Power efficient method for a mobile terminal to determine its location by processing only parts of the received signal

摘要

A mobile terminal that estimates its position within a cell of a serving base station in a CDMA cellular network using signals received from beacons/base stations, saves power by processing only parts of the received signals to obtain the propagation delays of the beacons' signals. The mobile terminal receives beacon signals (e.g. pilot transmissions) in specified periods and correlates the received signals with the parts of the beacons' code sequences expected in the specified periods, i.e. with the portions (chip indexes) of the scrambling codes expected to traverse the cell during the specified periods. The mobile terminal can then obtain the propagation delays of the beacons' signals and these can be used either by the mobile terminal or by the network, to estimate the mobile's location. The specified periods (measurement windows) and the parts of the code sequences to be used by the mobile may be signalled to it by the serving base station.