Methods and arrangements for CSI reporting

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.