Method and apparatus for transmitting and receiving data in a wireless communication system

1. A method for transmitting and receiving data in a wireless communication system supporting multiple carriers, performed by a wireless device, the method comprising:

determining a starting OFDM symbol of a physical downlink shared channel (PDSCH) which is variably located by the presence of a reference signal (RS);

determining a number of physical resource blocks (PRBs) used for an enhanced physical downlink control channel (ePDCCH); and

determining the ePDCCH;

wherein the ePDCCH is set by one or more sets of PRBs within the PDSCH configured for a User Equipment (UE) to monitor the ePDCCH.

2. The method of claim 1 , wherein determining the number of PRBs further comprises determining:

a number of PRBs used for the ePDCCH which is allocated with PDSCH PRBs of a resource allocation by Downlink Control Information (DCI),

a number of PRBs overlapped between the PDSCH PRBs and the ePDCCH PRBs by the DCI, or

a number of PRBs between the PDSCH PRBs and the ePDCCH PRBs are localized or distributed.

3. The method of claim 2 , further comprising:

determining one or more sets of ePDCCHs by indicating validation/activation of the DCI via a physical downlink control channel (PDCCH) or the ePDCCH, or determining the one or more sets of ePDCCHs by signaling from a higher-layer signal.

4. The method of claim 2 , wherein determining the number of PRBs further comprises:

determining whether at least one of a scheduling DCI or PDSCH is transmitted from different transmission points,

determining whether a PDSCH is rate matched or not rate matched according to the scheduling DCI, and

determining an ePDCCH sets using a PQI (PDSCH RE mapping and Qausi-co-located Indicator) index associated with the ePDCCH sets, or a linked CRS or discovery signal in each of the PQI.

5. The method of claim 1 , wherein determining the ePDCCH further comprises:

determining one or more sets of ePDCCHs by a PQI (PDSCH RE mapping and Qausi-collocated Indicator) index.

6. The method of claim 5 , wherein the PQI is indicated by a PQI field in a DCI format 2D or the PQI is indicated by a RRC signal configured for DCI format 1A.

7. The method of claim 5 , wherein determining the ePDCCH further comprises:

determining the one or more sets of ePDCCHs by a Cell specific RS (CRS), wherein the CRS includes a channel state information (CSI) RS assigned with a linked cell identification (ID) of transmission point.

8. The method of claim 1 , wherein the starting OFDM symbol of the PDSCH is variably set at the 0th OFDM symbol or the 3rd OFDM symbol by the presence of a Cell specific RS (CRS).

9. The method of claim 1 , wherein determining the ePDCCH further comprises:

determining one or more sets of ePDCCHs which are indicated with different DCI formats according to a transmission mode of the UE.

10. The method of claim 1 , determining the ePDCCH further comprises:

determining the one or more sets of ePDCCHs by assuming that a tracking RS, a Demodulation reference signal (DM-RS), and a CSI-RS are Quasi-collocated (QCL).

11. A wireless device for transmitting and receiving data in a wireless communication system supporting multiple carriers, comprising:

a radio frequency unit that receives a radio signal; and

a processor, operatively coupled with the radio frequency unit, that:

determines a starting OFDM symbol of a physical downlink shared channel (PDSCH) which is variably located by the presence of a reference signal (RS),

determines a number of physical resource blocks (PRBs) used for an enhanced physical downlink control channel (ePDCCH), and

determines the ePDCCH,

wherein the ePDCCH is set by one or more set of PRBs within the PDSCH configured for a User Equipment (UE) to monitor the ePDCCH.

12. The wireless device of claim 11 , wherein the processor further determines:

a number of PRBs used for the ePDCCH which is allocated with PDSCH PRBs of a resource allocation by a Downlink Control Information (DCI),

a number of PRBs overlapped between the PDSCH PRBs and the ePDCCH PRBs by the DCI, or

a number of PRBs between the PDSCH PRBs and the ePDCCH PRBs are localized or distributed.

13. The wireless device of claim 11 , wherein the processor further: determines one or more sets of ePDCCHs by indicating validation/activation of the DCI via a physical downlink control channel (PDCCH) or the ePDCCH, or by signaling from a higher-layer signal as a Semi-persistent Scheduling (SPS).

14. The wireless device of claim 11 , wherein the processor is configured to: determine one or more sets of ePDCCHs by a PQI (PDSCH RE mapping and Qausi-collocated Indicator) index, wherein the PQI is indicated by a PQI field in a DCI format 2D or the PQI is indicated by a RRC signal configured for DCI format 1A.

15. The wireless device of claim 11 , wherein the processor further: determines one or more sets of ePDCCHs by a Cell specific RS (CRS), wherein the CRS includes a channel state information (CSI) RS assigned with a linked cell identification (ID) of transmission point, and the starting OFDM symbol of the PDSCH is variably set at the 0th OFDM symbol or the 3rd OFDM symbol by the presence of the CRS.

16. The wireless device of claim 11 , wherein the processor further: determines one or more sets of ePDCCHs which is indicated with different DCI formats according to a transmission mode of the UE.

17. A method for transmitting and receiving data in a wireless communication system supporting multiple carriers, performed by a wireless device, the method comprising:

receiving a signal including a common search space (CSS) and UE specific search space (USS) for an enhanced physical downlink control channel (ePDCCH),

determining cyclic prefix(CP) lengths for the CSS and the USS for the ePDCCH respectively, and

determining the ePDCCH using the determined CP lengths,

wherein a UE is configured with the same CP length for a commonly used CSS and USS for the ePDCCH or the UE is configured with separate CP lengths for a separately used CSS and USS for the ePDCCH.