IoT driving revival in low-power wide area network technologies.
During my two decades in the mobile industry, the collective focus has been on building faster, fatter networks to support ever-growing mobile voice and data traffic.
The 2G, 3G, and 4G networks have all been at least partly deployed in spectrum cannibalized from slower, narrowband machine, and paging networks including Mobitex, DataTac, Ardis, and CDPD. Even 2G GSM is awaiting its sunset.
Yet, in the background, technology companies have been quietly developing low-power wide area networks designed specifically for machines. These networks are markedly different than networks designed for human communication and entertainment.
SIGFOX’s device-only networks, deployed across Western Europe and soon coming to the U.S., support a maximum payload of only 12 bytes. Meanwhile, Multitech is working to throttle its Conduit networking gear, based on Semtech LoRa chipsets, down to a network speed of 1,200 baud (1,200 symbols/second)—a speed similar to early 1990s dial-up modems.
This renewed emphasis on low-power machine networks comes at the same time when global cellular networks are standardizing on LTE. LTE is great for high-bandwidth, low-latency applications such as streaming video, but its capacity and power levels do not efficiently support small-payload data sources such as sensors. A sub-100K payload hardly justifies the power needed to spin up an LTE session.
Overhead associated with customary network protocols also contribute to machines’ mis-fit with mobile broadband networks. Trying to connect another 20-billion-ish devices to the Internet using TCP/IP (transmission control protocol/Internet protocol) would cause, in Multitech’s VP of Business Development and Communications Bryan Eagle’s words, “the biggest denial of service attack, ever.” Low-power, low-overhead, and low-payload networks are needed if the full vision of the Internet of Things is going to become a reality.
SIGFOX, LoRa, and Weightless-N are three machine-only networks currently in deployment. All three offer an average coverage range of 3-10 miles per base station, device battery life of 5-10 years, sub $10 chipsets, and airtime rates as low as $1 per year. Sub-1,000 Mhz unlicensed spectrum gives these networks excellent RF (radio frequency) propagation, including inside buildings and underground.
Long-battery life comes from “stateless” end points: unlike a mobile phone which is “always on,” devices connected to these networks spend most of their life asleep, waking up periodically to report data and receive updates. Large coverage areas means fewer base stations: SIGFOX covered all of France with about 1,000. Plus relatively low base station pricing—$3,000-$5,000 each—makes these networks inexpensive to deploy.
SIGFOX operates in simplex mode, meaning that the network supports only incoming data transmissions. Security is enabled through multiple layers of device signatures. Simplex networks present unique management challenges, such as keeping endpoints current through software and firmware updates. Nonetheless, SIGFOX is enjoying wide acceptance for a variety of use cases including smoke alarms, tank monitoring, and utility metering. SIGFOX is planning an upgrade to two-way operation, timing TBD.
Another new contender in the IoT network market is LoRa from Semtech. Short for “long range,” LoRa offers all of the benefits of the new class of networks—low-power, overhead, and cost—plus numerous advantages including two-way communication, jamming, and fading resistance, and dynamic bandwidth assignment that enables transmission speeds up to 20 K/second.
LoRa gateways maintain endpoint awareness via a lightweight MAC (machine access control) layer, with security provided through a standards-based exchange of rotating keys. In addition to high-profile trials at mobile industry venues such as Mobile World Congress, the technology is also popping up in enterprise applications such as airport package tracking. The roster of LoRa Alliance members includes IBM, Cisco, Multitech, and Actility.
In contrast to proprietary protocols SIGFOX and LoRa, Weightless-N is an open standard for machine wide-area networking.
Weightless-N delivers 20-bit payloads at speeds up to 100 baud, using a network schema that increases the number of endpoints a base station can support by selecting carrier channels based on surrounding radio frequency “noise.” Security comes through a standard key protocol.
Weightless-N, slated for release during this summer, will first come to market inside modules, modems, and base stations manufactured by nWave.
nWave gear uses Weightless-N for device uplinks, and CDMA for a robust downlinks.
The technology has been privately deployed in conjunction with British Telecom, per nWave CEO Jonathan Wiggin, and also in the high-profile Milton Keynes, U.K. smart-city trial.
It will be interesting to watch how proprietary vs. open standards develop in the IoT market.
William Webb, Weightless SIG (special interest group) CEO asserts, “Only open standards can survive in the space” because “while proprietary standards grow faster than open standards, once an open standard is big enough, the others will adopt it.”
nWave’s Wiggin echoes: “The IoT depends on rich ecosystems, sharing expertise to move the IoT forward and accelerate adoption. Increasing the number of endpoints [using a network protocol] is good for vendors, while increasing the number of vendors is good for consumers.”
In my view, the IoT market is big enough that all of the network competitors should survive—and more. Network diversity is a good thing, especially when it comes to the Internet of Things.
Laurie Lamberth led M2M business development for Nextel and Sprint Nextel for many years, in addition to other strategic partnering and marketing positions. She currently leads the M2M/IoT consulting practice for 151 Advisors. Learn more about Laurie and 151 Advisors at www.151advisors.com
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