System, method and device for handling voice calls on a dual-mode wireless mobile communication device

• US 8,532,059 B2
• Filed: 09/14/2012
• Issued: 09/10/2013
• Est. Priority Date: 01/25/2010
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: George, Richard John, Lim, Miranda Bing Ying, Buzdugan, Marian Constantin
• Primary Examiner(s): Yao, Kwang B
• Assistant Examiner(s): NGO, NGUYEN HOANG
• Application Number:
  US13/616,729
• Publication Number:
  US 20130040638A1
• Time in Patent Office: 361 Days
• Field of Search: 370/229, 370/230, 370/310, 370/328, 370/331, 370/332
• US Class Current: 370/331
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 36/008375 based on historical data
• CPC Class Codes: H04W 36/1446 wherein at least one of the networks is unlicensed
• CPC Class Codes: H04W 36/302 due to low signal strength
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• 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

To handle a communication session at a wireless mobile communications device, after receiving an indication of current signal strength of an access point for a wireless local area network (“WLAN”) a signal strength threshold associated with the access point is retrieved. If the communication session is currently carried by a cellular network and the current signal strength exceeds the signal strength threshold, the communication session is switched from the cellular network to the WLAN. A metric is then adjusted based on timing of the switch relative to any switch of the communication session from the WLAN to the cellular network over a preceding time window associated with the access point. Based on the metric, the signal strength threshold associated with the access point is selectively adjusted.

Claims

1. A method of handling a communication session, comprising:

at a wireless mobile communications device;

receiving an indication of current signal strength of an access point for a wireless local area network (“

WLAN”

);

retrieving a signal strength threshold associated with said access point;

if said communication session is currently carried by a cellular network and said current signal strength exceeds said signal strength threshold, attempting to switch said communication session from said cellular network to said WLAN;

if said attempting to switch fails, adjusting a failure rate associated with said access point and selectively decreasing said signal strength threshold if said failure rate is below a minimum threshold for said failure rate;

wherein said failure rate is based on an average switch failure rate, at said wireless mobile communications device, from said cellular network to said access point of said WLAN within a predefined time window.

2. The method of claim 1, wherein if said attempting to switch succeeds, adjusting a success rate of switches from said cellular network to said WLAN and if said success rate exceeds a maximum threshold, adjusting said signal strength threshold associated with said access point to increase said signal strength threshold.

3. The method of claim 2 wherein said success rate associated with said access point is based on a number of switches of said communication session from cellular network to said WLAN over a preceding time window.

4. The method of claim 2 wherein said adjusting comprises adjusting said signal strength threshold by a pre-defined increment.

5. The method of claim 1, wherein said preceding time window is one week.

6. The method of claim 1, wherein said communication session is a voice call.

7. A method of handling a communication session, comprising:

at a wireless mobile communications device;

receiving an indication of current signal strength of an access point for a wireless local area network (“

WLAN”

);

retrieving a signal strength threshold associated with said access point;

if said communication session is currently carried by said WLAN and said current signal strength is below said signal strength threshold, attempting to switch said communication session from said WLAN to a cellular network;

adjusting a metric associated with said access point based on whether said attempting to switch said communication session from said WLAN to said cellular network succeeded; and

based on said metric, adjusting said signal strength threshold associated with said access point if said metric exceeds a maximum threshold;

wherein said metric is a failure rate based on an average rate of failed switches, at said wireless mobile communications device, from said access point of said WLAN to said cellular network, within a preceding time window.

8. The method of claim 7 wherein said metric is a first metric and further comprising adjusting a second metric associated with said access point based on whether said attempting to switch said communication session from said WLAN to said cellular network succeeded wherein said second metric is a success rate of switches from said WLAN to said cellular network and further comprising decreasing said signal strength threshold if said success rate exceeds a maximum threshold for said success rate.

9. The method of claim 7, wherein said preceding time window is one week.

10. The method of claim 7, wherein said communication session is a voice call.

11. A non-transitory computer readable medium embedded with a computer executable program which when executed by a processor of a dual mode mobile communication device, cause said processor to:

during a communication session;

receive an indication of current signal strength of an access point for a wireless local area network (“

WLAN”

);

retrieve a signal strength threshold associated with said access point;

if said communication session is currently carried by a cellular network and said current signal strength exceeds said signal strength threshold, attempting to switch said communication session from said cellular network to said WLAN;

adjust a metric associated with said access point based on whether said attempting to switch said communication session from cellular network to said WLAN succeeded; and

if said metric exceeds a maximum threshold, adjust said signal strength threshold associated with said access point

wherein said adjusting is selectively adjusting and said metric is a failure rate and wherein if an average of a signal strength of said access point upon each failure used in determining said failure rate is below said signal strength threshold, adjusting said signal strength threshold associated with said access point upwardly.

12. A method of handling a communication session, comprising:

at a wireless mobile communications device;

receiving an indication of current signal strength of an access point for a wireless local area network (“

WLAN”

);

retrieving a signal strength threshold associated with said access point;

if said communication session is currently carried by a cellular network and said current signal strength exceeds said signal strength threshold, attempting to switch said communication session from said cellular network to said WLAN;

adjusting a failure rate associated with said access point based on whether said attempting to switch said communication session from cellular network to said WLAN succeeded;

selectively changing said signal strength threshold if said failure rate is below a minimum threshold for said failure rate; and

selectively changing a load level threshold associated with said access point if said failure rate is below said minimum threshold for said failure rate.

13. The method of claim 12 wherein said attempting to switch is dependent upon a current load level associated with said access point being less than said load level threshold.

14. A method of handling a communication session, comprising:

at a wireless mobile communications device;

receiving an indication of current signal strength of an access point for a wireless local area network (“

WLAN”

);

retrieving a signal strength threshold associated with said access point;

if said communication session is currently carried by said WLAN and said current signal strength is below said signal strength threshold, attempting to switch said communication session from said WLAN to a cellular network;

adjusting a metric associated with said access point based on whether said attempting to switch said communication session from said WLAN to said cellular network succeeded; and

based on said metric, adjusting said signal strength threshold associated with said access point if said metric exceeds a maximum threshold;

wherein said adjusting is selectively adjusting and said metric is a failure rate and wherein if an average of a signal strength of said access point upon each failure used in determining said failure rate is below said signal strength threshold, adjusting said signal strength threshold associated with said access point upwardly.

15. The method of claim 14, wherein if an average of a load level of said access point upon each failure used in determining said failure rate is below a load level threshold, adjusting said load level threshold associated with said access point downwardly.

16. The method of claim 15 wherein said attempting to switch is dependent upon a current load level associated with said access point being less than said load level threshold.

17. The method of claim 14 wherein said adjusting comprises adjusting said signal strength threshold by a pre-defined increment.