Method and apparatus for partial CSI reporting

A method performed by a user equipment, the method comprising:

• determining, by the user equipment, which channel state information reporting configuration is applicable for a partial information update, wherein the determining comprises deducing that the partial information update is enabled based on the channel state information reporting configuration including (i) at least two different configured reporting quantities comprising a first reporting quantity including channel state information-reference signal resource indicator (CRI), precoding matrix indicator (PMI), rank indicator (RI), and channel quality indicator (CQI), and a second reporting quantity comprising CQI-only or delta-CQI, and (ii) at least two configured uplink CSI reporting resources having different periodicities;
• examining, by the user equipment, whether a current channel state information reporting configuration is applicable for a partial information update, wherein the examining comprises comparing a currently determined CRI to a stored reference CRI derived from a most recently transmitted complete channel state information report;
• based on the examining, transmitting, by the user equipment, a channel state information report containing partial information update, wherein the partial information update consists of transmitting only the CQI or the delta-CQI on a physical uplink control channel (PUCCH) resource having a shortest configured periodicity while assuming the stored reference CRI, PMI, and RI for CQI computation;
• and
• providing, by the user equipment, an indication that a channel state information-reference signal resource indicator and a precoding matrix indicator and a rank indicator has changed compared to their respective reference values, in a dedicated field in uplink control information or via an indication of a reserved codepoint of a channel quality indicator or as a difference between a previous value of the channel quality indicator and a current value of the channel quality indicator.