A broadcast signal receiver, comprising: a Fast Fourier Transform, FFT, module configured to Orthogonal Frequency Division Multiplexing, OFDM,-demodulate a received broadcast signal, the received broadcast signal carrying a signal frame that includes a preamble and at least one subframe, wherein: the subframe includes data symbols and at least one Subframe Boundary Symbol, SBS, the SBS includes data cells and subframe boundary pilots, the data cells of the SBS includes active data cells and null cells, the null cells are divided into a first set of null cells and a second set of null cells, the first set of null cells are positioned at lowest frequency indices, the second set of null cells are positioned at highest frequency indices, and the active data cells are positioned between the first set of null cells and the second set of null cells; a pilot detector configured to detect pilots including Scattered Pilots, SPs, and the subframe boundary pilots in the broadcast signal, wherein an amplitude of the SPs is determined from a SP boosting parameter for a boosted power level of the SPs and an SP pattern in the signal frame; a frame parsing module configured to parse the signal frame to output Physical Layer Pipe, PLP, data, wherein a number of the active data cells of the SBS for an FFT size and a coefficient value is determined based on the amplitude of the SPs; a demapping and decoding module configured to decode the PLP data; and an output processing module configured to process the PLP data and to output a data stream. a Fast Fourier Transform, FFT, module configured to Orthogonal Frequency Division Multiplexing, OFDM,-demodulate a received broadcast signal, the received broadcast signal carrying a signal frame that includes a preamble and at least one subframe, wherein: the subframe includes data symbols and at least one Subframe Boundary Symbol, SBS, the SBS includes data cells and subframe boundary pilots, the data cells of the SBS includes active data cells and null cells, the null cells are divided into a first set of null cells and a second set of null cells, the first set of null cells are positioned at lowest frequency indices, the second set of null cells are positioned at highest frequency indices, and the active data cells are positioned between the first set of null cells and the second set of null cells; the subframe includes data symbols and at least one Subframe Boundary Symbol, SBS, the SBS includes data cells and subframe boundary pilots, the data cells of the SBS includes active data cells and null cells, the null cells are divided into a first set of null cells and a second set of null cells, the first set of null cells are positioned at lowest frequency indices, the second set of null cells are positioned at highest frequency indices, and the active data cells are positioned between the first set of null cells and the second set of null cells; a pilot detector configured to detect pilots including Scattered Pilots, SPs, and the subframe boundary pilots in the broadcast signal, wherein an amplitude of the SPs is determined from a SP boosting parameter for a boosted power level of the SPs and an SP pattern in the signal frame; a frame parsing module configured to parse the signal frame to output Physical Layer Pipe, PLP, data, wherein a number of the active data cells of the SBS for an FFT size and a coefficient value is determined based on the amplitude of the SPs; a demapping and decoding module configured to decode the PLP data; and an output processing module configured to process the PLP data and to output a data stream.