How does Location Service (LCS) work in LTE network?

In the LCS architecture, an Evolved SMLC is directly attached to the MME. The objectives of this  evolution is to support location of an IMS emergency call,  avoid impacts to a location session due to an inter-eNodeB handover, make use of an Evolved  and support Mobile originated location request (MO-LR) and mobile terminated location request MT-LR services.

Release 9 LCS solution introduces new interfaces in the EPC:

  • SLg between the GMLC and the MME
  • SLs between the E-SMLC and the MME
  • Diameter-based SLh between the HSS and the HGMLC

For details read LCS Architecture for LTE EPS and LTE UE positioning in E-UTRAN