For a UE to access to the network, first it has to latch on to a network. For that UE needs to find the cell and synchronize it in frequency and time domain. After that it needs to read system information.
This will be done with the help of PSS and SSS.
PSS: Primary Synchronization Signal: It has 3 different code sequence.
SSS: Secondary Synchronization Signal: It has 336 different code sequences.
So there will be a total of 3 * 336 = 1008 possible code sequences.
This value will determine PCI Physical Cell Identity.
PSS:
It is used for radio frame synchronization.
It is mapped to 127 active sub carriers around the center of SSB.
It is made up of 127 m-Sequence Values. In LTE, it is made up of Zadoff-chu sequence.
It is used for Downlink Frame Synchronization.
It is used to determine PCI.
SSS:
It is mapped to 127 active sub carriers around the lower end of the system bandwidth
It is made up of 127 m-Sequence Values
It is used for Downlink Frame Synchronization
It is used to determine PCI.
PCI:
We use below formula to calculate PCI:
N^(1) is SSS range from 0 to 335.
N^(2) is PSS range from 0,1, 2
Example:
If PSS = 1 and SSS = 303 then PCI = 3 *303 + 1 = 910
Read more at TS 38.211 NR
