Methods for transmitting system information, subframe structures, and pilot structures in a wireless access system are disclosed. A method for receiving system information in a wireless access system includes receiving a Network Common Information (NCI) channel including network common system information from a Base Station (BS), receiving a synchronization channel from the BS, for acquiring synchronization with the BS, receiving a Cell Specific Information (CSI) channel including cell specific system information which is specific to the BS from the BS, and decoding the NCI channel and the CSI channel using the synchronization channel. The NCI channel is transmitted over a first frequency channel and the CSI channel is transmitted over a second frequency channel.