Wireless Protocols: The Basics

Part 3 of 6 of my Smart Home Series.

Smart devices must have a way to communicate with themselves, their hubs, or a smart phone. It is this ability to communicate that make the devices ‘smart’ after all. In today’s market, there are three main technologies used: Z-Wave, Wi-Fi and ZigBee. All three are what we technically term as wireless protocols and are how devices communicate which each other.

Frequency

​The three protocols all transmit data through radio waves and they each operate on specific radio frequency bands. The Wi-Fi protocol runs on 2.4 GHz or 5 GHz frequency band. ZigBee also runs on 2.4 GHz frequency band. Z-Wave, on the other hand, runs on a lower 908.42 MHz frequency band. Generally, the lower the frequency, the better and further the radio waves travel. Interferences such as concrete walls or furniture in the house will not affect lower frequency radio waves as much as higher frequency radio waves. However, the lower the frequency, the lower the data transfer rate. All these factors may affect the effectiveness of smart devices depending on which protocol it runs on.

Branding​

A lesser known fact is that these three protocols are actually brands themselves. Wi-Fi is a trademark of the non-profit Wi-Fi Alliance. The Z-Wave protocol is maintained by the Z-Wave Alliance and the ZigBee protocol is maintained by (you guessed it) the ZigBee Alliance. Both Wi-Fi and ZigBee allow OEMs to use their protocols to manufacture products, which makes for cheaper devices on the market. Z-Wave, on the other hand, is a little more exclusive in this aspect, which makes Z-Wave devices relatively more costly. It also follows that Z-Wave devices are not as plentiful in the market as the other two technologies.

Mesh network​

A mesh network basically means that data transmission can be relayed from mesh device (e.g. a router) to mesh device. The more routers you have, the more relay points there are. This contributes to fault-tolerance in the network and allows for transmission to go across a far greater distance. In conventional networks, or what we technically term as star/tree network, transmission of data is only from one central router. This single line of transmission will not be able to reach far, though its range can be extended with a repeater. However, a repeater is not the same as a mesh relay point. In fact, it is more disadvantageous as a repeater actually halves the transmission rate while the mesh relay point carries the full transmission load. Mesh networks are, thus, very powerful and desirable.​

Wi-Fi, Z-Wave and ZigBee can all operate on a mesh network with specific routers used.

Security​

Z-Wave and ZigBee uses AES 128 encryption standard for their security and simply put, it is very well protected. Wi-Fi security protocols includes WEP, WPA and WPA2, which are unfortunately not as well protected.

Power consumption​

Wi-Fi devices actually consumes the most electrical power. Both Z-Wave and ZigBee are very low-power and consume only a fraction of the power required by Wi-Fi.

End of Part 3 of my Smart Home Series.