ASSISTING RETURN TO A FIRST NETWORK FROM A SECOND NETWORK AFTER PERFORMANCE OF A CIRCUIT SWITCHED FALLBACK PROCEDURE

• US 20140247730A1
• Filed: 03/01/2013
• Published: 09/04/2014
• Est. Priority Date: 03/01/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Thota, Mohan Rao, Karri, Sai Sravan Bharadwaj
• Granted Patent: US 9,055,488 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 36/00224 between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB]
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems

Abstract

A method for assisting a wireless communication device to return to a first network from a second network is provided. The method can include the wireless communication device participating in a CSFB procedure to transition from the first network to the second network for servicing of a voice call; receiving a connection release from the second network after termination of the voice call; initiating a reselection procedure to reselect to the first network; determining presence of packet switched data ready for transmission from the wireless communication device before completion of the reselection procedure; holding the packet switched data at the wireless communication device at least until expiry of a reselection timer initiated during the reselection procedure; reselecting to the first network after expiry of the reselection timer; and initiating transmission of the packet switched data on the first network after completing reselection to the first network.

Claims

1. A method for assisting a wireless communication device to return to an LTE (Long Term Evolution) network from a legacy network, the method comprising the wireless communication device:

participating in a Circuit Switched Fallback (CSFB) procedure to transition the wireless communication device from the LTE network to a legacy network for servicing of a voice call, wherein the legacy network has a circuit switched domain and the voice call is handled by the circuit switched domain of the legacy network;

receiving a connection release from the legacy network after termination of the voice call;

initiating a reselection procedure to reselect to the LTE network;

determining presence of packet switched data ready for transmission from the wireless communication device before completion of the reselection procedure;

holding the packet switched data at the wireless communication device at least until expiry of a reselection timer initiated during the reselection procedure;

reselecting to the LTE network after expiry of the reselection timer; and

initiating transmission of the packet switched data on the LTE network after completing reselection to the LTE network.

2. The method of claim 1, further comprising:

determining whether a reselection criterion is satisfied after expiry of the reselection timer;

wherein the reselecting to the LTE network and the initiating transmission of the packet switched data on the LTE network are performed only in an instance in which it is determined that the reselection criterion is satisfied; and

wherein the method comprises remaining on the legacy network and initiating transmission of the packet switched data on the legacy network in an instance in which it is determined that the reselection criterion is not satisfied.

3. The method of claim 1, wherein the reselection timer comprises a reselection timer applied for determining whether a target LTE cell is better than a serving cell of the legacy network.

4. The method of claim 3, further comprising:

determining, after expiry of the reselection timer, whether the target LTE cell is better than the serving cell of the legacy network;

wherein the reselecting to the LTE network and the initiating transmission of the packet switched data on the LTE network are performed only in an instance in which it is determined that the target LTE cell is better than the serving cell of the legacy network; and

wherein the method comprises remaining on the legacy network and initiating transmission of the packet switched data on the legacy network in an instance in which it is determined that the target LTE cell is not better than the serving cell of the legacy network.

5. The method of claim 1, wherein the reselection timer comprises a reselection timer applied to allow the wireless communication device to measure a detected LTE cell.

6. The method of claim 5, further comprising:

determining, after expiry of the reselection timer, whether an LTE reselection criterion is satisfied based at least in part on a measurement of the detected LTE cell performed during a period of the reselection timer;

wherein the reselecting to the LTE network and the initiating transmission of the packet switched data on the LTE network are performed only in an instance in which it is determined that the LTE reselection criterion is satisfied; and

wherein the method comprises remaining on the legacy network and initiating transmission of the packet switched data on the legacy network in an instance in which it is determined that the LTE reselection criterion is not satisfied.

7. The method of claim 1, wherein determining presence of packet switched data comprises determining arrival at a cellular baseband layer of packet switched data from a layer higher than the cellular baseband layer during the reselection procedure.

8. The method of claim 1, the wireless communication device is in a radio resource control (RRC) state other than cell dedicated channel (CELL_DCH) state when the reselection procedure is initiated.

9. A method for assisting a wireless communication device to return to a first network from a second network, the method comprising the wireless communication device:

participating in a Circuit Switched Fallback (CSFB) procedure to transition the wireless communication device from the first network to the second network for servicing of a voice call;

receiving a connection release from the second network after termination of the voice call;

initiating a reselection procedure to reselect to the first network;

determining presence of packet switched data ready for transmission from the wireless communication device before completion of the reselection procedure;

holding the packet switched data at the wireless communication device at least until expiry of a reselection timer initiated during the reselection procedure;

reselecting to the first network after expiry of the reselection timer; and

initiating transmission of the packet switched data on the first network after completing reselection to the first network.

10. The method of claim 9, further comprising:

determining whether a reselection criterion is satisfied after expiry of the reselection timer;

wherein the reselecting to the first network and the initiating transmission of the packet switched data on the first network are performed only in an instance in which it is determined that the reselection criterion is satisfied; and

wherein the method comprises remaining on the second network and initiating transmission of the packet switched data on the second network in an instance in which it is determined that the reselection criterion is not satisfied.

11. The method of claim 9, wherein the first network comprises a network using a Long Term Evolution (LTE) technology, and wherein the second network comprises a legacy network having a circuit switched domain, the voice call being handled by the circuit switched domain of the legacy network.

12. A wireless communication device comprising:

at least one transceiver, the at least one transceiver configured to transmit data to and receive data from a first network and a second network; and

processing circuitry coupled to the at least one transceiver, the processing circuitry configured to control the wireless communication device to at least;

participate in a circuit switched fallback (CSFB) procedure to transition from the first network to the second network in response to initiation of a voice call;

receive a connection release from the second network after termination of the voice call;

initiate a reselection procedure to reselect to the first network;

determine presence of packet switched data ready for transmission from the wireless communication device before completion of the reselection procedure;

hold the packet switched data at the wireless communication device at least until expiry of a reselection timer initiated during the reselection procedure;

reselect to the first network after expiry of the reselection timer; and

initiate transmission of the packet switched data on the first network after completing reselection to the first network.

13. The wireless communication device of claim 12, wherein the processing circuitry is further configured to control the wireless communication device to:

determine whether a reselection criterion is satisfied after expiry of the reselection timer;

reselect to the first network and initiate transmission of the packet switched data on the first network only in an instance in which it is determined that the reselection criterion is satisfied; and

remain on the second network and initiate transmission of the packet switched data on the second network in an instance in which it is determined that the reselection criterion is not satisfied.

14. The wireless communication device of claim 12, wherein the reselection timer comprises a reselection timer applied for determining whether a target cell of the first network is better than a serving cell of the second network.

15. The wireless communication device of claim 14, wherein the processing circuitry is further configured to control the wireless communication device to:

determine, after expiry of the reselection timer, whether the target cell of the first network is better than the serving cell of the second network;

reselect to the first network and initiate transmission of the packet switched data on the first network only in an instance in which it is determined that the target cell of the first network is better than the serving cell of the second network; and

remain on the second network and initiate transmission of the packet switched data on the second network in an instance in which it is determined that the target cell of the first network is better than the serving cell of the second network.

16. The wireless communication device of claim 12, wherein the reselection timer comprises a reselection timer applied to allow the wireless communication device to measure a detected cell of the first network.

17. The wireless communication device of claim 16, wherein the processing circuitry is further configured to control the wireless communication device to:

determine, after expiry of the reselection timer, whether a reselection criterion for reselecting to the first network is satisfied based at least in part on a measurement of the detected cell of the first network performed during a period of the reselection timer;

reselect to the first network and initiate transmission of the packet switched data on the first network only in an instance in which it is determined that the reselection criterion is satisfied; and

remain on the second network and initiate transmission of the packet switched data on the second network in an instance in which it is determined that the reselection criterion is not satisfied.

18. The wireless communication device of claim 12, wherein the processing circuitry is further configured to determine presence of packet switched data in response to arrival at a cellular baseband layer of packet switched data from a layer higher than the cellular baseband layer during the reselection procedure.

19. The wireless communication device of claim 12, wherein the wireless communication device is in one of cell forward access channel (CELL_FACH) state, cell paging channel (CELL_PCH) state, Universal Terrestrial Access Network (UTRA) registration area paging channel (URA_PCH) state, or idle state when the reselection procedure is initiated.

20. The wireless communication device of claim 12, wherein the first network comprises a network using a Long Term Evolution (LTE) technology, and wherein the second network comprises a legacy network having a circuit switched domain, the voice call being handled by the circuit switched domain of the legacy network.

21. A computer program product for assisting a wireless communication device to return to a first network from a second network, the computer program product comprising at least one non-transitory computer readable storage medium having computer program code stored thereon, the computer program code comprising:

program code for participating in a Circuit Switched Fallback (CSFB) procedure to transition the wireless communication device from the first network to the second network for servicing of a voice call;

program code for receiving a connection release from the second network after termination of the voice call;

program code for initiating a reselection procedure to reselect to the first network;

program code for determining presence of packet switched data ready for transmission from the wireless communication device before completion of the reselection procedure;

program code for holding the packet switched data at the wireless communication device at least until expiry of a reselection timer initiated during the reselection procedure;

program code for reselecting to the first network after expiry of the reselection timer; and

program code for initiating transmission of the packet switched data on the first network after completing reselection to the first network.

22. The computer program product of claim 21, further comprising:

program code for determining whether a reselection criterion is satisfied after expiry of the reselection timer;

program code for reselecting to the first network and initiating transmission of the packet switched data on the first network only in an instance in which it is determined that the reselection criterion is satisfied; and

program code for remaining on the second network and initiating transmission of the packet switched data on the second network in an instance in which it is determined that the reselection criterion is not satisfied.

23. The computer program product of claim 21, wherein the reselection timer comprises a reselection timer applied for determining whether a target cell of the first network is better than a serving cell of the second network, the computer program product further comprising:

program code for determining, after expiry of the reselection timer, whether the target cell of the first network is better than the serving cell of the second network;

program code for reselecting to the first network and initiating transmission of the packet switched data on the first network only in an instance in which it is determined that the target cell of the first network is better than the serving cell of the second network; and

program code for remaining on the second network and initiating transmission of the packet switched data on the second network in an instance in which it is determined that the target cell of the first network is not better than the serving cell of the second network.

24. The computer program product of claim 21, wherein the reselection timer comprises a reselection timer applied to allow the wireless communication device to measure a detected cell of the first network, the computer program product further comprising:

program code for determining, after expiry of the reselection timer, whether a reselection criterion for reselecting to the first network is satisfied based at least in part on a measurement of the detected cell of the first network performed during a period of the reselection timer;

program code for reselecting to the first network and initiating transmission of the packet switched data on the first network only in an instance in which it is determined that the reselection criterion is satisfied; and

program code for remaining on the second network and initiating transmission of the packet switched data on the second network in an instance in which it is determined that the reselection criterion is not satisfied.

25. The computer program product of claim 21, wherein the first network comprises a network using a Long Term Evolution (LTE) technology, and wherein the second network comprises a legacy network having a circuit switched domain, the voice call being handled by the circuit switched domain of the legacy network.