Patent ID: 9496934
Filing Date: 2016-11-15
CPC Classification: H04B,H04J,H04L

Claim Text:
1. A method for transmitting a downlink signal by a base station in a wireless communication system, the method comprising: receiving first and second precoding matrix indicators (PMIs) from a user equipment; determining a first matrix W precoding the downlink signal using two or more layers onto which the downlink signal mapped and the determined precoding matrix W; and transmitting the precoded downlink signal to the user equipment, wherein all precoding vectors included in the precoding matrix W have a property that phases of the all precoding vectors increase in proportion to precoding vector indexes and are orthonormal to each other, wherein: the first codebook is configured according to the following equation, Wn is configured according to the following equation, k is a precoding vector index of the first codebook; the second codebook is configured according to the following equation, e and l is a precoding vector index of the second codebook.