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

• US 20050202823A1
• Filed: 03/11/2005
• Published: 09/15/2005
• Est. Priority Date: 03/12/2004
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Terry, Stephen E., Shaheen, Kamel M., Kiernan, Brian Gregory
• Granted Patent: US 7,924,785 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• 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 36/14 Reselecting a network or an air interface
• 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. In an area where a plurality of wireless communication systems are deployed with overlapping coverage areas wherein each wireless communication system implements a different radio access technology (RAT) and are configured such that a service that is provided by one wireless communication system may be provided through the other wireless communication system, a method for switching a RAT between the wireless communication systems with a multi-mode wireless transmit/receive unit (WTRU) configured to support more than one RAT, comprising:

each wireless communication system transmitting an indication of existence of an inter-working wireless communication system implementing a different RAT which is available in a coverage area of each wireless communication system;

the WTRU receiving the indication through a currently connected wireless communication system;

the WTRU receiving information regarding the inter-working wireless communication system where it is determined to handoff the WTRU to the inter-working wireless communication system; and

the WTRU initiating 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 received from the currently connected wireless communication system through the inter-working wireless communication system.

2. The method of claim 1 wherein the indication is broadcast to the WTRU.

3. The method of claim 1 wherein the indication is transmitted to the WTRU through a dedicated control channel for the WTRU.

4. The method of claim 3 wherein the indication is transmitted in response to a report specifying the capability of the WTRU to support the RAT of the inter-working wireless communication system.

5. The method of claim 4 wherein the information regarding the inter-working wireless communication system is transmitted along with the indication.

6. The method of claim 1 wherein the wireless communication systems are a wireless local area network (WLAN) and a universal mobile telecommunication system (UMTS) terrestrial radio access network (UTRAN).

7. The method of claim 6 wherein the WTRU establishes a connection with the UTRAN and receives an indication regarding availability of a WLAN within the coverage of a UTRAN cell.

8. The method of claim 7 wherein the indication includes a service set identity (SSID) of the WLAN available within the UTRAN cell.

9. The method of claim 7 wherein the information includes a location of the WLAN and public land mobile network identity.

10. The method of claim 7 wherein an association to the WLAN is based on channel quality measurement.

11. The method of claim 7 wherein connection security is enabled by wired equivalent privacy (WEP) information.

12. The method of claim 1 wherein the handoff is initiated autonomously.

13. The method of claim 1 wherein the availability of the inter-working wireless communication system is alerted to the user.

14. The method of claim 13 wherein the handoff is initiated upon request of a user.

15. The method of claim 1 wherein a new internet protocol (IP) address is provided after handoff.

16. A system for switching a radio access technology (RAT) between wireless communication systems comprising:

a plurality of wireless communication systems, each wireless communication system implementing a different RAT and having at least partially overlapping coverage areas, each wireless communication system comprising;

means for transmitting an indication of the existence of an inter-working wireless communication system which is available in an overlapping coverage area of the wireless communication systems wherein the systems are configured so that a service that is provided by one wireless communication system may be provided through the inter-working wireless communication system; and

means for transmitting an information regarding the inter-working wireless communication system; and

a wireless transmit/receive unit (WTRU) configured to support a plurality of RATs comprising;

means for receiving the indication through a currently connected wireless communication system;

means for receiving the information regarding the inter-working wireless communication system where the WTRU is to be handoff to the inter-working wireless communication system; and

means for initiating 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 received from the currently connected wireless communication system through the inter-working wireless communication system.

17. The system of claim 16 wherein the indication is broadcast to the WTRU.

18. The system of claim 16 wherein the indication is transmitted to the WTRU through a dedicated channel for the WTRU.

19. The system of claim 18 wherein the indication is transmitted in response to a report of WTRU capability supporting the RAT of the inter-working wireless communication system.

20. The system of claim 18 wherein the information regarding the inter-working wireless communication system is transmitted along with the indication.

21. The system of claim 16 wherein the wireless communication systems are a wireless local area network (WLAN) and a universal mobile telecommunication system (UMTS) terrestrial radio access network (UTRAN).

22. The system of claim 16 wherein the WTRU established a connection with the UTRAN and receives an indication regarding the availability of WLAN through the UTRAN.

23. The system of claim 22 wherein the indication includes a service set identity of the WLAN available in the UTRAN.

24. The system of claim 22 wherein the information includes a location of the WLAN and public land mobile network identity.

25. The system of claim 22 wherein an association to the WLAN is based on channel quality measurement.

26. The system of claim 22 wherein connection security is enabled by wired equivalent privacy (WEP) information.

27. The system of claim 16 wherein the handoff is initiated autonomously.

28. The system of claim 16 wherein an alert to the user is provided indicating the availability of the inter-working wireless communication system.

29. The system of claim 28 wherein the handoff is initiated upon user'"'"'s request.

30. The system of claim 16 wherein a new internet protocol (IP) address is provided after handoff.

31. In an area where a plurality of wireless communication systems are deployed with overlapping coverage areas wherein each wireless communication system implements a different radio access technology (RAT) and are configured such that a service that is provided by one wireless communication system may be provided through the other wireless communication system, a method for switching a RAT between the wireless communication systems with a multi-mode wireless transmit/receive unit (WTRU) configured to support more than one RAT, comprising:

each wireless communication system transmitting information regarding an inter-working wireless communication system implementing a different RAT which is available in a coverage area of each wireless communication system;

the WTRU receiving the information through a currently connected wireless communication system; and

the WTRU initiating a handoff to the inter-working wireless communication system using the information,

whereby the WTRU continues to receive the same services that the WTRU received from the currently connected wireless communication system through the inter-working wireless communication system.

32. The method of claim 31 wherein the transmitted information regarding an inter-working wireless communication system is a list of service set identifiers (SSIDs).

33. The method of claim 32 wherein the inter-working wireless communication system is a wireless local area network (WLAN).

34. A system for switching a radio access technology (RAT) between wireless communication systems comprising:

a plurality of wireless communication systems, each wireless communication system implementing a different RAT and having at least partially overlapping coverage areas, each wireless communication system comprising;

means for transmitting information regarding an inter-working wireless communication system which is available in an overlapping coverage area of the wireless communication systems wherein the systems are configured so that a service that is provided by one wireless communication system may be provided through the inter-working wireless communication system; and

a wireless transmit/receive unit (WTRU) configured to support a plurality of RATs comprising;

means for receiving the information through a currently connected wireless communication system; and

means for initiating 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 received from the currently connected wireless communication system through the inter-working wireless communication system.

35. The system of claim 34 wherein the information regarding an inter-working wireless communication system is a list of service set identifiers (SSIDs).

36. The system of claim 35 wherein the inter-working wireless communication system is a wireless local area network (WLAN).

37. The system of claim 34 wherein the WTRU only receives the information where it is determined that the WTRU is to be handed off to the inter-working wireless communication system.