Abstract
In this thesis, we investigate intercarrier interference (ICI) cancellation for OFDM-based cooperative relay systems using conjugate transmission. First, we modify an existing adaptive receiver for such systems by introducing a new amplitude scaling factor for each subcarrier. The presented amplitude scaling factor is optimized by a carrier-to-interference-plus-noise ratio (CINR) criterion derived under multipath environments, rather than by the carrier-to-interference ratio (CIR) derived under AWGN channels in a previous scheme. With the proposed adaptive receiver, we then develop a relay selection method based on a max-min CINR criterion for OFDM-based cooperative relay systems using conjugate transmission, where the frequency offset and channel state information are jointly considered for relay selection. Computer simulation results demonstrate that the proposed adaptive receiver and the proposed relay selection method outperform previous related schemes in terms of the bit-error-rate performance.