POWER EFFICIENT COMMUNICATIONS

• US 20110223874A1
• Filed: 03/11/2011
• Published: 09/15/2011
• Est. Priority Date: 03/12/2010
• Status: Active Grant

• Current Assignee: Sunrise Micro Devices, Inc. (SoftBank Group Corp.)
• Original Assignee: Sunrise Micro Devices, Inc. (SoftBank Group Corp.)
• Inventors: Gorday, Paul E., Callaway, Edgar H. JR.
• Granted Patent: US 9,198,133 B2
• Time in Patent Office: Days
• US Class Current: 455/115.3
• CPC Class Codes: G05F 1/66 Regulating electric power
• CPC Class Codes: H04B 1/3883 Arrangements for mounting batteries or battery chargers
• CPC Class Codes: H04L 27/2614 Peak power aspects
• CPC Class Codes: H04L 47/748 Negotiation of resources, e.g. modification of a request
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 52/0261 managing power supply demand, e.g. depending on battery level
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method, system, and device provide power-efficient communications within the context of available power. Transmission and receipt data rates are scalable in accordance with output power available from a power source. Data is transmitted at a data rate determined, at least in part, by the available output power.

Claims

1. A power-efficient communication device, comprising:

a transmitter capable of a data transmission rate determined, at least in part, by output power available to the transmitter from an electrical power source.

2. The device of claim 1, wherein the data transmission rate is determined such that a transmission range of the transmitter is constant as the available output power varies.

3. The device of claim 1, wherein a ratio of peak-to-average power consumed by the transmitter to transmit the data is minimized in order to maximize a portion of the available output power used by the transmitter to transmit.

4. The device of claim 3, wherein minimization of the ratio of peak-to-average power consumed by the transmitter provides for an increased data transmission rate.

5. The device of claim 3, wherein minimization of the ratio of peak-to-average power consumed by the transmitter increases a transmission range of the transmitter.

6. The device of claim 3, wherein minimization of the ratio of peak-to-average power consumed by the transmitter provides for the power used by the transmitter to transmit the data to be reduced.

7. The device of claim 6, wherein the data transmission rate is increased.

8. The device of claim 6, wherein a transmission range of the transmitter is increased.

9. The device of claim 6, wherein the transmitter further comprises:

a synthesizer;

a controlled oscillator; and

a sequencer operable to generate a plurality of enable signals that control operation of the synthesizer, the controlled oscillator, and a transmit signal path of the transmitter,

wherein the sequencer is operable to selectively control operation of the transmitter to prevent simultaneous operation of the synthesizer and the transmit signal path during a transmit period of the transmitter.

10. The device of claim 9, wherein the sequencer operable to generate a first enable signal that enables the synthesizer, a second enable signal that enables the controlled oscillator, and a third enable signal that enables the transmit signal path of the transmitter and wherein during a warm-up period of the transmitter the sequencer is operable to activate the first enable signal to enable the synthesizer and the second enable signal to enable the controlled oscillator, wait until the synthesizer is locked, and deactivate the first enable signal and activate the third enable signal to, enable the transmit signal path during the transmit period of the transmitter, and deactivate the second enable signal and the third enable signal following the transmit period of the transmitter.

11. The device of claim 6, wherein the transmitter is operable to reduce the power used by the transmitter to transmit the data by selective control of the operation of a microcomputer and the transmitter to prevent simultaneous operation of the microcomputer and the transmitter during a transmit period of the transmitter.

12. The device of claim 11, wherein the microcomputer places a prepared data packet in a transmit buffer while the transmitter is in a transmitter sleep mode and goes into a microcomputer sleep mode after placement of the prepared data packet in the transmit buffer and herein the transmitter wakes up and transmits the prepared data packet and returns to the transmitter sleep mode following transmittal of the prepared data packet.

13. The device of claim 1, wherein the electrical power source is a battery, the available output power of the battery is below a threshold, and the transmitter has a transmission range and wherein the transmission range of the transmitter is maintained when the available output power of the batter is below the threshold by lowering a transmit power of the transmitter and lowering the data transmission rate to a new lower data transmission rate.

14. The device of claim 1, wherein the transmitter is operable to predict a future value of the available output power and in accordance with the predicted change in available output power to change one or more of the transmit power of the transmitter and the data transmission rate of the transmitter.

15. The device of claim 14, wherein prior to transmitting data the transmitter is operable to change one or more of the transmit power of the transmitter and a data transmission rate of the transmitter in accordance with the predicted future value of the available output power of the electrical power source.

16. The device of claim 15, wherein the transmitter is further operable to notify a receiver of the changed data transmission rate of the transmitter.

17. The device of claim 14, wherein the transmitter predicts a future value of the available output power of the electrical power source using a plurality of prior values of the available output power of the electrical power source.

18. The device of claim 14, wherein the transmitter predicts a future value of the available output power of the electrical power source using a predictive algorithm comprising one or more of a curve-fitting technique, a linear extrapolation, a non-linear extrapolation, and a heuristic.

19. The device of claim 18, wherein in accordance with the predictive algorithm, the transmitter is operable to collect at a plurality of times T₋

n the available output power P<sub>−

n</sub> of the electrical power source, determine a linear rate of change m of the available output power in accordance with

20. The device of claim 1, wherein to optimize the data transmission rate over a communication link the transmitter is operable to transmit a plurality of consecutive data packets over the communication link at a test data transmission rate and determine whether each data packet of the plurality of consecutive data packets was successfully transmitted at the test data transmission rate,

wherein if each data packet of the plurality of consecutive data packets were successfully transmitted at the test data transmission rate, the transmitter is operable to increase the test data transmission rate by a predetermined multiplier to an increased test data transmission rate if the test data transmission rate is not a maximum data transmission rate of the communication link and

wherein if one or more of the data packets of the plurality of consecutive data packets were not successfully transmitted at the test data transmission rate, then upon determination that a first data packet of the one or more of the data packets of the plurality of consecutive data packets was not successfully transmitted the transmitter is operable to reduce the test data transmission rate by a predetermined divider to a reduced test data transmission rate and transmit the first data packet of the one or more data packets of the plurality of consecutive data packets at the reduced test data transmission rate.

21. The device of claim 20, wherein the transmitter determines whether the plurality of consecutive data packets were successfully transmitted by determining whether an acknowledge message is received for each data packet of the plurality of consecutive data packets transmitted.

22. The device of claim 20, wherein before transmitting the plurality of data packets over the communication link, the transmitter is operable to determine a maximum data transmission rate of the communication link and transmit the plurality of data packets over the communication link at the maximum determined data transmission rate.

23. The device of claim 1, wherein the device is a transceiver further comprising:

a receiver operable to receive data at a data reception rate determined, at least in part, by the output power available from the electrical power source.

24. A method of power-efficient communications, comprising:

determining an available output power of an electrical power source; and

transmitting data at a data transmission rate determined, at least in part, by the available output power.

25. The method of claim 24, further comprising:

minimizing a ratio of peak-to-average power consumed in transmitting the data in order to maximize a portion of the available output power usable to transmit data.

26. The method of claim 25, wherein minimizing the ratio of peak-to-average power provides for increasing one or more of the data transmission rate and a transmission range.

27. The method of claim 25, wherein minimizing the ratio of peak-to-average power further comprises:

reducing power consumption of a transmitter that transmits the data.

28. The method of claim 27, further comprising increasing the data transmission rate of the transmitter.

29. The method of claim 27, further comprising increasing a transmission range of the transmitter.

30. The method of claim 27, wherein reducing the power used by the transmitter to transmit the data further comprises:

selectively controlling operation of the transmitter to minimize the ratio of peak-to-average power used by a synthesizer and a transmit signal path of the transmitter during a transmit period of the transmitter.

31. The method of claim 27, wherein reducing the power used by the transmitter to transmit the data further comprises:

selectively controlling operation of a microcomputer and the transmitter to minimize the ratio of peak-to-average power used by the microcomputer and the transmitter.

32. The method of claim 31, further comprising:

the microcomputer placing a prepared data packet in a transmit buffer of the transmitter while the transmitter is in a transmitter sleep mode;

the microcomputer going into a microcomputer sleep mode;

the transmitter waking up and transmitting the prepared data packet in the transmit buffer; and

following transmittal of the prepared data packet, the transmitter going into the transmitter sleep mode.

33. The method of claim 24, further comprising:

determining a data reception rate of data transmitted by a first network device and received by a second network device; and

estimating a range between said first and second network devices from the data reception rate.

34. The method of claim 33, wherein the range is further determined from an estimated transmit power of the first network device.

35. The method of claim 33, wherein an RSSI value is not needed to estimate the range.

36. The method of claim 24, wherein the electrical power source is a battery, the available output power of the battery is below a threshold, and a transmitter that transmits the data has a transmission range, the method further comprising:

lowering a transmit power of the transmitter and lowering the data transmission rate of the transmitter to a new lower data transmission rate to maintain the transmission range of the transmitter.

37. The method of claim 36, wherein lowering the data transmission rate to the new lower data transmission rate occurs prior to lowering the transmit power of the transmitter.

38. The method of claim 37, wherein prior to lowering the transmit power but after lowering the data transmission rate, increasing the transmission range of the transmitter.

39. The method of claim 24, wherein determining available output power of the electrical power source comprises predicting a future value of the available output power of the electrical power source.

40. The method of claim 39, further comprising prior to transmitting data:

changing one or more of the transmit power of a transmitter and a data transmission rate of the transmitter in accordance with the predicted future value of the available output power of the electrical power source.

41. The method of claim 40, further comprising:

notifying a receiver of the changed data transmission rate of the transmitter.

42. The method of claim 39, wherein predicting a future value of the available output power of the electrical power source further comprises using a plurality of prior values of the available output power of the electrical power source.

43. The method of claim 39, wherein predicting a future value of the available output power of the electrical power source further comprises the use of a predictive algorithm having one or more of a curve-fitting technique, a linear extrapolation, a non-linear extrapolation, and a heuristic.

44. The method of claim 43, wherein in accordance with the predictive algorithm, further comprising:

a transmitter collecting at a plurality of times T<sub>−

n</sub> the available output power P<sub>−

n</sub> of the electrical power source;

determining a linear rate of change m of the available output power in accordance with

45. The method of claim 24, further comprising optimizing the data transmission rate over a communication link, comprising:

transmitting a plurality of consecutive data packets over the communication link at a test data transmission rate;

determining whether each data packet of the plurality of consecutive data packets was successfully transmitted at the test data transmission rate;

if each data packet of the plurality of consecutive data packets were successfully transmitted at the test data transmission rate, increasing the test data transmission rate by a predetermined multiplier to an increased test data transmission rate if the test data transmission rate is not a maximum data transmission rate of the communication link; and

if one or more of the data packets of the plurality of consecutive data packets were not successfully transmitted at the test data transmission rate, then upon determination that a first data packet of the one or more of the data packets of the plurality of consecutive data packets was not successfully transmitted reducing the test data transmission rate zo by a predetermined divider to a reduced test data transmission rate and transmitting the first data packet of the one or more data packets of the plurality of consecutive data packets at the reduced test data transmission rate.

46. The method of claim 45, wherein determining whether the plurality of consecutive data packets were successfully transmitted comprises determining whether an acknowledge message is received for each data packet of the plurality of consecutive data packets transmitted.

47. The method of claim 45, further comprising prior to the transmitting the plurality of data packets over the communication link:

determining a maximum data transmission rate of the communication link; and

transmitting the plurality of data packets over the communication link at the maximum determined data transmission rate.