Method for reporting channel state information in wireless communication system and apparatus for the same
A method of reporting, by a user equipment (UE), channel state information (CSI) in a wireless communication system, includes: receiving, by the UE and from a base station (BS), downlink control information (DCI) related to an aperiodic CSI report that is to be performed by the UE in a slot n; determining, by the UE, a value n CQI_ref based on a number of symbols Z′ related to a time for computing the CSI; determining, by the UE, a CSI reference resource as being a slot n−n CQI_ref in a time domain that is to be used for the aperiodic CSI report; and transmitting, by the UE and to the BS, the aperiodic CSI report in the slot n, based on the CSI reference resource being slot n−n CQI_ref . The CSI may be calculated by using the most recent A CSI-RS, and thereby the most recent CSI may be reported.
1. A method of reporting, by a user equipment (UE), channel state information (CSI) in a wireless communication system, the method comprising:
receiving, by the UE and from a base station (BS), downlink control information (DCI) related to an aperiodic CSI report that is to be performed by the UE in a slot n;
determining, by the UE, a value n CQI_ref based on a number of symbols Z′ related to a time for computing the CSI;
determining, by the UE, a CSI reference resource as being a slot n−n CQI_ref in a time domain that is to be used for the aperiodic CSI report; and
transmitting, by the UE and to the BS, the aperiodic CSI report in the slot n, based on the CSI reference resource being slot n−n CQI_ref ,
wherein the n CQI_ref is a smallest value greater than or equal to └Z′/N symb slot ┘ such that the slot n−n CQI_ref satisfies a valid downlink slot criteria, and
wherein └·┘ is a floor function and N symb slot is a number of symbols in one slot.
2. The method of claim 1 , wherein the valid downlink slot criteria is based at least on (i) the number of symbols Z′ related to the time for computing the CSI and (ii) a DCI processing time.
3. The method of claim 1 , wherein N symb slot is equal to 14 symbols in a slot.
4. The method of claim 1 , further comprising:
receiving, from the BS, an aperiodic reference signal (CSI-RS) in the CSI reference resource, slot n−n CQI_ref ;
determining the CSI based on the aperiodic CSI-RS; and
generating the aperiodic CSI report based on the CSI.
5. The method of claim 1 , further comprising:
determining the number of symbols Z′ related to the time for computing the CSI based on a CSI complexity and a subcarrier spacing.
6. The method of claim 5 , wherein the number of symbols Z′ does not include a DCI processing time.
7. The method of claim 1 , wherein determining the value n CQI_ref based on the number of symbols Z′ related to the time for computing the CSI comprises:
determining the value n CQI_ref based on the number of symbols Z′ related to the time for computing the CSI, and further based on a number of symbols in one slot.
8. The method of claim 1 , wherein receiving the DCI comprises:
receiving the DCI in a slot other than the slot n in which the aperiodic CSI report is to be performed.
9. The method of claim 1 , wherein, based on the value n CQI_ref being equal to zero, the aperiodic CSI report is performed in a same slot as receiving the DCI.
10. A user equipment (UE) configured to report channel state information (CSI) in a wireless communication system, the UE comprising:
a radio frequency (RF) module configured to transmit and receive radio signals;
at least one processor; and
at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising:
receiving, via the RF module and from a base station (BS), downlink control information (DCI) related to an aperiodic CSI report that is to be performed by the UE in a slot n;
determining, by the UE, a value n CQI_ref based on a number of symbols Z′ related to a time for computing the CSI;
determining, by the UE, a CSI reference resource as being a slot n−n CQI_ref in a time domain that is to be used for the aperiodic CSI report; and
transmitting, via the RF module and to the BS, the aperiodic CSI report in the slot n, based on the CSI reference resource being slot n−n CQI_ref ,
wherein the n CQI_ref is a smallest value greater than or equal to └Z′/N symb slot ┘ such that the slot n−n CQI_ref satisfied a valid downlink slot criteria, and
wherein └·┘ is a floor function and N symb slot is a number of symbols in one slot.
11. The UE of claim 10 , wherein the valid downlink slot criteria is based at least on (i) the number of symbols Z′ related to the time for computing the CSI and (ii) a DCI processing time.
12. The UE of claim 10 , wherein N symb slot is equal to 14 symbols in a slot.
13. The UE of claim 10 , wherein the operations further comprise:
receiving, via the RF module and from the BS, an aperiodic reference signal (CSI-RS) in the CSI reference resource, slot n−n CQI_ref ;
determining the CSI based on the aperiodic CSI-RS; and
generating the aperiodic CSI report based on the CSI.
14. The UE of claim 10 , wherein determining the number of symbols Z′ related to the time for computing the CSI comprises:
determining the number of symbols Z′ related to the time for computing the CSI based on a CSI complexity and a subcarrier spacing.
15. The UE of claim 14 , wherein the number of symbols Z′ does not include a DCI processing time.
16. The UE of claim 10 , wherein determining the value n CQI_ref based on the number of symbols Z′ related to the time for computing the CSI comprises:
determining the value n CQI_ref based on the number of symbols Z′ and further based on information related to a subcarrier spacing.
17. The UE of claim 10 , wherein receiving the DCI comprises:
receiving the DCI in a slot other than the slot n in which the aperiodic CSI report is to be performed.
18. The UE of claim 10 , wherein, based on the value n CQI_ref being equal to zero, the aperiodic CSI report is performed in a same slot as receiving the DCI.