Building a smarter "smart home" on ZigBee 3.0
No longer just gizmos and gadgets for the wealthy, devices for the smart home are fast becoming the purview of the every man. Estimates project that within the next 10 years the average household will consist of 100 connected devices, networking everything from lights and motion sensors to thermostats and smoke detectors.
With every passing day it seems more and more otherwise-mundane household items are being outfitted with connectivity. From refrigerators and washing machines to toasters and light bulbs, appliances of all kinds are being networked and marketed as elements of the impending smart home.
While the smart home architectures of tomorrow will indeed be comprised of numerous networked devices, however, simply Internet-enabling a door lock or light switch doesn't make it inherently "smart." The key to the smart home is harnessing data based on behavior and usage patterns, and using that intelligence to autonomously improve the residents' quality of life. But when comparing today's smart homes with those of the future that operate independently and behind the scenes, Paul O'Donovan, Principal Research Analyst of the Semiconductor Group at Gartner (www.gartner.com) says it's "similar to where the mobile phone was in the 1990s to where it is now – functional, but by no means smart."
"Basically, there is little or no computing or learning going on in the systems available today," O'Donovan says. "There is some limited decision making, such as turning off heating or lights when the home owner leaves the building, but otherwise there is little 'processing' of the data locally or in the cloud."
"The smart home is still in its infancy," says Ryan Maley, Director of Strategic Marketing at the ZigBee Alliance (www.zigbee.org). "There are many products available and these are well deployed extending comfort and efficiency for home owners. However, these products tend to be single-purpose applications such as lighting, security, or energy efficiency. These installations probably reflect where the homeowner has interest or where there is some easily understood value. However, the smart home should be much more.
"As more devices are connected, consumers will see more value than simply extending control of their home to mobile devices," Maley continues. "The smart home should be optimizing efficiency and making decisions for us automatically rather than simply allowing us turn things on and off via a mobile device instead of a light switch. As more everyday objects are connected and become smart, many new interesting applications may arise, such as balancing the needs of lighting and energy management by opening window coverings instead of turning on a light when we enter a room."
To enable analytics for new smart home applications and services such as energy management, embedded software development companies like DSR (www.dsr-company.com) design architectures that amass sensor data from connected devices (Figure 1). In addition, new technologies and techniques are emerging that will add value and make home automation more transparent to the end user, says Genie Peshkova, Vice President of Operations at DSR.
"Consumers expect the smart home to be truly smart – don't ask me about things that you can determine, learn my behavior and adapt," Peshkova says. "Don't unnecessarily disturb me, but do let me know when something is wrong or out of the ordinary. The idea is for the smart home to fit perfectly into the consumer's lifestyle, adapt to his or her likes or dislikes, simplify life, add convenience, and provide much needed security and peace of mind.
"Without analytics and data intelligence, smart home systems cannot learn, intelligently respond, and truly adapt to the consumer," she continues. "As the smart home market continues to grow, data will become a more and more powerful component of the equation. We are working in collaboration with partners that provide behavior analysis engines, content analysis, and voice control – a large degree of automation for the user's lifestyle, social preferences, behavior analysis, and prediction, a lot of which already exists but will become even more sophisticated. Pulling all these together will lead to providing a truly smart solution that will deliver a lot of value to the consumer."
But at the network application layer underlying this infrastructure, interoperability challenges still exist that limit the potential of the connected home.
Application-level interoperability and the fight for the smart home – ZigBee 3.0
Though architectures such as those depicted in Figure 1 generally abstract the application layer through a gateway or router that connects sensors directly to the cloud, application-level interoperability is still key for the many subdomains and devices that make up a fully outfitted smart home. For instance, while standardization at the network-level allows for commonality around packet forwarding, interoperability at the application layer establishes consistent rules for exchanging data between devices (Figure 2). As a point of reference, the latter is similar to how HTML is used across the Internet.
Given this, and the low-power, low-cost, and ease-of-use requirements of consumers, wireless mesh networking technologies have gained prominence as a scalable way of integrating products into the smart home. However, with widespread incompatibility between vendor devices and numerous networking technologies all competing for an emerging market, settling on any one connectivity solution has become a struggle for industry and consumers alike, O'Donovan says.
"Multiple networking technologies clearly complicates the picture for the consumer and slows manufacturer attempts to unify around one or more compatible systems," he explains (Figure 3). "There is little cohesion in the market. Despite efforts to deploy mesh networking by some players as a way to offer a whole home/system solution, there is scant interoperability between most manufacturers."
"There are a number of options vying for the home automation market, with X10 probably known best because it has been around a long time, although ZigBee and Z-Wave are now recognized as the way forward," O'Donovan continues. My prediction is that the winner will always be a widely available, standards-based solution, and in that case ZigBee should dominate."
Though ZigBee has gained traction since being conceived in the late '90s, much of its success and market adoption came as a result of "application profiles" that tailored the technology to certain vertical markets. While these helped ZigBee penetrate new areas and use cases, they also impaired the ability of devices based on different profiles to interoperate seamlessly, which, as mentioned, is a critical consideration in full-blow smart home deployments.
However, in late 2014 the ZigBee Alliance announced the release of ZigBee 3.0, a new standard that unifies the previous ZigBee PRO-based application standards to enable interoperability between home automation, energy management, lighting, appliances, security, health care monitoring, and other smart home devices (Figure 4). Based on the IEEE 802.15.4 standard, ZigBee devices were previously compatible at lower levels of the network, but the advent of ZigBee 3.0 promotes interoperability at the application layer as well to alleviate some of the challenges of device-level interoperability.
"Certainly, interoperability is a key concern because consumers must have easy-to-use and easy-to-connect devices that simply work together," Maley says. "ZigBee 3.0 will allow a wider range of devices to seamlessly interoperate. ZigBee has always provided interoperability among the various domains (lighting, health care), but ZigBee 3.0 will permit a wider variety of devices to connect together, which should simplify the choice for product developers and consumers alike.
"The ZigBee Certified program can help by insuring interoperability between certified devices regardless of the manufacturer," he adds.
With ZigBee 3.0, all of the traditional characteristics of ZigBee devices are maintained, such as the self-healing capabilities associated with mesh networks and power consumption several orders of magnitude less than Wi-Fi, as well as features such as Green Power that support battery-less energy harvesting devices. This last point on power is also a crucial one for the smart home, on the one hand because improved efficiency in one area shouldn't come at the expense of inefficiency in another, and on the other hand the prospect of changing batteries for a house full of connected devices on a regular basis is simply a non starter in the consumer world.
Cost and the "killer app"
As intriguing as application-level standardization is for the advancement of the smart home, architectures that make beneficial decisions based on behavior and efficiency being embraced by the broad market is a question of cost and consumer demand. As O'Donovan notes, "costs are important if you have to pay $1,500 for new lighting that will only save you $50 in energy costs. There has to be a compelling reason to buy into the smart home concept."
On the heels of recent discussions in the California legislature related to regulating the standby power requirements for set-top boxes, Cees Links, Founder and CEO of leading ZigBee chipset and module vendor GreenPeak Technologies (www.greanpeak.com), believes an answer to both is on the horizon (Figure 5).
"Volumes drive down cost, lower costs drive up volume," Links says. "The only question is, "What does it take to kick-start the process? The killer app. From a GreenPeak perspective, we see the killer app as having ZigBee in the set-top box and remote control," Links continues. "First of all, consumers have a better user experience with ZigBee compared to IR, but [because of the power benefits] operators see a drop in service cost – one out of four service calls to operators is actually about the battery in the remote control being dead. So with ZigBee in the remote control the cable operator wins twice: reducing service calls and cost. Plus, with ZigBee in every set-top box it allows the subscriber to connect other sensors or applications with the set-top box, enabling incremental services.
For Links, full-fledged adoption of the smart home and its accompanying technologies will progress in the same way that Wi-Fi technology did, with roughly 10 years of cost reductions and cultural breakthroughs before reaching the nearly universal acceptance it enjoys today. Along with progressive reductions in the cost of the technology and success educating the population, however, the achievements of Wi-Fi are largely based in joint industry collaboration around the standard that eventually benefitted all parties involved.
"Cost and culture are the two major constraints," Links says. "Assuming that the cost will decrease with the volume increase, the key will be getting people comfortable with living in a smart home. That means there need to be guarantees that the system is secure, that the system is not infringing on privacy, etc. But to a large extent this is not technology, but a marketing challenge that needs to be resolved in the coming years.
"Also, the industry needs to come together on a set of standards to ensure interoperability and ease of use for the end user. It was the international adoption of 802.11 that truly enabled the eventual market success of Wi-Fi. The industry needs to learn from the Wi-Fi history. The big tech companies need to stop building tech silos designed to fight for market share, and instead realize the more the sectors work together to ensure interoperability, partnership, and customer ease of use, the more successful all tech companies will be," he continues. "With the ZigBee 3.0 unified communication standard in place, smart home applications should not be more costly or complex for the end user than a smartphone. This is when the smart home becomes reality for both vendors and consumers."
 National Cable & Telecommunications Association. "Amendment No. 1 to the Voluntary Agreement for Ongoing Improvement to the Energy Efficiency of Set-Top Boxes." https://www.ncta.com/sites/prod/files/VOLUNTARY-AGREEMENT-ENERGY-EFFICIENCY-OF-SET-TOP-BOXES.pdf