BLE Coded PHY Preamble and Range

[David]

I'm interested in BLE coded phy and am wondering how the improved range is realized given that the preamble is not coded.  In other words, how does the receiver have improved sensitivity when the preamble itself is not actually coded?  Related -- is the RSSI value provided by the softdevice calculated based on the preamble or a packet?  Put differently: should the RSSI value of a coded vs non-coded packet be similar at fixed range holding all other variables constant?

[David]

Understood on the phy/fec and that the the receiver (R) is the one calculating it.

I guess the point is that the SoftDevice exposes fully decoded packets so any RSSI I see from the SoftDevice is reported for a fully decoded packet. So regardless of PHY if I have two links -- only difference is that one is coded and one is not -- and increase distance between them the RSSI should be the same for both links due to exactly what you sated (facepalm moment).  However, at some point the non-coded link will break at increased distance, but the coded link will show RSSI values further decreasing due to the coding/FEC.