View source for LoRa

{{short description|Wireless communication technology}}
{{for|the deep learning fine-tuning technique|Fine-tuning (deep learning)#Low-rank_adaptation}}
{{Infobox protocol
| image       = LoRa_Module_with_antenna_and_SPI_wires_attached.jpg
| caption     = A LoRa module
| standard    = <!--[[IEEE 802.15.4]] not sure-->
| developer   = [[Cycleo]], [[Semtech]]
| introdate   = <!--{{Start date|2003|5}}-->
| industry    = <!--Industrial, scientific-->
| connector   = SPI/I2C
| hardware    = SX1261, SX1262, SX1268, SX1272, SX1276, SX1278 
| range       = {{convert|330|km|mi}} in perfect conditions.  <ref>{{Cite web |title=Range Tests {{!}} Meshtastic |url=https://meshtastic.org/docs/overview/range-tests/ |access-date=2025-01-22 |website=meshtastic.org |language=en}}</ref>

Approximately 10 kilometres (6.2 mi) in practical conditions
}}
'''LoRa''' (from "'''Lo'''ng '''Ra'''nge", sometimes abbreviated as "LR") is a physical proprietary [[radio communication]] technique.<ref>{{Cite web |title=What is LoRa? |url=https://www.semtech.com/lora/what-is-lora |access-date=2021-01-21 |website=Semtech |language=en}}</ref> It is based on [[spread spectrum]] modulation techniques derived from [[chirp spread spectrum]] (CSS) technology.<ref name="modbas">{{Cite web |url=https://www.semtech.com/uploads/documents/an1200.22.pdf |title=LoRa Modulation Basics |date= |website=[[Semtech]] |url-status=dead |archive-url=https://web.archive.org/web/20190718200516/https://www.semtech.com/uploads/documents/an1200.22.pdf |archive-date=2019-07-18 |access-date=2020-02-05}}</ref> It was developed by Cycleo, a company of [[Grenoble|Grenoble, France]], and patented in 2014.<ref>{{cite patent |country=US |number=9647718 |title=Wireless communication method |fdate=2015-09-09 |gdate=2017-05-09}}</ref> In March 2012, Cycleo was acquired by the US company [[Semtech]].<ref>{{Cite web |url=https://www.design-reuse.com/news/28706/semtech-cycleo-acquisition.html |title=Semtech Acquires Wireless Long Range IP Provider Cycleo |website=Design And Reuse |language=en |access-date=2019-10-17}}</ref>

'''LoRaWAN''' (Long Range [[Wide Area Network]]) defines the communication protocol and system architecture. LoRaWAN is an official standard of the [[International Telecommunication Union]] (ITU), ITU-T Y.4480.<ref>{{Cite web |url=https://www.eenewswireless.com/en/lorawan-recognized-as-itu-international-lpwan-standard/ |title=LoRaWAN® recognized as ITU International LPWAN standard |website=eenewswireless |date=8 December 2021 |language=en |access-date=2021-12-31}}</ref> The continued development of the LoRaWAN protocol is managed by the open, non-profit LoRa Alliance, of which Semtech is a founding member.

Together, LoRa and LoRaWAN define a [[low-power wide-area network|low-power, wide-area]] (LPWA) networking protocol designed to wirelessly connect battery operated devices to the Internet in regional, national or global networks, and targets key [[Internet of things]] (IoT) requirements, such as [[Duplex (telecommunications)|bi-directional communication]], end-to-end security, mobility and localization services. The [[Low-power electronics|low power]], low bit rate, and IoT use distinguish this type of network from a [[wireless WAN]] that is designed to connect users or businesses, and carry more data, using more power. The LoRaWAN data rate ranges from 0.3&nbsp;kbit/s to 50&nbsp;kbit/s per
channel.<ref>[https://arxiv.org/abs/1607.08011 Ferran Adelantado, Xavier Vilajosana, Pere Tuset-Peiro, Borja Martinez, Joan Melià-Seguí and Thomas Watteyne. Understanding the Limits of LoRaWAN (January 2017).]</ref>
{{Internet of Things}}

== Features ==
LoRa uses license-free sub-gigahertz [[radio frequency]] bands EU868 ([[Short-range device#SRD860|863–870/873&nbsp;MHz]]) in [[Europe]]; AU915/AS923-1 (915–928&nbsp;MHz) in [[South America]]; US915 ([[ISM radio band#915 MHz|902–928&nbsp;MHz]]) in [[North America]]; IN865 (865–867&nbsp;MHz) in [[India]]; and AS923 (915–928&nbsp;MHz) in [[Asia]];<ref name="loraWANRegionalParameters">{{Cite web |title=RP002-1.0.3 LoRaWAN Regional Parameters |author= |work=lora-alliance.org |date= |access-date=9 June 2021 |url= https://lora-alliance.org/wp-content/uploads/2021/05/RP-2-1.0.3.pdf}}</ref> LoRa enables long-range transmissions with low power consumption.<ref name="sanchez">{{cite journal|author1=Ramon Sanchez-Iborra |author2=Jesus Sanchez-Gomez |author3=Juan Ballesta-Viñas |author4=Maria-Dolores Cano |author5=Antonio F. Skarmeta |title=Performance Evaluation of LoRa Considering Scenario Conditions |journal=Sensors |volume=18 |issue=3 |pages=772 |year=2018 |doi=10.3390/s18030772 |pmid=29510524 |pmc=5876541 |bibcode=2018Senso..18..772S |doi-access=free }}</ref> 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&nbsp;kbit/s and 27&nbsp;kbit/s, depending upon the spreading factor.<ref>{{Cite journal|last1=Adelantado|first1=Ferran|last2=Vilajosana|first2=Xavier|last3=Tuset-Peiro|first3=Pere|last4=Martinez|first4=Borja|last5=Melia-Segui|first5=Joan|last6=Watteyne|first6=Thomas|date=2017|title=Understanding the Limits of LoRaWAN|journal=IEEE Communications Magazine|volume=55|issue=9|pages=34–40|doi=10.1109/mcom.2017.1600613|hdl=10609/93072|s2cid=2798291|issn=0163-6804|hdl-access=free}}</ref>

LoRa is one of the most popular low-power [[wireless sensor network]] technologies for the implementation of the Internet of Things, offering long-range communication compared to technologies such as Zigbee or Bluetooth, but with lower data rates.<ref name="coutinho">{{cite journal|author1=Micael Coutinho |author2=Jose A. Afonso |author3=Sergio F. Lopes |title= An Efficient Adaptive Data-Link-Layer Architecture for LoRa Networks |journal=Future Internet |volume=15 |issue=8 |pages=273 |year=2023 |doi= 10.3390/fi15080273 |doi-access=free |hdl=1822/87237 |hdl-access=free }}</ref>

LoRa devices have [[geolocation]] capabilities used for [[Trilateration|trilaterating]] positions of devices via timestamps from gateways.<ref>{{Cite web|url=http://orbit.dtu.dk/files/130478296/paper_final_2.pdf|title=GPS-free Geolocation using LoRa in Low-Power WANs|author1=Fargas, Bernat Carbones |author2=Petersen, Martin Nordal |date=|website=DTU Library|archive-url=|archive-date=|access-date=}}</ref>

==LoRa PHY==
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<ref name=":1">{{cite web |title=SX1261/2 Datasheet |url=https://www.semtech.com/products/wireless-rf/lora-core/sx1262#download-resources |access-date=19 November 2021 |website=Semtech SX1276 |publisher=Semtech}}</ref> and represents the number of bits sent per symbol and in addition determines how much the information is spread over time.<ref name="modbas" /> There are <math>M = 2^{\mathrm{SF}}</math> different initial frequencies of the cyclic shifted chirp across the bandwidth around the center frequency.<ref name="chel">{{cite journal|author1=M. Chiani |author2=A. Elzanaty |title=On the LoRa Modulation for IoT: Waveform Properties and Spectral Analysis |journal=IEEE Internet of Things Journal |volume=6 |issue=5 |pages=772 |year=2019 |doi= 10.1109/JIOT.2019.2919151|arxiv=1906.04256 |hdl=10754/655888 |s2cid=184486907 |hdl-access=free }}</ref> The symbol rate is determined by <math>R_s = B/M</math>. LoRa can trade off data rate for sensitivity (assuming a fixed channel bandwidth <math>B</math>) 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.<ref>{{Cite web |last=Qoitech |title=How Spreading Factor affects LoRaWAN device battery life |url=https://www.thethingsnetwork.org/article/how-spreading-factor-affects-lorawan-device-battery-life |access-date=2020-02-25 |website=The Things Network |language=en}}</ref> 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&nbsp;dBm.<ref name=":1" /> 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.<ref name="measurement_studies">{{cite journal|author1=J.C. Liando |author2=A. Gamage |author3=A.W. Tengourtius |author4=M. Li |title=Known and Unknown Facts of LoRa: Experiences from a Large-Scale Measurement Study |journal=ACM Transactions on Sensor Networks |volume=15 |issue=2 |pages=Article No. 16, pp 1–35 |year=2019 |doi= 10.1145/3293534 |s2cid=53669421 |issn=1550-4859 |hdl=10356/142869 |hdl-access=free }}</ref> According to the LoRa Development Portal, the range provided by LoRa can be up to {{convert|3|mi|km}} in urban areas, and up to {{convert|10|mi|km}} or more in rural areas (line of sight).<ref>{{Cite web|title=What are LoRa® and LoRaWAN®?|url=https://lora-developers.semtech.com/library/tech-papers-and-guides/lora-and-lorawan/|access-date=7 July 2021|website=LoRa Developer Portal}}</ref>

In addition, LoRa uses [[Forward error correction|forward error correction coding]] to improve resilience against interference. LoRa's high range is characterized by high wireless [[link budget]]s of around 155&nbsp;dB to 170&nbsp;dB.<ref>{{Cite web|url=https://blog.semtech.com/title-10-things-about-lorawan-nb-iot|title=10 Things About LoRaWAN & NB-IoT|last=Mohan|first=Vivek|website=blog.semtech.com|language=en-us|access-date=2019-02-18}}</ref> Range extenders for LoRa are called LoRaX.

==LoRaWAN==
[[File:LoRaWAN-Architecture.svg|thumb|LoRaWAN network architecture]]
Since LoRa defines the lower, physical, layer, the upper networking layers were lacking. The specification consist of two parts. The actual LoRaWAN acts as a cloud controlled  [[Medium access control|MAC]] layer protocol for managing communication between [[LPWAN]] [[Gateway (telecommunications)|gateways]] and end-node devices. For communication within the cloud, LoRaWAN specifies data formats for higher layers, while the transport protocol could be any Internet protocol.

LoRaWAN defines the communication protocol and system architecture for the network, while LoRa's physical layer enables the long-range communication link. LoRaWAN is also responsible for managing the communication frequencies, [[Data-rate units|data rate]], and power for all devices.<ref>{{Cite web|url=https://lora-alliance.org/lorawan-for-developers|title=LoRaWAN For Developers|website=www.lora-alliance.org|language=en-US|access-date=2018-11-23}}</ref> 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. Each gateway has a multi-channel receiver, while the end-devices can hop between the channels using a single channel transceiver. Gateways forward the data packets without further processing to a centralized network server.<ref name=":0">{{Cite web|url=https://www.link-labs.com/lpwan|title=A Comprehensive Look At LPWAN For IoT Engineers & Decision Makers|date=|website=www.link-labs.com|archive-url=|archive-date=|access-date=2017-06-22}}</ref> This technology shows high reliability for the moderate load, however, it has some performance issues with sending acknowledgements (2016).<ref>{{Cite book |last1=Bankov |first1=D. |last2=Khorov |first2=E. |last3=Lyakhov |first3=A. |title=2016 International Conference on Engineering and Telecommunication (EnT) |chapter=On the Limits of LoRaWAN Channel Access |date=November 2016 |pages=10–14 |doi=10.1109/ent.2016.011|isbn=978-1-5090-4553-2 |s2cid=44799707 }}</ref>

The data is then further forwarded to an associated application server.<ref>{{Cite web |last=LoRa Alliance |date=2015 |title=LoRaWAN: What is it? |url=https://lora-alliance.org/sites/default/files/2018-04/what-is-lorawan.pdf |archive-url= |archive-date= |access-date= |website=}}</ref><ref>Example of LoRaWan IoT end device transmitting data. [https://www.cloud.studio/ Cloud Studio] platform used: https://gear.cloud.studio/gear/monitor/shared-dashboard/88c96030a42c4a1fa2669286a6bde321</ref> The cloud back-end interface definition uses JSON as data format. The cloud network specifies secure joining protocols for end-devices and possibilities for roaming between gateways. The application data payload is encrypted between the end-device and the cloud application and the content format is not specified by LoRaWAN.

=== CSMA for LoRaWAN ===
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 [[ALOHAnet|ALOHA]] as the [[medium access control]] (MAC) layer protocol, but to improve this, the LoRa Alliance's Technical Recommendation TR013<ref name=":2">{{Cite web |title=Enabling CSMA for LoRaWAN TR013-1.0.0 |url=https://resources.lora-alliance.org/home/tr013-1-0-0-csma |access-date=2023-11-05 |publisher=LoRa Alliance}}</ref> introduced [[Carrier-sense multiple access with collision avoidance|CSMA-CA]], which does not debilitate LoRa's distinctive modulation advantages such as Spreading Factor orthogonality,<ref name="measurement_studies" /> and the capability for below [[noise-floor]] communication.<ref name="measurement_studies" /> Employing the CAD based CSMA technique specified in TR013<ref name=":2" /> overcomes the limitations of relying on ''Received Signal Strength'' (RSS)-based sensing, which is unable to maintain the two said advantages of LoRa modulation. Therefore, implementing TR013 enhances LoRaWAN's spectrum efficiency and ensures more reliable device communication, including in congested environments.<ref name=":2" /> TR013 is based on the LMAC<ref>{{Cite journal |last1=Gamage |first1=Amalinda |last2=Liando |first2=Jansen |last3=Gu |first3=Chaojie |last4=Tan |first4=Rui |last5=Li |first5=Mo |last6=Seller |first6=Olivier |date=2023-05-31 |title=LMAC: Efficient Carrier-Sense Multiple Access for LoRa |url=https://dl.acm.org/doi/10.1145/3564530 |journal=ACM Transactions on Sensor Networks |language=en |volume=19 |issue=2 |pages=1–27 |doi=10.1145/3564530 |issn=1550-4859}}</ref> and is the first industry-academia collaboration of LoRa Alliance to have resulted in a Technical Recommendation.<ref>{{Cite thesis |title=Optimizing spectral utilization of LPWANs |publisher=Nanyang Technological University |date=2023 |doi=10.32657/10356/172897 |first=Gamage Isuru Amalinda |last=Jathun|doi-access=free |hdl=10356/172897 }}</ref><ref>{{Cite AV media |url=https://www.youtube.com/watch?v=4B8OY2jaLA4&t=681s |title=LoRaWAN® CSMA to Minimize on Air Collisions |date=2024-02-01 |last=LoRa Alliance |access-date=2024-07-13 |via=YouTube}}</ref>

=== Version history ===
* January 2015: 1.0<ref name="lora0">{{Cite web |title=LoRaWAN Specification |author= |work=lora-alliance.org |date= |access-date=5 February 2020 |url= https://lora-alliance.org/sites/default/files/2018-05/2015_-_lorawan_specification_1r0_611_1.pdf}}</ref><ref>[http://www.businesswire.com/news/home/20150616006550/en/LoRaWAN-R1.0-Open-Standard-Released-IoT Version 1.0 of the LoRaWAN specification released].</ref>
* February 2016: 1.0.1<ref name="lora1">{{Cite web |title=LoRaWAN Specification |author= |work=lora-alliance.org |date= |access-date=2 February 2021 |url= https://lora-alliance.org/resource_hub/lorawan-104-specification-package/}}</ref>
* July 2016: 1.0.2<ref name="lora2">{{Cite web |title=LoRaWAN Specification |author= |work=lora-alliance.org |date= |access-date=5 February 2020 |url= https://lora-alliance.org/sites/default/files/2018-05/lorawan1_0_2-20161012_1398_1.pdf}}</ref>
* October 2017: 1.1, adds Class B<ref name="lora11">{{Cite web |title=LoRaWAN™ 1.1 Specification |author= |work=lora-alliance.org |date= |access-date=5 February 2020 |url= https://lora-alliance.org/sites/default/files/2018-04/lorawantm_specification_-v1.1.pdf}}</ref>
* July 2018: 1.0.3<ref name="lora3">{{Cite web |title=LoRaWAN 1.0.3 Specification |author= |work=lora-alliance.org |date= |access-date=5 February 2020 |url= https://lora-alliance.org/sites/default/files/2018-07/lorawan1.0.3.pdf}}</ref>
* October 2020: 1.0.4<ref name="lora4">{{Cite web |title=LoRaWAN 1.0.4 Specification |author= |work=lora-alliance.org |date= |access-date=25 November 2020 |url= https://resources.lora-alliance.org/technical-specifications/ts001-1-0-4-lorawan-l2-1-0-4-specification}}</ref>

=== LoRa Alliance {{anchor|Alliance}} ===
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 Systems|Cisco]], Everynet, [[Helium Network|Helium]], Kerlink, MachineQ, a [[Comcast]] Company, [[Microsoft]], [[MikroTik]], Minol Zenner, Netze BW, Semtech, Senet, [[STMicroelectronics]], TEKTELIC and The Things Industries.<ref>{{Cite web |title=Member Directory {{!}} LoRa Alliance |url=https://lora-alliance.org/member-directory |access-date=May 22, 2023 |website=lora-alliance.org}}</ref> 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.<ref>{{Cite web |date=2019-01-25 |title=LoRa Alliance passes 100 LoRaWAN network operator milestone |url=https://lora-alliance.org/lora-alliance-press-release/lora-alliance-registra-una-crescita-del-66-delle-reti-pubbliche-lorawan-negli-ultimi-3-anni/ |access-date=2019-02-11 |website=Electronic Products & Technology |language=en-US}}</ref>

On October 1, 2024, [[Cisco Systems|Cisco]] announced it is "exiting the LoRaWAN space" with no planned migration for Cisco LoRaWAN gateways.<ref>{{Cite web |title=End-of-Sale and End-of-Life Announcement for the Cisco LoRaWAN |url=https://www.cisco.com/c/en/us/products/collateral/routers/wireless-gateway-lorawan/lorawan-eol.html |access-date=October 3, 2024 |website=cisco.com}}</ref>

==See also==

*[[DASH7]] — a popular open alternative to LoRa
*[[IEEE 802.11ah]] — non-proprietary low-power long-range standard
*[[CC430]] — an MCU & sub-1&nbsp;GHz RF transceiver SoC
*[[NB-IoT]] — Narrowband Internet of Things
* {{Annotated link |LTE-M|LTE Cat M1}}
*[[MIoTy]] — sub-GHz LPWAN technology for sensor networks
*[[Static Context Header Compression|SCHC]] — static context header compression
* {{Annotated link |Short-range device}}
*[[Helium (cryptocurrency)]] — 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

==References==
{{reflist}}

==Further reading==
* 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.
* {{Cite web|url=https://www.sghoslya.com/p/lora-is-chirp-spread-spectrum.html|title=How to generate LoRa Symbols|last=Ghoslya|first=Sakshama|date=2019-04-17|website=All About LoRa and LoRaWAN|archive-url=|archive-date=|access-date=}}
*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. [https://ieeexplore.ieee.org/document/7810745/ "On the Limits of LoRaWAN Channel Access"]. ''2016 International Conference on Engineering and Telecommunication (EnT)'': 10–14.
*Seneviratne, Pradeeka. [https://www.apress.com/us/book/9781484243565 "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

==External links==
* [https://lora-alliance.org/ LoRa Alliance]
* [https://lora-developers.semtech.com/library/tech-papers-and-guides/lora-and-lorawan/ LoRa Developer Portal]
* {{webarchive | url=https://web.archive.org/web/20110729143237/http://www.Cycleo.net/ | title=Cycleo website}}

[[Category:Wireless networking]]
[[Category:Wireless communication systems]]
[[Category:Wireless sensor network]]

[[de:Long Range Wide Area Network]]