What you’ll learn:
- Why there’s a need for common standards for wireless communication in smart-home applications.
- The pros and cons of wireless network protocols, including Zigbee, Bluetooth, Wi-Fi, Matter, Thread, and Proprietary standards.
- What the future of wireless network standards for the smart home might look like.
For those of you with a long memory, the genesis of the smart home began in the late 1980s or early 1990s, when the jargon word was “domotics.” At that time, none of the current low-power wireless network standards had been invented. Thus, progress with home automation was very slow and extremely fragmented in terms of the wired and wireless protocols used.
However, wireless technology has become increasingly present in most homes for some time now. Wireless speakers are commonplace. Many electronic units are controlled by a remote control of some type. Houses that owners would not think of describing as “smart homes” may have multiple wireless connections, used for things like heating control, watching the TV, and controlling air conditioning.
In a smart home, the difference is that these diverse devices are connected via a common system, and perhaps through the internet to a remote location. For example, you could turn on your home heating system when you leave work, to warm up your house on your arrival. This saves you from heating an empty house unnecessarily.
To do this, and allow different vendors products to be connected, you need common standards. The issue hasn’t been a lack of standards, but too many of them. This article examines the different standards that have been or are being proposed for smart-home applications and what might be the future path.
Aging Zigbee
The traditional wireless standard for this kind of application was Zigbee—a “mesh”-based protocol for linking wireless devices. It’s been adopted in various industrial automation applications and gained some traction in the smart home domain.
The main issue with Zigbee is that it’s showing its age. The standard originated in a “pre-IP” world. It’s proprietary from top to bottom and has a relatively limited installation base. The basic data rate is also low and requires a router device to define paths through the network.
The relatively small installed base means it has never been adopted within the mobile phone world. In summary, while technically Zigbee was a decent solution for its time, the world has moved on.
Ubiquitous Bluetooth
Bluetooth is a technology that’s seemingly everywhere with the multitude of Bluetooth-controlled devices. For instance, smart light bulbs can be controlled by a phone, and various other controls are now Bluetooth-based. So, it might seem natural to use Bluetooth as a basis for the smart home.
The issue is that Bluetooth was always designed as point-to-point protocol. While you can have more complex technologies such as a star network or even star of stars, it was never designed to be a peer-to-peer type of network.
As a result, along came Bluetooth Mesh, designed as a peer-to-peer network. The problem is that it only has a passing resemblance to Bluetooth itself. It uses the same physical transport layer at the radio level, but otherwise is a completely different protocol. Moreover, it’s not particularly efficient or supportive of high data rates.
It has gained some traction for lighting solutions, which arguably it was designed for. However, it isn’t clear if Bluetooth Mesh can support the full range of potential smart home needs.
Omnipresent Wi-Fi
Wi-Fi is omnipresent in the home, so using it as the backbone of a smart-home system seems to make sense. There’s bandwidth to burn, after all. However, this isn’t really a solution either. Wi-Fi is just a basic data-transmission standard. It doesn’t help devices communicate at the application level.
More fundamentally, all of that bandwidth comes at cost. It isn’t very well adapted to low-power devices. Nobody wants to be continually changing batteries or recharging things. In addition, Wi-Fi isn’t well adapted to dense networks since it operates on a limited number of radio channels. As device nodes proliferate in the home, it risks grinding to a halt.
The new Wi-Fi 6 standard tackles these issues to some extent. It offers much better support for dense networks of low-data-rate devices. Wi-Fi 6 improves power consumption to some degree, but nevertheless it isn’t at the Bluetooth Low Energy (LE) level of battery efficiency.
Proprietary Smart-Home Environments
In parallel to the core protocol side, the big device manufacturers have developed their own smart home environments—Apple’s Home Kit, Samsung Smart Things, Google Assistant, Philips’ Hue, etc. This is fine if you’re happy to commit to an “Apple Home” or a “Google Residence.” However, many customers don’t want to be tied that way. They fear either backing the wrong standard or being captive to higher prices from a monopoly supplier.
Thread and Matter
One might think that manufacturers would be content with a set of “tied” customers, but not if that inhibits the market. In general terms, there’s enough history to show the value of creating interoperability to expand the size of the market rather than clinging on to a segment of a smaller one.
Hence, enter “Thread” and “Matter”—the industry’s “grand unification” plays in the smart-home market. What are these protocols, and do they offer a solution?
Let’s start with Matter. This is an application-layer protocol designed for the smart-home market. The idea is that you provide a common way of interacting with the different types of devices, such as lights, entry systems, heating, and ventilation. In this sense, it’s like the concept of Bluetooth Profiles. Just as a phone can connect to a heart-rate monitor from a separate vendor by using a Bluetooth Heart Rate Profile, your Matter-enabled device or phone can control your heating system, via a set of command commands and responses.
To tackle the wide variety of devices that exist in the home—anything from large mains-powered items like a heating unit or kitchen appliance to a battery-powered temperature sensor—the aim is to separate this application layer from the underlying transport. Thus, devices can communicate Matter-based instructions over Bluetooth, Wi-Fi, Ethernet, etc., depending on the data bandwidth requirements and power consumption needs of the device in question.
Matter tackles the interoperability part. In terms of an underlying protocol, as stated above, you can use existing standards like Bluetooth or Wi-Fi. However, Thread is a mesh protocol specifically designed for this environment. It’s Zigbee updated for the 21st Century.
Thread is IP-based and allows for relatively easy internet access if you want to go out of the home. The protocol is designed to operate efficiently in device-dense environments. It connects to the internet via one or more Thread border routers. Unlike Zigbee, you’re not limited to a single router device.
In terms of hardware, plenty of chips already have Thread protocol stacks running on them. Many devices can run Thread and Bluetooth stacks at the same time, enabling designers to easily implement flexible devices. So, you could, for example, have a device to interact with locally via a Bluetooth point-to-point connection, perhaps to set it up in the first place, and then later connect remotely via Thread.
Future of Smart-Home Wireless Standards
Do Thread and Matter represent the holy grail of smart-home integration? Flexible, interoperable, interconnected, and resilient? In my view, it’s a cautious “yes.” They’re designed to tackle the problems that exist in previous generations of technology. And they’re adapted to the modern world of the internet and ubiquitous IP networks.
The caution and the caveats arise from the “interoperable” part. Interoperability is easy to specify, but a lot harder to make seamless in practice. The experience of Bluetooth is that it took many years to get this working. It also needs genuine commitment by the manufacturers to interoperability. That means not merely paying lip service to the idea, as well as keeping certain functions hidden or frequently changing specifications to make it impossible for third parties to engage.
There’s also the issue of getting the security aspects right. Though opening your home to the internet has some potential physical security benefits, it also carries huge data security risks that could quickly undermine market confidence if not properly addressed.
We are in the early days of this next phase of smart home technology. While the ideas seem good, the hard work is doing it, and doing it right.