Method for estimating wireless channel parameters

• US 20060045194A1
• Filed: 08/29/2005
• Published: 03/02/2006
• Est. Priority Date: 08/31/2004
• Status: Active Grant

• Current Assignee: Theta IP, LLC
• Original Assignee: Theta Microelectronics, Inc.
• Inventors: Grigorios, Kalivas, Athanasios, Doukas
• Granted Patent: US 7,702,045 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• 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;

determining if a detailed estimation of the channel'"'"'s parameters is necessary, and if so, performing at least one of a), b) and c);

a) an exact channel estimation by parametric analysis;

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

c) a simplified channel estimation;

determining if it is necessary to alter the transmission characteristics and if so, altering the transmission characteristics.

2. The method of claim 1 wherein the method is repeated for each of the transmission channels in a multi-channel wireless communication system.

3. 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.

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

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 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.

7. 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.

8. 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.

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

a channel estimator configured to;

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

determine if a detailed estimation is necessary and if so, perform at least one of;

a) an exact channel estimation by parametric analysis;

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

c) a simplified channel estimation;

then determine if it is necessary to alter the transmission characteristics and if so, alter the transmission characteristics.

10. The wireless system of claim 9 wherein the channel estimator is enabled to repeat channel estimation for each of the transmission channels.

11. The wireless system of claim 9 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.

12. The wireless system of claim 11 wherein the coarse estimation is done by parametric analysis.

13. The wireless system of claim 9 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.

14. The wireless system of claim 9 wherein the wireless system is a receiver.

15. The wireless system of claim 9 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.

16. The wireless system of claim 9 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.

17. The wireless system of claim 9 wherein if the detailed estimation is the first to be performed then an exact channel estimation by parametric analysis is used.

18. A wireless receiver equipped with the channel estimator of claim 9.