A method of generating user equipment, UE, specific reference signals at a base station of a wireless communication system, wherein the base station includes a plurality of antennas, the method comprising: generating a reference signal sequence for a plurality of antenna ports used for data transmission, wherein the plurality of antenna ports comprises more than 8 antenna ports; mapping the reference signal sequence to a resource region respectively allocated to each of the plurality of antenna ports; generating respective UE specific reference signals for each of the plurality of the antenna ports; and transmitting to a UE downlink UE specific reference signals via a subframe onto which the reference signal sequence is mapped for the plurality of antenna ports, wherein a resource region for UE specific reference signals for 8 antenna ports among the plurality of antenna ports is different from a resource region for one or more UE specific reference signals for remaining antenna ports among the plurality of antenna ports, wherein a resource region for a UE specific reference signal for a ninth antenna port among the plurality of antenna ports is identical to a resource region for a UE specific reference signal for a tenth antenna port among the plurality of antenna ports, wherein the UE specific reference signal for the ninth antenna port and the UE specific reference signal for the tenth antenna port are multiplexed based on a code division multiplexing, CDM, scheme, and wherein a physical downlink shared channel, PDSCH, is transmitted by mapping it to a resource region for a UE specific reference signal for not used antenna port among the remaining antenna ports included in the plurality of antenna ports. generating a reference signal sequence for a plurality of antenna ports used for data transmission, wherein the plurality of antenna ports comprises more than 8 antenna ports; mapping the reference signal sequence to a resource region respectively allocated to each of the plurality of antenna ports; generating respective UE specific reference signals for each of the plurality of the antenna ports; and transmitting to a UE downlink UE specific reference signals via a subframe onto which the reference signal sequence is mapped for the plurality of antenna ports, wherein a resource region for UE specific reference signals for 8 antenna ports among the plurality of antenna ports is different from a resource region for one or more UE specific reference signals for remaining antenna ports among the plurality of antenna ports, wherein a resource region for a UE specific reference signal for a ninth antenna port among the plurality of antenna ports is identical to a resource region for a UE specific reference signal for a tenth antenna port among the plurality of antenna ports, wherein the UE specific reference signal for the ninth antenna port and the UE specific reference signal for the tenth antenna port are multiplexed based on a code division multiplexing, CDM, scheme, and wherein a physical downlink shared channel, PDSCH, is transmitted by mapping it to a resource region for a UE specific reference signal for not used antenna port among the remaining antenna ports included in the plurality of antenna ports. <EOS>