Unlock IoT: What’s West of Westeros?
I often find myself in conversations that involve someone wanting to know how to choose between Zigbee, Thread, Bluetooth or Wi-Fi technology? Or maybe LoRa? Or is it better to wait for 5G and NB-IoT (Figure 1)? They all have different standards, which is made more confusing by the (sometimes) unsubstantiated marketing claims about new standard capabilities, like “latency in the milliseconds!” (As if that’s important. Most applications can deal with a latency of seconds. Even live TV delayed a few seconds is still live TV…)
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An overview of IoT wireless standards
So, how does one answer the question, “What standard should be used?” Usually, I answer this question with, “How do you make money?” Because typically, the determining factor isn’t the radio standard. It’s the application, that runs over the wireless.
But maybe I’ll invoke Game of Thrones and start saying “What’s west of Westeros?” instead. Because keep in mind that whatever wireless standard is leading the pack today, in 5-10 years things will have change anyway, so upgrading your network will be important. Waiting for the “final” or “permanent” wireless networking technology will just be an exercise in waiting.
But can we channel our inner Arya (or Bran maybe?) and look toward the future to develop a sense of where things are going? I believe we can.
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3 Radios for 3 Spaces
You may not have thought of it this way, but it’s true. Our smartphones have 4G, Wi-Fi and Bluetooth technology—three radios. It’s technically possible for a smartphone to only have one radio. Not cost-effective today, but possible. For example, you listen to music on your phone with a Bluetooth headset, but, technically, it would be possible to connect both the phone and a headset to the cellular network.
But for now, anyway, we’ve gotten used to having three radios in our smartphones. And we use them in our “spaces” in different ways. We use a Bluetooth radio for our immediate, bodily, personal space—like that Bluetooth headset for listening to music. We use Wi-Fi for our private spaces like home and office—places that are private territory versus public. And we use 3G/4G—and soon 5G—for access in the public space. This division, by the way, just fell into place over the years. Anyone who has been involved in the “war of standards” knows there was no higher committee deciding how to neatly divide different radios and standards over these three spaces.
In the past 20-30 years, every standard has battled for maximum usage space—and some of these battles are still going on. 5G, the next public space standard, is claiming that it works well indoors and may make Wi-Fi redundant. Bluetooth initially made serious claims for the Wi-Fi indoor market (never successful), while Wi-Fi has been eyeing the Bluetooth market with Wi-Fi Direct. Although Wi-Fi Direct isn’t dominant, it isn’t dead either—for drones, Wi-Fi Direct has found an interesting niche.
Applying this to Standards
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There’s a parallel situation developing for low-power IoT standards. Remember that the real focus of these low-power standards is on long battery life—not data rates—without compromising range. Usually, low-power standards are used to connect devices—sensors for example—to the internet (IoT) for the purpose of sharing sensor data, and the data rate required for this is orders of magnitude lower than for “normal” Internet usage or watching videos. Essentially, low-power standards exchange data rate for battery life.
Interestingly, these low-power standards are rallying around the same three ranges mentioned earlier:
• For our personal space: Low-power Bluetooth technology (sometimes called Bluetooth Low Energy)
• For our private space (such as home, office or hotspot): Zigbee (IEEE 802.15.4), which is essentially a low-power Wi-Fi standard
• For the public space: NB-IoT/Cat-X as part of 4G/5G
Combined, Figure 2 shows that system of standards would look like. Not incidentally, this low-power/sense-and-control alignment makes all the sense in the world because it lines up with how we experience spaces with the three radios in our smartphone.
This consolidated view of low-power IoT wireless standards makes sense because it lines up with the three radios in our smartphone and how we those radios.
Not so fast…
But remember, nothing is for sure. Technologies continue to try venturing into “other spaces.” These initiatives can vary from ways to maximize the reuse of existing technology or trying to answer simple questions—like, can NB-IoT/Cat-X also be used for indoor networks? Similarly, there’s an effort to expand Bluetooth Low Energy into the networking space and adding meshing capabilities to displace Zigbee—in the same way that Bluetooth technology tried to displace Wi-Fi around 20 years ago. These efforts may not be successful, but big companies are spending serious dollars on them.
And there may be a fourth space to consider. Something that falls between the local area (indoor) and the wide area (public). There are large outdoor spaces that are still semiprivate, such as campuses, harbors, airports and convention centers. Do we need another standard that is focused on this “in-between” domain? The future will tell. Maybe the existing standards are flexible (and cost-effective) enough to serve this space well. Or maybe an emerging standard will be better qualified. In this respect, it’s interesting to see that LoRa, as a pseudo standard for outdoor, is very visible in this zone between private and public, in harbors and airports.
For standards venturing into other areas, it’s also interesting to mention that the boundary between Wi-Fi (high data rate) and Zigbee (low power) is not very definite. There are applications that require higher data rates and need to run on batteries, thus requiring low power. For some time now there have been significant efforts to make Wi-Fi truly low power. True low-power implementations of Wi-Fi 4 (.11n) and Wi-Fi 5 (.11ac) might be interesting alternatives for Zigbee technology, if they reach low enough power—in other words, long enough battery life.
The takeaway
Ultimately, the usefulness of the application creates the value for the end user, not the wireless “wire.” Only time will tell which standards will be the most successful, but no point in waiting. Go ahead and make money now.
RESOURCES
Published in Circuit Cellar Magazine Issue 349 • August 2019 – Get a PDF of the Issue
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Cees Links was the founder and CEO of GreenPeak Technologies, which is now part of Qorvo, and is now the General Manager of the Wireless Connectivity Business Unit. He was involved in the establishment of numerous standards efforts including the IEEE 802.11 standardization committee and the Wi-Fi Alliance. He was also instrumental in establishing the IEEE 802.15 standardization committee to become the basis for the ZigBee sense and control networking. He was recognized as Wi-Fi pioneer with the Golden Mousetrap Lifetime Achievement Award [1] and more recently inducted into the Wi-Fi NOW Hall of Fame [2].
