US 9,756,589 B2 · Macro-network location determination, local-oscillator stabilization, and frame-start synchronization based on nearby FM radio signals

Abstract

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.

Claims19

Dependent claims

A method for stabilizing a local oscillator of a first base station in a macro network, the method comprising:

the first base station in the macro network receiving a frequency modulated (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 the local oscillator;
the first base station phase-locking the local oscillator to the FM radio signal;
the first base station receiving, over a period of time, a plurality of phase-error indications that are each generated by a network operations center, wherein each received phase-error indication indicates phase drift of the FM radio signal;
and
the first base station using at least one of the received phase-error indications to adjust the phase of the local oscillator in order to account for phase drift of the FM radio signal indicated by the at least one received phase-error indication.

2 more elements

A base station in a macro network, wherein the base station comprises:

a macro-network communication interface;
a frequency modulated (FM) receiver configured to receive one or more FM radio signals;
a local oscillator;
and
program instructions stored in a non-transitory computer readable medium and executable by at least one processor to:
(a) tune the FM receiver to a first FM radio signal that is broadcast by an FM station, wherein the base station and the FM station are both located in a given telecommunications market;
(b) phase-lock the local oscillator to the first FM radio signal;
(c) receive, over a period of time, a plurality of phase-error indications that are each generated by a network operations center, wherein each received phase-error indication indicates phase drift of the first FM radio signal;
and
(d) use at least one of the received phase-error indications to adjust the phase of the local oscillator in order to account for phase drift of the first FM radio signal indicated by the at least one received phase-error indication.

7 more elements

Dependencies are inferred from the claim text.

Macro-network location determination, local-oscillator stabilization, and frame-start synchronization based on nearby FM radio signals

Life of this patent

Macro-network location determination, local-oscillator stabilization, and frame-start synchronization based on nearby FM radio signals

Life of this patent

Abstract

Claims19