Method for allocating resources for downlink control channel in wireless communication system and device for same
A method for allocating resources for a downlink control channel by a base station in a wireless communication system is disclosed. Specifically, the method comprises the steps of: mapping resource elements to resource element groups for each of resource blocks; forming control channel elements by using a predetermined number of resource element groups from among the resource element groups; and allocating control channel elements of a number corresponding to an aggregation level of the downlink control channel as resources for the downlink control channel, wherein the number of available resource elements included in each of the resource element groups or the number of available resource elements included in each of the control channel elements of a number corresponding to the aggregation level is uniform.
1. A method for allocating a resource for a downlink control channel by a base station (BS) in a wireless communication system, the method comprising:
mapping resource elements for a channel state information reference signal (CSI-RS) transmission in each resource block for the downlink control channel into a first predetermined number of resource element groups equally;
mapping remaining resource elements other than the resource elements for the CSI-RS transmission into the first predetermined number of resource element groups by dividing the remaining resource elements in each resource block for the downlink control channel along a frequency domain;
configuring each control channel element using a second predetermined number of resource element groups among the first predetermined number of resource element groups;
allocating the control channel elements as the resource for the downlink control channel, wherein the number of control channel elements equals an aggregation level of the downlink control channel, and
transmitting the downlink control channel using the allocated resource,
wherein the number of available resource elements included in each resource element group is equivalent.
2. The method according to claim 1 , wherein the number of resource elements in each resource element group, to which one or more reference signals, including the CSI-RS are allocated, is changed according to a type of subframe in which the downlink control channel is transmitted, and
wherein the number of resource elements to which the one or more reference signals, including the CSI-RS, are allocated in each resource element group is equivalent.
3. The method according to claim 1 , wherein the number of resource elements in each resource element group, to which one or more reference signals including the CSI-RS are allocated, is changed based on the configuration of the one or more reference signals configured for each of the resource blocks, and
wherein the number of resource elements to which the one or more reference signals, including the CSI-RS, are allocated in each resource element group is equivalent.
4. The method according to claim 1 , wherein each of the control channel elements, of which the number is the same as the aggregation level, is included in a different resource block.
5. The method according to claim 1 , wherein the second predetermined number is determined according to a type of a subframe in which the downlink control channel is transmitted.
6. The method according to claim 1 , further comprising puncturing a resource element, to which one or more reference signals, including the CSI-RS, are allocated for the downlink control channel.
7. The method according to claim 1 , further comprising rate-matching the downlink control channel so as to correspond to resources for the downlink control channel, obtained by excluding a resource element for one or more reference signals including the CSI-RS.
8. The method according to claim 1 , wherein the first predetermined number is 4.
9. The method according to claim 1 , wherein 16 resource elements are allocated for a user equipment specific reference signal, wherein the 16 resource elements are allocated in symbols #5, #6, #12, #13 among symbols #0 to #13 of each resource block for the downlink control channel, in subcarriers #0, #5, #6, #11 among subcarriers #0 to #11 of each resource block for the downlink control channel.
10. The method according to claim 1 , wherein the available resource elements are resource elements to which one or more reference signals including the CSI-RS are not allocated and resource elements not used for legacy physical downlink control channel transmission.
11. The method according to claim 1 , wherein each resource block for the downlink control channel is a pre-configured search space of the downlink control channel.