Performance evaluation for AF relay TFI-OFDM systems

Amplify-and-forward (AF) relay transmissions can achieve a low power long distance communication. The problem of the AF method is that the channel state information (CSI) between source-relay (SR) and relay-destination (RD) should be obtained simultaneously in the destination node. The pilot signal is inserted to obtain the CSI, and the time frequency interferometry (TFI) method can reduce the number of pilot signals and the channel estimation (CE) power. This paper proposes the low power CE for AF relay transmissions in an orthogonal frequency division multiplexing based on the TFI method.