5G • RAN

Treselection

Cell Re-selection Evaluation Timer

Timer requiring a neighbor cell to remain higher-ranked than the serving cell before re-selection occurs.

Technical Explanation

Broadcast in SIB2 (t-ReselectionNR, typically 1 to 2 seconds), Treselection requires that a candidate cell maintain its superior R-criterion rank continuously for this duration. This temporal filter prevents transient radio fluctuations (shadowing, fading dips) from triggering premature cell changes.

Key Functions

  • Enforces minimum duration a neighbor must outperform serving cell
  • Eliminates rapid ping-pong transitions caused by fast Rayleigh fading
  • Scaled dynamically based on UE mobility speed (Normal, Medium, High)
Specifications
3GPP TS 38.304, TS 38.331
Interfaces
Uu

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