What is SSB (Synchronization Signal Block)

The Synchronization Signal Block (SSB) is a critical component in the 5G New Radio (NR) standard for wireless communication. Let’s dive into the technical details:

1. SSB Burst:
   • The SSB is divided into bursts, each containing synchronization signals.
   • Each SSB burst consists of consecutive symbols, with a fixed number of subcarriers.
   • The number of symbols in an SSB burst depends on the configuration and bandwidth of the SSB.
2. Physical Cell ID (PCI):
   • The PCI is a unique identifier assigned to each cell within the network.
   • It helps user devices (UEs) differentiate between neighboring cells and synchronize with the correct cell.
   • The PCI is embedded in the SSB and is crucial for cell search and initial access.
3. Primary Synchronization Signal (PSS):
   • The PSS aids in initial cell detection and synchronization.
   • It provides coarse timing and frequency synchronization for UEs.
   • The PSS consists of a predefined sequence of complex-valued symbols transmitted over a specific frequency range.
4. Secondary Synchronization Signal (SSS):
   • The SSS provides additional information for fine-grained synchronization and cell identification.
   • It carries the cell identity group and helps determine the exact PCI of the serving cell.
5. Beamforming Reference Signal (BRS):
   • In certain SSB configurations, the SSB may include a BRS.
   • The BRS assists UEs in determining the beamforming configuration of the serving cell for optimal signal reception.
6. Transmission and Detection:
   • The SSB is transmitted using orthogonal frequency-division multiplexing (OFDM) modulation.
   • UEs search for SSB bursts by scanning different frequency ranges and correlating received signals with known PSS and SSS sequences.
   • Once detected, UEs extract the PCI and other synchronization parameters from the received signals, enabling network synchronization.