4. Functional Behavior

In this section, we cover the different functional scenarios and behaviors that the GMLC and overall LCS system support. This includes types of location requests, privacy handling, accuracy/QoS considerations, roaming cases, and emergency services handling.

4.1 Types of Location Requests (Immediate vs Deferred, MT-LR vs MO-LR vs NI-LR)

Immediate Location Request: This is the most common type, where the requesting client wants the target’s location now (or as soon as possible). An immediate location request can be initiated by an external client (MT-LR – Mobile Terminated Location Request, since it’s terminating at the UE) or by the network itself (NI-LR – Network Induced, e.g. for an emergency call) or even by the UE (MO-LR – Mobile Originated, where the UE asks to report its own location to some server, though MO-LR is less common in 3GPP except for emergency). In any case, an immediate request implies a single location fix (though it could be one fix with multiple attempts or methods to meet QoS). According to [TS 23.273], “With an immediate location request, an LCS client or AF sends or instigates a location request for a target UE and expects to receive a response containing location information… within a short time period which may be specified using QoS.”. Essentially, the GMLC will attempt to get the current location right away. If the UE is available and responds, the client gets one location result (or possibly one per access network if dual-connected). Immediate requests are the default mode for on-demand queries.