In wireless technology, a delay diversity OFDM (DD OFDM) transmission scheme in amplify-and-forward (AF)
full-duplex relay systems was designed by equivalent mathematical steps. One direct source-to destination
link, one relay forwarding link and residual self-interference(RSI) are considered in the system. The necessary
cyclic prefix (CP) length is investigated and a suitable AF relay protocol in the full-duplex relay OFDM system was developed.