Method for changing pattern of reference signals according to rank variation in wireless communication system, and an apparatus therefor

A method for receiving a reference signal from a base station at a user equipment in a wireless communication system, the method comprising:

• receiving the reference signal from the base station according to a first pattern corresponding to a first rank;
• and
• when a rank is changed from the first rank to a second rank, receiving the reference signal from the base station according to a second pattern corresponding to the second rank,
• wherein, when the second rank is greater than the first rank, the second pattern includes the first pattern, and
• wherein a number of reference signal resources in a time domain for each spatial layer in the second pattern is larger than a number of reference signal resources in a time domain for each spatial layer in the first pattern.

A base station in a wireless communication system, the base station comprising:

• a transmitter configured to transmit signals;
• and
• a processor configured to:
• control the transmitter to transmit a reference signal to a user equipment according to a first pattern corresponding to a first rank, and
• control the transmitter to transmit the reference signal to the user equipment according to a second pattern corresponding to a second rank when a rank is changed to the second rank from the first rank,
• wherein, when the if the second rank is greater than the first rank, the second pattern includes the first pattern, and
• wherein a number of reference signal resources in a time domain for each spatial layer in the second pattern is larger than a number of reference signal resources in a time domain for each spatial layer in the first pattern.

A user equipment in a wireless communication system, the user equipment comprising:

• a receiver configured to receive signals;
• and
• a processor configured to:
• control the receiver to receive a reference signal from a base station according to a first pattern corresponding to a first rank, and
• control the receiver to receive the reference signal from the base station according to a second pattern corresponding to a second rank when a rank is changed to a second rank from the first rank,
• wherein, when the second rank is greater than the first rank, the second pattern includes the first pattern, and
• wherein a number of reference signal resources in a time domain for each spatial layer in the second pattern is larger than a number of reference signal resources in a time domain for each spatial layer in the first pattern.