Synchronisation in multicarrier systems

摘要

An OFDM modulator is disclosed which comprises a modulator for modulating an input symbol stream into OFDM modulated subcarrier signals and a circuit for including a level-raised reference subcarrier signal for each symbol in the OFDM subcarrier signals. The reference subcarrier signals are used for synchronization in an OFDM demodulator. Each of the reference subcarrier signals is assigned to the center subcarrier of the OFDM subcarrier signals. In OFDM demodulation, an AGC (automatic gain control) circuit controls the level of received OFDM modulated subcarrier signals at a raised tracking rate through the peak detection of reference subcarrier signals in the received OFDM modulated subcarrier signals. <IMAGE>