METHOD OF HANDLING AN INTER RAT HANDOVER IN WIRELESS COMMUNICATION SYSTEM AND RELATED COMMUNICATION DEVICE

• US 20100113024A1
• Filed: 08/05/2009
• Published: 05/06/2010
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: HTC Corporation
• Original Assignee: HTC Corporation
• Inventors: Wu, Chih-Hsiang
• Granted Patent: US 9,232,452 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00

Abstract

A method of handling an inter-RAT handover for a mobile device in a wireless communication system includes when, via a handover from a serving network using a first RAT to a target network using a second RAT, the mobile device succeeds in establishing a connection to the target network and has packet switched data for transmission, transmitting a predetermined radio resource control message, indicating existence of a packet switched signaling connection of the mobile device, to the target network.

Claims

1. A method of handling an inter-radio access technology, hereinafter called RAT, handover for a mobile device in a wireless communication system, the method comprising:

when, via a handover from a serving network using a first RAT to a target network using a second RAT, the mobile device succeeds in establishing a connection to the target network and has packet switched data for transmission, transmitting a predetermined radio resource control message, indicating existence of a packet switched signaling connection of the mobile device, to the target network.

2. The method of claim 1, wherein performing the handover from the serving network of the first RAT to the target network of the second RAT comprises receiving a HANDOVER TO UTRAN COMMAND message excluding a “

RAB info”

(“

Radio Bearer info”

) information element.

3. The method of claim 1, wherein the predetermined RRC message is a UPLINK DIRECT TRANSFER message.

4. A method of handling an inter-radio access technology, hereinafter called RAT, handover for a mobile device, the method comprising:

when the mobile device uses a first RAT and receives a message requesting device capability corresponding to a second RAT, sending a capability message comprising preparation information associated with a handover from the first RAT to the second RAT to a serving network using the first RAT.

5. The method of claim 4, further comprising forming the preparation information as a radio resource control message used in the second RAT.

6. The method of claim 5, wherein the preparation information is an INTER RAT HANDOVER INFO message.

7. The method of claim 4, wherein the capability message comprises security configuration used for packet switched domain or circuit switched domain, or the preparation information comprises the security configuration used for the packet switched domain or the circuit switched domain.

8. The method of claim 7, wherein the security configuration is a START_PS value when the security configuration is used for the packet switched domain, or the security configuration is a START_CS value when the security configuration is used for the circuit switched domain.

9. The method of claim 4, wherein the message requesting the device capability corresponding to the second RAT is a UE CAPABILITY ENQUIRY message, and the capability message is a UE CAPABILITY INFORMATION message.

10. The method of claim 4, wherein the preparation information includes capability information of the second RAT.

11. The method of claim 10, wherein the capability information of the second RAT is formed as at least one of Mobile Station Classmark 2, Mobile Station Classmark 3, MS Radio Access Capability and MS GERAN Iu mode Radio Access Capability when the second RAT is a GSM/EDEG radio access network, abbreviated to GERAN, wherein the MS GERAN Iu mode Radio Access Capability indicates that the mobile device has capability of a GERAN Iu mode.

12. A method of handling an inter-radio access technology, hereinafter called RAT, handover for a mobile device in a wireless communication system, the method comprising:

when, via a handover from a serving network using a first RAT to a target network using a second RAT, a connection to the target network is established successfully, using a START value of a packet switched domain for ciphering.

13. The method of claim 12, further comprising receiving a HANDOVER TO UTRAN COMMAND message excluding a “

RAB info”

(“

Radio Bearer info”

) information element when the handover is initiated.

14. The method of claim 12 further comprising transmitting the START value to the target network with a UE CAPABILITY INFORMATION message or a RRC CONNECTION SETUP COMPLETE message.

15. A method of handling an inter-radio access technology, hereinafter called RAT, handover for a mobile device in a wireless communication system, the method comprising:

receiving a handover initiating message comprising integrity protection information to perform a handover from a serving network using a first RAT to a target network using a second RAT; and

according to the integrity protection information, starting integrity protection from transmission of the first uplink message after the handover initiating message.

16. The method of claim 15, wherein the handover initiating message is a MobilityFromEUTRACommand message comprising a HANDOVER TO UTRAN COMMAND message, and the first uplink message after the receipt of the handover initiating message is a HANDOVER TO UTRAN COMPLETE message comprising a message authentication code.

17. The method of claim 15, wherein the integrity protection information comprises at least one of a FRESH value and information of an integrity protection algorithm.

18. A method of handling an inter-radio access technology, hereinafter called RAT, handover for a mobile device in a wireless communication system, the method comprising:

via a handover from a serving network using a first RAT to a target network using a second RAT, receiving a radio resource control message comprising location area information of the second RAT indicating a target location area; and

performing a location area update procedure when the target location area is different from a location area where the mobile device is currently situated.

19. The method of claim 18, wherein the location area update procedure is a LOCATION UPDATING procedure when the location area information of the second RAT comprises a location area code or a location area identity, or is a ROUTING AREA UPDATE procedure when the location area information of the second RAT comprises a routing area code or a routing area identity.

20. A communication device of a wireless communication system for accurately handling an inter-radio access technology, hereinafter called RAT, handover, the communication device comprising:

a computer readable recording medium for storing program code corresponding to a process; and

a processor coupled to the computer readable recording medium, for processing the program code to execute the process;

wherein the process comprises;

when the communication device receives a message requesting device capability corresponding to a second RAT, sending a capability message, comprising preparation information, associated with a handover from the first RAT to the second RAT, to a serving network using the first RAT.

21. The communication device of claim 20, wherein the process further comprises forming the preparation information as a radio resource control message used in the second RAT.

22. The communication device of claim 21, wherein the preparation information is an INTER RAT HANDOVER INFO message.

23. The communication device of claim 20, wherein the capability message further comprises security configuration used for packet switched domain or circuit switched domain, or the preparation information comprises the security configuration used for the packet switched domain or the circuit switched domain.

24. The communication device of claim 23, wherein the security configuration is a START_PS value when the security configuration is used for the packet switched domain, or the security configuration is a START_CS value when the security configuration is used for the circuit switched domain.

25. The communication device of claim 20, wherein the message requesting the device capability corresponding to the second RAT is a UE CAPABILITY ENQUIRY message, and the capability message is a UE CAPABILITY INFORMATION message.

26. The communication device of claim 20, wherein the preparation information includes capability information of the second RAT.

27. The communication device of claim 26, wherein the capability information of the second RAT is formed as at least one of Mobile Station Classmark 2, Mobile Station Classmark 3, MS Radio Access Capability and MS GERAN Iu mode Radio Access Capability when the second RAT is a GSM/EDEG radio access network, abbreviated to GERAN, wherein the MS GERAN Iu mode Radio Access Capability indicates that the mobile device has capability of a GERAN Iu mode.