Patent ID: 8767646

Claim:
A method of transmitting a demodulation reference signal (DMRS) for a Physical Uplink Shared Channel (PUSCH) at a User Equipment (UE) in a radio communication system, the method comprising: receiving a Physical Downlink Control Channel (PDCCH) signal for the PUSCH, wherein the PDCCH signal includes a 3-bit index related to Cyclic Shift (CS) for the DMRS, the 3-bit index indicating a value; determining a plurality of CS parameters based on the value of the 3-bit index and a number of layers, wherein a number of the plurality of CS parameters is equal to the number of layers; determining a plurality of CS values α λ based on the plurality of CS parameters by using the equation α λ =2π·n CS,λ /12, wherein n CS,λ is a λ th CS parameter of the plurality of CS parameters, λ is an integer in a range from 0 to N−1, and N is the number of layers; and generating a plurality of DMRS sequences based on the plurality of CS values α λ by using the expression e j·α λ ·n · r u,v (n), wherein r u,v (n) is a base sequence, u is a group number, v is a base sequence number within a corresponding group, n is an integer in a range from 0 to N sc RS −1, and N sc RS is a number of allocated subcarriers.