DLE state is characterized as follows: UE is known in EPC and has an assigned IP address; UE is not known in E-UTRAN/eNB; User terminal's location is known at Tracking Area level; RRC_CONNECTED RRC_IDLE Connected to the Serving Cell Monitoring PCH Based on the Dormant Active DRX Cycle (OUT_OF_SYNC) (IN_SYNC) DL Reception Possible DL/UL Reception/ No UL Transmission Transmission Possible FIGURE 6-27 3GPP LTE UE states and sub-states [12] 6.13 3GPP LTE radio resource control functions Unicast data transfer with UE is not possible; UE can be reached through paging in Tracking Areas controlled by EPC; UE-based cell-selection and Tracking Area update provided to EPC. RRC_CONNECTED is a state where transfer of unicast data to/from UE is performed and the UE may be configured with a UE specific DRX or Discontinuous Transmission (DTX). The UE monitors control channels associated with the shared data channel to determine if data is scheduled for it, provides channel quality and feedback information, performs neighboring cell measurements and measurement reporting, and acquires system information. One or multiple IP addresses are assigned to the UE, as well as a temporary identifier called Cell Radio Network Temporary Identifier (C-RNTI) that is used for signaling purposes between the UE and the network. In brief, the RRC_CONNECTED state is characterized as follows: UE is known in EPC and E-UTRAN/eNB, i.e., UE context is stored in eNB; UE location is known at cell level; Unicast data transfer with UE is possible; DRX is supported for power saving (in Dormant sub-state); Mobility is controlled by the network. According to references [12] and [15], the RRC_CONNECTED state can be further implicitly divided into sub-states: (1) Dormant (OUT_OF_SYNC), where the UE may receive DL transmission but cannot transmit in the UL, if the UE is not synchronized to the network; and (2) Active (IN_SYNC), where a network-synchronized UE can send and receive in the UL and DL, respectively. These sub- states have not been further specified in