LTE Synchronization Signals (PSS and SSS)

Initial Acquisition

In frequency Acquisition we will get

  • Band Information (Supported Band Info)
  • EARFCN Information (Defined EARFCN)
  • PLMN Information

Need to know

  • PLMN and EARFCN information will be provided by SIM.
  • Band Information will be provided by Phone (system file).
  • Now work of UE is to obtain time and frequency synchronization.
  • So the first signal to be detected is PSS then SSS in Time domain and frequency domain.
  • From PSS and SSS the PCI ID decoding will be done.

PSS (Primary Synchronization Signals)

  • PSS is used for Slot Synchronization.
  • Position of PSS in time domain (1st Subframe,1st Timeslot,7th OFDM Symbol).
  • Periodicity -5 ms.
  • In frequency domain across the 7th OFDM symbol depending of variable bandwidth.
  • PSS is decoded on Centre frequency, where minimum 6RB is required i.e 62 subcarrier.
  • If it will 1.4 Mhz it will be across the bandwidth.
  • Centre frequency is required because it is having higher gain.

PSS Information Elements

  • Subframe Number.
  • Cell number, PSS records.
  • PSS Indices. (0,1,2)
  • Peak Position.

SSS (Secondary Synchronization Signals)

  • SSS is used for Frame Synchronization.
  • Position of SSS in time domain (1st Subframe,1st Timeslot,6th OFDM Symbol).
  • Periodicity -5 ms.
  • In frequency domain SSS is decoded on Centre frequency, where minimum 6RB is required i.e 62 subcarrier.
  • If it will 1.4 Mhz it will be across the bandwidth.

SSS Information Elements

  • EARFCN.
  • Cell ID number.
  • Frame Boundary Information.
  • Cyclic Prefix
  • Number of Barred/detected cell.


Categories: LTE,5G,TELECOMMUNICATION

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