Telephone with automatic switching between cellular and VoIP networks

• US 20050147049A1
• Filed: 01/06/2005
• Published: 07/07/2005
• Est. Priority Date: 01/06/2004
• Status: Active Grant

• Current Assignee: VASU Holdings LLC
• Original Assignee: Hava Corporation
• Inventors: Ganesan, Vasudevan
• Granted Patent: US 7,991,399 B2
• Time in Patent Office: Days
• US Class Current: 370/241
• CPC Class Codes: H04M 1/2535 adapted for voice communication over an Internet Protocol [IP] network Voice over Internet Protocol (VoIP) network equipment and services H04M7/006; implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP] H04L69/16
• CPC Class Codes: H04M 1/72403 with means for local support of applications that increase the functionality
• CPC Class Codes: H04M 1/725 Cordless telephones user interfaces specially adapted therefor H04M1/724
• CPC Class Codes: H04M 2250/06 including a wireless LAN interface
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• 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: Y02D 30/70 in wireless communication networks

Abstract

A mobile communication device includes, in part, a cellular communication module, a first antenna adapted to receive and transmit data between the mobile communication module and a cellular network, a Wireless Fidelity (Wi-Fi) communication module, a second antenna adapted to receive and transmit data between the Wi-Fi communication module and a VoIP network, a signal monitoring circuit, and a switching circuit adapted to switch an existing communication from the cellular communication module to the Wi-Fi communication module or vice versa.

Claims

1. A mobile communication device comprising:

a cellular communication module adapted to communicate with a wireless cellular network;

a Wi-Fi communication module adapted to communicate with an access point associated with a Wi-Fi network using a VoIP protocol; and

a switching circuit adapted to automatically switch operation between the cellular communication module and the Wi-Fi communication module.

2. The mobile communication device of claim 1 wherein said wireless cellular network is selected from a group consisting of GSM, CDMA, and CDMA2000 wireless cellular networks.

3. The mobile communication device of claim 2 wherein said Wi-Fi network is selected from a group consisting of an IEEE 802.11x, Wi-Fi, and WiMAX networks.

4. The mobile communication device of claim 3 further comprising:

a timer; and

a Wi-Fi signal monitor;

wherein if the Wi-Fi signal monitor detects that a first Wi-Fi signal level is greater than a first predefined threshold value V_th1, the timer is activated to establish a first time window of a first predefined size T₁, wherein if during T₁ the Wi-Fi signal monitor detects that a second Wi-Fi signal level is equal to or greater than V_th1, at the expiration of the first time window, the switching circuit sends a tear-down signal to the cellular communication module and a link-up signal to the Wi-Fi communication module, wherein said tear-down signal causes the cellular communication module to discontinue handling a previously established cellular communication and wherein said link-up signal causes the Wi-Fi communication module to handle the previously established cellular communication via a VoIP network.

5. The mobile communication device of claim 4 wherein said tear-down signal causes the cellular communication module to go into a sleep mode.

6. The mobile communication device of claim 4 wherein upon activation of the timer, the network switching circuit causes the Wi-Fi communication module to change state from a sleep mode to an active mode.

7. The mobile communication device of claim 4 wherein each of said first and second Wi-Fi signal levels is defined by a respective plurality of samples of received Wi-Fi signal.

8. The mobile communication device of claim 4 wherein if the Wi-Fi signal monitor detects that the Wi-Fi signal level is below a second predefined threshold value V_th2, the timer is activated to establish a second time window of a second predefined size T₂, wherein if during time window T₂, the Wi-Fi signal monitor detects that the Wi-Fi signal level is equal to or greater than a third predefined threshold value V_th3, a previously established VoIP communication continues without switching, wherein V_th3 is smaller than V_th2.

9. The mobile communication device of claim 8 wherein if during time window T₂, the Wi-Fi signal monitor detects that the Wi-Fi signal level is smaller than V_th3, upon expiration of time window T₂, the timer unit is activated to establish a third time window of a third predefined size T₃, where T₃ is smaller than T₂, wherein if during time window T₃ the Wi-Fi signal monitor detects that the Wi-Fi signal level is smaller than V_th3, the switching circuit sends a tear-down signal to the Wi-Fi communication module and a link-up signal to the cellular communication module, wherein said tear-down signal causes the Wi-Fi communication module to discontinue handling a previously established VoIP communication and wherein said link-up signal causes the cellular communication module to handle the previously established VoIP communication via a cellular network.

10. The mobile communication device of claim 9 wherein at the expiration of the predefine time period T₂, the network switching circuit causes the cellular communication module to change state from a sleep mode to an active mode.

11. A method comprising:

detecting a first Wi-Fi signal level;

establish a first time window of a first predefined size T₁ if the detected first Wi-Fi signal level is greater than a first predefined threshold value V_th1;

detecting a second Wi-Fi signal level during the first time window;

automatically switching a communication in progress via a cellular wireless network to a communication via a VoIP network if the second detected Wi-Fi signal level is greater than V_th1.

12. The method of claim 11 wherein said wireless cellular network is selected from a group consisting of GSM, CDMA, and CDMA2000 wireless cellular networks.

13. The method of claim 11 wherein said VoIP network is in communication with a network selected from a group consisting of an IEEE 802.11x, Wi-Fi and WiMAX networks.

14. The method of claim 11 wherein each of said first and second Wi-Fi signal levels is defined by a respective plurality of samples of received Wi-Fi signal.

15. The method of claim 11 further comprising:

detecting a third Wi-Fi signal level;

establishing a second time window of a second predefined size T₂ if the third detected Wi-Fi signal level falls below a second predefined threshold value V_th2;

detecting a fourth Wi-Fi signal level during the second time window; and

continuing a VoIP communication without change if the fourth detected Wi-Fi signal level is equal to or greater than a third predefined threshold value V_th3, wherein V_th3 is smaller than V_th2.

16. The method of claim 15 further comprising:

establishing a third time window of a third predefined size T₃ if the fourth detected Wi-Fi signal level is less than V_th3;

detecting a fifth Wi-Fi signal level during the third time window;

automatically switching a communication in progress via a VoIP wireless network to a communication via a cellular network if the fifth detected Wi-Fi signal level is less than V_th3.