Method and apparatus for cell update while in an enhanced Cell—FACH state

A wireless transmit/receive unit (WTRU) for performing a cell update while in a Cell_FACH state, the WTRU comprising:

• a controller configured to:
• detect a cell update triggering event while receiving a high speed downlink packet access (HSDPA) transmission in a Cell_DCH state using a dedicated high speed downlink shared channel (HS-DSCH) radio network temporary identity (H-RNTI), the cell update triggering event comprising at least one of a radio link failure or a radio link control (RLC) unrecoverable error,
• clear a radio network temporary identity (RNTI) received in a source cell,
• read system information in a target cell, and
• based on common HS-DSCH system information included in the system information, reset a high speed downlink shared channel (HS-DSCH) medium access control (MAC-ehs) entity, and enable HS-DSCH reception by setting an HS-DSCH reception variable to TRUE.

A method for performing cell reselection while in a Cell_FACH state, the method comprising:

• receiving information from a source cell that supports Cell FACH;
• selecting a target cell for the cell reselection, wherein the target cell supports Cell_FACH or fails to support Cell_FACH;
• reading system information broadcast from the target cell;
• determining, based on the system information from the target cell, whether the target cell supports Cell_FACH;
• and
• receiving information from the target cell based on whether the target cell supports Cell_FACH or fails to support Cell_FACH.

A wireless transmit/receive unit (WTRU) for performing cell update while in a Cell_FACH state, the WTRU comprising:

• a controller configured to:
• receive information from a source cell that supports Cell_FACH;
• select a target cell for cell reselection, wherein the target cell supports Cell_FACH or fails to support Cell_FACH;
• read system information broadcast from the target cell;
• determine, based on the system information from the target cell, whether the target cell supports Cell_FACH;
• and
• receive information from the target cell based on whether the target cell supports Cell_FACH or fails to support Cell_FACH.