This document provides an overview of mobile technologies and location-based services (LBS) in 3 sentences: It describes the basic components of a GSM network including the BTS, BSC, MSC, HLR, VLR and introduces LBS elements like the LMU, SMLC, and GMLC. It also explains some locationing technologies used in LBS like GPS, A-GPS, and network-based methods. Finally, it mentions some common LBS applications such as emergency services, traffic/weather alerts, and location-sensitive advertising.