The Smart Home’s Pursuit of Interoperability

Market analysts predicted that 2017 would be the year of the smart home. Since then, consumers have seen a flood of smart thermostats, connected security systems, smart appliances and intelligent lighting systems. By the beginning of 2018, however, research firm Gartner found that smart home technology adoption remained slow. Only 12% of users in the UK, U.S. and Germany had deployed some form of smart energy controls—such as thermostats or lighting—and another 7% had some type of smart home access device, such as smart door locks, according to the research firm.

Although industry experts continue to predict solid growth in this arena, the unanswered question remains: Why is smart home technology taking so long to gain momentum? Closer examination seems to indicate that one of the factors slowing growth is the ongoing issue with fragmented communications technology. Simply, there are too many choices and too little interoperability.

The Trouble with Fragmentation

The absence of interoperability has hindered adoption on several levels. These range from functionality to the nuts and bolts of deployment.

A key advantage of many of the smart home hubs is that they enable system-wide compatibility. For example, the Atmos smart home control platform shown here is compatible with Wi-Fi, Bluetooth, Bluetooth Low Energy, Zigbee, Z-Wave and even infrared. Image courtesy of Atmos Home Tech.

In terms of functionality, many devices entering the market today do not meet consumers’ expectations. Although the devices connect to the internet, they often cannot communicate or work with each other. This is a problem because simply providing the ability to remotely control devices via an internet connection is not enough. A key value of the smart home lies in devices’ ability to work with each other. It amplifies the strengths of each device by leveraging those of the other systems in the home automation ecosystem. In short, the whole benefit is greater than the sum of its parts.

As for deployment, the absence of interoperability foils adoption. Before users can get today’s home automation systems up and running, they must sift through a wide assortment of wireless technologies to identify the products that best meet their needs and work well within the system already in place. But users should not have to do a deep dive into the details of the various wireless standards to find one that can bridge the gap between all of their favorite devices. The frustration of trying to deploy a hodgepodge of technologies sets a negative tone for the users’ experience and all too often stops users in their tracks.

“Interoperability is the biggest hot-button topic in the industry currently, and the biggest challenge,” says Mark Lyle, founder of Atmos Home Tech. “The average homeowner, for the most part, does not have the necessary time or understanding to research which products or protocols will work together seamlessly. In many cases, the customer purchases multiple smart devices only to get them home, struggle for hours to configure them and then realize they are not compatible. This is clearly not the path to mainstream adoption. To realize the full potential, device manufacturers need to develop products that communicate with and complement each other.”

No One Interoperability Standard Meets All Needs

To get a clear idea of where the leading wireless technologies fit into the smart home ecosystem, it’s necessary to examine the essential features of a smart home network.

The optimal system would support high data throughput for streaming applications, as well as enable intermittent bursts of small packets of sensor data. It would consume enough energy to support high throughput, but support low-power applications, too. Signals would be encrypted to ensure security. Furthermore, the network architecture would be able to handle a large number of systems and allow users to easily add new devices as needed.

Herein lies the problem: There are a number of excellently crafted wireless standards. As a matter of fact, there’s a standard to meet each of these requirements. What is still elusive, however, is one that simultaneously meets all of the requirements.

Wi-Fi Power Problems

A good example of this conundrum is Wi-Fi. This wireless standard is a popular connectivity option for the smart home because it is already available in nearly every home. Wi-Fi offers WPA2 security, as well as speeds up to 800 Mbps. Essentially, the technology is a whole-home network, ideal for heavy-lifting applications like media streaming, web browsing and other large data transfers.

On the downside, however, is that Wi-Fi consumes a lot of power. As a result, many smart home device developers steer clear of Wi-Fi connectivity because it requires a dedicated power source or a long-lasting battery.

Wi-Fi also falls short in other areas. For example, just because Wi-Fi can theoretically connect 255 devices to a single Wi-Fi router or access point doesn’t mean it is practical. Each device added to the network reduces the bandwidth available to the other devices using the same internet connection. This can create a bottleneck where traffic passes through the internet router.

That said, Wi-Fi developers do not plan on being outdone by competing standards. A new standard called 802.11ah (HaLow) offers a low data rate and supports long-range transmissions. In addition, the next standard for wireless LANs, 802.11ax, promises to extend battery life. Although the new features could expand Wi-Fi’s capabilities for smart home applications, the new specifications still have to establish a presence in the market.

Bullish on Bluetooth

Another standard with a large installed base is Bluetooth. The standard is well-known to users and offers moderate bandwidth. Because it uses frequency hopping and government-grade encryption to ensure that no one can intercept or unscramble interactions with smart home devices, Bluetooth is very secure.

In terms of supporting low-power applications, Bluetooth LE uses very little power compared with Wi-Fi. This makes the standard a good fit for one layer of smart home applications.

Until recently, however, developers shied away from using Bluetooth in smart home systems because of its short-range transmissions. That changed with the latest release of the standard, Bluetooth 5 in July 2017. This version adds mesh networking capability, which enables many-to-many device communications and serves large-scale device networks well.

The latest specification changes to the specification could make Bluetooth a stronger contender for the smart home.

Zigbee and Z-Wave

The Zigbee and Z-Wave standards are similar in their general performance and the applications that they target. Both specify very low-power networks and support mesh networking.

The use of mesh technology makes the two standards particularly desirable for smart home applications. The inherent nature of mesh networks gives Zigbee and Z-Wave the range required to support widely distributed devices. Mesh and the standards’ low-bandwidth communications also prevent significant signal loss, bolstering the technology’s reliability. The low-bandwidth performance also makes the standards ideal for simple devices, such as motion sensors, that require only data connections for on/off control functions.

It’s important, however, to remember that there are differences between the two technologies. For example, Zigbee has a range of 10 meters, whereas Z-Wave can reach 30 meters. Z-Wave supports throughput rates of 100 Kbps. In contrast, Zigbee delivers speeds as high as 250 Kbps. Perhaps the greatest differentiator lies in the fact that the two specifications are not compatible with each other. In fact, Z-Wave is a proprietary system, and Zigbee is an open standard.

Although Zigbee and Z-Wave target the same general application requirements, each has a different focus. For instance, Z-Wave’s primary focus has long been on monitoring and control functions in the home. It is widely used for lighting control, security and climate control. Zigbee on the other hand has—until recently—leaned toward industrial applications and is well suited for scenarios that require infrequent data exchanges within a 100-meter range.

Most home automation device makers have chosen the smartphone as their control interface. The downside of this is that with each connected device having its own app, interacting with multiple devices becomes cumbersome. By deploying a hub with its own app, controlling smart home systems becomes more efficient. Image courtesy of Atmos Home Tech.

Both of the specifications boast ease of deployment. Zigbee has network profiles readily available, which can minimize development time for common applications. However, it is more complex, which can extend deployment time frames. In contrast, Z-Wave is a simpler protocol, so development can be faster and less complicated.

One problem that arises with Zigbee and Z-Wave networks, however, is that their signals aren’t directly compatible with most computing devices, such as smartphones and laptops. As a result, devices like light bulbs, locks and motion sensors must communicate via an intermediary device.

Is Interoperability Within Reach?

So the question is: Given the diverse collection of protocols and systems on the market today, what level of interoperability can users achieve with current technology?

Many consumers and technology providers appear to be sidestepping the need for individual devices that interact directly with each other, relying instead on intermediary devices to enable communications and coordinated actions. For a number of companies, this translates to using a linguistic bridge that can work with a variety of protocols.

“I don’t believe that the communication standards/protocols are the barrier to interoperability at all,” says Lyle. “Each of them can accomplish specific tasks very well, and if smart products are designed with this in mind, leveraging the strengths of each of these technologies—as opposed to building closed ecosystems of a few products that work well together here and there—I believe that we can achieve compatibility across the board. By combining Wi-Fi, Zigbee, Z-Wave, RF and infrared technologies, we are able to integrate most smart home devices, either via direct interface or through various software application programming interfaces (APIs).”

One of the earliest bridge devices to enter the market was the smart home hub (a.k.a. home automation hub). Hubs are network devices that serve as a convergence point, where data arrives from all the devices in the ecosystem. The hub determines how, when and where data is forwarded, and may have compute resources to perform some processing tasks.

Furthering the cause of interoperability, hubs unify multiple communication protocol capabilities on one platform. “We believe that the hub should combine multiple protocols to enable a greater vision for the smart home, where all devices connect to the home network and can be controlled from a single interface,” says Johan Pedersen, product marketing manager, Z-Wave IoT, for Silicon Labs. “The hub provides the opportunity to unite smart home protocols in a single system.”

These bridging devices also translate low-energy radio signals from Z-Wave and Zigbee devices into communication protocols smartphones can understand, opening the door for single devices that can control not only Z-Wave and Zigbee devices, but all the smart systems in the home.

Hub functionality, however, doesn’t stop at solving the interoperability issue. They also offer scheduling and controls that enable users to automate devices so they work with each other without human interaction. For example, a user could program the system to automatically turn on the lights whenever the front door is unlocked. The hub can also perform more complex tasks, such as using inputs from multiple sensors and switches to adjust devices in the home as required.

Companies ranging from Samsung and Wink to Atmos offer hubs with a variety of features. These products support varying combinations of protocols, including Wi-Fi, Bluetooth and Bluetooth Low Energy (BLE), Zigbee, Z-Wave and even infrared.

At the same time vendors are pursuing the uses of hubs and unified controllers, a number of consortia are creating specifications, interoperability guidelines and certification programs, with an eye on effecting change by giving developers tools to deliver compatibility.

“For a truly smart—that is responsive, perceptive and autonomous—home, you need a level of interoperability that historically has only been delivered via standardization,” says David McCall, chair of the strategy work group at the Open Connectivity Foundation. “This does not mean that every device needs to be able to talk directly to every other device, but the systems that deliver ‘smartness’ need to have access to all the data and control points they need—and to each other, since there will probably be more than one system—with appropriate security controls.”

Future Smart Home Interoperability

Well-established wireless networking specifications like Wi-Fi, Bluetooth, Zigbee and Z-Wave continue to vie for a piece of the smart home market, each offering credentials in their own key performance areas. Further complicating the bid for dominance, each of these specifications is a work in progress, with developers adding features that make the protocol more competitive.

802.11ax makes Wi-Fi more appealing for applications involving low-power devices, and Bluetooth 5 adds mesh to its strengths, enabling the technology to provide greater range. Adding to the fluidity of the situation, there are new protocols being introduced, such as Thread, the latest low power, mesh technology. The truth is, anyone waiting for one standard to attain dominance in the smart home sector may have a long wait.

A more likely scenario is a hybrid network architecture, in which Wi-Fi is paired with a low power, mesh protocol well-suited to handle communications of devices like sensors. “The optimal network architecture in a smart home environment needs to provide two types of connections: internet connectivity to the household and appliance connectivity to the network,” says Luca Gaetano Capula, CEO of ALYT. “These two networks must be separated for several reasons, ranging from security to efficiency and performance.”

In addition, middleman-type devices will play a key role. Once thought to be the answer to smart home’s interoperability problem, however, smart hubs now face competition from newcomers like Google Home, Amazon Echo and Apple Homekit. The attraction of these devices lies in smart assistant platforms like Amazon’s Alexa and Google Assistant, as consumers increasingly come to expect more natural interfaces. That said, stand-alone hubs offer a rich feature set that smart speakers cannot match.

All things considered, the smart home ecosystem is still in its development stage, and the concept continues to struggle to gain traction, leaving much of the story still unwritten.