Patent ID: 8837452

Claim:
A method for transmitting a Channel State Information-Reference Signal (CSI-RS), the method comprising: generating a CSI-RS sequence for N antenna ports, the number N being an integer larger than or equal to 1; mapping the generated CSI-RS sequence to Resource Elements (REs) for a transmission of the CSI-RS; and generating an Orthogonal Frequency Division Multiplexing (OFDM) signal including the mapped CSI-RS sequence and transmitting the generated OFDM signal to a User Equipment, wherein ┌N/2┐ antenna port sets are determined from the N antenna ports, wherein the mapped CSI-RS sequence for antenna ports in one of the ┌N/2┐ antenna port sets is mapped to REs designated for the antenna port set, the mapped CSI-RS sequence for each of the antenna ports in the antenna port set being discriminated from each other by orthogonal codes, wherein, for the mapping of the generated CSI-RS sequence, first REs and second REs designated for two adjacent antenna port sets of the ┌N/2┐ antenna port sets, respectively, within a resource block are spaced apart from each other having 2 REs between the first REs and the second REs in a frequency axis, and wherein REs designated for one of the ┌N/2┐ antenna port sets correspond to one sub-carrier at every 12 sub-carriers and two OFDM symbols within a sub-frame.