A broadcast signal receiver includes a tuner configured to receive a broadcast signal; a pilot detector configured to detect pilots included in the broadcast signal; a de-framer configured to de-frame a signal frame of the broadcast signal and to extract Physical Layer Pipe (PLP) data from the signal frame; and a decoder configured to decode the PLP data, wherein the signal frame comprises a bootstrap, a preamble, and the PLP data, wherein the bootstrap comprises first information for indicating system bandwidth, second information for emergency alert wake up, and third information for indicating structure of the preamble, wherein the preamble comprises a plurality of preamble symbols, the preamble carrying Layer 1 (L1) signaling data for the signal frame, and wherein the foremost preamble symbol comprises fourth information indicating a number of at least one remaining preamble symbol.