Understanding LE Audio: BIS and CIS Explored

 

LE Audio, introduced with Bluetooth 5.2, brings significant advancements to audio technology by using the Low Complexity Communication Codec (LC3). 
Compared to older codecs like SBC, LC3 provides better audio quality while reducing power consumption, making it ideal for devices like wireless earphones and hearing aids.

In this article, we’ll explore two key modes in LE Audio: Broadcast Isochronous Stream (BIS) and Connected Isochronous Stream (CIS). These modes cater to different use cases, offering flexible audio experiences.

What is Broadcast Isochronous Stream (BIS)?

BIS enables one-way audio broadcasting from a single source to multiple devices simultaneously without pairing.

Several BIS streams can form a Broadcast Isochronous Group (BIG), allowing synchronized multi-stream transmission, ideal for environments where many users need access to the same audio content, such as events or museum tours. Any device that supports LE Audio can receive the broadcast, making it an accessible and versatile solution for shared audio experiences.

Here’s a chart including BIS and BIG:

Example Use Case: Concerts and Events

Imagine attending a large outdoor concert where BIS technology is used to broadcast live music directly from the stage to the audience’s devices, such as smartphones and wireless earphones. BIS can broadcast live music from the stage directly to attendees’ devices, ensuring everyone hears the performance in real-time, regardless of location.

Example Use Case: Museum Tours

In a museum setting, Broadcast Isochronous Stream (BIS) can be used to deliver audio guides directly to visitors’ smartphones or rented devices. Visitors can receive synchronized audio guides on their smartphones, enriching their experience and offering multi-language support.

What is Connected Isochronous Stream (CIS)?

CIS focuses on direct, device-to-device connections. The audio stream is transmitted between paired devices with two-way communication, creating a connected and dedicated audio experience.

It’s ideal for personalized experiences like hearing aids or wireless earphones. Multiple CIS streams can be synchronized using a Connected Isochronous Group (CIG) for simultaneous audio transmission while maintaining the benefits of a personalized connection.

Here’s a chart including CIS and CIG:

Example Use Case: Wireless Earphones

Imagine a user connecting their wireless earphones to a smartphone via CIS. When two Bluetooth earphones are connected simultaneously, multiple CIS streams can be grouped into a Connected Isochronous Group (CIG) to achieve synchronized audio transmission across both devices and also enables high-fidelity audio streaming, ensuring clear and immersive sound.

With CIS, each user can adjust volume or equalizer settings independently without impacting others, creating a truly personalized listening experience. CIS provides a significant upgrade over traditional Bluetooth audio by delivering richer sound quality with lower latency.

Example Use Case: Hearing Aids

Connected Isochronous Stream (CIS) is especially beneficial for hearing aids, allowing individuals with hearing impairments to directly connect their devices to a TV, smartphone, or other audio sources. CIS enables real-time adjustments to improve speech clarity or reduce background noise, ensuring the audio is clear and effective. Users can have a closer and more immersive audio experience, which is crucial for enhancing social interactions and supporting daily activities.

Summary

BIS vs. CIS: Which Fits Your Needs?

BIS is suitable for shared audio experiences, such as public events and guided tours, where multiple users need simultaneous access.

CIS is designed for personalized audio, offering low-latency and high-quality sound for individual users or synchronized multi-device setups.

LE Audio is set to change everyday audio experiences with richer, more versatile audio solutions. Whether it’s concerts, museums, or hearing aids, BIS and CIS provide innovative ways to enhance audio quality and efficiency.

Edited by Sales Manager: Ms. Mandy Chao

Raytac Corporation 勁達國際電子股份有限公司 

A Bluetooth, Wi-Fi, and LoRa Module Maker based on

Nordic nRF54; nRF53: nRF52; nRF51; nRF7002

Semtech Specification: SX1262

Bluetooth Specification: BT5.4 ; BT5.3 ; BT5.2.

Wi-Fi Specification: Wi-Fi 6

LoRa Specification: LoRaWAN

All products are FCC/IC/CE/Telec/KC/RCM/SRRC/NCC/WPC Pre-Certified.

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