IoT standards: Game over

I’m often asked this question: With so many different standards out there, which one should I choose? Zigbee, Thread, Bluetooth Mesh, Wi-Fi, LoRa? Or is it better to wait for 5G and NB-IoT?

Of course, these questions can be confusing and hinder the adoption of the Internet of Things (IoT). As shown in the figure below, part of the confusion is that it is difficult to determine which standard is most appropriate.

Furthermore, marketers make unrealistic performance claims about the new standard, such as latency (“less than a few milliseconds!”), as if it were really necessary. It’s not. Most applications can tolerate a few seconds of latency; even if live TV is delayed by a few seconds, it’s still live TV.

So how do we answer the question, “Which standard should we use?” I usually ask, “What do you rely on for profitability?” Generally speaking, radio standards are not the determining factor for profitability. For radio, it is mostly “good enough” and profitability depends on the value created by the applications running on the wireless network. A wireless network is just a wireless network, just like wires are just wires.

Remember: whatever wireless standard is today, things may be different in 5-10 years, so upgrading your network is critical. But it will still be a long time before the "ultimate" wireless networking technology emerges.

So can we look ahead and make some predictions about where things are headed? I believe it is possible, but first some perspective is needed.

Our smartphones come with three radios (4G, Wi-Fi and Bluetooth). Why three, and not two (like tablets), or one, or four? It’s because the variety of radios has to do with technology and our psychological attitude toward different living spaces. Let me explain.

First, technology. Radio performance depends largely on three factors:

The fourth factor is usually cost, with a simple rule: "the more, the more expensive".

In other words, greater range is usually more expensive; the same goes for higher data rates and longer battery life. However, technically it is possible to have just one radio; it may not be cost-effective, but it is an option.

Second, how do we experience space?

This has less to do with technology and more to do with psychology. At the smallest level, the first thing we experience is personal space. Have you ever had someone talk too close to you and made you uncomfortable? If so, you know what I mean by "personal space." It's like an elastic bubble that moves with you and changes size all the time; if you're on a busy subway, your personal space is much smaller than in a restaurant or office.

Space can also be defined by the distance that can be reached through sound or vision. Such a space might be a home or an office. It is a private territory compared to the outside world. We sometimes distinguish between different spaces, such as indoors and outdoors, or private and public spaces.

In addition, there are outdoor public spaces that are owned and managed by the government.

If we map these three spaces to the three radios in our phones, there’s a sense of continuity: Bluetooth radio for personal space (our bubbles), Wi-Fi for private space, and 3G/4G and the upcoming 5G for connectivity in public spaces.

Coincidence? Probably not. Anyone who has participated in the "standards war" knows that there is no supreme committee that decides how to divide the three spaces among different radios and standards. All standards are established by convention.

Each standard has fought for a larger share of the space over the past 20-30 years, and some of these battles continue today. 5G, the next generation public space standard, claims to work well indoors, potentially obsoleting Wi-Fi. Bluetooth initially had its sights on Wi-Fi’s indoor market (never succeeding), and Wi-Fi has been trying to take over the Bluetooth market with Wi-Fi Direct. While Wi-Fi Direct didn’t win dominantly, it didn’t die either, and found a niche in drones.

So, by now we understand at least why phones need three radios and how they fit seamlessly into the way we experience space. But with so many low-power IoT standards, how do we choose? First, we need to understand the market for low-power standards.

The real purpose of low-power standards is to extend battery life without affecting range, not to increase data rate. Typically, low-power standards are used to connect devices (such as sensors) to the network (IoT) to share sensor data, and the data rate required for this process is several orders of magnitude lower than the data rate required for "normal" Internet use or watching videos. So, in essence, low-power standards extend battery life by sacrificing data rate.

Interestingly, these low-power standards are also beginning to cover the three ranges mentioned above:

Therefore, the answer that can point out the development direction of various standards and calm the heated industry discussions may be:

This low power/sensing and control compatibility makes a lot of sense because it corresponds to our experience space and the three radios on a smartphone.

However, nothing is certain and looking into the future is a risky endeavor. Various technologies continue to try to enter the “other space” and several initiatives are being pursued in the market. These include maximizing the reuse of existing technologies or simply experimenting (e.g., can NB-IoT/Cat-X also be used for indoor networks?).

Similarly, there are attempts to extend Bluetooth Low Energy into the networking space and add mesh capabilities to replace Zigbee, just as Bluetooth tried to replace Wi-Fi 20 years ago. These efforts may not succeed, but companies are investing heavily in them anyway.

It is worth noting that there may be a fourth domain between the local domain (indoors) and the wide domain (public areas). Some large outdoor spaces are still semi-private, such as campuses, ports, airports and conference centers.

So, the question is: do we need a new standard for the “in-between” domain?

The future will tell. Perhaps existing standards will become flexible (and cost-effective) enough to meet this spatial need, or new standards will emerge that are more suitable. It is worth noting that as a pseudo-outdoor standard, LoRa has shown some advantages in the middle domain between private and public areas, especially in ports and airports.

Next, I will introduce the role of open standards and proprietary standards. History has shown that open communication standards are often more successful than closed standards . Wi-Fi squeezed HomeRF out of the market; similarly, BLE eliminated ANT+.

But other standards are still in fierce competition, such as Zigbee, Thread and Z-Wave (Silicon Labs). However, Zigbee and Thread are based on the open IEEE 802.15.4 standard (just like Wi-Fi is based on the IEEE 802.11 standard), while ZWave is a proprietary, closed standard. It is still unknown who will win, but it is likely to be a combination of Zigbee/Thread; the two standards already use the same application layer software (Dotdot), and the only difference is the network layer software.

Regarding standards branching out into other areas, it is worth noting that the line between Wi-Fi (high data rates) and Zigbee (low power) is not clear either. From an application space perspective, there are applications that require higher data rates while also needing to use batteries, and therefore also require low power.

There have been efforts to reduce the power consumption of Wi-Fi for some time. IEEE 802.11ah is an example, although it seems unfeasible because it operates in the sub-GHz band and lacks consistency; different regions around the world require different radio technologies. However, if Wi-Fi 4 (.11n) and Wi-Fi 5 (.11ac) can reduce power enough, in other words, the battery life is long enough, their low-power versions may become alternatives to Zigbee.

These are the future trends and headlines that radio developers need to know. However, the same rule remains true: Ultimately, it is the usability of the application, not the wireless network, that creates value for the end user.

Only time will tell which criteria are the most successful, but if you know how to profit now, there’s no need to wait.

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