BLE Connection Parameters: Optimizing Power and Latency
Connection interval, slave latency, and supervision timeout
Connection Parameters Optimization
Once a BLE link is established, three parameters govern timing and power behavior: connection interval, peripheral can skip." data-category="Fundamentals">slave latency, and supervision timeout. Tuning these correctly is one of the most impactful optimizations in BLE product development.
Connection Interval
The connection interval defines how frequently devices exchange packets in a connection event. Specified in units of 1.25 ms, range 7.5 ms to 4000 ms.
| Interval | Use Case | Avg Power | Latency |
|---|---|---|---|
| 7.5 ms | Real-time control, HID | High | < 10 ms |
| 15–30 ms | Continuous sensor streaming | Medium-high | < 30 ms |
| 100 ms | Periodic sensor notifications | Medium | ~100 ms |
| 500 ms | Background sync, OTA chunks | Low | ~500 ms |
| 1000–4000 ms | Deep sleep sensors | Very low | Seconds |
iOS enforces a minimum of 15 ms and recommends 100–1000 ms for background apps. Android allows shorter intervals.
Slave Latency
Slave latency allows a peripheral to skip up to N consecutive connection events without responding when it has no data. A peripheral with slave latency = 9 and interval = 100 ms wakes only every 1000 ms at idle while maintaining 100 ms response latency when data is queued.
Supervision Timeout
The supervision timeout must exceed (1 + slave_latency) × connection_interval × 2.
| Timeout | Behavior |
|---|---|
| 100 ms | Fast disconnect detection, higher reconnect overhead |
| 1000 ms | Balanced for most consumer apps |
| 6000 ms | Tolerant of interference |
Advanced Throughput Features
| Feature | BLE Version | Benefit |
|---|---|---|
| DLE | 4.2 | Up to 9× throughput via 251-byte LL PDU |
| LE 2M PHY | 5.0 | 2× throughput, lower time-on-air |
| Connection subrating | 5.3 | Low-latency wake without renegotiation |
DLE increases the Link Layer PDU payload from 27 to 251 bytes, amortizing packet overhead across larger payloads without shortening the interval. Connection subrating allows skipping base intervals (factor 1–500), enabling fast transitions between active and idle modes.
Use the BLE Power Estimator to model the combined effect of interval, latency, PHY, and DLE. For the advertising phase before connection, see Advertising and Scanning.
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