Method and apparatus for channel estimation for radio link between a base station and a relay station

A method for performing downlink transmission at a downlink transmission entity in a wireless communication system, the method comprising:

• transmitting, in a first resource block (RB) pair within an RB bundle, downlink control information through a Physical Downlink Control Channel (PDCCH) and a first Demodulation Reference Signal (DMRS) used for estimating a downlink channel to demodulate the PDCCH;
• and
• transmitting, in one or more second RB pairs within the RB bundle, downlink data through a Physical Downlink Shared Channel (PDSCH) and a second DMRS used for estimating a downlink channel to demodulate the PDSCH,
• wherein the downlink channel estimated by using the second DMRS is estimated based on an assumption that a same precoder is applied to the one or more second RB pairs.

A downlink reception entity for performing downlink reception, the downlink reception entity comprising:

• a reception module configured to receive a downlink signal from a downlink transmission entity;
• a transmission module configured to transmit an uplink signal to the downlink transmission entity;
• and
• a processor configured to control the reception module and the transmission module,
• wherein the processor is further configured to:
• receive, through the reception module, downlink control information by demodulating a Physical Downlink Control Channel (PDCCH) in a first resource block (RB) pair within an RB bundle based on a downlink channel estimated by using a first Demodulation Reference Signal (DMRS) in the first RB pair;
• and
• receive, through the reception module, downlink data by demodulating a Physical Downlink Shared Channel (PDSCH) in one or more second RB pairs within the RB bundle based on a downlink channel estimated by using a second DMRS in the one or more second RB pairs,
• wherein the downlink channel estimated by using the second DMRS is estimated based on an assumption that a same precoder is applied to the one or more second RB pairs.

A downlink transmission entity for performing downlink transmission in a wireless communication system, the downlink transmission entity comprising:

• a reception module configured to receive an uplink signal from a downlink reception entity;
• a transmission module configured to transmit a downlink signal to the downlink reception entity;
• and
• a processor configured to control the reception module and the transmission module,
• wherein the processor is further configured to:
• transmit, through the transmission module, in a first resource block (RB) pair within an RB bundle, downlink control information through a Physical Downlink Control Channel (PDCCH) and a first Demodulation Reference Signal (DMRS) used for estimating a downlink channel to demodulate the PDCCH;
• and
• transmit, through the transmission module, in one or more second RB pairs within the RB bundle, downlink data through a Physical Downlink Shared Channel (PDSCH) and a second DMRS used for estimating a downlink channel to demodulate the PDSCH,
• wherein the downlink channel estimated by using the second DMRS is estimated based on an assumption that a same precoder is applied to the one or more second RB pairs.