Silicon Labs: Bluetooth® 5, Refined for the IoT

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This whitepaper introduces the new features of Bluetooth 5 technology and how they enable the next wave of IoT applications. The hallmark features of Bluetooth 5 include twice the speed, four times range, and eight times the advertising capacity for long range, more robust connections, better user experience, and smarter beacons.

 

Refined for the IoT

The rapidly evolving and expanding IoT market provides big opportunities for device manufacturers. New applications and the huge increase of devices requiring wireless connections has also kept various wireless standard interest groups busy developing new standards or updating existing ones to fulfill IoT-specific needs.

The projected market growth for IoT-related applications and devices varies but one estimate puts the figure at around 16% CAGR up to the year 2025 [1]. This wide range of IoT applications will require the use of not one but several wireless standards if all usage scenarios are to be realized. This in turn also implies that coexistence issues need to be addressed adequately. The increased demand for suitable gateway devices is obvious.

According to market share estimates, Bluetooth will be used in 60 percent of all wireless devices by the year 2021 and Bluetooth low energy correspondingly in 16 percent of devices. Most of the increase will be seen in smart home, beacon, connected home, and wearables applications[2]. According to the computer magazine Datamation, ABI Research is expecting Bluetooth with low energy shipments to have a CAGR of 34 percent between 2016 and 2021[3]. Such growth requires the wireless standards to be extremely robust and dependable. What is also needed are manufacturers who utilize the possibilities allowed by the wireless standards to the maximum in their hardware offering and who provide easy-to-use and powerful software stacks.

Bluetooth has already existed for almost 20 years and is used today in approximately 8.2 billion devices, so it has already demonstrated its robustness and dependability. To fulfill requirements set forth by the new IoT scene, the Bluetooth SIG announced the Bluetooth 5 specification in December 2016. The latest Bluetooth standard improves bandwidth, range, broadcasting, and coexistence features.

 

2x Speed

One of the major features in Bluetooth 5 is a new 2 Mbps PHY. Bluetooth 4.x devices only support a single 1 Mbps PHY rate, but Bluetooth 5 devices are capable of supporting either the 1 Mbps or 2 Mbps PHY rates. By doubling the PHY rate, the amount of data that devices can transfer is almost doubled as shown in the table below. Another benefit of the faster PHY is the reduced time required for transmitting and receiving data, which translates to a lower average current consumption. This is explained by the fact that more time can be spent in low-power sleep modes.

 

Comparison of 1M and 2M Bluetooth low energy PHYs

PHY Symbol rate Error-detection Range multiplier PDU Length Minimum packet time Maximum packet time Maximum throughput
1M 1 M symbols/s CRC 1 x 0 – 257 B 80 µs 2.12 ms 800 kbps
2M 1 M symbols/s CRC 0.8 x 0 – 257 B 44 µs 1.064 ms 1438 kbps

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