Handover between a cellular system and a wireless local area network

• US 7,089,005 B2
• Filed: 07/25/2003
• Issued: 08/08/2006
• Est. Priority Date: 07/31/2002
• Status: Expired due to Term

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Reddy, Gautam G.
• Primary Examiner(s): Feild, Joseph
• Assistant Examiner(s): Afshar, Kamran
• Application Number:
  US10/626,940
• Publication Number:
  US 20040023669A1
• Time in Patent Office: 1,110 Days
• Field of Search: 455/422.1, 455/426.2, 455/432.1, 455/436, 455/440, 455/442, 455/444, 455/456.1, 455/456.3, 370/331, 370/436, 370/338, 709/227
• US Class Current: 455/436
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 84/04 Large scale networks; Deep hierarchical networks
• 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

Abstract

A system facilitates handover of a wireless transmit and receive unit (WTRU) between a cellular network and a wireless local area network (WLAN). The WLAN communicates with a cellular network. A location of the WTRU is determined. The coverage areas of the WLAN and cellular network are determined. The WTRU is informed of the existence of the WLAN when the WTRU approaches the coverage area of the WLAN. The WTRU is handed over from the cellular network to the WLAN when the WTRU is in the coverage area of the WLAN and vice versa.

Claims

1. System for handover of a mobile wireless transmit/receive unit (WTRU) between a cellular network and a wireless local area network (WLAN) comprising:

a network communication device in a cellular network for communicating between a WLAN and the cellular network;

a cellular network communication device in a mobile unit for communicating between the mobile unit and the cellular network;

a WLAN communication device in the mobile unit for communicating between the mobile unit and the WLAN;

a WTRU location device in the cellular network for determining the location of the mobile unit;

a WLAN location device in the cellular network for determining the coverage area of the WLAN;

a correlation device in the cellular network for correlating the location of the mobile unit with the coverage area of the WLAN;

an informing device in the cellular network for sending a message to the mobile unit informing the mobile unit of the existence of the WLAN when the mobile unit approaches the coverage area of the WLAN prior to handover;

a selection device in the mobile unit to provide user selection of the WLAN in response to the message indicating the availability of WLAN coverage, whereby the WTRU is configured to pre-select acceptance of communication through the WLAN; and

a handoff device in the mobile unit for handing over the mobile unit between the cellular network and the WLAN when the mobile unit is in the corresponding coverage area.

2. The system of claim 1 wherein the handoff device provides a handoff from the cellular network to the WLAN when the mobile unit is in the coverage area of the WLAN.

3. The system of claim 1 wherein the handoff device provides a handoff from the WLAN to the cellular network when the determined location of the mobile unit indicates the mobile unit leaving the coverage area of the WLAN.

4. The system of claim 1 further comprising WLAN information device in the cellular network to provide further information to the WTRU concerning the WLAN coverage.

5. The system of claim 4 wherein the further information concerning the WLAN coverage, comprises at least one of cost, speed of the WLAN, and user services offered by the WLAN.

6. The system of claim 5 further comprising an acceptance device to provide user acceptance of communication through the WLAN in response to the data indicating the availability of WLAN coverage and the further information.

7. The system of claim 1 further comprising:

a WLAN data device to provide data to the WTRU to indicate the availability of WLAN coverage and further information concerning the WLAN coverage, the further information comprising at least one of cost, speed of the WLAN, and user services offered by the WLAN; and

a selection device to provide user selection of the WLAN in response to the data indicating the availability of WLAN coverage and the further information, wherein the user may pre-select acceptance of communication through the WLAN according to the further information, prior to handover.

8. A wireless transmit and receive unit (WTRU) comprising:

a cellular network communication device for communicating with a cellular network and receiving a message from the cellular network prior to handover indicating the availability of a wireless local area network (WLAN) having a coverage area at a geolocation of the WTRU;

a handoff acceptance device for accepting a handing over of the WTRU from the cellular network to the WLAN after receiving the WLAN indicator information;

a WLAN communication device for communicating with the WLAN;

a selection device for providing user selection of the WLAN in response to the message indicating the availability of WLAN coverage, whereby the WTRU is configured to pre-select acceptance of handover; and

the handoff accepting device for handing over the WTRU between the cellular network and the WLAN when the WTRU is in the corresponding coverage area.

9. The WTRU of claim 8 wherein the handoff is from the cellular network to the WLAN when the WTRU has a geolocation in the coverage area of the WLAN.

10. The WTRU of claim 8 wherein the handoff is from the WLAN to the cellular network when the determined location of the WTRU indicates the WTRU leaving the coverage area of the WLAN.

11. The WTRU of claim 8 further comprising a circuit to receive data indicating the availability of WLAN coverage and further information concerning the WLAN coverage.

12. The WTRU of claim 11 wherein the further information concerning the WLAN coverage, comprises at least one of cost, speed of the WLAN, and user services offered by the WLAN.

13. The WTRU of claim 12 further comprising a circuit to provide user acceptance of communication through the WLAN in response to the data indicating the availability of WLAN coverage and the further information.

14. The WTRU of claim 8 further comprising:

a circuit to receive data indicating the availability of WLAN coverage and further information concerning the WLAN coverage, the further information comprising at least one of cost, speed of the WLAN, and user services offered by the WLAN; and

a circuit to provide user selection of the WLAN in response to the data indicating the availability of WLAN coverage and the further information, wherein the user may pre-select acceptance of communication through the WLAN according to the further information, prior to handover.

15. Method for handover of a mobile wireless transmit/receive unit (WTRU) between a cellular network and a wireless local area network (WLAN) comprising:

establishing communication between the WLAN and a cellular network;

determining in the cellular network the location of the mobile unit;

determining in the cellular network the coverage area of the WLAN;

correlating in the cellular network the location of the mobile unit with the coverage area of the WLAN;

providing user selection of the WLAN in response to a message indicating the availability of WLAN coverage, whereby the WTRU is configured to pre-select acceptance of handover;

sending the message to the mobile unit by the cellular network prior to handover informing the mobile unit of the existence of the WLAN when the location correlation indicates the mobile unit entering the coverage area of the WLAN; and

handing over the mobile unit between the cellular network and the WLAN when the mobile unit is in the corresponding coverage area.

16. The method of claim 15 wherein the handing over provides a handoff from the cellular network to the WLAN when the mobile unit is in the coverage area of the WLAN.

17. The method of claim 15 wherein the handing over the mobile unit between the cellular network and the WLAN provides a handoff from the WLAN to the cellular network when the determined location of the mobile unit indicates the mobile unit leaving the coverage area of the WLAN.

18. The method of claim 15 further comprising providing information to the WTRU to indicate the availability of WLAN coverage and further information concerning the WLAN coverage.

19. The method of claim 18 wherein the further information comprises at least one of cost, speed of the WLAN, and user services offered by the WLAN.

20. The method of claim 19 further comprising providing user acceptance of communication through the WLAN in response to the information indicating the availability of WLAN coverage and the further information.

21. The method of claim 15, further comprising the WLAN interacting with the cellular network to provide the cellular network with data concerning coverage of the WLAN and services offered by said WLAN to the mobile units.

22. The method of claim 15 further comprising:

providing data to the WTRU to indicate the availability of WLAN coverage and further information concerning the WLAN coverage, the further information comprising at least one of cost, speed of the WLAN, and user services offered by the WLAN; and

providing user selection of the WLAN in response to the data indicating the availability of WLAN coverage and the further information, wherein the user may pre-select acceptance of communication through the WLAN according to the further information, prior to handover.

23. A mobile communications system, in which a core network provides wireless service to a plurality of multi-mode mobile units, and a first local network of a first type provides communication with ones of the mobile units, wherein mobile unit communications are handed over between said first local network and a second local network of a second type with which the mobile units are configured to communicate, the system comprising:

a database, configured to be accessed by the core network, which includes information concerning the first and second local networks and geographic coverage of the first and second local networks; and

a position comparison device, configured to be accessed by the core network, to identify a position of at least one mobile unit and to correlate the geographic coverage of the first and second local networks with the position of said one mobile unit and provide information concerning the correlation to a user of said one mobile unit prior to handover;

a selection device in said one mobile unit to provide user selection of the second local network in response to receiving said information, whereby the mobile unit is configured to pre-select acceptance of communication through the second local network; and

a handover device in said one mobile unit to hand over the mobile unit between the first network and the second network when the mobile unit is in the corresponding coverage area.

24. The mobile communications system of claim 23, wherein the position identification function includes accepting signals from a GPS position locator associated with said one mobile unit.

25. The mobile communications system of claim 23, wherein the position identification function includes using network based location using signal calculations derived from communications with said one mobile unit.

26. The mobile communications system of claim 23, wherein the position identification function includes at least one of angle of arrival (AOA), time difference of arrival (TDOA) and GPS.

27. The mobile communications system of claim 23, wherein the position identification function is provided by a hybrid system using GPS position locator associated with said one mobile unit, and network based location.

28. The mobile communications system of claim 23, wherein one of the local networks is a digital cellular communications network and the other local network is a WLAN.

29. The mobile communications system of claim 23, wherein each local network interacts with the core network to provide the core network with information concerning the service area coverage of that local network and further information concerning that local network comprising at least one of cost, speed of that local network, and user services offered by that local network to the mobile units;

and

in addition to the information concerning the correlation of the geographic coverage of the first and second local networks with the position of said one mobile unit, the further information concerning at least one of the first and second local networks is provided to the user of the one mobile unit prior to handover.

30. The mobile communications system of claim 28, wherein each local network interacts with the core network to provide the position of the mobile unit when served by that local network.