Courtesy of Nordic Semiconductor
Bluetooth 5 is the latest version of the Bluetooth specification. It represents the greatest advancements in the specification since Bluetooth 4.0 and the introduction of Bluetooth Low Energy.
There are very exciting new features present that promise to revolutionize the scope, appeal and spread of Bluetooth as the primary connectivity solution on the market. The key introductions are listed below:
Major new features of Bluetooth 5
- High throughput
- Long range
- Advertising extensions
- Increased broadcast capacity
- Improved co-existence
Bluetooth 5 ready
The new Bluetooth 5 features for high throughput, long range and advertising extensions offer truly exciting possibilities for home, industry and commerce as well as the more traditional areas of wearables and personal devices historically associated with Bluetooth. At Nordic we understand what developers want, and when they want Bluetooth 5, they want these features. That’s why we built the nRF52 Series SoCs and the software that supports them to take advantage of them.
This means when you choose Nordic you can start the journey of developing with this exciting technology and can utilize these new features. Under the rules of Bluetooth SIG a device can claim to be Bluetooth 5 compliant by merely supporting the errata completion. That means fixing what was missing or wrong in 4.2, but with no support for the key new features.
At Nordic we don’t think that’s right. We know you want the new features, that’s why when Nordic says we support Bluetooth 5, we support the new features of high throughput, long range and advertising extensions, because we know at the end of the day, that’s what you’re looking to add to your applications.
Higher data throughput
The data rate for Bluetooth low energy has now been extended from a singular transmission speed (1Mbs) to four discrete data rate speeds as seen in the list above. The maximum speed is doubled to 2Mbs. Together with advancements introduced in Bluetooth 4.2 which allowed for Data Length Extensions (DLE) overall throughput is x5 higher than the original Bluetooth 4.0 level. Now net data throughput not including overhead such as addressing can be as high as 1.4Mbs. Data packet size, datarate and overall data throughput are illustrated in fig. 1.
Fig. 1 Bluetooth 5 data packet size/throughput chart
This increase offers opportunities for new applications that simply need more data throughput than was possible previously. It also enables much faster Over the Air Device Firmware Upgrades (OTA-DFU).The nRF52840, like all members of the nRF5x series Socks is a flash-based SoC thus enabling it to take advantage of this increased speed to perform firmware updates and for uploading data in bulk fashion.
Bluetooth 5 introduced significant changes at the physical (PHY) layer for Bluetooth radio operation. Four data rates are now available 2Mbps, 1Mbps, 500kbps and 125kbps. The 2Mbps clearly offers higher throughput possibilities. Why offer lower datarates of 500kbps and 125kbps some may ask. The reason for these is that at these lower datarates and with the associated LE Coded processing using Forward Error Correction (FEC) it becomes easier to retirieve data transmissions in surrounding noise. In short, the sensitivity improves, specifically by around 12dB.
In RF terms 6dB improved gain in the link budget is a theoretical doubling of range, therefore 12dB improvement increases range possibilities fourfold. Link budgets can be improved by additional power, but critically the long range improvements in Bluetooth 5 do not rely on improved output power and mean up to four times more range can be achieved without a need to increase peak output power. The data throughput capacity does of course reduce when 500kbps or 125kbps modes are selected, but for many Bluetooth low energy applications which are relatively straightforward sensing and actuating applications, these data rates are perfectly adequate.
Increased broadcasting capacity
Advertising extensions are introduced to alleviate advertising channel occupancy and potential channel congestion. Data Length Extensions and a new PHY layer means longer packet lengths in terms of actual data and the length of time they occupy a channel. As only 3 advertising channels exist these channels could soon become congested with advertising packets with large data payloads at lower on-air transmission speeds such as 125kbs.Advertising extensions mitigates this potential issue by advertising on the 3 advertising channels as previously, but the data to be sent is on an agreed non-advertising channel.
Fig. 2 Advertising extensions allocation of channel for advertising data
An additional feature of Advertising extensions is the ability to chain advertising packets to create extended advertising data payloads seen in fig. 3
Fig. 3 Advertising extensions ‘chaining’ of advertising data packets
Periodic advertising allows for more synchronized broadcasting of data between devices. In this mode periodic advertising happens at a deterministic periodic interval thus allowing true connectionless broadcasting.
Improved coexistence with improved channel hop sequencing
Bluetooth 5 has also introduced an improved Channel Sequencing Algorithm (CSA #2) to improve the pseudo randomness of next hop channel sequencing. CSA #2 will improve coexistence performance of enabled devices in the presence of WiFi, other Bluetooth devices. All of the nRF52 Series SoCs have the ability to support CSA #2.
All of the nRF52 Series SoCs multi-protocol SoCs have been designed to take advantage of these significant performance advancements of Bluetooth 5. Additionally, the nRF52840 has improved output power of 8dB which together with new long range features in Bluetooth 5 offer significant new application possibilities requiring longer range communication.
nRF52 Series SoC Bluetooth 5 feature support
|Bluetooth 5 features||nRF52840||nRF52832||nRF52810|
|Long range (x4)||X|
|Higher throughput (x2)||X||X||X|
|Increased broadcast capacity (x8)||X||X||X|
|Improved channel co-existence algorithm (CSA)||X||X||X|
|nRF52840||Multi-protocol Bluetooth 5/Bluetooth low energy/ANT/802.15.4/2.4GHz RF SoC|
|nRF52832||Multi-protocol Bluetooth 5/Bluetooth low energy/ANT/2.4GHz SoC|
|nRF52810||Multi-protocol Bluetooth 5/Bluetooth low energy/ANT/2.4GHz SoC|
|nRF52840 Preview DK||Development kit for nRF52840 SoC|
|nRF52 DK||Development kit for nRF52832 and nRF52810 SoC|
|Nordic Thingy:52||IoT Sensor Kit with nRF52832 SoC|
|S140||Bluetooth 5 protocol stack for nRF52840|
|S132||Bluetooth 5 protocol stack for nRF52832 and nRF52810|
|S112||Bluetooth 5 protocol stack optimized for nRF52810|
|nRF5 SDK||Software Development Kit for nRF51 and nRF52 Series|