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Just as the "last mile" was a challenge for the early years of internet connectivity, the last few miles -- or the last few feet depending on the application -- matters to would-be IoT implementers. Whether it's technology for the home, transportation systems, agriculture, factory or distribution, deployment teams have found much confusion and many competing technologies and vendors.
There are plenty of ways to deliver the moderate amounts of bandwidth that most applications need, but longer-term buildouts bring questions of cost, reliability and performance to the fore. Wired solutions sometimes work despite their logistic impracticalities, but they are usually less flexible, let alone more costly to install and maintain. Bluetooth and Wi-Fi may seem like good choices, but they can be insecure and, because they use a crowded range of the radio spectrum, are subject to interference. Wireless or not, power limitations mean many IoT applications only become practical when a device can sleep most of the time, waking up only when needed.
Now, thanks to an accumulation of interest in Narrowband IoT, or NB-IoT, some see connectivity via the ubiquitous cellular network becoming a more viable option. In fact, European cellular carrier Vodafone announced in October that it would launch NB-IoT in four European markets -- Germany, Ireland, the Netherlands and Spain -- in Q1 2017. The company also committed to rolling out the network standard across all of the countries in which it operates by 2020.
To be sure, there are other technologies with a head start in serving the same use cases, generally bunched together with cellular under the low-power wide-area network (LPWAN) category. Currently two vendors, Sigfox, based in France, and the members of the LoRa Alliance offer non-cellular IoT approaches to LPWAN. What has changed in the competitive picture is that after a slow start, 3GPP, which involves seven different telecommunications standard development organizations, has come up with a slew of agreements that should finally allow telecom carriers to compete in the space and move ahead with NB-IoT.
Narrowband IoT benefits and use cases
Tom Rebbeck, research director at London-based Analysys Mason, explained that Narrowband IoT differs from other LPWAN technologies in several crucial ways. For one thing, unlike Sigfox, LoRa or some of the other competing technologies, NB-IoT uses licensed spectrum. This means that providers using NB-IoT can offer some service-level agreements, which makes it more likely to be suitable for services such as healthcare solutions.
Narrowband is also a standardized technology that reuses most of a mobile operator's existing network. For example, Vodafone has stated that for around 85% of its sites, the move to NB-IoT is "simply a software upgrade, which should help to keep upgrade costs low," he said.
Another important benefit of Narrowband IoT, Rebbeck said, is that it has a wider base of industry support than competing options. "The NB-IoT forum has telecom operators that represent more than 2 billion subscribers," he noted. In comparison, LoRa network operators represent around 200 million subscribers, and Sigfox operators less than 50 million. Furthermore, NB-IoT has the support of Huawei, Ericsson, Nokia, Intel, Qualcomm and others, and so has a broader base of established vendors than the other technologies. Special NB-IoT device chipsets are also coming to the market.
"We expect it to support a wide range of use cases -- much wider than for standard cellular," Rebbeck said. The reason is that it offers a generally lower cost of around $5 per device and $1 per year for connectivity. This will help enlarge the potential market. "The initial interest we are seeing comes from metering, in particular water metering, but we also expect tracking applications such as child and pet trackers, consumer electronics, retail, agriculture and other types of applications to appear," Rebbeck said.
According to 3GPP, other benefits of Narrowband IoT include:
- long battery life: Using a 5 watt/hour battery could last up to 10 years;
- the ability to support large numbers of devices; and
- uplink and downlink rates of around 200 kbps using only 200 kHz of available bandwidth; this is important because it means carriers will not have problems accommodating the service.
Can Narrowband IoT win this standards war?
Andre Kindness, principal analyst at Forrester Research in Cambridge, Mass., compared NB-IoT to the battle between Sony Betamax and VHS in the early years of home video; both had advantages but one proved to be most cost effective. "If you take a look at the cell companies as well as some of your IT connect companies and Wi-Fi and Bluetooth companies, they are all scrambling to go after this market," Kindness said. Each of the competitors is "trying to overcome physics" because they want lower power, longer range and more data -- "and those things will never converge because you have boundary conditions that make it impossible," Kindness said. In that competition, he sees some advantages for NB-IoT, but each of the carriers must embrace it and implement significant changes to their networks to make it a reality.
"As soon as you back away from the basic physics involved, the bigger concern in the industry is proprietary versus open. And the dominant players, Sigfox and LoRa, are both proprietary approaches rather than open," Kindness said. "I have to say, I'm not a big fan of proprietary, but those companies have a big footprint right now. There is also the business question of whether you want to do it yourself, which is possible with open technology, or depend on a carrier," he added. Standards such as Weightless, a set of LPWAN open wireless technology standards developed by the Weightless Special Interest Group, may offer alternative routes to building LPWANs, he said.
Of course, he noted, it may not be an either-or choice.
"It may end up with the adoption of more hybrid type solutions where inside a factory, companies want to manage IoT connectivity themselves, but for an oil pipeline or for meters scattered around a city, they might want to have a carrier involved," he said.
Another factor to consider is that 5G is expected to hit the market around 2021, potentially benefitting Narrowband IoT and cellular IoT.
Rebbeck is optimistic. "We are forecasting over 3 billion connections using LPWAN by 2025 and expect NB-IoT to be a significant part of this," he said. "Clearly we are at a very early stage for NB-IoT and it is hard to know what its impact will be -- I suspect that the combination of low cost, long battery life and strong coverage will open up many new services that we haven't even thought of today."
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