Bluetooth LE Audio | Next-Gen Low-Energy Audio Solution

Overview

Bluetooth Low Energy (LE) Audio is a wireless audio transmission solution based on Bluetooth Low Energy technology. It significantly reduces power consumption while maintaining audio quality and transmission stability, making it ideal for long-lasting and portable devices. LE Audio is compatible with classic audio scenarios and introduces new applications.

Existing Audio Scenarios (Upgraded):

High-Quality Media Listening: Previously implemented via the Classic Bluetooth A2DP profile, this is now integrated and upgraded within LE Audio, delivering higher audio quality at lower power consumption.
Two-Way Voice Calling: Previously implemented via the Classic Bluetooth HFP profile, this has also been seamlessly transitioned into LE Audio.

Brand New Audio Scenarios:

Multi-Stream Audio: The core technology that enables independent and synchronized dual-ear connections for the next generation of TWS (True Wireless Stereo) earbuds.
Standardized Hearing Aids: Previously, hearing aids heavily relied on proprietary protocols like Apple MFi. LE Audio introduces the unified HAP (Hearing Access Profile) for industry-wide standardization.
Auracast™ Broadcast Audio: An innovative scenario exclusive to LE Audio, allowing a single audio source (e.g., an airport TV) to simultaneously broadcast audio to an unlimited number of receiver devices (e.g., passengers’ headphones).

Basic Mechanism

LE Audio Specifications

The architecture of the LE Audio Specification consists of several distinct modules:

The Bluetooth Core Specification serves as the foundation, providing essential features such as Connected Isochronous Stream (CIS) and Broadcast Isochronous Stream (BIS).
LC3 is a high-quality, low-power audio codec.
The Generic Audio Framework Specifications define a versatile middleware solution for audio transmission and management.
The Use Case Specific Profiles define interoperable support for audio use cases.

Unicast Audio

Unicast Audio supports bidirectional, one-to-one audio stream between two connected devices. Unicast Client creates an LE connection and CIS with Unicast Server to send and receive audio stream.

Broadcast Audio

Broadcast Audio supports unidirectional, one-to-many audio stream. Broadcast Sink synchronizes with Broadcast Source and receives audio stream. Broadcast Assistant can assist Broadcast Sink to select and synchronize with Broadcast Source.

BAP Roles

BAP defines six roles, with specific functions referenced in the table.
Developers can determine if the corresponding BAP roles are supported based on the capabilities of the IC and the LL Features support requirements in the table.
For specific applications, developers can check if the roles defined in the use case profiles are supported according to the requirements for BAP roles in the use case profiles.

BAP Role	Function	LL Feature Supported Requirements
Unicast Server	Provides bidirectional audio streams within established connections, suitable for devices like headphones and speakers requiring stable, interactive connections.	LE Extended Advertising CIS Peripheral
Unicast Client	Initiates connections to Unicast Servers and exchanges audio data, typically implemented in control devices such as smartphones and computers.	LE Extended Advertising CIS Central
Broadcast Source	Transmits unidirectional audio streams to multiple receivers without connections, ideal for public broadcasting systems or Auracast™ shared audio.	LE Extended Advertising LE Periodic Advertising Isochronous Broadcaster
Broadcast Sink	Receives audio streams from Broadcast Sources without connection establishment, enabling synchronized audio reception across multiple devices.	LE Extended Advertising LE Periodic Advertising BIS Synchronized Receiver
Broadcast Assistant	Auxiliary role managing parameter synchronization for broadcast sources and coordinating synchronization between receiving devices, enhancing broadcast efficiency and stability.	LE Extended Advertising LE Periodic Advertising PAST Sender (optional)
Scan Delegator	Delegates scanning of broadcast source metadata and relays information to other devices, streamlining the scanning process for receivers.	LE Extended Advertising LE Periodic Advertising PAST Recipient (optional)

Technical Specifications

Requirements	Content
Feature Support Requirements	LE Extended Advertising LE Periodic Advertising CIS Peripheral CIS Central Isochronous Broadcaster BIS Synchronized Receiver PAST Sender PAST Recipient
Generic Audio Framework Specifications	Basic Audio Profile (BAP) Published Audio Capabilities Service (PACS) Audio Stream Control Service (ASCS) Broadcast Audio Scan Service (BASS) Media Control Profile (MCP) Media Control Service (MCS) Call Control Profile (CCP) Telephone Bearer Service (TBS) Coordinated Set Identification Profile (CSIP) Coordinated Set Identification Service (CSIS) Microphone Control Profile (MICP) Microphone Control Service (MICS) Volume Control Profile (VCP) Volume Control Service (VCS) Volume Offset Control Service (VOCS) Audio Input Control Service (AICS) Common Audio Profile (CAP) Common Audio Service (CAS)
Use Case Profiles	Telephony and Media Audio Profile (TMAP) Hearing Access Profile (HAP) Hearing Access Service (HAS) Public Broadcast Profile (PBP)
Communication Topologies	Unicast Audio Connection-Oriented Bidirectional or Unidirectional Broadcast Audio Connectionless Unidirectional

Usage Scenarios

Connection-Oriented Multi-Stream Audio

An audio source device can transmit multiple synchronized audio streams to one or more connected audio sink devices.

Product: Earbuds

Hearing Aids

LE Audio defines profiles for hearing aids that adapt to various surrounding environments and application scenarios, enabling individuals with hearing impairments to more efficiently enjoy the benefits and convenience of wireless audio technology.

Product: Bluetooth Hearing Aids

Audio Sharing

Broadcast audio enables people to share audio more conveniently and efficiently.

Product: Broadcast Tour Guide Device

Connectionless Multi-Stream Audio

Broadcast audio supports multiple audio streams such as languages to cater to diverse needs of users.

Product: Broadcast Fitness Audiovisual Devices

Bluetooth Profiles > Bluetooth® LE Audio