Bringing the three flavors of ZigBee together in the smart home

Cees Links, GreenPeak Technologies

January 11, 2013

Cees Links, GreenPeak TechnologiesJanuary 11, 2013

Editors' Note: A new paradigm for total home control is emerging based on reliable low-power wireless technologies like ZigBee and the Internet. The author explains why entertainment providers need to explore and exploit new markets.

ZigBee is a low-power, low data-rate variant of Wi-Fi, using many of the same networking, security, and interference avoidance technologies and protocols. The Open Smart Home framework combines the three flavors of ZigBee networking into a single architecture, which allows a single ZigBee radio device in the set-top box/gateway to master a complete sense and control home network at a low cost for implementation.

  • ZigBee RF4CE is for very low latency (immediate response) devices like remote controls and other human interface devices;
  • ZigBee PRO provides highly reliable mesh networking, supporting Home Automation and Light Link;
  • ZigBee Green Power supports maintenance-free devices (battery-less, or with battery life exceeding product life time).

Sense and control devices in the smart home require very low power consumption, low cost, and highly reliable and dependable networking capabilities to connect from every location in the home to the set-top box or internet gateway. The set-top box or gateway connects the devices with each other and with the internet, making them reachable both from any place in the home as well as from the outside world using devices such as smart phones.

ZigBee RF4CE
ZigBee RF4CE (Radio Frequency for Consumer Electronics) provides a multi-vendor interoperable solution for consumer electronics featuring a simple, robust and low-cost communication network for two-way wireless connectivity. ZigBee RF4CE is a full member of the ZigBee family and is based on the IEEE 802.15.4 specification. Developed for consumer electronics devices, it was designed for simple, two-way device-to-device control applications that do not require full-featured mesh networking capabilities.

RF4CE has already found its way into TVs, set-top boxes, and remote controls. ZigBee RF4CE offers ease of installation, a high level of reliability over a longer range, a very long battery life, and includes special features to avoid Wi-Fi interference rejection. ZigBee RF4CE offers low memory size requirements, thereby enabling low-cost implementations.

A practical benefit is that the two-way communications capability of RF4CE can support new applications. For example, one interesting application is a “Find Me” button on a TV or set-top box that, once pressed, would cause the remote device to make a sound so the viewer could easily locate it (probably under the couch, where your children left it).

A variety of sophisticated applications offering interactive, two-way viewer participation could be built into the remote control such as televoting and gaming, personal messages and reminders, real-time sports results, stock information, and residential sensor network monitoring. Two way communications enables operators to create new opportunities for advertising revenues via server-initiated commercial push messages on the consumers’ remote control.

The interoperability offered by the ZigBee industry standard allows a remote control to work with more systems in a house and can be used as the basis for home automation. Although the main applications of RF4CE are consumer electronics based, there are no technical restrictions to controling other devices like lights, heating/air-conditioning. Some of these implementation frameworks (Figure 1) are already in the market today. Leveraging the open ZigBee RF4CE standard, the remote will eventually become the dashboard for the home.


Click on image to enlarge.

Figure 1:The new Open Smart Home Framework is a subset of ZigBee that encompasses ZigBee’s three main network layers – ZigBee RF4CE, ZigBee Pro and ZigBee IP

ZigBee PRO
The ZigBee Pro network layer supports Home Automation, Smart Energy, and Light Link application profiles. IEEE 802.15.4 compliant, it offers excellent range and can cover a complete home with multiple floors. It handles dead spots or WiFi interference via mesh networking - the capability where one node can find its way to the Home Control Box via other nodes and is even capable of doing this dynamically. If one route is blocked it will automatically and instantaneously find another route (if one exists) without any user interaction required.

The ZigBee Pro feature set is probably the most popular choice for most ZigBee developed applications. It maximizes all the capabilities of standard ZigBee, plus facilitates ease-of-use and advanced support for larger networks comprised of thousands of devices, which also makes it suitable for industrial applications and building automation.

The wide range of application profiles that ZigBee Pro supports in the home space makes it a complete standard. These applications include Green Power applications.

ZigBee PRO Green Power
The recently approved ZigBee PRO Green Power feature adds support for energy harvesting and battery-free applications as part of the ZigBee 2012 standard. Green Power gives battery-free, energy-harvesting devices the ability to join ZigBee PRO 2012 networks. Without requiring batteries, these self-supporting devices typically generate (harvest) just enough power themselves to communicate a brief command.

For example, a light switch - without a battery - harvests energy from flipping the switch on or off. This energy is captured to send the “on” or “off” command to the network to switch on or off the appropriate light. Hence, the light switch is a self-powered device. As there is no need to run and install power cables, this also makes it easy for the consumer to position and move light switches, without needing the services of an electrician. This also make it easier to add lighting to locations where it is impractical or against the rules to install power lines or permanent light switches such as in historical buildings or for temporary office space.

ZigBee Green Power can be implemented directly one to one – one switch controls one light – or as part of a network where the Green Power switches and the lights can be accessed via the network – and then monitored and controlled by the home’s various switches, by a local remote control or over the internet via a smart phone or smart device. The lights can also be controlled by the home’s central box and its smart programming.

For example, a RF4CE sensor can recognize that someone has just entered a room and send a signal to turn on to the room’s Green Power or ZigBee PRO enabled lamps. When the person leaves the room, that room’s light turns off and the home controller box turns on the lights in the foyer and other rooms as it senses the occupant moving throughout the house.

ZigBee Open Smart Home Framework
Cable companies and service providers worldwide are about to start rolling out the new "Fifth Play" service that combines Zigbee (ZigBee RF4CE, ZigBee Pro, and ZigBee IP) to make the connected home a smart home (Figure 2) .


Click on image to enlarge.

Figure 2: The Smart Home ecosystem will use a standardized technology such as ZigBee to communicate via the set-top box to local controllers as well as smartphones and mobile devices over the web.

In addition to providing the existing Four Plays - TV and entertainment, internet access, phone service (VoIP), and cell phone services - operators will be adding the Fifth Play – smart home services for monitoring energy usage, home health, security, climate control, etc. Companies like Comcast, Time Warner and Verizon are already marketing and installing these types of Fifth Play Smart Home solutions.

This Fifth Play will make the set-top box evolve into the Home Control Box that communicates with the various sensors and devices in the home that then can be controlled and monitored via a local RF4CE remote control or over the net via smart phone applications. Where previously the set-top box was only responsible for distributing content through the home, the Home Control Box makes it possible for consumers to control all kind of applications in their homes and over the internet with smart phone apps.

The truly smart home
The smart home ecosystem will combine a variety of applications with the set-top box, that is, the home control box, acting as a centralized home hub (Figure 3). Not only will the set-top box handle entertainment such as television, movies, gaming, and remote purchasing, it will be the entry point for the home’s phone, internet, telecommunications, and Smart Home services.


Click on image to enlarge.

Figure 3. Targeted for set-top boxes, gateways, and smart home controllers, the GP 690 communication controller can simultaneously support ZigBee RF4CE applications such as remote controls and ZigBee Pro or ZigBee IP Smart Home applications such as security, home care, and energy management. The GP 710 also supports ZigBee GreenPower and includes special hardware features to enable multi-protocol support, minimizing the interrupt load on the set-top box processor and allowing simultaneous RF4CE and other ZigBee protocol operations.

Of course, what we now call the set-top box will evolve as well. It does not need to actually sit on the TV or even be directly connected to the TV via cables. Instead, it can be located anywhere in the home, in a closet or a cabinet, and then use either ZigBee to connect to the various low power, low data sensors, device controllers, and remote controls located throughout the home, or by using WiFi, it will transmit high data rate, high quality video and audio signals to the home’s various entertainment devices. WiFi can also be used to connect the wireless VoIP handsets to the set-top box as well.

The development of smart home services may trigger the emergence of many business models, providing a diverse range of what may become essential components for the smart home ecosystem. These may include:
  • A security breach in the home can immediately send a text message to the home owner and/or a response company.
  • Water leaks or gas leaks can be immediately identified and alerted – saving money and preventing damage.
  • Elderly people can be monitored by their children and medical staff via smart phone and alerts.
  • Medicine consumption can be automatically monitored.
  • Air-conditioning or heaters turn off when windows get opened.
  • Lights are switched off in rooms where are no people.
  • Roof top solar panels can be monitored and controlled to ensure optimal operating efficiency.

The new smart home is on the way
Driven by the cable TV and internet providers, the new paradigm for total home control is enabled by the emergence of reliable low-power wireless technologies like ZigBee, as well as by the need for internet access and entertainment providers to explore and exploit new markets in order to survive. In parallel to this Smart Home Fifth Play evolution, new businesses will emerge to create and feed devices and solutions to the operators.

The big challenge to the smart and connected home has been the plethora of devices already on the market that did not talk or interact with each other because they were not using a standardized communications protocol. With the growing acceptance of ZigBee by leading device makers, operators, and service providers, this impediment is becoming overcome. Another challenge, the technical difficulty and cost of installing and maintaining these systems, will be taken from the home owner and instead be put on the shoulders of the service providers who will also be handling the monitoring and reporting for these in home systems.

These together will create large new opportunities for service providers and equipment makers and move our homes into the smart home era.

Cees Links (pronounced “case”), founder and CEO of GreenPeak Technologies, pioneered the development of access points, home networking routers and hotspot base stations, all widely used today. He holds a masters in applied mathematics and a bachelors in electrical engineering from the Twente University of Technology in Enschede, The Netherlands. Cees started his career at NCR Computers where he was responsible for the development and launch of the world's first wireless LAN product in 1990. In 2004 he started with GreenPeak and has been involved in establishing the IEEE 802.11 standards committee,  the Wi-Fi Alliance, and the IEEE 802.15 standardization committee as the basis for the ZigBee sense and control networking technology and standardization.

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