For smart-home wireless networking, there are numerous technologies competing to become the standard of choice. Wi-Fi and Bluetooth are the most ubiquitous technologies, however both have limitations that make them of limited use for home automation: Wi-Fi consumes a lot of power, and Bluetooth is limited in signal range and number of devices. Furthermore, both technologies are point-to-point, requiring expensive hubs and routers to integrate the networks.
Competing network standards, including Z-Wave, Insteon, Thread, and ZigBee - which are all mesh networks - offer lower power, lower cost, and longer-range solutions. Of the four, Z-Wave has the longest operating range at 300 feet (outdoor) and 80+ feet (indoor). Insteon has the largest number of maximum devices capability at 17.7 million (to ZigBee's 65,000 and Z-Wave's 232). Thread has the fastest data transmission rate at 250 kbps. Z-Wave has better interoperability than ZigBee, but ZigBee has a faster data transmission rate. Thread operates on the busy Wi-Fi standard frequency of 2.4 GHz, while Z-Wave operates at 908 MHz in the US, which has reduced noise and a greater coverage area. ZigBee operates on both 915 MHz and 2.4 GHz frequencies.
Zigbee
Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, and other low-power low-bandwidth needs, designed for small scale projects which need wireless connection. Hence, Zigbee is a low-power, low data rate, and close proximity (i.e., personal area) wireless ad hoc network.
The technology defined by the Zigbee specification is intended to be simpler and less expensive than other wireless personal area networks (WPANs), such as Bluetooth or more general wireless networking such as Wi-Fi. Applications include wireless light switches, home energy monitors, traffic management systems, and other consumer and industrial equipment that requires short-range low-rate wireless data transfer.
Its low power consumption limits transmission distances to 10–100 meters line-of-sight, depending on power output and environmental characteristics. Zigbee devices can transmit data over long distances by passing data through a mesh network of intermediate devices to reach more distant ones. Zigbee is typically used in low data rate applications that require long battery life and secure networking (Zigbee networks are secured by 128 bit symmetric encryption keys.) Zigbee has a defined rate of 250 kbit/s, best suited for intermittent data transmissions from a sensor or input device.
Z-Wave
Z-Wave is a wireless communications protocol used primarily for home automation. It is a mesh network using low-energy radio waves to communicate from appliance to appliance, allowing for wireless control of residential appliances and other devices, such as lighting control, security systems, thermostats, windows, locks, swimming pools and garage door openers. Like other protocols and systems aimed at the home and office automation market, a Z-Wave automation system can be controlled via the Internet from a wireless keyfob, a wall-mounted keypad or through smartphones, tablets or computers, with a Z-Wave gateway or central control device serving as both the hub controller and portal to the outside. It provides interoperability between home control systems of different manufacturers that are a part of its alliance. As of May 2017, there are over 1,700 interoperable Z-Wave products.
Thread
Thread is an open, IPv6-based, low-power, secure and future-proof mesh networking technology for IoT products.The Thread protocol specification is publicly available.
In July 2014, the "Thread Group" alliance was announced, which today is a working group with the companies Nest Labs (a subsidiary of Alphabet/Google), Samsung, ARM Holdings, Qualcomm, NXP Semiconductors/Freescale, Silicon Labs, Big Ass Solutions, Somfy, OSRAM, Tyco International, and the lock company Yale in an attempt to have Thread become the industry standard by providing Thread certification for products.
Thread uses 6LoWPAN, which in turn uses the IEEE 802.15.4 wireless protocol with mesh communication, as does ZigBee and other systems. Thread however is IP-addressable, with cloud access and AES encryption. It currently supports up to 250 devices in one local network mesh.
A BSD licensed open-source implementation of Thread (called "OpenThread") has also been released by Nest.
