Reference selection for handover with PScell change or addition

A baseband processor, comprising:

• a memory configured to store instructions;
• and
• a processor, coupled to the memory and when executing the instructions, configured to:
• send radio resource control (RRC) information elements including a measurement object having a synchronization signal/physical broadcast channel (SS/PBCH) block measurement time configuration (SMTC);
• send a handover command for a handover procedure including changing a source Primary Secondary Cell (PSCell) to a target PSCell or adding the target PSCell, wherein a source primary cell (PCell) is used for reference timing of the SMTC, in response to the measurement object being configured by the source PCell on the same frequency and subcarrier spacing of the target PSCell;
• and
• perform a measurement for the target PSCell in accordance with the SMTC,
• wherein the SMTC is assigned a fixed default periodicity, in response to the SMTC of the measurement object being not configured on the same frequency and subcarrier spacing of the target PSCell.

A method, comprising:

• receiving a radio resource control (RRC) information element including a measurement object having a synchronization signal/physical broadcast channel (SS/PBCH) block measurement time configuration (SMTC);
• receiving a handover command including changing a source Primary Secondary Cell (PSCell) to a target PSCell or adding the target PSCell, wherein the source PSCell is used for reference timing of the SMTC, in response to the measurement object being configured by the source PSCell on the same frequency and subcarrier spacing of the target PSCell;
• and
• performing a measurement for the target PSCell in accordance with the SMTC,
• wherein the SMTC is assigned a fixed default periodicity, in response to the SMTC of the measurement object being not configured on the same frequency and subcarrier spacing of the target PSCell.