Reduced-Rate OFDM Transmission for Inter-Subchannel Interference Self-Cancellation over High-Mobility Fading Channels

In this paper, we develop a general reduced-rate orthogonal frequency division multiplexing (OFDM) transmission scheme for inter-subchannel interference (ICI) self-cancellation over high-mobility fading channels. Via transmit and receive processing, we transform the original OFDM system into an equivalent one with fewer subcarriers. By reducing transmission rate, we are able to design a transmitted signal structure with inherent ICI self-cancellation capability without requiring the instantaneous channel state information. We develop a general structure of transmit and receive processing matrices so that all equivalent subchannels in the transformed OFDM system have the same average signal-to-interference ratio (SIR). For the developed structure, we further optimize the transmit and the receive processing coefficients to maximize the SIR based on channel statistics. Numerical and simulation results demonstrate that the developed reduced-rate OFDM transmission achieves an SIR gain of around 5 dB over the existing ICI self-cancellation schemes and significantly reduces the error floor at the receiver.