Bluetooth LE High Data Throughput Targets Speeds of Up to 7.5 Mbps

Bluetooth SIG is preparing Bluetooth High Data Throughput (HDT), a major enhancement for Bluetooth Low Energy. The upcoming feature is designed to raise the maximum data rate from 2 Mbps to 7.5 Mbps while maintaining low-power operation, reliability and security.

Nearly Four Times the Bluetooth LE Data Rate

The Bluetooth Special Interest Group (SIG) is preparing Bluetooth High Data Throughput, or Bluetooth HDT, for an upcoming release of the Bluetooth Core Specification.

HDT is designed to increase the maximum Bluetooth LE data rate from today's 2 Mbps to up to 7.5 Mbps. The additional bandwidth addresses growing requirements for high-quality audio, firmware updates, sensor data, wearables and industrial or medical devices.

According to Bluetooth SIG, early member implementations indicate that a multi-megabyte transfer taking around 16 seconds today could potentially be completed in approximately four seconds with HDT.

New PHY With Higher-Order Modulation

The speed increase is enabled by a new Bluetooth HDT Physical Layer, or PHY.

HDT supports data rates of 2, 3, 4, 6 and 7.5 Mbps. Higher-order modulation techniques, including forms of Quadrature Phase Shift Keying (QPSK) and Quadrature Amplitude Modulation (QAM), allow more information to be encoded in each radio symbol.

Coherent detection is used to support reliable signal decoding and maintain robust connections at the higher transmission rates.

Forward Error Correction and Adaptive Data Rates

Bluetooth HDT also introduces forward error correction at the physical layer. Additional redundant information allows receivers to detect and correct certain transmission errors without requiring the complete packet to be retransmitted.

The technology can dynamically change its transmission rate from packet to packet. If radio conditions deteriorate because of interference or distance, devices can automatically switch to a lower HDT rate to maintain a stable connection.

An optional link-quality feedback mechanism can additionally provide information such as RSSI and SNR.

Larger Packets, More Efficient Retransmissions

HDT introduces a new packet structure supporting payloads of more than approximately 8,000 bytes in its largest mode.

Data can be divided into smaller blocks, each with its own checksum. If one block is corrupted, only that block has to be retransmitted instead of the complete packet.

This approach is designed to increase throughput while improving reliability and reducing unnecessary radio activity.

Higher Throughput With Low-Power Operation

Higher speed does not mean abandoning Bluetooth LE's focus on energy efficiency.

Because larger amounts of data can be transferred in less time, the radio can return sooner to a low-power state. Forward error correction and selective retransmission can further reduce the energy required per transferred bit.

This is particularly relevant for battery-powered wearables, sensors and industrial IoT devices that periodically need to transmit larger datasets.

Security Expanded for High-Speed Connections

Bluetooth HDT continues to use established technologies including Elliptic Curve Diffie-Hellman for key exchange and AES encryption.

The specification adds Message Integrity Check options of 64 and 128 bits, compared with the 32-bit MIC used by current Bluetooth LE PHYs. A new Encryption Key Schedule manages transitions between existing GFSK-based and HDT PHYs and supports features including separate encryption keys and Perfect Forward Secrecy.

New Opportunities for Audio and IoT

The additional bandwidth could expand Bluetooth LE into more data-intensive applications.

Potential use cases include higher-resolution and lossless Bluetooth LE Audio, faster over-the-air firmware updates, rapid file transfers and high-rate sensor communication.

Multi-sensor IoT devices, advanced wearables, industrial systems and medical equipment producing large data bursts could particularly benefit from the additional throughput.

Bluetooth HDT is also part of a broader roadmap that includes work on new 5 GHz and 6 GHz frequency bands and IPv6 transport over Bluetooth LE.

Bluetooth SIG expects HDT to be adopted in an upcoming Bluetooth Core Specification release anticipated for late 2026.

Read more: Explore the full technical details of Bluetooth High Data Throughput (HDT) in the Bluetooth SIG article.