Like LTE, 5G NR also has synchronization signal and known as Primary Synchronization signal (PSS) and Secondary Synchronization signal (SSS). These signals are specific to NR physical layer and provides following information required by UE for downlink synchronization.
- PSS provides Radio Frame Boundary ( Position of 1st Symbol in a Radio frame)
- SSS provides Subframe Boundary (Position of 1st Symbol in a Subframe)
- Physical Layer Cell ID (PCI) information using both PSS and SSS
Physical Layer Cell ID
In 5G New Radio, there are 1008 unique physical-layer cell identities and it is given by
where
- N (1) ID = Secondary Synchronization Signal (SSS) and its range is from {0, 1….335}
- N (2) ID = Primary Synchronization Signal (PSS) and its range is from {0, 1, 2}
Physical Cell ID (PCI) Calculation:
For example a 5G-NR cell has SSS value as 303 and PSS value as 1 then Physical Cell ID will be
3 x 303 + 1 = 909 + 1= 910
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