Method for transmitting and receiving downlink reference signals in a wireless communication system having multiple antennas

A method for transmitting downlink Reference Signals (RSs) in a base station in a multi-antenna wireless communication system, the method comprising:

• transmitting a first Orthogonal Frequency Division Multiplexing (OFDM) symbol in which demodulation RSs for a plurality of antenna port of first group are allocated in a predetermined order along a frequency axis;
• and
• transmitting a second OFDM symbol in which demodulation RSs for a plurality of antenna port of second group are allocated in Code Division Multiplexing (CDM).

A method for transmitting downlink Reference Signals (RSs) in a base station in a multi-antenna wireless communication system, the method comprising:

• transmitting a primary subframe including a first Orthogonal Frequency Division Multiplexing (OFDM) symbol in which common RSs for a plurality of antenna port of first group are allocated in a predetermined order along a frequency axis, and a second OFDM symbol in which demodulation-dedicated RSs for a plurality of antenna port of second group are multiplexed in Code Division Multiplexing (CDM);
• and
• transmitting a secondary subframe including a third OFDM symbol in which common RSs for the plurality of antenna port of second group are allocated in a predetermined order along the frequency axis, and a fourth OFDM symbol in which demodulation-dedicated RSs for the plurality of antenna port of group are multiplexed in CDM.

A method for transmitting downlink Reference Signals (RSs) in a base station in a multi-antenna wireless communication system, the method comprising:

• transmitting a primary subframe including a first Orthogonal Frequency Division Multiplexing (OFDM) symbol in which common RSs for a plurality of antenna port of first group are allocated in a predetermined order along a frequency axis, and a second OFDM symbol in which demodulation-dedicated RSs for a plurality of antenna port of second group are multiplexed in Frequency Division Multiplexing (FDM);
• and
• transmitting a secondary subframe including a third OFDM symbol in which common RSs for the plurality of antenna port of second group are allocated in a predetermined order along the frequency axis, and a fourth OFDM symbol in which demodulation-dedicated RSs for the plurality of antenna port of first group are multiplexed in FDM.

A method for receiving downlink Reference Signals (RSs) in a user equipment in a multi-antenna wireless communication system, the method comprising:

• receiving a first Orthogonal Frequency Division Multiplexing (OFDM) symbol in which RSs for a plurality of antenna port of first group are allocated in a predetermined order along a frequency axis, RSs for a plurality of antenna port of second group are allocated in a predetermined order along the frequency axis, and the RSs for the plurality of antenna port of first group are multiplexed in Code Division Multiplexing (CDM) with the RSs for the plurality of antenna port of second group by pairing each of the plurality of antenna port of first group with one of the plurality of antenna port of second group;
• and
• receiving a second OFDM symbol in which the RSs for the plurality of antenna port of first group and the RSs for the plurality of antenna of second group are positioned in an RS pattern being a frequency-domain shift of an RS pattern of the first OFDM symbol.

A method for receiving downlink Reference Signals (RSs) in a user equipment in a multi-antenna wireless communication system, the method comprising:

• receiving a first OFDM symbol in which demodulation-dedicated RSs for a plurality of antenna port of first group are allocated in Code Division Multiplexing (CDM);
• and
• receiving a second OFDM symbol in which demodulation-dedicated RSs for a plurality of antenna port of second group are multiplexed in CDM.