Method and an apparatus for providing channel quality information in a wireless communication system
A method and an apparatus for providing channel quality information in a wireless communication system are disclosed. According to one embodiment of the invention, a method for transmitting channel quality information includes receiving a downlink signal, calculating a channel quality information index for the received downlink signal at least based on a number of resource elements for a physical downlink shared channel (PDSCH), wherein the number of resource elements for the PDSCH is determined at least based on an overhead of a demodulation reference signal (DMRS), and transmitting the calculated channel quality information index.
1. A method for transmitting a channel quality indicator (CQI) by a user equipment (UE), the method comprising:
receiving information related to periodic channel state information (CSI) reporting via higher layer signaling;
determining a CQI index included in the periodic CSI reporting, wherein determining the CQI index comprises calculating the CQI index according to:
a number of resource elements allocated to a physical downlink shared channel (PDSCH) in a subframe and a number of resource elements allocated to demodulation reference signals (DM-RSs) in the subframe; and
an assumption that no resource element is allocated for a CSI-reference signal (CSI-RS); and
transmitting the determined CQI index.
2. The method of claim 1 , wherein the CQI index is determined based on a number of orthogonal frequency-division multiplexing (OFDM) symbols allocated for control signaling in the subframe.
3. The method of claim 1 , further comprising:
determining:
the number of resource elements allocated to the DM-RSs in the subframe based on a rank value; and
the number of resource elements allocated to the PDSCH in the subframe based on the number of resource elements allocated to the DM-RSs, wherein:
the number of resource elements allocated to the DM-RSs within one resource block of the subframe is 12 resource elements for the rank value of 1 or 2; and
the number of resource elements allocated to the DM-RSs within the one resource block of the subframe is 24 resource elements for the rank value of 3, 4, 5, 6, 7 or 8.
4. The method of claim 1 , wherein the UE is configured for reporting at least one of a Precoding Matrix Indicator (PMI) or a Rank Indicator (RI).
5. The method of claim 1 , wherein the information related to periodic CSI reporting includes a transmission period of the periodic CSI reporting and an offset for the transmission period in subframe units.
6. The method of claim 1 , wherein the determined CQI index is transmitted to a base station on a Physical Uplink Control Channel (PUCCH).
7. A user equipment (UE) for transmitting a channel quality indicator (CQI), the UE comprising:
a receiver configured to receive a downlink signal from a base station (BS);
a transmitter configured to transmit an uplink signal to the B S; and
a processor configured to be connected to the receiver and transmitter and to control operations of the UE, wherein the processor is further configured to:
receive information related to periodic channel state information (CSI) reporting via higher layer signaling;
determine a CQI index included in the periodic CSI reporting, wherein the processor is configured to determine the CQI index by calculating the CQI index according to:
a number of resource elements allocated to a physical downlink shared channel (PDSCH) in a subframe and a number of resource elements allocated to demodulation reference signals (DM-RSs) in the subframe; and
an assumption that no resource element is allocated for a CSI-reference signal (CSI-RS); and
control the transmitter to transmit the determined CQI index.
8. The UE of claim 7 , wherein the CQI index is determined based on a number of orthogonal frequency-division multiplexing (OFDM) symbols allocated for control signaling in the subframe.
9. The UE of claim 7 , wherein the processor is further configured to:
determine:
the number of resource elements allocated to the DM-RSs in the subframe based on a rank value; and
the number of resource elements allocated to the PDSCH in the subframe based on the number of resource elements allocated to the DM-RSs, wherein:
the number of resource elements allocated to the DM-RSs within one resource block of the subframe is 12 resource elements for the rank value of 1 or 2; and
the number of resource elements allocated to the DM-RSs within the one resource block of the subframe is 24 resource elements for the rank value of 3, 4, 5, 6, 7 or 8.
10. The UE of claim 7 , wherein the UE is configured for reporting at least one of a Precoding Matrix Indicator (PMI) or a Rank Indicator (RI).
11. The UE of claim 7 , wherein the information related to the periodic CSI reporting includes a transmission period of the periodic CSI reporting and an offset for the transmission period in subframe units.
12. The UE of claim 7 , wherein the determined CQI index is transmitted to a base station on a Physical Uplink Control Channel (PUCCH).
13. A wireless communication device for transmitting a channel quality indicator (CQI), comprising:
at least one processor configured to:
receive information related to periodic channel state information (CSI) reporting via higher layer signaling;
determine a CQI index included in the periodic CSI reporting, wherein the at least one processor is configured to determine the CQI index by calculating the CQI index according to:
a number of resource elements allocated to a physical downlink shared channel (PDSCH) in a subframe and a number of resource elements allocated to demodulation reference signals (DM-RSs) in the subframe; and
an assumption that no resource element is allocated for a CSI-reference signal (CSI-RS); and
transmit the determined CQI index.
14. The wireless communication device of claim 13 , wherein the CQI index is determined based on a number of orthogonal frequency-division multiplexing (OFDM) symbols allocated for control signaling in the subframe.
15. The wireless communication device of claim 13 , wherein the at least one processor is further configured to:
determine:
the number of resource elements allocated to the DM-RSs in the subframe based on a rank value; and
the number of resource elements allocated to the PDSCH in the subframe based on the number of resource elements allocated to the DM-RSs, wherein:
the number of resource elements allocated to the DM-RSs within one resource block of the subframe is 12 resource elements for the rank value of 1 or 2; and
the number of resource elements allocated to the DM-RSs within the one resource block of the subframe is 24 resource elements for the rank value of 3, 4, 5, 6, 7 or 8.
16. The wireless communication device of claim 13 , wherein the processor is configured for reporting at least one of a Precoding Matrix Indicator (PMI) or a Rank Indicator (RI).
17. The wireless communication device of claim 13 , wherein the information related to periodic CSI reporting includes a transmission period of the periodic CSI reporting and an offset for the transmission period in subframe units.
18. The wireless communication device of claim 13 , wherein the determined CQI index is transmitted to a base station on a Physical Uplink Control Channel (PUCCH).