LAUSR

In order to improve the reliability of the OFDM systems, this paper proposes the variable modulation scheme based on the condition of the channel between the transmitter and the receiver. The proposed scheme uses the codebook that is stored in advance at the transmitter and the receiver. The key idea of the variable modulation scheme is to use the similarity with the condition of the channel between the adjacent subcarriers in the OFDM system. From the simulation results, the proposed scheme has about 3 dB SNR gain at the BER of $$10^{-3}$$10-3 compared to the conventional scheme.