DIRECT DIGITAL SIGNAL PROCESSOR CONTROL OF MULTI-CHANNEL SCAN FOR RE-ESTABLISHING CONNECTIONS IN A WIRELESSLY NETWORKED DEVICE

• US 20100027452A1
• Filed: 10/13/2009
• Published: 02/04/2010
• Est. Priority Date: 05/01/2001
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Palm, Inc. (TCL Technology Group Corp.)
• Inventors: Wong, William, Brown, John, Skinner, Craig S.
• Granted Patent: US 8,797,931 B2
• Time in Patent Office: Days
• 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

A method and system for establishing a wireless connection between a portable computer system and a wireless network, particularly when the portable computer system goes out of coverage and a wireless connection needs to be re-established. The portable computer system has a main processor and a digital signal processor (DSP). The main processor is placed in a low power mode, conserving battery power. When the portable computer system goes out of coverage, broadcast channels used by the wireless network are scanned by the DSP instead of the main processor to identify channels that have sufficient signal strength for the wireless connection. Thus, the main processor remains in the low power mode. When the DSP identifies acceptable channels, it wakes up the main processor and identifies the channels having sufficient signal strength. The main processor then establishes a wireless connection using one of the channels identified by the DSP.

Claims

1. In a portable computer system comprising a digital signal processor (DSP) and a main processor, a method for establishing a wireless connection between said portable computer system and a wireless network, said method comprising the steps of:

a) scanning a plurality of broadcast channels used by said wireless network, wherein said step of scanning is performed under direction of said DSP while said main processor is in a low power mode;

b) determining whether a broadcast channel is acceptable for said wireless connection, wherein said step of determining is executed by said DSP while said main processor remains in said low power mode;

c) waking up said main processor provided a broadcast channel acceptable for said wireless connection is identified; and

d) identifying to said main processor said broadcast channel acceptable for said wireless connection.

2. The method as recited in claim 1 wherein step b) comprises the step of:

b1) 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 the steps of:

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 the steps of:

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

f) establishing said wireless connection using said broadcast channel selected in said step e), wherein said step of establishing is performed under direction of said main processor.

5. The method as recited in claim 1 wherein said step a) further comprises the step of:

a1) disregarding certain broadcast channels used by said wireless network.

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

7. The method as recited in claim 1 wherein said step c) further comprises the step of:

c1) repeating said steps a) and b) at periodic time intervals until said broadcast channel acceptable for said wireless connection is identified.

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

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

10. A portable computer system comprising:

a bus;

a wireless transceiver coupled to said bus;

a main processor coupled to said bus; and

a digital signal processor (DSP) coupled to said bus, said DSP for executing a method for establishing a wireless connection between said portable computer system and a wireless network, said method comprising the steps of;

a) scanning a plurality of broadcast channels used by said wireless network, wherein said step of scanning is performed while said main processor is in a low power mode;

b) determining whether a broadcast channel is acceptable for said wireless connection, wherein said step of determining is executed while said main processor remains in said low power mode;

c) waking up said main processor provided a broadcast channel acceptable for said wireless connection is identified; and

d) identifying to said main processor said broadcast channel acceptable for said wireless connection.

11. The portable computer system of claim 10 wherein said step b) of said method comprises the step of:

b1) 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.

12. The portable computer system of claim 11 wherein said method further comprises the steps of:

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.

13. The portable computer system of claim 12 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.

14. The portable computer system of claim 10 wherein said step a) of said method further comprises the step of:

a1) disregarding certain broadcast channels used by said wireless network.

15. The portable computer system of claim 10 wherein said wireless network is a Mobitex wireless communication system.

16. The portable computer system of claim 10 wherein said step c) of said method further comprises the step of:

c1) repeating said steps a) and b) at periodic time intervals until said broadcast channel acceptable for said wireless connection is identified.

17. The portable computer system of claim 10 wherein said step a) of said method is automatically initiated when a previously established wireless connection between said portable computer system and said wireless network is lost.

18. The portable computer system of claim 10 wherein said step a) of said method is automatically initiated when said portable computer system is powered on and an acceptable broadcast channel for said wireless connection is not acquired.

19. In a portable computer system comprising a digital signal processor (DSP) and a main processor, a method for establishing a wireless connection between said portable computer system and a wireless network, said method comprising the steps of:

a) scanning a plurality of broadcast channels used by said wireless network, wherein said step of scanning is performed under direction of said DSP while said main processor is in a low power mode and wherein said step of scanning is automatically initiated in response to a triggering event;

b) said DSP 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;

c) said DSP waking up said main processor provided a broadcast channel acceptable for said wireless connection is identified, and otherwise said DSP repeating said steps a) and b) until a broadcast channel acceptable for said wireless connection is identified; and

d) said DSP identifying to said main processor said broadcast channel acceptable for said wireless connection.

20. The method as recited in claim 19 wherein said step b) comprises the steps of:

b1) said DSP identifying a number of broadcast channels acceptable for said wireless connection; and

b2) said DSP ranking said number of broadcast channels according to their respective measure of signal strength.

21. The method as recited in claim 20 wherein said method further comprises the steps of:

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

f) said main processor establishing said wireless connection using said broadcast channel selected in said step e).

22. The method as recited in claim 19 wherein certain broadcast channels used by said wireless network are disregarded.

23. The method as recited in claim 19 wherein said wireless network is a Mobitex wireless communication system.

24. The method as recited in claim 19 wherein said triggering event is loss of a previously established wireless connection between said portable computer system and said wireless network.

25. The method as recited in claim 19 wherein said triggering event is lack of acquisition of a broadcast channel for said wireless connection when said portable computer system is powered on.