LoRaWAN and LoRaMesh

LoRaWAN and LoRaMesh

What is LoRaWAN?

LoRaWAN is one of the low power wide area networks (LPWAN) that in recent years have received significant attention in the research community. It offers low-power, low-data rate communication over a wide area network ranging between 15–20 km which are quite necessary for the implementation of better IoT technologies. In the case of these networks, we first intend to look into aspects related to their architecture, later divulge into the efficient ways to operate, the components required and their benefits and protocols.

LoRaWAN Network Topology

LoRaWAN’s network is a single-hop star topology that consists of end-devices that transmit data directly to gateways. The star topology helps to increases battery lifetime when long-range connectivity is used. These networks need to operate efficiently hence one will need a network server to manage all gateways and allow the devices to securely communicate with the cloud. This communication between the end node and gateway is bi-directional. The communication when an end node transmits data to the gateway is called an up-link and when the gateway transmits data to the end node is called a down-link.

This network server’s main responsibility is assuring the security, data routing and battery optimisation of the end nodes. Its stack is built up of multiple loosely coupled components to maximise flexibility and scalability. The LoRaWAN stack can be hosted on-premise or in your private cloud, it depends on one’s choice between full service and full control.

The core components of the stack are:

• the gateway server:

The gateway server manages the gateways and creates secure connections with the network server.

• the network server:

The network server implements the LoRaWAN protocol, the core of the network layer management. It de-duplicates up-links, selects the gateways used for down-links and sends ADR commands to optimise the data rate of devices.

• the joint server:

The Joint server is the component responsible for storing the root keys of the devices. It uses the root keys to generate session keys used by the network server and application server. One can even run the joint server separately.

• the application server:

The application server is responsible for the decryption of the received sensor data and encrypts data centres to the end devices. It is from the application server that one can easily link their own data management system or quickly launch template integrations with the Cloud platforms of AWS, Azure and Google cloud.

• the identity server:

The identity server registers users, applications, devices and gateways. This allows you to run a scalable multi-tenant network distributed over multiple regions around the world.

The main components are end node, gateway, network server and application server which plays the major role in development of minimalistic LoRaWAN network. It can be seen in Fig 1.

The LoRaWAN, NB-Iot WAN and Sigfox are all part of the large family technologies known as Low Power Wide Area Network (LPWAN). Fig 2. represents the comparison between these three based on range, coverage area, deployment, cost efficiency, battery life, QoS, Payload Length, Latency Performance and scalability. These aspects are important when we investigate the best network according to its usage and desired output efficiency.

LoRaWAN protocols

The LoRaWAN protocols are defined by the LoRa Alliance. It is a non-profit organisation of more than 500 member companies, committed to enabling large scale development of LPWAN IoT through the development and promotion of the LoRaWAN open standards.

LoRa is an acronym for long range, and it is a wireless technology where a low powered sender transmits small data packages (0.3 kbps to 5.5 kbps) to a receiver over a long distance. A LoRa device (end node) has a wireless transceiver. If sensors would be added to this device, this device can act as a remote sensor. The protocol does not support direct communication between end nodes. In the case of direct communication between LoRa devices without the use of a gateway, Radio-Head Packet Radio Library can be used for embedded microprocessors.

Applications of lora

LoRaWAN networks are majorly used in the construction of smart cities, smart grids (smart metering) and IoT. In the case of smart metering, it can be used to create a mesh network. It is a novel modulation technique that enables it to communicate over long distances and it has over 50 communication channels. Stars-of-stars topology can be implemented in urban areas where gateways can be placed in convenient places. However, in rural areas where gateways cannot be placed at required locations due to the unavailability of a reliable communication infrastructure the usage of mesh topology in such situations allows for flexible placement locations for gateways, and allows for a large coverage of an area.

Mesh architecture helps to increase the range of the LoRa network. LoRa based infrastructure can be deployed and operated at a lower cost compared to previously discussed technologies, thus depicting the limitation of previously discussed communication methods regarding smart metering. Using mesh configuration, rather than installing additional nodes for hard-to-reach places, allows intermediate nodes to be used to relay information to the gateway. A LoRa mesh based smart metering system will form an interconnected mesh of smart meters. When there is a connection between a smart meter and a gateway, it directly sends the data to the gateway otherwise it uses intermediate nodes to connect to the gateway. To extend the range of the communication network in remote areas for smart metering, the LoRa mesh network is proposed and studied. The authors propose algorithms that can be implemented in node and gateway hardware for efficient communication within the remote MG’s. The LoRa devices in a mesh network are then simulated and verified, which meets the required specifications for smart metering purposes. The LoRaMesh network is represented in Fig3.

Due to differences in usage of both the networks, the comparison between them can be spotted in Fig4., except from that the urban area range and rural area range for mesh network is 3–5 km and 10–15 km respectively, for WAN network is 2–5 km and 10–15 km respectively.