Motorola Corporation

Motorola Solutions, Inc.

Kristi A Haverkamp

Jose E Korneluk

Keith M Klug

Bobby D Anderson, Ii

Charles H Segerson

Charles Burton Swope

Nereydo T Contreras

Anil N Patel

Mark A Goldberg

Atif A Meraj

A mobile communication device () and peer mobile communication devices () are capable of direct voice and data communication. The mobile communication device has a reference oscillator () which is used for generating operating frequencies, and is subject to frequency errors resulting from manufacturing tolerances, heat, and other error sources. The mobile communication device receives a frequency correction message () from a peer mobile communication device that has calibrated its reference oscillator. The frequency correction message contain offset information which is used by the mobile communication device to determine its offset () from a nominal frequency ().

Method and apparatus for providing reference frequency aiding among peers operating in a direct communication mode

A mobile communication device () outside the service area of a communications networkin need of satellite positioning assistance information to perform a location determination (). The mobile communication device receives the assistance information from a peer mobile communication device () over a direct link.

Method for providing location aiding among peers operating in a direct communication mode

A frequency management scheme for a hybrid cellular/GPS or other device generates a local clock signal for the communications portion of the device, using a crystal oscillator or other part. The oscillator output may be corrected by way of an automatic frequency control (AFC) circuit or software, to drive the frequency of that clock signal to a higher accuracy. Besides being delivered to the cellular or other communications portion of the hybrid device, the compensated clock signal may also be delivered to a comparator to measure the offset between the cellular oscillator and the GPS oscillator. The error in the cellular oscillator may be measured from the AFC operation in the cellular portion of the device. An undershoot or overshoot in the delta between the two oscillators may thus be deduced to be due to bias in the GPS oscillator, whose value may then be determined. That value may then be used to adjust Doppler search, bandwidth or other GPS receiver characteristics to achieve better time to first fix or other performance characteristics.

System and method for frequency management in a communication device having a positioning device

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Chandler, AZ, United States of America

Kristi A Haverkamp