The invention performs long term evolution (LTE) tracking area updates (TAUs), and tracking area code (TAC) and public land mobile network identification (PLMN-ID) assisted optimized wireless transmit/receive unit (WTRU) cell reselection. An evolved Node-B broadcasts system information including at least one system information block (SIB) based at least in part on an enhanced universal terrestrial radio access network (E-UTRAN) parameter response message sent by an evolved packet core (EPC) network. A WTRU generates a new TAC, which represents a tracking area identification (TA-ID) of a new cell, based on the system information, and compares the new TAC to an existing TAC, which represents a TA-ID of a previous cell. The WTRU transmits to the EPC network a TAU request message including the TA-ID of the new cell. The EPC network sends either a TAU accept message or a TAU reject message to the WTRU.