A method and device for transmitting data symbols using an antenna correlation in a wireless access system supporting multiple input/multiple output (MIMO) operations. The method includes: receiving, from a receiving end, grouping information of a plurality of antennas for supporting the MIMO operations, where the grouping information includes information on the two selected antenna subgroups; selecting two antennas of which a correlation is highest from the two selected antenna subgroups respectively for transmitting the data symbols; and transmitting different data symbols through each of the two selected antennas of the two selected antenna subgroups on an identical time frequency resource. Here, antennas with a highest correlation are grouped into two or more antenna subgroups. Also, two antenna subgroups, of which a correlation is lowest from the two or more antenna subgroups, are selected among the two or more antenna subgroups by the receiving end.