Power optimized station connection manager in IEEE 802.11 type stations

• US 8,467,348 B2
• Filed: 07/09/2007
• Issued: 06/18/2013
• Est. Priority Date: 07/09/2007
• Status: Active Grant

• Current Assignee: Wipro Limited
• Original Assignee: Wipro Limited
• Inventors: Jechoux, Bruno, Fleter, Franck
• Primary Examiner(s): Eng, George
• Assistant Examiner(s): Gao, Jing
• Application Number:
  US11/774,622
• Publication Number:
  US 20090016296A1
• Time in Patent Office: 2,171 Days
• Field of Search: 370/331, 370/310, 370/328, 370/338, 455/572, 455/574
• US Class Current: 370/331
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method of managing a mobile station (e.g., IEEE 802.11 station) having a serving BSS, uses a station connection manger and initially maintains a default idle stable state with minimum power to receive incoming calls. While idle, the station periodically polls and scans a detected BSS (Access Point) to detect messages using DTIM (Delivery Traffic Indication Message). A null frame sent, triggers corresponding frame transmission at an Access Point. If the null frame is acknowledged, the station switches to the active state until end of packet exchange. With no null frame acknowledged, scanning is resumed to update a BSS list prior to joining a newly found BSS via authentication and association states. When no candidate BSS is found, a time out period is used before next polling. After the last message frame is transmitted, the station resumes the default idle state. The station manager conserves battery power in the station.

Claims

1. A method of managing a mobile station which is associated with a serving Access Point and interacting with a candidate Access Point for handoff while roaming, comprising:

initially maintaining the mobile station in a default idle stable state at a minimum level of activity and power consumption sufficient to receive an incoming call using an autonomous station connection manager, wherein the autonomous station connection manager maintains an association of the mobile station with the serving Access Point;

while in said default idle stable state, periodically polling according to a polling period and scanning calls coming into the mobile station using DTIM (Delivery Traffic Indication Message) to detect the candidate Access Point, wherein the polling period is determined by;

estimating an implementation dependent inactivity time out of each serving Access Point using a timer ramp up procedure; and

using the estimated time out to optimally set up the polling period;

sending a null frame to trigger corresponding frame transmission at the detected candidate Access Point;

verifying if the null frame is acknowledged by the detected candidate Access Point, and if the null frame is acknowledged, then configuring the autonomous station connection manager for;

checking connection status between the mobile station and the detected candidate Access Point,

initiating re-authentication and re-association of the mobile station with the detected candidate Access Point for handoff as needed using an authentication and association keep alive algorithm; and

switching the mobile station to an active state until end of packet exchange as managed internally; and

if the null frame is not acknowledged, resuming scanning to update an Access Point list prior to joining a newly found candidate Access Point via authentication and association states.

2. The method as in claim 1 further comprising continually but selectively maintaining and monitoring authentication and association, and hence receiving incoming calls including SIP (Session Initiation Protocol) proxy, and for supporting push services.

3. The method as in claim 2 wherein said push services selectively include chat session, SMS (Short Message Service) and MMS (Multimedia Messaging Service).

4. The method as in claim 1 wherein the initiating handoff and re-association is performed as needed.

5. The method as in claim 1, further comprising selectively performing by the autonomous station connection manager periodic polling of incoming calls and push messages.

6. The method as in claim 5 further comprising using a time out period when no candidate Access Point is found for hand off.

7. The method as in claim 1 further comprising controlling by the autonomous station connection manager station power modes between said default idle stable state and said active state.

8. The method as in claim 7, wherein said mobile station is battery powered, and further comprising using the association and authentication keep alive algorithm which adapts to the serving Access Points implementation dependent inactivity time out.

9. A method of managing an IEEE 802.11 type mobile station which is associated with a serving Access Point, said mobile station having a stable default idle state and a stable active state, said method comprising:

initially maintaining the mobile station in the stable default idle state at a minimum level of activity and power consumption sufficient to receive an incoming call using an autonomous station connection manager;

while in said stable default idle state, periodically polling according to a polling period and scanning calls coming into the mobile station using DTIM (Delivery Traffic Indication Message) to detect a candidate Access Point, wherein the polling period is determined by;

estimating an implementation dependent inactivity time out of each serving Access Point using a timer ramp up procedure; and

using the estimated time out to optimally set up the polling period;

sending a null frame to trigger corresponding frame transmission at the detected candidate Access Point;

verifying if the null frame is acknowledged by the detected candidate Access Point, and if the null frame is acknowledged, then configuring the autonomous station connection manager for;

checking connection status between the mobile station and the detected candidate Access Point;

initiating re-authentication and re-association of the mobile station with the detected candidate Access Point for handoff as needed using an authentication and association keep alive algorithm; and

switching the mobile station to the stable active state until end of packet exchange as managed internally; and

if the null frame is not acknowledged, resuming scanning to update an Access Point list prior to joining a newly found candidate Access Point via authentication and association states.

10. The method as in claim 9 including the step of continually but selectively maintaining and monitoring authentication and association, and hence receiving incoming calls including SIP (Session Initiation Protocol) proxy, and for supporting push services.

11. The method as in claim 10 wherein said push services selectively include chat session, SMS (Short Message Service) and MMS (Multimedia Messaging Service).

12. The method as in claim 9 wherein the initiating handoff and re-association is performed as needed.

13. The method as in claim 9, further comprising selectively performing by the autonomous station connection manager periodic polling of incoming calls and push messages.

14. The method as in claim 13 further comprising using a time out period when no candidate Access Point is found for hand off.

15. The method as in claim 9, further comprising controlling by the autonomous station connection manager station power modes between said stable default idle state and said stable active state.

16. The method as in claim 15, wherein said mobile station is battery powered, and further comprising using the association and authentication keep alive algorithm which adapts to the serving Access Points implementation dependent inactivity time out.

17. A method of managing a mobile station which is associated with a serving Access Point from a plurality of Access Points, wherein said mobile station is battery powered, comprising:

initially maintaining the mobile station in a default idle stable state at a minimum level of activity and power consumption sufficient to receive incoming calls and push messages using an autonomous station connection manager, wherein the autonomous station connection manager maintains an association of the mobile station with the serving Access Point;

while in said default idle stable state, using an autonomous station connection manager for selectively doing periodic polling according to a polling period and scanning of incoming calls and push messages using DTIM (Delivery Traffic Indication Message) to detect a candidate Access Point, wherein the polling period is determined by;

estimating an implementation dependent inactivity time out of each serving Access Point using a timer ramp up procedure; and

using the estimated time out to optimally set up the polling period;

to perform said scanning, selectively probing said serving Access Point for monitoring and maintaining connection status through null-frame transmission and trigger re-authorization, comprising the steps of;

sending a null frame to trigger corresponding frame transmission at the detected candidate Access Point;

verifying if the null frame is acknowledged by the detected candidate Access Point, and if the null frame is acknowledged then configuring the autonomous station connection manager for;

checking connection status between the mobile station and the detected candidate Access Point;

initiating re-authentication and re-association of the mobile station with the detected candidate Access Point for handoff as needed using authentication and association keep alive algorithms; and

switching the mobile station to a stable active mode until end of packet exchange as managed internally; and

,

if the null frame is not acknowledged, resuming scanning to update an Access Point list prior to joining a newly found candidate Access Point via authentication and association states.

18. A method of managing a mobile station which is associated with a serving Access Point, comprising:

using an autonomous station connection manager to maintain association of the mobile station with the serving Access Point, and initially maintaining a default idle stable state at a minimum level of activity and power consumption sufficient to receive an incoming call;

while in said default idle stable state, maintaining adaptive polling of calls coming into the mobile station using DTIM (Delivery Traffic Indication Message) according to a polling period to detect a candidate access point, wherein the polling period is determined by;

estimating an implementation dependent inactivity time out of each serving Access Point using a timer ramp up procedure; and

using the estimated time out to optimally set up the polling period;

sending a null frame to trigger corresponding frame transmission at the detected candidate Access Point;

verifying if the null frame is acknowledged by the detected candidate Access Point, and if the null frame is acknowledged, then configuring the autonomous station connection manager for;

checking connection status between the mobile station and the detected candidate Access Point;

initiating re-authentication and re-association of the mobile station with the detected candidate Access Point for handoff as needed using authentication and association keep alive algorithms; and

switching from said default idle stable state to a stable active state until end of packet exchange in the incoming call as managed internally;

if the null frame is not acknowledged, resuming scanning to update an Access Point list prior to joining a newly found candidate Access Point via authentication and association states; and

minimizing power consumption by controlling said polling, re-association and switching.

19. A non-transitory computer readable medium encoded with data/instruction which when executed by a computing platform results in execution of a method of managing a mobile station which is associated with a serving Access Point and interacting with a candidate Access Point for handoff while roaming, comprising:

initially maintaining the mobile station in a default idle stable state at a minimum level of activity and power consumption sufficient to receive an incoming call using an autonomous station connection manager, wherein the autonomous station connection manager maintains an association of the mobile station with the serving Access Point;

while in said default idle stable state, periodically polling according to a polling period and scanning calls coming into the mobile station using DTIM (Delivery Traffic Indication Message) to detect the candidate Access Point, wherein the polling period is determined by;

estimating an implementation dependent inactivity time out of each serving Access Point using, a timer ramp up procedure; and

using the estimated time out to optimally set up the polling period;

sending a null frame to trigger corresponding frame transmission at the detected candidate Access Point;

verifying if the null frame is acknowledged by the detected candidate Access Point, and if the null frame is acknowledged, then configuring the station connection manager for;

checking connection status between the mobile station and the detected candidate Access Point;

initiating re-authentication and re-association of the mobile station with the detected candidate Access Point for handoff as needed using authentication and association keep alive algorithms; and

switching the mobile station to an active state until end of packet exchange as managed internally; and

if the null frame is not acknowledged, resuming scanning to update an Access Point list prior to joining a newly found candidate Access Point via authentication and association states.

20. A non-transitory computer readable medium encoded with data/instruction which when executed by a computing platform results in execution of a method of managing an IEEE 802.11 type mobile station which is associated with a serving Access Point, said station having a stable default idle state and a stable active state, said method comprising:

initially maintaining the mobile station in the stable default idle state at a minimum level of activity and power consumption sufficient to receive an incoming call using an autonomous station connection manager, wherein the autonomous station connection manager maintains an association of the mobile station with the serving Access Point;

while in said stable default idle state, periodically polling according to a polling period and scanning calls coming into the mobile station using DTIM (Delivery Traffic Indication Message) to detect a candidate Access Point, wherein the polling period is determined by;

estimating an implementation dependent inactivity time out of each serving Access Point using a timer ramp up procedure; and

using the estimated time out to optimally set up the polling period;

sending a null frame to trigger corresponding frame transmission at the detected candidate Access Point;

verifying if the null frame is acknowledged by the detected candidate Access Point, and if the null frame is acknowledged, then configuring the autonomous station connection manager for;

checking connection status between the mobile station and the detected candidate Access Point;

initiating re-authentication and re-association of the mobile station with the detected candidate Access Point for handoff as needed using authentication and association keep alive algorithms; and

switching the mobile station to the stable active state until end of packet exchange as managed internally; and

if the null frame is not acknowledged, resuming scanning to update an Access Point list prior to joining a newly found candidate Access Point via authentication and association states.