LoRa

LoRa

SX1278, a LoRa module
Developed by	Cycleo, Semtech
Connector type	SPI/I2C
Compatible hardware	SX1261, SX1262, SX1268, SX1272, SX1276, SX1278
Physical range	330 kilometres (210 mi) in perfect conditions.[1] Approximately 10 kilometres (6.2 mi) in practical conditions

LoRa (from "long range") is a physical proprietary radio communication technique based on spread spectrum modulation.^[2] It is used as the physical layer for LoRaWAN, a low-power, wide-area network (LPWAN) protocol that wirelessly connects battery-operated devices to the Internet. LoRa can be thought of as the radio signal technology (similar to Wi-Fi or cellular), while LoRaWAN is the protocol and network architecture that manages communication over that signal.^[3]

Together, LoRa and LoRaWAN provide a solution for connecting low-power devices over long distances, making them a key technology for the Internet of Things (IoT). The technology is primarily used for applications where small amounts of data need to be transmitted infrequently from hard-to-reach locations, such as in smart agriculture, industrial monitoring, and asset tracking.^[4] The technology was originally developed by the French company Cycleo, which was acquired by Semtech in 2012, and the LoRaWAN standard is now managed by the LoRa Alliance.^[5]

LoRa uses license-free sub-gigahertz radio frequency bands EU433 (LPD433) or EU868 (863–870/873 MHz) in Europe; AU915/AS923-1 (915–928 MHz) in South America; US915 (902–928 MHz) in North America; IN865 (865–867 MHz) in India; and AS923 (915–928 MHz) in Asia;^[6] LoRa enables long-range transmissions with low power consumption.^[7] The technology covers the physical layer, while other technologies and protocols such as LoRaWAN cover the upper layers. It can achieve data rates between 0.3 kbit/s and 27 kbit/s, depending upon the spreading factor.^[8]

LoRa devices have geolocation capabilities used for trilaterating positions of devices via timestamps from gateways.^[9]

LoRa devices have geolocation capabilities used for trilaterating positions of devices via timestamps from gateways. This feature, combined with the technology's long-range and low-power characteristics, makes it suitable for a wide range of Internet of Things (IoT) applications where assets are dispersed and battery life is critical.^[10]

LoRaWAN is widely used for asset tracking, particularly for non-powered assets that require a tracking system with a long battery life. Because it does not rely on cellular networks, it is an effective technology for monitoring moving objects in areas with poor or no GSM signal, such as in remote areas or inside large metal shipping containers.^[11] A common application is in the track and trace of construction and railway equipment. For example, LoRaWAN trackers are used in Switzerland to monitor the location of construction wagons, providing security against theft and improving the efficiency of fleet logistics.^[12]

In precision agriculture, LoRaWAN sensors are used to create managing information systems that optimize farming operations. Low-power sensors are deployed across large fields to monitor soil moisture, temperature, and nutrient levels, allowing for more efficient irrigation and fertilization. The technology is also used for tracking the location and health of livestock.^[13]

LoRaWAN is used for smart city applications. Municipalities use it for a variety of services, including:

• Smart metering: Utility companies deploy LoRaWAN-enabled meters to automatically read water and gas consumption without needing to send a technician.
• Waste management: Sensors in public trash bins can report when they are full, allowing for the optimization of collection routes.
• Smart parking: Sensors in parking spaces can detect whether a space is occupied, providing real-time data to drivers via a mobile app.

LoRa uses a proprietary spread spectrum modulation that is similar to and a derivative of chirp spread spectrum (CSS) modulation. Each symbol is represented by a cyclic shifted chirp over the bandwidth centered around the base frequency. The spreading factor (SF) is a selectable radio parameter from 5 to 12^[14] and represents the number of bits sent per symbol and in addition determines how much the information is spread over time.^[15] There are M = 2 S F {\displaystyle M=2^{\mathrm {SF} }} different initial frequencies of the cyclic shifted chirp across the bandwidth around the center frequency.^[16] The symbol rate is determined by R s = B / M {\displaystyle R_s=B/M}. LoRa can tradeoff data rate for sensitivity (assuming a fixed channel bandwidth B {\displaystyle B}) by selecting the SF, i.e. the amount of spread used. A lower SF corresponds to a higher data rate but a worse sensitivity, a higher SF implies a better sensitivity but a lower data rate.^[17] Compared to lower SF, sending the same amount of data with higher SF needs more transmission time, known as time-on-air. More time-on-air means that the modem is transmitting for a longer time and consuming more energy. Typical LoRa modems support transmit powers up to +22 dBm.^[14] However, the regulations of the respective country may additionally limit the allowed transmit power. Higher transmit power results in higher signal power at the receiver and hence a higher link budget, but at the cost of consuming more energy. There are measurement studies of LoRa performance with regard to energy consumption, communication distances, and medium access efficiency.^[18] According to the LoRa Development Portal, the range provided by LoRa can be up to 3 miles (4.8 km) in urban areas, and up to 10 miles (16 km) or more in rural areas (line of sight).^[19]

In addition, LoRa uses forward error correction coding to improve resilience against interference. LoRa's high range is characterized by high wireless link budgets of around 155 dB to 170 dB.^[20] Range extenders for LoRa are called LoRaX.

While LoRa defines the lower physical layer, LoRaWAN is the MAC layer protocol and system architecture for the network. LoRaWAN defines the communication protocol for managing communication between low-power end-node devices and gateways.

The LoRaWAN network architecture consists of three main components:

• End Devices: These are the small, battery-powered sensors or trackers that are spread out in the field. Each device has a LoRa chip that allows it to transmit small packets of data over long distances using the LoRa radio protocol.
• Gateways (Base Stations): A gateway is a receiving station that is connected to the internet. It listens for LoRa signals from all the end devices within its range. When a gateway receives a data packet from a device, it forwards it to the central network server without processing it.^[21] A key feature of LoRaWAN is that a single data packet from a device can be picked up by multiple gateways simultaneously, which increases the network's reliability.
• Network Server: This is the central cloud-based software that manages the entire network. It receives the data from all the gateways, removes duplicate messages, and then routes the data to the correct application server. It is also responsible for managing the communication frequencies, data rate, and power for all end devices.^[22][23]

Devices in the network are asynchronous and transmit when they have data available to send. Data transmitted by an end-node device is received by multiple gateways, which then forward the data packets to the centralized network server.^[24] The data is then forwarded to an associated application server.^[25]

In the wireless communication, particularly across the IoT applications, collision avoidance is essential for reliable communication and overall spectral efficiency. Previously, LoRaWAN has relied upon ALOHA as the medium access control (MAC) layer protocol, but to improve this, the LoRa Alliance's Technical Recommendation TR013^[26] introduced CSMA-CA. Employing the CAD based CSMA technique specified in TR013^[26] enhances LoRaWAN's spectrum efficiency and ensures more reliable device communication, including in congested environments.^[26] TR013 is based on the LMAC^[27] and is the first industry-academia collaboration of LoRa Alliance to have resulted in a Technical Recommendation.^[28][29]

• January 2015: 1.0^[30][31]
• February 2016: 1.0.1^[32]
• July 2016: 1.0.2^[33]
• October 2017: 1.1, adds Class B^[34]
• July 2018: 1.0.3^[35]
• October 2020: 1.0.4^[36]

The LoRa Alliance is an open, non-profit association whose stated mission is to support and promote the global adoption of the LoRaWAN standard for massively scaled IoT deployments, as well as deployments in remote or hard-to-reach locations.

Members collaborate in a vibrant ecosystem of device makers, solution providers, system integrators and network operators, delivering interoperability needed to scale IoT across the globe, using public, private, hybrid, and community networks. Key areas of focus within the Alliance are smart agriculture, smart buildings, smart cities, smart industry, smart logistics, and smart utilities.

Key contributing members of the LoRa Alliance include Actility, Amazon Web Services, Cisco, Everynet, Helium, Kerlink, MachineQ, Microsoft, MikroTik, Minol Zenner, Netze BW, Semtech, Senet, STMicroelectronics, TEKTELIC and The Things Industries.^[37] In 2018, the LoRa Alliance had over 100 LoRaWAN network operators in over 100 countries; in 2023, there are nearly 200, providing coverage in nearly every country in the world.^[38]

On October 1, 2024, Cisco announced it is "exiting the LoRaWAN space" with no planned migration for Cisco LoRaWAN gateways.^[39]

• DASH7 – a popular open alternative to LoRa
• IEEE 802.11ah – non-proprietary low-power long-range standard
• CC430 – an MCU & sub-1 GHz RF transceiver SoC
• Narrowband IoT – narrowband Internet of things
• LTE Cat M1 – Cellular device technology
• MIoTy – sub-GHz LPWAN technology for sensor networks
• SCHC – static context header compression
• Short-range device – Class of radio transmitter
• Helium Network – LoRaWAN protocol paired with blockchain technology
• Amazon Sidewalk – a mesh wireless network developed by Amazon
• Meshtastic – a popular open source mesh network protocol that uses LoRa
• ExpressLRS – open source UAV remote control protocol that uses LoRa, widely used in FPV drones

• Olivier Bernard André Seller. "Wireless communication method" U.S. Patent No. 9,647,718. 9 September 2015.
• Lee, Chang-Jae, Ki-Seon Ryu, and Beum-Joon Kim. "Periodic ranging in a wireless access system for mobile station in sleep mode." U.S. Patent No. 7,194,288. 20 March 2007.
• Ghoslya, Sakshama (2019-04-17). "How to generate LoRa Symbols". All About LoRa and LoRaWAN.
• Quigley, Thomas J., and Ted Rabenko. "Latency reduction in a communications system." U.S. Patent No. 7,930,000. 19 April 2011.
• Bankov, D.; Khorov, E.; Lyakhov, A. "On the Limits of LoRaWAN Channel Access". 2016 International Conference on Engineering and Telecommunication (EnT): 10–14.
• Seneviratne, Pradeeka. "Beginning LoRa Radio Networks with Arduino - Build Long Range, Low Power Wireless IoT Networks." Apress, 2019, eBook ISBN 978-1-4842-4357-2, Softcover ISBN 978-1-4842-4356-5, Ed: 1

• LoRa Alliance
• LoRa Developer Portal
• Cycleo website at the Wayback Machine (archived 2011-07-29)