5G NR: PBCH Decoding Process in 5G

When you power on 5G/NR UE(NR Standalone UE) or When LTE is adding NR Cell as a secondary cell, the first thing happening in UE is the process described below. This summary is based on Matlab 5G Toolbox example (Ref [1]) and the implementation on UE may vary a little bit from this.

i) Search Frequency in which SSB (PSS + SCC + PBCH) is transmitted.
ii) Search PSS ==> by detecting PSS, UE can figure out

. This is done in the time domain by calculating the correlation between each reference NID (2) sequences with the received signal. With the correlation calculation, we can figure out the exact timing offset (i.e, exact symbol start timing of PSS) in addition to finding out the best NID(2). This timing value (let's call it as 'offset') is the crucial information to construct the accurate resource grid that is used in step iii) and onwards.

iii) Construct the resource grid from the received signal and the detected timing from step ii)

iv) Search SSS by correlating the extracted SSS REs and calculating the correlation between the extracted SSS and reference SSS ==>By detecting SSS, UE can figure out .

v) By using  and  UE can calculate Physical Cell ID  

vi) Search PBCH DMRS