LoRa

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
LoRa
LoRa Module with antenna and SPI wires attached.jpg
A LoRa module
Developed bySemtech
Connector typeSPI/I2C
Compatible hardwareSX1261, SX1262, SX1268, SX1272, SX1276, SX1278
Physical range>10 km in perfect conditions

LoRa (from "long range") is a proprietary low-power wide-area network modulation technique.[1] It is based on spread-spectrum modulation techniques derived from chirp spread spectrum (CSS) technology.[2] It was developed by Cycleo of Grenoble, France and acquired by Semtech, the founding member of the LoRa Alliance; it is patented.[3]

Features[edit]

LoRa uses license-free sub-gigahertz radio frequency bands like EU433 (433.05-434.79 MHz) and EU863-870 (863–870/873 MHz) in Europe; AU915-928/AS923-1 (915–928 MHz) in Australia; US902-928 (902–928 MHz) in North America; IN865-867 (865–867 MHz) in India; AU915-928/AS923-1 and EU433 Southeast Asia;[4] and 2.4GHz worldwide.[5] LoRa enables long-range transmissions with low power consumption.[6] 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.[7]

LoRa devices have geolocation capabilities used for trilaterating positions of devices via timestamps from gateways.[8]

LoRa PHY[edit]

LoRa uses a proprietary spread spectrum modulation that is similar to and a derivative of chirp spread spectrum (CSS) modulation. The spread spectrum LoRa modulation is performed by representing each bit of payload information by multiple chirps of information. The rate at which the spread information is sent is referred to as the symbol rate, the ratio between the nominal symbol rate and chirp rate is the spreading factor (SF) and represents the number of symbols sent per bit of information.[2] The result is an M-ary digital modulation, where the possible waveforms at the output of the modulator are chirp modulated signals over the frequency interval () with M different initial frequencies: the instantaneous frequency is linearly increased, and then wrapped to when it reaches the maximum frequency .[9]

LoRa can trade off data rate for sensitivity with a fixed channel bandwidth by selecting the amount of spread used (a selectable radio parameter from 6 to 12 [10]). Lower SF means more chirps are sent per second; hence, you can encode more data per second. Higher SF implies fewer chirps per second; hence, there are fewer data to encode per second. Compared to lower SF, sending the same amount of data with higher SF needs more transmission time, known as airtime. More airtime means that the modem is up and running longer and consuming more energy. The benefit of high SF is that more extended airtime gives the receiver more opportunities to sample the signal power, which results in better sensitivity.[11] The LoRa modem allows changing of the transmission power from 2dBm to 14dBm (433 MHz) or as high as 20dBm (865 MHz to 867 MHz, 915 MHz, and 923 MHz) as per the regulations of each country. Higher transmission power gives the receiver better signal power and better sensitivity, 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.[12] According to the LoRa Development Portal, the range provided by LoRa can be up to three miles (five kilometers) in urban areas, and up to 10 miles (15 kilometers) or more in rural areas (line of sight).[13]

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.[14]

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.[15] 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.[16] Data are then forwarded to application servers.[17] The technology shows high reliability for the moderate load, however, it has some performance issues related to sending acknowledgements.[18]

Version history[edit]

  • January 2015: 1.0[19][20]
  • February 2016: 1.0.1[21]
  • July 2016: 1.0.2[22]
  • October 2017: 1.1, adds Class B[23]
  • July 2018: 1.0.3[24]
  • October 2020: 1.0.4[25]

LoRa Alliance[edit]

The LoRa Alliance is a 501(c)(6)[26] 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.[27] 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.[28] In 2018, the LoRa Alliance had over 100 LoRaWAN network operators in over 100 countries.[29] The Alliance is administered by the VTM Group in Beaverton, Oregon.[30]

LoRaWAN for 4G/5G networks[edit]

Researchers have proposed that LoRaWAN could solve some of the issues concerning power usage in 4G/5G technologies.

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
  • LTE Cat M1
  • MIoTy – sub-GHz LPWAN technology for sensor networks
  • SCHC – static context header compression

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. ^ "RP002-1.0.3 LoRaWAN Regional Parameters" (PDF). lora-alliance.org. Retrieved 9 June 2021.
  5. ^ "LoRa 2.4GHz". Semtech LoRa 2.4GHz. Archived from the original on 8 November 2021. Retrieved 8 November 2021.
  6. ^ 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.
  7. ^ 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.
  8. ^ Fargas, Bernat Carbones; Petersen, Martin Nordal. "GPS-free Geolocation using LoRa in Low-Power WANs" (PDF). DTU Library.
  9. ^ 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.
  10. ^ "SX1276-7-8-9 Datasheet". Semtech SX1276. Semtech. Retrieved 19 November 2021.
  11. ^ Qoitech. "How Spreading Factor affects LoRaWAN device battery life". The Things Network. Retrieved 2020-02-25.
  12. ^ 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 Network. 15 (2): Article No. 16, pp 1–35. doi:10.1145/3293534. ISSN 1550-4859. S2CID 53669421.
  13. ^ "What are LoRa® and LoRaWAN®?". LoRa Developer Portal. Retrieved 7 July 2021.
  14. ^ Mohan, Vivek. "10 Things About LoRaWAN & NB-IoT". blog.semtech.com. Retrieved 2019-02-18.
  15. ^ "LoRaWAN For Developers". www.lora-alliance.org. Retrieved 2018-11-23.
  16. ^ "A Comprehensive Look At LPWAN For IoT Engineers & Decision Makers". www.link-labs.com. Retrieved 2017-06-22.
  17. ^ LoRa Alliance (2015). "LoRaWAN: What is it?" (PDF).
  18. ^ 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.
  19. ^ "LoRaWAN Specification" (PDF). lora-alliance.org. Retrieved 5 February 2020.
  20. ^ Version 1.0 of the LoRaWAN specification released.
  21. ^ "LoRaWAN Specification". lora-alliance.org. Retrieved 2 February 2021.
  22. ^ "LoRaWAN Specification" (PDF). lora-alliance.org. Retrieved 5 February 2020.
  23. ^ "LoRaWAN™ 1.1 Specification" (PDF). lora-alliance.org. Retrieved 5 February 2020.
  24. ^ "LoRaWAN 1.0.3 Specification" (PDF). lora-alliance.org. Retrieved 5 February 2020.
  25. ^ "LoRaWAN 1.0.4 Specification". lora-alliance.org. Retrieved 25 November 2020.
  26. ^ 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 requires |journal= (help)
  27. ^ "Semtech's LoRa Alliance grows to 500 members". Pacific Coast Business Times. 2017-06-29. Retrieved 2019-02-09.
  28. ^ "Member Directory | LoRa Alliance". lora-alliance.org. Retrieved 2019-02-09.
  29. ^ "LoRa Alliance passes 100 LoRaWAN network operator milestone". Electronic Products & Technology. 2019-01-25. Retrieved 2019-02-11.
  30. ^ 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]