VIRTUAL GATEWAY NODE FOR DUAL-MODE WIRELESS PHONES

• US 20070268858A1
• Filed: 05/18/2007
• Published: 11/22/2007
• Est. Priority Date: 05/19/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Corporation (Broadcom, Inc.)
• Inventors: Soto, Walter G.
• Granted Patent: US 8,090,401 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 65/103 in the network
• CPC Class Codes: H04L 65/104 in the network
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1104 Session initiation protocol [SIP]
• 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 88/16 Gateway arrangements

Abstract

The invention is a virtual gateway that mediates between a dual-mode subscriber device and an IP-based PBX. In particular, the virtual gateway includes a WLAN interface for communicating with the dual-mode subscriber device and a network interface (wired or wireless) for communicating with the IP-based PBX over the Internet. As such, the virtual gateway may relay voice and call control instructions between the dual-mode subscriber device and the IP-based PBX, and may provide the same call control functions to the dual-mode subscriber device provided by the call control processor in existing dual-mode phones. The invention further provides a dual-mode subscriber device suitable for operation with the virtual gateway. Because the dual-mode subscriber device does not require a call control processor, the battery life and cost of the device are significantly improved.

Claims

1. A virtual gateway for communicating voice and call control data between an IP-based telephone switch connected via a communication link and a dual-mode subscriber device connected via a WLAN link, comprising:

a portable computing device, including

a wireless local area network interface capable of establishing a WLAN link with the dual-mode subscriber device,

a network interface capable of establishing a communication link with the IP-based telephone switch, and

a processor configured to relay voice and call control data between the dual-mode subscriber device and the IP-based telephone switch,

wherein the call control data transmitted over the communication link are in first control signaling format and the call control data transmitted over the WLAN link are in second control signaling format different than the first control signaling format.

2. The virtual gateway of claim 1, wherein the first control signaling format is one of session initiation protocol (“

SIP”

) format and H.323 format

3. The virtual gateway of claim 1, wherein the processor is further configured to translate the call control data received over the communication link to the second control signaling format for transmission over the WLAN link, and

wherein the processor is further configured to translate the call control data received over the WLAN link to the first control signaling format for transmission over the communication link.

4. The virtual gateway of claim 1, wherein the processor is further configured to create a message in the first control signaling format initiating a call from the IP-based telephone switch to the dual-mode subscriber device via the wireless communication system.

5. The method of claim 4, wherein the message initiating the call is a SIP registration message sent to the IP-based telephone switch.

6. The virtual gateway of claim 1, wherein the processor is further configured to receive from the dual-mode subscriber device a WLAN-based request to hand off the call from the wireless local area network to the wireless communication system.

7. The virtual gateway of claim 1, wherein the processor is further configured to determine whether a handoff of a call to the wireless communication system is warranted.

8. The virtual gateway of claim 7, wherein the handoff determination is made through monitoring at least one of an automatic gain control value, receive signal strength indication, packet error rate, signal to noise ratio, maximum allowable data rate, and current data transfer rate.

9. The virtual gateway of claim 1, wherein the processor is further configured to transmit a WLAN-based switchover instruction to the dual-mode subscriber device.

10. The virtual gateway of claim 1, wherein the processor is further configured to receive a call confirmation message from the IP-based telephone switch and to relay the call confirmation message to the dual-mode subscriber device.

11. The virtual gateway of claim 10, wherein the call confirmation message from the IP-base telephone switch is a SIP invite message.

12. A method for communicating voice and call control data between an IP-based telephone switch and a dual-mode subscriber device capable of operation within a wireless communication system, comprising the steps of:

establishing a WLAN link with the dual-mode subscriber device;

establishing a communication link with the IP-based telephone switch; and

relaying voice and call control data between the dual-mode subscriber device and the IP-based telephone switch,

wherein the call control data transmitted over the communication link are in a first control signaling format and the call control data transmitted over the WLAN link are in second control signaling format different than the first control signaling format.

13. The method of claim 12, wherein the first control signaling format is one of session initiation protocol (“

SIP”

) format and H.323 format.

14. The method of claim 12, further comprising the steps of:

translating the call control data received over the communication link to the second control signaling format for transmission over the WLAN link, and

translating the call control data received over the WLAN link to the first control signaling format for transmission over the communication link.

15. The method of claim 12, further comprising the step of creating a message in the first control signaling format initiating a call from the IP-based telephone switch to the dual-mode subscriber device via a wireless communication system.

16. The method of claim 15, wherein the message initiating the call is a SIP registration message sent to the IP-based telephone switch.

17. The method of claim 16, further comprising the steps of receiving a call confirmation message from the IP-based telephone switch, and relaying the call confirmation message to the dual-mode subscriber device.

18. The method of claim 17, wherein the call confirmation message from the IP-base telephone switch is a SIP invite message.

19. The method of claim 12, further comprising the step of receiving from the dual-mode subscriber device a WLAN-based request to hand off the call from the wireless local area network to a wireless communication system.

20. The method of claim 12, further comprising the step of determining whether a handoff of a call to the wireless communication system is warranted.

21. The method of claim 12, wherein the step of determining includes the step of monitoring at least one of an automatic gain control value, receive signal strength indication, packet error rate, signal to noise ratio, maximum allowable data rate, and current data transfer rate.

22. The method of claim 12, further comprising the step of transmitting a WLAN-based switchover instruction to the dual-mode subscriber device.

23. A method of handing off a call at a dual-mode subscriber device from a wireless local area network to a wireless communication system comprising:

creating, at a virtual gateway, a message in a first control signaling format initiating a call from the IP-based telephone switch to the dual-mode subscriber device via the wireless communication system;

receiving, at the dual-mode subscriber device, the call from the wireless communication system; and

switching, at the dual-mode subscriber device, the call from the wireless local area network to the connection to the wireless communication system.

24. The method of claim 23, wherein the first control signaling format is one of session initiation protocol (“

SIP”

) format and H.323 format.

25. The method of claim 23, further comprising the step of receiving, at the virtual gateway, a WLAN-based request to hand off the call from the wireless local area network to the wireless communication system.

26. The method of claim 23, further comprising the step of transmitting a WLAN-based switchover instruction from the virtual gateway to the dual-mode subscriber device.

27. The method of claim 23, wherein the message initiating the call is a SIP registration message sent to the IP-based telephone switch.

28. The method of claim 23, further comprising the step of receiving, at the virtual gateway, a SIP invite message from the IP-based telephone switch.

29. The method of claim 23 wherein the wireless communication system is a cellular system.

30. The method of claim 23, further comprising the step of determining whether a handoff to the wireless communication system is warranted.

31. The method of claim 30 wherein the handoff determination is made through monitoring at least one of an automatic gain control value, receive signal strength indication, packet error rate, signal to noise ratio, maximum allowable data rate, and current data transfer rate.

32. A dual-mode wireless communication device suitable for operation in a WLAN-based system including a wireless local area network, a virtual gateway and an IP-based telephone switch as well as in a wireless communication system, comprising:

a VoIP processing module configured to establish a WLAN-based call with the IP-based telephone switch via the virtual gateway;

a cellular processing module configured to establish a PSTN call with the wireless communication system; and

a controller module configured to switch between the WLAN-based call with the IP-based telephone switch via the virtual gateway and the PSTN call with the wireless communication system.

33. The device of claim 32, wherein the cellular processing module is configured to establish a call with the wireless communication system while a call is in progress with the IP-based telephone switch via the WLAN and the virtual gateway, and wherein the controller module is configured to switch the dual-mode wireless communication device from the call in progress over the WLAN and the virtual gateway to the call from the wireless communication system.

34. The device of claim of 33, wherein the call with the wireless communication system is established by one of (i) the cellular processing module placing a call to the wireless communication system or (ii) the cellular processing module receiving a call from the wireless communication system.

35. The device of claim 32, wherein the VoIP processing module is configured to establish a call with the IP-based telephone switch via the WLAN and the virtual gateway while a call is in progress over the wireless communication system, and wherein the controller module is configured to switch the dual-mode wireless communication device from the call in progress over the wireless communication system to the call with the IP-based telephone switch via the WLAN and the virtual gateway.

36. The device of claim of 35, wherein the call with the virtual gateway is established by one of (i) the cellular processing module placing a call to the wireless communication system or (ii) the cellular processing module receiving a call from the wireless communication system.

37. The device of claim 32, wherein the VoIP processing module is configured to receive a WLAN-based handoff instruction from the virtual gateway.

38. The device of claim 32, wherein the controller module is configured to cause the VoIP processing module to transmit a WLAN-based handoff instruction to the virtual gateway.

39. The device of claim 38, wherein the VoIP processing module is configured to transmit the handoff instruction to the virtual gateway and wherein the handoff instruction causes the virtual gateway to create and send a registration message to the IP-based telephone switch.

40. The device of claim 39, wherein the VoIP processing module is further configured to receive a call confirmation message from the virtual gateway via the wireless local area network.

41. The device of claim 40, wherein the call confirmation message originates at the IP-based telephone switch as a SIP invite message.

42. The device of claim 32, wherein the controller module is configured to determine whether a handoff of a call from the WLAN-based system to the wireless communication system is warranted.

43. The device of claim 42, wherein the controller module is configured to make the handoff determination by monitoring at least one of an automatic gain control value, receive signal strength indication, packet error rate, signal to noise ratio, maximum allowable data rate, and current data transfer rate.

44. The device of claim 32, wherein the cellular processing module is further configured to send a PSTN call initiation message to the wireless communication system specifying a surrogate called number.

45. The device of claim 32, wherein the VoIP processing module is further configured to send a WLAN call initiation message in a first control signaling format to a virtual gateway capable of converting the WLAN call initiation message to an initiation message specifying an actual called number in a second control signaling format.

46. The apparatus of claim 45 wherein the surrogate called number is assigned to an IP-based telephone switch.

47. The apparatus of claim 46 wherein the VoIP processing module is further configured to conduct a voice call to the actual called number via a call path that includes the virtual gateway and the IP-based telephone switch.

48. The device of claim 32, wherein the cellular processing module is configured to send over the wireless communication system a call initiation message in a first control signaling format specifying a telephone number associated with the IP-based telephone switch as a called party;

and

wherein the VoIP processing module is configured to send an WLAN invite message to the virtual gateway, and

wherein the virtual gateway is configured to translate the WLAN invite message into an invitation message in a second control signaling format specifying an actual called party and further configured to forward the invitation message in the second control signaling format to the IP-based telephone switch.

49. The device of claim 32, wherein the VoIP processing module is configured to receive a WLAN call invitation message from a virtual gateway, the WLAN call invitation message specifying a calling party;

and

wherein the cellular processing module is configured to send a call initiation message over the wireless communication system in response thereto.

50. The device of claim 32, wherein the VoIP processing module is configured to receive a WLAN call invitation message from a virtual gateway, the message specifying a calling party;

wherein the cellular processing module is configured to receive a call initiation message over the wireless communication system; and

wherein the controller module is configured to correlate the WLAN call invitation message with the call initiation message.

51. The device of claim 50, wherein the controller module is configured to correlate the WLAN call invitation message with the call initiation message by comparing caller ID information received over the wireless communication system with the calling party.

52. The device of claim 50, wherein the controller module is configured to correlate the WLAN call invitation message with the call initiation message by comparing caller ID information received over the wireless communication system with one or more dummy numbers.

53. A method of establishing a telephone connection at a dual-mode wireless communication device suitable for operation in a WLAN-based system including a wireless local area network, a virtual gateway and an IP-based telephone switch as well as in a wireless communication system, comprising the steps of:

establishing a WLAN-based call with the IP-based telephone switch via the virtual gateway;

establishing a cellular-based call with the wireless communication system; and

switching between the WLAN-based call established with the IP-based telephone switch via the virtual gateway and the cellular-based call with the wireless communication system.

54. The method of claim 53, further comprising the steps of:

establishing the call with the wireless communication system after the call with the IP-based telephone switch via the virtual gateway is in progress, and

switching from the call in progress via the virtual gateway to the call from the wireless communication system.

55. The method of claim of 53, wherein the step of establishing the call with the wireless communication system via the virtual gateway comprises at least one of the steps of (i) placing a PSTN call to the wireless communication system and (ii) receiving a PSTN call from the wireless communication system.

56. The method of claim 53, wherein the step of establishing a call with the IP-based telephone switch via the virtual gateway is performed after the step of establishing a call with the wireless communication system, and wherein the step of switching comprises the step of switching the dual-mode wireless communication device from the call in progress over the wireless communication system to the call with the IP-based telephone switch via the virtual gateway.

57. The method of claim of 56, wherein the step of establishing the call with the virtual gateway comprises at least one of the steps of (i) the cellular processing module placing a call to the wireless communication system or (ii) the cellular processing module receiving a call from the wireless communication system.

58. The method of claim 53, further comprising the step of receiving a WLAN-based handoff instruction via the virtual gateway.

59. The method of claim 53, further comprising the step of transmitting a WLAN-based handoff instruction to the virtual gateway.

60. The method of claim 59, further comprising the steps of translating the WLAN-based handoff instruction into registration message and sending the registration message to the IP-based telephone switch.

61. The method of claim 60, further comprising the step of receiving a call confirmation message from the virtual gateway via the wireless local area network.

62. The method of claim 61, wherein the call confirmation message originates at the IP-based telephone switch as a SIP invite message.

63. The method of claim 53, further comprising the step of determining whether a handoff of a call from the WLAN-based system to the wireless communication system is warranted.

64. The method of claim 63, wherein the step of determining includes the step of monitoring at least one of an automatic gain control value, receive signal strength indication, packet error rate, signal to noise ratio, maximum allowable data rate, and current data transfer rate.

65. The method of claim 53, further comprising the step of sending a PSTN call initiation message to the wireless communication system specifying a surrogate called number;

66. The method of claim 53, further comprising the step of sending a WLAN call initiation message specifying an actual called number in a first control signaling format from the cellular subscriber device to a virtual gateway capable of converting the WLAN call initiation message to an initiation message in a second control signaling format.

67. The apparatus of claim 66 wherein the surrogate called number is assigned to an IP-based telephone switch.

68. The apparatus of claim 67 further comprising the step of conducting a voice call to the actual called number via a call path that includes the virtual gateway and the IP-based telephone switch.

69. The method of claim 53, further comprising the steps of

sending over the wireless communication system a call initiation message specifying a telephone number associated with the IP-based telephone switch as a called party;

sending an WLAN invite message in a first control signaling format specifying an actual called party to the virtual gateway,

translating the WLAN invite message into a message in a second control signaling format; and

sending the message in the second control signaling format to the IP-based telephone switch.

70. The method of claim 53, further comprising the steps of

receiving a WLAN call invitation message from a virtual gateway, the WLAN call invitation message specifying a calling party;

and

sending a call initiation message over the wireless communication system in response thereto.

71. The method of claim 53, further comprising the steps of

receiving a WLAN call invitation message from a virtual gateway, specifying a calling party;

receiving a call initiation message over the wireless communication system ; and

correlating the WLAN call invitation message with the call initiation message.

72. The method of claim 71, wherein the step of correlating the WLAN call invitation message with the call initiation message includes the step of comparing caller ID information received over the cellular network with the calling party.

73. The method of claim 71 wherein the step of correlating the WLAN call invitation message with the call initiation message includes the step of comparing caller ID information received over the cellular network with one or more dummy numbers.