What i have understood from your query, Going to write the answer below.
There are three synchronization requirements in LTE:
- Symbol timing acquisition by which the correct symbol start is determined.
- Carrier frequency synchronization which mitigates the effect of frequency errors resulting from Doppler shift and errors from electronics.
- Sampling clock synchronization.
If a User Equipment wishing to access the LTE system follows a cell search procedure which includes a series of synchronization stages by which the UE determines time and frequency parameters that are necessary to demodulate downlink signals, to transmit with correct timing and to acquire some critical system parameters.
There are two cell search procedures in LTE: One for initial synchronization and another for detecting neighbour cells in preparation for handover.
In both cases, the UE uses two special signals to broadcast on each cell:
Primary Synchronization Sequence (PSS) and Secondary Synchronization Sequence (SSS).
The detection of these signals allows the UE to complete time and frequency synchronization and to acquire useful system parameters such as cell identity, cyclic prefix length, and access mode (FDD/TDD). At this stage, the UE can also decode the Physical Broadcast Control Channel (PBCH) and obtain important system information.
