As the low power, wide-area network (LPWAN) market expands, there are so many more options for low power protocols for Internet of Things (IoT) applications. Within this article, we’re comparing Bluetooth and Bluetooth Low Energy (LE) to ZigBee, so you can get a better idea which wireless protocol to use for your connected devices.
The Difference Between Bluetooth & Bluetooth LE
There are two branches of Bluetooth: traditional Bluetooth and Bluetooth Low Energy (known as Bluetooth LE). The reason why traditional Bluetooth isn’t comparable with ZigBee comes down to power consumption. If an application needs to be battery operated for an extended period of time, traditional Bluetooth simply will not suffice. Traditional Bluetooth design recommends one watt of power consumption. When it comes to wireless IoT applications, this is a lot. Both Bluetooth LE and ZigBee are between 10 to 100 milliwatts (mW), which is 10 to 100 times less than what traditional Bluetooth recommends you design for. However, Bluetooth LE does compare well to ZigBee, which we will discuss in this article.
Bluetooth LE is a personal area network (PAN), so the range is much shorter than ZigBee. The purpose is to be able to connect to devices near a user. Bluetooth LE has a much shorter range than ZigBee, but it also has a much higher data rate. Traditional Bluetooth had a data rate between 1 to 3 Mbit/s, and Bluetooth LE data rate is 1 Mbit/s for short bursts. It “sleeps” in between those bursts —a functionality ZigBee does not have—which requires less data and power usage.
Now, Bluetooth LE is also supported by many operating systems, including Android, iOS, Windows 8/10, and OS X (spaces ZigBee hasn’t branched into). If a user has their smartphone and wants to connect to a device, Bluetooth LE makes that possible. However, Bluetooth isn’t a great choice for high density nodes or long-range applications.
Bluetooth LE Use Case
Bluetooth LE is ideal for someone traveling through a group of connected things in a defined space. When a person gets into their car, Bluetooth LE can make the car “smart” by enabling audio dialing and car-to-phone speaker connection. If they switch from their car to a Bluetooth LE-enabled smart bicycle, the connected application could direct them to the right location. The information doesn’t stay with a Bluetooth LE-enabled device—rather, it leaves with the user.
ZigBee is a mesh network protocol designed to carry small amounts of data across medium distances. It runs on a mesh topology network, meaning information from a single sensor node travels across a group (or “mesh”) of modes until the transmission reaches the the gateway.
ZigBee is a local area network (LAN), so unlike Bluetooth LE, it is not intended to connect to devices directly around a user. Instead, it connects to devices that need a wider range. Because of this, it’s an ideal protocol for home automation and smart lighting.
Despite ZigBee’s wider range, it is still fairly limited and isn’t the best choice for highly instrumented installations, like industrial IoT applications. And because of their mesh topologies, ZigBee networks have higher latencies, which can cause bottlenecks when multiple nodes try to pass through a single node to get to the gateway. Because of this, ZigBee doesn’t shine when there’s a high density of nodes (like in a factory, for example). ZigBee also faces a lot of challenges when link budget is highly variable, like mobile nodes or parking sensors.
ZigBee Use Case
Consider this: You could interface a ZigBee system so when someone walks in their front door, ZigBee would run a whole series of events: turning on their favorite tunes, turning on the lights, turning up the heat, and more. When they leave, a ZigBee application could turn off the HVAC system to conserve energy and save money. Overall, it offers a practical use case for home automation.
Comparison Chart: Bluetooth (Bluetooth LE) Vs. ZigBee
|Network type||Personal area network (PAN), which supports few nodes||Local area network (LAN), which supports many nodes|
|Range*||77 meters||291 meters|
|Operating system||Android, iOS, Windows 8, OS X||Not currently compatible|
|Topology||Mesh and star||Mesh only|
|Throughput||270 kbps||250 kbps|
|Modulation||Frequency-hopping spread spectrum (FHSS)||Direct-sequence spread spectrum (DSSS)|
|Transmit power||10 mW||100 mW|
*This range comparison is based on a specific use case; see the full comparison with additional specifications in this article.
Bluetooth LE and ZigBee are actually quite complimentary to each other. There are times someone would want to use Bluetooth LE for IoT applications, and there are times when ZigBee is a better choice. Only in the last year have ZigBee and Bluetooth started to compete in this space. Some developers are finding that a combination of Bluetooth LE and ZigBee can make for very strong personal and local area network devices.