The advantage of LoRa® is the technology´s long range capability. One LoRa network, composed of a small number of gateways can cover entire cities or a quite a few square kilometers. One RoRa gateway has a range between 2.5 and 20 kilometers depending on the available bandwidth.
The range highly depends on the environment and obstructions in a given location.
LoRaWAN™ is a Low Power Wide Area Network (LPWAN) technology to use wireless, battery operated „things“ (Sensors) in regional, national or global netzworks. LoRaWAN fulfills the main requirements of the Internet of Things (IoT), for example a secure bi-directional communication, mobility and localization. This standard provides a seamless, overall sensor interoperability in the IoT sector. Complex, local installations can be avoided. Users, Developers and the Management have the possibility to push and realize the IoT strategy.
The LoRaWAN network architecture is typically built in a star-shaped topology, in which gateways are the invisible bridge for the data transfer between sensors in the field and the central network server in the backend. Sensors send their small data packages over a direct, wireless connection to one or more gateways. These communicate via a standard IP connection with the network server. Each end-node communication is in general bi-directional.
Most sensors and IoT devices transmit only a small amount of data on a regular basis. The measurement data for a typical sensor contain usually only its ID and a numeric value. LoRa transmits these small data packages over up to 20km range and supports a package size of max. 256 bytes.
According to a study of Signal and Systems Telecom from October 2015, low-power wide area networks (LoRa) will transmit 45-55% of all predicted IoT transmission volumes in 2030. LoRa is clearly one of the leading future transmission technologies to enable smart applications and services in wide areas.
The communication between sensors and gateways is spread out on different frequency channels and data rates. The selection of the data rate is a trade-off between communication range and a message duration. Due to the spread spectrum technology, communications with different data rates do not interfere with each other and create a set of „virtual“ channels increasing the capacity of the gateway. LoRaWAN data rates range from 0.3 kbps to 50 kbps. To maximize both, battery life of the sensors and overall network capacity, the LoRaWAN network is managing the data rate and RF output for each sensor individually by means of an adaptive data rate (ADR) scheme.
LoRa sensors and IoT devices have a battery life of up to 10 years. The low energy consumption for a transmission makes LoRa devices very effective in areas with no power supply. This energy efficiency makes sensors very affordable and allows the installation of a large number of sensors for different applications.
The sensors in a LoRaWAN™ network are asynchronous and communicate when they have data ready to send wether event-driven or scheduled. This type of protocol is typically referred to as the Aloha method. In a mesh network or with a synchronous network, such as cellular, the nodes frequently have no ´wake up´to synchronize with the network and check for messages. This synchronization consumes significant energy and is the number one driver of battery lifetime reduction.
In order to make a long range star network viable, the gateway must have a very high capacity or capability to receive messages from a very high volume of sensors. High network capacity in a LoRaWAN™ network is achieved by utilizing adaptive data rate and by using multi channel multi-modem transceiver in the gateway so that simultaneous messages on multiple channels can be received. The critical factors effecting capacity are the number of concurrent channels, data rate ( time on air), the payload length and how often nodes transmit. The adaptive data rate also optimizes the battery lifetime of a sensor.
Currently, a LoRa Gateway can handle 100 messages of 25byte in one minute at a data package rate of 10%. At 1000 messages the error rate raises to 45%. Therefore, LoRa is not a short-term real-time solution, but perfectly supports sensors and applications with an update rate of more than one minute.
All LoRa transmissions are fully end-to-end encrypted using the common and highly secure Advanced Encryption Standard (AES). Security was a key feature from LoRa 1.0 on and is constantly improved by the LoRa Alliance and its partners.
It is extremely important for each LPWAN to ensure the data security. LoRaWAN™ uses two layers: One for the network and one for the application. The network layer ensures the authenticity of the node in the network, whilst the security layer of the application assures, that the network operator has no access to the application data of the end users.
The AES (Advanced Encryption Standard) encryption is used in combination with the IEEE EUI64 Identifier to guarantee a correct key exchange.
Further information about the LoRa data security structure can be downloaded: PDF