Methods and arrangements for CSI reporting

• US 9,749,111 B2
• Filed: 07/01/2016
• Issued: 08/29/2017
• Est. Priority Date: 05/10/2012
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Hammarwall, David
• Primary Examiner(s): Nooristany, Sulaiman
• Application Number:
  US15/201,183
• Publication Number:
  US 20170070334A1
• Time in Patent Office: 424 Days
• Field of Search: None
• 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 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04J 11/0053 using co-ordinated multipoint transmission/reception co-ordinated antenna or beam-forming aspects H04B7/022
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0028 Formatting
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/03898 codebook-based design selection of codebook or precoding matrix for MIMO diversity systems H04B7/0456
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI

Abstract

A method in a wireless device for reporting Channel State Information (CSI). The wireless device is comprised in a wireless communications system. The method includes receiving a CSI process configuration and a request for CSI information from a network node. The method further includes reporting CSI for one or more CSI processes. The CSI reflects the state of the channel for a CSI reference resource. According to the method, the CSI reference resource is determined based on the number of configured CSI processes. Related devices are also disclosed.

Claims

1. A method, in a wireless device, for reporting Channel State Information (CSI), the wireless device being comprised in a wireless communications system, the method comprising:

receiving, from a network node, a CSI process configuration and a request for CSI;

determining a subframe for a CSI reference resource based at least in part on a number of configured CSI processes, wherein a difference between the subframe for the CSI reference resource and a subframe in which a CSI report is transmitted increases when the number of configured CSI processes exceeds a certain threshold; and

reporting CSI for one or more CSI processes by transmitting the CSI report, wherein the reported CSI reflects a state of a channel for the CSI reference resource.

2. The method of claim 1, wherein the determining the subframe for the CSI reference resource comprises determining the location of the subframe for the CSI reference resource.

3. The method of claim 1, wherein the determining a subframe comprising determining a location of the subframe for the CSI reference resource relative to a subframe in which the CSI report is transmitted.

4. The method of claim 3, wherein the location is represented by a number N, and N increases based on the amount of configured CSI processes.

5. The method of claim 3, wherein the location is represented by a number N, and N is applied to all CSI processes configured for the wireless device.

6. The method of claim 1, further comprising:

prioritizing a first CSI process over a second CSI process;

determining a rank indicator and/or a precoding matrix indicator for the first CSI process; and

reusing the determined rank indicator and/or precoding matrix indicator for the second CSI process.

7. The method of claim 1, further comprising:

performing measurements on reference signal resources corresponding to the configured CSI processes; and

determining the reported CSI based on the measurements.

8. The method of claim 1, wherein the reported CSI is determined based on measurements performed in and/or prior to the CSI reference resource.

9. The method of claim 1, wherein the request for CSI is a request for a periodic CSI report, or a request for an aperiodic CSI report.

10. The method of claim 1, further comprising:

performing measurements on interference measurement resources corresponding to the configured CSI processes; and

determining the reported CSI based on the measurements.

11. The method of claim 1, wherein a CSI process is a process by which CSI is reported for at least a reference signal resource.

12. The method of claim 1, wherein the determining the subframe for the CSI reference resource is further based on a number of configured CSI reference resources.

13. A wireless device for reporting Channel State Information (CSI), the wireless device comprising:

memory comprising instructions;

processing circuitry operatively connected to the memory and configured, when executing the instructions, to cause the wireless device to;

receive, from a network node, a CSI process configuration and a request for CSI;

determine a subframe for a CSI reference resource based at least in part on a number of configured CSI processes, wherein a difference between the subframe for the CSI reference resource and a subframe in which a CSI report is transmitted increases when the number of configured CSI processes exceeds a certain threshold; and

report CSI for one or more CSI processes by transmitting the CSI report, wherein the reported CSI reflects a state of a channel for the CSI reference resource.

14. The wireless device of claim 13, wherein the wireless device is a user equipment.

15. The wireless device of claim 13, wherein the processing circuitry, when executing the instructions, is further configured to determine the location of the CSI reference resource further based on a number of configured CSI-RS resources.

16. The wireless device of claim 13, wherein the processing circuitry, when executing the instructions, is further configured to:

prioritize a first CSI process over a second CSI process;

determine a rank indicator and/or a precoding matrix indicator for the first CSI process;

reuse the determined rank indicator and/or precoding matrix indicator for the second CSI process.

17. The wireless device of claim 13, wherein the processing circuitry, when executing the instructions, is further configured to:

perform measurements on reference signal resources corresponding to the configured CSI processes;

determine the reported CSI based on the measurements.

18. The wireless device of claim 13, wherein the processing circuitry, when executing the instructions, is further configured to determine the reported CSI based on measurements performed in and/or prior to the CSI reference resource.

19. The wireless device of claim 13, wherein the processing circuitry, when executing the instructions, is further configured to:

perform measurements on interference measurement resources corresponding to the configured CSI processes;

determine the reported CSI based on the measurements.

20. The wireless device of claim 13, wherein a CSI process is a process by which CSI is reported for at least a reference signal resource.