1. A method for supporting a variable bandwidth in a wireless communication system, the method comprising:receiving, by a wireless device, a synchronization signal in a first bandwidth;
acquiring, based on the synchronization signal, a second bandwidth for a downlink (DL) channel; and
receiving, by the wireless device, the DL channel in the second bandwidth,
wherein the synchronization signal includes a primary synchronization signal (PSS) for acquiring time/frequency synchronization and a secondary synchronization signal (SSS) for detecting a physical cell identifier (PCI), and
wherein a sequence of the PSS varies depending on a size of the second bandwidth.