Method for transmitting downlink control channel in a mobile communications system and a method for mapping the control channel to physical resource using block interleaver in a mobile communications system
A method for transmitting a downlink control channel in a mobile communication system and a method for mapping the control channel to physical resources using a block interleaver are provided. In order to transmit a downlink control channel in a mobile communication system, information bits are modulated to generate one or more modulation symbols according to a specific modulation scheme, the modulation symbols are interleaved using a block interleaver, and the interleaved modulated symbols are mapped to resource elements allocated for transmission of at least one control channel in a subframe, thereby transmitting the at least one control channel.
1. A method for receiving a control channel in a mobile communication system, the method comprising:
receiving, by a user equipment (UE), at least one PDCCH,
wherein the at least one PDCCH is configured by interleaving a plurality of modulation symbol groups using a block interleaver, wherein each of the plurality of modulation symbol groups includes at least one modulation symbol,
wherein the interleaving is performed by inputting the plurality of modulation symbol groups row by row to the block interleaver, performing inter-column permutation for the inputted plurality of modulation symbol groups, and outputting the permutated plurality of modulation symbol groups column by column from the block interleaver, and
wherein the outputted plurality of modulation symbol groups are cyclically shifted using a cell identifier.
2. The method of claim 1 , wherein a size of the block interleaver is determined according to a number of the plurality of modulation symbol groups transmitted in the subframe.
3. The method of claim 2 , wherein a number of rows of the block interleaver is determined based on a predetermined number of columns of the block interleaver and the number of the plurality of modulation symbol groups transmitted in the subframe.
4. The method of claim 1 , wherein each of the plurality of modulation symbol groups is mapped to a plurality of resource elements allocated for signals excluding at least one of a reference signal, a Physical control format indicator channel (PHICH) signal, and a Physical control format indicator channel (PCFICH) signal.
5. The method of claim 1 , wherein each of the plurality of modulation symbol groups is mapped according to a time-first mapping scheme.
6. The method of claim 1 , wherein the PDCCH is transmitted using one or more continuous Control Channel Elements (CCEs), wherein each of the Control Channel Elements includes at least one of the plurality of modulation symbols.
7. A apparatus for receiving a control channel in a mobile communication system, the apparatus comprising:
a receiver configured to receive at least one PDCCH,
wherein the at least one PDCCH is configured by interleaving a plurality of modulation symbol groups using a block interleaver, wherein each of the plurality of modulation symbol groups includes at least one modulation symbol,
wherein the interleaving is performed by inputting the plurality of modulation symbol groups row by row to the block interleaver, performing inter-column permutation for the inputted plurality of modulation symbol groups, and outputting the permutated plurality of modulation symbol groups column by column from the block interleaver, and
wherein the plurality of modulation symbol groups are cyclically shifted using a cell identifier.
8. The apparatus of claim 7 , wherein a size of the block interleaver is determined according to a number of the plurality of modulation symbol groups transmitted in the subframe.
9. The apparatus of claim 8 , wherein a number of rows of the block interleaver is determined based on a predetermined number of columns of the block interleaver and the number of the plurality of modulation symbol groups transmitted in the subframe.
10. The apparatus of claim 7 , wherein each of the plurality of modulation symbol groups is mapped to a plurality of resource elements allocated for signals excluding at least one of a reference signal, a Physical control format indicator channel (PHICH) signal, and a Physical control format indicator channel (PCFICH) signal.
11. The apparatus of claim 7 , wherein each of the plurality of modulation symbol groups is mapped according to a time-first mapping scheme.
12. The apparatus of claim 7 , wherein the PDCCH is transmitted using one or more continuous Control Channel Elements (CCEs), wherein each of the Control Channel Elements includes at least one of the plurality of modulation symbols.