Indoor Positioning Using Femtocells

The ability to locate oneself indoors on a map and navigate to desired areas has a wide range of applications. GPS and macro cell tower based positioning are not very effective indoors due to poor signal quality or limited accuracy in location estimation. We propose to solve this problem by deploying an indoor network of femtocells and determining the position of a 3G mobile using the downlink and uplink signals. The measurement of signals from a group of femtocells at the mobile and the measurement of the mobile's transmitted signal at group of femtocells is used for triangulation of the mobile's position. It is shown that a combination of these methods with a cleverly designed transmission schedule involving time orthogonalization of the femtocell signals can enable accurate indoor positioning.