1. A method of generating reference signals for N layers (N is one value among 2 to 4) by a User Equipment (UE), the method comprising: receiving a Cyclic Shift (CS) parameter from an eNodeB by the UE; and generating the reference signals for the N layers by applying [+1, +1] as an Orthogonal Cover Code (OCC) of each layer when the CS parameter is one of 011 indicating 4 as a CS parameter value of a first layer and 100 indicating 2 as a CS parameter value of the first layer, and applying [+1, −1] as an OCC of each layer when the CS parameter is one of 101 indicating 8 as a CS parameter value of the first layer and 110 indicating 10 as a CS parameter value of the first layer.