Method for searching for enhanced physical downlink control channel region
The present invention relates to methods for searching an enhanced physical downlink control channel (E-PDCCH), and a device for supporting the methods. According to one embodiment of the present invention, a method for searching an enhanced physical downlink control channel (E-PDCCH) in a wireless access system can comprise the steps of: performing a blind decoding on a control channel region and searching a legacy physical downlink control channel (PDCCH); and searching the E-PDCCH on the basis of the searched legacy PDCCH. In this case, in a subframe to which the E-PDCCH is allocated, using all symbols of the subframe from a first symbol to a third symbol is always preferred for allocation of the legacy PDCCH.
1. A method for searching for an Enhanced Physical Downlink Control Channel (E-PDCCH) in a wireless access system, the method comprising;
searching for a legacy Physical Downlink Control Channel (PDCCH) by blind-decoding a control channel region; and
searching for the E-PDCCH based on the detected legacy PDCCH,
wherein a position of the E-PDCCH is determined as a function of a position of the legacy PDCCH and the E-PDCCH is searched based on the position of the legacy PDCCH without an additional search operation,
wherein if the legacy PDCCH and E-PDCCH are allocated in a subframe, the legacy PDCCH always occupies all of first, second, and third symbols of the subframe,
and
wherein the position of the legacy E-PDCCH is defined by a starting position of the legacy PDCCH, an ending position of the legacy PDCCH and a size of the legacy PDCCH.
2. The method according to claim 1 , wherein a legacy PDCCH signal transmitted on the legacy PDCCH is masked with User Equipment (UE)-specific Cyclic Redundancy Check (CRC).
3. The method according to claim 2 , wherein an E-PDCCH signal transmitted on the E-PDCCH is masked with a common CRC.
4. The method according to claim 2 , wherein an E-PDCCH signal transmitted on the E-PDCCH is masked with the UE-specific CRC.
5. The method according to claim 1 , further comprising acquiring information about an allocated position of the E-PDCCH using information about at least one of a starting position, an ending position, and a size of a region to which the legacy PDCCH is allocated,
wherein the searching for the E-PDCCH comprises searching for the E-PDCCH based on the information about the allocated position of the E-PDCCH and the E-PDCCH is allocated to a data channel region other than the control channel region.
6. The method according to claim 5 , wherein the information about the allocated position of the E-PDCCH, is calculated by a function where is information about a starting position of the legacy PDCCH, is information about an ending position of the legacy PDCCH, and is information about a size of the legacy PDCCH.
7. The method according to claim 1 , the function is defined by the relation between a position and a size of the legacy PDCCH and a position and a size of the E-PDCCH.
8. The method according to claim 1 , the function is defined as the below equation,
l enh =f ( l leg start ,l leg end ,s leg ),
wherein the l enh represents the E-PDCCH, l leg start represents the starting position of the legacy PDCCH, l leg end represents the ending position of the legacy PDCCH and s leg represents the size of the legacy PDCCH.
9. A User Equipment (UE) for searching for an Enhanced Physical Downlink Control Channel (E-PDCCH) in a wireless access system, the UE comprising;
a transmission module;
a reception module; and
a processor configured to control the transmission module and reception module,
wherein the processor is further configured to:
search for a legacy Physical Downlink Control Channel (PDCCH) by blind-decoding a control channel region, and
search for the E-PDCCH based on the detected legacy PDCCH,
wherein a position of the E-PDCCH is determined as a function of a position of the legacy PDCCH and the E-PDCCH is searched based on the position of the legacy PDCCH without an additional search operation,
wherein if the legacy PDCCH and E-PDCCH are allocated in a subframe, the legacy PDCCH always occupies all of first, second, and third symbols of the subframe,
and
wherein the position of the legacy E-PDCCH is defined by a starting position of the legacy PDCCH, an ending position of the legacy PDCCH and a size of the legacy PDCCH.
10. The UE according to claim 9 , wherein a legacy PDCCH signal transmitted on the legacy PDCCH is masked with UE-specific Cyclic Redundancy Check (CRC).
11. The UE according to claim 10 , wherein an E-PDCCH signal transmitted on the E-PDCCH is masked with a common CRC.
12. The UE according to claim 10 , wherein an E-PDCCH signal transmitted on the E-PDCCH is masked with the UE-specific CRC.
13. The UE according to claim 9 , wherein the processor acquires information about an allocated position of the E-PDCCH using information about at least one of a starting position, an ending position, and a size of a region to which the legacy PDCCH is allocated,
wherein the processor searches for the E-PDCCH based on the information about the allocated position of the E-PDCCH and the E-PDCCH is allocated to a data channel region other than the control channel region.
14. The UE according to claim 13 , wherein the information about the allocated position of the E-PDCCH, is calculated by a function where is information about a starting position of the legacy PDCCH, is information about an ending position of the legacy PDCCH, and is information about a size of the legacy PDCCH.