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

• US 7,248,879 B1
• Filed: 10/29/2003
• Issued: 07/24/2007
• Est. Priority Date: 05/16/2001
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Howard, Steven J., Wallace, Mark, Walton, Jay R.
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US10/696,630
• Time in Patent Office: 1,364 Days
• Field of Search: 455450-4522, 455/561, 455/562.1, 455/69, 455101-103, 455/509, 455/513, 375/347, 375/349, 370/310, 370/329, 370/431
• US Class Current: 455/452.2
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/061 using feedback from receiving side
• 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 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04W 16/00 Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 84/14 WLL [Wireless Local Loop]; RLL [Radio Local Loop]

Abstract

Techniques to schedule downlink data transmission to a number of terminals in a wireless communication system. In one method, one or more sets of terminals are formed for possible data transmission, with each set including a unique combination of one or more terminals and corresponding to a hypothesis to be evaluated. One or more sub-hypotheses may further be formed for each hypothesis, with each sub-hypothesis corresponding to specific assignments of a number of transmit antennas to the one or more terminals in the hypothesis. The performance of each sub-hypothesis is then evaluated, and one of the evaluated sub-hypotheses is selected based on their performance. The terminal(s) in the selected sub-hypothesis are then scheduled for data transmission, and data is thereafter coded, modulated, and transmitted to each scheduled terminal from one or more transmit antennas assigned to the terminal.

Claims

1. A method for scheduling data transmission in a wireless communication system, the method comprising:

identifying one or more sets of terminals, each set including one or more terminals and corresponding to a hypothesis to be evaluated based on one or more criteria;

assigning a plurality of transmit antennas to the one or more terminals in each set;

evaluating performance of each hypothesis based on channel state information (CSI) associated with each terminal, the CSI being indicative of channel characteristics between the respective terminal and the corresponding transmit antennas; and

selecting at least one set of terminals to receive data transmission based, at least in part, on the performance of each hypothesis.

2. The method of claim 1 further comprising:

scheduling data transmission to the one or more terminals in the selected set.

3. The method of claim 1 wherein each hypothesis comprises a plurality of sub-hypotheses each of which corresponding to one or more specific assignments of the transmit antennas to the one or more terminals in the respective set and wherein the performance of each hypothesis is evaluated based on performance of the corresponding sub-hypotheses.

4. The method of claim 1, wherein the CSI for each terminal comprises signal-to-noise-plus-interference ratio (SNR) estimates derived at the respective terminal based on signals transmitted from the transmit antennas.

5. The method of claim 1, wherein the evaluating includes:

computing a performance metric for each hypothesis as a function of throughput achievable by each terminal in the respective set.

6. The method of claim 1, wherein the plurality of transmit antennas are assigned to the one or more terminals in each set based on priority of terminals in the set.

7. The method of claim 6, wherein the priority of each terminal is determined based on one or more factors including quality of service (QoS) associated with the respective terminal.

8. An apparatus for managing data transmission in a wireless communication system, the apparatus comprising:

means for identifying one or more sets of terminals, each set including one or more terminals and corresponding to a hypothesis to be evaluated based on one or more criteria;

means for assigning a plurality of transmit antennas to the one or more terminals in each set;

means for evaluating performance of each hypothesis based on channel state information (CSI) associated with each terminal, the CSI being indicative of channel characteristics between the respective terminal and the corresponding transmit antennas; and

means for selecting at least one set of terminals to receive data transmission based, at least in part, on the performance of each hypothesis.

9. The apparatus of claim 8 further comprising:

means for scheduling data transmission to the one or more terminals in the selected set.

10. The apparatus of claim 8 wherein each hypothesis comprises a plurality of sub-hypotheses each of which corresponding to one or more specific assignments of the transmit antennas to the one or more terminals in the respective set and wherein the performance of each hypothesis is evaluated based on performance of the corresponding sub-hypotheses.

11. The apparatus of claim 8, wherein the CSI for each terminal comprises signal-to-noise-plus-interference ratio (SNR) estimates derived at the respective terminal based on signals transmitted from the transmit antennas.

12. The apparatus of claim 8, wherein means for evaluating includes:

means for computing a performance metric for each hypothesis as a function of throughput achievable by each terminal in the respective set.

13. The apparatus of claim 8, wherein the plurality of transmit antennas are assigned to the one or more terminals in each set based on priority of terminals in the set.

14. The apparatus of claim 13, wherein the priority of each terminal is determined based on one or more factors including quality of service (QoS) associated with the respective terminal.