Code PHy Mode, Advertisment Power vs. 1M mode

[DanPhelan]

Devices: nrf52840 peripheral to nrf52833 central

background: We switched the mode from BLE_GAP_PHY_1MBPS, to BLE_GAP_PHY_CODED.  The content of the advertisement data was not changed.

power concerns: The current measured in the BLE_GAP_PHY_CODED mode is two times the 1MBPS.  Is this normal?

What should we expect the power difference to be between coded PHY and 1MBPS?

Thanks,

Dan

[Hung Bui]

Hi Dan, 

Coded PHY mode actually use the same 1Mbps modulation to send data, just using more redundancy bit for error correction to achieve longer range. For example with S=8, each bit is represented by eight symbols. So for the same amount of data it will use 8 times more time to transmit. 

You can take a look a this video: https://www.bluetooth.com/bluetooth-resources/intro-to-bluetooth-low-energy-coded-phy/

Note that not only the power consumption is the drawback, the throughput is also reduced to 125kbps when you use S8. 

[DanPhelan]

Hung,

Thanks for the information.  Our measurements make sense.

Dan