Successive interference cancellation receiver processing with selection diversity

• US 7,457,639 B2
• Filed: 05/24/2005
• Issued: 11/25/2008
• Est. Priority Date: 09/23/2003
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kadous, Tamer, Subramaniam, Anand D.
• Primary Examiner(s): Nguyen; Lee
• Application Number:
  US11/137,982
• Publication Number:
  US 20050215264A1
• Time in Patent Office: 1,281 Days
• Field of Search: 455/562.1, 455101-103, 455/272, 455/67.11, 370334-335, 370/319, 370/344, 375/260, 375/267, 375/299
• US Class Current: 455/562.1
• CPC Class Codes: H04B 7/0602 using antenna switching H04B7/0686 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/0802 using antenna selection H04B7/0868 takes precedence; antenna beam directivity switching H01Q3/24
• 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 1/0687 Full feedback

Abstract

Techniques are provided to support successive interference cancellation (SIC) receiver processing with selection diversity whereby each of N_T transmit antennas may be turned on or off. One symbol stream may be transmitted from each transmit antenna. A SIC receiver recovers the transmitted symbol streams in a specific order. Up to N_T! orderings are evaluated. For each ordering, N_T post-detection SNRs are obtained for N_T transmit antennas and used to determine N_T data rates, where the data rate is zero if the post-detection SNR is worse than a minimum required SNR. An overall data rate is computed for each ordering based on the N_T data rates. The ordering with the highest overall data rate is selected for use. Up to N_T symbol streams are processed at the data rates for the selected ordering and transmitted. The transmitted symbol streams are recovered in accordance with the selected ordering.

Claims

1. A method of determining a data transmission in a multiple-input multiple-output (MIMO) communication system, comprising:

determining a data rate for each of a plurality of transmit antennas, for each order of a plurality of orders of decoding a plurality of symbol streams based on a post-detection SNR, wherein a transmit antenna may have a data rate of zero;

computing an overall data rate for each order for the plurality of transmit antennas based on each data rate of a plurality of data rates for each order; and

selecting one order of the plurality of orders based on each of the overall data rates.

2. The method of claim 1, wherein the plurality of orders is equal to no more than N_T!, where N_T is a number of transmit antennas.

3. The method of claim 1, further comprising selecting a discrete data rate, for each order, of a set of discrete data rates based upon the computed overall data rate for each order.

4. The method of claim 1, wherein the one order includes at least one data rate for at least one of the plurality of antennas that is zero.

5. The method of claim 1, wherein determining the data rate comprises setting the data rate to zero if post-detection SNR is below a minimum required SNR.

6. The method of claim 1, wherein the one order has a greater overall data rate than each of other of the plurality of orders.

7. An apparatus in a multiple-input multiple-output (MIMO) communication system comprising

a memory;

and

a processor coupled with the memory, the processor operative to select one order decoding a plurality of symbol streams according an overall data rate of each of the plurality of orders, wherein the overall data rate for each order corresponds to a plurality of data rates for each of a plurality of transmit antennas, wherein a transmit antenna may have a data rate of zero.

8. The apparatus of claim 7, wherein a number of the plurality of orders is less than N_T!, where N_T is a number of transmit antennas.

9. The apparatus of claim 7, wherein at least one data rate of the plurality of data rates for one order includes at least one data rate of zero.

10. The apparatus of claim 7, wherein the memory is operative to store a set of discrete data rates supported by the system and a set of required SNRs for the set of discrete data rates.

11. The apparatus of claim 7, wherein the processor is operative to evaluate each of the plurality of orders based on channel response information and noise estimates.

12. The apparatus of claim 7, wherein the processor is operative to set the data rate to zero if post-detection SNR is below a minimum required SNR.

13. The apparatus of claim 7, wherein the one order has a greater overall data rate than each of other of the plurality of orders.

14. An apparatus in a multiple-input multiple-output (MIMO) communication system, comprising:

means for determining a data rate for each of a plurality of transmit antennas, for each order of a plurality of orders of decoding a plurality of symbol streams, wherein a transmit antenna may have a data rate of zero;

means for computing an overall data rate for each order for the plurality of transmit antennas based on each data rate of a plurality of data rates for each order; and

means for selecting one order of the plurality of orders based on each of the overall data rates.

15. The apparatus of claim 14, wherein the means for determining further comprises means for determining the data rate based on a post-detection SNR.

16. The apparatus of claim 14, wherein the plurality of orders is equal to no more than N_T!, where N_T is a number of transmit antennas.

17. The apparatus of claim 14, further comprising means for selecting a discrete data rate, for each order, of a set of discrete data rates based upon the computed overall data rate for each order.

18. The apparatus of claim 14, wherein the one order includes at least one data rate for at least one of the plurality of antennas that is zero.

19. The apparatus of claim 14, wherein the one order has a greater overall data rate than each of other of the plurality of orders.

20. A processor-readable medium encoded with instructions for determining a data transmission in a multiple-input multiple-output (MIMO) communication system, the instructions comprising code for:

determining a data rate for each of a plurality of transmit antennas, for each order of a plurality of orders of decoding a plurality of symbol streams based on a post-detection SNR, wherein a transmit antenna may have a data rate of zero;

computing an overall data rate for each order for the plurality of transmit antennas based on each data rate of a plurality of data rates for each order; and

selecting one order of the plurality of orders based on each of the overall data rates.