Power management system and method for vehicle locating unit
Systems and methods for power management systems are disclosed. One embodiment of the invention includes a power management system for a vehicle locating unit, the vehicle locating unit having a receiver for receiving at an assigned message frame an intermittent transmission from a communications source, wherein each intermittent transmission includes at least one assignable message frame, the power management system including a processing device for controlling wake and sleep modes of the receiver and a memory for storing a plurality of memory bit patterns for comparison with a pattern of bits contained in some portion of an assigned message frame, wherein the processing device is configured to perform the following steps: index to the receiver's assigned message frame in the intermittent transmission, re-enter wake mode after indexing, and subject the receiver to a constant average current draw.
1. A system for power management of a vehicle locating unit, the vehicle locating unit having a receiver for receiving at an assigned message frame an intermittent transmission from a communications source, wherein each intermittent transmission includes at least one assignable message frame, the system comprising:
a processing device of the vehicle locating unit in communication with the receiver, the processing device for controlling a wake mode and a sleep mode of the receiver; and
a memory of the vehicle locating unit in communication with the processing device, the memory for storing a plurality of memory bit patterns for comparison with a pattern of bits contained in some portion of an assigned message frame that is assigned to the vehicle locating unit;
wherein the processing device is configured to perform the following:
causing the receiver to enter a wake mode to find a start of an intermittent transmission from the communications source;
in response to finding the start of the intermittent transmission, causing the receiver to enter a sleep mode;
while the receiver is in the sleep mode, indexing to the assigned message frame that is assigned to the vehicle locating unit; and
in response to indexing to the assigned message frame, causing the receiver to re-enter the wake mode and then processing the assigned message frame.
2. The system of claim 1 , wherein the processing device is further configured to perform the following:
while the receiver has re-entered the wake mode, comparing the pattern of bits contained in some portion of the assigned message frame with each of the plurality of memory bit patterns; and
in response to detecting a mismatch between the pattern of bits and each of the plurality of memory bit patterns, causing the receiver to re-enter the sleep mode.
3. The system of claim 1 , wherein the processing device is further configured to perform the following:
if an expected start of the intermittent transmission is undetected, causing the receiver to re-enter the sleep mode until an expected start of a next intermittent transmission.
4. The system of claim 1 , wherein the vehicle locating unit further comprises a transmitter for transmitting a reply code, and wherein at least one intermittent transmission includes at least one of an activate command, a de-activate command, or a speed-up command, the processing device is further configured to perform the following:
upon receipt of an activate command based on a first matching bit pattern, switching the transmitter from a deactivated state to a first slow mode state;
switching the transmitter from the first slow mode state to a second slow mode state after a first predetermined period, the second slow mode state of the transmitter to consume less power than the first slow mode state of the transmitter;
upon receipt of a speed-up command based on a second matching bit pattern, switching the transmitter from at least one of the first slow mode state or the second slow mode state to a fast mode state; and
switching the transmitter from the fast mode state to the first slow mode state after a second predetermined period.
5. The system of claim 4 , wherein the processing device is further configured to perform the following:
switching the transmitter from the second slow mode state to a third slow mode state after a third predetermined period, the third slow mode state of the transmitter to consume less power than the second slow mode state of the transmitter; and
switching the transmitter from the third slow mode state to the fast mode state upon receipt of a speed-up command based on a third matching bit pattern.
6. The system of claim 5 , wherein the processing device is further configured to de-activate the transmitter from any mode state to a deactivated state upon receipt of a de-activate command based on a fourth matching bit pattern.
7. The system of claim 2 , based on detecting the mismatch between the pattern of bits and each of the plurality of memory bit patterns, the processing device is further configured to perform the following:
causing the receiver to remain in the sleep mode until an expected start of a next intermittent transmission;
causing the receiver to enter the wake mode corresponding to the expected start of the next intermittent transmission; and
in response to detecting the expected start of the next intermittent transmission, causing the receiver to re-enter the sleep mode.
8. A method of power management for a vehicle locating unit, the vehicle locating unit having a receiver for receiving at an assigned message frame an intermittent transmission from a communications source, wherein each intermittent transmission includes at least one assignable message frame, a processing device for controlling a wake mode and a sleep mode of the receiver; and a memory for storing a plurality of memory bit patterns for comparison with a pattern of bits contained in some portion of an assigned message frame that is assigned to the vehicle locating unit, the method comprising:
causing the receiver to enter a wake mode to find a start of an intermittent transmission from the communications source;
in response to finding the start of the intermittent transmission, causing the receiver to enter a sleep mode;
while the receiver is in the sleep mode, indexing to the assigned message frame that is assigned to the vehicle locating unit; and
in response to indexing to the assigned message frame, causing the receiver to re-enter wake mode and then processing the assigned message frame.
9. The method of claim 8 , further comprising:
while the receiver has re-entered the wake mode, comparing the pattern of bits contained in some portion of the assigned message frame with each of the plurality of memory bit patterns; and
in response to detecting a mismatch between the pattern of bits and each of the plurality of memory bit patterns, causing the receiver to re-enter the sleep mode.
10. The method of claim 8 , further comprising:
if an expected start of the intermittent transmission is undetected, causing the receiver to re-enter the sleep mode until an expected start of a next intermittent transmission.
11. The method of claim 8 , further comprising assigning a message frame to the receiver.
12. The method of claim 9 , based on detecting the mismatch between the pattern of bits and each of the plurality of memory bit patterns, further comprising:
causing the receiver to remain in sleep mode until an expected start of a next intermittent transmission;
causing the receiver to enter the wake mode corresponding to the expected start of the next intermittent transmission; and
in response to detecting the expected start of the next intermittent transmission, causing the receiver to re-enter the sleep mode.
13. The method of claim 8 , wherein the vehicle locating unit further comprises a transmitter for transmitting a reply code, wherein at least one intermittent transmission includes at least one of an activate command, a de-activate command, or a speed-up command, and wherein the method further includes:
based on a first matching bit pattern indicating receipt of an activate command, switching the transmitter from a deactivated state to a first slow mode state;
switching the transmitter from the first slow mode state to a second slow mode state after a first predetermined period, wherein the second slow mode state of the transmitter consumes less power than the first slow mode state of the transmitter.
14. The method of claim 13 , further comprising:
based on a second matching bit pattern indicating receipt of a speed-up command, switching the transmitter from at least one of the first slow mode state or the second slow mode state to a fast mode state; and
switching the transmitter from the fast mode state to the first slow mode state after a second predetermined period.
15. The method of claim 14 , further comprising:
switching the transmitter from the second slow mode state to a third slow mode state after a third predetermined period, the third slow mode state of the transmitter to consume less power than the second slow mode state of the transmitter; and
based on a third matching bit pattern indicating receipt of a speed-up command, switching the transmitter from the third slow mode state to the fast mode state.
16. The system of claim 15 , further comprising:
based on a fourth matching bit pattern indicating receipt of a de-activate command, de-activating the transmitter from any mode state to a deactivated state.