Articles and whitepapers

ZigBee Technology - The Home of the Future (5/9/2005)

By Bob Heile, ZigBee Alliance

We are on the cusp of seeing a home network that will allow you to control almost every aspect of comfort, security and utility within your residence, thanks to a rapidly-growing wireless technology called ZigBee. Every room will be at an optimal temperature all year long. Your utilities will 'sense' the most energy-efficient time of day to run. Your smoke alarm may go off in your basement, but you will be awakened by the one mounted over your bed when it is wirelessly triggered to sound. While some of this is already a reality, to a limited degree, with the help of wireless technologies, ZigBee will soon automate the entire home; unidirectional IR remote controls will become obsolete and homes of the future will run more efficiently, more safely and more economically.

ZigBee is a global standard for wireless connectivity, which is particularly useful for residential control because of its reliability, low cost, long battery life and easy deployment. ZigBee's use of 'smart sensors' and mesh networking help provide greater control of almost every aspect of the home, including a variety of remote control applications such as keyless entry, garage door openers and remote control applications.

In addition to residential control, ZigBee technology is well-suited to a wide range of applications including industrial, medical and monitoring. Indeed any application that requires interoperability and/or the RF performance characteristics of the IEEE 802.15.4 standard would benefit from a ZigBee solution.

The ZigBee standard

While numerous wireless standards exist for high-speed data applications, none of these address the unique needs of remote monitoring and control for sensory network applications in the way that ZigBee does. The ZigBee standard is built on the IEEE 802.15.4 global standard. The ZigBee stack, which sits on top of IEEE 802.15.4, adds an application services layer, security layer and the mesh network layer to create the ZigBee standard. The combination delivers low complexity, inherent reliability, long battery life and the ability for networks to form autonomously and maintain themselves without operator intervention.

How ZigBee works

While ZigBee supports a variety of network topologies, including star, mesh and cluster networks, its mesh network design is a fundamental and differentiating attribute. Enhancing the overall network reliability, mesh networking topology increases the number of pathways information can travel. If a device encounters a closed path, it automatically seeks out another path to execute the action. ZigBee devices will always know who they need to speak to, what they need to tell one another, no matter how many devices you have in your home.

ZigBee's addressing scheme is capable of supporting over 64,000 nodes per 'network coordinator', and multiple network coordinators can be linked together to support extremely large networks. The logical size of a ZigBee network ultimately depends on which frequency band is selected, how often each device on the network needs to communicate and how much data loss or retransmissions can be tolerated by the application. Additionally, ZigBee's capabilities allow for very low average power consumption because the duty cycle of battery-powered nodes within a ZigBee network are designed to be very low.

The ZigBee Alliance

The technology is being driven by the ZigBee Alliance, an association of companies working together to enable wirelessly networked monitoring and control products based on an open global standard. It includes a rapidly growing list of over 175 industry leaders from around the world including semiconductor manufacturers, wireless IP providers, OEMs and end users. The collaborative nature of the ZigBee Alliance has helped to foster its success. Recently, the Alliance made the specification publicly available to universities, research institutions and software developers to review the technical details of the specification in its entirety. This has helped individuals and organisations gain a greater understanding of the value of ZigBee to their wireless networking efforts. The opportunity to access and view the ZigBee specification directly from the Web transcends geographic hurdles in educating people on the benefits of ZigBee-based wireless networks.

By creating a standards-based wireless networking solution, the ZigBee Alliance ensures that product solutions are vendor independent. Companies will be able to easily and cost-effectively include ZigBee-compliant wireless networking capabilities into their products through the introduction of small, low-power, wireless RF modules. The availability of standards-based hardware and software solutions dramatically reduces the cost and complexity of integrating embedded RF into the typical product design. Vendors will provide software toolkits, including profile templates, to enable OEMs and end users to efficiently create application layer solutions at low cost, and reduce time to market.

Summary

ZigBee was designed to overcome barriers to wireless adoption as it can be added to existing products. Consumers and/or installers simply connect a ZigBee-enabled device to the home environment and through a simple method of association, are able to add a new device to the network. Homeowners will be able to buy off-the-shelf products and be assured that they will work together in their networked environment. For installers, ZigBee supports a suite of enhanced functionality and customisation. As a standards-based wireless technology, ZigBee RF modules will be manufactured into multiple new product applications in 2005. Indeed some manufacturers have already included 'extension connectors' into their present day products for an upgrade path to emerging wireless technologies such as ZigBee.

Bob Heile is the chairman of the ZigBee Alliance. The ZigBee Alliance will hold its inaugural ZigBee Developers' Conference on October 3rd - 6th to provide developers with a hands-on opportunity to evaluate ZigBee technology into products and attend workshops on four ZigBee-compliant platforms. For more information/registration, or to download the ZigBee specification in a read-only format, free of charge, go to:

www.zigbee.org