Apparatus and method for feeding back channel quality information and scheduling apparatus and method using the same in a wireless communication system
An apparatus and method are provided for feeding back channel quality information and performing scheduling using the fed-back channel quality information in a wireless communication system based on Orthogonal Frequency Division Multiple Access (OFDMA). In the OFDMA wireless communication system, forward performance degradation due to a decrease in an amount of reverse channel quality information is reduced, and also an increase in the reverse load due to channel quality information feedback is suppressed. A base station controls power of a physical channel using information fed back from a mobile station. In a method for feeding back channel quality information from the mobile station, sub-band-by-sub-band channel quality information is measured and channel-by-channel quality information of a number of channels is transmitted in order of sub-bands of better channel quality information. Average channel quality information for a total band is measured and transmitted.
1. A method for feeding back channel quality information (CQI), at a mobile station, in a wireless communication system based on Orthogonal Frequency Division Multiple Access (OFDMA), the method comprising:
calculating, at the mobile station, a wideband CQI for an entire band, the entire band including at least two sub-bands;
calculating, at the mobile station, at least one sub-band CQI for the at least one sub-band;
transmitting, at the mobile station, the at least one sub-band CQI for the at least one sub-band at a transmission time interval for a sub-band CQI transmission; and
transmitting, at the mobile station, the wideband CQI at a transmission time interval for a wideband CQI,
wherein the transmission time interval for a wideband CQI is set based on N times of number of the transmission time interval for a sub-band CQI transmission, and
wherein N is an integer greater than 1.
2. The method of claim 1 , wherein the N is configured by a base station.
3. The method of claim 1 , wherein a number of sub-bands are configured by a base station.
4. The method of claim 1 , wherein the at least one sub-band for the sub-band CQI transmission is configured by a base station.
5. The method of claim 1 , wherein the at least one sub-band for the sub-band CQI transmission is selected by the mobile station.
6. The method of claim 4 , wherein when the at least one sub-band for the sub-band CQI transmission is configured by the base station, the at least one sub-band CQI for the at least one sub-hand does not include at least one index indicating a position of the at least one sub-band but at least one CQI value.
7. The method of claim 5 , wherein when the at least one sub-band for the sub-band CQI transmission is selected by the mobile station, the at least one sub-band CQI for the at least one sub-band comprises at least one CQI value and at least one index indicating a position of the at least one sub-band.
8. The method of claim 1 , further comprising:
performing a channel encoding process for the wideband CQI for the entire band and the at least one sub-band CQI for the at least one sub-band before transmitting the at least one sub-band CQI for the at least one sub-band and transmitting the wideband CQI;
modulating the encoded wideband CQI for the entire band and the at least one sub-band CQI for the at least one sub-band based on a set modulation scheme; and
performing physical channel configuration to insert the modulated wideband CQI for the entire band and the at least one sub-band CQI for the at least one sub-band into a physical channel allocated in a reverse direction in the wireless communication system based on OFDMA.
9. The method of claim 1 ,
wherein the wideband CQI for the entire band and the at least one sub-band CQI for the at least one sub-band are transmitted during the same transmission time interval.
10. The method of claim 9 , wherein the at least one sub-band CQI for the at least one sub-band comprises at least one CQI value and at least one index indicating a position of the at least one sub-band.
11. An apparatus for feeding back channel quality information (CQI), at a mobile station, in a wireless communication system based on Orthogonal Frequency Division Multiple Access (OFDMA), the method comprising:
a controller configured to:
calculate a wideband CQI for an entire band, the entire band including at least two sub-bands, and
calculate at least one sub-band CQI for the at least one sub-band; and a transmitter configured to:
transmit at the at least one sub-band CQI for the at least one sub-band at a transmission time interval for a sub-band CQI transmission and the wideband CQI at a transmission time interval for a wideband CQI transmission,
wherein the transmission time interval for a wideband CQI is set based on N times of a number of the transmission time interval for a sub-band CQI transmission, and
wherein N is an integer greater than 1.
12. The apparatus of claim 11 , wherein the N is configured by a base station.
13. The apparatus of claim 11 , wherein a number of sub-bands are configured by a base station.
14. The apparatus of claim 11 , wherein the at least one sub-band for the sub-band CQI transmission is configured by a base station.
15. The apparatus of claim 11 , wherein the at least one sub-band for the sub-band CQI transmission is selected by the mobile station.
16. The apparatus of claim 14 , wherein when the at least one sub-band for the sub-band CQI transmission is configured by the base station, the at least one sub-band CQI for the at least one sub-band does not include at least one index indicating a position of the at least one sub-band but at least one CQI value.
17. The apparatus of claim 15 , wherein when the at least one sub-band for the sub-band CQI transmission is selected by the mobile station, the at least one sub-band CQI for the at least one sub-band comprises at least one CQI value and at least one index indicating a position of the at least one sub-band.
18. The apparatus of claim 11 , further comprising:
a channel encoder configured to perform channel encoding for the wideband CQI for the entire band and the at least one sub-band CQI for the at least one sub-band before transmitting at least one sub-band CQI for the at least one sub-band and transmitting the wideband CQI;
a modulator configured to modulate the encoded wideband CQI for the entire band and the at least one sub-band CQI for the at least one sub-band based on a set modulation scheme; and
a physical channel configurator configured to insert the modulated wideband CQI for the entire band and the at least one sub-band CQI for the at least one sub-band into a physical channel allocated in a reverse direction in the wireless communication system based on OFDMA.
19. The apparatus of claim 11 ,
wherein the transmitter transmits the wideband CQI for the entire band and the at least one sub-band CQI for the at least one sub-band during the same transmission time interval.
20. The apparatus of claim 19 , wherein the at least one sub-band CQI for the at least one sub-band comprises at least one CQI value and at least one index indicating a position of the at least one sub-band.
21. A method for receiving, at a base station, channel quality information (CQI) transmitted from a mobile station in a wireless communication system based on Orthogonal Frequency Division Multiple Access (OFDMA), the method comprising:
receiving, at the base station, at least one sub-band CQI for at least one sub-band at a transmission time interval for a sub-band CQI transmission;
receiving, at the base station, a wideband CQI for an entire band at a transmission time interval for a wideband CQI transmission,
the entire band including at least two sub-bands,
wherein the transmission time interval for a wideband CQI is set based on N times of a number of the transmission time interval for a sub-band CQI transmission, and
wherein N is an integer greater than 1.
22. method of claim 21 , wherein the N is configured by the base station.
23. The method of claim 21 , wherein a number of sub-bands are configured by the base station.
24. The method of claim 21 , wherein the at least one sub-band for the sub-band CQI transmission is configured by the base station.
25. The method of claim 21 , wherein the at least one sub-band for the sub-band CQI transmission is selected by the mobile station.
26. The method of claim 24 , wherein when the at least one sub-band for the sub-band CQI transmission is configured by the base station, the at least one sub-band CQI for the at least one sub-band does not include at least one index indicating a position of the at least one sub-band but at least one CQI value.
27. The method of claim 25 , wherein when the at least one sub-band for the sub-band CQI transmission is selected by the mobile station, the at least one sub-band CQI for the at least one sub-band comprises at least one CQI value and at least one index indicating a position of the at least one sub-band.
28. The method of claim 21 ,
wherein the wideband CQI is for an entire band, and
wherein the wideband CQI for the entire band and the at least one sub-band CQI for the at least one sub-band are received during the same transmission time interval.
29. The method of claim 28 , wherein the at least one sub-band CQI for the at least one sub-band comprises at least one CQI value and at least one index indicating a position of the at least one sub-band.
30. An apparatus for receiving, at a base station, channel quality information (CQI) transmitted from a mobile station in a wireless communication system based on Orthogonal Frequency Division Multiple Access (OFDMA), the apparatus comprising:
a receiver configured to:
receive, at the base station, at least one sub-band CQI for at least one sub-band at a transmission time interval for a sub-band CQI transmission and a wideband CQI for an entire band at a transmission time interval for a wideband CQI transmission, the entire band including at least two sub-bands; and
a controller,
wherein the transmission time interval for the wideband CQI is set based on N times of a number of the transmission time interval for the at least one sub-band CQI transmission, and
wherein N is an integer greater than 1.
31. the apparatus of claim 30 , wherein the N is configured by the base station.
32. The apparatus of claim 30 , wherein a number of sub-bands are configured by the base station.
33. The apparatus of claim 30 , wherein the at least one sub-band for the sub-band CQI transmission is configured by the base station.
34. The apparatus of claim 30 , wherein the at least one sub-band for the sub-band CQI transmission is selected by the mobile station.
35. The apparatus of claim 33 , wherein when the at least one sub-band for the sub-band CQI transmission is configured by the base station, the at least one sub-band CQI for the at least one sub-band does not include at least one index indicating a position of the at least one sub-band but at least one CQI value.
36. The apparatus of claim 34 , wherein when the at least one sub-band for the sub-band CQI transmission is selected by the mobile station, the at least one sub-band CQI for the at least one sub-band comprises at least one CQI value and at least one index indicating a position of the at least one sub-band.
37. The apparatus of claim 30 , wherein the transmission time interval for the wideband CQI for the entire band and the transmission time interval for the at least one sub-band CQI for the at least one sub-band is the same transmission time interval.
38. The apparatus of claim 37 , wherein the at least one sub-band CQI for the at least one sub-band comprises at least one CQI value and at least one index indicating a position of the at least one sub-band.