A study on the effect of frequency offset among Transmitters in SFN

Abstract

OFDM(Orthogonal Frequency Division Multiplexing) modulation has excellent characteristic under multipath propagation. Therefore it is possible to construct a SFN(Single Frequency Network). Transmitting frequency is required a high level precision, because SFN is a kind of synchronous broadcasting network. The rate of a receiving bit error is varied by the frequency offset of the SFN transmitters. In the case of DQPSK-OFDM, the frequency difference between the transmitters should be limited to several percents of the carrier spacing to preserve its performance. As for 64QAM-OFDM, the allowable difference is roughly one tenth as small as the former.