Method and apparatus for utilizing channel state information in a wireless communication system

• US 7,949,060 B2
• Filed: 09/04/2009
• Issued: 05/24/2011
• Est. Priority Date: 03/23/2001
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wallace, Mark, Walton, Jay R., Howard, Steven J., Ketchum, John W., Ling, Fuyun
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US12/554,608
• Publication Number:
  US 20090323851A1
• Time in Patent Office: 627 Days
• Field of Search: 375/267, 375/260, 375/296, 375/347, 375/349, 375/299, 375/348, 375/144, 375/148, 375/285, 375/220, 375/261, 455/101, 455/452.1, 455/452.2, 370/334, 370/332
• US Class Current: 375/260
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04B 7/0891 Space-time diversity rake receivers H04B1/7115; space-time decoding H04L1/0631
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0015 characterised by the adaptation strategy
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• 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 2025/03802 Signalling on the reverse channel
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/021 Estimation of channel covariance
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 25/0244 with inversion
• CPC Class Codes: H04L 25/0248 Eigen-space methods
• CPC Class Codes: H04L 25/03159 operating in the frequency domain H04L25/03165, H04L25/03178 take precedence
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0044 : allocation of payload
• CPC Class Codes: H04L 5/006 : Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0091 : Signaling for the administration of the divided path

Abstract

Techniques for transmitting data from a transmitter unit to a receiver unit in a multiple-input multiple-output (MIMO) communication system. In one method, at the receiver unit, a number of signals are received via a number of receive antennas, with the received signal from each receive antenna comprising a combination of one or more signals transmitted from the transmitter unit. The received signals are processed to derive channel state information (CSI) indicative of characteristics of a number of transmission channels used for data transmission. The CSI is transmitted back to the transmitter unit. At the transmitter unit, the CSI from the receiver unit is received and data for transmission to the receiver unit is processed based on the received CSI.

Claims

1. A method for reporting channel state information (CSI) in a multiple-input multiple-output (MIMO) communication system, comprising:

receiving a plurality of signals via a plurality of receive antennas, wherein the received signal from each receive antenna comprises a combination of one or more signals transmitted from the transmitter unit;

processing the received signals to derive channel state information (CSI) indicative of characteristics of a plurality of transmission channels used for data transmission;

transmitting the CSI back to the transmitter unit; and

transmitting differential updates to the CSI back to the transmitter unit.

2. The method of claim 1, wherein the differential updates represent a change relative to previously transmitted CSI.

3. The method of claim 1, wherein the CSI comprises:

sufficient information for the transmitter unit to calculate eigenvalues and eigenmodes for each frequency subchannel utilized in downlink transmissions.

4. The method of claim 1, wherein the CSI comprises information indicative of eigenmodes and eigenvalues for the plurality of transmission channels.

5. The method of claim 4, wherein differential updates represent corrections to the eigenmodes.

6. The method of claim 1, wherein differential updates are transmitted only when changes in CSI exceed a threshold amount.

7. The method of claim 6, wherein:

the CSI comprises signal to noise ratios (SNRs) for a plurality of frequency subchannels; and

differential updates are transmitted only when a change in the SNR for one or more of the frequency subchannels exceeds a threshold amount.

8. A method for processing channel state information (CSI) in a multiple-input multiple-output (MIMO) communication system, comprising:

transmitting signals to receiver unit via a plurality of transmit antennas on a plurality of transmission channels;

receiving, from the receiver unit, channel state information (CSI) derived by the receiver unit based on the transmitted signals, the CSI indicative of characteristics of the plurality of transmission channels used for data transmission;

receiving differential updates to the CSI from the receiver unit;

applying the differential updates to the CSI to obtain updated CSI; and

processing data for transmission to the receiver unit in accordance with the updated CSI.

9. The method of claim 8, wherein the differential updates represent a change relative to previously transmitted CSI.

10. The method of claim 8, wherein the CSI comprises:

sufficient information to calculate eigenvalues and eigenmodes for each frequency subchannel utilized in downlink transmissions to the receiver unit.

11. The method of claim 8, wherein the CSI comprises information indicative of eigenmodes and eigenvalues for the plurality of transmission channels.

12. The method of claim 11, wherein the differential updates represent corrections to the eigenmodes.

13. The method of claim 8, wherein the receiver unit transmits differential updates only when changes in CSI exceed a threshold amount.

14. The method of claim 13, wherein:

the CSI comprises signal to noise ratios (SNRs) for a plurality of frequency subchannels; and

differential updates are transmitted by the receiver unit only when a change in the SNR for one or more of the frequency subchannels exceeds a threshold amount.

15. An apparatus for reporting channel state information (CSI) in a multiple-input multiple-output (MIMO) communication system, comprising:

means for receiving a plurality of signals via a plurality of receive antennas, wherein the received signal from each receive antenna comprises a combination of one or more signals transmitted from a transmitter unit;

means for processing the received signals to derive channel state information (CSI) indicative of characteristics of a plurality of transmission channels used for data transmission;

means for transmitting the CSI back to the transmitter unit; and

transmitting differential updates to the CSI back to the transmitter unit.

16. An apparatus for processing channel state information (CSI) in a multiple-input multiple output (MIMO) communication system, comprising:

means for transmitting signals to receiver unit via a plurality of transmit antennas on a plurality of transmission channels;

means for receiving, from the receiver unit, channel state information (CSI) derived by the receiver unit based on the transmitted signals, the CSI indicative of characteristics of the plurality of transmission channels used for data transmission;

means for receiving differential updates to the CSI from the receiver unit;

means for applying the differential updates to the CSI to obtain updated CSI; and

means for processing data for transmission to the receiver unit in accordance with the updated CSI.

17. An apparatus for reporting channel state information (CSI) in a multiple-input multiple-output (MIMO) communication system, comprising:

at least one processor configured to execute program codes for;

receiving a plurality of signals via a plurality of receive antennas, wherein the received signal from each receive antenna comprises a combination of one or more signals transmitted from a transmitter unit,

processing the received signals to derive channel state information (CSI) indicative of characteristics of a plurality of transmission channels used for data transmission,

transmitting the CSI back to the transmitter unit, and

transmitting differential updates to the CSI back to the transmitter unit.

18. An apparatus for processing channel state information (CSI) in a multiple-input multiple output (MIMO) communication system, comprising:

at least one processor configured to execute program codes for;

transmitting signals to receiver unit via a plurality of transmit antennas on a plurality of transmission channels;

receiving, from the receiver unit, channel state information (CSI) derived by the receiver unit based on the transmitted signals, the CSI indicative of characteristics of the plurality of transmission channels used for data transmission;

receiving differential updates to the CSI from the receiver unit;

applying the differential updates to the CSI to obtain updated CSI; and

processing data for transmission to the receiver unit in accordance with the updated CSI.