Adaptation Techniques in MIMO

• US 20090202014A1
• Filed: 08/05/2008
• Published: 08/13/2009
• Est. Priority Date: 02/11/2008
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Mobile Communications GmbH (Intel Corporation)
• Inventors: Mujtaba, Syed Aon, Wang, Xiaowen
• Granted Patent: US 8,855,257 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/068 using space frequency diversity space-frequency coding H04L1/0606
• CPC Class Codes: H04B 7/0888 with selection
• 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 1/0017 where the mode-switching is based on Quality of Service requirement
• CPC Class Codes: H04L 1/0054 Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/0625 Transmitter arrangements

Abstract

A method of the multiple input multiple output feedback is disclosed. In accordance with an embodiment of the invention, the multiple input multiple output feedback method includes a receiver receiving a reference signal from a base station and calculating a signal to interference and noise ratio from the received reference signal. The method further includes determining a modulation and coding scheme based on the signal to interference and noise ratio and a receiver type.

Claims

1. A feedback method comprising:

receiving a reference signal from multiple antennas on a base station;

calculating a signal to interference and noise ratio from the reference signal; and

determining a modulation and coding scheme based on the signal to interference and noise ratio and a receiver type.

2. The method of claim 1, further comprising calculating a rank and precoding matrix based on estimated channel information from the received reference signal, wherein calculating the signal to interference and noise ratio comprises calculating a signal to interference and noise ratio for each of a plurality of layers based on the preceding matrix and the estimated channel information.

3. The method of claim 2, wherein determining a modulation and coding scheme comprises selecting the modulation and coding scheme according to the calculated signal to interference and noise ratio and the receiver type, wherein the selecting comprises selecting from a lookup table.

4. The method of claim 1, wherein calculating a signal to interference and noise ratio comprises calculating an average signal to interference and noise ratio based on estimated channel information from the received reference signal.

5. The method of claim 4, wherein determining a modulation and coding scheme comprises:

calculating a modulation and coding scheme for each of a plurality of transmission schemes and for each of a plurality of ranks based on the average signal to interference and noise ratio; and

selecting a rank and selecting a modulation and coding scheme, wherein the selecting is based on a rank and modulation and coding scheme that maximizes throughput.

6. The method of claim 1, further comprising:

estimating channel information from the reference signals, the signal to interference and noise ratio being calculated based on the estimated channel information; and

sending feedback information to the base station, the feedback information comprising the rank and modulation and coding scheme.

7. The method of claim 6, wherein the feedback information comprises information to generate a precoding matrix.

8. The method of claim 1, wherein the receiving occurs in a receiver that is moving at high vehicular speeds relative to the base station.

9. The method of claim 8, wherein the receiver is moving at a velocity greater than 30 km/hr.

10. An open loop MIMO feedback procedure comprising:

estimating channel state information by receiving at least one reference signal from transmitter antennas on a base station;

calculating an average signal to interference and noise ratio from the estimated channel information at an user end receiver;

using the average signal to interference and noise ratio (SINR) and the user end receiver type to calculate a modulation and channel scheme for each available rank;

calculating a throughput rate for each rank and the corresponding modulation and coding scheme associated for that rank;

selecting a rank and modulation and coding scheme to maximize the throughput rate; and

sending a feedback information from the user end receiver to the base station, the feedback information comprising the selected rank and modulation and coding scheme.

11. The open loop MIMO feedback procedure of claim 10, wherein the user end receiver type comprises a linear receiver;

12. The open loop MIMO feedback procedure of claim 10, wherein the user end receiver type comprises a Maximum Likelihood receiver or a Minimum Mean Square Error receiver.

13. The open loop MIMO feedback procedure of claim 10, wherein the base station uses the feedback information in transmitting a subsequent information, wherein the base station does not change the selected rank and modulation and coding scheme, wherein the feedback procedure is performed dynamically during a link between the base station and the user end, and wherein the feedback information is dynamically adjusted during the link.

14. The open loop MIMO feedback procedure of claim 10, wherein using the average signal to interference and noise ratio and the user end receiver type to calculate a modulation and channel scheme for each available rank comprises using a predetermined lookup table, wherein the look up table comprises a mapping of receiver type, SINR, and modulation and coding schemes.

15. The open loop MIMO feedback procedure of claim 10, wherein the user end receiver is moving at medium or high vehicular speeds.

16. A closed loop MIMO feedback procedure comprising:

receiving at least one reference signal from a base station;

calculating a rank and a precoding matrix from the received reference signal;

calculating a signal to interference and noise ratio (SINR) for each layer from the precoding matrix;

selecting a modulation and coding scheme based on the signal to interference and noise ratio and a receiver type; and

sending a feedback information to the base station, the feedback information comprising the determined modulation and coding scheme.

17. The closed loop MIMO feedback procedure of claim 16, wherein the receiver type comprises a Maximum Likelihood receiver or a Minimum Mean Square Error receiver.

18. The closed loop MIMO feedback procedure of claim 16, wherein the base station uses the feedback information in transmitting a subsequent signal, wherein the base station does not change the rank or modulation and coding scheme selected by the user end receiver, and wherein the feedback information further comprises a precoding matrix index.

19. The closed loop MIMO feedback procedure of claim 16, wherein the feedback procedure is performed dynamically during a link between the base station and the user end, and wherein the feedback information is dynamically adjusted during the link.

20. The closed loop MIMO feedback procedure of claim 16, wherein determining a modulation and coding scheme comprises using a predetermined lookup table comprising a mapping of receiver type, SINR, and modulation and coding schemes.

21. The closed loop MIMO feedback procedure of claim 16, wherein the user end receiver is moving at medium or high vehicular speeds.

22. A receiver comprising:

a plurality of antennas for receiving signals from a base station, the plurality of antennas configured to receive reference signals transmitted from antennas on a base station and to transmit a feedback information to the base station; and

a processor configured to receive the reference signal from the plurality of antennas, the processor configured to calculate a signal to interference and noise ratio from the reference signal and to determine a modulation and coding scheme based on the signal to interference and noise ratio and a receiver type, wherein the processor is configured to submit the feedback information comprising the modulation and coding scheme to the plurality of antennas.

23. The receiver of claim 22, wherein the processor calculates a modulation and channel scheme for each available rank using the average signal to interference and noise ratio (SINR) and the receiver type and a throughput rate for each rank and the corresponding modulation and coding scheme associated for that rank, and wherein the processor selects a rank and modulation and coding scheme to maximize the throughput rate.

24. The receiver of claim 22, wherein the processor

calculates a rank and a precoding matrix from the received reference signal, and the signal to interference and noise ratio (SINR) for each layer from the precoding matrix;

and

wherein the processor selects a modulation and coding scheme based on the signal to interference and noise ratio and the receiver type.

25. A user unit comprising:

antennas for transmitting and receiving signals to and from a base station;

at least one processor for running software, the software comprising code for calculating a signal to interference and noise ratio from a reference signal received at the antennas, and determining a modulation and coding scheme based on the signal to interference and noise ratio and a receiver type; and

at least one memory unit for storing the software run on the at least one processor.