded. The horizontal growth that characterizes this kind of repository is adapted to the cluster of Kubernetes implemented in the system with new nodes that could be implemented to balance the load. In addition, it does not require a large amount of resources to operate. The most well-known approaches for sending sensor's collected data are through MQTT protocol, HTTP protocol and directly to a database. MQTT stands for Message Queuing Telemetry Transport and it is one of the best ways to send data from a WSN network, since it is designed for networks with high latency and low bandwidth. Another advantage of MQTT is the existence of levels of quality of services which ensures high delivery guarantees. In [8,15,23] they make use of an MQTT broker which implies that the size of the packets and power consumption are less than implementation. In [5], the solution proposed uses the HTTP protocol for sending data from the gateway to the server. However, the use of this protocol generates additional metadata that is not useful for IOT implementations. In [24], the implementation sends the data directly to the database. This data are not processed and the database is vulnerable to injection attacks. Implementations with this approach are less likely to escalate over time because making repeatedly database connections involves high latency in the system. Therefore, adding new parking lots to the system could result in low quality service. Similarly, in [15], sensors are connected wirelessly via Wi-Fi to a raspberry pi that acts like an intermediate between this and the cloud. This infrastructure uses an IBM MQTT server that allows the mobile application to connect through a secure channel and a 2-factor authentication.