Coded PHY, introduced in Bluetooth 5.0, is a physical layer (PHY) configuration designed to significantly extend the range of Bluetooth Low Energy (BLE) connections. It achieves this by employing error correction coding, improving the signal's resilience to interference and enabling communication over longer distances. This comes at the cost of reduced data rate, as it increases the number of symbols per bit (with possible values of either 2 or 8).
How Coded PHY Works
Coded PHY uses error correction techniques to improve the reliability of data transmission. This means that even if some parts of the signal are corrupted during transmission, the receiver can still reconstruct the original data. While using the same transmit power as the LE 1M PHY, the modulation of data within the PHY is altered. The payload is coded at either 125 kbps or 500 kbps, depending on the specific implementation. This enhanced bit error detection and correction allows for a longer communication range while maintaining an acceptable bit error rate (BER).
Benefits of Using Coded PHY
- Extended Range: The primary advantage is the significantly increased range compared to the standard 1M PHY. This is crucial for applications requiring longer-distance communication.
- Improved Reliability: Error correction coding makes the transmission more robust against interference and noise, resulting in more reliable data transfer.
Drawbacks of Coded PHY
- Lower Data Rate: The trade-off for extended range is a reduced data rate. This makes it unsuitable for applications requiring high-speed data transfer.
When to Use Coded PHY
Coded PHY is ideal for applications where maximizing range is prioritized over data rate, such as:
- Asset Tracking: Locating and monitoring assets over a wider area.
- Beaconing: Broadcasting signals over long distances for various purposes.
- Industrial Automation: Communicating between devices in large industrial environments.
