Last month, Bluetooth Core 6.2 made a change I have wanted for years. It solves a long-standing pain point in Bluetooth LE when you care about real-time response. Back when I was building low latency MIDI controllers at ACPAD, we were operating in the BLE 4.0 era. On that, I could move plenty of bits, but not shorter data faster. The main issue was the connection timing.
In BLE, a connected link wakes up in repeating connection events. The connection interval is the time between those events. Until 6.2, the minimum connection interval was 7.5 ms, which means your worst case packet can wait 7.5ms for the next connection, even before protocol overhead delays. For tight MIDI timing in real time instrument playing, this delay feels like a sound lag for professional musicians.
BLE 6.2 introduces Shorter Connection Intervals(SCI), pushing the minimum down to 0.375 ms when both devices support it. This means you can send small packets of data faster. In practice, that means you can get a polling rate over 1kHz. This is a big deal of HID devices like mouse. Gamers don’t use wireless BLE mouse for this exact reason. You will see a large boom in wireless BLE mouse and fall in the mouse with 2.4GHz USB dongles where this limit is not applicable.
Please note that your raw on-air speed is still based on the 2M LE PHY and that has not increased. Shorter intervals just reduce waiting time between opportunities to send small packets.
BTW, do not treat the smallest interval as a default setting. More transfers mean more battery loss. A better option is adaptive timing, meaning run a longer interval while idle, then negotiate a shorter one only during interaction, and return to a longer interval when activity stops. A 6.2 connection still starts at ≥7.5 ms and only then negotiates shorter intervals.
BLE 6.2 can mark some input packets as “flushable”. If packet loss conditions delays them, BLE can drop the old ones instead of sending them late. Good for mice or MIDI, as the late updates feel worse than a missed one.
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