The next generation of cars will need Bluetooth solutions that support multiple simultaneous Bluetooth connections to different Bluetooth-enabled devices. The passenger might want to stream music from their device, while the driver might want to use their smartphone for hands-free telephony.
OpenSynergy provides the Bluetooth® stack Blue SDK for this use case. It implements Bluetooth profiles that enable advanced audio streaming over Bluetooth Low Energy. A codec, called LC3, makes it possible to stream audio over Bluetooth Low Energy (LE), providing improved audio quality at roughly half the bitrate compared to the traditional Bluetooth audio codec. Additionally, highly synchronized audio streams can be shared across multiple receiving devices via Multi-Stream Audio and Broadcast Audio.
OpenSynergy’s Blue SDK is the right solution to build systems that simultaneously enable multiple connections to multiple devices over multiple Bluetooth profiles. For example, when two drivers enter the car with their smartphones, both phones are automatically paired or connected to the in-vehicle head unit. Both smartphones within the car can run different activities via Bluetooth at the same time. For example, one can play audio streams while the other is downloading phone books.
Blue SDK integrates all required profiles such as HFP (for hands-free telephony) or A2DP and AVCRP for media streaming. The new Low Energy Audio functionality significantly enhances the user experience of Bluetooth audio streaming by improving audio quality, reducing latency, and adding the ability to easily share audio. OpenSynergy’s implementation of LE Audio will continue its legacy of excelling where open source and consumer-grade Bluetooth stacks fall short. In addition to improved audio quality, it connects a lot more devices.
Multi-stream audio allows for multiple, highly synchronized audio streams between an audio source device and one or more receiving devices. For example, a single smartphone can send an independent stream of the Left channel to one Bluetooth speaker and an independent steam of the Right channel to another Bluetooth speaker. Both speakers work together as a single system to play stereo audio.
Broadcast Audio enables an audio source device to broadcast one or more audio streams to many receiving devices. This new topology is referred to as “Audio Sharing.” It is useful for broadcasting audio within public venues as well as sharing audio from the same audio source device with friends. For example, an in-car entertainment system can broadcast the same audio to a large group of passengers that are all wearing headphones, providing the driver with peace and quiet or the flexibility to take a phone call over the built-in sound system.
Completely new Bluetooth profiles, such as Telephony and Media Audio Profile (TMAP), define interoperable support for both telephony and media audio compared to the Classic Audio profiles such as A2DP for media streaming, AVRCP for media controls, and HFP for telephony. This is in contrast to the profiles in the Classic Audio architecture, which cover many functionalities redundantly. The new profile architecture for LE Audio consolidates functionality into smaller underlying profiles that can be reused across use cases. Additionally, LE Audio and the new LE Dynamic Power Control can reduce power consumption and optimize signal strength.