LTE: Physical Cell ID (PCI) vs Physical Layer Identity vs Physical layer cell identity group number

Question

What is the difference/relationship between Physical Cell ID (PCI) and Physical Layer Identity and Physical layer cell identity group number?

Answer 1

UE will get to know the Physical Layer Identity after decoding PSS and Physical layer Cell identity group number by decoding SSS.
Now Combining these two Physical Layer Identity (x) + Physical Layer Cell identity group number(3y) , UE will derive the Physical Cell ID.