the many available technology choices, the Z-Wave protocol stands out as the
only one offering all desired attributes. Other protocols have specific
advantages, but these come at the expense of other considerations – Wi-Fi, for
example, has superb bandwidth, more than is needed for command and control
applications, but this comes with high power consumption cost, making Wi-Fi
based battery-powered devices unrealistic. Bluetooth and Bluetooth LE both
offer excellent power profiles and bandwidth, but fall short when it comes to
HAN coverage and support for enough devices in a network for complete home
control solutions. ZigBee technology comes the closest to providing the right
mix of power, bandwidth, HAN coverage, and ease of installation; however it has
failed to provide a rich ecosystem of interoperable products from multiple
manufacturers. Z-Wave is the one protocol that offers the right balance of
bandwidth, range, power consumption, cost, and product-level interoperability
across multiple manufacturers, making it the best overall choice for the vast
majority of smart device applications.
Z-Wave's advantages start with the radio frequencies used. The specific frequency varies slightly based on international region, but all Z-Wave communication takes place in the 900 MHz band. Basic physics plays a role – at a given power output level, frequency governs battery life and is regulated by the government. As frequency goes up, so does bandwidth, but range, object penetration, and battery life go down.
Z-Wave uses the 900 MHz band as that has been found to have the optimum balance of power consumption, bandwidth, and range. The 2.4 GHz band used by almost all alternative technologies in this application space has the advantage of being a global frequency, however, this comes with the cost of higher than needed bandwidth and power consumption, as well as a very congested spectrum. Since almost all smart devices have to be localized in their form factors and safety approvals, using a globally approved frequency as opposed to a specific frequency selected in firmware is of minimal, if any, advantage.
The Z-Wave Physical and Media Access (MAC/Phy) layers are defined by an International Telegraphic Union standard, ITU-T G.9959. This robust, field-tested international standard is in the public domain and is available free without licensing fees.