LoRa (Long Range), as its meaning suggests, is a communications system intended to be used to send data wirelessly for up to 15 kilometers. The difference of this technology with other wireless systems is its focus on low power consumption while keeping its long range. As such, it is part of the group of IoT standards and protocols. LoRa may refer to the physical layer protocol introduced by Semtech or LoRaWAN, a network layer protocol intended to be used for battery powered systems.
The physical layer protocol version of LoRa was acquired by Semtech from French company Cycle in 2012. The protocol utilizes chirp spread spectrum technology to send data over 915 (US) or 868 (Europe) MHz bands with alternates 169 and 433 MHz. Each LoRa transmission can carry up to 51 bytes for lower data rates and 222 bytes for higher data rates. The data rate peaks at about 50 kbps and a minimum 300 bps.
The LoRaWAN network protocol is built on the top of the LoRa physical layer protocol and is primarily used by low-power sensors for communication. A typical LoRaWAN consists of end-node devices (sensors), gateways, network servers and application servers. The sensors transmit data asynchronously through the gateways to a network server which then sends the data to application servers.
LoRa technology offers several advantages,
- The LoRa physical layer utilizes ISM bands 868 and 915 MHz — frequencies that are free to use anywhere in the world.
- LoRa devices consume very little power making it ideal for battery-powered devices
- It can transmit and receive data for up to 15 km in suburban areas and 5 km in urban areas.
The lower power consumption is made possible through ADR (adaptive data rate) that varies output data rate depending on payload coupled with chirp spread spectrum technology that effectively provides processing gain. In addition, the modulation technique, similar to frequency shift keying, allows the use of low cost but high power amplifiers.
Another advantage is its high network capacity. In LoRaWAN, a single gateway can accommodate 1000 end-node devices. And since LoRaWAN is now standardized, the technology is globally interoperable.
Basic features of LoRa are displayed in the following table (LoRa Vs LTE)
As already mentioned, a typical LoRaWAN setup contains three components:
- Network server.
Each component is defined by the LoRaWAN protocol specification established by the LoRa alliance.
End-node – These are the low-power or battery-powered sensors that send data to applications through LoRa gateways. They are mostly “things” such as trackers, gas monitors, fire detection modules, etc.
Gateway – these accepts data from the end-nodes and relays them to the network server. The communication between the gateways and the network server is often over 3G or Ethernet backhaul that allows for a bigger throughput. A LoRaWAN typically contains a multitude of gateways with each possibly receiving (from end devices) and sending (to network servers) the same data.
Network server – performs as the LoRaWAN manager. It is responsible for scanning and rejecting duplicate data and is also the one task to do security checks.
LoRaWAN end-devices are not linked to a specific gateway. This is in contrast with traditional cellular networks wherein each cell station is managed by a specific base station controller. In fact, LoRaWAN gateways are just link-layer relays that forward data to the network server. The gateways do add a couple of bytes to the payload — information on the quality of the radio reception. Gateways are transparent to end nodes; it is the job of the network server to choose the correct gateway for replying to end nodes if necessary.
Although it is still in its infancy, LoRaWAN, through the efforts of the Lora Alliance is already an acknowledged standard by telecommunication companies and IoT services providers worldwide. LoRaWAN has been deployed in more than 50 countries and counting with the latest addition being Australia. In fact, the “Land Down Under” chose LoRa technology as their primary IoT network infrastructure. It is projected that the number of countries that will be LoRaWAN equipped will double for the next five years.
Telecommunication giant Comcast has already established LoRaWAN in Philadelphia and is looking to expand to Chicago and San Francisco. The company will be utilizing LoRa unlicensed narrowband network for business solutions including waste management and GPS-less tracking. Other telecom companies, like Orange, are following suit. The French operator will be employing a LoRa-based roaming network in 2018.
The estimated annual growth rate of LoRa is 89%. This means that from the current $1 billion industry value, the technology will be worth $24.5 billion in the next four years. In line with this, the LoRa-enabled devices will surpass 700 million in the same time frame. These devices include actuators, GPS-less trackers, sensors, transceivers, wearables, or even smartphones. Note that LoRaWAN is a subset of LPWAN (low power WAN) but is undoubtedly it’s the main driving force for it. The success of LoRaWAN could also boost other low-power technologies like Sigfox, Nwave or Weightless.
To give you an idea of how impressive these numbers are, Zigbee, a popular home automation wireless technology, has an estimated annual growth rate of 72%. The number for Wi-Fi is about the same. Bluetooth probably has the highest growth rate among them: 132%. However, these and LoRa are not competing with such technologies as Zigbee, Wi-Fi, and Bluetooth because they are primarily short-range wireless protocols.
The growth of LoRa and IoT, in general, is undeniable and inevitable. Before LoRa there were three things that hinder the proliferation of the “Internet of Things” idea: device and battery capabilities, network traffic and security. These three are answered by the LoRa protocol. The mentioned adaptive data rate technology allows for more devices to be catered by the network while lessening the strain on power handling. Not to mention the transparency of gateways which conveniently allows bidirectional communication and broadcasting. Security is achieved through 128 AES encryption that is available on the application server, network server, and end device. LoRa has managed to become what an IoT protocol has to be: cheap, fast and secure.