LoRa

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LoRa
LoRa Module with antenna and SPI wires attached.jpg
A LoRa module
Developed byCycleo, Semtech
Connector typeSPI/I2C
Compatible hardwareSX1261, SX1262, SX1268, SX1272, SX1276, SX1278
Physical range>10 kilometres (6.2 mi) in perfect conditions

LoRa (from "long range") is a physical proprietary radio communication technique.[1] It is based on spread spectrum modulation techniques derived from chirp spread spectrum (CSS) technology.[2] It was developed by Cycleo (patent 9647718-B2), a company of Grenoble, France, later acquired by Semtech.[3][4]

LoRaWAN defines the software communication protocol and system architecture. 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 (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 bi-directional communication, end-to-end security, mobility and localization services. The 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 kbit/s to 50 kbit/s per channel.[5]

Features[edit]

LoRa uses license-free sub-gigahertz radio frequency bands 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] and 2.4 GHz worldwide.[7] LoRa enables long-range transmissions with low power consumption.[8] The technology covers the physical layer, while other technologies and protocols such as LoRaWAN (Long Range Wide Area Network) cover the upper layers. It can achieve data rates between 0.3 kbit/s and 27 kbit/s, depending upon the spreading factor.[9]

LoRa devices have geolocation capabilities used for trilaterating positions of devices via timestamps from gateways.[10]

LoRa PHY[edit]

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 frequency interval () where is the center frequency and the bandwidth of the signal (in Hertz). The spreading factor (SF) is a selectable radio parameter from 5 to 12 [11] and represents the number of bits sent per symbol and in addition determines how much the information is spread over time.[2] There are different initial frequencies of the cyclic shifted chirp (the instantaneous frequency is linearly increased and wrapped to when it reaches the maximum frequency ).[12] The symbol rate is determined by . LoRa can trade off data rate for sensitivity (assuming a fixed channel bandwidth ) 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.[13] 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.[11] 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.[14] 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).[15]

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.[16] Range extenders for LoRa are called LoRaX.

LoRaWAN[edit]

Since LoRa defines the lower physical layer, the upper networking layers were lacking. LoRaWAN is one of several protocols that were developed to define the upper layers of the network. LoRaWAN is a cloud-based medium access control (MAC) layer protocol, but acts mainly as a network layer protocol for managing communication between LPWAN gateways and end-node devices as a routing protocol, maintained by the LoRa Alliance.

LoRaWAN defines the communication protocol and system architecture for the network, while the LoRa physical layer enables the long-range communication link. LoRaWAN is also responsible for managing the communication frequencies, data rate, and power for all devices.[17] Devices in the network are asynchronous and transmit when they have data available to send. Data transmitted by an end-node device are received by multiple gateways, which forward the data packets to a centralized network server.[18] Data are then forwarded to application servers.[19] The technology shows high reliability for the moderate load, however, it has some performance issues related to sending acknowledgements.[20]

Version history[edit]

  • January 2015: 1.0[21][22]
  • February 2016: 1.0.1[23]
  • July 2016: 1.0.2[24]
  • October 2017: 1.1, adds Class B[25]
  • July 2018: 1.0.3[26]
  • October 2020: 1.0.4[27]

LoRa Alliance [edit]

The LoRa Alliance is a 501(c)(6)[28] association created in 2015 to support LoRaWAN (long range wide-area network) protocol, as well as to ensure interoperability of all LoRaWAN products and technologies. This open, nonprofit association has over 500 members.[29] Some members of the LoRa Alliance are IBM, Everynet, Actility, MicroChip, Orange, Cisco, KPN, Swisscom, Semtech, A2A Smart City SPA, Bouygues Telecom, Singtel, Proximus, The Things Industries and Cavagna Group.[30] In 2018, the LoRa Alliance had over 100 LoRaWAN network operators in over 100 countries.[31] The Alliance is administered by the VTM Group in Beaverton, Oregon.[32]

LoRaWAN for 4G/5G networks[edit]

Researchers[who?] have proposed that LoRaWAN could solve some of the issues concerning power usage in 4G/5G technologies.[citation needed]

See also[edit]

  • 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
  • NB-IoT - Narrowband Internet of Things
  • LTE Cat M1
  • MIoTy – sub-GHz LPWAN technology for sensor networks
  • SCHC – static context header compression
  • Helium (cryptocurrency) - LoRaWAN protocol paired with blockchain technology

References[edit]

  1. ^ "What is LoRa?". Semtech. Retrieved 2021-01-21.
  2. ^ a b "LoRa Modulation Basics" (PDF). Semtech. Archived from the original (PDF) on 2019-07-18. Retrieved 2020-02-05.
  3. ^ "Semtech Acquires Wireless Long Range IP Provider Cycleo". Design And Reuse. Retrieved 2019-10-17.
  4. ^ US 9647718, "Wireless communication method", issued 2017-05-09 
  5. ^ Ferran Adelantado, Xavier Vilajosana, Pere Tuset-Peiro, Borja Martinez, Joan Melià-Seguí and Thomas Watteyne. Understanding the Limits of LoRaWAN (January 2017).
  6. ^ "RP002-1.0.3 LoRaWAN Regional Parameters" (PDF). lora-alliance.org. Retrieved 9 June 2021.
  7. ^ "LoRa 2.4GHz". Semtech LoRa 2.4GHz. Archived from the original on 8 November 2021. Retrieved 8 November 2021.
  8. ^ Ramon Sanchez-Iborra; Jesus Sanchez-Gomez; Juan Ballesta-Viñas; Maria-Dolores Cano; Antonio F. Skarmeta (2018). "Performance Evaluation of LoRa Considering Scenario Conditions". Sensors. 18 (3): 772. Bibcode:2018Senso..18..772S. doi:10.3390/s18030772. PMC 5876541. PMID 29510524.
  9. ^ Adelantado, Ferran; Vilajosana, Xavier; Tuset-Peiro, Pere; Martinez, Borja; Melia-Segui, Joan; Watteyne, Thomas (2017). "Understanding the Limits of LoRaWAN". IEEE Communications Magazine. 55 (9): 34–40. doi:10.1109/mcom.2017.1600613. hdl:10609/93072. ISSN 0163-6804. S2CID 2798291.
  10. ^ Fargas, Bernat Carbones; Petersen, Martin Nordal. "GPS-free Geolocation using LoRa in Low-Power WANs" (PDF). DTU Library.
  11. ^ a b "SX1261/2 Datasheet". Semtech SX1276. Semtech. Retrieved 19 November 2021.
  12. ^ M. Chiani; A. Elzanaty (2019). "On the LoRa Modulation for IoT: Waveform Properties and Spectral Analysis". IEEE Internet of Things Journal. 6 (5): 772. arXiv:1906.04256. doi:10.1109/JIOT.2019.2919151. hdl:10754/655888. S2CID 184486907.
  13. ^ Qoitech. "How Spreading Factor affects LoRaWAN device battery life". The Things Network. Retrieved 2020-02-25.
  14. ^ J.C. Liando; A. Gamage; A.W. Tengourtius; M. Li (2019). "Known and Unknown Facts of LoRa: Experiences from a Large-Scale Measurement Study". ACM Transactions on Sensor Networks. 15 (2): Article No. 16, pp 1–35. doi:10.1145/3293534. ISSN 1550-4859. S2CID 53669421.
  15. ^ "What are LoRa® and LoRaWAN®?". LoRa Developer Portal. Retrieved 7 July 2021.{{cite web}}: CS1 maint: url-status (link)
  16. ^ Mohan, Vivek. "10 Things About LoRaWAN & NB-IoT". blog.semtech.com. Retrieved 2019-02-18.
  17. ^ "LoRaWAN For Developers". www.lora-alliance.org. Retrieved 2018-11-23.
  18. ^ "A Comprehensive Look At LPWAN For IoT Engineers & Decision Makers". www.link-labs.com. Retrieved 2017-06-22.
  19. ^ LoRa Alliance (2015). "LoRaWAN: What is it?" (PDF).
  20. ^ Bankov, D.; Khorov, E.; Lyakhov, A. (November 2016). "On the Limits of LoRaWAN Channel Access". 2016 International Conference on Engineering and Telecommunication (EnT): 10–14. doi:10.1109/ent.2016.011. ISBN 978-1-5090-4553-2. S2CID 44799707.
  21. ^ "LoRaWAN Specification" (PDF). lora-alliance.org. Retrieved 5 February 2020.
  22. ^ Version 1.0 of the LoRaWAN specification released.
  23. ^ "LoRaWAN Specification". lora-alliance.org. Retrieved 2 February 2021.
  24. ^ "LoRaWAN Specification" (PDF). lora-alliance.org. Retrieved 5 February 2020.
  25. ^ "LoRaWAN™ 1.1 Specification" (PDF). lora-alliance.org. Retrieved 5 February 2020.
  26. ^ "LoRaWAN 1.0.3 Specification" (PDF). lora-alliance.org. Retrieved 5 February 2020.
  27. ^ "LoRaWAN 1.0.4 Specification". lora-alliance.org. Retrieved 25 November 2020.
  28. ^ Brad Biddle (7 May 2019). "Linux Foundation is Eating the World". SSRN 3377799. Many other organizations formed following this same basic template: incorporation as a mutual benefit non-profit corporation under applicable U.S. state law (with some slight variations of corporate form based on particular state law requirements), and then operation as a tax exempt entity under a provision targeted at “business leagues” and other trade association-style enterprises. This provision, Section 501(c)(6) of Title 26 of the U.S. Code, generally enabled the organizations to avoid paying federal income tax, and often to avoid most state and local taxes as well. Selecting from hundreds of examples, some organizations that follow this model include ... LoRa Alliance {{cite journal}}: Cite journal requires |journal= (help)
  29. ^ "Semtech's LoRa Alliance grows to 500 members". Pacific Coast Business Times. 2017-06-29. Retrieved 2019-02-09.
  30. ^ "Member Directory | LoRa Alliance". lora-alliance.org. Retrieved 2019-02-09.
  31. ^ "LoRa Alliance passes 100 LoRaWAN network operator milestone". Electronic Products & Technology. 2019-01-25. Retrieved 2019-02-11.
  32. ^ Gallivan, Joseph (5 January 2018). "Las Vegas Arrivals". Business Tribune. Retrieved 5 February 2020. The alliance is managed by the VTM Group in Beaverton ... Geoff Mulligan is the Chairman of the LoRa Alliance. He was a presidential innovation Fellow at the National Institute of Standards and Technology (NIST) under the Obama administration.

Further reading[edit]

External links[edit]