Method and apparatus for efficient network scanning

1. A method of frequency band scanning of multiple supported bands to obtain service for a mobile device, the supported band including first bands from a first network frequency plan and second bands from a second network frequency plan, the first bands being different from the second bands, the method comprising:

scanning, from the mobile device, to identify which of the first bands and second bands are active, wherein a band is active if the mobile device could obtain wireless services on that band;

establishing a connection on one of the bands identified as being active;

storing, in memory on the mobile device, a list of the bands identified as being active during the scanning, including the one band on which the connection was established and a band on which the mobile device did not obtain wireless services;

in response to a loss of coverage on the one band, selecting another band from the list of bands, irrespective of the frequency plan to which said another band belongs; and

scanning the selected band, and

wherein the one band is a member of said first network frequency plan and wherein the selected band is a member of said second network frequency plan, and wherein said list excludes another band within said first network frequency plan.

2. The method claimed in claim 1 , wherein said one band is a member of said first network frequency plan and wherein said selected band to be scanned is a member of said second network frequency plan.

3. The method claimed in claim 2 , wherein said list excludes another band within said first network frequency plan.

4. The method claimed in claim 2 , wherein said first network frequency plan comprises at least two possibly co-existing frequency bands, and wherein said second network frequency plan comprises at least two other possibly co-existing frequency bands, and wherein said at least two possibly co-existing frequency bands are mutually exclusive from said at least two other possibly co-existing frequency bands.

5. The method claimed in claim 4 , wherein said at least two possibly co-existing frequency bands comprise a national frequency range allocation for wireless communications adopted by a first country, and wherein said at least two other possibly co-existing frequency bands comprise a different national frequency range allocation for wireless communication adopted by another country different from the first country.

6. The method claimed in claim 5 , wherein said at least two possibly co-existing frequency bands comprise a 850 MHz band and a 1900 MHz band, and wherein said at least two other possibly co-existing frequency bands comprise a 900 MHz band and a 1900 MHz band.

7. The method claimed in claim 1 , further comprising re-establishing service using said selected band.

8. The method claimed in claim 1 , further comprising determining that said selected band is unavailable for service based on said scanning said selected band, and updating said list to remove said selected band.

9. The method claimed in claim 8 , further comprising, after said updating, determining that said list contains no additional bands, determining that a frequency band supported by the device has not been scanned and, in response, scanning said frequency band supported by the device.

10. A mobile electronic device, comprising:

a communications subsystem for frequency band scanning of multiple supported bands to obtain service for a mobile device, the supported band including first bands from a first network frequency plan and second bands from a second network frequency plan, the first bands being different from the second bands;

memory; and

a processor connected to said memory and to said communications subsystem for controlling operation of said communications subsystem, wherein the processor is configured to

scan, at the mobile device, to identify which of the first bands and second bands are active, wherein a band is active if the mobile device could obtain wireless services on that band,

establish a connection on one of the bands identified as being active,

store in memory a list of the bands identified as being active during the scanning,

including the one band on which the connection was established and a band on which the mobile device did not obtain wireless service,

in response to a loss of coverage on the one band, select another band from the list of bands, irrespective of the frequency plan to which the another band belongs, and

scan the selected band, and

wherein the one band is a member of said first network frequency plan and wherein the selected band is a member of said second network frequency plan, and wherein said list excludes another band within said first network frequency plan.

11. The mobile electronic device claimed in claim 10 , wherein the one band is a member of said first network frequency plan and wherein the selected band to be scanned is a member of said second network frequency plan.

12. The mobile electronic device claimed in claim 11 , wherein said list excludes another band within said first network frequency plan.

13. The mobile electronic device claimed in claim 11 , wherein said first network frequency plan comprises at least two possibly co-existing frequency bands, and wherein said second network frequency plan comprises at least two other possibly co-existing frequency bands, and wherein said at least two possibly co-existing frequency bands are mutually exclusive from said at least two other possibly co-existing frequency bands.

14. The mobile electronic device claimed in claim 13 , wherein said at least two possibly co-existing frequency bands comprise a national frequency range allocation for wireless communications adopted by a first country, and wherein said at least two other possibly co-existing frequency bands comprise a different national frequency range allocation for wireless communication adopted by another country different from the first country.

15. The mobile electronic device claimed in claim 14 , wherein said at least two possibly co-existing frequency bands comprise a 850 MHz band and a 1900 MHz band, and wherein said at least two other possibly co-existing frequency bands comprise a 900 MHz band and a 1900 MHz band.

16. The mobile electronic device claimed in claim 10 , wherein said processor is configured to re-establish service using said selected band.

17. The mobile electronic device claimed in claim 10 , wherein said processor is configured to determine that said selected band is unavailable for service based on said scan of said selected band, and to update said list to remove said selected band.

18. The mobile electronic device claimed in claim 17 , wherein said processor is configured to determine that said list contains no additional bands after said update, to determine that a frequency band supported by the device has not been scanned and, in response, to scan said frequency band supported by the device.

19. A mobile electronic device, comprising:

a communications subsystem for frequency band scanning of multiple supported bands to obtain service for a mobile device, the supported band including first bands from a first network frequency plan and second bands from a second network frequency plan, the first bands being different from the second bands;

memory; and

a network locator component configured to

identify, at the mobile device, which of the first bands and second bands are active,

wherein a band is active if the mobile device could obtain wireless services on that band,

instruct the communications system to establish a connection on one of the bands identified as being active,

store in memory a list of the bands identified as being active including the one band on which the connection was established and a band on which the mobile device did not obtain wireless service,

select another band from the list of bands, irrespective of the frequency plan to which the another band belongs, in response to a loss of coverage on the one band, and

scan the selected band, and

wherein the one band is a member of said first network frequency plan and wherein the selected band is a member of said second network frequency plan, and wherein said list excludes another band within said first network frequency plan.