Method and apparatus for determining signatures for calibrating a communication station having an antenna array

• US 6,615,024 B1
• Filed: 04/20/1999
• Issued: 09/02/2003
• Est. Priority Date: 05/01/1998
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: ArrayComm LLC (Ygomi LLC)
• Inventors: Boros, Tibor, Barratt, Craig H., Uhlik, Christopher R., Trott, Mitchell D.
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): Moore, James K
• Application Number:
  US09/295,434
• Time in Patent Office: 1,596 Days
• Field of Search: 455/67.4, 455/562, 455/67.6, 455/69, 455/278.1, 455/101, 455/24, 455/25, 342/350, 342/354
• US Class Current: 455/67.14
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 17/10 of transmitters
• CPC Class Codes: H04B 17/11 for calibration
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase
• CPC Class Codes: H04B 17/14 of the whole transmission and reception path, e.g. self-test loop-back
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 7/005 Control of transmission; Equalising
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0842 Weighted combining
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

A method and apparatus for estimating the downlink signature for a remote transceiver which is part of a wireless communication system that includes a main transceiver for communicating with the remote transceiver. The main transceiver includes an array of transmit antenna elements. The method uses the remote transceiver for receiving signals when the main transceiver transmits downlink calibration signals. When the main transceiver also has a receive antenna array, the remote transceiver can transmit uplink calibration signals to the main transceiver for determining an uplink signature. The downlink and uplink signatures are used to determine a calibration function to account for differences in the apparatus chains that include the antenna elements of the arrays, and that enable downlink smart antenna processing weights to be determined from uplink smart antenna processing weights when the main transceiver includes means for smart antenna processing according to weights.

Claims

1. In a wireless communication system, a method comprising:

(a) transmitting a set of one or more downlink calibration waveforms from a main transceiver via an array of antenna elements of a transmit antenna array of the main transceiver to a remote transceiver, wherein the set of downlink calibration waveforms comprise modulated constant modulus calibration signals selected so that the dot product of any two calibration signals transmitted from any two distinct antenna elements of the transmit array is a pure tone;

(b) processing the signals received at the remote transceiver corresponding to the downlink calibration waveforms, the processing to determine downlink signature related signals related to the downlink signature for the remote transceiver, wherein the downlink signature related signals are determined in relation to a reference antenna element of the transmit antenna array;

(c) transmitting the downlink signature related signals from the remote transceiver to the main transceiver; and

(d) determining the downlink signature of the remote transceiver from the downlink signature related signals received at the main transceiver.

2. The method of claim 1, further comprising:

(e) transmitting a set of one or more uplink calibration waveforms from the remote transceiver to the main transceiver;

(f) processing at the main transceiver the received antenna signals corresponding to the uplink calibration signals transmitted from the remote transceiver, the processing determining the uplink signature for the remote transceiver; and

(h) determining a calibration function from the main transceiver from the uplink and downlink signatures for the remote transceiver.

3. The method of claim 2, wherein the uplink calibration signals are idle traffic waveforms.

4. The method of claim 2, wherein the uplink calibration signals are the downlink signature related signals.

5. The method of claim 2, further comprising:

(h) determining at the main transceiver an uplink weight vector for receiving from the remote transceiver by processing received antenna signals received while the remote transceiver is transmitting to the main transceiver; and

(j) determining at the main transceiver a downlink weight vector for transmitting to the remote transceiver from the determined uplink weights and the calibration function.

6. The method of claim 1, wherein each of the set of downlink calibration waveforms conform to an air interface standard.

7. The method of claim 1, wherein the downlink calibration waveforms are transmitted during silent periods.

8. The method of claim 1, wherein the downlink calibration waveforms are transmitted only after a number of idle waveforms are transmitted from the main transceiver.

9. The method of claim 1, wherein the downlink calibration waveforms transmitted from the main transceiver in step (a) are designed to be robust to one or more of the set comprising frequency offset, phase noise, I/Q mismatch, and timing offset.

10. The method of claim 1, wherein any component in a signature estimate is discarded if it corresponds to a weak receive or transmit antenna element relative to the other antenna elements.

11. The method of claim 1, wherein the downlink calibration waveforms are selected so that the signals transmitted from each transmit antenna element are substantially orthogonal.

12. The method of claim 11, wherein the downlink calibration waveforms comprise combinations of M distinct modulated constant modulus calibration signals, M being the number of antenna elements of the antenna array for which a downlink signature is being determined, each calibration signal comprising two segments, denoted a first segment and a second segment, respectively, the two segments being identically timed for each calibration signal, wherein during the first segment time interval, a first set of linear combinations of the calibration signals is transmitted from each of the antenna elements of the transmit array, and during the second segment time interval, a second set of linear combinations of the calibration signals is transmitted from each of the antenna elements of the transmit array.

13. The method of claim 11, wherein the signals transmitted from each antenna element of the transmit array are modulated tone signals, the frequencies of the tone signals from distinct arrays being distinct, the downlink signature related signal determining processing step and downlink signature determining step together comprising:

cross correlating the signals received at the remote transceiver with each of the tone signals, and

normalizing the correlations with the signal transmitted from the reference element.

14. The method of claim 11, wherein there are M antenna elements, the first set of linear combinations being a sum of M distinct tone signals being transmitted from the reference antenna element, and none of the tone signals being transmitted from the other transmit antenna elements, the frequencies of the tone of the distinct tone signals being distinct, the second set of linear combinations being a different one of the tone signals being transmitted from each of the antenna elements, the frequencies of the tones from the distinct arrays being distinct, wherein determining the downlink signature comprises:

cross correlating the signals received during a first segment at the remote transceiver with each of the first segment signals transmitted by each antenna element to obtain first segment correlations;

normalizing the first segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming first segment normalized correlations;

cross correlating the signals received during a second segment at the remote transceiver with each of the second segment signals transmitted by each antenna element to obtain second segment correlations;

normalizing the second segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming second segment normalized correlations; and

dividing each the second segment normalized correlation with the corresponding first segment normalized correlations to form the downlink signature estimate components.

15. The method of claim 1, where the downlink signature related signals comprise the downlink signature for the remote transceiver.

16. The method of claim 1, wherein the array of transmit antenna elements and the one or more receive antenna elements comprise common antenna elements.

17. The method of claim 1, wherein the downlink signature estimate is determined as the maximum likelihood estimate.

18. The method of claim 1, wherein the communication system is a cellular system comprising one or more base stations, each having one or more subscriber units, and wherein the main transceiver is one of the base stations.

19. The method of claim 18, wherein the remote transceiver is a subscriber unit of the main transceiver.

20. The method of claim 1, wherein the air interface standard is PHS.

21. The method of claim 1, wherein the at least one receive antenna element are a plurality of receive antenna elements forming an array of receive antenna elements, the number of elements in the array of receive antenna elements being the same as the number of antenna elements in the array of transmit antenna elements.

22. In a wireless communication system, a method comprising:

(a) transmitting a set of one or more downlink calibration waveforms from a main transceiver via an array of antenna elements of a transmit antenna array of the main transceiver to a remote transceiver;

(b) processing the signals received at the remote transceiver corresponding to the downlink calibration waveforms, the processing to determine downlink signature related signals related to a downlink signature for the remote transceiver;

(c) transmitting the downlink signature related signals from the remote transceiver to the main transceiver;

(d) transmitting a set of one or more uplink calibration signals from the remote transceiver to the main transceiver;

(e) processing at the main transceiver the received antenna signals corresponding to the uplink calibration signals transmitted from the remote transceiver, the processing determining an uplink signature for the remote transceiver;

(f) determining an uplink weight vector for the remote transceiver; and

(g) determining a downlink weight vector for the remote transceiver by;

(i) determining a calibration function for the remote transceiver from the determined uplink signature and the received antenna signals corresponding to the downlink signature related signals received at the main transceiver, and

(ii) determining the downlink weight vector from the determined uplink weight vector and the calibration function.

23. In a wireless communication system, a method comprising:

(a) transmitting a set of one or more downlink calibration waveforms from a main transceiver via an array of transmit antenna elements of a transmit antenna array of the main transceiver to a plurality of remote transceivers;

(b) processing the signals received at each remote transceiver corresponding to the downlink calibration waveforms, the processing to determine downlink signature related signals related to the downlink signature for each remote transceiver;

(c) transmitting the downlink signature related signals from each remote transceiver to the main transceiver;

(d) determining a downlink signature for each remote transceiver from the downlink signature related signals received at the main transceiver from each remote transceiver;

(e) combining the downlink signatures for each remote transceiver to determine a combined downlink signature,

(f) transmitting a set of one or more uplink calibration waveforms from each remote transceiver to the main transceiver;

(g) processing at the main transceiver the received antenna signals corresponding to the uplink calibration signals transmitted from each remote transceiver, the processing determining an uplink signature for each remote transceiver;

(h) combining the uplink signatures for the remote transceivers to determine a combined uplink signature;

(i) determining a calibration function for the main transceiver from the combined uplink and combined downlink signatures; and

(j) transmitting from each remote transceiver a remote transceiver received signal quality estimate to the main transceiver,

wherein the signature combining is a weighted combining, the weighting of the signature for each remote transceiver being the remote transceiver signal quality estimate of the remote transceiver.

24. The method of claim 23, wherein the main transceiver and the remote transceivers are designed for mutual communication using waveforms conforming to an air interface standard, and wherein each waveform in the set of downlink calibration waveforms substantially conforms to the air interface standard.

25. The method of claim 23, wherein the main transceiver comprises means for uplink adaptive smart antenna processing including linear uplink adaptive smart antenna processing according to an uplink weight vector, and downlink adaptive smart antenna processing including linear downlink adaptive smart antenna processing according to a downlink weight vector, the method further comprising:

(k) determining at the main transceiver the uplink weight vector for receiving from the subscriber unit by processing received antenna signals received while the remote transceiver is transmitting to the main transceiver; and

(l) determining at the main transceiver the downlink weight for transmitting to the remote transceiver from the determined uplink weights and the calibration factor.

26. The method of claim 23, wherein the signature combining is carried out by a principal component method.

27. The method of claim 23, wherein the at least one receive antenna element are a plurality of receive antenna elements forming an array of receive antenna elements, the number of elements in the array of receive antenna elements being the same as the number of antenna elements in the array of transmit antenna elements.

28. A wireless communication system comprising:

(a) a main transceiver comprising;

(i) an array of transmit antenna elements,

(ii) one or more receive antenna elements, and

(iii) one or more main transceiver signal processors for processing received antenna signals and for forming transmit apparatus signals; and

(b) a remote transceiver capable of receiving signals from and transmitting signals to the main transceiver comprising;

(i) a remote transceiver receive antenna for receiving remote transceiver received signals,

(i) a remote transceiver transmit antenna for transmitting remote transceiver transmit signals to the main transceiver, and

(iii) one or more remote transceiver signal processors for processing remote transceiver received signals and for forming remote transceiver transmit signals,

wherein at least one of the main transceiver signal processors is programmed to;

transmit a set of downlink calibration waveforms from the main transceiver via the transmit antenna array to the remote transceiver, wherein the downlink calibration waveforms comprise modulated constant modulus calibration signals selected so that the dot product of any two calibration signals transmitted from any two distinct antenna elements of the transmit array is a pure tone;

wherein at least one of the remote transceiver signal processors is programmed to;

process the signals received corresponding to the transmitted downlink calibration waveforms at the remote transceiver to determine downlink signature related signals related to the downlink signature for the remote transceiver, wherein the downlink signature is determined in relation to a reference antenna element of the transmit antenna array;

transmit the downlink signature related signals from the remote transceiver to the main transceiver, and

wherein at least one of the main transceiver signal processors is programmed to;

process the downlink signature related signals received at the main transceiver from the remote transceiver to determine the downlink signature for the remote transceiver.

29. The system of claim 28, wherein at least one of the remote transceiver signal processors is programmed to:

transmit a set of one or more uplink calibration waveforms to the main transceiver, and

wherein at least one of the main transceiver signal processors is programmed to;

process the received antenna signals corresponding to the uplink calibration waveforms transmitted from the remote transceiver, the processing determining an uplink signature for the remote transceiver; and

determine a calibration function for the main transceiver from the uplink and downlink signatures for the remote transceiver.

30. The system of claim 29, wherein the main transceiver further comprises means for uplink adaptive smart antenna processing including linear uplink adaptive smart antenna processing according to an uplink weight vector, and downlink adaptive smart antenna processing including linear downlink adaptive smart antenna processing according to a downlink weight vector, wherein at least one of the main transceiver signal processors is programmed to:

determine an uplink weight vector for receiving from the remote transceiver by processing received antenna signals received while the remote transceiver is transmitting to the main transceiver; and

determine the downlink weight for transmitting to the remote transceiver from the uplink weights determined for the remote transceiver and the calibration function.

31. The system of claim 29, wherein the uplink calibration signals are idle traffic waveforms.

32. The system of claim 29, wherein the uplink calibration signals are the downlink signature related signals.

33. The system of claim 28, the downlink calibration waveforms are selected so that the signals transmitted from each transmit antenna elements are substantially orthogonal.

34. The system of claim 28, wherein the downlink calibration waveforms are designed to be robust to one or more of the set comprising frequency offset, phase noise, I/Q mismatch, and timing offset.

35. The system of claim 28, wherein he downlink calibration waveforms comprise combinations of M distinct modulated constant modulus calibration signals, being the number of antenna elements of the antenna array for which a downlink signature is being determined, each calibration signal comprising two segments, denoted a first segment and a second segment, respectively, the two segments being identically timed for each calibration signal, wherein during the first segment time interval, a first set of linear combinations of the calibration signal is transmitted from each of the antenna elements of the transmit array, and during the second segment time interval, a second set of linear combinations of the calibration signals is transmitted from each of the antenna elements of the transmit array.

36. The system of claim 28, wherein the signals transmitted from each antenna element of the transmit array are modulated tone signals, the frequencies of the tone signals from distinct arrays being distinct, the downlink signature signals determining and the downlink signature determining together comprising:

cross correlating the signals received at the remote transceiver with each of the tone signals, and

normalizing the correlations with the signal transmitted from the reference element.

37. The system of claim 28, wherein there are M antenna elements, the first set of linear combinations being a sum of M distinct tone signals being transmitted from the reference antenna element, and none of the tone signals being transmitted from the other transmit antenna elements, the frequencies of the tone of the distinct tone signals being distinct, the second set of linear combinations being a different one of the tone signals being transmitted from each of the antenna element, the frequencies of the tones from the distinct arrays being distinct, the downlink signature signals determining and the downlink signature determining together comprising:

cross correlating the signals received during the first segment at the remote transceiver with each of the first segment signals transmitted by each antenna element to obtain first segment correlations;

normalizing the first segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming first segment normalized correlations;

cross correlating the signals received during the second segment at the remote transceiver with each of the second segment signals transmitted by each antenna element to obtain second segment correlations;

normalizing the second segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming second segment normalized correlations; and

dividing each the second segment normalized correlation with the corresponding first segment normalized correlations to form the downlink signature estimate components.

38. The system of claim 28, wherein the communication system is a cellular system comprising one or more base stations, each having one or more subscriber units, and wherein the main transceiver is one of the base stations.

39. The system of claim 28, wherein the remote transceiver is a subscriber unit of the main transceiver.

40. The system of claim 28, wherein the air interface standard is PHS.

41. The system of claim 28, where the downlink signature related signals comprise the downlink signature for the remote transceiver.

42. The system of claim 28, wherein the array of transmit antenna elements and the one or more receive antenna elements comprise common antenna elements.

43. The system of claim 28, wherein the downlink signature estimate is determined as the maximum likelihood estimate.

44. The system of claim 28, wherein the at least one receive antenna element are a plurality of receive antenna elements forming an array of receive antenna elements, the number of elements in the array of receive antenna elements being the same as the number of antenna elements in the array of transmit antenna elements.

45. In a wireless communication system, a method comprising:

(a) transmitting a set of one or more downlink calibration waveforms from a main transceiver via an array of antenna elements of a transmit antenna array of the main transceiver to a remote transceiver, wherein the downlink calibration waveforms comprise combinations of M distinct modulated constant modulus calibration signals, M being the number of antenna elements of the antenna array for which a downlink signature is being determined, each calibration signal comprising two segments, denoted a first segment and a second segment, respectively, the two segments being identically timed for each calibration signal, wherein during the first segment time interval, a first set of linear combinations of the calibration signals is transmitted from each of the antenna elements of the transmit array, and during the second segment time interval, a second set of linear combinations of the calibration signals is transmitted from each of the antenna elements of the transmit array;

(b) processing the signals received at the remote transceiver corresponding to the downlink calibration waveforms, the processing to determine downlink signature related signals related to the downlink signature for the remote transceiver;

(c) transmitting the downlink signature related signals from the remote transceiver to the main transceiver; and

(d) determining the downlink signature of the remote transceiver from the downlink signature related signals received at the main transceiver.

46. The method of claim 45, further comprising:

(e) transmitting a set of one or more uplink calibration waveforms from the remote transceiver to the main transceiver;

(f) processing at the main transceiver the received antenna signals corresponding to the uplink calibration signals transmitted from the remote transceiver, the processing determining the uplink signature for the remote transceiver; and

(h) determining a calibration function from the main transceiver from the uplink and downlink signatures for the remote transceiver.

47. The method of claim 45, wherein the downlink calibration waveforms are transmitted during silent periods.

48. The method of claim 45, wherein the downlink calibration waveforms are transmitted only after a number of idle waveforms are transmitted from the main transceiver.

49. The method of claim 45, wherein the downlink calibration waveforms transmitted from the main transceiver in step (a) are designed to be robust to one or more of the set comprising frequency offset, phase noise, I/Q mismatch, and timing offset.

50. The method of claim 45, wherein there are M antenna elements, the first set of linear combinations being a sum of M distinct tone signals being transmitted from the reference antenna element, and none of the tone signals being transmitted from the other transmit antenna elements, the frequencies of the tone of the distinct tone signals being distinct, the second set of linear combinations being a different one of the tone signals being transmitted from each of the antenna elements, the frequencies of the tones from the distinct arrays being distinct wherein determining the downlink signature comprises:

cross correlating the signals received during a first segment at the remote transceiver with each of the first segment signals transmitted by each antenna element to obtain first segment correlations;

normalizing the first segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming first segment normalized correlations;

cross correlating the signals received during a second segment at the remote transceiver with each of the second segment signals transmitted by each antenna element to obtain second segment correlations;

normalizing the second segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming second segment normalized correlations; and

dividing each the second segment normalized correlation with the corresponding first segment normalized correlations to form the downlink signature estimate components.

51. In a wireless communication system, a method comprising:

(a) transmitting a set of one or more downlink calibration waveforms from a main transceiver via an array of antenna elements of a transmit antenna array of the main transceiver to a remote transceiver, wherein the downlink calibration waveforms comprise modulated tone signals;

(b) processing the signals received at the remote transceiver corresponding to the downlink calibration waveforms, the processing to determine downlink signature related signals related to the downlink signature for the remote transceiver, wherein the downlink signature related waveforms are determined in relation to a reference antenna element by;

cross correlating the signals received at the remote transceiver with each of the tone signals, and

normalizing the correlations with the signal transmitted from the reference antenna element;

(c) transmitting the downlink signature related signals from the remote transceiver to the main transceiver; and

(d) determining the downlink signature of the remote transceiver from the downlink signature related signals received at the main transceiver.

52. The method of claim 51, further comprising:

(e) transmitting a set of one or more uplink calibration waveforms from the remote transceiver to the main transceiver;

(f) processing at the main transceiver the received antenna signals corresponding to the uplink calibration signals transmitted from the remote transceiver, the processing determining the uplink signature for the remote transceiver; and

(h) determining a calibration function from the main transceiver from the uplink and downlink signatures for the remote transceiver.

53. The method of claim 51, wherein the downlink calibration waveforms are transmitted during silent periods.

54. The method of claim 51, wherein the downlink calibration waveforms are transmitted only after a number of idle waveforms are transmitted from the main transceiver.

55. The method of claim 51, wherein the downlink calibration waveforms transmitted from the main transceiver in step (a) are designed to be robust to one or more of the set comprising frequency offset, phase noise, I/Q mismatch, and timing offset.

56. The method of claim 51, wherein there are M antenna elements, the first set of linear combinations being a sum of M distinct tone signals being transmitted from the reference antenna element, and none of the tone signals being transmitted from the other transmit antenna elements, the frequencies of the tone of the distinct tone signals being distinct, the second set of linear combinations being a different one of the tone signals being transmitted from each of the antenna elements, the frequencies of the tones from the distinct arrays being distinct wherein determining the downlink signature comprises:

cross correlating the signals received during a first segment at the remote transceiver with each of the first segment signals transmitted by each antenna element to obtain first segment correlations;

normalizing the first segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming first segment normalized correlations;

cross correlating the signals received during a second segment at the remote transceiver with each of the second segment signals transmitted by each antenna element to obtain second segment correlations;

normalizing the second segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming second segment normalized correlations; and

dividing each the second segment normalized correlation with the corresponding first segment normalized correlations to form the downlink signature estimate components.

57. A wireless communication system comprising:

(a) a main transceiver comprising;

(i) an array of transmit antenna elements,

(ii) one or more receive antenna elements, and

(iii) one or more main transceiver signal processors for processing received antenna signals and for forming transmit apparatus signals; and

(b) a remote transceiver capable of receiving signals from and transmitting signals to the main transceiver comprising;

(i) a remote transceiver receive antenna for receiving remote transceiver received signals,

(i) a remote transceiver transmit antenna for transmitting remote transceiver transmit signals to the main transceiver, and

(iii) one or more remote transceiver signal processors for processing remote transceiver received signals; and

for forming remote transceiver transmit signals,

wherein at least one of the main transceiver signal processors is programmed to;

transmit a set of downlink calibration waveforms from the main transceiver via the transmit antenna array to the remote transceiver,

wherein at least one of the remote transceiver signal processors is programmed to;

process the signals received corresponding to the transmitted downlink calibration waveforms at the remote transceiver to determine downlink signature related signals related to the downlink signature for the remote transceiver wherein the downlink signature related waveforms are determined in relation to a reference antenna element by;

cross correlating the signals received at the remote transceiver with each of the tone signals, and normalizing the correlations with the signal transmitted from the reference antenna element;

transmit the downlink signature related signals from the remote transceiver to the main transceiver, and

wherein at least one of the main transceiver signal processors is programmed to;

process the downlink signatures related at the main transceiver from the remote transceiver to determine the downlink signature for the remote transceiver.

58. The system of claim 57, wherein there are M antenna elements, the first set of linear combinations being a sum of M distinct tone signals being transmitted from the reference antenna element, and none of the tone signals being transmitted from the other transmit antenna elements, the frequencies of the tone of the distinct tone signals being distinct, the second set of linear combinations being a different one of the tone signals being transmitted from each of the antenna element, the frequencies of the tones from the distinct arrays being distinct, the downlink signature signals determining and the downlink signature determining together comprising:

cross correlating the signals received during the first segment at the remote transceiver with each of the first segment signals transmitted by each antenna element to obtain first segment correlations;

normalizing the first segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming first segment normalized correlations;

cross correlating the signals received during the second segment at the remote transceiver with each of the second segment signals transmitted by each antenna element to obtain second segment correlations;

normalizing the second segment correlations with the first segment correlation with the signal transmitted from the reference element, the normalizing forming second segment normalized correlations; and

dividing each the second segment normalized correlation with the corresponding first segment normalized correlations to form the downlink signature estimate components.

59. The system of claim 57, wherein at least one of the remote transceiver signal processors is programmed to:

transmit a set of one or more uplink calibration waveforms to the main transceiver, and

wherein at least one of the main transceiver signal processors is programmed to;

process the received antenna signals corresponding to the uplink calibration waveforms transmitted from the remote transceiver, the processing determining an uplink signature for the remote transceiver; and

determine a calibration function for the main transceiver from the uplink and downlink signatures for the remote transceiver.

60. The system of claim 57, wherein the main transceiver further comprises means for uplink adaptive smart antenna processing including linear uplink adaptive smart antenna processing according to an uplink weight vector, and downlink adaptive smart antenna processing including linear downlink adaptive smart antenna processing according to a downlink weight vector, wherein at least one of the main transceiver signal processors is programmed to:

determine an uplink weight vector for receiving from the remote transceiver by processing received antenna signals received while the remote transceiver is transmitting to the main transceiver; and

determine the downlink weight for transmitting to the remote transceiver from the uplink weights determined for the remote transceiver and the calibration function.