Method of self-calibration in a wireless transmitter

• US 20040198261A1
• Filed: 06/28/2002
• Published: 10/07/2004
• Est. Priority Date: 06/28/2002
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Xiong, Wei
• Application Number:
  US10/185,410
• Publication Number:
  US 20040198261A1
• Time in Patent Office: Days
• US Class Current: 455/115.1
• CPC Class Codes: H04B 17/13 of power amplifiers, e.g. gain or non-linearity
• 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 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A method of self-calibration of a wireless LAN communication device includes entering a self-calibration mode when the device is powered up or commanded by software. A packet stream is transmitted at an initial transmit power level. The packet stream may comprise standard data packets. The transmit power level may be monitored from data packet to data packet; and adjusted in steps by setting a transmit gain using a control voltage adjustment determined according to a transmit gain variation so as to make the step size as large as possible without exceeding a predetermined maximum step size. The transmit power level is, thus, adjusted so as not to exceed a predetermined maximum allowable level. The transmit power level is then adjusted to a desired level. Lower desired transmit power levels may be set by shifting bits in a digital-to-analog converter and setting the transmit gain for a higher transmit power level.

Claims

1. A method for self-calibration comprising steps of:

transmitting a transmit signal containing a packet stream at an initial transmit power level;

monitoring a transmit power level of said transmit signal;

adjusting said transmit power level of said transmit signal by a step size so as not to exceed a predetermined maximum allowable transmit power level; and

adjusting said transmit power level to a desired transmit power level.

2. The method of claim 1, further comprising a step of determining a control voltage adjustment according to a transmit gain variation so as to make said step size as large as possible without exceeding a predetermined maximum step size.

3. The method of claim 2 wherein said transmit gain variation comprises a part-to-part variation.

4. The method of claim 2 wherein said transmit gain variation comprises a variation due to changes in transmit frequency.

5. The method of claim 2 wherein said transmit gain variation comprises a supply voltage variation.

6. The method of claim 2 wherein said transmit gain variation comprises a variation due to changes in ambient temperature.

7. The method of claim 1 wherein said packet stream comprises at least one packet and said transmit power level of said transmit signal is monitored while said packet is being transmitted.

8. The method of claim 1 wherein said packet stream comprises a plurality of packets and said transmit power level of said transmit signal is monitored from packet to packet.

9. The method of claim 1 wherein said packet stream comprises an initially transmitted packet and said initially transmitted packet is a null packet.

10. The method of claim 1 wherein said packet stream comprises an initially transmitted packet and said initially transmitted packet is a standard data packet.

11. The method of claim 1 wherein said transmit power level is adjusted to a desired transmit power level by linear extrapolation using a linearizer table.

12. The method of claim 1 wherein said transmit power level is adjusted to a lower desired transmit power level by shifting bits in a digital-to-analog converter and setting a transmit gain for a higher transmit power level.

13. The method of claim 1 wherein an error value is saved in a lookup table and a gain control is offset with said error value to compensate for a part-to-part variation, thereby reducing a worst case number of times said step of adjusting said transmit power level of said transmit signal by a step size is performed.

14. The method of claim 1, further comprising a step of entering a self-calibration mode when a wireless communication device is powered up and periodically at a predetermined time interval thereafter.

15. The method of claim 1, further comprising a step of exiting a self-calibration mode after said step of adjusting said transmit power level to a desired transmit power level.

16. The method of claim 1 wherein said predetermined maximum allowable transmit power level is in accordance with an 802.11b standard.

17. A method of self-calibration of a wireless communication device comprising steps of:

determining a control voltage adjustment according to a transmit gain variation so as to make a step size as large as possible without exceeding a predetermined maximum step size;

entering a self-calibration mode when said wireless communication device is powered up;

transmitting a transmit signal containing a packet stream at an initial transmit power level;

monitoring a transmit power level of said transmit signal;

using said control voltage adjustment to adjust said transmit power level of said transmit signal by said step size so as not to exceed a predetermined maximum allowable transmit power level; and

adjusting said transmit power level to a desired transmit power level.

18. The method of claim 17 wherein said packet stream comprises a packet and said transmit power level of said transmit signal is monitored while said packet is being transmitted.

19. The method of claim 17 wherein said packet stream comprises a plurality of packets and said transmit power level of said transmit signal is monitored from packet to packet.

20. The method of claim 17 wherein said packet stream comprises an initially transmitted packet and said initially transmitted packet is a null packet.

21. The method of claim 17 wherein said packet stream comprises an initially transmitted packet and said initially transmitted packet is a standard data packet.

22. The method of claim 17 wherein said transmit power level is adjusted to a desired transmit power level by linear extrapolation using a linearizer table.

23. The method of claim 17 wherein said transmit power level is adjusted to a lower desired transmit power level by shifting bits in a digital-to-analog converter and setting a transmit gain for a higher transmit power level.

24. The method of claim 17 wherein an error value is saved in a lookup table and a gain control is offset with said error value to compensate for a part-to-part variation, thereby reducing a worst case number of times said step of adjusting said transmit power level of said transmit signal by a step size is performed.

25. The method of claim 17, further comprising a step of exiting a self-calibration mode after said step of adjusting said transmit power level to a desired transmit power level.

26. The method of claim 17 wherein said predetermined maximum allowable transmit power level is in accordance with an 802.11b standard.

27. A method of self-calibration of a wireless LAN communication device for communication with an access point of a LAN, comprising steps of:

entering a self-calibration mode when said wireless LAN communication device is powered up;

transmitting a transmit signal containing a packet stream at an initial transmit power level, wherein said packet stream comprises at least one packet;

monitoring a transmit power level of said transmit signal, wherein said transmit power level of said transmit signal is monitored from packet to packet;

adjusting said transmit power level of said transmit signal by a step size so as not to exceed a predetermined maximum allowable transmit power level; and

adjusting said transmit power level to a desired transmit power level.

28. The method of claim 27, further comprising a step of determining a control voltage adjustment according to a transmit gain variation so as to make said step size as large as possible without exceeding a predetermined maximum step size.

29. The method of claim 27 wherein said packet stream comprises an initially transmitted packet and said initially transmitted packet is a null packet.

30. The method of claim 27 wherein said packet stream comprises an initially transmitted packet and said initially transmitted packet is a standard data packet.

31. The method of claim 27 wherein said transmit power level is adjusted to a lower desired transmit power level by shifting bits in a digital-to-analog converter and setting a transmit gain for a higher transmit power level.

32. The method of claim 27 wherein an error value is saved in a lookup table and a gain control is offset with said error value to compensated for a part-to-part variation, thereby reducing a worst case number of times said step of adjusting said transmit power level of said transmit signal by a step size is performed.

33. The method of claim 27, further comprising a step of exiting a self-calibration mode after said step of adjusting said transmit power level to a desired transmit power level.

34. The method of claim 27 wherein said predetermined maximum allowable transmit power level is in accordance with an 802.11b standard.

35. A method of self-calibration of a wireless LAN communication device for communication with an access point of a LAN, comprising steps of:

entering a self-calibration mode when said wireless LAN communication device is powered up;

transmitting a transmit signal containing a packet stream at an initial transmit power level, wherein said packet stream comprises at least one standard data packet;

monitoring a transmit power level of said transmit signal, wherein said transmit power level of said transmit signal is monitored from packet to packet.

adjusting said transmit power level of said transmit signal by a step size, wherein said adjusting is performed by setting a transmit gain using a control voltage adjustment determined according to a transmit gain variation so as to make said step size as large as possible without exceeding a predetermined maximum step size, whereby said transmit power level is adjusted so as not to exceed a predetermined maximum allowable transmit power level in accordance with a 802.11b standard; and

adjusting said transmit power level to a desired transmit power level, wherein said transmit power level is adjusted to a higher desired transmit power level by setting said transmit gain for said higher desired transmit power level, and wherein said transmit power level is adjusted to a lower desired transmit power level by shifting bits in a digital-to-analog converter and setting said transmit gain for a higher transmit power level.

36. The method of claim 35 wherein an error value is saved in a lookup table and a gain control is offset with said error value to compensated for a part-to-part variation, thereby reducing a worst case number of times said step of adjusting said transmit power level of said transmit signal by a step size is performed.

37. A transmitter comprising:

a variable gain amplifier having a gain controlled by a control voltage;

a power detector for monitoring a transmit power level of said transmitter and converting said transmit power level to a measurement voltage;

an analog-to-digital converter for converting said measurement voltage to a digital value;

a baseband processor, said baseband processor receiving said digital value and producing said control voltage while providing an output signal comprising a packet stream to said variable gain amplifier, wherein said baseband processor adjusts said control voltage during transmission of said packet stream, said control voltage effecting an adjustment to said transmit power level via said variable gain amplifier, said adjustment made from an initial transmit power level by a step size so as not to exceed a predetermined maximum allowable transmit power level; and

wherein said baseband processor adjusts said control voltage so as to adjust said transmit power level to a desired transmit power level.

38. The transmitter of claim 37, wherein said adjustment is determined according to a transmit gain variation so as to make said step size as large as possible without exceeding a predetermined maximum step size.

39. The transmitter of claim 38 wherein said transmit gain variation comprises a part-to-part variation.

40. The transmitter of claim 38 wherein said transmit gain variation comprises a variation due to changes in transmit frequency.

41. The transmitter of claim 38 wherein said transmit gain variation comprises a supply voltage variation.

42. The transmitter of claim 38 wherein said transmit gain variation comprises a variation due to changes in ambient temperature.

43. The transmitter of claim 37 wherein an error value is saved in a lookup table and a gain control is offset with said error value to compensate for a part-to-part variation, thereby reducing a worst case number of times said adjustment to said transmit power level by a step size is made.

44. The transmitter of claim 37 wherein said predetermined maximum allowable transmit power level is in accordance with an 802.11b standard.

45. The transmitter of claim 37 wherein said transmit power level is adjusted to a lower desired transmit power level by shifting bits in a digital-to-analog converter and setting a transmit gain for a higher transmit power level.

46. The transmitter of claim 37 wherein said packet stream comprises at least one packet and said control voltage is adjusted while said packet is being transmitted.

47. The transmitter of claim 37 wherein said packet stream comprises a plurality of packets and said control voltage is adjusted from packet to packet.

48. The transmitter of claim 37 wherein said packet stream comprises an initially transmitted packet and said initially transmitted packet is a null packet.

49. The transmitter of claim 37 wherein said packet stream comprises an initially transmitted packet and said initially transmitted packet is a standard data packet.

50. The transmitter of claim 37 wherein said transmit power level is adjusted to a desired transmit power level by linear extrapolation using a linearizer table.

51. A wireless communication device comprising a transmitter and a receiver, said transmitter comprising:

a variable gain amplifier having a gain controlled by a control voltage;

a power detector for monitoring a transmit power level of said transmitter and converting said transmit power level to a measurement voltage;

an analog-to-digital converter for converting said measurement voltage to a digital value;

a baseband processor, said baseband processor receiving said digital value and producing said control voltage while providing an output signal comprising a packet stream to said variable gain amplifier, wherein said baseband processor adjusts said control voltage during transmission of said packet stream, said control voltage effecting an adjustment to said transmit power level via said variable gain amplifier, said adjustment made from an initial transmit power level by a step size so as not to exceed a predetermined maximum allowable transmit power level; and

wherein said baseband processor adjusts said control voltage so as to adjust said transmit power level to a desired transmit power level.

52. The wireless communication device of claim 51, wherein said adjustment is determined according to a transmit gain variation so as to make said step size as large as possible without exceeding a predetermined maximum step size.

53. The wireless communication device of claim 52 wherein said transmit gain variation comprises a part-to-part variation.

54. The wireless communication device of claim 53 wherein an error value is saved in a lookup table and a gain control is offset with said error value to compensate for a part-to-part variation, thereby reducing a worst case number of times said adjustment to said transmit power level by a step size is made.

55. The wireless communication device of claim 51 wherein said predetermined maximum allowable transmit power level is in accordance with an 802.11b standard.

56. The wireless communication device of claim 51 wherein said transmit power level is adjusted to a lower desired transmit power level by shifting bits in a digital-to-analog converter and setting a transmit gain for a higher transmit power level.

57. The wireless communication device of claim 51 wherein said packet stream comprises a plurality of packets and said control voltage is adjusted from packet to packet.

58. A communication system comprising:

a local area network having an access point;

a wireless communication device for communication with said local area network via said access point, wherein said wireless communication device comprises a transmitter and a receiver, said transmitter comprising;

a variable gain amplifier having a gain controlled by a control voltage;

a power detector for monitoring a transmit power level of said transmitter and converting said transmit power level to a measurement voltage;

an analog-to-digital converter for converting said measurement voltage to a digital value;

a baseband processor, said baseband processor receiving said digital value and producing said control voltage while providing an output signal comprising a packet stream to said variable gain amplifier, wherein said baseband processor adjusts said control voltage during transmission of said packet stream, said control voltage effecting an adjustment to said transmit power level via said variable gain amplifier, said adjustment made from an initial transmit power level by a step size so as not to exceed a predetermined maximum allowable transmit power level; and

wherein said baseband processor adjusts said control voltage so as to adjust said transmit power level to a desired transmit power level.

59. The communication system of claim 58, wherein said adjustment is determined according to a transmit gain variation so as to make said step size as large as possible without exceeding a predetermined maximum step size.

60. The communication system of claim 59 wherein said transmit gain variation comprises a part-to-part variation.

61. The communication system of claim 60 wherein an error value is saved in a lookup table and a gain control is offset with said error value to compensate for a part-to-part variation, thereby reducing a worst case number of times said adjustment to said transmit power level by a step size is made.

62. The communication system of claim 58 wherein said predetermined maximum allowable transmit power level is in accordance with an 802.11b standard.

63. The communication system of claim 58 wherein said transmit power level is adjusted to a lower desired transmit power level by shifting bits in a digital-to-analog converter and setting a transmit gain for a higher transmit power level.

64. The communication system of claim 58 wherein said packet stream comprises a plurality of packets and said control voltage is adjusted from packet to packet.