Bluetooth 5 and its role in the Internet of Things

What is Bluetooth 5?

If you own a car or a smartphone, you’ve most likely used Bluetooth at least once in your life. Bluetooth is everywhere: speakers, wireless headphones, cars, wearables, medical devices, even shoes!

There are two kinds of Bluetooth devices: one is called Classic Bluetooth (used in wireless speakers, car infotainment systems, and headphones), and the other is called Bluetooth Low Energy (BLE).

BLE is more prominent in applications where power consumption is critical (such as battery-powered devices) and where small amounts of data are transmitted infrequently (such as sensor applications).

These two types of Bluetooth devices are incompatible with each other (even if they are of the same brand or even have the same specification documents). Classic Bluetooth devices cannot communicate directly with low-power Bluetooth devices. However, there is a dual-mode Bluetooth device on the market, which supports both low-power Bluetooth and classic Bluetooth.

Since many IoT systems involve small devices and sensors, Bluetooth Low Energy (BLE) has become the more common protocol of the two (relative to Classic Bluetooth) in the IoT. In December 2016, the Bluetooth Special Interest Group (SIG), the governing body behind the Bluetooth standard, released Bluetooth version 5.0. Most of the enhancements and features introduced in this version focus on Bluetooth Low Energy.

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What are the new features of Bluetooth 5.0?

So, what’s new in Bluetooth 5.0 compared to previous versions?

Three main functions:

• Twice the speed
• Four times the range
• Eight times the advertising message capacity

Let’s take a closer look at each of these and see what potential IoT applications could leverage them.

1. Twice the speed

In earlier versions of Bluetooth (4.2 and earlier), the data rate of Bluetooth Low Energy (BLE) was set to a fixed 1Mbps. In Bluetooth 5.0, a new mode with a data rate of 2Mbps was introduced. This new data rate also provides some additional benefits:

• Since the same amount of data is transferred in a shorter time, power consumption is reduced.
• Improved wireless coexistence due to reduced radio on-time.

One disadvantage of using 2Mbps mode is that it has the potential to reduce transmission range because the higher speed causes the receiver radio to be less sensitive. However, for applications where sacrificing a little range for higher data speeds is acceptable, there are some scenarios where this is acceptable.

Compared to other low-power wireless protocols (e.g. ZigBee, Z-Wave, Thread), BLE offers higher data rates, even at the original 1 Mbps data rate. With the addition of the new high-speed mode (2 Mbps), more potential IoT applications become more feasible. Examples include video streaming, audio streaming, and bursty large data transfers, such as images.

2. Four times the range

Bluetooth 5.0 also introduces a long-range mode that utilizes an error correction technique called forward error correction (FEC). FEC allows the receiver to recover data from errors caused by noise and interference. Therefore, when an error occurs, the receiver can use the redundancy in the data to recover the data originally sent, rather than requiring the data to be resent.

This long range mode is called Coded PHY mode. The obvious benefit of using this new mode is the increased transmission range, the disadvantage is the increased average power consumption and lower transmission rate (125 kbps or 500 kbps, depending on the coding scheme used).

When tested in long range mode, line-of-sight ranges of up to 800 meters have been recorded. This makes it possible to use BLE in applications where communication with devices hundreds of meters away is required. Examples include remote control devices, home automation, and industrial applications.

Bluetooth 5.0 will increase the communication distance to four times the original. This means that BLE technology can finally be used in smart homes. Users can use BLE to control smart products at home, from smart bulbs to smart locks. Now all smart devices in a home can be connected using BLE. Compared with WiFi technology, which consumes a lot of power, the advantages of BLE in smart home products are very obvious.

3. Eight times the advertising message capacity

In Bluetooth Low Energy (BLE), there are three main states a device can be in, it is advertising, scanning or connecting. To connect two Bluetooth Low Energy devices, one device must advertise and the other must scan and then initiate a connection. Advertising essentially involves advertising packets, which allow another scanning device to discover them, after which the scanning device can decide to initiate a connection.

In earlier versions of Bluetooth, the advertising data payload size was capped at 31 bytes. In Bluetooth 5.0, a new advertising mode was introduced: Extended Advertising. Extended Advertising allows up to 255 bytes of payload data to be sent per packet, instead of the original 31-byte limit.

Advertising is available in all low-power devices, but one prominent application that takes advantage of this state is beacon technology. A beacon device maintains an advertising state and simply advertises data for others to browse and read. With the increase in advertising data capacity in Bluetooth 5, beacons can now transmit even more data, unlocking more new IoT applications and uses.

in conclusion

As we can see, Bluetooth 5.0 introduces some features that have a wide range of potential IoT applications. However, there are a few key points to note:

• According to the official Bluetooth specification, the new long-range and high-speed modes are only optional features, so a chipset or device that claims to support Bluetooth 5 may not support these two new modes.
• To be able to take advantage of these new features, the two BLE devices that are communicating with each other need to support Bluetooth 5 and support the features of interest. For example, to be able to utilize the long range mode to transmit sensor data over a long distance between a sensor device and a smartphone, both the sensor device and the smartphone need to support Bluetooth 5 and the long range mode.
• It’s still difficult for smartphones to support Bluetooth 5 and its new features. Even if new hardware supports it, its API needs to allow mobile developers to use these features.

However, despite this, the potential new IoT applications introduced by Bluetooth 5, both on the mobile and embedded side, are bound to see widespread adoption!