Aperiodic triggering of channel quality information using physical downlink control channel
View Patent ↗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 channel quality information (CQI) acquiring method comprising:
transmitting CQI control information consisting of a plurality of bits to a terminal apparatus, 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 further indicating a resource indication specifying one or more downlink component carriers among a plurality of downlink component carriers, for said one or more downlink component carriers the CQI report is requested, wherein a combination of the plurality of bits jointly indicates both the CQI report request and the resource indication and no one bit of the plurality of bits alone indicates the CQI report request; and
receiving, when the CQI report is requested, the CQI report for said one or more downlink component carriers specified by the resource indication.
2. The CQI acquiring method according to claim 1 , wherein the plurality of bits are two bits.
3. The CQI acquiring method according to claim 2 , wherein the combination of the two bits includes a first combination which indicates that the CQI report is not requested and a second combination which indicates that the CQI report is requested for a downlink component carrier on which the CQI control information was transmitted.
4. The CQI acquiring method according to claim 1 , wherein the CQI report request is a request for an aperiodic CQI report.
5. The CQI acquiring method according to claim 1 , wherein the CQI report is to be transmitted over a physical uplink shared channel (PUSCH).
6. A base station apparatus comprising:
transmitting section configured to transmit CQI control information consisting of a plurality of bits to a terminal apparatus, 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 further indicating a resource indication specifying one or more downlink component carriers among a plurality of downlink component carriers, for said one or more downlink component carriers the CQI report is requested, wherein a combination of the plurality of bits jointly indicates both the CQI report request and the resource indication and no one bit of the plurality of bits alone indicates the CQI report request; and
receiving section configured to receive, when the CQI report is requested, the CQI report for said one or more downlink component carriers specified by the resource indication.
7. The base station apparatus according to claim 6 , wherein the plurality of bits are two bits.
8. The base station apparatus according to claim 7 , wherein the combination of the two bits includes a first combination which indicates that the CQI report is not requested and a second combination which indicates that the CQI report is requested for a downlink component carrier on which the CQI control information was transmitted.
9. The base station apparatus according to claim 6 , wherein the CQI report request is a request for an aperiodic CQI report.
10. The base station apparatus according to claim 6 , wherein the CQI report is to be transmitted over a physical uplink shared channel (PUSCH).