Locating a mobile unit in a wireless time division multiple access system

摘要

A method for locating a mobile unit without synchronizing base-stations is provided. A triangulation scheme where distances between a plurality of base-stations and a mobile unit (herein termed mobile) are calculated by measuring at least three round-trip-delay-values wherein each round-trip-delay-value corresponds to transmission of a downlink signal from each base-station to the mobile unit and transmission of an uplink signal, in response to the downlink signal, from the mobile unit to each base-station is described. It is a low-cost solution without requiring the participating base-stations to be accurately synchronized in time and with the added advantages of utilizing a known downlink signal and a known uplink signal in determining the position of the mobile. <IMAGE>