Macro-Network Location Determination, Local-Oscillator Stabilization, And Frame-Start Synchronization Based On Nearby FM Radio Signals

摘要

Exemplary methods and systems may generally be implemented to allow a macro-network base station without access to a GPS reference signal to provide some or all of the functionality for which existing macro-network base stations typically rely on GPS. In a first aspect, an exemplary macro-network base station may determine its location using a location-determination technique that is based upon the angles of arrival of FM radio signals from nearby FM stations. In a second aspect, an exemplary macro-network base station may stabilize its local oscillator by phase-locking its local oscillator to an FM radio signal, and periodically adjusting its local oscillator to account for phase drift of the FM radio signal. And in a third aspect, an exemplary macro-network base station may synchronize its frame-start timing with a nearby base station using a frame-start timing signal that the base station has synchronized to frame transmissions from the nearby base station during a setup routine.

主权项

1. A method for stabilizing a local oscillator of a first base station in a macro network, the method comprising:
a first base station in a macro network receiving an FM radio signal from an FM station, wherein the first base station and the FM station are both located in a given telecommunications market, and wherein the first base station comprises a local oscillator; the first base station phase-locking the local oscillator to the FM radio signal; the first base station periodically receiving a phase-error indication, wherein each received phase-error indication indicates phase drift of the FM radio signal; and the first base station using each received phase-error indication to adjust the phase of the local oscillator in order to account for phase drift of the FM radio signal.