Automatic and seamless vertical roaming between wireless local area network (WLAN) and wireless wide area network (WWAN) while maintaining an active voice or streaming data connection: systems, methods and program products

• US 7,561,547 B2
• Filed: 02/17/2006
• Issued: 07/14/2009
• Est. Priority Date: 12/28/2000
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Brideglall, Raj
• Primary Examiner(s): Chan; Wing F
• Assistant Examiner(s): Jones; Prenell P
• Application Number:
  US11/356,474
• Publication Number:
  US 20070091845A1
• Time in Patent Office: 1,243 Days
• Field of Search: 370/329, 370/332, 370/328, 370/331, 370/335, 370/342, 370/401, 370/349, 370/352, 370/356, 370/210, 370/341, 370/389, 370/254, 455/423, 455/424, 455/455, 455/436, 455/63, 455/452, 455/450, 455/435, 455/442, 455/465, 455/437, 709/204, 709/227, 709/232, 709/239, 709/250
• US Class Current: 370/329
• 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 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A Mobile Station (MS) is able to vertically roam in either direction between two different networks, i.e., WWAN and WLAN. The MS is equipped with a dual mode Radio for WWAN and WLAN transmissions. The WLAN Radio is linked to a WLAN Enterprise Gateway Controller (EGC) via a first air link and the WWAN Radio is linked to a WWAN Base Transceiver Station (BTS) via a second air link. An outgoing VoIP call from the WLAN Radio to a remote party on the WWAN will transition or seamlessly switch over to a WWAN connection when the MS detects packet error rates, frequent scale back or consistent signal degradation.

Claims

1. A system for automatic and seamless vertical roaming (SVR) between a wireless local area network (WLAN) and a wireless wide area network (WWAN) comprising:

a mobile station configured to communicate WWAN and WLAN transmissions to the

WWAN and the WLAN; and

command apparatus configured to initiate transfer of traffic between the mobile station and

a remote party communicated over one of the WLAN and the WWAN to the other of the WLAN and the WWAN responsive to signal degradation,

wherein the mobile station is configured to interleave WLAN data in vacant WWAN slots.

2. The system of claim 1, wherein the command apparatus is configured to initiate transfer of traffic between the mobile station and the remote party via the WWAN to the WLAN responsive to the mobile station entering an area served by the WLAN.

3. The system of claim 1, wherein the mobile station further comprises a dual mode radio configured to communicate over the WWAN and WLAN.

4. The system of claim 1, further comprising a mobile switching center configured to provide an Explicit Call Transfer (ECT) function for SVR switching between WLAN and WWAN and vice versa.

5. The system of claim 1, wherein the mobile station is configured to interleave WLAN signaling data in vacant WWAN traffic slots.

6. The system of claim 1, wherein the mobile station is configured to interleave WLAN/WWAN voice/data traffic in vacant WWAN signaling slots.

7. The system of claim 1, wherein the mobile station further comprises an SVR interface configured to link a dual mode radio API with a WWAN protocol stack and a WLAN protocol stack.

8. The system of claim 7, wherein the SVR interface further comprises a three-layer communication interface.

9. The system of claim 1, further comprising a jitter buffer in the WLAN to transform random packet arrival times into uniformly spaced streaming data.

10. The system of claim 1, further comprising circuit switching apparatus between the WWAN and the WLAN for maintaining a connection between parties on the WWAN and the WLAN when transferring from WWAN to the WLAN and vice versa.

11. A mobile device, comprising:

a dual mode radio configured to communicate over a wireless local area network (WLAN) connection and over a wireless wide area network (WWAN) connection; and

a controller configured to receive traffic over the one of the WLAN connection and the WWAN connection and transition to receive traffic over the other of the WLAN connection and the WWAN connection responsive to signal degradation;

wherein the controller is configured to interleave WLAN data in vacant WWAN slots.

12. The mobile device of claim 11, wherein the controller is configured to implement a seamless vertical roaming (SVR) interface linking a dual mode radio API with a WWAN protocol stack and a WLAN protocol stack.

13. The mobile device of claim 11, where in the controller is configured to interleave WLAN voice data in vacant WWAN signaling slots.

14. The mobile device of claim 12, wherein the controller is configured to limit a size of WLAN data packets in accordance with the available WWAN time slots.

15. The mobile device of claim 12, wherein the controller is configured to interleave WLAN signaling traffic in vacant WWAN voice/data traffic time slots.

16. The mobile device of claim 12, wherein the controller is configured to interleave WLAN voice traffic in vacant WWAN signaling traffic time slots.

17. The mobile deice of claim 11, wherein the controller is configured to interleave WWAN signaling data between WLAN packet transfers.

18. The mobile device of claim 11 further comprising a scanner coupled to the controller and configured to identify the availability of a WLAN gateway.

19. The mobile device of claim 18, where the scanner is configured to identify the availability of the WLAN gateway passively by monitoring beacon signals.

20. The mobile device of claim 18, where the scanner is configured to identify the availability of the WLAN gateway actively by sending a probe request during a first vacant WWAN time slot.

21. The mobile device of claim 19, wherein the controller is configured to direct the scanner to schedule the probe request to allow a probe response to be received by the dual mode radio over the WLAN connection during a second vacant WWAN time slot.

22. A method for automatic and seamless vertical roaming between a wireless local area network (WLAN) and a wireless wide area network (WWAN) while maintaining an active voice or data connection comprising the steps of:

issuing a command to the WWAN by a mobile station including a dual mode radio configured for WWAN and WLAN transmission, the command initiating transfer of a voice or data call on the WWAN to a remote party on the WLAN;

checking whether or not a gateway is linked to the dual mode radio for WLAN transmissions while maintaining the call between the remote party and the mobile station by interleaving WLAN signaling data in vacant WWAN slots;

verifying by the dual mode radio that a caller identification is from a WWAN transmission and signaling the WLAN gateway to accept the call by interleaving WLAN signaling data in vacant WWAN slots;

storing the packets at the mobile station while waiting for an establishment of a WLAN connection;

dropping the WWAN transmission for the call by the WWAN; and

connecting the caller via the gateway and releasing the stored packets to the dual mode radio for WLAN transmission.

24. The method of claim 22, further comprising providing an Explicit Call Transfer (ECT) function for SVR switching between WLAN/WWAN networks when a user roams in the networks.

26. The method of claim 22, further comprising:

interleaving WLAN signaling data in vacant WWAN traffic slots; and

interleaving WLAN voice/data traffic in vacant WWAN signaling slots.

28. The method of claim 22, further comprising linking a dual mode radio API with a WWAN protocol stack and a WLAN protocol stack for SVR between WWAN and WLAN and vice versa.

30. The method of claim 22, further comprising transforming random packet arrival times into uniformly spaced streaming data using a jitter buffer.

32. The method of claim 22, further comprising maintaining a connection between parties on the WWAN and the WLAN when transferring from WWAN to the WLAN and vice versa.

23. A method for automatic and seamless vertical roaming between a wireless local area network (WLAN) and a wireless wide area network (WWAN) while maintaining an active voice or data connection comprising the steps of:

issuing a command to a gateway by a mobile station including a dual mode radio configured for WWAN and WLAN transmission, the command initiating transfer of a VoIP call or data communications on the WLAN to a remote party on the WWAN;

checking by the WWAN whether or not the dual mode radio for WWAN transmissions is registered to the WWAN while maintaining the call between the remote party the and mobile station;

interleaving WLAN data in vacant WWAN slots;

verifying by the dual mode radio that a caller identification is from WLAN transmission and signaling the WWAN to accept the call;

storing the packets at the mobile station while waiting for the establishment of the WWAN connection;

dropping the WLAN transmission for the call by the WLAN; and

connecting the caller to the mobile station via the WWAN and releasing the stored packets to the dual mode Radio for WWAN transmissions.

25. The method of claim 23, further comprising providing an Explicit Call Transfer (ECT) function for SVR switching between WLAN/WWAN networks when a user roams in the networks.

27. The method of claim 23, further comprising:

interleaving WLAN signaling data in vacant WWAN traffic slots; and

interleaving WLAN voice/data traffic in vacant WWAN signaling slots.

29. The method of claim 23, further comprising linking a dual mode radio API with a WWAN protocol stack and a WLAN protocol stack for SVR between WWAN and WLAN and vice versa.

31. The method of claim 23, further comprising transforming random packet arrival times into uniformly spaced streaming data using a jitter buffer.

33. The method of claim 23, further comprising maintaining a connection between parties on the WWAN and the WLAN when transferring from WWAN to the WLAN and vice versa.