LTE, or Long Term Evolution (also known sometimes as 3.9G) is a name for research and development, involving the Third Generation Partnership Project (3GPP), to identify technologies and capabilities that can improve systems such as the Universal Mobile Telecommunications System (UMTS). It is known that a user equipment (UE) will be in an idle state when it is not in a connected state. Once in the connected state, there are a number of possible states that the UE can be in, and it is often possible to transition between those states. LTE is concerned with both the idle state as well as the connected states.
A Radio Link Identity (RLID) is similar to a Cell Radio Network Temporary Identifier (C-RNTI) in the Universal Terrestrial Radio Access Network (UTRAN). In the LTE, a user equipment (UE) in idle mode does not automatically have a cell-specific RLID which may be needed by the network (NW) so as to allocate resources for sending and/or receiving data. Thus, when the UE attempts to perform some procedure in idle mode, such as attempting a Location Area Update (LAU), the UE often needs to receive the RLID in order to be able to communicate with the NW. Obtaining the RLID sometimes requires quite a lot of signaling, and it would be desirable to reduce or eliminate that amount of signaling.
Location updating is a procedure used to ensure that the network knows the location of the UE when the UE is in an idle state. In this state, the UE does not have an active signaling connection to the network, but nevertheless the network is responsible for tracking the location of the UE. For example, the UE can decode a broadcasted location area identifier of the UE's current cell, and if the location area identifier changes, due to movement of the UE, then the UE can perform an LAU to notify the network. One possible purpose for the network to have this kind of location awareness is to control the amount of paging required by the network in order to reach a specific UE; the network can merely page those specific cells that are part of the location area where the UE is located.
In former systems, such as the Global System for Mobile (GSM) Communications Enhanced Data Rates for Global Evolution (EDGE) Radio Access Network (GERAN) and such as UTRAN, the UE has needed to establish a dedicated connection in order to perform the location area update (LAU). Unfortunately, that has entailed a relatively inefficient use of resources.