METHOD AND APPARATUS FOR EFFICIENT SIGNALING AND USAGE OF RESOURCES FOR WIRELESS COMMUNICATIONS SUPPORTING CIRCUIT SWITCHED AND PACKET SWITCHED SESSIONS

• US 20110103277A1
• Filed: 10/29/2010
• Published: 05/05/2011
• Est. Priority Date: 10/30/2009
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Olvera-Hernandez, Ulises, Watfa, Mahmoud, Tamaki, Nobuyuki, Aghili, Behrouz, Tooher, John Patrick, Wang, Peter S., Adjakple, Pascal M.
• Granted Patent: US 8,705,445 B2
• Time in Patent Office: Days
• US Class Current: 370/310
• CPC Class Codes: H04B 7/2125 Synchronisation
• CPC Class Codes: H04B 7/2126 using a reference station
• CPC Class Codes: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04W 36/0022 for transferring data sessions between adjacent core network technologies
• 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 36/0033 with transfer of context information

Abstract

Method and apparatus efficiently signal and use resources for wireless communications supporting circuit switched (CS) and packet switched sessions (PS). Signaling and interaction between the wireless transmit/receive unit (WTRU), and various network entities, such as the Mobility Management Entity (MME), the Visitor Location Register (VLR), and Base Stations (BS), are used to implement circuit switched fall back (CSFB) in a PS system.

Claims

1. A method performed by a visitor location register (VLR) for avoiding an inter-system change for a wireless transmit/receive unit (WTRU) comprising:

deciding to abort a mobile terminating (MT) circuit switched fallback (CSFB) to the WTRU;

determining if a paging request to start the MT CSFB call has been sent; and

on a condition that the paging request has been sent, sending an abort message to a mobility management entity (MME) requesting the MME to cancel the MT CSFB call.

2. The method of claim 1 wherein deciding to abort the MT CSFB call is based on receiving a request to abort the MT CSFB call from the WTRU.

3. The method of claim 1 further comprising:

starting a timer when the paging request to the WTRU to establish the MT CSFB call is sent, wherein the deciding to abort the MT CSFB call is based on the timer expiring before receiving a response from the WTRU.

4. The method of claim 1 wherein the paging request is an SGsAP-Paging-Request message.

5. The method of claim 1 further comprising:

on a condition that the paging request has not been sent, aborting the MT CSFB call.

6. A visitor location register (VLR) configured to avoid an inter-system change for a wireless transmit/receive unit (WTRU) comprising:

the VLR configured to decide to abort a mobile terminating (MT) circuit switched fallback (CSFB) to the WTRU;

the VLR configured to determine if a paging request to start the MT CSFB call has been sent; and

on a condition that the paging request has been sent, the VLR configured to send an abort message to a mobility management entity (MME) requesting the MME to cancel the MT CSFB call.

7. The VLR of claim 6 wherein:

the VLR is configured to decide to abort the MT CSFB call based on receiving a request to abort the MT CSFB call from the WTRU.

8. The VLR of claim 6 wherein:

the VLR is configured to start a timer when the paging request to the WTRU to establish the MT CSFB call is sent, wherein the VLR is configured to decide to abort the MT CSFB call based on the timer expiring before receiving a response from the WTRU.

9. The VLR of claim 6 wherein the paging request is an SGsAP-Paging-Request message.

10. The VLR of claim 6 wherein:

on a condition that the paging request has not been sent, the VLR is configured to abort the MT CSFB call.

11. A method performed by a Mobility Management Entity (MME) for avoiding an inter-system change for a wireless transmit/receive unit (WTRU) comprising:

receiving an abort message from a visitor location register (VLR) indicating to the MME to cancel a mobile terminating (MT) circuit switched fallback (CSFB) call to the WTRU;

on a condition that the MME has already received an extended service request (ESR) from the WTRU, sending a service reject message to the WTRU indicating that the MT CSFB call is aborted; and

sending no further messages to the WTRU.

12. The method of claim 11 further comprising:

sending no further messages pertaining to the MT CSFB call to a mobile switching center (MSC).

13. The method of claim 11 further comprising:

sending an acknowledgment message to the VLR including a status information element (IE) indicating a result of the MT CSFB call being canceled.

14. The method of claim 11 further comprising:

sending an abort request to other network nodes.

15. The method of claim 11 further comprising:

sending a request to a Evolved Universal Terrestrial Radio Access Network (E-UTRAN) to abort a paging procedure.

16. A mobility management entity (MME) configured to avoid an inter-system change for a wireless transmit/receive unit (WTRU) comprising:

the MME configured to receive an abort message from a visitor location register (VLR) indicating to the MME to cancel a mobile terminating (MT) circuit switched fallback (CSFB) call to the WTRU;

on a condition that the MME has already received an extended service request (ESR) from the WTRU, the MME configured to send a service reject message to the WTRU indicating that the MT CSFB call is aborted; and

the MME configured to send no further messages to the WTRU.

17. The MME of claim 16 wherein:

the MME is configured to send no further messages pertaining to the MT CSFB call to a mobile switching center (MSC).

18. The MME of claim 16 wherein:

the MME is configured to send an acknowledgment message to the VLR including a status information element (IE) indicating a result of the MT CSFB call being canceled.

19. The MME of claim 16 wherein:

the MME is configured to send an abort request to other network nodes.

20. The MME of claim 16 wherein:

the MME is configured to send a request to a Evolved Universal Terrestrial Radio Access Network (E-UTRAN) to abort a paging procedure.

21. A method for synchronizing bearer contexts between a transmitter entity and a receiver entity in wireless communications comprising:

detecting an update in a status of a bearer context in a transmitter entity;

including a bearer context status information element (IE) in a next non-access stratum (NAS) message to the receiver entity, wherein the bearer context status IE is based on the update in the status of the bearer context; and

sending the next NAS message to the receiver entity.

22. The method of claim 21 wherein the bearer context is an evolved packet system (EPS) bearer context.

23. The method of claim 21 wherein the next NAS message is an extended service request (ESR) message.

24. The method of claim 21 wherein the status of the bearer context indicates if the bearer context is active or inactive.

25. The method of claim 21 wherein the transmitter entity is a wireless transmit/receive unit (WTRU) and the receiver entity is a mobility management entity (MME).

26. The method of claim 21 wherein the transmitter entity is a mobility management entity (MME) and the receiver entity is a wireless transmit/receive unit (WTRU).

27. A transmitter entity configured to synchronize bearer contexts between with a receiver entity in wireless communications comprising:

a processor configured to detect an update in a status of a bearer context in a transmitter entity;

the processor configured to include a bearer context status information element (IE) in a next non-access stratum (NAS) message to the receiver entity, wherein the bearer context status IE is based on the update in the status of the bearer context; and

a transmitter configured to send the next NAS message to the receiver entity.

28. The transmitter entity of claim 27 wherein the bearer context is an evolved packet system (EPS) bearer context.

29. The transmitter entity of claim 27 wherein the next NAS message is an extended service request (ESR) message.

30. The transmitter entity of claim 27 wherein the status of the bearer context indicates if the bearer context is active or inactive.

31. The transmitter entity of claim 27 configured as a wireless transmit/receive unit (WTRU) wherein the receiver entity is configured as a mobility management entity (MME).

32. The transmitter entity of claim 27 configured as a mobility management entity (MME) wherein the receiver entity is configured as a wireless transmit/receive unit (WTRU).