MAC CE TCI Indication

Technical Explanation

While RRC can configure up to 128 TCI states per BWP, the DCI field has only 3 bits (8 states). The TCI States Activation/Deactivation MAC CE selects up to 8 candidate TCI states from the RRC pool and maps them to the DCI codepoints, enabling rapid sub-millisecond beam switching.

Key Functions

• Selects up to 8 active TCI states from a broader RRC pool of up to 128
• Maps selected beam states to the 3-bit DCI field
• Enables rapid beam switching across physical antenna panels