In a previous blog, IoT Impact on Wireless, I wrote that wireless network designers have been focusing on the physical coverage area rather than on the number of wireless devices the network is supporting. But this needs to change with the Internet of Things trend driving designers to focus more on capacity and performance.
The support of hundreds of IoT endpoints will require a dense concentration of low-power, low-bandwidth devices. The IEEE 802.15.4 standard, also known as ZigBee, is a mature front runner.
What is ZigBee?
ZigBee is a specification for a group of communication protocols used to create personal area networks (PAN) that support low-power digital radios. ZigBee is based on an IEEE 802.15 standard that specifies transmission distances to 10 to 100 meters line-of-sight. The useful distance depends on power output and environmental characteristics.
Who Defines What?
Only the lower two layers seen in the above graphic are defined by the IEEE standard, while the ZigBee Alliance embraces all four lower layers. The top layer, Application Profiles, can be defined by the ZigBee Alliance or a vendor producing a proprietary solution.
What is the ZigBee Alliance?
Established in 2002, the ZigBee Alliance is an open, non-profit association of members that has created a global ecosystem. Anyone can join, and membership is comprised of businesses, universities, and government agencies from around the world.
Members work together to develop standards that deliver greater freedom and flexibility for a smarter, more sustainable world. The ZigBee Alliance:
Where ZigBee Fits
ZigBee offers a number of solutions for a range of applications including:
The ZigBee Alliance produces a standards overview that covers the range of applications mentioned above.
ZigBee is often mentioned in two areas: building and home automation. I found that ZigBee has been applied to a manufacturing line, in store (retail) communications, and alarm systems. ZigBee is also in use with cable service remote controllers. The business applications will eventually expand beyond the home/consumer applications, so enterprise IT should acquaint themselves with ZigBee now in addition to Wi-Fi and Bluetooth.
Comparing Wireless Choices
There are three common choices for connecting to wireless endpoints over short distances (generally considered 100 meters or less): Wi-Fi, ZigBee, and Bluetooth. The choice for IoT has to be able to support many endpoints in a limited area. The data produced by IoT endpoints is modest, so the bandwidth required is also modest (kbps not mbps). The number of endpoints ZigBee can support is far greater than Wi-Fi and Bluetooth. Neither of these was designed for high-density, large endpoint populations.
Comparing Wireless Solutions
Wi-Fi is best suited for desktops, laptops, tablets, and phones that require high data rates. Bluetooth was designed mainly to service on a desk connecting a wireless keyboard, mouse, printer, or headset. When the supported population and area coverage are both large, then ZigBee becomes the obvious solution.
A Different Endpoint Design
A major benefit to ZigBee is its design to reduce power consumption, which can thereby vastly extend battery life. Tobin Richardson, chairman and CEO of the ZigBee Alliance, made this comment to me at the IoT summit that took place at the end of October in Washington, D.C. He also pointed out that IoT endpoints will probably be installed to operate for 10 to 20 years.
Tobin also said IoT endpoints must be very reliable so that they require little or no maintenance. He foresees that the cost of maintaining IoT endpoints must be very low in order to be affordable. This means there should be very little labor expended for their support. The endpoints may only be visited every few years. This is significantly different than many IT endpoints today that may be obsoleted every one to three years.
Network Topologies
Another advantage of ZigBee is that endpoints can act as relay sites for other endpoints. Since ZigBee is designed for line-of-site transmission, not all endpoints will be capable of connecting to a ZigBee router that then connects to a remote system or cloud service. ZigBee network devices can be a:
IT or OT for IoT?
When researching the applications of ZigBee for IoT, it became apparent that IoT sensors and the data they collect is for business operations (OT), not IT. There are installations where the collected data is processed in a cloud service and the results are communicated to operations personnel.
When this is done, IT has no useful function other than to help OT with some technology decisions, but IT is not involved with the business decisions generated by IoT data. Further, when changes have to be made to the IoT control devices, the changes are an OT decision. So although IoT appears to be an IT responsibility, I predict that a number of IoT applications and endpoints will not be the responsibility of IT, but operated disconnected and independent from IT.
Do you agree with my prediction or do you foresee a different future? Share your thoughts in the comment section below.
