Gateway Mobile Location Centre (GMLC)

Creativity Software’s GMLC solution can interconnect with third party SMLCs or can be delivered as part of a complete turnkey solution. Our GMLC offers a range of deployment options, supports connectivity to the NSS via Lg and Lh interfaces or alternatively make use of the MAP ATI function. For IN environments, Push Mode location updates can be supported.

GMLC – How it works

Privacy is a critical issue in location based services. The Creativity Software GMLC performs authentication and authorisation checks in location requests received from the LCS to ensure privacy and adherence to permission policies.

The GMLC provides the interface to the LCS client which may be positioned external to the network e.g. 3rd party VAS application. The GMLC receives individual requests to locate and report back the geographic position of a user mobile. Such requests are in general permission-based reports – i.e. the particular mobile user has granted approval for his/her location to be made available. At the same time, checks are made to confirm that the LCS client is authorized to make such a request and ensure the UE (User Equipment) is able to support LCS enquires.

The GMLC must first determine which Serving Mobile Switching Centre (MSC) is managing the UE at the time the LCS request is made. To do this, it first identifies the MSC involved by making a request to the HLR. The HLR returns this information and a message is sent to the appropriate BSS via the MSC. The BSS determines the serving Cell ID and if available the timing and signal strengths from this and neighbouring cells.

This combined information is routed to the SMLC / SAS / E-SMLC where the calculation of geographic position estimation is carried out. The result is passed back to the MSC via the radio sub system and then to the GMLC for delivery to the LCS client (according to the 3GPP standards, there is no direct connection between the SMLC/SAS/E-SMLC and the GMLC – the location is always reported back to the MSC that has initiated the location request).
The GMLC is based on industry-standard SS7 protocol stacks, supporting SIGTRAN interfaces for IP connectivity and TDM transport in legacy environments. Creativity Software’s GMLC can interconnect with third party SMLCs, or both can be provided as part of a turnkey solution. Creativity Software’s GMLC solution can also be configured as a fully standards-compliant MPC for CDMA networks.
The interface provided complies with OMA MLP V3.2 and V3.1. Priority levels are handled through the optional selection of a priority level within the request and feeding appropriate prioritised queues. All the following messages flows are supported as per OMA:

  • SLIS (Standard Location Immediate Service)
  • ELIS (Emergency Immediate Service)
  • TLRS (triggered location reporting service)

If available, following subscriber information can be provided to the LCS-Client in addition to location response:

  • Subscriber state
  • Age of location
  • IMSI
  • IMEI
  • VLR address

Our GMLC can interface with any HLR/MSC/SGSN that supports 3GPP 29.002.
According to the 3GPP LCS architecture, the interface between GMLC and HLR is known as the Lh interface, and the interface between GMLC and MSC/SGSN is known as the Lg interface. The GMLC uses the Lh interface to obtain routing information of a target terminal. It uses the Lg interface to request the positioning information of a target terminal from the radio network via the core network.

The GMLC supports the following MAP LCS standard messages:

  • MAP-SendRoutingInfoforLCS (SRI-LCS)
  • MAP-ProvideSubscriberLocation (PSL)
  • MAP-AnyTimeInterrogation(ATI)
  • MAP-SubscriberLocationReport (SRI)
  • MAP-SendRoutingInfoForSM (SRI-SM)
  • MAP-ProvideSubscriberInformation (PSI)
  • MAP-SubscriberLocationReport (SLR)