Dynamic channel state information reference signals (CSI-RS) resource mapping configuration for precoded channel state information reference signals (CSI-RS) configurations

A method, comprising:

• determining, at a network node, information relating to an actual number of ports configured for a user equipment for channel measurements;
• determining a pool of channel state information reference signal (CSI-RS) resources for the user equipment, wherein the pool of channel state information reference signal (CSI-RS) resources is provided in a radio resource control (RRC) configuration and includes the actual number of ports;
• and
• transmitting, to the user equipment, an RRC configuration comprising a list of a plurality of N possible CSI-RS resource mappings, a medium access (MAC) control element (CE) comprising a plural subset Nα of the plurality of N possible CSI-RS resource mappings that are activated, and downlink control information (DCI) comprising an indication of which of the plural subset Nα of active resource mappings is to be selected as an existing resource mapping, and transmitting one or two shift values by which the user equipment learns that the user equipment should shift the existing resource mapping in frequency and/or time inside the physical resource block (PRB), wherein the resource mapping is performed over different sub-groups of CSI-RS resources and the different sub-groups of CSI-RS resources are updated at different times.

A method, comprising:

• receiving, from a network node, fixed channel state information reference signal (CSI-RS) mapping in radio resource control (RRC), wherein the radio resource control (RRC) comprises a list of a plurality of N possible CSI-RS resource mappings;
• receiving, from the network node, a medium access (MAC) control element (CE) comprising a plural subset Nα of the plurality of N possible CSI-RS resource mappings that are activated, downlink control information (DCI) comprising an indication of which of the plural subset Nα of active resource mappings is to be selected as a first channel state information reference signal (CSI-RS) mapping, and updated user equipment specific offset from the medium access control (MAC)-control element (CE) or the downlink control information (DCI) and computing new channel state information reference signal (CSI-RS) mapping, wherein the new channel state information reference signal (CSI-RS) mapping is performed over different sub-groups of CSI-RS resources and the different sub- groups of CSI-RS resources are updated at different times;
• using the new channel state information reference signal (CSI-RS) mapping to receive channel state information reference signal (CSI-RS) on new locations and obtaining an estimate of channel frequency response (CFR);
• deriving channel state information (CSI) feedback report from the CFR;
• and
• providing CSI feedback information to the network node.