MIMO phase noise estimation and correction

• US 20080101497A1
• Filed: 10/30/2006
• Published: 05/01/2008
• Est. Priority Date: 10/30/2006
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Moorti, Rajendra T., Gaikwad, Rohit V.
• Application Number:
  US11/590,707
• Publication Number:
  US 20080101497A1
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04L 1/0631 Receiver arrangements
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 25/0242 using matrix methods
• CPC Class Codes: H04L 25/03159 operating in the frequency domain H04L25/03165, H04L25/03178 take precedence
• CPC Class Codes: H04L 25/03273 with carrier recovery circuitry
• CPC Class Codes: H04L 25/03292 with channel estimation circuitry
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

A technique to estimate phase noise across a multiple-input-multiple-output (MIMO) communication channel, in which phase noise estimation is obtained by solving a matrix equation that has more unknowns than available equations. Once the phase noise estimate is determined, appropriate phase correction is applied to correct for phase noise induced errors in the received signal.

Claims

1. A method comprising:

estimating a phase error for a signal communicated across a multiple antenna communication channel, in which each transmitting antenna and each receiving antenna has a phase noise component for a channel matrix used to calculate phase noise present in the signal; and

correcting for the phase error by applying phase correction to the signal based on the estimated phase error.

2. The method of claim 1, wherein the estimating includes collapsing the phase noise component of each transmitting antenna and the phase noise component of each receiving antenna into a single channel matrix and deriving combined phase noise components in the channel matrix.

3. The method of claim 2, wherein the estimating includes obtaining a respective mean value for each of the combined phase noise components for a segmented portions of the signal and using the respective mean values as common phase error values for the segmented portion.

4. The method of claim 2, wherein the estimating includes obtaining a respective mean value for each of the combined phase noise components for a symbol of the signal in which the mean value has a noise mean of zero for the symbol.

5. The method of claim 3, wherein the estimating includes using information conveyed in one or more tones present in the signal to solve channel matrix equations that have more unknowns than equations when calculating the channel matrix to solve for the combined phase noise components.

6. The method of claim 3, wherein the estimating includes using information conveyed in pilot tones present in the signal to solve channel matrix equations that have more unknowns than equations when calculating the channel matrix to solve for the combined phase noise components.

7. The method of claim 2, wherein the phase noise components of the transmitting antennas or the phase noise components of the receiving antennas are substantially the same, so that a number of phase noise components as unknowns when solving channel matrix equations is reduced.

8. A method comprising:

receiving a symbol associated with a signal transmitted across a communication channel of a multiple-input-multiple-output (MIMO) communication system;

estimating a phase error for the signal, in which each transmitting antenna and each receiving antenna of the MIMO system has a phase noise component for a channel matrix used to calculate phase noise present in the signal; and

correcting for the phase error by applying phase correction to the signal based on the estimated phase error.

9. The method of claim 8, wherein the estimating includes collapsing the phase noise component of each transmitting antenna and the phase noise component of each receiving antenna into a single channel matrix and deriving combined phase noise components in the channel matrix.

10. The method of claim 9, wherein the estimating includes obtaining a respective mean value for each of the combined phase noise components for the symbol in which the mean value has a noise mean of zero for the symbol.

11. The method of claim 9, wherein the estimating includes using information conveyed in one or more tones present in the signal to solve channel matrix equations that have more unknowns than equations when calculating the channel matrix to solve for the combined phase noise components.

12. The method of claim 9, wherein the estimating includes using information conveyed in pilot tones present in the signal to solve channel matrix equations that have more unknowns than equations when calculating the channel matrix to solve for the combined phase noise components.

13. The method of claim 9, wherein the phase noise components of the transmitting antennas or the phase noise components of the receiving antennas are substantially the same, so that a number of phase noise components as unknowns when solving channel matrix equations is reduced.

14. An apparatus comprising:

a sampling module coupled to receive an incoming signal communicated across a multiple-input-multiple-output (MIMO) communication channel and to sample the incoming signal;

a Fast Fourier Transform (FFT) module coupled to transform the sampled signal from a time-domain signal to a frequency-domain signal;

a phase noise estimating module coupled to the FFT module to estimate a phase error for the transformed frequency-domain signal, in which each transmitting antenna and each receiving antenna has a phase noise component for a channel matrix used to calculate phase noise present in the transformed signal; and

phase correcting module coupled to receive a phase correction signal from the phase estimating module to correct for the phase error.

15. The apparatus of claim 14, wherein the phase noise estimating module collapses the phase noise component of each transmitting antenna and the phase noise component of each receiving antenna into a single channel matrix to derive combined phase noise components in the channel matrix.

16. The apparatus of claim 15, wherein the phase noise estimating module finds a respective mean value for each of the combined phase noise components for a symbol of the signal in which the mean value has a noise mean of zero for the symbol.

17. The apparatus of claim 15, wherein the phase noise estimating module uses information conveyed in pilot tones present in the signal to solve channel matrix equations that have more unknowns than equations when calculating the channel matrix to solve for the combined phase noise components.

18. The apparatus of claim 15, wherein the phase noise components of the transmitting antennas or the phase noise components of the receiving antennas are substantially the same, so that a number of phase noise components as unknowns when solving channel matrix equations is reduced.