This paper describes a new technique to realize SFN that utilizes an OFDM. In the SFN environment, especially in relay environment, sometimes, delay spread is longer than guard-intervals. In this case, it generates not only ISI(inter-symbol interference), but also ICI(inter-carrier interference), since orthogonality would be lost. To improve this affection, the relay station must remove the delay, but is impossible. Now, we change our scheme oppositely, that is to insert the delay on the relay station by torelating ISI to avoid ICI, which is more difficult to eliminate than ISI. In this paper, the method to eliminate ISI using Viterbi algorithm is also proposed. As the experimental result, it is shown that service area is spread, since torelable delay becomes longer than conventional system. Moreover, and BER characteristics are improved even in the service area of conventional system, since frequency-selective fading is not brought by using proposed system.
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