GNSS-assisted cellular network selection
A method of selecting a cellular network entails determining a current location using a Global Navigation Satellite System (GNSS) receiver in a mobile device, prioritizing bands based on the current location to create a set of prioritized bands, and searching the set of prioritized bands for the cellular network. This method expedites selection of the cellular network when a mobile device is powered on or when its cellular radiofrequency transceiver is activated.
1. A method of selecting a cellular network, the method comprising:
determining a current location using a Global Navigation Satellite System (GNSS) receiver in a mobile device, comprising obtaining, using the GNSS receiver, a partial position fix providing a coarse approximation for the current location based on Doppler frequency shift measurements, ephemeris data already stored in a memory of the mobile device and a received time tag within a received GNSS signal;
prioritizing cellular network frequency bands based on the current location to define a band priority; and
selecting the cellular network based on the band priority.
2. The method as claimed in claim 1 wherein the GNSS receiver is activated in response to activating a cellular radiofrequency transceiver.
3. The method as claimed in claim 1 comprising searching a PLMN list on activating a cellular radiofrequency transceiver and interrupting the searching of the PLMN list only when the mobile device has determined the current location and the bands have been prioritized.
4. A non-transitory computer-readable medium comprising instructions in code which when loaded into a memory and executed by a processor of a mobile device cause the mobile device to:
determine a current location using a Global Navigation Satellite System (GNSS) receiver in a mobile device, comprising obtaining, using the GNSS receiver, a partial position fix providing a coarse approximation for the current location based on Doppler frequency shift measurements, ephemeris data already stored in a memory of the mobile device and as received time tag within a received GNSS signal;
prioritize cellular network frequency bands based on the current location to define a band priority; and
select a cellular network based on the band priority.
5. The computer-readable medium as claimed in claim 4 comprising code to activate the GNSS receiver in response to activating a cellular radiofrequency transceiver.
6. The computer-readable medium as claimed in claim 4 comprising code that causes the mobile device to search a PLMN list on activating a cellular radiofrequency transceiver and interrupt a search of the PLMN list only when the mobile device has determined the current location and the bands have been prioritized.
7. A mobile device comprising:
a cellular radiofrequency transceiver;
a Global Navigation Satellite System (GNSS) receiver to determine a current location of the mobile device, comprising obtaining a partial position fix providing a coarse approximation for the current location, using the GNSS receiver, based on Doppler frequency shift measurements, ephemeris data already stored in a memory of the mobile device and a received time tag within a received GNSS signal; and
a processor configured to prioritize cellular network frequency bands based on the current location to define a band priority and to select a cellular network based on the band priority.
8. The mobile device as claimed in claim 7 wherein the processor activates the GNSS receiver in response to activating the cellular radiofrequency transceiver.
9. The mobile device as claimed in claim 7 wherein the processor is configured to search a PLMN list on activating a cellular radiofrequency transceiver and interrupt a search of the PLMN list only when the mobile device has determined the current location and the bands have been prioritized.