Partial CQI feedback in wireless networks
Within a wireless network, feedback information from user equipment (UE) to a control node (eNodeB) is necessary to support various functions. A UE receives an allocation from the eNodeB comprising a plurality of periodic transmission instances for a channel quality indicator (CQI) and a schedule comprising a plurality of periodic transmission instances for a rank indicator (RI), wherein the CQI comprises RI and other CQI fields. The UE then transmits an RI without transmitting the other CQI fields in a transmission instance allocated for both RI and other CQI fields.
1 . A method comprising:
receiving an allocation indicative of a plurality of periodic transmission instances for reporting a channel quality indicator (CQI);
receiving an allocation indicative of a plurality of periodic transmission instances for reporting a rank indicator (RI);
coding a first RI report with one of a rate (20, 1) or a rate (20, 2) coding scheme; and
transmitting the coded first RI report without transmitting a CQI report in a first transmission instance allocated for both reporting an RI and reporting a CQI.
2 . The method of claim 1 , wherein an ACK/NAK and the first RI report are transmitted in the first transmission instance, and wherein the ACK/NAK is transmitted by modulating a reference signal (RS) of the first transmission instance.
3 . The method of claim 1 , further comprising transmitting a first CQI report in a second transmission instance allocated for reporting a CQI.
4 . The method of claim 3 , wherein the first CQI report includes a value indicative of a modulation scheme and a precoding matrix indicator (PMI).
5 . The method of claim 3 , wherein the first CQI report includes a value indicative of a modulation scheme.
6 . The method of claim 3 , wherein a same channel resource is used for the transmission of both the first RI report and the first CQI report.
7 . The method of claim 6 , wherein the same channel resource corresponds to a selected cyclic shift of a sequence within a physical resource block.
8 . The method of claim 6 , wherein the first RI report and the first CQI report are transmitted on a Physical Uplink Control Channel (PUCCH).
9 . The method of claim 1 , wherein the rate (20, 1) or the rate (20, 2) coding scheme is applied to code the first RI report depending on a number of rank bits in the first RI report.
10 . The method of claim 1 , wherein coding the first RI report with one of a rate (20, 1) or a rate (20, 2) coding scheme includes coding the first RI report with the rate (20, 1) coding scheme.
11 . The method of claim 1 , wherein coding the first RI report with one of a rate (20, 1) or a rate (20, 2) coding scheme includes coding the first RI report with the rate (20, 2) coding scheme.
12 . The method of claim 1 , wherein a reporting interval for reporting RI is longer than a reporting interval for reporting CQI.
13 . The method of claim 1 , wherein the first transmission instance is a subframe.
14 . The method of claim 1 , wherein a length of information bits for the CQI depends on the RI.
15 . The method of claim 1 , wherein transmitting the coded first RI report includes transmitting the coded first RI report using single carrier frequency division multiple access (SC-FDMA) symbols.
16 . The method of claim 1 , further comprising transmitting both a second RI report and a CQI report in a second transmission instance allocated for both reporting an RI and reporting a CQI.
17 . A user equipment (UE) comprising:
a transceiver configured to receive an allocation indicative of a plurality of periodic transmission instances for reporting a channel quality indicator (CQI), and to receive an allocation indicative of a plurality of periodic transmission instances for reporting a rank indicator (RI); and
a processor configured to code a first RI report with one of a rate ( 20 , 1 ) or a rate ( 20 , 2 ) coding scheme,
wherein the transceiver is further configured to transmit the coded first RI report without transmitting a CQI report in a first transmission instance allocated for both reporting an RI and reporting a CQI.
18 . The UE of claim 17 , wherein an ACK/NAK is transmitted in the first transmission instance, and wherein the ACK/NAK is transmitted by modulating a reference signal (RS) of the first transmission instance.
19 . The UE of claim 17 , wherein the transceiver is further configured to transmit a first CQI report in a second transmission instance allocated for reporting a CQI.
20 . The UE of claim 19 , wherein the first CQI report includes a value indicative of a modulation scheme and a precoding matrix indicator (PMI).
21 . The UE of claim 19 , wherein the first CQI report includes a value indicative of a modulation scheme.
22 . The UE of claim 19 , wherein a same channel resource is used for the transmission of both the first RI report and the first CQI report.
23 . The UE of claim 22 , wherein the same channel resource corresponds to a selected cyclic shift of a sequence within a physical resource block.
24 . The UE of claim 22 , wherein the first RI report and the first CQI report are transmitted on a Physical Uplink Control Channel (PUCCH).
25 . The UE of claim 17 , wherein the rate (20, 1) or the rate (20, 2) coding scheme is applied to code the first RI report depending on a number of rank bits in the first RI report.
26 . The UE of claim 17 , wherein the processor is further configured to code the first RI report with the rate (20, 1) coding scheme.
27 . The UE of claim 17 , wherein the processor is further configured to code the first RI report with the rate (20, 2) coding scheme.
28 . The UE of claim 17 , wherein a reporting interval for reporting RI is longer than a reporting interval for reporting CQI.
29 . The UE of claim 17 , wherein the first transmission instance is a subframe.
30 . The UE of claim 17 , wherein a length of information bits for the CQI depends on the RI.
31 . The UE of claim 17 , wherein the transceiver is further configured to transmit the coded first RI report includes transmitting the coded first RI report using single carrier frequency division multiple access (SC-FDMA) symbols.
32 . The UE of claim 17 , wherein the transceiver is further configured to transmit both a second RI report and a CQI report in a second transmission instance allocated for both reporting an RI and reporting a CQI.