REDUCED TERMINAL POWER CONSUMPTION VIA USE OF ACTIVE HOLD STATE

• US 20070195723A1
• Filed: 02/20/2007
• Published: 08/23/2007
• Est. Priority Date: 02/21/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Bhushan, Naga, Attar, Rashid Ahmed Akbar, Au, Jean Put Ling
• Granted Patent: US 8,689,025 B2
• Time in Patent Office: Days
• US Class Current: 370/318
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An access terminal (AT) in a cellular communication system is configured to operate in an active hold (AH) state, a transitional state between traffic and dormant states. The AT applies power to its transmit chain with a low duty cycle while in the AH state, conserving battery power. To improve robustness of the communications, the radio network may power control the AT to a higher level relative to the power control level of the AT in the traffic state. Transition from the traffic state to the AH state may be initiated after a brief period of inactivity on the reverse link. The AT may remain in the AH state while receiving forward link payload data. Transmission of a reverse link payload packet in the AH state may initiate transition to the traffic state. A prolonged period of inactivity may initiate a transition from the AH state to the dormant state.

Claims

1. A wireless access terminal for communicating with a base transceiver station of a radio network, the wireless access terminal comprising:

a receiver configured to receive forward link transmissions from the base transceiver station;

a transmitter configured to send reverse link transmissions to the base transceiver station;

a memory storing program code; and

a controller coupled to the receiver, transmitter, and the memory, wherein the controller is configured to execute the program code to cause the wireless access terminal to;

initiate a transition from a traffic state to an active hold state in response to absence of reverse link traffic during a first predetermined time period,

initiate a transition from the active hold state to the traffic state in response to presence of reverse link traffic,

initiate a transition from the active hold state to a dormant state in response to absence of forward link traffic and reverse link traffic during a second predetermined period,

initiate a transition from the dormant state to the traffic state in response to presence of reverse link traffic,

remain in the active hold state after transitioning into the active hold state during simultaneous presence of forward link traffic and absence of reverse link traffic, and

power off at least one component of the transmitter in the active hold state so that duty cycle of said at least one component is less than twenty-five percent in the active hold state.

2. The wireless access terminal of claim 1, wherein the controller is further configured to execute the program code to cause the wireless access terminal to power on said at least one component of the transmitter for at least a majority of time in the traffic state.

3. The wireless access terminal of claim 2, wherein the controller is further configured to execute the program code to cause the wireless access terminal to provide feedback to the base transceiver station with a first frequency in the active hold state, and to provide feedback to the base transceiver station with a second frequency in the traffic state, the second frequency being greater than the first frequency.

4. The wireless access terminal of claim 3, wherein the second frequency is twice the first frequency.

5. The wireless access terminal of claim 3, wherein the second frequency is four time the first frequency.

6. The wireless access terminal of claim 3, wherein the feedback comprises reverse link pilot and forward link rate control.

7. The wireless access terminal of claim 2, wherein the controller is further configured to execute the program code to cause the wireless access terminal to provide feedback to the base transceiver station once in eight slots in the active hold state, and to provide feedback to the base transceiver station once in four slots in the traffic state.

8. The wireless access terminal of claim 2, wherein the controller is further configured to execute the program code to cause the wireless access terminal to provide feedback to the base transceiver station once in sixteen slots in the active hold state, and to provide feedback to the base transceiver station once in four slots in the traffic state.

9. The wireless access terminal of claim 1, wherein the controller is further configured to execute the program code to cause the wireless access terminal to transition from the dormant state to the active hold state in response to simultaneous presence of forward link traffic and absence of reverse link traffic.

10. A machine-readable medium comprising instructions, the instructions, when executed by at least one processor of a wireless access terminal for communicating with a base transceiver station of a radio network, cause the wireless access terminal to perform operations comprising:

initiating a transition from a traffic state to an active hold state in response to absence of reverse link traffic during a first predetermined time period,

initiating a transition from the active hold state to the traffic state in response to presence of reverse link traffic,

initiating a transition from the active hold state to the dormant state in response to absence of forward link traffic and reverse link traffic during at least a second predetermined period,

initiating a transition from the dormant state to the traffic state in response to presence of reverse link traffic,

after transitioning into the active hold state, remaining in the active hold state during simultaneous presence of forward link traffic and absence of reverse link traffic, and

in the active hold state, powering off at least one component of the transmitter so that duty cycle of said at least one component is less than twenty-five percent in the active hold state.

11. The machine-readable medium of claim 10, wherein the instructions, when executed by said at least one processor, further cause the wireless access terminal to perform operations comprising:

powering on said at least one component of the transmitter for at least a majority of time in the traffic state.

12. The machine-readable medium of claim 11, wherein the instructions, when executed by said at least one processor, further cause the wireless access terminal to perform operations comprising:

providing feedback to the base transceiver station in the active hold state, the step of providing feedback in the active hold state being performed with a first frequency; and

providing feedback to the base transceiver station in the traffic state, the step of providing feedback in the traffic state being performed with a second frequency, the second frequency being greater than the first frequency.

13. The machine-readable medium of claim 12, wherein the feedback comprises reverse link pilot and rate control.

14. The machine-readable medium of claim 10, wherein the instructions, when executed by said at least one processor, further cause the wireless access terminal to perform operations comprising:

transitioning from the dormant state to the active hold state in response to simultaneous presence of forward link traffic and absence of reverse link traffic.

15. A wireless access terminal for communicating with a base transceiver station of a radio network, the wireless access terminal comprising:

a means for receiving forward link transmissions from the base transceiver station;

a means for sending reverse link transmissions to the base transceiver station;

a means for storing program code; and

a controller means for executing the program code to cause the wireless access terminal to perform steps comprising;

initiating a transition from a traffic state to an active hold state in response to absence of reverse link traffic during a first predetermined time period,

initiating a transition from the active hold state to the traffic state in response to presence of reverse link traffic,

initiating a transition from the active hold state to a dormant state in response to absence of forward link traffic and reverse link traffic during at least a second predetermined period,

initiating a transition from the dormant state to the traffic state in response to presence of reverse link traffic,

after transitioning into the active hold state, remaining in the active hold state during simultaneous presence of forward link traffic and absence of reverse link traffic, and

powering off at least one component of the transmitter so that duty cycle of said at least one component is less than twenty-five percent in the active hold state.

16. A method of operating a wireless access terminal for communicating with a base transceiver station of a radio network, the method comprising:

initiating a transition from a traffic state to an active hold state in response to absence of reverse link traffic between the wireless access terminal and the base transceiver station during a first predetermined time period,

initiating a transition from the active hold state to the traffic state in response to presence of reverse link traffic between the wireless access terminal and the base transceiver station,

initiating a transition from the active hold state to the dormant state in response to absence of forward link traffic and reverse link traffic between the wireless access terminal and the base transceiver station during at least a second predetermined period,

initiating a transition from the dormant state to the traffic state in response to presence of reverse link traffic between the wireless access terminal and the base transceiver station,

after transitioning into the active hold state, causing the wireless access terminal to remain in the active hold state during simultaneous presence of forward link traffic and absence of reverse link traffic between the wireless access terminal and the base transceiver station, and

in the active hold state, powering off at least one component of a transmit chain of the wireless access terminal so that duty cycle of said at least one component is less than a predefined duty cycle threshold in the active hold state.

17. The method of claim 16, wherein the predefined duty cycle threshold is twenty-five percent.

18. The method of claim 17, further comprising:

causing the wireless access terminal to power on said at least one component of the transmitter for at least a majority of time in the traffic state.

19. The method of claim 18, further comprising:

providing feedback from the wireless access terminal to the base transceiver station in the active hold state, the step of providing feedback in the active hold state being performed with a first frequency; and

providing the feedback from the wireless access terminal to the base transceiver station in the traffic state, the step of providing feedback in the traffic state being performed with a second frequency, the second frequency being greater than the first frequency.

20. The method of claim 19, wherein the second frequency is at least twice the first frequency.

21. The method of claim 19, wherein the second frequency is at least four times the first frequency.

22. The method of claim 19, wherein the second frequency is about 150 Hertz, and the first frequency is about 75 Hertz.

23. The method of claim 19, wherein the second frequency is about 150 Hertz, and the first frequency is about 37.5 Hertz.

24. The method of claim 19, wherein the feedback comprises reverse link pilot and rate control.

25. The method of claim 19, wherein the feedback comprises data rate control (DRC).

26. The method of claim 19, wherein the feedback comprises data source control (DSC).

27. The method of claim 18, further comprising:

providing feedback from the wireless access terminal to the base transceiver station once in eight slots in the active hold state; and

providing feedback from the wireless access terminal to the base transceiver station once in four slots in the traffic state.

28. The method of claim 18, further comprising:

providing feedback from the wireless access terminal to the base transceiver station once in sixteen slots in the active hold state; and

providing feedback from the wireless access terminal to the base transceiver station once in four slots in the traffic state.

29. The method of claim 17, further comprising:

causing the wireless access terminal to transition from the dormant state to the active hold state in response to simultaneous presence of forward link traffic and absence of reverse link traffic.

30. The method of claim 17, wherein the step of initiating the transition from the traffic state to the active hold state comprises sending a spare reverse rate indicator (RRI) codeword to the base transceiver station.

31. The method of claim 30, further comprising:

receiving from the base transceiver station an acknowledgement of the spare RRI codeword; and

transitioning the wireless access terminal to the active hold state in response to the acknowledgement.

32. A method of operating a wireless access terminal for communicating with a base transceiver station of a radio network through a forward link and a reverse link, the method comprising:

step for causing the wireless access terminal to enter a dormant state in response to a period of traffic inactivity on the forward and reverse links between the wireless access terminal and the base transceiver station;

step for causing the wireless access device to enter a traffic state in response to traffic activity on the reverse link; and

step for causing the wireless access terminal to enter an active hold state in response to a period of traffic inactivity on the reverse links, the step for causing the wireless access terminal to enter the active hold state being performed regardless of traffic activity on the forward link, wherein the wireless access terminal in the active hold state powers on and off at least a portion of a transmit chain of the wireless access terminal with a duty cycle smaller than twenty-five percent.

33. A base transceiver station in a radio network, the base transceiver station comprising:

a receiver configured to receive data from a wireless access terminal on a reverse link;

a transmitter configured to transmit data to the wireless access terminal on a forward link; and

a processor coupled to the receiver and to the transmitter, wherein the processor is configured to cause the base transceiver station to perform steps comprising;

granting a request from the wireless access terminal to enter an active hold state, wherein the wireless access terminal generates the request in response to a period of traffic inactivity on the reverse link, and wherein the wireless access terminal decreases feedback update frequency for the forward link in the active hold state relative to a traffic state,

transmitting forward link traffic while the wireless access terminal is in the active hold state, and

receiving reverse link traffic in the traffic state.

34. The base transceiver station of claim 33, wherein the processor is further configured to cause the base transceiver station to vary power control set point of the wireless access terminal depending on state of the wireless access terminal, wherein the power control set point is higher in the active hold state than in the traffic state for the same signal to interference and noise ratio (SINR).

35. The base transceiver station of claim 33, wherein the processor is further configured to cause the base transceiver station to increase power control set point of the wireless access terminal when the wireless access terminal is in the active hold state and the power control set point is below a predetermined power limit.

36. The base transceiver station of claim 33, wherein the processor is further configured to cause the base transceiver station to vary power control set point of the wireless access terminal depending on the feedback update frequency.

37. A base transceiver station in a radio network, the base transceiver station comprising:

a means for receiving data from a wireless access terminal on a reverse link;

a means for transmitting data to the wireless access terminal on a forward link; and

a control means for processing, the control means being coupled to the receiver and to the transmitter, wherein the control means is configured to cause the base transceiver station to perform steps comprising;

granting a request from the wireless access terminal to enter an active hold state, wherein the wireless access terminal generates the request in response to a period of traffic inactivity on the reverse link, and wherein the wireless access terminal decreases feedback update frequency for the forward link while in the active hold state relative to a traffic state, and

transmitting forward link traffic while the wireless access terminal is in the active hold state.

38. A method of operating a base transceiver station in a radio network to control a wireless access terminal, the method comprising:

granting a request from the wireless access terminal to enter an active hold state, wherein the wireless access terminal generates the request in response to a period of traffic inactivity on a reverse link between the wireless access terminal and the base transceiver station, wherein the wireless access terminal in the active hold state provides feedback for a forward link between the wireless access terminal and the base transceiver station with a first frequency, and wherein the wireless access terminal provides feedback for the forward link in a traffic state with a second frequency, the second frequency being greater than the first frequency; and

transmitting traffic on the forward link while the wireless access terminal is in the active hold state.

39. A machine-readable medium comprising instructions, the instructions, when executed by at least one processor of a base transceiver station of a radio network, cause the base transceiver station to perform operations comprising:

granting a request from a wireless access terminal to enter an active hold state, wherein the wireless access terminal generates the request in response to a period of traffic inactivity on a reverse link between the wireless access terminal and the base transceiver station, wherein the wireless access terminal in the active hold state provides feedback for a forward link between the wireless access terminal and the base transceiver station with a first frequency, an wherein the wireless access terminal provides feedback for the forward link in a traffic state with a second frequency, the second frequency being greater than the first frequency; and

transmitting traffic on the forward link while the wireless access terminal is in the active hold state.