Next Generation Wireless Applications: Creating Mobile Applications in a Web 2.0 and Mobile 2.0 World, 2nd Edition

13.5 INTERFACING LBS APPLICATIONS WITH THE CELLULAR NETWORK

The remaining issue is how to get the location information into our location-enabled application. We have previously discussed accessing location information via Web Services APIs like OSA of 3G, which is an implementation of Parlay (Parlay X being the Web Services presentation).

Figure 13.18 Location-based services architecture in the cellular network.

Figure 13.18 shows the basic architecture of the location infrastructure in a cellular network. Just as we saw that clusters of adjacent cells formed routing areas for SGSN data concentration, there are similar routing areas of the network, each served by a SMLC. This is responsible for gathering the actual location measurements from devices and for the presentation of this information in a useful and agreeable form to the higher entities in the network, including, eventually, our location-enabled applications, J2EE or not.

The information from the SMLCs is concentrated into a Gateway Mobile Location Centre (GMLC), which is a secure boundary point for external entities to attain mobile location information about a particular subscriber. Apart from providing the main interface with the outside world, the GMLC makes location information available in terms of subscriber ID and not device ID; hence, why it has a relationship with the Home Location Register (HLR), which stores ...