Wireless control in the Lighting, HVAC and building automation market is gathering momentum. Primary wireless technologies used in building control systems include Bluetooth, Wi-Fi, ZigBee and Proprietary technologies. Vendors eyeing the potential billion-dollar Internet of Things (IoT) market are pushing different technologies to establish a clear wireless standard. But which technology provides the best solution for commercial and industrial smart building applications? More importantly, how do you define best? Here is a quick primer on key wireless technologies:
ZigBee
ZigBee is a wireless communication and application protocol managed by the ZigBee Alliance. Based on IEEE 802.15.4 standard, ZigBee uses the direct sequence spread spectrum (DSSS) modulation. It is an open, global standard with support from over 400 companies worldwide. ZigBee uses small, low-power digital radios to form a self-organizing, self-healing “mesh network”. The technology is suitable for applications that require low data rate and long battery life. Relative to Wi-Fi and Bluetooth, ZigBee uses very little power, is very cost effective and ideal for sensor based applications. ZigBee by far has the largest penetration in the building automation, energy management/efficiency and industrial control market. With ZigBee 3.0 release that unifies all profiles into a single universal standard, the technology looks more promising than ever.
Bluetooth
Created by Swedish technology company Ericsson, Bluetooth is a wireless personal area network (PAN) technology to exchange data over short distances. Based on IEEE 802.15.1 standard, Bluetooth uses frequency hopping spread spectrum (FHSS) technique. Bluetooth operates in the unlicensed industrial, scientific and medical (ISM) band at 2.4 to 2.485 GHz. The 2.4 GHz ISM band is available and unlicensed in most countries. The development and technology licensing is managed by Bluetooth special interest group (SIG). Bluetooth was designed to stream data and allow end users to share voice, music, photos and other information between paired devices using a wireless link. The drawback of Bluetooth technology stems from high power consumption (EDR and HS version) and short range under 30 feet. Although the latest 4.0 release called Bluetooth low energy (BLE) is more power efficient and targeted at newer applications, Bluetooth has struggled to gain a foothold beyond peripherals, audio, fitness and health care segment.
WI-FI
Wireless local area network (WLAN) or Wi-Fi has become the standard technology for wireless networking of computers and digital devices. The term Wi-Fi refers to the IEEE 802.11 set of standards for wireless networks that use radio technology to transmit data over short distances using direct sequence spread spectrum (DSSS) or orthogonal frequency-division multiplexing (OFDM) scheme for newer versions. Wi-Fi systems transmit data in the unlicensed 2.4GHz or 5 GHz ISM radio bands. The network’s central point is the access point called gateway or router that transmits data. Typically, the range of a Wi-Fi access point is about 300 feet outdoors and 150 feet indoors. The limitation of this technology includes high power consumption, high cost of implementation, interference from other wireless devices, and incompatibility with older Wi-Fi versions (802.11b/g/n/ac).
Proprietary Wireless
By virtue of being a proprietary technology, nothing much needs to be said. Proprietary technologies hamper interoperability and work against the fundamental idea of open standards – driving costs down through innovation. There will be few niche applications that perhaps require a proprietary wireless but for most applications, this is not a viable choice. Most of the variants are a customized version of ZigBee based on the IEEE 802.15.4 standard with a proprietary application layer and do not offer any value over standard ZigBee solution.
The following table provides a summary of primary wireless technologies used in wireless building controls. It is clear from this comparison that each technology offers value to a specific vertical. However it is hard to beat the value of ZigBee in terms of scalability, cost, performance and reliability for building automation and control market.
