The combination of location positioning technologies such as GPS and initiatives like the US Federal Communications Commission's E911 telecommunication has generated a lot of interest in applications and services that are a function of a user's location, referred to as location-based services (LBS). A multitude of applications and services would also benefit from indoor (in-building) positioning and navigation. However, despite GPS technology and the positioning capabilities of cellular networks such as GSM, millions of square meters of indoor space are out of reach of these systems. Fortunately, over the past decade, advances in location positioning technology have made it possible to locate objects indoors. These alternative technologies are now being introduced to the market enabling many kinds of indoor LBS applications. The argument/exploration of this paper is that in order for indoor LBS to become widely used, there is a need for the infrastructure investment.
More info here.