Bluetooth 5

Taking Bluetooth further

Bluetooth 5 Ready and Able

Brief intro to what's new in Bluetooth 5

Bluetooth 5

is the most significant advancement in the Bluetooth standard since the introduction of Bluetooth low energy in Bluetooth 4.0. It is taking Bluetooth to the next level and is making brand new use cases possible and improving existing ones.

There are four significant new features of Bluetooth 5:

  1. A higher datarate of 2Mbps.
  2. A long range mode with better sensitivity at two new lower datarates of 500kbps and 125kbps.
  3. An 8 x improvement in broadcast capability with advertising extensions.
  4. An improved channel selection algorithm (CSA #2) which enables improved channel coordination and coexistence efficiency with other Bluetooth and non-Bluetooth traffic.

The nRF52 Series multiprotocol SoCs are high performance that support Bluetooth 5. The nRF52840 supports all new features of Bluetooth 5, whilst the other members support all Bluetooth 5 features with the exception of the long range modes. The nRF52 Series family of devices cover baseline through general purpose up to highly sophisticated Bluetooth 5 devices.  All devices in the family are supported by qualified, high performance, production-grade software stacks. Together they offer an unparalleled development option for creating products with Bluetooth 5.

Optional Features

That make all the difference

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.

Bluetooth 5 throughput
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.

Longer range
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

Advertising extensions ‘chaining’ of advertising data packets

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.

nRF52 Series Bluetooth 5-ready SoCs
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.

Advertising extensions allocation of channel for advertising data

nRF52 Series is Bluetooth 5

Bluetooth 5 feature overview

Bluetooth 5  nRF52810 nRF52811
nRF52832  nRF52840 
2 Mbps Yes Yes Yes Yes
CSA #2 Yes  Yes Yes Yes
Advertising Extensions Yes *) Yes Yes
Long Range
Yes *)

Yes *) Software support planned