System and method of handling bandwidth part inactivity timer

A method of a base station, the method comprising:

• transmitting, to a user equipment (UE), first information of a timer associated with bandwidth part (BWP) inactivity;
• and
• transmitting, to the UE, physical downlink control channel (PDCCH) on an active BWP associated with a serving cell,
• wherein the timer is started or re-started in response to identifying that there is no ongoing random access procedure associated with the serving cell.

A user equipment (UE) in a wireless communication system, the UE comprising:

• a transceiver;
• and
• at least one processor coupled to the transceiver, the processor configured to:
• control the transceiver to receive, from a base station, first information of a timer associated with bandwidth part (BWP) inactivity;
• control the transceiver to receive, from the base station, physical downlink control channel (PDCCH) on an active BWP associated with a serving cell;
• identify whether there is ongoing random access procedure associated with the serving cell;
• and
• start or re-start the timer in response to identifying that there is no ongoing random access procedure associated with the serving cell.

A base station in a wireless communication system, the base station comprising:

• a transceiver;
• and
• at least one processor coupled to the transceiver, the processor configured to control the transceiver to:
• transmit, to a user equipment (UE), first information of a timer associated with bandwidth part (BWP) inactivity;
• and
• transmit, to the UE, physical downlink control channel (PDCCH) on an active BWP associated with a serving cell,
• wherein the timer is started or re-started in response to identifying that there is no ongoing random access procedure associated with the serving cell.