Method for transmitting or receiving PDCCH and user equipment or base station for the method

1. A method for receiving an enhanced physical downlink control channel (E-PDCCH) in a data region of a downlink subframe by a user equipment (UE) in a wireless communication system, the method comprising the step of:

detecting the E-PDCCH by performing blind decoding of a plurality of E-PDCCH candidates included in a search space for the E-PDCCH,

wherein the blind decoding is performed in accordance with an order of priority given to each of a plurality of sub-search spaces constituting the search space, and

wherein the order of priority is determined based on downlink transmission information including at least one of a transmission data rate of a physical downlink shared channel (PDSCH) indicated by the E-PDCCH, a payload size of the PDSCH, a transmission modulation order of the PDSCH, and the number of resource blocks allocated to the PDSCH.

2. The method according to claim 1 , further comprising the step of starting demodulation for a physical downlink shared channel (PDSCH) designated by the E-PDCCH, if the result of the blinding decoding is successful.

3. The method according to claim 1 , further comprising the step of performing blind decoding for the sub-search space with low priority, if the result of the blind decoding for the sub-search space with high priority is not successful.

4. The method according to claim 1 , wherein the E-PDCCH corresponding to the PDSCH with higher or larger transmission data rate, transmission modulation order, payload size or number of resource blocks is allocated to a sub-search space having a higher order of priority.

5. A user equipment configured to receive an enhanced physical downlink control channel (E-PDCCH) in a data region of a downlink subframe in a wireless communication system, the user equipment comprising:

a radio frequency (RF) unit; and

a processor,

wherein the processor is configured to detect the E-PDCCH by performing blind decoding of a plurality of E-PDCCH candidates included in a search space for the E-PDCCH, and the blind decoding is performed in accordance with an order of priority given to each of a plurality of sub-search spaces constituting the search space, and

wherein the order of priority is determined based on downlink transmission information including at least one of a transmission data rate of a physical downlink shared channel (PDSCH) indicated by the E-PDCCH, a payload size of the PDSCH, a transmission modulation scheme of the PDSCH, and the number of resource blocks allocated to the PDSCH.

6. The user equipment according to claim 5 , wherein the processor is configured to start demodulation for a physical downlink shared channel (PDSCH) designated by the E-PDCCH, if the result of the blinding decoding is successful.

7. The user equipment according to claim 5 , wherein the processor is configured to perform blind decoding for the sub-search space with low priority, if the result of the blind decoding for the sub-search space with high priority is not successful.

8. The user equipment according to claim 5 , wherein the E-PDCCH corresponding to the PDSCH with higher or larger transmission data rate, transmission modulation order, payload size or number of resource blocks is allocated to a sub-search space having a higher order of priority.

9. A method for transmitting an enhanced physical downlink control channel (E-PDCCH) in a data region of a downlink subframe from a base station to a user equipment (UE) in a wireless communication system, the method comprising the steps of:

dividing a search space for the E-PDCCH including a plurality of E-PDCCH candidates into a plurality of sub-search spaces;

giving an order of priority to each of the plurality of sub-search spaces; and

transmitting the E-PDCCH to the user equipment through the sub-search spaces on the basis of the given order of priority,

wherein the order of priority is determined based on downlink transmission information including at least one of a transmission data rate of a physical downlink shared channel (PDSCH) indicated by the E-PDCCH, a payload size of the PDSCH, a transmission modulation scheme of the PDSCH, and the number of resource blocks allocated to the PDSCH.

10. The method according to claim 9 , wherein the E-PDCCH corresponding to the PDSCH with higher or larger transmission data rate, transmission modulation order, payload size or number of resource blocks is allocated to a sub-search space having a higher order of priority.

11. A base station configured to transmit an enhanced physical downlink control channel (E-PDCCH) to a user equipment in a data region of downlink subframe in a wireless communication system, the base station comprising:

a processor,

wherein the processor is configured to

divide a search space for the E-PDCCH including a plurality of E-PDCCH candidates included in the downlink subframe into a plurality of sub-search spaces,

give an order of priority to each of the plurality of sub-search spaces, and

transmit the E-PDCCH to the user equipment through the sub-search spaces on the basis of the given order of priority, and

wherein the order of priority is determined based on downlink transmission information including at least one of a transmission data rate of a physical downlink shared channel (PDSCH) indicated by the E-PDCCH, a payload size of the PDSCH, a transmission modulation scheme of the PDSCH, and the number of resource blocks allocated to the PDSCH.

12. The base station according to claim 11 , wherein the E-PDCCH corresponding to the PDSCH with higher or larger transmission data rate, transmission modulation order, payload size or number of resource blocks is allocated to a sub-search space having a higher order of priority.