LoRaWAN and Sigfox lead LPWANs; Interoperability via Compression

Backgrounder:

The Low Power Wide Area Network (LPWAN) market is focused on IoT WAN connectivity for devices (endpoints) that consume low power, send/receive short messages at low speeds, and have low duty cycles.   There are two categories of LPWANs:

1] Cellular (e.g. NB-IoT and LTE Category M1) WANs using licensed spectrum.

2] Wireless WANs operating in unlicensed frequency bands.

While cellular may be the ultimate winner, Sigfox and LoRAWAN currently have a lot more market traction and are growing very fast.  Other non-cellular LPWANs (Ingenu, Weightless SIG, etc.) are also getting some attention, but if there are too many commercially available LPWANs the market will be segmented and fractured.

Overview of LoRaWAN and Sigfox network:

Let’s look at the two most popular unlicensed band LPWANs:

1.  LoRaWAN:

  • LoRaWAN is specified by the LoRa Alliance which includes 47 network operators.

  • The LoRa Alliance states on its website: “LoRaWAN™ is the open global standard for secure, carrier-grade IoT LPWA connectivity. With a certification program to guarantee interoperability and the technical flexibility to address the multiple IoT applications be they static or mobile we believe that LoRaWAN can give all THINGS a global voice.”
  • For the Physical layer (PHY), LoRa uses a modulation scheme called chirp spread spectrum (CSS) and a radio both developed and sold or licensed by Semtech Corporation.
  • About two years ago, Semtech licensed its technology to Microchip and  NXP (like ARM, Semtech now licenses to other semiconductor companies).  As a result, the core LoRa hardware (PHY layer) is no longer provided by a single global chip manufacturer.
  • LoRaWAN defines the media access control (MAC) sublayer of the Data Link layer, which is maintained by the LoRa Alliance. This distinction between LoRa and LoRaWAN is important because other companies (such as Link Labs) use a proprietary MAC sublayer on top of a LoRa chip to create a better performing, hybrid design (called Symphony Link by Link Labs).
  • Many of the LoRa Alliance companies building products are focusing on software defined enhancement and use the LoRaWAN defined MAC.
  • LoRaWAN will most likely be best used for “discrete” applications like smart buildings or campuses, where mobile network connectivity is not needed.

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2.  Sigfox:

  •  Sigfox has designed its technology and network to meet the requirements of mass IoT applications; long device battery life-cycle, low device cost, low connectivity fee, high network capacity, and long range.
  • Sigfox has the lowest cost radio modules(<$3, compared to ~$10 for LoRa, and $12 for NB-IoT).
  • recent announcement from Sigfox noted the addition of a new service called “Admiral Ivory,” that makes possible to connect devices with hardware components costing as little as $0.20.
  • An overview of Sigfox’s network technology is described here.  It consists of: Ultra Narrow Band radio modulation, a light weight protocol, small frame size/payload, and a star network architecture.
  • The Sigfox network is currently deployed in 36 countries, 17 of which already have national coverage.
  • In February, Sigfox reached an agreement with mobile network operator Telefonica to integrate Sigfox’s low-powered connectivity into the Telefonica’s managed connectivity platform.  By complementing Telefónica’s cellular connectivity offerings, with Sigfox’s LPWAN connectivity solution, customers can choose the most appropriate type of connectivity or combine them, implementing use cases and creating new service opportunities that otherwise may not have been possible.
  • Additionally, Telefónica´s managed connectivity platform will integrate Sigfox’s cloud, which gives the company the ability to develop its own end-to-end IoT solutions, based on Sigfox’s connectivity solution and including device integration, as well as data collection and management.
  • While Sigfox is a proprietary IoT network architecture, the company has provided their intellectual property library free of charge and royalty-free to semiconductor companies which have implemented chipsets with dedicated Sigfox interfaces or multi-mode capabilities. The list of chipsets/modules supporting Sigfox (+ multimode) includes:  Pycom (+ WiFi, BLE=BlueTooth Low Energy), Texas Instruments (+ BLE),  STMicroelectronics (+ BLE), Microchip/Atmel, Analog Devices (+ BLE), NXP,  OnSemiconductor (SiP), SiLabs, M2Com, GCT Semiconductor (+ BLE, CatM1, NB-IoT, EC-GSM, GPS), Innocom, and Wisol.
  • The current Sigfox ecosystem is composed of several chipset vendors, device makers, platform providers and solution providers.
  • Here’s a graphic from the Sigfox website on their expanding network footprint:

Sigfox boosts its IoT global footprint, achieving national coverage in 17 countries, and expands into four new countries

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Sigfox’s LPWAN Interoperability using Internet Compression Technology:

In a phone conversation with Sigfox standardization expert Juan Carlos Zuniga last week, I learned that Sigfox plans to achieve LPWAN interoperability at the Application layer, rather than building multi-mode base stations with different radio access networks.  Here’s a glimpse on how that might happen:

At the IETF 98 Bits-n-Bites event, March 30th in Chicago, Sigfox demonstrated IoT interoperability with internet compression technology. which enables LPWAN applications to run transparently over different IoT radio access network (RAN) technologies.

To achieve this milestone and enable IP applications to communicate over its network, Sigfox and Acklio implemented Static Context Header Compression (SCHC) -a compression scheme being standardized by the IETF IPv6 over LPWAN working group*, which Juan Carlos participates in.  SCHC allows reducing IPv6/UDP/CoAP headers to just a few bytes, which can then be transported over LPWAN network small frame size for low-power, low-cost IoT applications.

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*  The focus of the IPv6 over LPWAN working group is on enabling IPv6 connectivity over four different Low-Power Wide-Area (LPWA) technologies: Sigfox, LoRa WAN, WI-SUN and NB-IOT (from 3GPP).

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The demonstration platform was based on an Acklio compression protocol stack running on Sigfox-enabled devices and cloud-based applications over the live Sigfox network in Chicago. Two scenarios were demonstrated: 1] CoAP requests to legacy IP LPWAN devices, and 2] CoAP interoperability over the live Sigfox and cellular networks in Chicago with IP enabled endpoint devices.

“We are thrilled with this latest milestone in our quest to support and promote interoperability in the IoT,” said Juan-Carlos Zúñiga, senior standardization expert at Sigfox and co-chair of the IETF IntArea working group. “It is critical that the industry rallies together to adopt open internet standards to unlock the true potential of the IoT.”

Compression based technology for LPWAN application interoperability builds on Sigfox’s commitment to supporting the development of IoT interoperability as an active member of standards development organizations including the IETF, ETSI and IEEE 802.  And the number of chip companies providing Sigfox network interfaces (see above list) is equally impressive.

References:

https://www.iotforall.com/a-primer-for-loralorawan/

https://www.sigfox.com/en/news/sigfox-pioneers-internet-things-interoperability-further-accelerate-mass-market-adoption

https://techblog.comsoc.org/2017/10/03/sigfox-boosts-its-iot-global-footprint-achieving-national-coverage-in-17-countries/

https://techblog.comsoc.org/2016/05/23/iot-world-summary-part-iii-too-many-wireless-wan-lpwan-standards-specs/

 

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Juan Carlos will be following up with a blog post on LPWAN application layer interoperability as well as a more detailed description of the IETF work on LPWANs.