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 transmitting a physical downlink control channel (PDCCH) in a mobile communication system, the method comprising:
inputting one or more modulation symbol groups row by row to a block interleaver;
performing inter-column permutation for the inputted one or more modulation symbol groups;
outputting the permuted modulation symbol groups column by column from the block interleaver:
mapping the outputted modulation symbol groups to resource elements allocated for transmitting at least one PDCCH in a subframe; and
transmitting the at least one PDCCH,
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. A apparatus for transmitting a physical downlink control channel (PDCCH) in a mobile communication system, the apparatus comprising:
a block interleaver; and
one or more transmission antennas;
wherein the apparatus is configured to:
input one or more modulation symbol groups row by row to the block interleaver;
perform inter-column permutation for the inputted one or more modulation symbol groups by using the block interleaver;
output the permuted modulation symbol groups column by column from the block interleaver;
map the outputted modulation symbol groups to resource elements allocated for transmitting at least one PDCCH in a subframe; and
transmit the at least one PDCCH by using the one or more transmission antennas, and
wherein the outputted plurality of modulation symbol groups are cyclically shifted using a cell identifier.
5. The apparatus of claim 4 , wherein a size of the block interleaver is determined according to a number of the plurality of modulation symbol groups transmitted in the subframe.
6. The apparatus of claim 5 , 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.