Comparision on Zigbee, Z-Wave, and Z-Wave Long range.

 This article tries to discuss differences of Zigbee, Z-Wave, and Z-Wave Long range on network Topology, radio coverage, and number of nodes supported in single network, security, power consumption, interoperability, logistics, prone to interference, chip vendor...

1. Network topology, radio coverage, and number of nodes supported in single network

Both Zigbee and Z-wave support mesh network but Z-Wave Long Range only support star network. 

For Zigbee, radio coverage of single hop would be about 50-250 meters in line-of-sight test and it's usually not recommended to have more than 5 hops in Zigbee mesh network. In this way, the radio coverage in line-of-sight test would be able to reach 1.5KM. Since Zigbee runs on 2.4GHz band which is prone to interference by WiFi, BLE, or other 2.4GHz equipment so the radio coverage might be smaller. In theory, a single Zigbee network can have max 65535 nodes.

For Z-Wave, radio coverage of single hop in would be about 30-100 meters in line-of-sight test and Z-Wave mesh supports max 4 hops. In this way, the radio coverage in line-of-sight test would be able to cover 500 meters. However, a single Z-wave mesh network only supports max 232 nodes.

For Z-Wave Long Range, it only supports star network, but it can have radio coverage upto1600m in line-of-sight and can support max 4000 nodes in a single network. It is amazing on radio coverage but currently only support US market.

2. Security

Basically, Zigbee and Z-wave use AES-128 to do network and application packet encryption. Different key exchange process in Zigbee/Z-wave provides different level of security.

Previous Zigbee HA profile 1.2 supports well known TC link key to exchange single network key for all joined device and this is less secure. With latest Zigbee 3.0, it enable Install code/Variable TC Link Key with variable network key for different joined device and it provides best security for now.

Z-wave provides S0, S2 non-Auth, S2 auth, and S2 Access. For backward compatibility, Z-wave protocol has to support S0 but it's recommended to use S2 auth at least for secure connection.

Z-Wave Long Range only supports S2 auth and S2 Access which provide best security for now.

3. Power consumption

Zigbee and Z-Wave have developed for more than 10 years so there are different chip generations for two protocols.

For Zigbee, previous generation (such as Texas Instruments CC2530 or Silicon Labs EM35x) consumes higher power (battery power can last about 2-5 years depending on different applications). New generation (such as Texas Instruments CC2652 or Silicon Labs EFR32) improves lots on power consumption and battery power (CR2032 also applicable) can extended to about 4-10 years depending on different applications.

For Z-wave, previous generation (500 series) also consumes higher power and battery power can last about 2-5 years depending on different applications. New generation (700 series) also improves power consumption and battery power (CR2032 also applicable) can extended to about 4-10 years depending on different applications.

Z-Wave LR offers up to 10-year battery life on a single coin-cell battery by leveraging dynamic power control. This new feature enables the Z-Wave Long Range device to automatically adjust and optimize the radio output power at every transmission.

4. Interoperability, logistics, and Prone to interference

Before Zigbee 3.0, there are different Zigbee profiles and products of different profiles cannot interoperate to each other. Zigbee 3.0 unifies this for better interoperability. Current Zigbee products run on unified 2.4G Hz frequency band so it's easier for logistics. However, there are lots other 2.4G Hz protocol such as WiFi and BLE or other 2.4G Hz equipment so Zigbee is prone to interference.

Z-wave is always an unified protocol (products need to be certified by Z-wave alliance before releasing to market) and providea best backward compatibility for different protocol generation. Since Z-wave works on sub GHz ISM band so different region needs to use different frequency band. This usually causes complex logistics if you support world-wide products but sub GHz ISM band would avoid prone to interference on 2.4G Hz interference.

Z-Wave Long Range and Z-Wave are also designed to co-exist on the same network, with LR network nodes reserved for new or existing Z-Wave mesh network devices to preserve both backwards and forwards compatibility and sustain interoperability between certified Z-Wave devices.

5. Chip vendor and chip/module cost

For Zigbee, there are different chip and stack vendors such as Silicon Labs, Texas Instruments, NXP,etc. Due to open competition, Zigbee chip is usually cheaper.

For Z-Wave and Z-Wave Long Range, Silicon Labs is the only chip/stack vendor. Because of no competition on chip vendor, Z-Wave chip/module price is usually higher in comparison to Zigbee chip/module.

To conclude, there is no superior or best protocol for smart home for now. Even with most popular Zigbee and Z-wave protocol, they have advantage and disadvantage for your own choice. Later in 2021, OpenThread and CHIP (connected home over ip) are trying to unify everything. OpenThread is still based on 2.4G Hz 802.15.4 protocol and has similar advantage and disadvantage with Zigbee so I don't think it might unify or dominate the market. From my personal point of view, smart home would be still  a versatile and open market for a long while.