Wireless device battery conservation method and system
View Patent ↗Generally, the present invention provides a method for detecting poor RF conditions, and entering different sleep mode levels or phases in accordance with the RF conditions to save battery power. Mobile device battery life can be conserved when the mobile device detects poor RF conditions and enters a deep sleep mode of operation. In this deep sleep mode of operation the mobile device periodically samples the RF conditions and gradually increases the period between samples when the RF conditions do not improve. Because mobility can change the RF condition for wireless devices even in areas of good RF coverage, the mobile device operating in the deep sleep mode can detect this mobility and thus enhance the probability of entering an idle state, or alternatively, entering a longer power save mode. When the RF condition improves, the mobile device exits from the deep sleep mode and returns to the idle state.
1. A method of switching a mobile device having a monitored system channel to a deep sleep mode, the method comprising:
the mobile device entering the deep sleep mode when, within a timeout period, a count, performed by the mobile device, of system channel losses is a predetermined number;
incrementing a channel lost counter each time the system channel is lost; and
setting a channel lost start time value to a first current Global Positioning System time when the channel lost counter has a value of one.
2. The method of claim 1 , further comprising setting a channel lost end time value to a second current Global Positioning System time when the value of the channel lost counter reaches the predetermined number.
3. The method of claim 2 , wherein the mobile device enters the deep sleep mode when the difference between the channel lost end time value and the channel lost start time value is at least the timeout period.
4. The method of claim 1 , further comprising:
waking up from the deep sleep mode after a time interval to sample an RF condition strength of a system;
comparing the sampled RF condition strength to a predetermined level;
increasing the time interval if the sampled RF condition strength is less than the predetermined level; and,
re-entering the deep sleep mode.
5. The method of claim 4 , wherein comparing the sampled RF condition strength comprises comparing the signal to noise ratio of an RF condition to a predetermined value.
6. The method of claim 4 , wherein re-entering the deep sleep mode comprises switching the mobile device to any one of a first, second or third level deep sleep modes.
7. The method of claim 6 , wherein waking up comprises determining a system for acquisition from a list of systems associated with any one of the first, second or third level deep sleep modes.
8. The method of claim 6 , wherein comparing the sampled RF condition strength comprises setting a mobility flag to true if the mobile device is moving.
9. The method of claim 8 , wherein the mobile device returns to one of an idle state and the first level deep sleep mode when the mobility flag is true.
10. The method of claim 6 , wherein switching to any one of the first, second or third level deep sleep modes comprises setting a maximum timeout period to a predetermined timeout value associated with one of the first, second or third level deep sleep modes.
11. A mobile communications device comprising a mobile device battery power saving system for implementing the method of claim 1 .
12. A mobile device power saving system, comprising:
a channel processor to provide a flag signal indicating each loss of a system channel; and
a deep sleep controller to receive the flag signals and to count a number of times the system channel is lost within a timeout period, the deep sleep controller having a channel lost counter that is incremented each time the system channel is lost,
the deep sleep controller further setting a channel lost start time value to a first current Global Positioning System time when the channel lost counter has a value of one and providing a system lost exit flag for entering a deep sleep mode when the number of times the system channel is lost within the timeout period is a predetermined number.
13. The mobile device power saving system of claim 12 , wherein the deep sleep controller further sets a channel lost end time value to a second current Global Positioning System time when the value of the channel lost counter reaches the predetermined number.
14. The mobile device battery power saving system of claim 13 , wherein the deep sleep mode is entered when the difference between the channel lost end time value and the channel lost start time value is at least the timeout period.
15. The mobile device battery power saving system of claim 12 , wherein the deep sleep mode is one of a first, a second, or a third level deep sleep mode, each having associated therewith respective deep sleep mode level variables and a respective system acquisition list.
16. The mobile device power saving system of claim 15 , further comprising:
a variable setting controller to set the deep sleep mode level variables in response to the system lost exit flag and for adjusting the deep sleep mode level variables in response to control signals.
17. The mobile device power saving system of claim 16 , further comprising:
a low power controller to iteratively sample an RF condition parameter at a time interval defined by the deep sleep mode level variables and for providing the control signals to the variable setting controller when the RF condition fails to improve.
18. The mobile device battery power saving system of claim 17 , wherein the deep sleep mode level variables include a timer value for setting the time interval and a loop count value for setting a number of iterations.
19. The mobile device battery power saving system of claim 16 , wherein the RF condition parameter includes a signal to noise strength ratio.
20. The mobile device battery power saving system of claim 12 , wherein the system channel includes one of a pilot channel and a paging channel.