Communication scheme for channel quality information
View Patent ↗The invention relates to a method for receiving and a method for reconstructing channel quality information in a communication system. Further, the invention also provides a transmitter and receiver performing these methods, respectively. The invention suggests a scheme for communicating channel quality measures that on the one hand allows for an accurate reconstruction of the channel quality measures at the receiver and on the other hand requires an acceptable transmission overhead. This is achieved by partitioning channel quality measures into at least two partitions and to compress the values partition-wise, for example, by means of a discrete cosine transform and the transmission of only a subset of the resulting coefficients.
1. A method for receiving, at a receiver, a periodic report of channel quality information from a transmitting entity within a communication system, the method comprising the steps of:
receiving a first channel quality information report at a first reporting instance; and
receiving a second channel quality information report at a second reporting instance;
wherein a change in a channel state triggers a change in a content of the second channel quality information report between a first content and a second content at the transmitting entity; and
wherein the first content of the second channel quality information report enables a more accurate frequency domain reconstruction of the channel state at the receiver than the second content of the second channel quality information report.
2. The method according to claim 1 , wherein the first channel quality information report is received at a first reporting period and the second channel quality information report is received at a second reporting period.
3. The method according to claim 2 , wherein the second channel quality information report is received between the first channel quality information reports.
4. The method according to claim 3 , wherein the first reporting period is different from the second reporting period.
5. The method according to claim 1 , wherein the first content of the second channel quality information report includes a greater number of values/coefficients usable by the receiver for the purpose of frequency domain reconstruction than those included in the second content.
6. The method according to claim 1 , wherein the channel state at the transmitting entity is determined to have changed when the difference between the total energy of one or a plurality of channel quality measures at two time instants is above a threshold.
7. A receiver for receiving a periodic report of channel quality information from a transmitting entity within a communication system, the receiver comprising:
a receiving unit configured to receive a first channel quality information report at a first reporting instance, and to receive a second channel quality information report at a second reporting instance;
wherein a change in a channel state triggers a change in a content of the second channel quality information report between a first content and a second content at the transmitting entity; and
wherein the first content of the second channel quality information report enables a more accurate frequency domain reconstruction of the channel state at the receiver than the second content of the second channel quality information report.
8. The receiver according to claim 7 , wherein the receiving unit is configured to receive the first channel quality information report at a first reporting period and to receive the second channel quality information report at a second reporting period.
9. The receiver according to claim 8 , wherein the receiving unit is configured to receive the second channel quality information report between the first channel quality information reports.
10. The receiver according to claim 9 , wherein the first reporting period is different from the second reporting period.
11. The receiver according to claim 7 , wherein the first content of the second channel quality information report includes a greater number of values/coefficients usable by the receiver for the purpose of frequency domain reconstruction than those included in the second content.
12. The receiver according to claim 7 , wherein the channel state at the transmitting entity is determined to have changed when the difference between the total energy of one or a plurality of channel quality measures at two time instants is above a threshold.