Method of user equipment monitoring control information in a multiple node system and user equipment using the method

1. A method for monitoring control information in a wireless communication system, the method comprising:

receiving, by a User Equipment (UE), information about a first reference position for a first Enhanced-Physical Control Format Indication Channel (E-PCFICH) from a Base Station (BS),

wherein the information about the first reference position for the first E-PCFICH indicates a Resource Block (RB) where a first E-PCFICH region is started;

detecting, by the UE, the first E-PCFICH in the RB indicated by the information about the first reference position for the first E-PCFICH;

obtaining, by the UE, information about a second reference position for a second E-PCFICH based on the information about the first reference position,

wherein the information about the second reference position for the second E-PCFICH indicates an RB where a second E-PCFICH region is started, and

wherein each of the first E-PCFICH and the second E-PCFICH is a control channel comprising information about a size of a frequency domain for an Enhanced-Physical Downlink Control Channel (E-PDCCH) for demodulating control information by using a UE-specific Reference Signal (URS);

detecting, by the UE, the second E-PCFICH in the RB indicated by the information about the second reference position for the second E-PCFICH; and

receiving information related to a total number of a plurality of E-PCFICHs when the plurality of E-PCFICHs is multiplexed within one RB,

wherein the information related to the total number of the plurality of E-PCFICHs is signaled when the plurality of E-PCFICHs is multiplexed within the one RB,

wherein, when the received information indicates that one E-PCFICH is positioned within one of the E-PCFICH regions, all of three resource element groups (REGs) are allocated to the one E-PCFICH,

wherein, when the received information indicates that two E-PCFICHs are positioned within one of the E-PCFICH regions, a first, a third, a fifth number of REGs are allocated to a first number of E-PCFICHs, and a second, a fourth, a sixth number of REGs are allocated to a second number of E-PCFICHs, and

wherein, when the received information indicates that three E-PCFICHs are positioned within the E-PCFICH regions, a first, a fourth, a seventh number of REGs are allocated to a first number of E-PCFICHs, and a second, a fifth, an eighth number of REGs are allocated to a second number of E-PCFICHs, and a third, a sixth, an ninth number of REGs are allocated to a third number of E-PCFICHs.

2. The method of claim 1 , further comprising:

obtaining a frequency size of the first E-PDCCH region through the first E-PCFICH and obtaining a frequency size of the second E-PDCCH region through the second E-PCFICH; and

searching the first E-PDCCH region and the second E-PDCCH region for the E-PDCCH for the UE.

3. The method of claim 2 , further comprising:

receiving information about a third reference position for the first E-PDCCH indicating the RB where the first E-PDCCH region is started.

4. The method of claim 3 , wherein the information about the third reference position for the first E-PDCCH is further used to determine the RB where the second E-PDCCH region is started.

5. The method of claim 1 , wherein the information about the first reference position is received through a higher layer signal.

6. A User Equipment (UE) for monitoring control information in a wireless communication system, the UE comprising:

a Radio Frequency (RF) unit configured to transmit and receive radio signals; and

a processor connected to the RF unit, the processor being configured to:

receive information about a first reference position for a first Enhanced-Physical Control Format Indication Channel (E-PCFICH) from a Base Station (BS),

wherein the information about the first reference position for the first E-PCFICH indicates a Resource Block (RB) where a first E-PCFICH region is started,

detect the first E-PCFICH in the RB indicated by the information about the first reference position for the first E-PCFICH,

obtain information about a second reference position for a second E-PCFICH based on the information about the first reference position,

wherein the information about the second reference position for the second E-PCFICH indicates an RB where a second E-PCFICH region is started, and

wherein each of the first E-PCFICH and the second E-PCFICH is a control channel comprising information about a size of a frequency domain for an Enhanced-Physical Downlink Control Channel (E-PDCCH) for demodulating the control information by using a UE-specific Reference Signal (URS),

detect the second E-PCFICH in the RB indicated by the information about the second reference position for the second E-PCFICH, and

receive information related to a total number of a plurality of E-PCFICHs when the plurality of E-PCFICHs is multiplexed within one RB,

wherein the information related to the total number of the plurality of E-PCFICHs is signaled when the plurality of E-PCFICHs is multiplexed within the one RB,

wherein, when the received information indicates that one E-PCFICH is positioned within one of the E-PCFICH regions, all of three resource element groups (REGs) are allocated to the one E-PCFICH,

wherein, when the received information indicates that two E-PCFICHs are positioned within one of the E-PCFICH regions, a first, a third, a fifth number of REGs are allocated to a first number of E-PCFICHs, and a second, a fourth, a sixth number of REGs are allocated to a second number of E-PCFICHs, and

wherein, when the received information indicates that three E-PCFICHs are positioned within one of the E-PCFICH regions, a first, a fourth, a seventh number of REGs are allocated to a first number of E-PCFICHs, and a second, a fifth, an eighth number of REGs are allocated to a second number of E-PCFICHs, and a third, a sixth, an ninth number of REGs are allocated to a third number of E-PCFICHs.

7. The user equipment of claim 6 , wherein the processor is further configured to:

obtain a frequency size of the first E-PDCCH region through the first E-PCFICH, and obtain a frequency size of the second E-PDCCH region through the second E-PCFICH, and

search the first E-PDCCH region and the second E-PDCCH region for the E-PDCCH for the user equipment.

8. The user equipment of claim 7 , wherein the processor is further configured to receive information about a third reference position for the first E-PDCCH indicating the RB where the first E-PDCCH region is started.

9. The user equipment of claim 8 , wherein the information about the third reference position for the first E-PDCCH is further used to determine the RB where the second E-PDCCH region is started.

10. The user equipment of claim 6 , wherein the information about the first reference position is received through a higher layer signal.