Multi-state power control mechanism for a wireless communication system

• US 6,876,866 B1
• Filed: 07/13/2000
• Issued: 04/05/2005
• Est. Priority Date: 07/13/2000
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ulupinar, Fatih, Esteves, Eduardo, Attar, Rashid
• Primary Examiner(s): APPIAH, CHARLES NANA
• Application Number:
  US09/615,355
• Time in Patent Office: 1,727 Days
• Field of Search: 455/522, 455/67.1, 455/69, 455/115, 370/318, 370/335, 370/342, 370/441, 370/127.1, 370/127.2
• US Class Current: 455/522
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/287 when the channel is in stand-by
• CPC Class Codes: H04W 52/288 taking into account the usage mode, e.g. hands-free, data transmission, telephone
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/44 in connection with interruption of transmission
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment

Abstract

A power control mechanism having a number of states and suitable for used in a communication system in which data transmissions are not continuous (i.e., bursty in nature). In one embodiment, a power control unit includes a data processor, a state machine, and a threshold adjustment element. The data processor receives and processes an input signal to provide status of data frames received from the input signal for a particular data transmission. The state machine receives the frame status and provides a current state for the power control unit. The current state is indicative of a status of a particular communication session that includes the data transmission, and is one of a number of possible states. The threshold adjustment element receives the frame status and the current state and adjusts a power control setpoint in response thereto. The setpoint is used to control the signal quality of the input signal and is adjusted in accordance with a particular adjustment scheme (i.e., a particular set of “rules”) selected from a number of possible adjustment schemes. Each possible adjustment scheme is associated with a respective possible state and defines a particular set of rules for adjusting the setpoint.

Claims

1. A power control unit for use in a wireless communication system, comprising:

a data processor operative to receive and process an input signal to provide status of frames of data received from the input signal for a particular data transmission;

a state machine operative to receive the frame status and provide a current state for the power control unit, wherein the current state is indicative of a status of a particular communication session comprising the data transmission, and wherein the current state is one of a plurality of possible states for the power control unit;

a threshold adjustment element operative to receive the frame status and the current state and to adjust a power control setpoint in response thereto for each frame period, and

wherein the setpoint is adjusted in accordance with a particular adjustment scheme selected from a plurality of possible adjustment schemes, and wherein each of the possible adjustment schemes corresponds to a respective one of the possible states and defines a particular set of rules for adjusting the setpoint.

2. The power control unit of claim 1, wherein the communication session is characterized by non-continuous data transmission comprising bursts of data transmission separated by periods of no transmission.

3. The power control unit of claim 1, wherein the current state is defined based, in part, on the frame status and a prior state.

4. The power control unit of claim 1, wherein each frame status indicates receipt of a good frame, a bad frame, or no received frame for a corresponding frame period.

5. The power control unit of claim 1, wherein the possible states includes an inactive state, a no data state, and a normal state.

6. The power control unit of claim 5, wherein the power control unit transitions from the inactive state to the no data state upon receipt of an indication of a change in a set of base stations involved in the communication session.

7. The power control unit of claim 5, wherein the power control unit transitions from the normal state to the no data state if no data frames are received for a particular time period.

8. The power control unit of claim 5, wherein the power control unit transitions from the no data state to the normal state upon receipt of a bad frame.

9. The power control unit of claim 5, wherein the power control unit transitions from the inactive state or the no data state to the inactive state upon receipt of an indication that no base stations are currently active in the communication session.

10. The power control unit of claim 5, wherein the setpoint is adjusted in a first direction by a first delta value (Δ

D₁) upon receipt of a frame status indicating a good frame, if the current state is the normal state.

11. The power control unit of claim 10, wherein the setpoint is adjusted in a second direction by a second delta value (Δ

U₁) upon receipt of a frame status indicating a bad frame, if the current state is the normal state, and wherein the second delta value (Δ

U₁) is greater in magnitude than the first delta value (Δ

D₁).

12. The power control unit of claim 11, wherein successive adjustments in the setpoint in the second direction is not performed while in the normal state unless a particular time period has elapsed.

13. The power control unit of claim 5, wherein the setpoint is adjusted in a second direction by a third delta value (Δ

U₂) upon receipt of a frame status indicating no received frame, if the current state is the no data state.

14. The power control unit of claim 13, wherein the adjustment in the setpoint in the second direction is limited to a particular maximum delta value (Δ

U_MAX) while the current state is the no data state.

15. The power control unit of claim 10, wherein the possible states further include a data start state.

16. The power control unit of claim 15, wherein the power control unit transitions from the no data state to the data start state upon receipt of a good frame.

17. The power control unit of claim 15, wherein the power control unit transitions from the data start state to the normal state upon receipt of a bad frame.

18. The power control unit of claim 15, wherein the setpoint is adjusted in the first direction by a fourth delta value (Δ

D₃) upon receipt of a frame status indicating a good frame, if the current state is the data start state, and wherein the fourth delta value (Δ

D₃) is greater in magnitude than the first delta value (Δ

D₁).

19. The power control unit of claim 1, further comprising a comparator configured to provide a power control command to adjust a transmit power level of a reverse link transmission from a remote terminal.

20. The power control unit of claim 1, wherein one or more frames are received for a particular transmitted data frame, and wherein the frame status corresponding to the transmitted frame is declared to be a good frame if at least one of the one or more received frames is determined to be a good frame.

21. The power control unit of claim 1, wherein one or more frames are received for a particular transmitted data frame, and wherein the frame status corresponding to the transmitted frame is declared to be a bad frame if all of the one or more received frames are determined to be bad frames.

22. The power control unit of claim 1, wherein the power control setpoint is further adjusted based on a particular target frame error rate (FER) for the received frames.

23. The power control unit of claim 1, wherein the power control setpoint is further adjusted based on a particular target erasure rate of packets transmitted along with the frames of data.

24. The power control unit of claim 23, wherein the setpoint is adjusted in a second direction by an effective delta value (Δ

U_EFF) upon receipt of a frame status indicating a bad frame, and wherein the effective delta value is adjusted based on an actual erasure rate of the packets.

25. The power control unit of claim 24, wherein effective delta value (Δ

U_EFF) is increased if the actual erasure rate of the packets is above a target value and decreased if the actual erasure rate is below the target value.

26. The power control unit of claim 1, wherein the data transmission comprises a reverse link data transmission in a CDMA communication system.

27. A method for providing power control of a transmitted signal in a wireless communication system, the method comprising:

receiving and processing the transmitted signal to provide status of frames of data received from the received and processed signal for a particular data transmission;

providing a current state for a power control mechanism, wherein the current state is indicative of a status of a particular communication session comprising the data transmission, and wherein the current state is one of a plurality of possible states for the power control mechanism;

adjusting a power control setpoint for each frame period in response to the frame status and the current state, wherein the setpoint is adjusted in accordance with a particular adjustment scheme selected from a plurality of possible adjustment schemes, and wherein each of the possible adjustment schemes corresponds to a respective one of the possible states and defines a particular set of rules for adjusting the setpoint.

28. The method of claim 27, wherein each frame status indicates receipt of a good frame, a bad frame, or no received frame for a corresponding frame period.

29. A base station in a wireless communication system, comprising:

an RF receiver unit operative to receive and modulated signal over a wireless communication link and to condition the received signal to generate a conditioned signal;

a channel processor operative to receive and process the conditioned signal to provide status of frames of data received from the modulated signal for a particular data transmission; and

a power control processor operative to receive the frame status and provide a power control setpoint in response thereto, wherein the power control processor includes;

a state machine operative to receive the frame status and provide a current state for the power control processor, wherein the current state is indicative of a status of a particular communication session comprising the data transmission, and wherein the current state is one of a plurality of possible states for the power control unit;

a threshold adjustment element operative to receive the frame status and the current state and to adjust the power control setpoint in response thereto for each frame period, wherein the setpoint is adjusted in accordance with a particular adjustment scheme selected from a plurality of possible adjustment schemes, and wherein each of the possible adjustment schemes corresponds to a respective one of the possible states and defines a particular set of rules for adjusting the setpoint.

30. The base station of claim 29, wherein the channel processor includes

signal quality measurement circuit operative to receive the conditioned signal and provide an indication of a signal quality of the conditioned signal, and

a data processor operative to receive, demodulate, and decode the conditioned signal to provide the frame status.