• Signal spectrum auction and their prices. Source: The things Network
    image
  • LoRa Architecture Diagram Source: The Things Network
    image
  • LoRa has been shown to work at a range of 702km. Source: The Things Network
    image
  • Smart street lights with LoRa Source: intelilight.eu
    image
  • Layers of LoRa Source: Medium.com
    image
  • LoRa Signal in SDR Source: The Things Network
    image
  • Modulation of Chirp Spread Spectrum Source: Semtech
    image
  • LoRa Network Source: LoRa Alliance
    image
  • LoRa Modules
    image
  • Kibana Dashboard Source: elastic.io
    image
  • History of LPWAN Source: Link Labs
    image

LoRa

userimg
Vishwas
1111 DevCoins
userimg
arvindpdmn
299 DevCoins
2 authors have contributed to this article
Last updated by Vishwas
on 2018-06-19 02:52:34
Created by Vishwas
on 2018-06-15 18:57:12
Improve this article. Show messages

Summary

According to Cisco's Internet Business Solution Group, there will be around 50 billion connected devices in the world in the year 2020. For this to happen there must be some novel way to connect these devices to the internet with low power and long range. Here's how LoRa comes into the picture.

LoRa stands for Long Range. LoRa devices are low power, long range devices that can transmit and receive data over the unlicensed wireless frequency spectrum. This helps to get the critical sensor data from one place to another without any worries. This bidirectional communication is provided as both free and paid services.

Milestones

1899

Guglielmo Marconi experiments with frequency-selective reception in an attempt to reduce interference.

1942

Actress Hedy Lamarr and composer George Antheil are awarded U.S. Patent 2292387 for frequency hopping. Their patent application is titled "Secret Communications System". During World War II, US military uses frequency hopping methods. Years later, this technology becomes important for wireless communication technologies.

2008

First patent of LoRa is filed by French company Cycleo SAS. This uses a technology called Chirp Modulation. The U.S. Patent US7791415 is titled "Fractional-N Synthesized Chirp Generator".

Mar
2012

Semtech acquires Cycleo SAS for $5M. Semtech is a company involved in manufacturing of analog and mixed signal semiconductors for various industries.

Feb
2013

Second patent of LoRa is filed by Semtech. Patent EP2763321 titled "Low power Long range transmitter" describes the use of chirp modulation to transmit low-power signals over long distances.

2015

At Mobile World Congress, LoRa Alliance is launched in a formal way . Three companies are involved in its formation: Actility, Semtech and IBM Research. Currently, the Alliance has 57 members.

2015

MAC layer is defined by the LoRa Alliance. MAC layer is open and can be modified by anyone.

Mar
2018

Google announces that it will be joining LoRa Alliance as a sponsor member.

Jun
2018

LoRa drives IoT evolution at Mobile World Congress at Shanghai.

Discussion

  • Who invented LoRa?

    The technology was invented by a startup in France called Cycleo whose employees are veterans of big semiconductor companies who wanted to build a long range low power communication device. They filed a patent in 2008 titled "Fractional-N Synthesized Chirp Generator" and another in 2013 titled "Low power Long range transmitter". Later this company was acquired by another French company named Semtech that's into manufacturing of analogue and mixed-signal semiconductors.

  • What led to the wider deployment of LoRa?
    image
    Signal spectrum auction and their prices. Source: The things Network

    Cellular networks such as GPRS and 2G were used for machine-to-machine (M2M) data communication, particularly for sending data from remote locations. Such networks used relatively less power compared to 3G or LTE. But by the end of 2016 and beginning of 2017, network operators such as Telstra (Australia) and AT&T (US) announced the termination of 2G and GPRS. Communication protocols like these required the auction of spectrum costing millions of dollars. 3GPP's own NB-IoT standard launched only in early or mid-2018. This created a void in between. There was a need for a protocol that catered to low power, long range and bi-directional communication devices. This led to the wider deployment of LoRa network.

  • What are the advantages of LoRa?
    image
    LoRa Architecture Diagram Source: The Things Network

    LoRa has the following advantages:

    • Long Range: Many miles, on line-of-sight links.
    • Low power: Can run on battery for years.
    • Bi-directional: Can send and receive data. This means that uplink can be used for continuous monitoring of certain parameters and downlink can be used for controlling the devices.
    • Network security: Uses AES-128-bit end-to-end encryption.
    • Asset tracking without GPS: Uses Time of Flight (TOF) algorithm.
    • Low cost: LoRa modules are pocket-friendly.
    • Network scalability: Easy to scale as it supports millions of messages per station.
    • Easy commissioning: Easy to deploy in the existing system.
  • What is the range of LoRa?
    image
    LoRa has been shown to work at a range of 702km. Source: The Things Network

    LoRa a range of up to 13.5 miles in line of sight. This also depends on transmitting power of antenna, etc.

    In an experiment using a weather balloon, packet sent from it was received by a gateway 702km away. The balloon was at an altitude of 38.772 km. At this height, a single packet was sent from the node and it was received by 148 different gateways connected to The Things Network. One of the gateways reached was located in Wrocław, Poland. By that time, the balloon was flying over Osterwald in Germany, just across the German border from The Netherlands. A distance of 702.676km was reached, just by using 25mW (14dBm) of transmitting power, which is roughly 40 times smaller than what a mobile phone uses.

  • What are the technical details of LoRa?
    image
    Smart street lights with LoRa Source: intelilight.eu

    LoRa operates on a different range of frequencies in the different parts of the world. In the USA it operates at 902-928MHz. In Europe, it operates at 863-870MHz. In India, it operates at 3 channels: 865.0625 MHz, 865.4025 MHz, 865.9850 MHz

    It has sensitivity from -137dBm to +157dB of link budget. A LoRa devices consumes less power; that is, low receive current of 9.9 mA and 200 nA for register retention. Packets can be up to 256 bytes with CRC (cyclic redundancy check). Depending on the module, bit rate is programmable up to 300 kbps.

  • How is LoRa different from LoRaWAN?
    image
    Layers of LoRa Source: Medium.com

    LoRa is a proprietary modulation technique owned by Semtech. SX1272 and SX1276 are LoRa chips that use the modulation technique called Chirp Spread Spectrum (CSS) at the physical (PHY) layer of the stack.

    LoRaWAN is an open-standard that defines the communication protocol for LPWAN technology based on a LoRa chip. LoRaWAN defines the media access control (MAC) in the data link layer (DLL) and this maintained by the LoRa Alliance. This difference between LoRa and LoRaWAN is important because other companies such as Link Labs use a proprietary MAC layer on top of a LoRa chip to create a better performing custom hybrid design. In Link Labs case, it's called Symphony Link.

    LoRa remains proprietary and cannot be modified. Only the LoRaWAN can be modified.

  • Could you share some details about how LoRa works?
    image
    LoRa Signal in SDR Source: The Things Network

    Although LoRa is proprietary and cannot be modified, hobbyists have analyzed and documented it. Mathew Knight and Balint Seeber from Bastille Networks have used LoRa module and Software Defined Radio (SDR) to decode the LoRa signal. They detail the basic workings of LoRa:

    • The preamble of the signal contains variable numbers which is basically the number of chirps. If there is a constant number of chirps at the right frequency and at the right chirp rate, a LoRa demodulator will listen to it, whether it's from the intended system or not.
    • After locking the preamble, the end of the preamble is signalled by sending reverse chirp; that is, 2.25 down chirp.
    • Start Frame Delimiter (SFD) can be observed here. This contains up chirps of varying length. Instantaneous frequency changes are the result of data being modulated on to the chirps. These hobbyists de-chirped the signal with the help of a locally generated signal. Then Fast Fourier Transform (FFT) of this signal is taken. Length of FFT = Number of possible symbols. The most powerful component is the sent symbol.
  • What is chirp modulation?
    image
    Modulation of Chirp Spread Spectrum Source: Semtech

    By increasing the bandwidth of signal we can compensate for degradation of Signal-to-Noise Ratio (SNR). Since the chirp signal occurs faster than the data signal, it's thereby spreading the signal over a large bandwidth. At the receiver, the demodulation is done by multiplying the received signal by the locally generated signal.

    Chirp Spread Spectrum (CSS) was developed for radar applications in the 1940s. Over the past twenty years, this modulation has seen increased adoption in a number of data communications applications due to its relatively low transmission power requirements and inherent robustness from channel degradation mechanisms such as multipath, fading, Doppler and in-band jamming interferers.

  • Where LoRa has been deployed?
    image
    LoRa Network Source: LoRa Alliance

    LoRa is widely deployed over Europe, the US and Asian subcontinents. KPN network has deployed LoRa all over the Netherlands. MachineQ is the LoRaWAN provider in the USA. Alibaba Cloud deployed LoRaWAN in China. Tata Communications deployed LoRaWAN in India. The Things Network is providing LoRaWANs through its gateways across Europe.

    By early 2018, LoRa had 60+ public networks and 350+ ongoing trials in 100+ countries. LoRaWAN is a networking stack that uses LoRa. Symphony Link and Haystack's Dash7 are alternatives that uses LoRa.

  • Who supplies the chipsets?
    image
    LoRa Modules

    The first LoRa commercial chipsets were manufactured by Semtech. These are SX12XX series chips. Now there are many semiconductor companies such as Microchip and Murata who are manufacturing the chips compatible with their microcontrollers. Semtech leveraged the manufacturing of chipsets into a Taiwanese company Kiwi Technology to deploy LoRa across Taiwan.

  • What tools are useful for operating LoRa-based networks?
    image
    Kibana Dashboard Source: elastic.io

    There are many tools available online for the LoRa service. LoRatools provides many tools such as Key generator, Thingpark import helper, Hex helper and Airtime calculator. For data visualisation, open source visualisers such as Kibana can be used.

  • Could you name some alternatives to LoRa?
    image
    History of LPWAN Source: Link Labs

    LoRa has the following alternatives:

    • SigFox: It was deployed in France in September 2017. It's operating in 36 countries. It claims to work for 10 years on a single AA battery.
    • NB-IoT: This is a cellular-based network optimised for low power consumption and long-range communication. Compared to LoRa, NB-IoT has the advantages of an already mature ecosystem for mobile networks with support from telecom equipment vendors.
    • RPMA: Owned by the US company Ingenu, RPMA stands for Random Phase Multiple Access and useful for building machine networks.

References

  1. Application Note AN1200.22 by Semtech. 2015.
  2. Datasheet of Semtech SX1276. 2015.
  3. Decoding Physical Layer of LoRa. 2016.
  4. Fractional-N Synthesized Chirp Generator. 2008.
  5. Frequency Hopping Spread spectrum. 2018.
  6. LoRa Alliance. 2015.
  7. LoRaWAN Frequencies Overview. 2015.
  8. LoRaWAN by The Things Network.2015.
  9. Low power Long range transmitter. 2013.
  10. What is LoRa Technology?. 2015.

Milestones

1899

Guglielmo Marconi experiments with frequency-selective reception in an attempt to reduce interference.

1942

Actress Hedy Lamarr and composer George Antheil are awarded U.S. Patent 2292387 for frequency hopping. Their patent application is titled "Secret Communications System". During World War II, US military uses frequency hopping methods. Years later, this technology becomes important for wireless communication technologies.

2008

First patent of LoRa is filed by French company Cycleo SAS. This uses a technology called Chirp Modulation. The U.S. Patent US7791415 is titled "Fractional-N Synthesized Chirp Generator".

Mar
2012

Semtech acquires Cycleo SAS for $5M. Semtech is a company involved in manufacturing of analog and mixed signal semiconductors for various industries.

Feb
2013

Second patent of LoRa is filed by Semtech. Patent EP2763321 titled "Low power Long range transmitter" describes the use of chirp modulation to transmit low-power signals over long distances.

2015

At Mobile World Congress, LoRa Alliance is launched in a formal way . Three companies are involved in its formation: Actility, Semtech and IBM Research. Currently, the Alliance has 57 members.

2015

MAC layer is defined by the LoRa Alliance. MAC layer is open and can be modified by anyone.

Mar
2018

Google announces that it will be joining LoRa Alliance as a sponsor member.

Jun
2018

LoRa drives IoT evolution at Mobile World Congress at Shanghai.

Tags

See Also

Further Reading

  1. 11 Myths About LoRaWAN. 2016.
  2. National Connectivity Via LoRaWAN. 2017.
  3. Semtech’s LoRa Technology Is Leveraged by Kiwi Technology to Develop Smart Cities in Thailand. 2018.
  4. Semtech’s LoRa Technology Drives the IoT Evolution. 2018.
  5. LoRa Connectivity by KPN. 2017.
  6. Ground breaking world record! LoRaWAN packet received at 702 km (436 miles) distance. 2017.

Article Stats

Author-wise Stats for Article Edits

Author
No. of Edits
No. of Chats
DevCoins
6
0
1111
1
1
299
1638
Words
1
Chats
7
Edits
10
Likes
2467
Hits

Cite As

Devopedia. 2018. "LoRa." Version 7, June 19. Accessed 2019-06-27. https://devopedia.org/lora