The present invention relates to a wireless communication system, and more specifically, disclosed are a method and an apparatus for transmitting or receiving a downlink signal by considering an antenna port relationship. A method for user equipment receiving a physical downlink shared channel (PDSCH) signal in the wireless communication system, according to one embodiment of the present invention, comprises the steps of: determining a start symbol index of the PDSCH from a downlink subframe; and receiving the PDSCH signal based on the start symbol index, wherein the PDSCH can be scheduled by means of downlink control information (DCI) which is received through a physical downlink control channel (PDCCH) or an enhanced PDCCH (EPDCCH). When the DCI is comprised according to DCI format 1A, which is transmitted through the EPDDCH, and the downlink subframe is a non-multicast broadcast single frequency network (MBSFN) subframe, the start symbol index can be determined depending on an EPDCCH start symbol value which is established by an upper layer.