WIRELESS COMMUNICATION METHOD AND SYSTEM FOR PERFORMING HANDOVER BETWEEN TWO RADIO ACCESS TECHNOLOGIES

• US 20070213059A1
• Filed: 03/07/2007
• Published: 09/13/2007
• Est. Priority Date: 03/09/2006
• Status: Abandoned Application

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Shaheen, Kamel
• Application Number:
  US11/683,037
• Publication Number:
  US 20070213059A1
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0033 with transfer of context information
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network
• CPC Class Codes: H04W 92/24 between backbone network devices

Abstract

The present invention relates to a method and apparatus for performing handover between a universal mobile telecommunication system (UMTS) terrestrial radio access network (UTRAN), and an evolved-UTRAN (E-UTRAN) based system. The wireless communication system includes a UTRAN, an E-UTRAN, a 2G/3G core network, and long term evolution (LTE) core network, and at least one wireless transmit/receive unit (WTRU) including an LTE element and ad 2G/3G element. According to the present invention the WTRU shall be able to handover a call initiated on the UTRAN to the E-UTRAN, and visa versa. The 2G/3G core network and the LTE core network are linked by a Gn interface.

Claims

1. In a wireless communication system, including a dual radio access technology (RAT) wireless transmit/receive unit (WTRU), a universal mobile telecommunication system (UMTS) terrestrial radio access network (UTRAN), an evolved-UTRAN (E-UTRAN), a 2^nd generation/3^rd generation (2G/3G) core network, and a long term evolution (LTE) network, a method of performing handover of the WTRU from E-UTRAN to UTRAN, the method comprising:

initiating a handover process, at an access gateway (AGW) based on the measurement reports sent by the WTRU;

sending a relocation request from the AGW to a target radio network controller located in the target UTRAN;

allocating resources for the WTRU in the target UTRAN;

sending a relocation response from the UTRAN to the AGW;

sending a handover command from the AGW to the WTRU;

performing an Serving Radio Network Subsystem (SRNS) relocation by sending SRNS context to the target RNC;

sending a reconfiguration complete message from the WTRU to a target serving general packet radio service (GPRS) Support Node (SGSN);

releasing the radio resources on the E-UTRAN by sending a release message to the to the E-UTRAN; and

sending an update packet data protocol (PDP) context from the target SGSN to an access server gateway (ASGW) anchor node.

2. The method of claim 1 wherein the relocation request is sent from the AGW to the target RNC via the ASGW anchor node and the SGSN.

3. The method of claim 2 wherein the ASGW acts as a source SGSN.

4. The method of claim 1 wherein allocating resources in for the WTRU in the target UTRAN includes allocating resources in the target SGSN.

5. The method of claim 1 wherein the relocation response message is sent from the UTRAN to the AGW via the ASGW anchor node.

6. The method of claim 1 wherein the handover command includes information relating to the radio access technology, channel number, routing area and location area for a new connection.

7. The method of claim 1 wherein the SRNS context message is setn tot eh target RNC via the ASGW.

8. The method of claim 1 wherein sending the update PDP context message includes updating the Qos profile.

9. The method of claim 1 wherein sending the update PDP context message includes updating the home subscriber service (HSS).

10. The method of claim 1 wherein the ASGW and the SGSN communicate over the Gn interface.

11. In a wireless communication system, including a dual radio access technology (RAT) wireless transmit/receive unit (WTRU), a universal mobile telecommunication system (UMTS) terrestrial radio access network (UTRAN), an evolved-UTRAN (E-UTRAN), a 2^nd generation/3^rd generation (2G/3G) core network, and a long term evolution (LTE) network, a method of performing handover of the WTRU from UTRAN to E-UTRAN, the method comprising:

triggering handover at an radio network controller based on measurements received from the WTRU;

determining a target evolved-node B (E-NB);

initiating a context transfer at a target access gateway (AGW);

allocating the radio resources needed for the WTRU in the E-UTRAN;

sending a handover command to the WTRU;

switching channels in the WTRU in response to the handover command;

sending a initial access message to the target AGW from the WTRU;

initiating a release operation in a serving general packet radio service (GPRS) Support Node (SGSN) to release the radio resources used by the WTRU; and

updating the a packet data protocol (PDP) context information with the target AGW.

12. The method of claim 11 wherein the determining a target E-NB includes determining a target access server gateway node ASGW anchor node.

13. The method of claim 11 wherein determining a target E-NB includes determining a target ASG.

14. The method of claim 11 wherein the handover command includes information relating to radio access technology, channel number, routing area and location area.

15. The method of claim 11 wherein the ASGW and the SGSN communicate over a Gn interface.

16. A wireless communication system for performing handover of a wireless transmit/receive unit between a universal mobile telecommunication system (UMTS) terrestrial radio access network (UTRAN), and an evolved-UTRAN (E-UTRAN), the system comprising:

a dual radio access technology (RAT) WTRU;

a 2^nd generation/3^rd generation (2G/3G) core network including an serving gateway support node (SGSN);

a UTRAN linked to the 2G/3G core network via the SGSN;

a long term evolution (LTE) network including a an access server gateway (ASGW) anchor node;

an E-UTRAN linked the to LTE core network via ASGW anchor node;

wherein the SGSN and the ASGW are communicate via an existing Gn interface.

17. The system of claim 16 wherein the UTRAN includes at least on radio network controller for communicating with a node B and the SGSN, and for triggering an handover from UTRAN to E-UTRan based on measurements received from the WTRU.

18. The system of claim 17 wherein the WTRU exchanges messages with the node B when the WTRU is operating in a 2G/3G mode.

19. The system of claim 16 wherein the LTE core network includes an access gateway (AGW) for communicating between at least one evolved—

Node B (E-NB) and the ASGW anchor node and for triggering a handover from E-UTRAN to the UTRAN based on measurements received from the WTRU.

20. The system of claim 19 wherein the WTRU exchanges messages with the E-NB when the WTRU is operating in LTE mode.

21. A dual mode wireless transmit/receive unit (WTRU) configured for performing handover between a long term evolution (LTE) network and second generation/third generation (2G/3G) network, the WTRU comprising:

an LTE element for communicating with a LTE core network; and

a 2G/3G element for communicating with a 2G/3G core network, wherein the LTE core network and the 2G/3G network communicate over a Gn interface.

22. The WTRU of claim 21 wherein the LTE element communicates with the LTE core network through and evolved node b (E-NB) located in an evolved universal mobile telecommunication system (UMTS) terrestrial radio access network (E-UTRAN).

23. The WTRU of claim 22 wherein the E-NB communicates with the LTE core network through an access gateway (AGW).

24. The WTRU of claim 23 wherein the AGW communicates is linked to the Gn interface through the access server gateway (ASGW) anchor node.

25. The WTRU of claim 21 wherein the 2G/3G element communicates with the LTE with a node B (NB) located in the universal mobile telecommunication system (UMTS) terrestrial radio access network (UTRAN).

26. The WTRU of claim 21 wherein the NB communicates with the 2G/3G core network through the serving gateway support node (SGSN) located in the 2G/3G network.

27. The WTRU of claim 21 wherein the SGSN is linked to the Gn interface.