Method for CSI feedback

A base station of a cellular communications network, the base station comprising:

• at least one transmitter;
• at least one receiver;
• at least one processor;
• and
• memory storing software instructions executable by the at least one processor whereby the base station is operative to:
• configure, via the at least one transmitter via a Radio Resource Control (RRC) message, a wireless device with a set of non-zero power Channel State Information Reference Signal (CSI-RS) resources, and a set of Channel State Information Interference Measurement (CSI-IM) resources;
• dynamically configure, via the at least one transmitter, a non-zero power CSI-RS resource from the set of non-zero power CSI-RS resources for measurement and dynamically configure a CSI-IM resource from the set of CSI-IM resources for interference measurement via a Downlink Control Information (DCI) message;
• receive, via the at least one receiver, an acknowledgement from the wireless device that indicates that the dynamic configuration of the non-zero power CSI-RS resource was received by the wireless device;
• receive, via the at least one receiver, a CSI report from the wireless device determined from the non-zero power CSI-RS resource dynamically configured for measurement and the CSI-IM resource dynamically configured for interference measurement;
• and
• discard any CSI reports received from the wireless device for a predefined amount of time after receiving the acknowledgement from the wireless device.