Method and apparatus for allocating uplink resources in a multiple-input multiple-output (MIMO) communication system

• US 7,047,016 B2
• Filed: 05/16/2001
• Issued: 05/16/2006
• Est. Priority Date: 05/16/2001
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Howard, Steven J., Wallace, Mark S., Walton, Jay Rod
• Primary Examiner(s): Gesesse, Tilahun
• Assistant Examiner(s): Trinh, Tan
• Application Number:
  US09/859,346
• Publication Number:
  US 20020177447A1
• Time in Patent Office: 1,826 Days
• Field of Search: 455/33.4, 455/56.1, 455/266, 455/512, 455/166.2, 455/452.1, 455/450, 455/452.2, 455/464, 370/335, 370/342, 370/329, 370/469
• US Class Current: 455/452.1
• 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 7/0697 using spatial multiplexing
• CPC Class Codes: H04B 7/0891 Space-time diversity rake receivers H04B1/7115; space-time decoding H04L1/0631
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 72/121 for groups of terminals or users

Abstract

Techniques to schedule uplink data transmission for a number of terminals in a wireless communication system. In one method, a number of sets of terminals are formed for possible data transmission, with each set including a unique combination of terminals and corresponds to a hypothesis to be evaluated. The performance of each hypothesis is evaluated (e.g., based on channel response estimates for each terminal) and one of the evaluated hypotheses is selected based on the performance. The terminals in the selected hypothesis are scheduled for data transmission. A successive cancellation receiver processing scheme may be used to process the signals transmitted by the scheduled terminals. In this case, one or more orderings of the terminals in each set may be formed, with each terminal ordering corresponding to a sub-hypothesis to be evaluated. The performance of each sub-hypothesis is then evaluated and one of the sub-hypotheses is selected.

Claims

1. A method for scheduling uplink data transmission for a plurality of terminals in a wireless communication system, comprising:

forming one or more sets of terminals for possible transmission on a channel, wherein each set includes a unique combination of terminals and corresponds to a hypothesis to be evaluated;

evaluating performance of each hypothesis;

selecting one of the one or more evaluated hypotheses based on their performance; and

scheduling the terminals in the selected hypothesis for data transmission on the channel, wherein the one or more sets are formed from terminals of a plurality of types, wherein each terminal of a first type is capable of transmitting a single data stream on a single transmission channel and each terminal of a second type is capable of transmitting multiple independent data streams on multiple transmission channels.

2. The method of claim 1, further comprising:

determining data rates for each data stream of each terminal in the selected hypothesis, and

wherein data is transmitted at the determined data rates from the terminals in the selected hypothesis.

3. The method of claim 1, further comprising:

determining a coding and modulation scheme to be used for each data stream of each terminal in the selected hypothesis, and

wherein data is processed based on the determined coding and modulation schemes prior to transmission.

4. The method of claim 1, wherein each hypothesis is evaluated based in part on channel response estimates for each terminal in the hypothesis, wherein the channel response estimates are indicative of channel characteristics between the terminal and a receiving system.

5. The method of claim 1, wherein the channel response estimates comprise signal-to-noise-plus-interference ratios (SNRs).

6. The method of claim 1, wherein the evaluating includes

computing a performance metric for each hypothesis.

7. The method of claim 6, wherein the performance metric is a function of throughput achievable by each of the terminals in the hypothesis.

8. The method of claim 6, wherein the hypothesis having the best performance metric is selected for scheduling.

9. The method of claim 1, further comprising:

prioritizing the terminals to be considered for scheduling.

10. The method of claim 9, further comprising:

limiting terminals to be processed for scheduling to a group of N highest priority terminals.

11. The method of claim 9, further comprising:

maintaining one or more metrics for each terminal to be considered for scheduling, and

wherein the priority of each terminal is determined based in part on the one or more metrics maintained for the terminal.

12. The method of claim 11, wherein one metric maintained for each terminal relates to an average throughput rate achieved by the terminal.

13. The method of claim 1, wherein each transmission channel corresponds to a spatial subchannel in the communication system.

14. The method of claim 1, wherein each of the one or more sets includes terminals having similar link margins.

15. A method for scheduling data transmission for a plurality of terminals in a wireless communication system, comprising:

forming one or more sets of terminals for possible transmission on a channel, wherein each set includes a unique combination of terminals and corresponds to a hypothesis to be evaluated;

forming one or more orderings of the terminals in each set, wherein each terminal ordering corresponds to a sub-hypothesis to be evaluated;

evaluating performance of each sub-hypothesis;

selecting one of the plurality of evaluated sub-hypotheses based on their performance;

scheduling the terminals in the selected sub-hypothesis for data transmission on the channel, and

wherein signals transmitted from the scheduled terminals are processed in an order defined by the selected sub-hypothesis.

16. The method of claim 15, wherein the evaluating includes

processing a signal hypothetically transmitted from each terminal in the sub-hypothesis based on a particular receiver processing scheme to provide a post-processed signal, and

determining a signal-to-noise-plus-interference ratio (SNR) for the post-processed signal for each terminal in the sub-hypothesis.

17. The method of claim 15, wherein one sub-hypothesis is formed for each hypothesis, and wherein the ordering in the sub-hypothesis is selected based on priority of terminals in the hypothesis.

18. The method of claim 17, wherein a lowest priority terminal in the hypothesis is processed first and a highest priority terminal is processed last.

19. The method of claim 15, wherein one sub-hypothesis is formed for each hypothesis, and wherein the ordering in the sub-hypothesis is selected to achieve the best performance for the hypothesis.