Method and system for switching a radio access technology between wireless communication systems with a multi-mode wireless transmit/receive unit

• US 7,924,785 B2
• Filed: 03/11/2005
• Issued: 04/12/2011
• Est. Priority Date: 03/12/2004
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Terry, Stephen E., Shaheen, Kamel M., Kiernan, Brian Gregory
• Primary Examiner(s): LEVITAN, DMITRY
• Application Number:
  US11/077,913
• Publication Number:
  US 20050202823A1
• Time in Patent Office: 2,223 Days
• Field of Search: 370/331, 370/335, 370/342, 455/62, 455/432.1, 455/450, 455/452.1, 455/452, 455/2, 455/436
• US Class Current: 370/331
• CPC Class Codes: H04W 36/005 involving radio access media independent information, e.g. MIH [Media independent Hand-off]
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 36/1446 wherein at least one of the networks is unlicensed
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A method and system for switching a radio access technology (RAT) between wireless communication systems connected to each other while implementing different RATs with a multi-mode WTRU are disclosed. A plurality of wireless communication systems are deployed with overlapping coverage areas wherein each system implements different RATs and are connected to each other such that a service that is provided by one system may be provided through the other system. Each wireless communication system transmits an indication of the existence of an inter-working wireless communication system in a coverage area of each system. The WTRU receives the indication and information regarding the inter-working wireless communication system. The WTRU then initiates a handoff to the inter-working wireless communication system using the received information, whereby the WTRU continues to receive the same services that the WTRU receives from the currently connected wireless communication system through the inter-working wireless communication system.

Claims

1. A method implemented in a multi-mode wireless transmit/receive unit (WTRU), the method comprising:

receiving a service from a core network via a cellular access network;

sending a first message via the cellular access network, the first message indicating that the WTRU is capable of communicating using wireless local area network (WLAN) technology;

receiving a second message via the cellular access network, wherein the second message is responsive to the first message and includes Service Set Identifiers (SSIDs) indicating WLANs available for handoff;

selecting one of the WLANs indicated by the SSIDs;

initiating a handover to the selected WLAN; and

in response to the handover, receiving the service from the core network via the selected WLAN.

2. The method of claim 1 wherein the second message includes location information for the WLANs indicated by the SSIDs.

3. The method of claim 1, further comprising:

scanning for the WLANs indicated by the SSIDs.

4. The method of claim 3 wherein the selecting one of the WLANs is based on a channel quality measurement.

5. The method of claim 1 wherein the selecting one of the WLANs is based on input from a user of the WTRU.

6. The method of claim 1 wherein the selecting one of the WLANs is based on requirements of the service.

7. The method of claim 1 wherein the receiving the service via the selected WLAN includes receiving the service via a packet data gateway (PDG).

8. The method of claim 1 wherein the cellular access network is based on Third Generation Partnership Project (3GPP) technology.

9. A wireless transmit/receive unit (WTRU) comprising:

a transmitter configured to send a first message via a cellular access network, the first message indicating that the WTRU is capable of communicating using wireless local area network (WLAN) technology;

a receiver configured;

to receive a service from a core network via the cellular access network; and

to receive a second message via the cellular access network, wherein the second message is responsive to the first message and includes Service Set Identifiers (SSIDs) of WLANs available for handoff; and

a processor configured to select one of the WLANs indicated by the SSIDs and to initiate a handover to the selected WLAN;

wherein the receiver is configured to receive the service via the selected WLAN in response to the handover.

10. The WTRU of claim 9 wherein the second message includes location information for the WLANs indicated by the SSIDs.

11. The WTRU of claim 9 wherein the receiver is further configured to scan for the WLANs indicated by the SSIDs.

12. The WTRU of claim 11 wherein the processor is configured to select one of the WLANs indicated by the SSIDs based on a channel quality measurement.

13. The WTRU of claim 9 wherein the processor is configured to select one of the WLANs based on input from a user of the WTRU.

14. The WTRU of claim 9 wherein the processor is configured to select one of the WLANs based on requirements of the service.

15. The WTRU of claim 9 wherein the receiver is configured to the receive the service via the selected WLAN via a packet data gateway (PDG).

16. The WTRU of claim 9 wherein the cellular access network is based on Third Generation Partnership Project (3GPP) technology.

17. A method for use in a wireless transmit/receive unit (WTRU), the method comprising:

receiving a service from a core network via a cellular access network;

sending a first message via the cellular access network, the first message indicating that the WTRU is capable of communicating using wireless local area network (WLAN) technology;

receiving a second message via the cellular access network that is responsive to the first message, the second message including Service Set Identifiers (SSIDs) indicating WLANs available for handoff;

selecting one of the WLANs indicated by the SSIDs;

initiating a handover to the selected WLAN; and

upon completion of the handover, receiving the service from the core network via the selected WLAN.

18. A wireless transmit/receive unit (WTRU) comprising:

a transmitter configured to send a first message via a cellular access network, the first message indicating that the WTRU is capable of communicating using wireless local area network (WLAN) technology;

a receiver configured;

to receive a service from a core network via the cellular access network; and

to receive a second message via the cellular access network, wherein the second message is responsive to the first message and includes Service Set Identifiers (SSIDs) of WLANs available for handoff; and

a processor configured to select one of the WLANs indicated by the SSIDs and to initiate a handover to the selected WLAN;

wherein the receiver is configured to receive the service via the selected WLAN upon completion of the handover.