Method and system for multiple channel wireless transmitter and receiver phase and amplitude calibration

• US 20050117677A1
• Filed: 12/30/2004
• Published: 06/02/2005
• Est. Priority Date: 05/29/2002
• Status: Abandoned Application

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Intel Corporation
• Inventors: Sampath, Hemanth
• Application Number:
  US11/026,949
• Publication Number:
  US 20050117677A1
• Time in Patent Office: Days
• US Class Current: 375/347
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 1/242 by comparing a transmitted test signal with a locally generated replica
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0214 of a single coefficient
• 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 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

The present invention provides a method and system for estimating common amplitude and phase errors of a multiple channel wireless system. The multiple channel wireless system includes a plurality of transmission channels formed between a plurality of transmission antennas and a plurality of receiver antennas. The method includes estimating transmission channel elements between each transmission antenna and receiver antenna pair of the multiple channel wireless system. Calibration symbols are transmitted from each transmit antenna. Signals are received that correspond to the calibration symbols having traveled through the transmission channels. Received calibration symbols are estimated based upon spatial processing of the received signals and the estimated transmission channel elements. Common amplitude and phase errors are estimated for each transmit and receive antenna pair by comparing the transmitted calibration symbols with the received calibration symbols.

Claims

1. A method of estimating common amplitude and phase errors of a multiple channel wireless system, the multiple channel wireless system comprising a plurality of transmission channels formed between a plurality of transmission antennas and a plurality of receiver antennas, the method comprising:

estimating transmission channel elements between each transmission antenna and receiver antenna pair of the multiple channel wireless system;

transmitting calibration symbols from each transmit antenna;

receiving signals corresponding to the calibration symbols having traveled through the transmission channels;

estimating received calibration symbols based upon spatial processing of the received signals and the estimated transmission channel elements; and

estimating common amplitude and phase errors for each transmit and receive antenna pair by comparing the transmitted calibration symbols with the received calibration symbols.

2. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 1, further comprising:

correcting spatially processed received data symbols with the estimated common amplitude and phase errors.

3. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 1, further comprising:

correcting the estimated transmission channel elements with the estimated common amplitude and phase errors.

4. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 1, wherein transmission chains associated with the transmission antennas are independent, and receiver chains associated with the receiver antennas are dependent, the method further comprising:

forming a channel matrix from the transmission channel elements between each transmit antenna and receive antenna pair; and

wherein the spatial processing comprises;

estimating the received calibration symbols using the channel matrix and an equivalent maximum likelihood (ML) receiver structure.

5. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 1, wherein transmission chains associated with the transmission antennas are independent, and receiver chains associated with the receiver antennas are dependent, the method further comprising:

forming a channel matrix from the transmission multiplier estimates between each transmit antenna and receive antenna pair; and

wherein the spatial processing comprises;

estimating the received calibration symbols using the channel matrix and an equivalent minimum mean squared error (MMSE) receiver structure.

6. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 1, wherein transmission chains associated with the transmission antennas are independent, and receiver chains associated with the receiver antennas are dependent, the method further comprising:

forming a channel matrix from the transmission multiplier estimates between each transmit antenna and receive antenna pair; and

wherein the spatial processing comprises;

estimating the received calibration symbols using the channel matrix and an equivalent zero forcing (ZF) receiver structure.

7. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 1, wherein transmission chains associated with the transmission antennas are independent, and receiver chains associated with the receiver antennas are dependent, the method further comprising:

forming a channel matrix from the transmission multiplier estimates between each transmit antenna and receive antenna pair; and

wherein the spatial processing comprises;

estimating the received calibration symbols using the channel matrix and an equivalent decision feedback equalizer (DFE) receiver structure.

8. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 1, wherein transmission chains associated with the transmission antennas are dependent, and receiver chains associated with the receiver antennas are independent,

and wherein identical transmission calibration symbols are transmitted from all of the transmission antennas;

the method further comprising;

generating a summed channel scalar for each receiver antenna by summing transmission channel elements corresponding with the receiver antenna; and

wherein the spatial processing comprises;

estimating the received calibration symbol for each receiver antenna using the corresponding summed channel scalar and an equivalent maximum likelihood (ML) receiver structure.

9. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 1, wherein transmission chains associated with the transmission antennas are dependent, and receiver chains associated with the receiver antennas are independent,

and wherein identical transmission calibration symbols are transmitted from all of the transmission antennas;

the method further comprising;

generating a summed channel scalar for each receiver antenna by summing transmission channel elements corresponding with the receiver antenna; and

wherein the spatial processing comprises;

estimating the received calibration symbol for each receiver antenna using the corresponding summed channel scalar and a zero forcing (ZF) receiver structure.

10. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 1, wherein transmission chains associated with the transmission antennas are independent, and receiver chains associated with the receiver antennas are independent, and

wherein transmitting calibration symbols from each transmit antenna comprises progressively transmitting calibration symbols from each transmission antenna while all other transmission antennas are zeroed;

and

further comprising;

forming an inverted channel element by inverting the transmission channel elements for each transmit antenna and receive antenna pair; and

estimating the received calibration symbol for each receiver antenna based upon spatial processing of the received signals of the corresponding receiver antenna and the corresponding inverted channel element.

11. A method of estimating common amplitude and phase errors of a multiple channel wireless system, the multiple channel wireless system comprising a plurality of transmission channels formed between at least one transmission antenna and at least one receiver antenna, the method comprising:

estimating transmission channel elements between each transmission antenna and receiver antenna pair of the multiple channel wireless system for a plurality of carriers of a multiple carrier transmission signal;

transmitting calibration symbols from each transmit antenna for the plurality of carriers of the multiple carrier transmission signal;

receiving signals corresponding to the calibration symbols having traveled through the transmission channels;

estimating received calibration symbols based upon spatial processing of the received signals and the estimated transmission channel elements; and

estimating common amplitude and phase errors for each transmit and receive antenna pair by comparing the transmitted calibration symbols with the received calibration symbols.

12. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 11, wherein the spatial processing comprises:

estimating received calibration symbols using the estimated transmission channel elements and an equivalent of at least one of an ML, MMSE, ZF and DFE receiver structures.

13. A method of estimating common amplitude and phase errors of a multiple channel wireless system, the multiple channel wireless system comprising a plurality of transmission channels formed between at least one transmission antenna and at least one receiver antenna, the method comprising:

estimating transmission channel elements between each transmission antenna and receiver antenna pair of the multiple channel wireless system for a plurality of transmission time slots;

transmitting calibration symbols from each transmit antenna for the plurality of transmission time slots;

receiving signals corresponding to the calibration symbols having traveled through the transmission channels;

estimating received calibration symbols based upon spatial processing of the received signals and the estimated transmission channel elements; and

estimating common amplitude and phase errors for each transmit and receive antenna pair by comparing the transmitted calibration symbols of the with the received calibration symbols.

14. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 13, wherein the spatial processing comprises:

estimating received calibration symbols using the estimated transmission channel elements and an equivalent of at least one of an ML, MMSE, ZF and DFE receiver structures.

15. A method of estimating common amplitude and phase errors of a multiple channel wireless system, the multiple channel wireless system comprising a plurality of transmission channels formed between at least one transmission antenna and at least one receiver antenna, the method comprising:

estimating transmission channel elements between each transmission antenna and receiver antenna pair of the multiple channel wireless system for a plurality of carriers of a multiple carrier transmission signal and a plurality of time slots;

transmitting calibration symbols from each transmit antenna for the plurality of carriers of the multiple carrier transmission signal and plurality of time slots;

receiving signals corresponding to the calibration symbols having traveled through transmission channels;

estimating received calibration symbols based upon spatial processing of the received signals and the estimated transmission channel elements; and

estimating common amplitude and phase errors for each transmit and receive antenna pair by comparing the transmitted calibration symbols of the with the received calibration symbols.

16. The method of estimating common amplitude and phase errors of a multiple channel wireless system of claim 15, wherein the spatial processing comprises:

estimating received calibration symbols using the estimated transmission channel elements and an equivalent of at least one of an ML, MMSE, ZF and DFE receiver structures.

17. An apparatus for estimating common amplitude and phase errors of a multiple channel wireless system, the multiple channel wireless system comprising a plurality of transmission channels formed between a plurality of transmission antennas and a plurality of receiver antennas, the apparatus comprising:

means for estimating transmission channel elements between each transmission antenna and receiver antenna pair of the multiple channel wireless system;

means for transmitting calibration symbols from each transmit antenna;

means for receiving signals corresponding to the calibration symbols having traveled through the transmission channels;

means for estimating received calibration symbols based upon spatial processing of the received signals and the estimated transmission channel elements; and

means for estimating common amplitude and phase errors for each transmit and receive antenna pair by comparing the transmitted calibration symbols with the received calibration symbols.

18. An apparatus for estimating common amplitude and phase errors of a multiple channel wireless system, the multiple channel wireless system comprising a plurality of transmission channels formed between at least one transmission antenna and at least one receiver antenna, the apparatus comprising:

means for estimating transmission channel elements between each transmission antenna and receiver antenna pair of the multiple channel wireless system for a plurality of carriers of a multiple carrier transmission signal;

means for transmitting calibration symbols from each transmit antenna for the plurality of carriers of the multiple carrier transmission signal;

means for receiving signals corresponding to the calibration symbols having traveled through the transmission channels;

means for estimating received calibration symbols based upon spatial processing of the received signals and the estimated transmission channel elements; and

means for estimating common amplitude and phase errors for each transmit and receive antenna pair by comparing the transmitted calibration symbols with the received calibration symbols.

19. An apparatus for estimating common amplitude and phase errors of a multiple channel wireless system, the multiple channel wireless system comprising a plurality of transmission channels formed between at least one transmission antenna and at least one receiver antenna, the apparatus comprising:

means for estimating transmission channel elements between each transmission antenna and receiver antenna pair of the multiple channel wireless system for a plurality of transmission time slots;

means for transmitting calibration symbols from each transmit antenna for the plurality of transmission time slots;

means for receiving signals corresponding to the calibration symbols having traveled through the transmission channels;

means for estimating received calibration symbols based upon spatial processing of the received signals and the estimated transmission channel elements; and

means for estimating common amplitude and phase errors for each transmit and receive antenna pair by comparing the transmitted calibration symbols of the with the received calibration symbols.

20. An apparatus for estimating common amplitude and phase errors of a multiple channel wireless system, the multiple channel wireless system comprising a plurality of transmission channels formed between at least one transmission antenna and at least one receiver antenna, the apparatus comprising:

means for estimating transmission channel elements between each transmission antenna and receiver antenna pair of the multiple channel wireless system for a plurality of carriers of a multiple carrier transmission signal and a plurality of time slots;

means for transmitting calibration symbols from each transmit antenna for the plurality of carriers of the multiple carrier transmission signal and plurality of time slots;

means for receiving signals corresponding to the calibration symbols having traveled through the transmission channels;

means for estimating received calibration symbols based upon spatial processing of the received signals and the estimated transmission channel elements; and

means for estimating common amplitude and phase errors for each transmit and receive antenna pair by comparing the transmitted calibration symbols of the with the received calibration symbols.