Patent ID: 9571240
Date: 2017-02-14
CPC Classifications: H04L,H04W

Claim:
1. A method of transmitting broadcast signals, the method including: encoding service data of Physical Layer Pipes (PLPs); bit interleaving the encoded service data; building at least one signal frame including the bit interleaved service data; and modulating data in the at least one signal frame by Orthogonal Frequency Division Multiplexing (OFDM) method; inserting a preamble at a beginning of each of the at least one signal frame after the modulating step; and transmitting the broadcast signals having the modulated data, wherein the preamble includes information for a size of Fast Fourier Transform (FFT), a guard interval and a pilot mode, wherein the preamble includes two OFDM symbols, and wherein each of the two OFDM symbols in the preamble includes information for an emergency alert.