Method and apparatus for estimating reverse link loading in a wireless communication system

• US 6,397,070 B1
• Filed: 07/21/1999
• Issued: 05/28/2002
• Est. Priority Date: 07/21/1999
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Black, Peter J.
• Primary Examiner(s): Legree, Tracy
• Application Number:
  US09/358,088
• Time in Patent Office: 1,042 Days
• Field of Search: 455/446,453,67.1,67.3,522,69,70,92,302,307,296 370/249,335,342,331,332 333/167,174,176,178,181,182,207,208
• US Class Current: 455/453
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level

Abstract

Method and apparatus for estimating reverse link loading in a wireless communication system. In the present invention, the reverse link signals are passed through notch filters such that no energy (or energy of negligible amounts) is transmitted in these areas of the reverse link frequency band. At the base station, the unloaded cell energy is estimated by measuring the energy in the areas where the reverse link signals are notched. The in band energy is then compared to the energy in the notched portions of the reverse link band and based on this ratio cell capacity is determined.

Claims

1. A method for estimating a reverse link loading in a wireless communication system comprising the steps of:

(a) transmitting from a remote station a signal containing negligible energy in at least a first portion of a reverse link frequency band;

(b) measuring, at a base station, a first energy in a second portion of said reverse link frequency band, said second portion containing said first portion;

(c) measuring, at said base station, a second energy in said reverse link frequency band; and

(d) computing, at said base station, said reverse link loading utilizing said first energy and said second energy.

2. The method in accordance with claim 1 wherein a position of said portion within said reverse link frequency band is invariable with time.

3. The method in accordance with claim 1 wherein a position of said portion within said reverse link frequency band is variable with time.

4. The method in accordance with claim 3 wherein said variation with time is continuous in time.

5. The method in accordance with claim 3 wherein said variation with time is discontinuous in time.

6. The method in accordance with claim 1 wherein the step of transmitting from a remote station a signal comprises the steps of:

(a) generating, at said remote station, said signal to be transmitted;

(b) filtering, at said remote station, said signal by a notch filter; and

(c) transmitting from said remote station said filtered signal.

7. The method in accordance with claim 1 wherein the step of measuring, at a base station, a first energy comprises the steps of:

(a) filtering, at said base station, said reverse link frequency band by a band-pass filter; and

(b) measuring, at said base station, said first energy of said filtered reverse link frequency band.

8. The method in accordance with claim 1 wherein the step of computing, said reverse link loading proceeds in accordance with an equation:

$\mathrm{RLL}=\frac{I_o}{\left[I_{\mathrm{Notch}}-2<br><br>I_O<br><br>\left(\frac{B_{\mathrm{Bandpass}}-B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}\right)\right]}<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band;

(iv) B_Notch is said first portion of said reverse link frequency band; and

(v) B_Bandpass is said second portion of said reverse link frequency band.

9. The method in accordance with claim 1 wherein the step of computing, said reverse link loading proceeds in accordance with an equation:

$\mathrm{RLL}=\frac{I_O}{I_{\mathrm{Notch}}}·<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) M_Notch is said first energy;

(iii) B_Total is said reverse link frequency band; and

(iv) B_Notch is said first portion of said reverse link frequency band.

10. The method in accordance with claim 1 wherein said wireless communication system is a spread spectrum wireless system.

11. The method in accordance with claim 10 wherein said spread spectrum wireless communication system is a direct sequence spread spectrum wireless system.

12. The method in accordance with claim 10 wherein said spread spectrum wireless communication system is a frequency hopped spread spectrum wireless system.

13. A Method for producing, at a remote station, a signal to be used for estimating a reverse link loading comprising the steps of:

(a) generating, at said remote station, a signal to be transmitted; and

(b) filtering, at said remote station, said signal by a notch filter, wherein a position of said notch within a reverse link frequency band is invariable with time.

14. A method for producing, at a remote station, a signal to be used for estimating a reverse link loading comprising the steps of:

(a) generating, at said remote station, a signal to be transmitted; and

(b) filtering, at said remote station, said signal by a notch filter, wherein a position of said notch within a reverse link frequency band is variable with time.

15. The method in accordance with claim 14 wherein said variation with time is continuous in time.

16. The method in accordance with claim 14 wherein said variation with time is discontinuous in time.

17. A method for estimating a reverse link loading by a base station comprising the steps of:

(a) receiving, at said base station, a reverse link signal containing negligible energy in at least a first portion of a reverse link frequency band

(b) measuring, at said base station, a first energy in a second portion of said reverse link frequency band, said second portion containing said first portion;

(c) measuring, at said base station, a second energy in said reverse link frequency band; and

(d) computing, at said base station, said reverse link loading utilizing said first energy and said second energy.

18. The method in accordance with claim 17 wherein the step of measuring, at a base station, a first energy comprises the steps of:

(a) filtering, at said base station, said reverse link frequency band by a band-pass filter; and

(b) measuring, at said base station, said first energy of said filtered reverse link frequency band.

19. The method in accordance with claim 17 wherein the step of computing, said reverse link loading proceeds in accordance with an equation:

$\mathrm{RLL}=\frac{I_o}{\left[I_{\mathrm{Notch}}-2<br><br>I_O<br><br>\left(\frac{B_{\mathrm{Bandpass}}-B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}\right)\right]}<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band;

(iv) B_Notch is said first portion of said reverse link frequency band; and

(v) B_Bandpass is said second portion of said reverse link frequency band.

20. The method in accordance with claim 17 wherein the step of computing, said reverse link loading proceeds in accordance with an equation:

$\mathrm{RLL}=\frac{I_O}{I_{\mathrm{Notch}}}·<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band; and

(iv) B_Notch is said first portion of said reverse link frequency band.

21. An apparatus for estimating a reverse link loading in a wireless communication system comprising:

(a) means for transmitting from a remote station a signal containing negligible energy in at least a first portion of a reverse link frequency band;

(b) means for measuring, at a base station, a first energy in a second portion of said reverse link frequency band, said second portion containing said first portion;

(c) means for measuring, at said base station, a second energy in said reverse link frequency band; and

(d) means for computing, at said base station, said reverse link loading utilizing said first energy and said second energy.

22. The apparatus in accordance with claim 21 wherein a position of said portion within said reverse link frequency band is invariable with time.

23. The apparatus in accordance with claim 21 wherein a position of said portion within said reverse link frequency band is variable with time.

24. The apparatus in accordance with claim 23 wherein said variation with time is continuous in time.

25. The apparatus in accordance with claim 23 wherein said variation with time is discontinuous in time.

26. The apparatus in accordance with claim 21 wherein the means for transmitting from a remote station a signal comprises:

(a) means for generating, at said remote station, said signal to be transmitted;

(b) means for filtering, at said remote station, said signal by a notch filter; and

(c) means for transmitting from said remote station said filtered signal.

27. The apparatus in accordance with claim 21 wherein the means for measuring, at a base station, a first energy comprise:

(a) means for filtering, at said base station, said reverse link frequency band by a band-pass filter; and

(b) means for measuring, at said base station, said first energy of said filtered reverse link frequency band.

28. The apparatus in accordance with claim 21 wherein the means for computing, said reverse link loading evaluate an equation:

$\mathrm{RLL}=\frac{I_o}{\left[I_{\mathrm{Notch}}-2<br><br>I_O<br><br>\left(\frac{B_{\mathrm{Bandpass}}-B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}\right)\right]}<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band;

(iv) B_Notch is said first portion of said reverse link frequency band; and

(v) B_Bandpass is said second portion of said reverse link frequency band.

29. The apparatus in accordance with claim 21 wherein the means for computing, said reverse link loading evaluate an equation:

$\mathrm{RLL}=\frac{I_O}{I_{\mathrm{Notch}}}·<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band; and

(iv) B_Notch is said first portion of said reverse link frequency band.

30. The apparatus in accordance with claim 21 wherein said wireless communication system is a spread spectrum wireless system.

31. The apparatus in accordance with claim 21 wherein said spread spectrum wireless communication system is a direct sequence spread spectrum wireless system.

32. The apparatus in accordance with claim 21 wherein said spread spectrum wireless communication system is a frequency hopped spread spectrum wireless system.

33. An apparatus for estimating a reverse link loading in a wireless communication system comprising:

(a) means for generating, at a remote station, a signal to be transmitted;

(b) means for filtering, at said remote station, said signal by a notch filter, wherein a position of said notch within said reverse link frequency band is invariable with time; and

(c) means for transmitting from said remote station said filtered signal.

34. An apparatus for estimating a reverse link loading in a wireless communication system comprising:

(d) means for generating, at a remote station, a signal to be transmitted;

(e) means for filtering, at said remote station, said signal by a notch filter, wherein a position of said notch within said reverse link frequency band is variable with time; and

(f) means for transmitting from said remote station said filtered signal.

35. The apparatus in accordance with claim 34 wherein said variation with time is continuous in time.

36. The apparatus in accordance with claim 34 wherein said variation with time is discontinuous in time.

37. A apparatus for estimating a reverse link loading by a base station comprising:

(a) means for receiving, at said base station, a reverse link signal containing negligible energy in at least a first portion of a reverse link frequency band;

(b) means for measuring, at said base station, a first energy in a second portion of said reverse link frequency band, said second portion containing said first portion;

(c) measuring, at said base station, a second energy in said reverse link frequency band; and

(d) computing, at said base station, said reverse link loading utilizing said first energy and said second energy.

38. The apparatus in accordance with claim 37 wherein the means for measuring a first energy comprises:

(a) means for filtering, at said base station, said reverse link frequency band by a band-pass filter; and

(b) means for measuring, at said base station, said first energy of said filtered reverse link frequency band.

39. The apparatus in accordance with claim 37 wherein the means for computing said reverse link loading proceeds in accordance with an equation:

$\mathrm{RLL}=\frac{I_o}{\left[I_{\mathrm{Notch}}-2<br><br>I_O<br><br>\left(\frac{B_{\mathrm{Bandpass}}-B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}\right)\right]}<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band;

(iv) B_Notch is said first portion of said reverse link frequency band; and

(v) B_Bandpass is said second portion of said reverse link frequency band.

40. The apparatus in accordance with claim 37 wherein the means for computing said reverse link loading proceeds in accordance with an equation:

$\mathrm{RLL}=\frac{I_o}{I_{\mathrm{Notch}}}·<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band; and

(iv) B_Notch is said first portion of said reverse link frequency band.

41. An apparatus for estimating a reverse link loading in a wireless communication system comprising:

(a) a remote station comprising;

(1) a signal source;

(2) a first filter, communicatively coupled to said signal source, said first filter passing negligible energy in at least a first portion of a frequency band; and

(3) a transmitter, communicatively coupled to said first filter, said transmitter transmitting said filtered signal; and

(b) a base station comprising;

(1) a receiver for receiving said signal from said remote station;

(2) a second filter, communicatively coupled to said receiver, said second filter passing energy in second portion of said frequency band, said second portion containing said first portion;

(3) a first processor, communicatively coupled to said second filter, said first processor being configured to evaluate a first energy of a signal filtered by said second filter;

(4) a second processor, communicatively coupled to said receiver, said second processor being configured to evaluate a second energy of said received signal; and

(5) a third processor, communicatively coupled to said first and said second processors, said third processor being configured to compute said reverse link loading using said first energy and said second energy.

42. The apparatus in accordance with claim 41 wherein a position of said portion within said reverse link frequency band is invariable with time.

43. The apparatus in accordance with claim 41 wherein a position of said portion within said reverse link frequency band is variable with time.

44. The apparatus in accordance with claim 43 wherein said variation with time is continuous in time.

45. The apparatus in accordance with claim 43 wherein said variation with time is discontinuous in time.

46. The apparatus in accordance with claim 41 wherein said third processor is configured to compute said reverse link loading by evaluating an equation:

$\mathrm{RLL}=\frac{I_o}{\left[I_{\mathrm{Notch}}-2<br><br>I_o<br><br>\left(\frac{B_{\mathrm{Bandpass}}-B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}\right)\right]}<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band;

(iv) B_Notch is said first portion of said reverse link frequency band; and

(v) B_Bandpass is said second portion of said reverse link frequency band.

47. The apparatus in accordance with claim 41 wherein said third processor is configured to compute said reverse link loading by evaluating an equation:

$\mathrm{RLL}=\frac{I_o}{I_{\mathrm{Notch}}}·<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band; and

(iv) B_Notch is said first portion of said reverse link frequency band.

48. The apparatus in accordance with claim 41 wherein said wireless communication system is a spread spectrum wireless system.

49. The apparatus in accordance with claim 41 wherein said spread spectrum wireless communication system is a direct sequence spread spectrum wireless system.

50. The apparatus in accordance with claim 41 wherein said spread spectrum wireless communication system is a frequency hopped spread spectrum wireless system.

51. An apparatus for estimating a reverse link loading in a wireless communication system comprising:

(a) a signal source;

(b) a first filter, communicatively coupled to said signal source, said filter passing negligible energy in at least a portion of a frequency band, wherein a position of said portion within said frequency band is invariable with time; and

(c) a transmitter, communicatively coupled to said first filter, said transmitter transmitting said filtered signal.

52. An apparatus for estimating a reverse link loading in a wireless communication system comprising:

(d) a signal source;

(e) a first filter, communicatively coupled to said signal source, said filter passing negligible energy in at least a portion of a frequency band, wherein a position of said portion within said frequency band is variable with time; and

(f) a transmitter, communicatively coupled to said first filter, said transmitted transmitting said filtered signal.

53. The apparatus in accordance with claim 52 wherein said variation with time is continuous in time.

54. The apparatus in accordance with claim 52 wherein said variation with time is discontinuous in time.

55. An apparatus for estimating a reverse link loading in a wireless communication system comprising:

(a) a receiver for receiving a signal from a remote station, said signal containing negligible energy in at least a first portion of said reverse link frequency band;

(b) a filter, communicatively coupled to said receiver, said filter passing energy in a second portion of received frequency band, said second portion containing said first portion;

(c) a first processor, communicatively coupled to said filter, said first processor being configured to evaluate a first energy of a signal filtered by said filter;

(d) a second processor, communicatively coupled to said receiver, said second processor being configured to evaluate a second energy of said received signal; and

(e) a third processor, communicatively coupled to said first and said second processors, said third processor being configured to compute said reverse link loading utilizing said first energy and said second energy.

56. The apparatus in accordance with claim 55 wherein said third processor is configured to compute said reverse link loading by evaluating an equation:

$\mathrm{RLL}=\frac{I_o}{\left[I_{\mathrm{Notch}}-2<br><br>I_o<br><br>\left(\frac{B_{\mathrm{Bandpass}}-B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}\right)\right]}<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band;

(iv) B_Notch is said first portion of said reverse link frequency band; and

in (v) B_Bandpass is said second portion of said reverse link frequency band.

57. The apparatus in accordance with claim 55 wherein said third processor is configured to compute said reverse link loading by evaluating an equation:

$\mathrm{RLL}=\frac{I_o}{I_{\mathrm{Notch}}}·<br><br>\frac{2<br><br>B_{\mathrm{Notch}}}{B_{\mathrm{Total}}}$

wherein;

(i) I_O is said second energy;

(ii) I_Notch is said first energy;

(iii) B_Total is said reverse link frequency band; and

(iv) B_Notch is said first portion of said reverse link frequency band.