How Bluetooth® Shorter Connection Intervals will impact the next generation of wireless innovations

Bluetooth® Shorter Connection Intervals (SCI) is a transformative feature that reduces the minimum connection interval for Bluetooth® LE by a factor of 20, from 7.5 ms to just 375 μs. Bluetooth SCI delivers a performance breakthrough, enabling Bluetooth LE devices and applications to exchange data far more frequently, resulting in lower communication latency, improved responsiveness, and a smoother user experience.

Recently, I had a chance to speak with representatives from Nordic Semiconductor, and we discussed the role Bluetooth SCI will play in developing the next generation of Bluetooth solutions. 

Q&A with Nordic Semiconductor on Bluetooth® SCI

How does Nordic Semiconductor view new features introduced in Bluetooth® Core 6.2, and how do you see them shaping the direction of your future products?

There are multiple feature enhancements in Bluetooth® Core 6.2 that are interesting to both Nordic Semiconductor and our customers, but the standout feature with the greatest impact for us is Bluetooth SCI. Additionally, Bluetooth® Channel Sounding Amplitude-based Attack Resilience is important to Nordic, especially in the sense that this highlights the significance of Bluetooth® Channel Sounding as a feature that continues being adopted widely, and that there is continuous and ongoing development at the Bluetooth® Core Specification level to make it even better and push it even further.

We believe that Bluetooth® Core 6.2 marks an eagerly awaited milestone in the development of the Bluetooth® Core Specification and that the features introduced will be an important part of the direction our existing and future products are taking. We are also proud to have played a major role in bringing Bluetooth SCI to life and to be among the first to adopt it.

What key benefits does Bluetooth® SCI bring to high-performance HID devices and other latency-sensitive applications?

Prior to Bluetooth® Core 6.2 and the introduction of Bluetooth SCI, the minimum Bluetooth LE connection interval was 7.5 ms with a resolution of 1.25 ms. This is perfectly sufficient for many typical Bluetooth applications, such as fitness trackers, smart home sensors, and medical devices. However, for latency-sensitive applications that require ultra-fast responsiveness, a 133 Hz update rate, achievable with a 7.5 ms interval, may not be sufficient.

For gaming, consumers expect HID devices such as gamepads and mice to support report rates of 1 kHz or higher. This is where Bluetooth SCI shines: it reduces the connection interval to 375 μs with a resolution of 125 μs, enabling report rates of up to 2666 Hz for wireless HID use cases with Bluetooth LE. This enables the desired 1 kHz update rate for gaming peripherals, along with the interoperability benefits of Bluetooth connectivity, so no dongles are required.

In addition to the gaming HID market, we believe Bluetooth SCI will bring significant benefits to AR/VR controllers, professional HID devices for artists and designers, real-time industrial sensors, and other latency-sensitive use cases, such as real-time location systems.

What made Bluetooth® SCI a priority for implementation, and what insights came from that process?

In addition to being among the first to adopt it, Nordic was also a key contributor to Bluetooth® SCI, which underscores its importance to our customers and us. It is a significant improvement to the previous connection interval, which was limited to 7.5 ms, and, as such, it enables many new use cases requiring ultra-low latencies.

The whole process of bringing Bluetooth SCI to life from start to finish has been full of insights and eye openers, one of them being that Bluetooth, as a technology, continues to hold a strong competitive position and evolves to meet new technical requirements that may initially seem daunting. Much of this success is driven by the determined community behind its development and the powerful commitment of Bluetooth SIG members in working group initiatives.

Can you share more about how Bluetooth® SCI impacts your product portfolio and your target customer base?

The adoption of Bluetooth SCI impacts our whole Bluetooth product portfolio. Supporting Bluetooth SCI across all our Bluetooth enabled devices brings the entire Bluetooth product portfolio to the forefront of Bluetooth development, demonstrating its capabilities.

Adopting Bluetooth SCI also impacts our target customer base; we are excited about the interest and activity we are seeing from both existing and new customers since announcing Bluetooth SCI support in our products. This opens new venues within our target customer base, as Bluetooth SCI is attractive across a variety of use cases.

What types of new use cases does Bluetooth® SCI enable, and how does it enhance existing ones for customers?

In addition to the HID, AR/VR, professional stylus, and real-time industrial sensing use cases, we believe Bluetooth SCI may enable new wearable use cases such as haptic gloves, ultra-low-latency sports performance monitors, VR body trackers, and high-performance modes in AR glasses. Additionally, there can be benefits in wireless medical devices and prosthetics for low-latency modes to improve effectiveness and safety and to avoid instability or unsafe motion.

What types of customers or industries will be most impacted by Bluetooth® SCI?

The main attraction for Bluetooth SCI on our customer side comes from gaming HID device manufacturers, but we also believe it will be of interest in industrial real-time sensing use cases and other application areas where low latency brings benefits, such as AR/VR devices, motion trackers, sports performance monitoring, and real-time positioning.

What are some of the key considerations or potential challenges that Bluetooth developers should keep in mind when making use of Bluetooth® SCI?

The first key consideration for Bluetooth developers is that to fully unlock its potential, it is highly recommended to use the Bluetooth Frame Space Update (FSU) feature introduced in Bluetooth® Core 6.0. Using Bluetooth FSU, the devices can negotiate the lowest possible frame space value to minimize latency, or, in this case, to the minimum.

Another key consideration is related to power consumption: increasing the update rate of the device increases power consumption as data is sent more often, but there are many ways to compensate for this to improve efficiency. Connection Subrating, which is a mandatory requirement for SCI, allows skipping connection events when no data is being sent to reduce the active duty cycle. The recently announced ULL HID profile also notes that HID devices can make use of fast poll-rate switching to rapidly switch between high-performance modes and low-power modes to conserve power. LE Flushable ACL Data can also be used to discard stale data and reduce unnecessary transmissions.

As such, ultra-low-latency HID devices may also consider the right update rates for each scenario. For example, a 1 kHz update rate often strikes the perfect balance between ultra-low-latency and low power consumption.

Looking ahead, what additional Bluetooth® features or capabilities is Nordic planning to add to its Bluetooth products?

Adding support for ultra-low-latency HID on our products using HID SCI is already in our sights and the logical next step. The ultra-low-latency HID project was announced during Embedded World NA 2025, and it is a vital next step to enabling the widespread adoption of low-latency interoperable Bluetooth HID devices, providing sub-ms latencies.

Additionally, we are eagerly looking forward to supporting Bluetooth® Channel Sounding, Inline PCT Transfer, and Inline RTT, as these are interesting and valuable optimizations for our customers working on Bluetooth® Channel Sounding. We are happy to see these features progressing rapidly and on schedule in the Bluetooth® Core Specification Working Group.

High data throughput is another interesting feature that will certainly bring the Bluetooth data transfer and audio use cases to the next level.