Navigating the Next Phase of Low-Power IoT Connectivity

By Lee Ratliff, Principal Analyst , Low Power Wireless

The past year has been an eventful one for the ZigBee standard and ecosystem. The ZigBee Alliance announced major cooperative agreements with competitive standards, EnOcean and Thread. The ZigBee 3.0 revision of the standard was ratified. The Alliance made a major push into the China market, launching a member group on China and adding a number of Chinese companies to the membership, including the addition of Wulian and Midea Group to the Board of Directors. Finally, the ZigBee Alliance announced JupiterMesh, a sub-GHz Neighborhood Area Network (NAN) based on 802.15.4g and aimed at industrial IoT applications including smart meter data backhaul.

zigbee_cntrlworld_vert_cmykAn Inflection Point: The Rise of Low-Value IoT Applications
Of course, all of this activity serves a purpose. The ZigBee Alliance and its membership are positioning the standard to succeed in the next phase of IoT connectivity which will be characterized by new markets, new applications, increased demand, and increased competition.

For much of the past 10 years, ZigBee has enjoyed the position of being the only low-power wireless standard addressing the requirements of the breadth of the IoT. There has been competition, of course, but the success of those competing standards has been limited by technological shortcomings, the degree to which their standard is open, by lack of diversity in their ecosystem, or simply by a focus on a single vertical market. ANT+, Bluetooth, EnOcean, ISA100.11a, WirelessHART, Z-Wave, and others have served as competition to ZigBee to some degree in some markets. But only ZigBee has had the technology, ambition, and the backing to address the low-power connectivity market for the broader IoT.

Until today. We’re at an inflection point in IoT connectivity. Advances in wireless semiconductors, solid state sensors, and microcontrollers have enabled compact and low-cost IoT solutions, bringing the benefit of connectivity to low-value applications. High-value applications have always been able to bring the necessary resources to bear to solve connectivity problems. After all, if the net present value of the node’s data is, say, $1,000, isn’t it worth spending $100 on a connectivity solution? Laying cable or deploying cellular M2M solutions have served well for these high-value applications.

But what if the data is only worth $20? Or $5? Low value applications have largely gone unserved due to the impractical economics of the past. That’s all changing now. Low-cost electronics have made it possible to achieve connectivity solutions with bills-of-material as low as $1 or even less. Combined with more capable back-end systems, data centers, and big-data analytics, it is now becoming possible, and practical, to connect very low-value nodes. This is expanding the market incredibly and attracting competition.

A Whole New Level of Competition
The new breed of competition is formidable. Bluetooth, Wi-Fi, and Thread have all set their sights on the low-power IoT. Importantly, these standards have had the benefit of observing what has worked and what hasn’t worked for ZigBee, increasing their chances of success and reducing the time needed to develop a viable solution.

Thread was designed from the ground up to serve the needs of the resource-constrained IoT. Low power consumption, mesh topology, native IP support, and good security are key characteristics of the standard. Having been developed by many of the same people and companies that created ZigBee, Thread is intended to take the best of ZigBee and improve upon it. Key to Thread’s strategy is end-to-end IP support and that is the primary differentiator as compared to ZigBee. Thread’s stated ambition is the smart home, but there is no reason to believe it will stop there if it’s successful.

Bluetooth and Wi-Fi are potentially even more worrisome for ZigBee. Bluetooth started preparing to address the IoT market at least six years ago when they added Bluetooth Low Energy to version 4.0 of the core specification. The Bluetooth SIG added IP support in version 4.2 of the specification and later this year the 5.0 revision will add increased range and speed, resolving key shortcomings. Around the same time, the Bluetooth SIG will introduce mesh networking standards, which will be backward compatible with silicon designed for the 4.0 version of the spec. Reports indicate that the first version of Bluetooth mesh will be a flood-based network, requiring every node to wake up and relay every message. This reduces power efficiency, but is suitable for mains-powered applications such as lighting, an early target market for Bluetooth Mesh. A second version of the mesh standard will add routing capability, allowing low-power leaf nodes to remain asleep while other (hopefully mains-powered) nodes perform message handling.

The Wi-Fi Alliance is late to the low-power IoT party, but like Bluetooth, it has ubiquitous brand recognition and an enormous ecosystem to help bring it up to speed quickly. The Wi-Fi Alliance announced HaLow, built on the sub-GHz 802.11ah standard, in January 2016 as their entry into the crowded field of IoT standards. HaLow has serious obstacles to overcome. The 802.11ah specification has yet to be approved and a HaLow certification program is not expected until 2018, so it is years behind competing standards. More importantly, in order to leverage the power of the Wi-Fi ecosystem, HaLow needs a large installed base of Wi-Fi access points that support 802.11ah. That means the makers of broadband gateways, wireless routers, and access points need to add a new spectrum band to their products, adding cost and complexity. And sub-GHz bands aren’t universal like the 2.4 GHz band, so manufacturers will need to comprehend the regulatory idiosyncrasies of dozens of countries in their products. Will that happen? Perhaps. Will it happen in time for HaLow to be successful? Time will tell.

Some dismiss Bluetooth and Wi-Fi as recent interlopers in a market they don’t understand and aren’t equipped to address. That is a mistake. The history of connectivity is littered with the corpses of incumbent, technologically superior standards which have had the misfortune of being in the path of a connectivity behemoth such as Ethernet, USB, Wi-Fi, or Bluetooth. These “invasive species” use the power of their installed base to gain competitive advantage in adjacent markets, co-opting the technology of their rivals and leveraging economies of scale to crush opposition. (As a former evangelist for FireWire, the author is painfully aware of this dynamic.)

Next Steps for ZigBee
Despite daunting competition on the horizon, ZigBee is well positioned for the next phase of low-power IoT connectivity. The preparations of the past year are complete and are critical for the success of the standard.

The ZigBee 3.0 standard promises to make interoperability a natural outcome of designing with ZigBee rather than an intentional afterthought, hopefully eliminating a source of criticism of the past. ZigBee 3.0 is also the culmination of a decade of experience and lessons learned the hard way. The value of this can’t be overstated. Product designers value robust, time tested, and production proven solutions.

The ZigBee Alliance has also hedged their bets by agreeing to work with Thread to enable ZigBee’s application library to operate on Thread’s IP networking layer. This adds an all-IP network option to the ZigBee ecosystem. This may be critically important. While IP adds significant overhead to resource-constrained applications, many in the industry believe that the advantages of end-to-end IP support in the IoT outweighs the drag of IP overhead. In the past year, this sentiment has only increased, giving end-to-end IP support a sense of inevitability throughout the IoT. This cooperation with Thread is good for both parties. ZigBee and Thread have very complementary needs – ZigBee needs lightweight IP support and Thread needs a robust application profile library. This joint effort could lay the foundation for a gradual de facto merger of the standards in years to come if IP support is as critical as many believe, a desirable win-win outcome for the industry and the end user. A ZigBee-Thread alliance may also be necessary to achieve the scale needed to fend off threats from Bluetooth and Wi-Fi.

The Importance of Ecosystems
Over the past two years, an interesting trend has become apparent, one that may be critical to the future of ZigBee. The issue of interoperability has moved up the networking stack. A few years ago, the industry was primarily focused on the networking layer to solve interoperability problems. This thinking was a result of the “one winner” connectivity model. That is, a single protocol could “win” the IoT or the smart home, dominating the market and becoming the obvious choice for all products. Since then, OEMs and tech titans like Google, Apple, Amazon, and Samsung have organized higher-level ecosystems, often composed of two or more connectivity protocols, which have moved the concern for interoperability to the application level. Today, it is less relevant that ZigBee and Z-Wave aren’t interoperable at the networking level. With ecosystems such as SmartThings, products using either protocol can coexist within a system with interoperability resolved at the application level.

This model is beneficial for the industry and the consumer. By choosing an ecosystem, the consumer can be assured that certified products will work together despite differences in lower level protocols. Importantly, ecosystems can be made to work together too.

For ZigBee, this phenomenon highlights the need to be included in developing ecosystems. So far, most smart home ecosystems have focused on platform connectivity, often ignoring resource constrained applications. However, as connectivity continues to move into low-value applications, the need to comprehend resource constraints will become more important, pressuring ecosystems to add low-bitrate, low-power protocols. Obviously, ZigBee is a good choice for this application. ZigBee’s greatest asset, its broad and robust application profile library, will play an important role as ecosystems realize the need to control dozens of disparate device types. We’ve already seen the value of the library to Thread, allowing it to bridge the gap to the application level.

ZigBee is entering an era of intense competition, but the reward is immense. Luckily, we know the IoT is not a “winner take all” battleground. Multiple protocols and ecosystems will thrive, finding defensible positions in applications and markets which appreciate their particular combination of characteristics. Wi-Fi is not the solution to every connectivity problem, nor is ZigBee. There is plenty of room for success in the IoT, but there is no guarantee of it either.
IHS_RatliffAbout the Author
Lee Ratliff is a Principal Analyst at IHS, responsible for connectivity technologies and semiconductors. Lee specializes in low-power wireless technologies used in the IoT. Research areas include wireless technologies in vertical markets such as industrial automation, commercial building systems, the smart home, automotive, asset tracking, consumer electronics, PC peripheral, smart toys, and others.

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