Abstract: A method for transmitting scattered pilot signals in a multi-carrier system is disclosed. The method includes: in each time slot, in time dimension, putting each 4 OFDM symbols into a group according to the order of the OFDM symbols; in each group of OFDM symbols, in frequency dimension, selecting, for each OFDM symbol, a plurality of valid sub-carriers to transmit scattered pilots, wherein for a same OFDM symbol, between each 2 valid sub-carriers selected, there are 7 valid sub-carriers; for different OFDM symbols in a same group, the valid sub-carriers selected are interleaving in frequency domain; and transmitting scattered pilot signals on the valid sub-carriers selected. The solution helps the multi-carrier system to handle multi-path channel with large delay spread, to obtain more accurate channel estimation and to achieve better receiving performance.

Abstract: A method, transmitter and modulator for signal synchronization transmission in a single frequency network transmission system are disclosed. The method includes: extracting effective data from data received; performing channel coding, mapping and modulation to the effective data extracted and saving the data modulated into storage; and retrieving the data from the storage upon receiving a pulse indication signal, performing digital-to-analog conversion and baseband-to-radio frequency conversion to the data retrieved and transmitting the data converted into air via antennae. The technical scheme enables different transmitters to transmit signals synchronously.