Aperiodic triggering of channel quality information using physical downlink control channel
The invention relates methods for triggering channel quality feedback for at least one of plural component carriers of a communication system available for downlink transmission. The invention suggests a mechanism for triggering channel quality feedback from a terminal where the downlink control signaling overhead for the selection of component carrier(s) to be reported on is minimized. One aspect of the invention is a new interpretation of a predetermined format for dedicated control information comprising a CQI request flag, which is depending on the status of the CQI request flag. In case the CQI request flag is set at least one further bit of the dedicated control information is interpreted as information indicative of the one or more component carriers available for downlink transmission to the terminal and the terminal is providing channel quality feedback on the channel quality experienced on the indicated component carrier or component carriers.
1. A communication apparatus comprising:
a receiver, which in operation, receives Channel Quality Information (CQI) control information consisting of a plurality of bits in a downlink control information (DCI) format, the plurality of bits indicating a CQI report request specifying whether a CQI report is requested or not and, when the CQI report is requested, the plurality of bits jointly indicating both the CQI report request and a resource indication specifying one or more downlink component carriers, among a plurality of downlink component carriers, for which the CQI report is requested, wherein no one bit of the plurality of bits alone indicates the CQI report request; and
a transmitter, which in operation, transmits the CQI report for said one or more downlink component carriers, when the CQI report is requested,
wherein the plurality of bits are capable of representing a first bit combination which indicates that the CQI report is requested for at least one downlink component carrier indicated by an RRC signaling.
2. The communication apparatus according to claim 1 , wherein the plurality of bits are two bits.
3. The communication apparatus according to claim 2 , wherein the two bits are capable of representing a second bit combination which indicates that the CQI report is not requested and a third bit combination which indicates that the CQI report is requested for a downlink component carrier on which the CQI control information is transmitted.
4. The communication apparatus according to claim 1 , wherein the CQI report request is a request for an aperiodic CQI report.
5. The communication apparatus according to claim 1 , wherein the CQI report is transmitted over a physical uplink shared channel (PUSCH).
6. The communication apparatus according to claim 1 , wherein the plurality of bits are two bits, and the two bits are capable of indicating that the CQI report is not requested or that the CQI report is requested for a downlink component carrier on which the CQI control information is transmitted.
7. A communication method comprising:
receiving Channel Quality Information (CQI) control information consisting of a plurality of bits in a downlink control information (DCI) format, the plurality of bits indicating a CQI report request specifying whether a CQI report is requested or not and, when the CQI report is requested, the plurality of bits jointly indicating both the CQI report request and a resource indication specifying one or more downlink component carriers, among a plurality of downlink component carriers, for which the CQI report is requested, wherein no one bit of the plurality of bits alone indicates the CQI report request; and
transmitting the CQI report for said one or more downlink component carriers, when the CQI report is requested,
wherein the plurality of bits are capable of representing a first bit combination which indicates that the CQI report is requested for at least one downlink component carrier indicated by an RRC signaling.
8. The communication method according to claim 7 , wherein the plurality of bits are two bits.
9. The communication method according to claim 8 , wherein the two bits are capable of representing a second bit combination which indicates that the CQI report is not requested and a third bit combination which indicates that the CQI report is requested for a downlink component carrier on which the CQI control information is transmitted.
10. The communication method according to claim 7 , wherein the CQI report request is a request for an aperiodic CQI report.
11. The communication method according to claim 7 , wherein the CQI report is transmitted over a physical uplink shared channel (PUSCH).
12. The communication method according to claim 7 , wherein the plurality of bits are two bits, and the two bits are capable of indicating that the CQI report is not requested or that the CQI report is requested for a downlink component carrier on which the CQI control information is transmitted.