Friday, October 5, 2018

LoRa and LoRAWAN - Fundamentals of IoT (Part 2)

LoRa (Long Range) is a patented digital wireless data communication IoT technology developed by Cycleo of Grenoble, France. It was acquired by Semtech in 2012, which holds the IP for LoRa transmission methodology.
LoRa transmits over license-free sub-gigahertz radio frequency bands like 169 MHz, 433 MHz, 868 MHz (Europe) and 915 MHz (North America). LoRa enables very-long-range transmissions (more than 10 km in rural areas) with low power consumption.
The technology is presented in two parts — LoRa, the physical layer, and; the communication protocol built upon the underlying LoRa physical layer. The communication layer may be LoRaWAN (Long Range Wide Area Network), an open source communication protocol defined by the LoRa Alliance consortium; or may be Symphony Link, another open source communication protocol defined by a company called Link Labs.
Thus, LoRaWAN™ defines the communication protocol and system architecture for the network, while the LoRa® physical layer enables the long-range communication link. LoRa WAN communication protocol ensures reliable communication, secure communication and adds additional headers to the data packets.

LoRa and LoRaWAN

The LoRaWAN communication protocol is defined by the LoRa Alliance, a non-profit technology alliance of more than 500 member companies, committed to enabling large scale deployment of Low Power Wide Area Networks (LPWAN) IoT through the development, and promotion of the LoRaWAN open standard.

The first LoRaWAN standard was announced by the LoRa Alliance in June 2015. In 2017 LoRaWAN specification 1.1 was released.

LoRa and LoRaWAN permit inexpensive, long-range connectivity for IoT devices in rural, remote and offshore industries. They are typically used in mining, natural resource management, renewable energy, transcontinental logistics, and supply chain management.

LoRaWAN is the most adopted type of LPWAN, and promises ubiquitous connectivity in outdoor IoT applications, while keeping network structures, and management, simple.

LoRa and LoRaWAN Network Topology

LoRaWAN network architecture is deployed in a star-of-stars topology (vs. mesh topology eg. Zibgee).

The LoRaWAN networks laid out in a star-of-stars topology have base stations relaying the data between the sensor nodes and the network server.
Communication between the sensor nodes and the base stations goes over the wireless channel utilizing the LoRa physical layer, whilst the connection between the gateways and the central server are handled over a backbone IP-based network.
  • End Nodes transmit directly to all gateways within range, using LoRa.
  • Gateways relay messages between end-devices and a central network server using IP.

End NodesThe End Nodes are LoRa embedded sensors. The nodes typically have,
  • Sensors (used to detect the changing parameter eg. temperature, humidity, accelerometer, gps),
  • LoRa transponder to transmit signals over LoRa patented radio transmission method, and
  • optionally a micro-controller (with on board Memory).
The sensors may connect to the LoRa transponder chip, or the sensor may be an integrated unit with the LoRa transponder chip embedded.

It is possible to program the micro-controllers in micro-Python or micro-Javascript. This allows developers to use the data from sensors like accelerometers, temperature, etc. and implement certain use cases eg. Fall detection algorithms may be implemented by programming the micro controller based on the inputs from the accelerometer and other sensors.

The LoRaWAN end nodes(sensors) typically use Low Power and are battery powered (Class A and Class B). LoRa embedded sensors that run on batteries that can typically last from 2–5 years. The LoRa sensors can transmit signals over distances from 1km — 10km.

GatewaysThe LoRa sensors transmit data to the LoRa gateways. The LoRa gateways connect to the internet via the standard IP protocol and transmit the data received from the LoRa embedded sensors to the Internet i.e. a network, server or cloud.
The Gateways devices are always connected to a power source. The Gateways connect to the network server via standard IP connections and act as a transparent bridge, simply converting RF packets to IP packets and vice versa.

Network ServersThe Network servers can be cloud based platform solutions like The Things Network (TTN) or LoRIOT. The network servers connect to the gateways and de-dup data packets, and then routes it to the relevant application. The network servers can be used for both uplink (i.e. sensor to application) or downlink (i.e. application to sensor) communication.
The Things Network Network server has a Router, Broker and Handler, which processes the data packets from the LoRaWAN gateway. It also has an AWS Bridge that connects TTN to the AWS IOT platform.

Application Servers
The Application can typically be built over IoT platforms like AWS IoT using Lambda, DynamoDb or S3 services.

For earlier information ,visit 

LPWAN - Fundamentals of IoT (Part1)

Source: Internet


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