ZigBee, Z-Wave and X10, among others, are currently the most widely adopted protocols for connected-home/smart-home/home automation (HA) applications. While appearing to be futuristic and unreachable, HA and its real-life deployments have been around for decades. For example, X10-based devices first hit the shelves of RadioShack and Sears in the U.S. in 1978, and 10 million nodes are estimated to be in US households. Products based on X10 are still the most utilized because the technology is relatively cheap and relies only on a house's existing power lines.
Commutation and networking technologies continue to advance by leaps and bounds, and the emergence and confluence of broadband Internet access, supercharged smartphones and tablets, home networks and controls, and the digitization of entertainment and media services have sparked new interest in ways to tie all the system components together. Technologies, such as ZigBee and Z-Wave, are looking to dethrone X10. While both are based on low data rate, wireless RF, ZigBee has managed to garner more press ink, largely because it is based on an open specification (IEEE 802.15.4) and has “unionized” all stakeholders: chipset providers, solution providers, telcos, alarm-monitoring stations and even large end users.
In response, the proponents of the Z-Wave technology also formed a Z-Wave Alliance, consisting of roughly 60 members that develop conformant products and ensure cross-vendor interoperability. Designed for executing quick and simple tasks, the two protocols only require very little power and are ideal for residential use within closed quarters.
For easier reference and comparison, a snapshot of eight common protocols for HA and controls can be found on the next page.
Home Networking Technologies
ZigBee
ZigBee is a specification for a suite of high-level communication protocols using small, low-power digital radios based on an IEEE 802 standard for personal-area networks. The name refers to the waggle dance of honey bees after their return to the beehive. ZigBee devices are often used in a mesh network to transmit data over longer distances, passing data through intermediate devices to reach more distant ones. Any ZigBee device can be tasked with running the network. ZigBee is targeted at applications that require a low data rate, low cost, long battery life and secured networking. Chip suppliers typically sell integrated radios and microcontrollers, with 60-KB to 256-KB flash memory.
Z-Wave
Z-Wave uses a low-power, wireless radio embedded or retrofitted into home electronics and appliances, such as lighting, access control, entertainment systems, HVAC and refrigerators, remote controls, smoke alarms and intrusion sensors. Z-Wave operates in the sub-GHz frequency range at 900 MHz. Each Z-Wave network may include up to 232 nodes and consists of two sets of nodes: controllers and slave devices. Nodes may be configured to retransmit the message in order to guarantee connectivity in a multipath environment inside a residential house. Each Z-Wave network is identified by a network ID, and each device is further identified by a node ID. Nodes with different network IDs cannot communicate with one another.
X10 is an international open standard for communication among electronics used for HA. An early technology developed by Pico Electronics of Glenrothes in Scotland back in 1975, it primarily uses power line wiring for signaling and control, where the signals involve brief RF bursts representing digital information.
Wi-Fi
HomePlug
HomePlug is a family name for various power line communication (PLC) specifications that support networking over existing electrical wiring. HomePlug specifications were developed by the HomePlug Powerline Alliance. The
HomePNA is a wired, home-networking technology. The HomePNA Alliance develops home-networking specifications for distributing entertainment and triple-play data over existing coax cables and phone wires. HomePNA promoters include AT&T, Cisco Systems, K-Micro, Motorola, Pace, Sigma Designs and Sunrise Telecom. Using frequency-division multiplexing, the technology puts computer data on separate frequencies from the voice signals being carried by the phone line. The latest version, HomePNA 3.1, was developed for entertainment applications, such as IPTV, which require consistent high performance, and is used by service providers for commercial triple-play (video, voice and data) service offerings. HomePNA can be used without interrupting normal voice or fax services, with data rates up to 320 Mbps and capabilities like remote management and diagnostics. Ethernet over coax is also possible, to overcome phone jack location limitations.
LonWorks
Insteon
Insteon is a system for connecting lighting switches, thermostats, motion