Location Based Services (LBS) is a billion dollar business. The technology enables you to develop new products and services that are only limited by the imagination.

Where are you? Most people ask this question when they telephone somebody on a mobile telephone. It is most certainly an indication that we forgot something when we designed the first generations of mobile communication systems.

We had the geographical location built into wireline telephony from the beginning. You know where you are calling but not always who will be answering. Mobile phones have become a rather personal asset and have turned this upside down - you know who you are calling but not where they are located. Somewhere along the way we lost the location!

There is no doubt that there is a tremendous value in knowing the geographical location of a mobile phone. Almost any service that involves information about mobile objects can benefit from knowing the location of a mobile phone. May it be a person wearing a personal mobile phone or a machine with an attached module (mobile phone without display and buttons)?

New innovative services never thought of before suddenly become possible. Since the ability to locate phones is brand new, we have not yet seen all possible killer application.

In a Location Based Service the application need to interact with the GSM and/or WCDMA network to get the mobile position (x/y-coordinates), but also for other purposes (messaging etc.). The interaction takes place via the so called Middleware which serves purposes such as to provide a network independent, unified interface towards the applications. Ericsson provides currently three alternative Middleware options which can be used by the developer:

• Ericsson’s Telecom Web Services SDK, which uses location APIs defined in the Parlay X standard                  
• Mobilaris middleware with its own SDK                  
• Reach-U middleware with its own SDK

Whether to use the SDK provided by Ericsson,  Mobilaris or Reach-U depends on which operator’s network you want your service to interact with. In either case you need to contact Ericsson (for Telecom Web Services), Mobilaris or Reach-U to get detailed information about the operating conditions of your target operator.

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Figure 1. Positioning in GSM and WCDMA networks. 

Mobile Positioning System (MPS) is the name of Ericsson's positioning platform for Location Based Services. MPS is built up of standardized network nodes and interfaces; the Gateway Mobile Location Centre (GMLC), the Serving Mobile Location Centre (SMLC) and various supporting functions (software extensions) in the operator's mobile network, see figure 1. MPS supports both the SS7-based control plane and the IP-based Secure User Plane Location (SUPL) architectures.

A Mobile Positioning System determines the geographical position of mobile subscribers. By combining positional mechanisms with location specific information truly customized personal communication services can be offered through the mobile phone or other mobile devices.

An LBS application provided by the operator or by a service provider on the Internet requests GMLC for the position of a mobile phone. GMLC performs, among other things, an authorization check on the request. The authorized request is delivered to SMLC via the mobile network (GSM or WCDMA). SMLC collects position information from the network and calculates the coordinates to be used by the application. SMPC delivers the coordinates to GMLC which then creates a position response that is replied to the LBS application.

MPS enables an operator a flexible and powerful way of providing new revenue generating services such as information services, games, friend finder and fleet/resource management to his customers as well as fulfilling legal requirements on locating emergency calls. Provision of location-based services is a way for the operator to differentiate on the market, reduce churn and increase revenues. Combining the end-user's location with MMS and Java download enables very compelling services.

MPS supports the cell-based positioning methods Cell Global Identity with Timing Advance (CGI/TA), Enhanced CGI (E-CGI), Cell ID and Round Trip Time (RTT– similar to TA) for WCDMA and Any Time Interrogation (ATI). These methods can be used by all legacy GSM and WCDMA phones. In addition MPS supports high accuracy positioning for Assisted GPS (A-GPS) enabled phones. All these methods are explained in more detail in this flash film

MPS supports Spatial Triggers, a function that notifies applications automatically when a mobile phone enters or leaves a certain pre-defined location, or when two mobile phones approach each other. Spatial Triggers is explained in more detail in this flash film

MPS supports the standardized Mobile Location Protocol (MLP), which is the interface between the LBS Client and GMLC.