Position location scheme for low coverage areas

A network-based hybrid location scheme is proposed for the localization of mobile users at outskirts of coverage areas. Since in the case of low subscriber density areas, the number of base stations is reduced, difference time of arrival (DTOA) and angle of arrival (AOA) measurements are combined to allow acquisition of mobile location using only one BS and one LMU as fixed land references. The feasibility of the proposed methodology, based on maximum likelihood estimation, is examined analytically and via simulation for a variety of propagation scenarios. Results show that the proposed methodology can be applied for a wide range of cell sizes and noise environments.