A Doppler-Compensated Noncoherent OFDM-Transceiver With Sectorized Antenna Reception

Frequency-selective fading channels are easily made use of by OFDM. Due to an increase of the symbol duration even channels with large delay spread can be utilized for data-transmission. However, if the channel additionally exhibits a large Doppler spread, a short symbol duration is desirable. Otherwise the channel's time-varying impulse response during one OFDM-symbol will introduce Inter-Carrier-Interference (ICI). This will inevitably produce an error-floor. Ultimately, one has to compromise between achievable data-rate and robustness against fading. The authors present a novel non-coherent receiver which relies on the use of directional antennas to avoid large Doppler spread before it can lead to ICI.