What is Bluetooth 5.3?

Bluetooth Core Specification Version 5.3 or Bluetooth 5.3 has introduced a number of new feature enhancements which aim to improve reliability, energy efficiency and user experience in a wide range of products.

The primary updates in the Bluetooth Version 5.3 are:

1. Periodic Advertising Enhancement
2. Encryption Key Size Control Enhancement
3. Connection Subrating
4. Channel Classification Enhancement

Periodic Advertising Enhancement: The AdvDataInfo (ADI) field of the common extended advertising payload format may now be included in AUX_SYNC_IND protocol data units (PDUs) which are broadcast when a device is performing periodic advertising. On receiving AUX_SYNC_IND PDUs Bluetooth® Low Energy (LE) controllers may use the information in the ADI field to recognise packets that contain retransmitted copies of identical or semantically equivalent data which has already been successfully received. The controller may then discard the packet rather than pass its content to the host. It may also afford the opportunity for the controller to switch to scanning on a primary channel earlier than would otherwise have been the case and therefore improve RX duty cycle as it applies to those channels.

Encryption Key Size Control Enhancement: In Bluetooth BR/EDR, encryption key sizes are negotiated by the controllers in connected devices. This change will allow a host to inform its Bluetooth BR/EDR controller of the minimum acceptable key size using the Host Controller Interface (HCI). This enhancement will also result in improving the efficiency with which Bluetooth BR/EDR controllers can inform the host of the outcome of key length negotiations.

Connection Subrating: Some product types spend much of their time in a low duty cycle connection so that power is conserved. But when a higher bandwidth is needed to support a particular application use case, the connection parameters must be changed as quickly as possible. Connection Subrating allows connection parameter updates to be made with minimal delay, delivering a better user experience but at the same time, retaining the power saving properties of low duty cycle connections.

Channel Classification Enhancement: Bluetooth LE Peripheral devices are now able to provide a connected Central device with radio channel classification data which may be used by the Central device when performing channel selection during adaptive frequency hopping. This improves throughput and reliability by reducing susceptibility to interference taking place at the Peripheral when the Peripheral and Central devices are not physically close to each other.

Download the Bluetooth Core Specification Version 5.3 Feature Enhancements document.