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How to use GMLC: cases, ideas, challenges

In this article we will talk about GMLC that is used for precise mobile positioning, which means that it initiates certain actions on the network to obtain the subscriber's real-time location.

What is the Gateway Mobile Location Centre (GMLC)?

A Gateway Mobile Location Centre is a platform that locates any mobile device at any time without the need to connect to the Internet or download an application, as long as the mobile device is connected to its mobile operator. Obtaining the location information of mobile devices enables location-based services (LBS), including vehicle tracking, location-based advertising, emergency services, and other geolocation services.

In the case of emergency calls, the Location Retrieval Function (LRF), combined with GMLC, retrieves the location information of the user who initiated the emergency session. The Emergency Call Session Control Function (E-CSCF) obtains a dedicated originating address from the Route Determination Function (RDF) to send an emergency request to a Public Safety Response Point (PSAP).

SMLC/SAS/e-SMLC/LMF, on the other hand, is a network element in the LCS network of the PLMN. It manages the overall coordination, calculation, and planning of the resources needed to determine the geographic location of the MS in the network. GMLCs can be integrated with Serving Mobile Location Centers (SMLCs) to greatly improve the accuracy of location reporting.

How does GMLC work?

The GMLC may request routing information from the Home Location Register (HLR) or Home Subscriber Server (HSS). After registration authorization, it sends positioning requests to either the Visited Mobile Switching Centre (VMSC), the SGSN serving GPRS Support Node (SGSN), or the Mobile Switching Centre (MSC) server and obtains the final location estimates from the respective entity.

The GMLC communicates with Location Services (LCS) clients that may be outside the network, such as a third-party value-added service (VAS) application. Individual requests to locate and report a user's mobile phone are accepted by the GMLC. At the same time, checks are performed to ensure that the LCS client is allowed to make such a request and that the UE (user equipment) can support LCS requests. GMLC is always installed on at least two servers, guaranteeing the system's continuous operation. It is also linked to the operator's monitoring system to ensure the smooth running of maintenance. GMLC provides the operator with detailed information on all system events, making detecting and resolving problems much easier.

GMLC features


To ensure confidentiality and compliance with permission requirements, the GMLC solution typically performs validation and approval verification on all location requests from the LCS. The GMLC must determine the serving node (MSC, MME, AMF) responsible for the UE at the time of the LCS request. To do this, in standard call flows, the GMLC sends a request to the HLR/HSS/UDM to identify the current serving node. The HLR/HSS/UDM returns this data, and the GMLC sends a message to the appropriate serving node to obtain the subscriber's location information.

Precise mobile positioning

GMLC is used for precise mobile positioning, which means that it initiates certain actions on the network to obtain the subscriber's real-time location. The GMLC can be connected to additional precise positioning components in the network to improve positioning accuracy. They are named differently depending on the generation of the network - SMLC (2G), SAS (3G), E-SMLC (4G), LMF (5G) - and control the request for a data set to the UE (user equipment) and the calculation of an accurate position estimate with it.

GMLC: Use Cases

Whether you are, for example, a rail operator who wants to provide real-time information to their customers, or a retailer who wants to provide contextual and location-based offers to their customers, GMLC can help you. The gateway's mobile location centre can open up many new opportunities for your business, helping you stay relevant and innovative in an ever-increasing competition. Let's talk more about where else GMCL can come in handy.

Telecommunication operators

Telecommunication operators can offer various location-based services (LBS) and improve the quality of service for their users to a new level.

Emergency Services

Mobile location saves lives 24/7 without breaks and weekends. The GMLS solution allows mobile operators to locate E112/911 mobile calls and provide this critical information to public service access points (emergency alert centers) that process the calls.

Location-based commercial services

The MLC solution may provide open APIs used by third-party applications to exploit valuable location information. At the same time, the privacy of the person to be found is fully protected, allowing him to control which applications can find him and/or never reveal the real identity of the end user to the application.

Operator's internal services

The mobile network operator may also use the MLC solution for internal purposes, such as improving customer support and device location when the police/district attorney requests.

Using GMCL at full throttle: ideas

Here we collected top ideas on how to use GMLC regardless of your industry to improve customers' experience.

  • Tracking - provides real-time tracking;
  • Courier Tracking - provides location information to third-party companies;
  • Emergency Service - provide alert status, speed up emergency response time;
  • Location by complaint - track status in case of threat or complaint;
  • Location-Based Advertising - enable location-based marketing for users;
  • Promotion to the user in a specific location - provide the user with promotions based on their location;
  • Different USSD menus in different locations - provides real-time menu-based applications in different locations;
  • Local Product Subscription - provides the user with a product subscription based on their location, such as city;
  • Low balance - send the location of the nearest recharge points.

Whatever your industry, GMLC is a worthwhile investment!

Mobius GMLC

Mobius GMLC supports location-based services designed for VAS vendors and consumers. Using our gateway, you can connect to any Mobile Network Operator or Mobile Virtual Network Operator core network over SS7 MAP. Also, it enables location-based services in web, IOS, and Android apps via geolocation API. In addition, you can significantly reduce CAPEX and OPEX costs due to flexible adaptation to all telecom service providers' needs. Fill out the feedback form, and our competent specialist will contact you shortly.

Aug 18,2022 ● 8 min read

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