A method of uplink shaping and extending UE in RRC Idle Mode is proposed. The UE processes a data packet to be sent to the network. The data packet is associated with a traffic type. If the data packet belongs to a normal traffic type, then the UE enters RRC Connected mode and thereby transmitting the data packet to the network. If the data packet belongs to a background traffic type, then the UE buffers the data packet and the UE is prohibited from entering RRC Connected mode until a triggering condition is satisfied for uplink transmission. The proposed mechanism achieves power saving by reducing the activity of uplink transmission. In addition, the proposed mechanism also reduces signaling overhead to enhance network efficiency.