Method and apparatus for low power operation of an RF wireless modem

• US 20020106997A1
• Filed: 10/11/2001
• Published: 08/08/2002
• Est. Priority Date: 10/11/2000
• Status: Active Grant

• Current Assignee: Novatel Wireless, Inc. (Inseego Corp.)
• Original Assignee: Novatel Wireless, Inc. (Inseego Corp.)
• Inventors: Meyer, Kevin, Barber, Douglas
• Granted Patent: US 6,799,030 B2
• Time in Patent Office: Days
• US Class Current: 455/343.1
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0241 where no transmission is received, e.g. out of range of the transmitter
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention provides for a method and apparatus for extending battery life in a radio frequency (“RF”) wireless modem by automatically commanding the RF modem into a low power, auto-sleep-no-coverage mode when coverage is not available. The auto-sleep-no-coverage mode timing is configurable through software parameters in the operating system of the modem. The invention conforms to the Cellular Digital Packet Data (CDPD) Specification and increases the standby time of the device outside the coverage area to that similar to the standby time when the modem is within a coverage area. One embodiment of the present invention uses two software programmable timers and a preferred embodiment of the invention uses three software programmable timers and a counter.

Claims

1. A method for causing a radio frequency (“

RF”

) modem to operate in a low power state when said modem is unable to register itself with a base station controller within said modem'"'"'s coverage area, said modem comprising a central processing unit and a first and second timer, said method comprising the steps of;

(a) setting a time duration for said first timer, wherein the time duration of said first timer is the maximum amount of time that said modem will attempt to register with a base station controller before entering into a low power state;

(b) setting a time duration for said second timer, wherein the time duration of said second timer is the amount of time that said modem will operate in said low power state;

(c) detecting that a connection to a base station controller is lost, and causing said first timer to start;

(d) attempting to register said modem with base station controller;

(e) causing said modem to operate in a normal modem active state if said modem registers with said base station controller before said first timer times out, and causing said second timer to start if said modem has failed to register with said base station controller at the point when said first timer times out;

(f) causing said modem to operate in said low power state during the duration of said second timer; and

(g) causing said modem to awaken from said low power state when said second timer times out and to return to step (c).

2. The method of claim 1, wherein said modem operates using a Cellular Digital Packet Data standard.

3. The method of claim 1, wherein said first timer is set to a time to allow said modem to scan all available channels to locate service and said second timer is set to a time that is a multiple of said first timer.

4. The method of claim 1, wherein said first timer is set for 120 seconds and said second timer is set for 1200 seconds.

5. The method of claim 1, wherein said first timer is set for 60 seconds and said second timer is set for 600 seconds.

6. The method of claim 1, further comprising notifying an attached host computing device when said modem enters into said low power state and when said modem awakens from said low power state.

7. The method of claim 1, wherein said first and second timers are software programmable timers.

8. A method for causing a radio frequency (“

RF”

) modem to operate in a low power state when said modem is unable to register itself with a base station controller within said modem'"'"'s coverage area, said modem comprising a central processing unit, a first, second and third timer and a counter, said method comprising the steps of;

(a) setting a time duration for said first timer, wherein the time duration of said first timer is the maximum amount of time that said modem will attempt to register with a base station controller before setting said counter and entering into a low power state;

(b) setting a time duration for said second timer, wherein the time duration of said second timer is the amount of time that said modem will operate in said low power state;

(c) setting a time duration for said third timer, wherein the time duration of said third timer is the maximum amount time said modem will attempt to register with a base station controller before returning to said low power state;

(d) detecting that a connection to a base station controller is lost, and causing said first timer to start;

(e) attempting to register said modem with a base station controller;

(f) causing said modem to operate in a normal modem active state if said modem registers with said base station controller before said first timer times out, and causing said counter to be set and started if said modem has failed to register with said base station controller at the point when said first timer times out, wherein said counter is the maximum number of times said modem will operate in said low power state before it returns to step (d);

(g) starting said second timer;

(h) causing said modem to operate in said low power status during the duration of said second timer;

(i) decrementing the value of said counter;

(j) detecting if the value of counter said counter is zero;

(k) causing said modem to awaken from said low power state and to return to step (d) if said counter value is zero, and causing said modem to awaken and said third timer to start if said counter value is greater than zero;

(l) attempting to register said modem with a base station controller;

(m) causing said modem to operate in a normal modem active state if said modem registers with said base station controller before said third timer times out and to return to step (f) if registration is subsequently lost, and causing said modem to return to step (g) if said modem has failed to register with said base station controller at the point when said third timer times out.

9. The method of claim 8, wherein said modem operates using a Cellular Digital Packet Data standard.

10. The method of claim 8, wherein said first timer is set to a time to allow said modem to scan all available channels to locate service, said third timer is set to allow said modem to scan a subset of said available channels, and said second timer is set to a time that is a multiple of said third timer.

11. The method of claim 10, wherein said subset of available channels is a list of preferred channels.

12. The method of claim 8, wherein said first timer is set for 120 seconds, said second timer is set for 600 seconds, said third timer is set for 60 seconds and said counter is set to a value of three.

13. The method of claim 8, wherein said first timer is set for 60 seconds, said second timer is set for 600 seconds, said third timer is set for 60 seconds and said counter is set to a value of three.

14. The method of claim 8, wherein said first timer is set for 120 seconds, said second timer is set for 150 seconds, said third timer is set for 15 seconds and said counter is set to a value of three.

15. The method of claim 8, wherein said first timer is set for 60 seconds, said second timer is set for 150 seconds, said third timer is set for 15 seconds and said counter is set to a value of three.

16. The method of claim 8, further comprising notifying an attached host computing device when said modem enters into said low power state and when said modem awakens from said low power state.

17. The method of claim 8, wherein said counter and said first, second and third timers are software programmable.

18. A wireless radio frequency (“

RF”

) modem, said modem having an antenna, an RF head, a baseband processing unit, a memory for storing modem operating system instructions, and a central processing unit (“

CPU”

) for attempting to register said modem with a base station controller within said modem'"'"'s coverage area and for detecting that a connection to a base station controller has been lost, the improvement comprising;

a first timer coupled to said CPU that is set to a time duration that is the maximum amount of time that said modem will attempt to register with a base station controller before operating in a low power state;

means coupled to said first timer for starting said first timer, said means responsive to a detection that a connection to a base station controller has been lost;

a second timer coupled to said CPU that is set to a duration that is the amount of time that said modem will operate in said low power state; and

means coupled to said second timer for starting said second timer, said means responsive to said first timer timing out;

wherein said CPU is operative under the control of said operating system instructions to cause said modem to operate in a normal modem active state when said modem registers with a base station controller before said first timer times out, said CPU is further operative to cause said modem to operate in said low power state for the time duration of said second timer when said modem is unable to register itself with a base station controller before said first timer times out, and said CPU is further operative to cause said modem to awaken from said low power state and attempt to register with a base station controller at the point when said second timer timers out.

19. A wireless radio frequency (“

RF”

) modem, said modem having an antenna, an RF head, a baseband processing unit, a memory for storing modem operating system instructions, and a central processing unit (“

CPU”

) for attempting to register said modem with a base station controller within said modem'"'"'s coverage area and for detecting that a connection to a base station controller has been lost, the improvement comprising;

a first timer coupled to said CPU that is set to a time duration that is the maximum amount of time that said modem will attempt to register with a base station controller before operating in a low power state;

means coupled to said first timer for starting said first timer, said means responsive to a detection that a connection to a base station controller has been lost;

a second timer coupled to said CPU that is set to a duration that is the amount of time that said modem will operate in said low power state;

means coupled to said second timer for starting said second timer, said means responsive to said first timer timing out;

a counter coupled to said CPU that is set to a value that is the maximum number of times said modem will operate in said low power state before restarting said first timer and attempting to register said modem with a base station controller;

means coupled to said counter for setting and starting said counter, said means responsive to said first timer timing out;

means coupled to said counter for detecting the value of said counter;

a third timer coupled to said CPU that is set to a time duration that is the maximum amount of time that said modem will attempt to register with a base station controller before re-entering said low power state after sleeping for a time determined by said second timer; and

means coupled to said third timer for starting said second timer, said means responsive to a detection that said counter is greater than zero;

wherein said CPU is operative under the control of said operating system instructions to cause said modem to operate in a normal modem active state when said modem registers with a base station controller before said first timer times out, said CPU is further operative to cause said modem to operate in said low power state for the time duration of said second timer when said modem is unable to register itself with a base station controller before said first timer times out, said CPU is further operative when said counter value is zero to cause said modem to awaken from said low power state and to attempt to register with a base station controller at the point when said second timer timers out, said CPU is further operative to cause said modem to operate in a normal modem active state when said modem registers with a base station controller before said third timer times out, and said CPU is further operative to cause said modem to operate in said low power state for the time duration of said second timer when said modem is unable to register itself with a base station controller before said third timer times out.