BLE, BT, and BT Mesh: How Bluetooth and Zigbee Work

The Zigbee and Bluetooth wireless protocols are widely used for communication in Internet of Things (IoT) applications, and there are some important differences between them, which we will look at in this article.

Each protocol has its strengths, which guide the choice of solution.

In certain situations, one protocol will be better suited than the other, although sometimes the right solution is to implement them together to get the advantages of both.

To better understand these IoT protocol options, let's look at the advantages and limitations of Zigbee and then at the three versions of Bluetooth: Classic, BLE, and BT Mesh.

This analysis will help you choose the ideal protocol for your IoT application, whether it's a smart city, industrial IoT, or home automation.

What do BLE and BT mean?

BT is short for Bluetooth, and BLE is Bluetooth Low Energy, the version of Bluetooth designed to use very little power. Both are part of the same standard, but they are different radios: Bluetooth Classic is the one used for audio, in headphones, speakers, and cars, while BLE is found in sensors, locks, and the setup of many home automation devices.

According to the Bluetooth SIG, Classic, also called BR/EDR, is used mainly to stream audio, and LE was designed to operate on very little power. When both acronyms appear together on a product's spec sheet (as in "BT/BLE"), the product supports both modes.

What does Wi-Fi + BLE mean?

It's a device with two radios: Wi-Fi connects it to the router and the internet, and BLE is generally used for setup from the phone, which sends the Wi-Fi network name and password to the device over Bluetooth. The chipmaker Espressif, for example, calls this feature BluFi, and many Matter devices are also set up over the phone's BLE.

Zigbee technology

Zigbee is an open, global standard that works as a mesh network. Fully wireless, it offers low power consumption and narrow bandwidth, for better range.

The protocol is maintained and developed by the Connectivity Standards Alliance (CSA), the consortium of companies that used to be called the Zigbee Alliance and adopted its current name in May 2021.

Zigbee can carry data over longer distances thanks to its mesh topology, which passes information through intermediate nodes: they talk to the nodes farthest from the gateway and act as signal repeaters.

In other words, messages "hop" through intermediate nodes on the way to their destination.

Zigbee's 2.4 GHz frequency band can be used worldwide and is widely adopted. According to the CSA, more than 1 billion Zigbee devices have already been installed around the world.

Advantages of the Zigbee protocol

With Zigbee, you can build small, medium, and large networks, larger than the range of any point-to-point radio, thanks to the mesh topology.

The Zigbee mesh configures and reconfigures itself automatically, even if some nodes are turned off or removed (a process called self-healing).

Zigbee documentation is widely available and covers many applications.

Routing tables, address resolution, and communication security are built into the protocol, which saves engineering time and shortens time to market for products.

Zigbee supports several network topologies, such as point-to-point, point-to-multipoint, star, and mesh, and allows more than 65,000 nodes per network.

Limitations of the Zigbee protocol

As in most mesh networks, the nodes that repeat messages need a constant power supply. Devices that sleep to extend battery life, such as sensors and locks, take part in the network but don't repeat the signal.

Zigbee doesn't use IP addressing, so a gateway is required to connect the mesh network to the IP network and to cloud servers.

Since most phones, tablets, and computers don't have a Zigbee chip, gateways are needed to communicate with them.

Although the idea is for all products, from different manufacturers, to talk to each other, in practice, because there are different versions of Zigbee as well as proprietary command classes, the gateway needs to have the devices configured in its application to be compatible with them.

Some of these limitations are the target of Zigbee 4.0, announced by the CSA in November 2025 and compatible with Zigbee 3.0. It strengthens security and brings Zigbee Direct, which uses the phone's Bluetooth Low Energy to set up and control devices without going through the hub. At the same time, the CSA launched the Suzi brand, for Zigbee in the sub-1 GHz bands (800 MHz in Europe and 900 MHz in North America), which have longer range.

Where Zigbee is used

Home automation was the birthplace of Zigbee, but commercial and industrial uses are just as important, including applications in energy efficiency, medical systems, factory automation, and street lighting.

Urban lighting is a great example of a growing trend in mesh networks, and Zigbee is well suited to it because it can manage a large number of devices.

Agribusiness also takes advantage of mesh technology. One example is the management of irrigation devices.

Bluetooth technology

Bluetooth is a wireless networking protocol designed for short-range communication. It was created to replace the cables between computers, smartphones, headphones, keyboards, and mice.

Like Wi-Fi and Zigbee, it operates in the 2.4 GHz frequency band, which is license-free and widely used around the world.

The Bluetooth standard is developed and managed by the Bluetooth Special Interest Group (SIG), which coordinates compatibility among manufacturers.

The Bluetooth brand covers different protocols. Although they are interoperable, it's easier to study them separately.

According to the Bluetooth SIG, production of Bluetooth devices was expected to exceed 5.3 billion units in 2025.

Bluetooth Classic

Bluetooth Classic was designed to transmit data at a high bandwidth of 2.1 Mbps, over short distances, in applications where battery life is not a concern.

It's an excellent solution for audio devices, which need bandwidth and are plugged in all the time or can be easily recharged.

Bluetooth Classic chips are found in headphones, keyboards, mice, printers, and thousands of peripherals that connect to a computer, a car's infotainment system, or a smartphone.

Bluetooth Classic uses an architecture in which a main device (the master) communicates with up to seven active devices at the same time, forming a small local network called a piconet.

Advantages of Bluetooth Classic

The high data rate of Bluetooth Classic is its strong point. It's the ideal protocol for audio streaming, and it's easy to pair and start receiving and transmitting data.

Classic is a mature protocol, its documentation is widely available, and the chip is found in virtually every current smartphone and computer.

Limitations of Bluetooth Classic

Its bandwidth also means it consumes a lot of power. The protocol was designed for devices that are easily recharged, which makes it unsuitable for many IoT applications.

Networks are small, since the protocol was designed to replace short cables, not to build networks that connect hundreds of devices.

Bluetooth Low Energy (BLE)

Bluetooth Low Energy, as the name says, solves the Bluetooth Classic problem by allowing low power consumption.

On the other hand, it doesn't offer much bandwidth, so it's used in situations that don't require a high data flow, such as home automation.

BLE is found in sensors, smart locks, and thousands of other battery-powered devices.

BLE implements a client-server architecture that lets the hardware use only the resources it needs, saving battery and bandwidth.

BLE networks can, in theory, contain a large number of devices, although bandwidth and range limit the size of a single network.

Advantages of BLE

The main advantage is that it doesn't use much power. Devices can run on coin cell batteries for long periods, which makes Bluetooth LE the ideal choice when it comes to energy efficiency.

The protocol brings other advantages, such as simpler hardware, which allows for a lower-cost chip.

The client-server model makes communications easy to implement, reducing engineering and development time.

The protocol is widely accepted and implemented in billions of devices around the world.

Limitations of BLE

BLE is a point-to-point protocol. Therefore, nodes can't communicate beyond their individual range.

This limits the physical size of networks to the range of each device. The Bluetooth SIG points out that this range varies widely, from less than one meter to more than one kilometer, depending on the radio and the antenna; indoors, walls, glass, and metal shorten the distance considerably. It works well in offices and small homes, but it isn't suitable for larger applications.

IP addressing is not implemented, so a gateway is required to communicate with cloud servers.

Some BLE applications are designed to use the smartphone as a gateway, but this only works when the smartphone is on, nearby, and connected to the internet.

BLE has much lower bandwidth than Bluetooth Classic and can't carry video. For many years, it didn't carry audio either. That changed with LE Audio, whose specifications the Bluetooth SIG completed in 2022: it brings audio to BLE with the LC3 codec, which offers high quality at low power, and with Auracast, which streams the same audio to several headphones or speakers at the same time.

Bluetooth Mesh

Bluetooth Mesh (BT Mesh, also called BLE Mesh because it runs on top of BLE) was launched by the Bluetooth SIG in July 2017. It extends point-to-point BLE to create mesh networks, in which nodes can act as signal repeaters.

BT Mesh is similar to Zigbee in function and architecture, with a few differences.

A BT Mesh network can, in theory, have more than 32,000 nodes, but, as with other protocols, bandwidth and physical space limitations keep networks much smaller than that.

Advantages of Bluetooth Mesh

Mesh networks aren't limited to the individual range of each node. Instead, each node can relay and route messages to other destinations, forming larger networks.

Since Bluetooth Mesh is based on BLE, it inherits the protocol's advantages, such as low power consumption, security, and comprehensive documentation.

BT Mesh networks form and heal themselves, much like Zigbee, and their performance is exceptional.

Limitations of Bluetooth Mesh

Bluetooth Mesh keeps evolving. Version 1.1, from 2023, introduced directed forwarding: only the nodes on the path to the destination relay the message, which reduces traffic and makes larger networks easier to build.

In home automation, however, it's found in fewer gateways and devices than Zigbee, so check compatibility between devices before choosing.

Any device that does routing must run on AC power, because, just like Zigbee nodes, nodes that act as signal repeaters can't sleep.

They don't use IP addressing, so interactions with the internet and cloud servers have to go through the gateway.

Where BT Mesh is used

Bluetooth Mesh was initially designed with the lighting market in mind. Since router nodes need continuous power, lighting is an excellent application, as most of these devices are connected to AC power full time.

Zigbee or BLE: what's the difference?

Both use little power and the 2.4 GHz band, but the network is different: Zigbee forms a mesh between devices and needs a gateway to reach the phone and the internet, while BLE connects each device directly to the phone or to a gateway, point to point. In a home with many switches and sensors, the Zigbee mesh has the edge; for a standalone device, such as a lock used close to the phone, BLE does the job without a hub.

BLE only forms a mesh with Bluetooth Mesh, which, as we've seen, works much like Zigbee but is found in fewer home automation gateways and devices.

Conclusion

Zigbee remains more popular and widespread than BT Mesh in home automation devices and gateways, and it has gained momentum with Zigbee 4.0. Bluetooth, in turn, has taken on an important role in the home: many devices are set up over the phone's BLE, including those that use the Matter standard and, now, those that use Zigbee Direct.

The newcomer of recent years is Thread, which uses the same type of radio as Zigbee (IEEE 802.15.4) but speaks IPv6 and is, alongside Wi-Fi, one of the networks Matter runs on. In the home, the choice between Zigbee, Bluetooth, Thread, or Wi-Fi depends on the number of devices, the distances, and the hub that will talk to all of them.