The comparison between WIFI and Zigbee

Jul 08,2021

The basic differences between Zigbee and Wifi 


Zigbee protocol, which was established in 2003, is an open standard communication protocol based on IEEE802.15.4. It also manages other low-rate networks such as 6LoWPAN and Thread. The name of "bee" is inspired by the zig-zag dance of bees as they pass messages up close. As a result, Zigbee is considered to be a low-power, low-bit-rate, 2.4 ghz band short-range protocol for efficient communication between "Mesh" devices.


With a top speed of 250kbps, Zigbee is a puny compared to Wi-Fi, which is clearly not the reason for its popularity. As shown in figure, Zigbee device object (ZDO) is located at a higher application layer than the physical (PHY) layer running 2.4 GHz (and 915 Mhz) radio. This design is suitable for Zigbee devices with longer battery life. As a result, Zigbee devices consume several orders of magnitude less power than Wi-Fi radios running on a similar 2.4 GHz spectrum.


Wi-Fi, founded in 1997, is a wireless network protocol based on the IEEE 802.11 standard. It has higher bandwidth, ranging from 32 Mbps (802.11 a/b/g) to 700 Mbps (802.11 ax) , also known as Wi-Fi 6. Originally used to connect computers and network devices in local or wide area networks, Wi-Fi has rapidly evolved to support the communication of smart phones, smart speakers, smart televisions and home security cameras other smart consumer appliances. WI-FI standards are maintained worldwide by the WI-FI Alliance to ensure compatibility and interoperability of WI-FI products.


Unlike Zigbee, which uses a "Hub" device to join a Zigbee node, Wi-Fi is managed using a wireless router, WI-FI device, or portable hotspot. Also unlike Zigbee, the Wi-Fi design consumes more battery power, and most Wi-Fi compatible commercial devices have a Wi-Fi chip that communicates with a wireless access point, a Wi-Fi router.


The technical differences between Wi-Fi and Zigbee products are much more detailed. This explains the main advantages and disadvantages of each technology over others, and why each is suitable for different types of smart home applications.


The Pros of WIFI 


  1. Cost


  Zigbee smart devices are known to be more expensive than Wi-Fi devices designed for the same purpose. This is because Wi-Fi devices have been in the market for a long time. Whilst, more device manufacturers may support Wi-Fi devices than Zigbee for a given application. This may limit your options. However, the cost of Zigbee is reduced because you do not need to purchase a separate repeater. Each Zigbee device acts as an extended repeater.


  2. Range


  The challenge with most Zigbee devices is that they work better over short distances due to their short-wave physical characteristics. In contrast, remote Wi-Fi can support distances of up to 100 meters. This means that they are less susceptible to signal interference compared to Zigbee devices. In any case, Zigbee signals are weaker and may increase distortion and signal deterioration if there are too many Zigbee devices within a short distance. Modern Wi-Fi networks overcome this obstacle by improving the quality of service, making them less susceptible to signal problems.


  3. Device Integration


  Integrating Wi-Fi connectivity on IoT devices is easier than with Zigbee. Wi-Fi chips are assembled on almost all IoT boards and can help connect to any wireless access point.


  4. Security


  Compared to Zigbee, Wi-Fi is more secure. Since Zigbee is an open standard technology, the compatibility between Zigbee devices from different vendors is better than Wi-Fi. On the other hand, all Zigbee devices speak the same common language, so applications from different vendors are compatible with each other, which poses a greater security risk.


  5. Consumer IoT applications


  Wi-Fi offers higher bandwidth and is definitely better suited for consumer IoT applications such as smart speakers, smart bedside tables, smart home security cameras and other everyday activities. You can't even use Zigbee to send email, so it's not suitable for any consumer IoT applications that may require constant user interaction. They are really better suited for smart home automation.



The Pros of Zigbee


  1. Backward and forward compatibility


  According to the Zigbee Alliance, a key highlight of Zigbee product certification is that they are designed to be compatible with older and future versions of Zigbee. The latest ZigBee 3.0 devices allow for backward compatibility, while older Zigbee devices can join the Zigbee 3.0 network based on allowed security policies and through over-the-air updates. With Zigbee, if you already have smart home devices deployed in your network, you can be sure that they will be compatible with the new Zigbee nodes.


  Wi-Fi certainly doesn't exactly offer this advantage. While you can use Wi-Fi 6 with previous standards, there is no forward compatibility for devices designed for earlier versions of Wi-Fi.


  2. Fault tolerance


  Zigbee and Wi-Fi both follow different network topologies. zigbee is arranged around a grid, with each node talking not only to a "coordinator" but also to other nodes, thus increasing fault tolerance. If one of the nodes is disturbed/damaged, it does not affect the rest of the network. There is a reason why industrial automation (IIoT) uses networks like Zigbee and Z-wave. This benefits is also suitbale to smart homes.


  Wi-Fi networks typically use a "star" topology of routers and repeaters (although a Wi-Fi grid structure is possible). If a Wi-Fi repeater in the network is damaged, the failure is passed to all end-node devices connected to that repeater.


  3. Extended coverage


  Zigbee allows each Zigbee node to act as a repeater instead of manually adding repeaters as in a Wi-Fi network. As long as the ZDO is powered on, it can act as a relay point to transmit signals to the end nodes. Therefore, the more Zigbee devices you buy, the wider the coverage (although you should worry that too many Zigbee nodes will cause signal interruptions).


  4. No need to enter a password every time


  When using a Wi-Fi network, you need to enter a password every time you add a new device.


  The Zigbee protocol, on the other hand, supports a feature called "device discovery service" because all Zigbee endpoints have a unique hexadecimal device ID that will automatically discover and connect to client nodes in the network, eliminating the need to manually enter a password.


  5. Reduce dependence on the cloud


  Zigbee endpoint node devices are less dependent on cloud updates than Wi-Fi compatible devices. While they do provide over-the-air (OTA) update services, all Zigbee devices run on their own grid. In this way, they are vendor independent. Therefore, if a device manufacturer stops supporting one or more features, it will not affect the field operations of existing deployments.


  6. Low-power devices


  As mentioned above, Zigbee devices have been designed to operate in low-power mode. This provides more standby time and more continuous operation. Longer battery life comes at the cost of bit rate, and with a maximum speed of 250 bits/sec, you can only use Zigbee for home automation.


  7. Types of devices supported


  Zigbee is becoming a well-liked choice for lighting management, energy management, HVAC control, security surveillance, environmental monitoring and commercial buildings. Some common applications for Zigbee include wireless and multi-functional gateways, smart switches, dimmers, LED bulbs (such as Philip Hue lights) and other multi-purpose components.



The advantage of WIFI compared with Zigbee


  Wi-Fi vs. Zigbee: Which is better for the smart home?


  In the above comparison of Zigbee and Wi-Fi, we explored the advantages and disadvantages of each of them. If you want greater autonomy and freedom from vendor control, Zigbee will gain more support, but it's too early to declare Zigbee the winner of our contest. Both network protocols have their acceptable standards for smart home use. If you're just starting to build a smart home, it's best to use Wi-Fi compatible devices with Alexa, Google Home and other speakers.


  However, if you want to make some changes to your house with smart lights, curtains, switches, thermostats and other building automation activities, Zigbee-compatible devices and smart home hubs will be better suit your needs.


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