Method for estimating wireless channel parameters

• US 7,702,045 B2
• Filed: 08/29/2005
• Issued: 04/20/2010
• Est. Priority Date: 08/31/2004
• Status: Active Grant

• Current Assignee: Theta IP, LLC
• Original Assignee: Theta Microelectronics, Inc.
• Inventors: Athanasios, Doukas, Grigorios, Kalivas
• Primary Examiner(s): Tran, Khanh C
• Application Number:
  US11/214,217
• Publication Number:
  US 20060045194A1
• Time in Patent Office: 1,695 Days
• Field of Search: 375/260, 375340-343, 375/346, 370/208, 370/210
• US Class Current: 375/342
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters

Abstract

Method for the estimation of channel parameters in a wireless communication system. In accordance with the method several levels of the wireless channel parameters estimation take place to address the specific requirements of the channel. Based on the level of estimation required an appropriate estimation algorithm is selected to achieve the desired results. The evaluation of the channel state and thereafter determining the appropriate parameter estimation requirements provide for a superior overall performance of the wireless system.

Claims

1. A method of estimation of channel parameters dependent on the channel conditions in a wireless communication system comprising:

performing a coarse estimation of a channel'"'"'s parameters by channel estimator apparatus of the wireless communication system;

determining if a detailed estimation of the channel'"'"'s parameters is necessary responsive to performing the coarse estimation, and if so, performing, by the channel estimator apparatus, at least one of a plurality of estimations selected from;

a) an exact channel estimation by parametric analysis;

b) an exact channel estimation by applying a discrete Fourier transform analysis;

c) an exact channel estimation by a simplified channel estimation;

determining if it is necessary to alter the transmission characteristics responsive of the coarse estimation and/or the detailed estimation of the channel'"'"'s parameters and if so, altering the transmission characteristics of the wireless communication system;

wherein the method is repeated for each of the transmission channels in a multi-channel wireless communication system.

2. The method of claim 1 wherein the coarse estimation is performed based on at least one of:

a) signal-to-noise ratio of the channel,

b) channel frequency selectivity,

c) Ricean K factor, and

d) Doppler frequency.

3. The method of claim 2 wherein the coarse estimation is performed by parametric analysis.

4. The method of claim 2, wherein at least one more coarse estimation is performed based on a not previously utilized estimation method.

5. The method of claim 1 wherein the parametric analysis of the exact channel estimation is performed based on at least, one of:

a) signal-to-noise ratio of the channel,

b) channel frequency selectivity,

c) Ricean K factor, and

d) Doppler frequency.

6. The method of claim 5, wherein at least one more coarse estimation is performed based on a not previously utilized estimation method for that channel.

7. The method of claim 1 wherein the exact channel estimation is performed by applying a discrete Fourier transform if the coarse channel estimation parameters from a previous estimation are sufficiently different from a current estimation and if in the previous run exact channel estimation was performed.

8. The method of claim 1 wherein the exact channel estimation is performed by simplified channel estimation if the coarse channel estimation parameters from a previous estimation are sufficiently different from a current estimation and if it is determined that a simplified channel estimation is needed.

9. The method of claim 1, wherein if the detailed estimation is the first estimation to be performed, then an exact channel estimation by parametric analysis is performed.

10. The method of claim 1 wherein performing a coarse estimation of a channel'"'"'s parameters by a channel estimator apparatus of the wireless communication system comprises performing a coarse estimation of a plurality of the channel'"'"'s parameters by the channel estimator apparatus of the wireless communication system.

11. A multi-channel wireless system having a channel state evaluation operative in a multi-path environment, the system comprising:

a coarse channel estimator configured to perform a coarse estimation of the channel'"'"'s parameters;

a detailed channel estimator configured to determine if a detailed channel estimation is necessary responsive to the coarse estimation, and if so, performing at least one of a plurality of estimations selected from;

a) an exact channel estimation by parametric analysis;

b) an exact channel estimation by a discrete Fourier transform analysis;

c) an exact channel estimation by a simplified channel estimation;

then determine if it is necessary to alter the transmission characteristics responsive of the coarse estimation and/or the detailed estimation of the channel'"'"'s parameters and if so, alter the transmission characteristics of the wireless communication system;

wherein a channel estimator comprising said coarse channel estimator and said detailed channel estimator is enabled to repeat channel estimation for each of the transmission channels.

12. The wireless system of claim 11 wherein the channel estimator is enabled to perform the coarse estimation based on at least one of:

a) signal-to-noise ratio of the channel,

b) channel frequency selectivity,

c) Ricean K factor, and

d) Doppler frequency.

13. The wireless system of claim 12 wherein the coarse estimation is done by parametric analysis.

14. The method of claim 12, wherein at least one more coarse estimation is performed based on a not previously utilized estimation method for that channel.

15. The wireless system of claim 11 wherein the parametric analysis of the channel estimator for the exact channel estimation is performed based on at least one of:

a) signal-to-noise ratio of the channel,

b) channel frequency selectivity,

c) Ricean K factor, and

d) Doppler frequency.

16. The method of claim 15, wherein at least one more coarse estimation is performed based on a not previously utilized estimation method for that channel.

17. The wireless system of claim 11 wherein the wireless system is a receiver.

18. The wireless system of claim 11 wherein the exact channel estimation by applying a discrete Fourier transform is performed if the coarse channel estimation parameters from a previous run are sufficiently different from a current run and if in the previous run exact channel estimation was performed.

19. The wireless system of claim 11 wherein the exact channel estimation by simplified channel estimation is performed if the coarse channel estimation parameters from a previous run are sufficiently different from a current run and if it is determined that a simplified channel estimation is needed.

20. The wireless system of claim 11 wherein if the detailed estimation is the first to be performed then an exact channel estimation by parametric analysis is used.

21. A wireless receiver equipped with the channel estimator of claim 11.

22. The method of claim 11 wherein performing a coarse estimation of a channel'"'"'s parameters by a channel estimator apparatus of the wireless communication system comprises performing a coarse estimation of a plurality of the channel'"'"'s parameters by the channel estimator apparatus of the wireless communication system.