Pilot tone selection in OFDM amplified-and-forward relay system

Channel estimation for OFDM amplify-and-forward relay system requires transmission of pilot tones in source node, and different pilot tones can be derived according to different channel estimation algorithms and OFDM scenarios. This paper derives two different pilot tones with different scenarios: 1) no virtual subcarrier is applied in OFDM system and LS algorithm is used in channel estimation; 2) virtual subcarriers are applied in OFDM system and RLS algorithm is used in channel estimation.