Systems and Methods for Seamlessly Roaming Between a Wireless Wide Area Network and a Wireless Local Area Network

• US 20070270145A1
• Filed: 05/06/2004
• Published: 11/22/2007
• Est. Priority Date: 05/09/2003
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Liu, Bo, Shao, Xiaoling, Feng, Lei, Du, Yonggang, Sun, Xiaolu, Tu, Jiawen, Xiaohui, Jin, Tian, Jianbo
• Granted Patent: US 8,432,868 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 72/51 based on terminal or device properties
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• 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

The present invention takes the advantage of the WLAN resources in hotspots for voice and data connections and enables seamless handover between WWAN and WLAN and vice versa. This allows two users in the hotspots to communicate with each other by making a voice over IP (VoIP) or video call, thus achieving cost savings for the end users and WWAN resources savings for the wireless operators. According to one embodiment of the invention, a mobile terminal has wireless wide area network (WWAN) and wireless local area network (WLAN) interfaces. The mobile terminal via a WWAN. If a WLAN is present, the mobile terminal sends a handover request together with its network address to the called mobile terminal, using a short message service (SMS) technique or a watermarking technique, for initiating a WLAN call with the called mobile terminal via a WLAN. After the WLAN call is established with the called mobile terminal, the mobile terminal releases the WWAN call.

Claims

1. A method performed by a mobile terminal having wireless wide area network (WWAN) and wireless local area network (WLAN) interfaces, the method comprising the steps of:

(a) detecting presence of a WWAN and a WLAN;

(b) establishing a WWAN call between the mobile terminal as a calling mobile terminal and a called mobile terminal via a WWAN;

(c) sending extra information including a handover request together with a network address of the calling mobile terminal to the called mobile terminal, for initiating a WLAN call with the called mobile terminal via a WLAN, if the WLAN is present;

(d) receiving a response from the called mobile terminal; and

(e) if the response indicates an acceptance of the handover request, establishing the WLAN call with the called mobile terminal via the WLAN.

2. The method of claim 1, further comprising the step of, after step (e), releasing the WWAN call.

3. The method of claim 1, further comprising the steps of:

during the WLAN call, detecting whether the calling mobile terminal is moving away from the WLAN; and

if the calling mobile terminal is moving away from the WLAN, establishing a new WWAN call with the called mobile terminal via the WWAN.

4. The method of claim 1, further comprising the step of:

detecting a preferred radio interface for communication based on a user profile in the calling mobile terminal;

wherein step (c) is performed if the preferred radio interface is the WLAN interface and the WLAN is present.

5. The method of claim 1, further comprising a step of:

accepting a WLAN call connection with another mobile terminal via a WLAN, as a receiving mobile terminal;

during the WLAN call, detecting whether the receiving mobile terminal is moving away from the WLAN; and

if the receiving mobile terminal is moving away from the WLAN, sending a handover request to the other mobile terminal for initiating a new WWAN call with the other mobile terminal via a WWAN.

11. The method of claim 1, wherein in step (c) the extra information is sent to the called mobile terminal using a short message service (SMS) technique.

12. The method of claim 1, wherein in step (c) the extra information is sent to the called mobile terminal using a watermarking technique.

13. The method of claim 12, wherein the extra information is sent to the called mobile terminal via a voice channel between the calling and called mobile terminals.

14. The method of claim 13, wherein the extra information is inserted in the silent durations of input voice.

15. The method of claim 11, wherein the network address is an Internet Protocol (IP) address.

6. A method performed by a calling mobile terminal having dual radio interfaces respectively for first and second wireless communication networks, the method comprising the steps of:

(a) detecting presence of the first and second wireless communication networks;

(b) establishing a first call between the mobile terminal as a calling mobile terminal and a called mobile terminal via a first wireless communication network;

(c) sending extra information including a handover request together with a network address of the calling mobile terminal in the second wireless communication network to the called mobile terminal for initiating a second call with the called mobile terminal via the second wireless communication network, if the second wireless communication network is present;

(d) receiving a response from the called mobile terminal; and

(e) if the response indicates an acceptance of the handover request, establishing the second call with the called mobile terminal via the second wireless communication network.

7. The method of claim 6, further comprising the step of, after step (e), releasing the first call.

8. The method of claim 6, further comprising the steps of:

during the second call, detecting whether the calling mobile terminal is moving away from the second wireless communication network; and

if the calling mobile terminal is moving away from the second wireless communication network, establishing a third call with the called mobile terminal via the first wireless communication network.

9. The method of claim 6, further comprising a step of:

detecting a preferred radio interface for communication based on a user profile in the calling mobile terminal;

wherein step (c) is performed if the preferred radio interface is for the second wireless communication network and the second wireless communication network is present.

10. The method of claim 6, further comprising a step of:

accepting a fourth call connection with another mobile terminal via the second wireless communication network, as a receiving mobile terminal;

during the fourth call, detecting whether the receiving mobile terminal is moving away from the second wireless communication network; and

if the receiving mobile terminal is moving away from the second wireless communication network, sending a handover request to the other mobile terminal for initiating a fifth call with the other mobile terminal via the first wireless communication network.

16. A mobile terminal having wireless wide area network (WWAN) and wireless local area network (WLAN) interfaces, comprising:

means for detecting presence of a WWAN and a WLAN;

means for establishing a WWAN call between the mobile terminal as a calling mobile terminal and a called mobile terminal via a WWAN;

means for sending extra information including a handover request together with a network address of the calling mobile terminal to the called mobile terminal, for initiating a WLAN call with the called mobile terminal via a WLAN, if the WLAN is present;

means for receiving a response from the called mobile terminal; and

means for establishing the WLAN call with the called mobile terminal via the WLAN, the WLAN call establishing means establishing the WLAN call if the response indicates an acceptance of the handover request.

17. The terminal of claim 16, further comprising

means for releasing the WWAN call, the releasing means releasing the WWAN call after the WLAN call is established.

18. The terminal of claim 16, further comprising:

means for detecting, during the WLAN call, whether the calling mobile terminal is moving away from the WLAN;

wherein the WWAN call establishing means establishes a new WWAN call with the called mobile terminal via the WWAN, if the calling mobile terminal is moving away from the WLAN.

19. The terminal of claim 16, further comprising:

means for detecting a preferred radio interface for communication based on a user profile in the calling mobile terminal;

wherein the sending means sends the extra information, if the preferred radio interface is the WLAN interface and the WLAN is present.

20. The terminal of claim 16, further comprising:

means for accepting a WLAN call connection with another mobile terminal via a WLAN, as a receiving mobile terminal;

means for detecting, during the WLAN call, whether the receiving mobile terminal is moving away from the WLAN; and

means for sending a handover request to the other mobile terminal for initiating a new WWAN call with the other mobile terminal via a WWAN, the sending means of the receiving mobile terminal sending the handover request if the receiving mobile terminal is moving away from the WLAN.

21. The terminal of claim 16, wherein the extra information is sent to the called mobile terminal using a short message service (SMS) technique.

22. The terminal of claim 16, wherein the extra information is sent to the called mobile terminal using a watermarking technique.

23. The terminal of claim 22, wherein the extra information is sent to the called mobile terminal via a voice channel between the calling and called mobile terminals.

24. The terminal of claim 22, wherein the sending means includes:

a silence control circuit that receives input voice and detects silent periods in the input voice, the control circuit outputting a control signal upon detecting a silent period;

a modulation circuit that modulates the extra information into modulated analog signals and is responsive to the control signal, the modulation circuit outputting the modulated analog signals upon receiving the control signal; and

a time division multiplexer that multiplexes the modulated analog signals into the silent periods of the input voice.

25. The terminal of claim 22, wherein the sending means includes:

a silence control circuit that receives input voice and detects silent periods in the input voice, the control circuit outputting a control signal upon detecting a silent period;

a watermarking circuit that receives the extra information and is responsive to the control signal, the watermarking circuit outputting the extra information upon receiving the control signal; and

a time division multiplexer that multiplexes the extra information into the silent periods of digitized input voice.

26. The terminal of claim 20, wherein the accepting means includes:

a frequency detection circuit that detects pre-defined frequency patterns representing digital symbols from received voice data; and

a demodulation circuit that demodulates the frequency patterns to output a corresponding digital sequence as the extra information.

27. The terminal of claim 20, wherein the accepting means includes a watermarking detection circuit that detects a pair of pre-defined digital sequences to recover a digital sequence enclosed by the pair as the extra information.

28. The terminal of claim 21, wherein the network address is an Internet Protocol (IP) address.

29. A mobile terminal having dual radio interfaces respectively for first and second wireless communication networks, comprising:

means for detecting presence of the first and second wireless communication networks;

means for establishing a first call between the mobile terminal as a calling mobile terminal and a called mobile terminal via a first wireless communication network;

means for sending extra information including a handover request together with a network address of the calling mobile terminal in the second wireless communication network to the called mobile terminal for initiating a second call with the called mobile terminal via the second wireless communication network, if the second wireless communication network is present;

means for receiving a response from the called mobile terminal; and

means for establishing the second call with the called mobile terminal via the second wireless communication network, the second call establishing means establishing the second call if the response indicates an acceptance of the handover request.

30. The terminal of claim 29, further comprising means for releasing the first call, the releasing means releasing the first call after the second call is established.

31. The terminal of claim 29, further comprising:

means for detecting, during the second call, whether the calling mobile terminal is moving away from the second wireless communication network;

wherein the first call establishing means establishes a third call with the called mobile terminal via the first wireless communication network, if the calling mobile terminal is moving away from the second wireless communication network.

32. The terminal of claim 29, further comprising:

means for detecting a preferred radio interface for communication based on a user profile in the calling mobile terminal;

wherein the sending means sends the extra information if the preferred radio interface is for the second wireless communication network and the second wireless communication network is present.

33. The terminal of claim 29, further comprising:

means for accepting a fourth call connection with another mobile terminal via the second wireless communication network, as a receiving mobile terminal; and

means for detecting, during the fourth call, whether the receiving mobile terminal is moving away from the second wireless communication network; and

means for sending a handover request to the other mobile terminal for initiating a fifth call with the other mobile terminal via the first wireless communication network, the sending means of the receiving mobile terminal sending the handover request if the receiving mobile terminal is moving away from the second wireless communication network.

34. The terminal of claim 29, wherein the extra information is sent to the called mobile terminal using a short message service (SMS) technique.

35. The terminal of claim 29, wherein the extra information is sent to the called mobile terminal using a watermarking technique.