OFDM receivers using oversampling with rational sampling ratios

Abstract

In this paper, we propose orthogonal frequency division multiplexing (OFDM) receivers using oversampling, where the oversampling ratio is extended from integers to rational numbers. We propose several receiver structures with the same oversampling ratio which reveal the same performance. If we increase the sampling rate above the symbol rate for the OFDM signal, subcarriers with higher frequencies than we want are obtained. Removing the unwanted higher frequency subcarriers means reducing the noise only subcarriers. By using this characteristic of OFDM signals, signal-to-noise ratio (SNR) gain is obtained by the oversampling ratio compared to the receivers which use symbol rate sampling. Through computer simulations, we verify the proposed method.