Control of multi-channel scan for re-establishing connections in a wirelessly networked device

• US 7,602,742 B1
• Filed: 04/25/2005
• Issued: 10/13/2009
• Est. Priority Date: 05/01/2001
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Palm, Inc. (TCL Technology Group Corp.)
• Inventors: Brown, John, Wong, William, Skinner, Craig S.
• Primary Examiner(s): RENNER, BRANDON M
• Application Number:
  US11/114,271
• Time in Patent Office: 1,632 Days
• Field of Search: 370/311, 370/312, 455/69, 455/343.2, 455/343.5, 455/515, 455/574
• US Class Current: 370/311
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0209 in terminal devices terminal devices per se H04W88/02
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 76/19 Connection re-establishment
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

To manage power in a wireless communication device, broadcast channels used by the network are scanned with a first processor in a lower power mode. The scanning is performed using a second processor that uses less power than the first processor. The scanning is performed at periodic points in time until a broadcast channel acceptable for the wireless connection is identified. The second processor is placed in the lower power mode between scans. The second processor is awakened from the lower power mode to perform the scanning.

Claims

1. A computer-implemented method for establishing a wireless connection between a computer system and a network, said method comprising:

scanning a plurality of broadcast channels used by said network with a first processor in a lower power mode, said scanning performed using a second processor that uses less power than said first processor, wherein said scanning is performed at periodic points in time until a broadcast channel acceptable for said wireless connection is identified, wherein said second processor is placed in said lower power mode between said periodic points in time and wherein said second processor is awakened from said lower power mode to perform said scanning; and

waking up said first processor provided a broadcast channel acceptable for said wireless connection is identified.

2. The method as recited in claim 1 further comprising:

comparing to a threshold a measure of signal strength of a signal received over said broadcast channel, wherein said threshold is for defining a signal strength acceptable for said wireless connection.

3. The method as recited in claim 2 further comprising:

identifying a number of broadcast channels acceptable for said wireless connection; and

sorting said number of broadcast channels according to their respective measure of signal strength.

4. The method as recited in claim 3 further comprising:

selecting from said number of broadcast channels a broadcast channel having the highest measure of signal strength; and

establishing said wireless connection using said broadcast channel having the highest measure of signal strength, wherein said establishing is performed under direction of said main processor.

5. The method as recited in claim 1 wherein said scanning further comprises:

disregarding certain broadcast channels used by said network.

6. The method as recited in claim 1 wherein said network is a Mobitex wireless communication system.

7. The method as recited in claim 1 wherein said scanning is automatically initiated when a previously established wireless connection between said computer system and said network is lost.

8. The method as recited in claim 1 wherein said scanning is automatically initiated when said computer system is powered on and an acceptable broadcast channel for said wireless connection is not acquired.

9. A computer system comprising:

a wireless transceiver;

a first processor coupled to said wireless transceiver; and

a second processor coupled to said first processor, wherein said second processor uses less power than said first processor, said second processor for executing a method for establishing a wireless connection between said computer system and a network, said method comprising;

scanning a plurality of broadcast channels used by said network with said first processor in a lower power mode, said scanning performed using said second processor, wherein said scanning is performed at periodic points in time until a broadcast channel acceptable for said wireless connection is identified, wherein said second processor is placed in said lower power mode between said periodic points in time and wherein said second processor is awakened from said lower power mode to perform said scanning; and

waking up said first processor provided a broadcast channel acceptable for said wireless connection is identified.

10. The computer system of claim 9 wherein said method further comprises:

comparing to a threshold a measure of signal strength of a signal received over said broadcast channel, wherein said threshold is for defining a signal strength acceptable for said wireless connection.

11. The computer system of claim 10 wherein said method further comprises:

identifying a number of broadcast channels acceptable for said wireless connection; and

sorting said number of broadcast channels according to their respective measure of signal strength.

12. The computer system of claim 11 wherein a broadcast channel having the highest measure of signal strength is selected from said number of broadcast channels and used for said wireless connection.

13. The computer system of claim 9 wherein said scanning of said method further comprises:

disregarding certain broadcast channels used by said network.

14. The computer system of claim 9 wherein said network is a Mobitex wireless communication system.

15. The computer system of claim 9 wherein said scanning of said method is automatically initiated when a previously established wireless connection between said computer system and said network is lost.

16. The computer system of claim 9 wherein said scanning of said method is automatically initiated when said computer system is powered on and an acceptable broadcast channel for said wireless connection is not acquired.

17. In a computer system comprising a first processor and a second processor that uses less power than said first processor, a method for establishing a wireless connection between said computer system and a network, said method comprising:

scanning a plurality of broadcast channels used by said network, wherein said scanning is performed at periodic points in time under direction of said second processor while said first processor is in a low power mode and wherein said scanning is automatically initiated in response to a triggering event;

said second processor comparing to a threshold value a measure of signal strength of each signal received over said plurality of broadcast channels, wherein said threshold is for defining a signal strength acceptable for said wireless connection; and

said second processor waking up said first processor provided a broadcast channel acceptable for said wireless connection is identified, and otherwise said second processor repeating said scanning at said periodic points in time until a broadcast channel acceptable for said wireless connection is identified, wherein said second processor is placed in said low power mode between said periodic points in time and wherein said second processor is awakened from said lower power mode to perform said scanning at said periodic points in time.

18. The method as recited in claim 17 wherein said comparing comprises:

said second processor identifying a number of broadcast channels acceptable for said wireless connection; and

said second processor ranking said number of broadcast channels according to their respective measure of signal strength.

19. The method as recited in claim 18 wherein said method further comprises:

said first processor selecting from said number of broadcast channels a broadcast channel having the highest measure of signal strength; and

said first processor establishing said wireless connection using said broadcast channel having the highest measure of signal strength.

20. The method as recited in claim 17 wherein certain broadcast channels used by said network are disregarded.

21. The method as recited in claim 17 wherein said network is a Mobitex wireless communication system.

22. The method as recited in claim 17 wherein said triggering event is loss of a previously established wireless connection between said computer system and said network.

23. The method as recited in claim 17 wherein said triggering event is lack of acquisition of a broadcast channel for said wireless connection when said computer system is powered on.