A method for receiving a broadcast signal in a receiver, the method comprising: receiving broadcast signals including first and second frames, wherein each of the first and second frames includes a preamble and data symbols, wherein the preamble includes a first preamble, P1, symbol including information for indicating a format of the preamble, an additional first preamble, AP1, symbol including additional transmission parameters to identify each of the first and second frames, and at least one P2 symbol including L1 signaling information for signaling the data symbols, and wherein the AP symbol is located between the P1 symbol and at least one P2 symbol; detecting the P1 symbol and the AP1 symbol of each of the first and second frames based on the format of the preamble and the additional transmission parameters, wherein the P1 symbol includes a main part, a first part and a second part, wherein the first part carries a frequency shifted version of a part of the main part while the second part conveys a frequency shifted version of the other part of the main part, wherein (fsh) of frequency shift is applied to the first and second parts, wherein the AP1 symbol includes an additional main part, a third part and a fourth part, wherein the third part carries a frequency shifted version of a part of the additional main part while the fourth part conveys a frequency shifted version of the other part of the additional main part, wherein (-fsh) of frequency shift is applied to the third and fourth parts, and wherein a length of the first part is different from that of the third part and a length of the second part is different from that of the fourth part; demodulating the first and second frames by an OFDM (Orthogonal Frequency Division Multiplexing) scheme; frequency deinterleaving the demodulated first and second frames; parsing the data symbols of the frequency-deinterleaved first and second frames based on the L1 signaling information, and outputting Physical Layer Pipe, PLP, data; time deinterleaving the PLP data; and performing Multi-input Multi-Output, MIMO, decoding on the time-deinterleaved PLP data. receiving broadcast signals including first and second frames, wherein each of the first and second frames includes a preamble and data symbols, wherein the preamble includes a first preamble, P1, symbol including information for indicating a format of the preamble, an additional first preamble, AP1, symbol including additional transmission parameters to identify each of the first and second frames, and at least one P2 symbol including L1 signaling information for signaling the data symbols, and wherein the AP symbol is located between the P1 symbol and at least one P2 symbol; detecting the P1 symbol and the AP1 symbol of each of the first and second frames based on the format of the preamble and the additional transmission parameters, wherein the P1 symbol includes a main part, a first part and a second part, wherein the first part carries a frequency shifted version of a part of the main part while the second part conveys a frequency shifted version of the other part of the main part, wherein (fsh) of frequency shift is applied to the first and second parts, wherein the AP1 symbol includes an additional main part, a third part and a fourth part, wherein the third part carries a frequency shifted version of a part of the additional main part while the fourth part conveys a frequency shifted version of the other part of the additional main part, wherein (-fsh) of frequency shift is applied to the third and fourth parts, and wherein a length of the first part is different from that of the third part and a length of the second part is different from that of the fourth part; demodulating the first and second frames by an OFDM (Orthogonal Frequency Division Multiplexing) scheme; frequency deinterleaving the demodulated first and second frames; parsing the data symbols of the frequency-deinterleaved first and second frames based on the L1 signaling information, and outputting Physical Layer Pipe, PLP, data; time deinterleaving the PLP data; and performing Multi-input Multi-Output, MIMO, decoding on the time-deinterleaved PLP data.