Patent ID: 8705644

Claim:
A method of generating and transmitting an uplink demodulation reference signal (DM-RS) in clustered discrete Fourier transformer (DFT)-spread-orthogonal frequency division multiplexing (OFDM) transmission, the method comprising: allocating one DM-RS sequence to each terminal for uplink transmission, wherein the allocating of the DM-RS sequence comprises allocating a DM-RS sequence having a length corresponding to a sum of numbers of sub-carriers of the RBs allocated to the respective transmitted clusters, and wherein when the length of the DM-RS sequence is equal to or greater than a length corresponding to three RBs, the DM-RS sequence is generated from an extended Zadoff-Chu (ZC) sequence, which is a kind of constant amplitude zero autocorrelation (CAZAC) sequence, and when the length of the DM-RS is smaller than the length corresponding to the three RBs, the DM-RS sequence is generated using a computer-generated (CG)-CAZAC sequence; dividing the allocated DM-RS sequence according to sizes of resource blocks (RBs) allocated to respective transmitted clusters; and mapping divided DM-RS sequences to locations of corresponding DM-RS symbols of the respective clusters for transmission.