Method and apparatus for inter radio access technology (IRAT) cell reselection

1. A method for inter radio access technology (IRAT) cell reselection, comprising:

identifying that a user equipment (UE) in an idle or a discontinuous reception (DRX) mode is camped on a cell of a first RAT, wherein the cell belongs to a public land mobile network (PLMN) identifier associated with an operator and the first RAT;

determining that neighbor information broadcast by the cell the UE is camped on does not include information of any neighbor cell of a second RAT and that the PLMN identifier associated with the cell of the first RAT belongs to a known list of PLMN identifiers;

determining that the UE is configured to enable searching for one or more frequencies of the second RAT in response to determining that the cell the UE is camped on is not broadcasting any neighbor cell of the second RAT and that the PLMN identifier associated with the cell of the first RAT belongs to the known list of PLMN identifiers;

scanning the one or more frequencies of the second RAT associated with the PLMN identifier of the operator in response to determining that the PLMN identifier has functionality enabled to search for the one or more frequencies of the second RAT, wherein the scanning for the one or more frequencies of the second RAT associated with the PLMN identifier of the operator is performed in a background at the UE; and

triggering a cell reselection to a cell of the second RAT, wherein the cell of the second RAT is associated with a frequency identified during the scanning.

2. The method of claim 1 , further comprising performing the cell reselection to the cell of the second RAT, wherein the performing further comprises:

checking whether cell reselection criteria are met;

suspending activities of the first RAT;

acquiring the cell of the second RAT; and

stopping the activities of the first RAT and transitioning the UE to the cell of the second RAT.

3. The method of claim 1 , wherein the scanning the one or more frequencies is enabled or disabled by configuring a frequency scanning parameter at the UE.

4. The method of claim 3 , wherein the enabling or disabling of the frequency scanning parameter is via a user interface at the UE.

5. The method of claim 1 , wherein the first RAT is Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Wideband-CDMA (W-CDMA) or High Speed Packet Access (HSPA), and the second RAT is long term evolution (LTE) or Worldwide Interoperability for Microwave Access (WiMAX).

6. An apparatus for inter radio access technology (IRAT) cell reselection, comprising:

means for identifying that a user equipment (UE) in an idle or a discontinuous reception (DRX) mode is camped on a cell of a first RAT, wherein the cell belongs to a public land mobile network (PLMN) identifier associated with an operator and the first RAT;

means for determining that neighbor information broadcast by the cell the UE is camped on does not include information of any neighbor cell of a second RAT and that the PLMN identifier associated with the cell of the first RAT belongs to a known list of PLMN identifiers;

means for determining that the UE is configured to enable searching for one or more frequencies of the second RAT in response to determining that the cell the UE is camped on is not broadcasting any neighbor cell of the second RAT and that the PLMN identifier associated with the cell of the first RAT belongs to the known list of PLMN identifiers;

means for scanning the one or more frequencies of the second RAT associated with the PLMN identifier of the operator in response to determining that the PLMN identifier has functionality enabled to search for the one or more frequencies of the second RAT, wherein the means for scanning includes means for performing the scanning for the one or more frequencies of the second RAT associated with the PLMN identifier of the operator in a background at the UE; and

means for triggering a cell reselection to a cell of the second RAT, wherein the cell of the second RAT is associated with a frequency identified during the scanning.

7. The apparatus of claim 6 , further comprising means for performing the cell reselection to the cell of the second RAT, wherein the means for performing further comprises:

means for checking whether cell selection reselection criteria are met;

means for suspending activities of the first RAT;

means for acquiring the cell of the second RAT; and

means for stopping the activities of the first RAT and transitioning the UE to the cell of the second RAT.

8. The apparatus of claim 6 , wherein the means for scanning the one or more frequencies includes means for enabling or disabling the scanning by configuring a frequency scanning parameter at the UE.

9. The apparatus of claim 8 , wherein the means for enabling or disabling of the frequency scanning parameter comprises a user interface at the UE.

10. The apparatus of claim 6 , wherein the first RAT is Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Wideband-CDMA (W-CDMA) or High Speed Packet Access (HSPA), and the second RAT is long term evolution (LTE) or Worldwide Interoperability for Microwave Access (WiMAX).

11. A non-transitory computer readable medium storing computer executable code for improved reselection during mode transitions, comprising:

code for identifying that a user equipment (UE) in an idle or a discontinuous reception (DRX) mode is camped on a cell of a first RAT, wherein the cell belongs to a public land mobile network (PLMN) identifier associated with an operator and the first RAT;

code for determining that neighbor information broadcast by the cell the UE is camped on does not include information of any neighbor cell of a second RAT and that the PLMN identifier associated with the cell of the first RAT belongs to a known list of PLMN identifiers;

code for determining that the UE is configured to enable searching for one or more frequencies of the second RAT in response to determining that the cell the UE is camped on is not broadcasting any neighbor cell of the second RAT and that the PLMN identifier associated with the cell of the first RAT belongs to the known list of PLMN identifiers;

code for scanning the one or more frequencies of the second RAT associated with the PLMN identifier of the operator in response to determining that the PLMN identifier has functionality enabled to search for the one or more frequencies of the second RAT, wherein the code for scanning includes code for performing the scanning for the one or more frequencies of the second RAT associated with the PLMN identifier of the operator in a background at the UE; and

code for triggering a cell reselection to a cell of the second RAT, wherein the cell of the second RAT is associated with a frequency identified during the scanning.

12. The computer readable medium of claim 11 , further comprising code for performing the cell reselection to the cell of the second RAT, wherein the code for performing further comprises:

code for checking whether cell reselection criteria are met;

code for suspending activities of the first RAT;

code for acquiring the cell of the second RAT; and

code for stopping the activities of the first RAT and transitioning the UE to the cell of the second RAT.

13. The computer readable medium of claim 11 , wherein the code for scanning the one or more frequencies includes code for enabling or disabling the scanning by configuring a frequency scanning parameter at the UE.

14. The computer readable medium of claim 13 , wherein the code for enabling or disabling of the frequency scanning parameter comprises code for enabling or disabling via a user interface at the UE.

15. The computer readable medium of claim 11 , wherein the first RAT is Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Wideband-CDMA (W-CDMA) or High Speed Packet Access (HSPA), and the second RAT is long term evolution LTE) or Worldwide Interoperability for Microwave Access (WiMAX).

16. An apparatus for inter radio access technology (IRAT) cell reselection, comprising:

a RAT identifying component to identify that a user equipment (UE) in an idle or a discontinuous reception (DRX) mode is camped on a cell of a first RAT, wherein the cell belongs to a public land mobile network (PLMN) identifier associated with an operator and the first RAT;

a neighbor broadcasting determining component to determine that neighbor information broadcast by the cell the UE is camped on does not include information of any neighbor cell of a second RAT and that the PLMN identifier associated with the cell of the first RAT belongs to a known list of PLMN identifiers;

a PLMN identifier matching component to determine that the UE is configured to enable searching for one or more frequencies of the second RAT in response to determining that the cell the UE is camped on is not broadcasting any neighbor cell of the second RAT and that the PLMN identifier associated with the cell of the first RAT belongs to the known list of PLMN identifiers;

a frequency scanning component to scan the one or more frequencies of the second RAT associated with the PLMN identifier of the operator in response to the determination that the PLMN identifier has functionality enabled to search for the one or more frequencies of the second RAT, wherein the frequency scanning component is configured to perform the scan for the one or more frequencies of the second RAT associated with the PLMN identifier of the operator in a background at the UE; and

a cell reselection component to trigger a cell reselection to a cell of the second RAT, wherein the cell of the second RAT is associated with a frequency identified during the scanning.

17. The apparatus of claim 16 , wherein cell reselection component is further configured to perform the cell reselection to the cell of the second RAT, and wherein the cell reselection component is further configured to:

check whether cell selection reselection criteria are met;

suspend activities of the first RAT;

acquire the cell of the second RAT; and

stop the activities of the first RAT and transition the UE to the cell of the second RAT.

18. The apparatus of claim 16 , wherein the frequency scanning component is further configured to enable or disable scanning the one or more frequencies by further configuring a frequency scanning parameter at the UE.

19. The apparatus of claim 18 , wherein the frequency scanning component is further configured to receive the frequency scanning parameter via a user interface at the UE.

20. The apparatus of claim 16 , wherein the first RAT is Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Wideband-CDMA (W-CDMA) or High Speed Packet Access (HSPA), and the second RAT is long term evolution (LTE) or Worldwide Interoperability for Microwave Access (WiMAX).